HK1243720A1

HK1243720A1 - Copolymer

Info

Publication number: HK1243720A1
Application number: HK18103131.4A
Authority: HK
Inventors: 亘堀江; 雄一郎竹山; 惠加治; 厚志仁王; 萌露木; 纱弥香佐藤; 紗彌香佐藤
Original assignee: 宝丽化学工业有限公司
Priority date: 2015-05-11
Filing date: 2016-05-11
Publication date: 2018-07-20
Also published as: CN111358713B; CN111481469B; CN111358713A; CN111481469A; CN111329788B; AU2016261772A1; CN111329787B; CN111329787A; TW201708278A; CN107614551A; CN111329788A; TWI690541B; WO2016182006A1; SG11201709288VA; AU2016261772B2

Abstract

The present invention addresses the problem of providing a novel copolymer having an elastic feeling. A copolymer having a weight-average molecular weight of 20,000-110,000, having one or more types of constituent units (a) derived from a hydrophobic monomer having a specific structure, and one or more types of constituent units (b) derived from a hydrophilic monomer represented by general formula (2) as essential constituent units.

Description

Copolymer

Technical Field

The present invention relates to novel copolymers, i.e., copolymers of hydrophobic monomers and hydrophilic monomers.

Also, the present invention relates to an emulsified composition emulsified by the water-soluble copolymer.

Also, the present invention relates to a skin cleansing milk comprising the water-soluble copolymer.

Also, the present invention relates to a sunscreen cosmetic comprising the water-soluble copolymer.

The present invention also relates to a coating film having an island-in-sea structure in which island particles of an amphiphilic copolymer are dispersed in the sea of an aqueous gel, and a composition for forming the coating film.

Background

Generally, oils are excellent in feeling of use such as elasticity and moisture retention, and have been used as materials for cosmetics. However, although the oil agent exerts the above-mentioned excellent feeling of use, when it is blended at a high content, stickiness may occur to deteriorate the feeling of use.

Under such circumstances, attempts have been made to alleviate the sticky feeling caused by the oil agent by devising the composition and structure of the cosmetic. For example, patent document 1 proposes a technique for suppressing stickiness by reducing the emulsion particle size in a cosmetic preparation of an emulsion composition.

However, there is a problem that the technique of reducing stickiness by designing the composition and structure of a cosmetic and the like as described in patent document 1 is limited to applicable formulations.

On the other hand, a novel material having both a moisturizing feeling and a non-adhesive feeling in use has been proposed. For example, patent document 2 discloses a cosmetic base composed of an alkylene oxide derivative having excellent touch and moisture retention properties.

Also, emulsion compositions in which an oil phase component and an aqueous phase component are mixed with an emulsifier are widely used as cosmetic formulations. However, general low-molecular emulsifiers sometimes cause problems such as irritation and stickiness to the skin.

In order to solve such problems, in recent years, various emulsification techniques using a polymeric emulsifier have been proposed.

Patent document 3 discloses an emulsion composition using hydroxyethyl cellulose as an emulsifier.

Further, patent document 4 discloses an emulsion composition using an alkyl-modified carboxyvinyl polymer as an emulsifier.

In addition, potassium salts of higher fatty acids have been widely used in skin cleansing milks such as face washes because of their good foamability, good cleansing power, and a clean feeling after rinsing. However, although the skin cleansing milk containing a potassium salt of a higher fatty acid as a main component has such excellent properties, it has the following problems: it is difficult to obtain emulsion-like foam quality, the skin is easily excessively degreased at the time of cleansing, and soap stains (scum) remain on the skin, and the skin is easily stretched after use.

In order to improve these problems, the following methods are proposed: the combination use of a higher fatty acid and a surfactant such as an acyltaurate type, an acylisethionate type, a phosphate type, or an acylamino acid type (for example, patent document 5), and the formulation of additives other than the surfactant (for example, a silicone compound, a specific glycolipid, raffinose, a plant seed mucilage, various polymer compounds, and the like) (for example, patent documents 6 to 12).

Also, attempts have been made to improve the above-mentioned problems by combining an acylglycine type surfactant and a specific high molecular compound without using a potassium salt of a higher fatty acid as a main component (see patent document 13).

Further, the oil-in-water emulsion type sunscreen cosmetic has a refreshing feeling of use and is easy to be used continuously. In order to improve the ultraviolet protection effect, ultraviolet absorbers and ultraviolet scattering agents, which are metal oxide powders such as zinc oxide and titanium oxide, have been used in oil-in-water emulsion cosmetics. However, when a large amount of the ultraviolet absorber is blended, there is a problem that discoloration occurs, the diffusibility is poor, and the feeling of use such as stickiness is poor. Further, when a large amount of metal oxide powder is blended, there is a problem that not only coagulation and sedimentation of the powder occur with time, but also the viscosity is lowered, and the stability with time such as emulsification separation and precipitation is lowered. When these are used together, the above problem tends to occur more easily.

In order to solve these problems, it has been proposed to use an ultraviolet absorber such as a dibenzoylmethane derivative together with titanium oxide treated with silane and/or siloxane (see patent document 14).

Oil-in-water emulsion cosmetics using a water-soluble polymer such as polyacrylamide, xanthan gum, or a (sodium acrylate/acryloyldimethyltaurine) copolymer have also been proposed (see patent documents 15 and 16).

The sea-island structure is a structure in which two kinds of polymers that are not compatible with each other are phase-separated, and a dispersed phase (island phase) containing one kind of polymer is dispersed in a continuous phase (sea phase) containing the other kind of polymer. Thus, the sea-island structure has a different property from the composition having a uniform structure because it has a phase-separated heterogeneous structure. In order to utilize these properties, research and development in the technical fields related to plastics, rubbers, toners, adhesives, and the like have been actively conducted with respect to the sea-island structure.

For example, patent document 17 discloses a tire covered with a covering mixture having a sea-island structure comprising a sea phase and an island phase, wherein the sea phase comprises a thermoplastic resin and the island phase comprises a polyurethane-based thermoplastic elastomer.

However, there has been no attempt to utilize the sea-island structure in the cosmetic field so far.

Patent document 18 discloses an external skin preparation containing an amphiphilic copolymer having a structural unit derived from a specific hydrophobic acrylate monomer and a structural unit derived from a specific hydrophilic acrylate monomer.

Patent document 1: japanese laid-open patent publication No. 2012-116783

Patent document 2: japanese re-listing 2006/038724

Patent document 3: japanese patent laid-open publication No. 2011-231049

Patent document 4: japanese laid-open patent publication No. H09-019631

Patent document 5: japanese laid-open patent publication No. 6-248298

Patent document 6: japanese laid-open patent publication No. 10-77206

Patent document 7: japanese patent laid-open No. 2001-72574

Patent document 8: japanese patent laid-open No. 2000-178172

Patent document 9: japanese laid-open patent publication No. 11-209799

Patent document 10: japanese patent laid-open publication No. 2003-73257

Patent document 11: japanese patent laid-open publication No. 2007 and 277140

Patent document 12: japanese laid-open patent publication No. 10-183193

Patent document 13: japanese laid-open patent publication No. 9-78082

Patent document 14: japanese laid-open patent publication No. 9-2929

Patent document 15: japanese patent laid-open publication No. 2003-104859

Patent document 16: japanese laid-open patent publication No. 2010-215602

Patent document 17: japanese patent laid-open publication No. 2013-180652

Patent document 18: japanese patent laid-open No. 2014-9189

As described above, although the oil agent has a preferable feeling of use such as elasticity, it also has a problem such as stickiness. Under such circumstances, a new material having an elastic feeling like an oil agent is demanded.

Disclosure of Invention

The present invention addresses the problem of providing a novel copolymer having an elastic feel. In a preferred embodiment of the present invention, a first object is to further provide a copolymer which is less likely to cause stickiness and has a moist feeling.

The polymer emulsifier described above has advantages such as less irritation to the skin and less viscosity at a low concentration content, but has a lower emulsifying power than conventional low-molecular emulsifiers. Therefore, in order to ensure the stability of the emulsified state, it is necessary to highly blend a polymer emulsifier in the emulsified composition to achieve a high viscosity, which results in a problem of generating stickiness.

In view of such circumstances, a second object of the present invention is to provide an emulsion composition which is less irritating to the skin, less sticky, and excellent in emulsion stability.

With the recent increase in consumer demand, particularly with respect to foam quality and clean touch, these methods are not sufficiently satisfactory, and further improvement is desired.

In view of such circumstances, a third object of the present invention is to provide a novel technique for reducing the skin tightness after using a skin cleansing cream.

A fourth object of the present invention is to provide a technique for reducing the feeling of skin tightness after use without impairing the advantageous effects inherent in skin cleansing creams such as cleanliness, good foamability, good foam quality, no sticky feeling after use, and easy spreadability on the skin.

Further, in the technical field of oil-in-water type sunscreen cosmetics, it is a problem to make ultraviolet protection function compatible with both feeling of use and emulsion stability. Various techniques have been proposed to solve this problem, but these techniques are insufficient.

In view of the above circumstances, a fifth object of the present invention is to provide an oil-in-water sunscreen cosmetic composition having excellent ultraviolet protection function, non-stickiness, excellent feeling in use such as moisture retention, and emulsion stability.

Another object of the present invention is to provide a coating film having a sea-island structure mainly composed of a water-soluble component, and a technique for forming the coating film. Further, a technique for providing a film mainly containing a water-soluble component to impart a feeling of touch in the form of an emulsion containing an oil agent is provided. Preferably, a sixth object of the present invention is to provide a coating film having both moisture retention and flexibility, and a technique for forming the coating film.

In view of the background of the first problem, the present inventors have conducted extensive studies on an elastic copolymer, and as a result, they have found that a copolymer obtained by polymerizing an acrylic monomer having a hydrophobic polymerizable carboxyl group and two types of acyl groups having a specific branched structure and a hydrophilic acrylic monomer having a specific structure has excellent solubility, particularly solubility in water, and has a touch feeling as elastic as an oil agent, and have completed the present invention. Namely, the present invention is as follows.

A copolymer having, as essential structural units, one or more structural units (a) derived from a hydrophobic monomer represented by the following general formula (1) and one or more structural units (b) derived from a hydrophilic monomer represented by the following general formula (2), and having a weight average molecular weight of 20000 to 110000,

general formula (1)

[ chemical formula 1]

(in the general formula (1), R1 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R2 and R3 may be the same or different and each represents an acyl group having 6 to 22 carbon atoms and having a branched chain and not containing a ring structure, and X represents a group obtained by removing an OH group from a triol.)

General formula (2)

[ chemical formula 2]

(in the general formula (2), R4 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R5 represents an alkylene group having 2 to 4 carbon atoms which may have a hydroxyl group, R6 represents a hydrogen atom, an aromatic hydrocarbon group having 6 to 10 carbon atoms, an aliphatic hydrocarbon group having 1 to 14 carbon atoms or an acyl group having 1 to 12 carbon atoms. n represents an integer of 6 to 40.)

The copolymer has elasticity, no stickiness, and moisture retention when applied to skin.

In a preferred embodiment of the present invention, the mass ratio of the structural unit (a) to the structural unit (b) is 25:75 to 35: 65.

The copolymer having the mass ratio of the structural unit (a) to the structural unit (b) in the above range has excellent elasticity and non-tackiness feeling in use.

In a preferred embodiment of the present invention, the molar ratio of the structural unit (a) to the structural unit (b) is 35:65 to 46: 54.

In a preferred embodiment of the present invention, the hydrophobic monomer is a hydrophobic monomer represented by the following general formula (3).

General formula (3)

[ chemical formula 3]

(in the general formula (3), R7 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R8 and R9 may be the same or different and represent an acyl group having 10 to 22 carbon atoms and a branched chain, which does not have a ring structure, or an acyl group having 6 to 9 carbon atoms and 2 or more branched chains, which does not have a ring structure, Y represents a group obtained by removing an OH group from a triol.)

By using the monomer as a hydrophobic monomer, a copolymer having more excellent touch can be obtained.

In a preferred embodiment of the present invention, the hydrophilic monomer is a hydrophilic monomer represented by the following general formula (4),

general formula (4)

[ chemical formula 4]

(in the general formula (4), R10 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R11 represents a hydrogen atom, an aromatic hydrocarbon group having 6 to 10 carbon atoms, an aliphatic hydrocarbon group having 1 to 14 carbon atoms, or an acyl group having 1 to 12 carbon atoms. m represents an integer of 6 to 40.)

By using the monomer as a hydrophilic monomer, a copolymer having more excellent touch can be obtained.

In a preferred embodiment of the present invention, the trihydric alcohol is glycerin, trimethylolpropane, or trimethylolethane.

By adopting such a manner, the feeling of elasticity can be improved.

The hydrophobic monomer is a compound represented by the following general formula (5),

general formula (5)

[ chemical formula 5]

(in the general formula (5), R12 and R13 may be the same or different and each represents an acyl group having 18 carbon atoms and having no cyclic structure and a branched chain.)

By using such a hydrophobic monomer, the feeling of elasticity can be improved.

In a preferred embodiment of the present invention, the hydrophilic monomer is a hydrophilic monomer represented by the following general formula (6),

general formula (6)

[ chemical formula 6]

(in the general formula (6), I represents an integer of 6 to 40.)

By using such a hydrophilic monomer, the feeling of elasticity can be improved.

The present invention also relates to an external preparation for skin containing the copolymer of the present invention. The skin external preparation has elastic feeling after being applied to skin. Further, it was non-tacky and had an excellent moist feeling.

The present invention for solving the second problem is an emulsion composition comprising a water-soluble copolymer having, as essential constituent units, one or more constituent units (c) derived from a hydrophobic monomer represented by the following general formula (1), the following general formula (7) or (8), and one or more constituent units (d) derived from a hydrophilic monomer, the emulsion composition being substantially free of an emulsifier other than the water-soluble copolymer,

general formula (7)

[ chemical formula 7]

(in the general formula (7), R14 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R15 represents a branched hydrocarbon group having 13 to 30 carbon atoms and no ring structure, or a hydrocarbon group having 6 to 12 carbon atoms and two or more branches and no ring structure.)

General formula (8)

[ chemical formula 8]

(in the general formula (8), R16 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R17, R18 and R19 may be the same or different and represent a branched acyl group having 6 to 22 carbon atoms and containing no cyclic structure, and Y represents a group obtained by removing an OH group from a tetrahydric alcohol.)

The emulsion composition of the present invention contains the water-soluble copolymer, and therefore, the viscosity at the time of use is low.

In a preferred embodiment of the present invention, the hydrophilic monomer is one or two or more hydrophilic monomers selected from the group consisting of: a polymerizable carboxylic acid, a hydrophilic monomer represented by the general formula (2), a hydrophilic monomer represented by the general formula (9), a hydrophilic monomer represented by the general formula (10), and a hydrophilic monomer represented by the general formula (11).

General formula (9)

[ chemical formula 9]

(in the general formula (9), R20 represents a hydrogen atom or a methyl group.)

General formula (10)

[ chemical formula 10]

(in the general formula (10), R21 represents a hydrogen atom or a methyl group, G-O-represents a group obtained by removing hydrogen from a hydroxyl group at the 1-position of a reducing sugar, m represents 2 or 3, and l represents an integer of 1 to 5.)

General formula (11)

[ chemical formula 11]

(in the general formula (11), R22 represents a hydrogen atom or a methyl group, R23 represents an amino acid residue, a polyamine residue or an aminoalcohol residue, Q represents an oxygen atom or a group represented by NH.)

The viscosity of the emulsion composition of the present invention in use can be further reduced by including such a water-soluble copolymer containing a structural unit (d) derived from a hydrophilic monomer.

In a preferred embodiment of the present invention, the hydrophobic monomer is a hydrophobic monomer represented by the general formula (1), and the water-soluble monomer is a hydrophilic monomer represented by the general formula (2).

Such a water-soluble copolymer having a structural unit derived from a hydrophobic monomer and a hydrophilic monomer has excellent emulsifying power and is excellent in the effect of reducing the viscosity of the emulsion composition of the present invention when used.

In a preferred embodiment of the present invention, the content of the water-soluble copolymer is 0.5 to 30% by mass.

By setting the content of the water-soluble copolymer in the range, the stability of the emulsified composition can be improved.

In a preferred embodiment of the present invention, the content of the oil phase component is 0.1 to 70% by mass.

The emulsion composition of the present invention having the oil phase component content in the range described above has excellent stability.

The emulsion composition of the present invention is preferably used as a cosmetic because it is less viscous.

The present invention also relates to an emulsifier comprising a water-soluble copolymer having, as essential structural units, one or more structural units (c) derived from a hydrophobic monomer represented by the general formula (1), (7) or (8) and one or more structural units (d) derived from a hydrophilic monomer.

This emulsifier is low in irritation and at the same time has excellent emulsifying power.

The present invention also relates to a method for producing an emulsified composition, comprising a step of emulsifying the composition by using the emulsifier, wherein an emulsifier other than the emulsifier is not substantially used.

According to this method, an emulsion composition can be easily produced without using a conventional emulsifier which generates stickiness and without highly formulating an emulsifier.

The present invention for solving the third and fourth problems also relates to a skin cleansing milk containing a water-soluble copolymer having, as essential structural units, one or more structural units (e) derived from a hydrophobic monomer represented by the general formula (1), (7) or (8) and one or more structural units (f) derived from a hydrophilic monomer.

The skin cleansing milk of the present invention has good foaming and cream-like foam qualities by containing the water-soluble copolymer, while achieving a reduction in the feeling of tightness after use.

In a preferred mode of the present invention, the hydrophilic monomer is one or two or more hydrophilic monomers selected from the group consisting of: a polymerizable carboxylic acid, a hydrophilic monomer represented by the general formula (2), a hydrophilic monomer represented by the general formula (9), a hydrophilic monomer represented by the general formula (10), and a hydrophilic monomer represented by the general formula (11).

By including such a water-soluble copolymer containing a structural unit (e) derived from a hydrophilic monomer, the feeling of tightness after use of the skin cleansing milk of the present invention can be further reduced.

By including such a water-soluble copolymer containing a structural unit derived from a hydrophobic monomer and a hydrophilic monomer, the feeling of tightness after use of the skin cleansing milk of the present invention can be further reduced.

In an embodiment of the present invention, the content of the water-soluble copolymer is 0.1 to 20% by mass.

By setting the content of the water-soluble copolymer within the above range, the sticky feeling upon use of the skin cleansing milk of the present invention can be reduced.

The invention is preferably applied to foaming cleaners.

According to the present invention, the foaming and foam quality of the foaming cleanser are not inhibited, and the skin tightness after use can be reduced.

The present invention is preferably applied to a gel-like skin cleansing milk.

According to the present invention, the spreadability of the gel-like skin cleansing cream on the skin can be improved, and the feeling of tightness of the skin after use can be reduced.

The skin cleansing milk containing the surfactant has strong cleaning power, so that the skin cleansing milk has strong tightness after use. Therefore, the present invention is preferably applied to a skin cleansing milk containing a surfactant system. According to the invention, the excellent cleaning power of the surfactant is not damaged, or the skin tightness of the skin cleaning milk after use can be reduced while the cleaning power of the surfactant is improved.

The skin cleansing cream containing the fatty acid soap is excellent in foaming, has cream-like foam quality, is excellent in cleansing power, and yet feels strong tightness after use. Therefore, the present invention is preferably applied to a skin cleansing milk in a manner of containing a fatty acid soap. According to the present invention, the skin-cleansing milk containing a fatty acid soap can reduce the feeling of skin tightness after use without impairing the advantageous effects of the milk.

In a preferred embodiment of the present invention, the ratio of the content of the water-soluble copolymer to the content of the fatty acid soap is 1:500 to 1:2, preferably 1:200 to 1:3, and more preferably 1:100 to 1: 5.

By setting the content of the water-soluble copolymer to the range, the skin cleansing milk containing the fatty acid soap can be more effectively reduced in the tense feeling after use.

The present invention is also preferably applied to skin cleansing milk containing a nonionic surfactant.

According to the present invention, it is possible to improve the cleansing power of a skin cleansing milk containing a nonionic surfactant and reduce the feeling of skin tightness after use.

In a preferred embodiment of the present invention, the content ratio by mass of the water-soluble copolymer to the nonionic surfactant is 1:20 to 1:0.5, preferably 1:15 to 1:0.7, and more preferably 1:10 to 1:1.

When the content ratio of the water-soluble copolymer to the nonionic surfactant is in the above range, the feeling of tightness after use can be more effectively reduced.

The present invention for solving the fifth problem is an oil-in-water type sunscreen cosmetic composition comprising the components (a) to (D).

(A) A water-soluble copolymer having, as essential structural units, one or two or more structural units (g) derived from a hydrophobic monomer represented by the general formula (1), (7) or (8) and one or two or more structural units (h) derived from a hydrophilic monomer;

(B) a polyglycerin fatty acid ester obtained by ester condensation of a polyglycerin having a polymerization degree of 10 in 1 molecule and a fatty acid having 16 or more carbon atoms in 2 to 5 molecules;

(C) ionic surfactant

(D) UV scattering agent and/or UV absorber

The sunscreen cosmetic of the present invention has an ultraviolet ray protective function, and is less sticky and excellent in moisture retention. Also, the sunscreen cosmetic of the present invention has emulsion stability.

In a preferred embodiment of the present invention, the hydrophilic monomer is one or two or more hydrophilic monomers selected from the group consisting of: the polymerizable carboxylic acid is a hydrophilic monomer represented by the above general formula (2), a hydrophilic monomer represented by the following general formula (9), a hydrophilic monomer represented by the above general formula (10), and a hydrophilic monomer represented by the above general formula (11).

By using such a water-soluble copolymer containing a structural unit (h) derived from a hydrophilic monomer, the feeling of use such as less stickiness and a moisturizing feeling can be improved.

Sunscreen cosmetics comprising such a water-soluble copolymer having a structural unit derived from a hydrophobic monomer and a hydrophilic monomer have more excellent feeling in use.

In a preferred embodiment of the present invention, the component (C) is an anionic surfactant.

The emulsion stability can be further improved by using an anionic surfactant as the ionic surfactant. Furthermore, the sunscreen cosmetic composition of the present invention using an anionic surfactant also has excellent feeling of use.

In a preferred embodiment of the present invention, the anionic surfactant is sodium acyl lactate.

The emulsion stability can be further improved by using sodium acyl lactate as the anionic surfactant. Further, the sunscreen cosmetic of the present invention using sodium acyl lactate also has excellent feeling in use.

In a preferred embodiment of the present invention, the component (B) is polycarbonate pentastearate-10.

The sunscreen cosmetic of the present invention containing the polycarbonate pentastearate-10 has excellent emulsion stability and feeling of use.

In a preferred embodiment of the present invention, the component (D) is a water-dispersible ultraviolet scattering agent.

Since the water-dispersible ultraviolet scattering agent is uniformly dispersed in the aqueous phase, the sunscreen cosmetic in this manner has an excellent ultraviolet protection function.

In a preferred embodiment of the present invention, the water-dispersible ultraviolet scattering agent is an ultraviolet scattering agent surface-treated with sodium polyacrylate.

The sunscreen cosmetic has the advantages of uniform dispersion of the ultraviolet scattering agent and excellent ultraviolet protection function.

The present invention for solving the sixth problem is a composition comprising: an amphiphilic copolymer having one or more kinds of structural units (i) derived from a hydrophobic monomer and one or more kinds of structural units (j) derived from a hydrophilic monomer as essential structural units,

by the evaporation of the water, a coating film having a sea-island structure in which island particles containing the amphiphilic copolymer are dispersed in an aqueous gel formed of the water-soluble polymer and/or a salt thereof is formed.

The coating film has a sea-island structure mainly composed of a water-soluble component and has a feeling of emulsion containing an oil agent. According to the composition of the present invention, a coating film having such an island-in-the-sea structure can be formed on the skin.

In a preferred embodiment of the present invention, the island particles have an average major axis to minor axis ratio of 0.8 or more, and the island particles having an average particle diameter of 1 to 5 μm have a number particle size distribution of 80% or more.

The coating film having such structural features has excellent moisture retention and flexibility.

Then, the composition of the present invention can easily form a coating film having such excellent properties by being applied to the skin.

In a preferred embodiment of the present invention, the water-soluble polymer is one or more water-soluble polymers selected from the group consisting of acrylic water-soluble polymers, water-soluble polypeptides and water-soluble polysaccharides, and/or salts thereof.

By using a system including such a water-soluble polymer, the water solubility of the components of the composition is improved, and the occurrence of precipitation is suppressed, whereby the stability of the composition can be improved.

In a preferred embodiment of the present invention, the water-soluble polymer is at least one or more water-soluble polymers selected from the group consisting of sodium polyacrylate, (acrylic acid ester/alkyl acrylate (C10-30)) crosslinked polymer, sodium polyglutamate, xanthan gum and angelica dahurica polysaccharide.

By using a system including such a water-soluble polymer, the stability of the composition can be further improved.

In a preferred form of the invention, the composition comprises a polyol which promotes phase separation of the aqueous gel and the amphiphilic copolymer and/or a polyol which inhibits phase separation of the aqueous gel and the amphiphilic copolymer.

By including such a polyhydric alcohol, the uniformity of the coating film can be improved.

In a preferred embodiment of the present invention, the polyol which promotes the phase separation is a polyol which increases the cloud point of an aqueous solution of a nonionic surfactant having a polyether chain in a hydrophilic part by mixing with the aqueous solution,

the polyol which suppresses the phase separation is a polyol in which the cloud point of an aqueous solution is lowered by mixing with the aqueous solution of a nonionic surfactant having a polyether chain in a hydrophilic part.

In a preferred embodiment of the present invention, the polyol which promotes the phase separation is one or two or more polyols selected from the group consisting of 1, 3-butanediol and polyethylene glycol.

By using such a polyol, the phase separation of the hydrogel and the amphipathic copolymer can be effectively promoted, and the uniformity of the coating film can be improved.

In a preferred embodiment of the present invention, the polyol that suppresses the phase separation is one or two or more polyols selected from the group consisting of glycerin, diglycerin, sorbitol, and maltitol.

In a preferred embodiment of the present invention, the mass ratio of the total amount of the polyol which promotes the phase separation and the polyol which suppresses the phase separation to the total amount of the amphiphilic copolymer and the water-soluble polymer is 5:1 to 20: 1.

In this way, the uniformity of the coating film can be improved.

In a preferred embodiment of the present invention, the mass ratio of the polyol which promotes the phase separation to the polyol which suppresses the phase separation is 3.5:1 to 1: 2.5.

In this way, the uniformity of the coating film can be improved.

In a preferred embodiment of the present invention, the content of the amphiphilic copolymer is 0.1 to 5% by mass.

When the content of the amphiphilic copolymer is in the above range, a composition capable of forming the coating film having more flexibility and excellent touch can be obtained.

In a preferred embodiment of the present invention, the content of the oil agent is 1% by mass or less.

In this way, a composition capable of forming the coating film with less stickiness can be obtained.

In a preferred embodiment of the present invention, the amphiphilic copolymer includes one or two or more copolymers selected from the following group E.

Group E: polyquaternium-51, polyquaternium-61, glyceryl amidoethyl methacrylate/stearyl methacrylate copolymer, and acrylic amphiphilic copolymer comprising structural unit (i) derived from hydrophobic monomer selected from the group consisting of the above-mentioned general formulae (1), (7) and (8)

The composition of the present invention containing such an amphiphilic copolymer can form the coating film having a stronger emulsion-like touch and more excellent flexibility.

In a preferred embodiment of the present invention, the acrylic amphiphilic copolymer comprises a structural unit (j) derived from one or more hydrophilic monomers selected from the following group F.

And F group: a polymerizable carboxylic acid, a copolymer represented by the general formula (2), a copolymer represented by the general formula (9), a copolymer represented by the general formula (10), and a copolymer represented by the general formula (11)

The composition of the present invention containing such an amphiphilic copolymer having a structural unit (j) derived from a hydrophilic monomer can form the coating film having a more excellent feel in an emulsion state and flexibility.

In a preferred embodiment of the present invention, the acrylic amphiphilic copolymer comprises a structural unit (i) derived from the hydrophobic monomer represented by the general formula (1) and a structural unit (j) derived from the hydrophilic monomer represented by the general formula (2).

According to the composition of the present invention comprising such an acrylic amphiphilic copolymer, the coating film having more excellent moisture retention and flexibility can be formed.

The present invention also relates to a coating film having a sea-island structure in which island particles containing an amphiphilic copolymer are dispersed in an aqueous gel comprising a water-soluble polymer, wherein,

the amphiphilic copolymer has one or more structural units (i) derived from a hydrophobic monomer and one or more structural units (j) derived from a hydrophilic monomer as essential structural units.

The coating film of the present invention has a sea-island structure mainly composed of a water-soluble component. Then, the emulsion had a texture similar to that of an emulsion containing an oil agent regardless of the water-soluble component as a main component.

The coating film having such structural characteristics has an excellent feel as an emulsion containing an oil agent.

The present invention also relates to a method for forming the above-described coating film of the present invention, which is characterized by applying an amphiphilic copolymer having one or more structural units (i) derived from a hydrophobic monomer and one or more structural units (j) derived from a hydrophilic monomer as essential structural units, a water-soluble polymer and/or a salt thereof, and water to the skin.

According to the method of the present invention, the coating film can be easily formed.

Also, in a preferred mode of the present invention, the composition contains a polyol which promotes phase separation of the amphipathic copolymer and the aqueous gel and/or a polyol which inhibits phase separation of the aqueous gel and the amphipathic copolymer.

By using an aqueous solution containing such a polyol, a coating film having excellent uniformity can be formed.

Effects of the invention

According to the present invention, a copolymer having an elastic feeling and an external preparation for skin can be provided.

Further, according to the present invention, an emulsion composition which is less irritating to the skin, less sticky and excellent in emulsion stability can be provided.

Also, according to the present invention, a skin cleansing cream with reduced feeling of tightness after use can be provided.

Further, when the present invention is applied to a skin cleansing milk containing a fatty acid soap, favorable foaming and cream-like foam quality are not hindered, and the feeling of tightness after use can be reduced.

Further, even when the present invention is applied to a gel-like skin cleansing milk, the effect of reducing the feeling of tightness after use can be obtained.

Further, according to the present invention, there can be provided an oil-in-water type sunscreen cosmetic composition having an ultraviolet ray protective function, no stickiness, excellent feeling in use such as a moisturizing feeling, and emulsion stability.

Further, according to the present invention, a coating film having a sea-island structure mainly composed of a water-soluble component and a technique for forming the coating film can be provided. The coating film has a touch like an oil-containing emulsion, although it mainly contains a water-soluble component.

In a preferred embodiment of the present invention, a non-adhesive coating and a technique for forming the coating are provided.

Drawings

FIG. 1 is a bar graph showing the evaluation results of gel-like cosmetics comprising the copolymers of example 1 and comparative example 1.

FIG. 2 shows a three-component phase diagram depicting the blending ratio of (glyceryl diisostearate methacrylate/PEG-23 methoxymethacrylate) copolymer, squalane and water in examples 9 to 31.

FIG. 3 is a three-component phase diagram illustrating the mixing ratio of glycerin tris (caprylic/capric) and water in examples 32 to 62.

FIG. 4 shows a three-component phase diagram depicting the compounding ratios of the (diisostearic acid glycerol methacrylate/PEG-23 methoxy methacrylate) copolymer, dimethicone and water in examples 63-89.

FIG. 5 shows a three-component phase diagram of the total amount of 1, 3-butanediol, glycerol, xanthan gum and (PEG-23 methacrylate/glyceryl diisostearate methacrylate) copolymer contained in examples 104 to 124.

Fig. 6 shows a photomicrograph of the composition of examples 105, 106, 108, 111, 113, 114, 115, 119, 120, 122, 123.

Fig. 7 is a pie chart showing the results of tactile evaluation of the composition of example 104 in test example 7.

Detailed Description

The copolymer of the present invention for solving the first problem has one or more structural units (a) derived from the hydrophobic monomer represented by the general formula (1) and one or more structural units (b) derived from the hydrophilic monomer represented by the general formula (2) as essential structural units.

In the present invention, the "structural unit derived from a monomer" refers to a structural unit formed by cleavage of a carbon-carbon unsaturated bond of a corresponding monomer by a polymerization reaction.

The hydrophobic monomer represented by the general formula (1) and the hydrophilic monomer represented by the general formula (2) will be described below.

<1> hydrophobic monomer

The copolymer of the present invention contains, as an essential structural unit, one or two or more structural units derived from the hydrophobic monomer represented by the above general formula (1) (hereinafter, may be simply referred to as "structural unit (1)").

Here, as the alkyl group represented by R1, there can be exemplified: methyl, ethyl, propyl, isopropyl, cyclopropyl, and the like. In the present invention, R1 is preferably a hydrogen atom or a methyl group.

Examples of the acyl group having 6 to 22 carbon atoms, which is not cyclic and has a branched chain, represented by R2 and R3 include: 2-methylpentanoyl, 3-methylpentanoyl, 4-methylpentanoyl, 2-ethylbutanoyl, 2-dimethylbutanoyl, 3-dimethylbutanoyl, 2-methylhexanoyl, 4-methylhexanoyl, 5-methylhexanoyl, 2-dimethylpentanoyl, 4-dimethylpentanoyl, 2-methylheptanoyl, 2-ethylhexyl, 2-propylpentanoyl, 2-dimethylhexanoyl, 2, 3-trimethylpentanoyl, 2-methyloctanoyl, 3, 5-trimethylhexanoyl, 2-methylnonanoyl, 4-methylnonanoyl, 8-methylnonanoyl, 4-ethyloctanoyl, 2-ethyloctanoyl, 2-butylhexanoyl group, 2-tert-butylhexanoyl group, 2-diethylhexanoyl group, 2-dimethyloctanoyl group, 3, 7-dimethyloctanoyl group, neodecanoyl group, 7-methyldecanoyl group, 2-methyl-2-ethyloctanoyl group, 2-methylundecanoyl group, 10-methylundecanoyl group, 2-dimethyldecanoyl group, 2-ethyldecanoyl group, 2-butyloctanoyl group, diethyloctanoyl group, 2-tert-butyl-2, 2, 4-trimethylpentanoyl group, 10-methyldodecanoyl group, 3-methyldodecanoyl group, 4-methyldodecanoyl group, 11-methyldodecanoyl group, 10-ethylundecanoyl group, 12-methylundecanoyl group, 2-butyldecanoyl group, 2-hexyloctanoyl group, 2-butyl-2-ethyloctanoyl group, 12-methyltetradecanoyl group, 14-methylpentadecanoyl group, 2-butyldodecanoyl group, 2-hexyldecanoyl group, 16-methylpentadecanoyl group, 2-dimethylhexanoyl group, 2-butylhexadecanoyl group, 2-hexyldodecanoyl group, 2,4,10, 14-tetramethylpentanoyl group, 18-methylnonadecanoyl group, 3,7,11, 15-tetramethylhexadecanoyl group, 19-methyleicosanoyl group and the like.

In a more preferred embodiment of the present invention, the hydrophobic monomer represented by the general formula (1) is a hydrophobic monomer represented by the general formula (3).

In a preferred embodiment, the acyl group having 10 to 22 carbon atoms, which is represented by R8 and R9 and does not have a ring structure and has a branched chain, includes: 2-methylnonanoyl, 4-methylnonanoyl, 8-methylnonanoyl, 4-ethyloctanoyl, 2-butylhexanoyl, 2-tert-butylhexanoyl, 2-diethylhexanoyl, 2-dimethyloctanoyl, 3, 7-dimethyloctanoyl, neodecanoyl, 7-methyldecanoyl, 2-methyl-2-ethyloctanoyl, 2-methylundecanoyl, 10-methylundecanoyl, 2-dimethyldecanoyl, 2-ethyldecanoyl, 2-butyloctanoyl, diethyloctanoyl, 2-tert-butyl-2, 2, 4-trimethylpentanoyl, 10-methyldodecanoyl, 3-methyldodecanoyl, 4-methyldodecanoyl, 11-methyldodecanoyl, 10-ethylundecanoyl, 12-methyltridecanoyl, 2-butyldecanoyl, 2-hexyloctanoyl, 2-butyl-2-ethyloctanoyl, 12-methyltetradecanoyl, 14-methylpentadecanoyl, 2-butyldodecanoyl, 2-hexyldecanoyl, 16-methylpentadecanoyl, 2-dimethylhexanoyl, 2-butylhexadecanoyl, 2-hexyldodecanoyl, 2,4,10, 14-tetramethylpentanoyl, 18-methylnonadecanoyl, 3,7,11, 15-tetramethylhexadecanoyl, 19-methyleicosanoyl, etc.

In a preferred embodiment, the acyl group having 6 to 9 carbon atoms, which is not cyclic and has 2 or more branches and is represented by R8 or R9, includes: 2, 2-dimethylbutyryl group, 3-dimethylbutyryl group, 2-dimethylpentanoyl group, 4-dimethylpentanoyl group, 2-dimethylhexanoyl group, 2, 3-trimethylpentanoyl group, 3,5, 5-trimethylhexanoyl group and the like.

The acyl group of R8 and R9 in the general formula (3) preferably has 12 to 22 carbon atoms, more preferably 14 to 20 carbon atoms, and still more preferably 16 to 20 carbon atoms.

The main chain of the acyl group of R8 and R9 in the general formula (3) preferably has 9 to 21 carbon atoms, more preferably 12 to 20 carbon atoms, and still more preferably 16 to 18 carbon atoms.

The number of branches in the acyl group of R8 and R9 in the general formula (3) is preferably 1 to 3, more preferably 1 or 2, and still more preferably 1.

In the acyl group of R8 or R9 in the general formula (3), the number of positions of the carbon of the main chain to which the branch is bonded is preferably as large as possible. Specifically, the branched chain is preferably bonded to 1 to 3 carbons, more preferably 1 or 2 carbons, and still more preferably 1 carbon among carbons at the end of the main chain.

As R8 and R9, specifically, preferred examples can be given: 10-methylundecanoyl, 10-methyldodecanoyl, 11-methyldodecanoyl, 10-ethylundecanoyl, 12-methylundecanoyl, 12-methyltetradecanoyl, 14-methylpentaneoyl, 16-methylpentaneoyl, 2,4,10, 14-tetramethylpentanoyl, 18-methylnonadecanoyl, 3,7,11, 15-tetramethylhexadecanoyl, 19-methyleicosanoyl, etc.

The group derived from a triol represented by X or Y in the general formulae (1) and (3) is not particularly limited as long as it is a group in which an OH group is separated from a triol, and a group in which an OH group is separated from a triol selected from the group consisting of glycerin, trimethylolpropane and trimethylolethane is preferable.

In a preferred embodiment of the present invention, a monomer represented by the above general formula (5) is preferably used as the hydrophobic monomer.

Examples of the hydrophobic monomer represented by the general formula (5) include compounds represented by the following formulae (12) to (14). It is preferable to use a compound represented by the following formula (12) in which a branch is attached to the terminal of the acyl group.

[ chemical formula 12]

[ chemical formula 13]

[ chemical formula 14]

The hydrophobic monomer represented by the general formula (1) constituting the copolymer of the present invention can be synthesized, for example, by the following method.

a) And (3) ketalizing the trihydric alcohol. As a specific synthesis method, for example, the method described in production example 1 of jp 2009-.

b) Synthesizing a (meth) acrylate ester of a ketal by transesterification of the ketal-formed triol synthesized in a) with an alkyl (meth) acrylate, and conducting a de-ketonization reaction of the obtained (meth) acrylate ester of a ketal to synthesize a mono (meth) acrylate ester of a triol. As a specific synthesis method, for example, the method described in example 1 of japanese patent application laid-open No. 2004-18389 can be exemplified.

c) Reacting the mono (meth) acrylate of the triol obtained in b) with a carboxylic acid having a predetermined branched structure or an anhydride thereof or a chloride thereof to obtain a hydrophobic monomer represented by the general formula (1).

Since commercially available products are also present in the ketalized trihydric alcohols, the esters of the trihydric alcohols of the invention can also be obtained by the above-mentioned steps b) and c) using such commercially available products. Examples of such commercially available products include (S) - (+) -2, 2-dimethyl-1, 3-dioxolane-4-methanol and (R) - (+) -2, 2-dimethyl-1, 3-dioxolane-4-methanol (both produced by tokyo chemical industry co.). Furthermore, since the mono (meth) acrylate of a triol is also commercially available, the ester of a triol of the present invention can be obtained by the above step c) using such a commercially available product. An example of such a commercially available product is "BLEMMER GLM" (glycerol monomethacrylate, manufactured by japan fat and oil corporation).

The proportion of the structural unit (a) in the copolymer of the present invention to the total structural units is preferably 1 to 40% by mass, more preferably 5 to 35% by mass.

By setting the ratio of the structural unit (a) in the above range, the elasticity of the copolymer of the present invention can be improved.

<2> hydrophilic monomer

The copolymer of the present invention contains one or more kinds of structural units derived from the hydrophilic monomer represented by the general formula (2) as essential structural units.

As the alkyl group represented by R4 in the general formula (2), there can be exemplified: methyl, ethyl, propyl, isopropyl, cyclopropyl. In the present invention, R4 is preferably a hydrogen atom or a methyl group.

Further, as the alkylene group represented by R5, there can be exemplified: vinyl, propenyl, isopropenyl, 2-hydroxypropenyl, 1-hydroxy-2-methylethenyl, 2-hydroxy-1-methylethenyl and the like, of which vinyl or propenyl is preferred, and vinyl is more preferred.

Examples of the aromatic group having 6 to 10 carbon atoms in the group represented by R6 include: phenyl, benzyl, methylphenyl, ethylphenyl, and the like; preferred examples of the aliphatic hydrocarbon group having 1 to 14 carbon atoms include: methyl, ethyl, butyl, t-butyl, hexyl, cyclohexyl, octyl, 2-ethylhexyl, lauryl, and the like; preferred examples of the acyl group having 1 to 12 carbon atoms include: formyl, acetyl, propionyl, butyryl, isobutyryl, valeryl, lauroyl and the like. Among them, the group represented by R5 is preferably an aliphatic hydrocarbon group having 1 to 14 carbon atoms, and more preferably an alkyl group having 1 to 12 carbon atoms.

In the general formula (2), n is in a numerical range of 6 to 40.

Among the monomers represented by the general formula (2), the monomer wherein R5 is an acryl group includes, specifically: polypropylene glycol (9) monoacrylate, polypropylene glycol (13) monoacrylate, polypropylene glycol (9) monomethacrylate, polypropylene glycol (13) monomethacrylate, and the like. In addition, the number in parentheses represents N. Many of these polymers are available as commercial products. Specific examples of such commercially available products include those sold under the trade names "BLEMMER" AP-400, AP-550, AP-800, PP-500 and PP-800 (all manufactured by Nippon fat and oil Co., Ltd.).

Among the monomers represented by the general formula (2), the monomers wherein R5 is a vinyl group include, specifically: polyethylene glycol (10) monoacrylate, polyethylene glycol (8) monomethacrylate, polyethylene glycol (23) monoacrylate, polyethylene glycol (23) monomethacrylate, methoxypolyethylene glycol (9) acrylate, methoxypolyethylene glycol (9) methacrylate, methoxypolyethylene glycol (23) methacrylate, oleoyloxy polyethylene glycol (18) methacrylate, lauroyl polyethylene glycol (18) acrylate, lauroyloxy polyethylene glycol (10) methacrylate, stearoyloxy polyethylene glycol (30) monomethacrylate, and the like.

In a preferred embodiment of the present invention, a monomer represented by the general formula (6) is used as the hydrophilic monomer.

L in the general formula (6) is preferably 6-30, and more preferably 8-30.

The above hydrophilic monomers can be obtained in high yield by esterification of the corresponding polyethylene glycol, polyethylene glycol monoether, polyethylene glycol monoester and chloride or anhydride of acrylic acid or methacrylic acid. Since a large number of commercially available products are already available, such commercially available products can also be used. Specific examples of such commercially available products include trade names such as "BLEMMER" AE-400, PE-350, AME-400, PME-1000, ALE-800 and PSE-1300 (all manufactured by Nippon fat and oil Co., Ltd.).

The structural unit derived from the hydrophilic monomer contained in the copolymer of the present invention may be only one type, but may be a combination of two or more types as long as the above conditions are satisfied.

The proportion of the structural unit (b) derived from the hydrophilic monomer in the copolymer of the present invention is 30 to 95% by mass, preferably 40 to 90% by mass, based on the total constituent units.

By setting the proportion of the structural unit (b) in the above range, the elastic feeling of the copolymer of the present invention can be improved.

<3> other optional structural units

Examples of such arbitrary structural units include structural units derived from a monomer generally used in the copolymer, such as (meth) acrylamide such as acrylamide, methacrylamide, monoalkylamide acrylate, monoalkylamide methacrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-dodecyl methacrylate, stearyl (meth) acrylate, alkyl (meth) acrylate such as isostearyl (meth) acrylate, cycloalkyl (meth) acrylate such as cyclohexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, hydroxyalkyl (meth) acrylate such as hydroxyalkyl (meth) acrylate, aryl (meth) acrylate such as benzyl (meth) acrylate, methoxymethyl (meth) acrylate, methoxyethyl (meth) acrylate, styrene-acrylic acid, acrylonitrile, and styrene-acrylic acid vinyl acetate, α -acrylonitrile, all of which are commercially available.

<4> copolymer of the present invention

The copolymer of the present invention is a copolymer containing a structural unit (a) and a structural unit (b) in its skeleton. The copolymer of the present invention is usually a random copolymer in which the structural units are randomly bonded, but may be a block copolymer or a graft copolymer.

The copolymer of the present invention is characterized in that the weight average molecular weight is 20000 to 110000. By setting the weight average molecular weight to the above range, the copolymer of the present invention is a copolymer having an elastic feeling.

The weight average molecular weight of the copolymer of the present invention is more preferably 20000 to 80000, more preferably 30000 to 80000, more preferably 40000 to 70000, further preferably 50000 to 70000, and further preferably 57000 to 66000.

Here, the weight average molecular weight means a weight average molecular weight in terms of polystyrene measured by GPC.

The method for producing the copolymer of the present invention is not particularly limited, and the copolymer can be obtained by the following method: for example, monomers derived from each structural unit are mixed in a solvent, and polymerization is carried out according to a method generally used for polymerization of an acrylic monomer.

Here, the weight average molecular weight of the copolymer can be adjusted by changing the reaction time or reaction temperature of the polymerization reaction. Specifically, by shortening the reaction time, the weight average molecular weight can be reduced.

The copolymer of the present invention is preferably water-soluble because it can be easily handled at the time of use. The term "copolymer" as used herein is defined as a copolymer having a transmittance of 90% or more in a 20 wt% aqueous solution of the copolymer at 25 ℃. In order to obtain such a polymer, such a polymerization method is particularly preferable among the above polymerization methods, that is: the monomer mixture is subjected to radical polymerization in a mixed solvent of an aqueous solution and an aqueous solvent mixed with water at 25 ℃ in an arbitrary ratio. Further, since the amount of residual monomers after the polymerization reaction is small, a polymerization method using a buffer solution instead of water is more preferable. The aqueous solution having a buffering action used in this method is not particularly limited as long as it is a buffer solution that is generally used, and specifically, there can be exemplified: potassium chloride-hydrochloric acid solution, potassium dihydrogen phosphate-disodium hydrogen phosphate solution, potassium hydrogen citrate-citric acid solution, sodium carbonate-sodium bicarbonate solution, and the like. Further, a salt, an acid or an alkali aqueous solution that forms a buffer solution with ions of the initiator may be used, and the buffer solution may be formed at the time of adding the initiator. Further, as the aqueous solvent to be mixed with water at 25 ℃ in an arbitrary ratio used in this method, specifically, there can be exemplified: alcohols having 1 to 3 carbon atoms such as methanol, ethanol, n-propanol and isopropanol, ketones such as acetone and methyl ethyl ketone, glycols such as ethylene glycol, polyethylene glycol, propylene glycol and 1, 3-butanediol, ethylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether, and tetrahydrofuran. Among these aqueous solvents, alcohols having 1 to 3 carbon atoms such as methanol, ethanol, n-propanol, and isopropanol are particularly preferable because they are easily polymerized.

In the present invention, the mass ratio of the structural unit (a) to the structural unit (b) constituting the copolymer is preferably 5:95 to 50:50, more preferably 10:90 to 45:55, still more preferably 20:80 to 40:60, and still more preferably 25:75 to 35: 65.

The molar ratio of the structural unit (a) to the structural unit (b) constituting the copolymer is preferably 8:92 to 62:38, more preferably 15:85 to 57:43, still more preferably 29:71 to 52:48, and still more preferably 35:65 to 46: 54.

By setting the mass ratio and the molar ratio of the structural unit (a) to the structural unit (b) in the copolymer to the above ranges, the elastic feeling can be further improved.

<5> external preparation for skin comprising copolymer of the present invention

The skin external preparation containing the copolymer of the present invention has an elastic feeling and is less likely to cause stickiness.

The content of the copolymer of the present invention in the skin external preparation is preferably 0.5 to 30% by mass, and more preferably 1 to 25% by mass.

The skin preparation for external use of the present invention may preferably be exemplified by external drugs such as ointments, cosmetics, and the like. Further, as the cosmetic, there can be exemplified: cream, lotion, toner, beauty lotion, skin care products such as sunscreen cosmetics, makeup bases, foundation, eye shadow, cosmetics such as mascara, skin cleansers such as face toilet, hair cosmetics such as shampoo, hair spray, hair gel, etc.

The external skin preparation of the present invention may contain, as optional components, those usually used in external skin preparations within the range not impairing the effects of the present invention, specifically, those such as macadamia nut oil, avocado oil, corn oil, olive oil, rapeseed oil, sesame oil, castor oil, safflower oil, cottonseed oil, jojoba oil, coconut oil, liquid lanolin, hardened coconut oil, hardened oil, cutleran wax, hydrogenated castor oil, beeswax, candelilla wax, carnauba wax, rock wax, lanolin, reduced lanolin, hard lanolin, jojoba wax, fluid paraffin, squalane, pristane, ceresin, paraffin, white wax, vaseline, microcrystalline wax, hydrocarbon such as oleic acid, isostearic acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, undecylenic acid, higher fatty acid such as cetyl alcohol, stearyl alcohol, isostearyl alcohol, lauryl alcohol, myristyl alcohol, cetyl stearyl alcohol, cetyl alcohol, stearyl alcohol, cetyl alcohol, polyoxyethylene lauryl alcohol, sorbitan fatty acid, polyoxyethylene lauryl alcohol, polyoxyethylene sorbitan fatty acid, polyoxyethylene glycol, polyoxyethylene sorbitan fatty acid, polyoxyethylene ether, polyoxyethylene sorbitan fatty acid, polyoxyethylene glycol, polyoxyethylene ether, polyoxyethylene sorbitan fatty acid, polyoxyethylene ether, polyoxyethylene sorbitan fatty acid, polyoxyethylene ether, polyoxyethylene sorbitan fatty acid, polyoxyethylene ether, polyoxyethylene sorbitan fatty acid, polyoxyethylene ether, polyoxyethylene sorbitan fatty acid, polyoxyethylene ether, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid, polyoxyethylene ether, polyoxyethylene sorbitan fatty acid, polyoxyethylene ether, polyoxyethylene ether, polyoxyethylene sorbitan fatty acid, polyoxyethylene ether, polyoxyethylene sorbitan fatty acid, polyoxyethylene ether, polyoxyethylene sorbitan fatty acid, polyoxyethylene ether, polyoxyethylene sorbitan fatty acid, polyoxyethylene ether, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid, polyoxyethylene ether, polyoxyethylene sorbitan fatty acid, polyoxyethylene ether, polyoxyethylene sorbitan fatty acid, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid, polyoxyethylene ether, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid, polyoxyethylene ether, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene ether, polyoxyethylene sorbitan fatty acid, polyoxyethylene ether, polyoxyethylene ether, polyoxyethylene sorbitan fatty acid, polyoxyethylene ether, polyoxyethylene sorbitan fatty acid, polyoxyethylene ether, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene ether.

The external preparation for skin of the present invention can be prepared by treating the above-mentioned essential ingredients and optional ingredients using a conventional method.

The emulsion composition of the present invention for solving the second problem is characterized by containing a water-soluble copolymer having a structural unit (c) derived from a hydrophobic monomer and a structural unit (d) derived from a hydrophilic monomer. Hereinafter, the water-soluble copolymer, which is a copolymer of a hydrophobic monomer, a hydrophilic monomer, and a copolymer thereof, will be described in the item <1 >.

<1> Water-soluble copolymer

[ 1] hydrophobic monomer

In the present invention, a water-soluble copolymer containing, as an essential structural unit, one or two or more structural units derived from the hydrophobic monomer represented by the above general formula (1), (7) or (8) (hereinafter, may be simply referred to as "structural unit (7) or the like") is used.

In the present invention, the "structural unit derived from a monomer" refers to a structural unit formed by cleavage of a carbon-carbon unsaturated bond of the corresponding monomer by a polymerization reaction.

The hydrophobic monomer represented by the general formula (1), (7) or (8) will be described below.

(1-1) hydrophobic monomer represented by the general formula (7)

In the general formula (7), R14 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R15 represents a branched hydrocarbon group having 13 to 30 carbon atoms and no ring structure, or a hydrocarbon group having 2 or more branches and having 6 to 12 carbon atoms and no ring structure.

Here, as the alkyl group represented by R14, there can be exemplified: methyl, ethyl, propyl, isopropyl, cyclopropyl, and the like. In the present invention, R14 is preferably a hydrogen atom or a methyl group.

Examples of the branched hydrocarbon group having 13 to 30 carbon atoms and not having a ring structure represented by R15 include: 1-methyldodecyl, 11-methyldodecyl, 3-ethylundecyl, 3-ethyl-4, 5, 6-trimethyloctyl, 1-methylundecyl, 1-hexyloctyl, 2-butylundecyl, 2-hexyloctyl, 4-ethyl-1-isooctyl, 1-methylpentadecyl, 2-hexylundecyl group, 2-octylundecyl group, 2-hexyldodecyl group, 16-methylpentadecyl group, 9-methylpentadecyl group, 7-methyl-2- (3-methylhexyl) decyl group, 3,7,11, 15-tetramethylhexadecyl group, 2-octyldodecyl group, 2-decyltetradecyl group, 2-dodecylhexadecyl group and the like.

Examples of the hydrocarbon group of 6 to 12 carbon atoms having 2 or more branches and not containing a ring structure represented by R15 include: 2, 2-dimethylbutyl, 2, 3-dimethylbutyl, 3-dimethylbutyl, 1,2, 2-trimethylpropyl, 1-dimethylpentyl, 1-isopropylbutyl, 1-isopropyl-2-methylpropyl, 1-diethylpropyl, 1-ethyl-1-isopropylpropyl, 2-ethyl-4-methylpentyl, 1-propyl-2, 2-dimethylpropyl, 1, 2-trimethylpentyl, 1-isopropyl-3-methylbutyl, 1, 2-dimethyl-1-ethylbutyl, 1, 3-dimethyl-1-ethylbutyl, 1-ethyl-1-isopropylpropyl, 1, 3-dimethyl-1-isopropylbutyl, 1, 1-dimethylhexyl, 1-methyl-1-ethylpentyl, 1-methyl-1-propylbutyl, 1, 4-dimethylhexyl, 1-ethyl-3-methylpentyl, 1, 5-dimethylhexyl, 1-ethyl-6-methylheptyl, 1,3, 3-tetramethylbutyl, 1, 2-dimethyl-1-isopropylpropyl, 3-methyl-1- (2, 2-dimethylethyl) butyl, 1-isopropylhexyl, 3, 5-trimethylhexyl, 2-isopropyl-5-methylhexyl, 1, 5-dimethyl-1-ethylhexyl, 3, 7-dimethyloctyl, 2,4, 5-trimethylheptyl, 2,4, 5-trimethylhexyl, 1, 4-dimethylheptyl, 1, 4-dimethylhexyl, 3, 2-dimethylhexyl, 1, 2-ethylhexyl, 3-dimethylhexyl, 2-ethyl, 2,4, 6-trimethylheptyl, 3, 5-dimethyl-1- (2, 2-dimethylethyl) hexyl and the like.

(1-2) hydrophobic monomer represented by the general formula (1) or (8)

In the general formulae (1) and (8), R1 and R16 each represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R2, R3, R17, R18 and R19 may be the same or different and each represent an acyl group having 6 to 22 carbon atoms, which is branched and does not contain a ring structure. X represents a group obtained by removing an OH group from a triol.

Here, examples of the alkyl group represented by R1 and R16 include: methyl, ethyl, propyl, isopropyl, cyclopropyl, and the like. In the present invention, R1 is preferably a hydrogen atom or a methyl group.

Examples of the acyl group having 6 to 22 carbon atoms, which is not a ring structure, and which is branched and is represented by R2, R3, R17, R18, and R19, include: 2-methylpentanoyl, 3-methylpentanoyl, 4-methylpentanoyl, 2-ethylbutanoyl, 2-dimethylbutanoyl, 3-dimethylbutanoyl, 2-methylhexanoyl, 4-methylhexanoyl, 5-methylhexanoyl, 2-dimethylpentanoyl, 4-dimethylpentanoyl, 2-methylheptanoyl, 2-ethylhexyl, 2-propylpentanoyl, 2-dimethylhexanoyl, 2, 3-trimethylpentanoyl, 2-methyloctanoyl, 3, 5-trimethylhexanoyl, 2-methylnonanoyl, 4-methylnonanoyl, 8-methylnonanoyl, 4-ethyloctanoyl, 2-ethyloctanoyl, 2-butylhexanoyl, 2-tert-butylhexanoyl, 2-diethylhexanoyl, 2-dimethyloctanoyl, 3, 7-dimethyloctanoyl, neodecanoyl, 7-methyldecanoyl, 2-methyl-2-ethyloctanoyl, 2-methylundecanoyl, 10-methylundecanoyl, 2-dimethyldecanoyl, 2-ethyldecanoyl, 2-butyloctanoyl, diethyloctanoyl, 2-tert-butyl-2, 2, 4-trimethylpentanoyl, 10-methyldodecanoyl, 3-methyldodecanoyl, 4-methyldodecanoyl, 11-methyldodecanoyl, 10-ethylundecanoyl, 12-methyltridecanoyl, 2-butyldecanoyl, 2-hexyloctanoyl group, 2-butyl-2-ethyloctanoyl group, 12-methyltetradecanoyl group, 14-methylpentadecanoyl group, 2-butyldodecanoyl group, 2-hexyldecanoyl group, 16-methylheptadecanoyl group, 2, 2-dimethylhexanoyl group, 2-butylhexadecanoyl group, 2-hexyldodecanoyl group, 2,4,10, 14-tetramethylpentanoyl group, 18-methylnonadecanoyl group, 3,7,11, 15-tetramethylhexadecanoyl group, 19-methyleicosanoyl group and the like.

In a preferred embodiment of the present invention, in the general formulae (1) and (8), R2, R3, R17, R18 and R19 may be the same or different and are each an acyl group having 10 to 22 carbon atoms and having a branch chain and not having a ring structure, or an acyl group having 6 to 9 carbon atoms and not having 2 or more branches.

Examples of the acyl group having 10 to 22 carbon atoms and a branched chain, which is not a ring structure, represented by R2, R3, R17, R18 and R19 in the preferred embodiment include: 2-methylnonanoyl, 4-methylnonanoyl, 8-methylnonanoyl, 4-ethyloctanoyl, 2-butylhexanoyl, 2-tert-butylhexanoyl, 2-diethylhexanoyl, 2-dimethyloctanoyl, 3, 7-dimethyloctanoyl, neodecanoyl, 7-methyldecanoyl, 2-methyl-2-ethyloctanoyl, 2-methylundecanoyl, 10-methylundecanoyl, 2-dimethyldecanoyl, 2-ethyldecanoyl, 2-butyloctanoyl, diethyloctanoyl, 2-tert-butyl-2, 2, 4-trimethylpentanoyl, 10-methyldodecanoyl, 3-methyldodecanoyl, 4-methyldodecanoyl, 11-methyldodecanoyl, 10-ethylundecanoyl, 12-methyltridecanoyl, 2-butyldecanoyl, 2-hexyloctanoyl, 2-butyl-2-ethyloctanoyl, 12-methyltetradecanoyl, 14-methylpentadecanoyl, 2-butyldodecanoyl, 2-hexyldecanoyl, 16-methylheptanoyl, 2-dimethylhexanoyl, 2-butylhexadecanoyl, 2-hexyldodecanoyl, 2,4,10, 14-tetramethylpentanoyl, 18-methylnonadecanoyl, 3,7,11, 15-tetramethylhexadecanoyl, 19-methyldicosanoyl and the like.

In a preferred embodiment, the acyl group having 6 to 9 carbon atoms, which is not cyclic and has 2 or more branches, represented by R2, R3, R17, R18 and R19, includes: 2, 2-dimethylbutyryl group, 3-dimethylbutyryl group, 2-dimethylpentanoyl group, 4-dimethylpentanoyl group, 2-dimethylhexanoyl group, 2, 3-trimethylpentanoyl group, 3,5, 5-trimethylhexanoyl group and the like.

The group derived from a triol represented by X in the general formula (1) is not particularly limited as long as it is a group in which an OH group is removed from a triol, and a group in which an OH group is removed from a triol selected from the group consisting of glycerin, trimethylolpropane and trimethylolethane is preferably exemplified.

The group derived from a tetraol represented by Y in the general formula (8) is not particularly limited as long as it is a group in which an OH group is removed from a tetraol, and preferable examples thereof include a group in which an OH group is removed from a tetraol selected from the group consisting of diglycerin, pentaerythritol, erythritol, D-threitol, and L-threitol.

In the present invention, a water-soluble copolymer comprising the structural unit (1) is particularly preferably used.

In a more preferred embodiment of the present invention, the hydrophobic monomer represented by the general formula (1) is a hydrophobic monomer represented by the following general formula (15).

General formula (15)

[ chemical formula 15]

(in the general formula (15), R24 and R25 may be the same or different and each represents an acyl group having 16 to 22 carbon atoms and containing no cyclic structure and having a branched chain, and Z represents a group obtained by removing an OH group from a triol.)

The acyl group of R24 and R25 in the general formula (15) has 12 to 22 carbon atoms, more preferably 14 to 20 carbon atoms, and still more preferably 16 to 20 carbon atoms.

The main chain of the acyl group of R24 and R25 in the general formula (15) preferably has 9 to 21 carbon atoms, more preferably 12 to 20 carbon atoms, and still more preferably 16 to 18 carbon atoms.

The number of branches in the acyl group of R24 and R25 in the general formula (15) is preferably 1 to 3, more preferably 1 or 2, and still more preferably 1.

In the acyl group of R24 or R25 in the general formula (15), the number of positions of the carbon of the main chain to which the branch is bonded is preferably as large as possible. Specifically, the branched chain is preferably bonded to 1 to 3 carbon atoms, more preferably 1 or 2 carbon atoms, and still more preferably 1 carbon atom, among the carbon atoms at the end of the main chain.

As R24 and R25, specifically, preferred examples can be given: 10-methylundecanoyl, 10-methyldodecanoyl, 11-methyldodecanoyl, 10-ethylundecanoyl, 12-methyltridecanoyl, 12-methyltetradecanoyl, 14-methylpentaneoyl, 16-methylpentaneoyl, 2,4,10, 14-tetramethylpentanoyl, 18-methylnonadecanoyl, 3,7,11, 15-tetramethylhexadecanoyl, 19-methyleicosanoyl, and the like.

The group derived from a triol represented by Z in the general formula (15) is not particularly limited as long as it is a group in which an OH group is removed from a triol, and a group in which an OH group is removed from a triol selected from the group consisting of glycerin, trimethylolpropane and trimethylolethane is preferably exemplified.

[ 2] hydrophilic monomer

As the hydrophilic monomer in the present invention, a polymerizable carboxylic acid, and compounds represented by the general formula (2), the general formulae (9), (10), and (11) can be used.

(2-1) polymerizable carboxylic acid

In the present invention, as the polymerizable carboxylic acid or a salt thereof, specifically, there can be exemplified: acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, and sodium, potassium, ammonium, amine salts thereof, and the like. Among them, acrylic acid, methacrylic acid and salts thereof are particularly preferable because of high polymerizability. When a structural unit derived from a salt of a polymerizable carboxylic acid is introduced into the water-soluble copolymer of the present invention, the polymerizable carboxylic acid may be previously formed into a salt and subjected to a polymerization reaction, or a structural unit derived from a polymerizable carboxylic acid may be introduced into the water-soluble copolymer by a polymerization reaction and then neutralized with an alkali to form a salt.

(2-2) hydrophilic monomer represented by the general formula (2)

In the general formula (2), R4 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R5 represents an alkylene group having 2 to 4 carbon atoms which may have a hydroxyl group, and R6 represents a hydrogen atom, an aromatic hydrocarbon group having 6 to 10 carbon atoms, an aliphatic hydrocarbon group having 1 to 14 carbon atoms, or an acyl group having 1 to 12 carbon atoms. n represents an integer of 6 to 40.

Further, as the alkylene group represented by R5, there can be exemplified: vinyl, propenyl, isopropenyl, 2-hydroxypropenyl, 1-hydroxy-2-methylethenyl, 2-hydroxy-1-methylethenyl and the like, among which vinyl or propenyl is preferred, and vinyl is more preferred.

Examples of the aromatic group having 6 to 10 carbon atoms in the group represented by R6 include: phenyl, benzyl, methylphenyl, ethylphenyl, and the like; examples of the aliphatic hydrocarbon group having 1 to 14 carbon atoms include: methyl, ethyl, butyl, t-butyl, hexyl, cyclohexyl, octyl, 2-ethylhexyl, lauryl, and the like; examples of the acyl group having 1 to 12 carbon atoms include: formyl, acetyl, propionyl, butyryl, isobutyryl, valeryl, lauroyl and the like. Among them, the group represented by R5 is preferably an aliphatic hydrocarbon group having 1 to 14 carbon atoms, and more preferably an alkyl group having 1 to 12 carbon atoms.

In the general formula (2), n is in a numerical range of 6 to 40.

Among the monomers represented by the general formula (2), the monomer wherein R5 is an acryl group includes: polypropylene glycol (9) monoacrylate, polypropylene glycol (13) monoacrylate, polypropylene glycol (9) monomethacrylate, polypropylene glycol (13) monomethacrylate, and the like. In addition, the number in parentheses represents N. Many of these polymers are available as commercial products. Specific examples of such commercially available products include those sold under the trade names "BLEMMER" AP-400, AP-550, AP-800, PP-500 and PP-800 (all manufactured by Nippon fat and oil Co., Ltd.).

Among the monomers represented by the above general formula (2), the monomers wherein R5 is a vinyl group include, specifically: polyethylene glycol (10) monoacrylate, polyethylene glycol (8) monomethacrylate, polyethylene glycol (23) monoacrylate, polyethylene glycol (23) monomethacrylate, methoxypolyethylene glycol (9) acrylate, methoxypolyethylene glycol (9) methacrylate, methoxypolyethylene glycol (23) methacrylate, vinyl polyethylene glycol (18) methacrylate, lauroyl polyethylene glycol (18) acrylate, lauroyloxypolyethylene glycol (10) methacrylate, stearoyloxypolyethylene glycol (30) monomethacrylate, and the like.

(2-3) hydrophilic monomer represented by the general formula (9)

As the hydrophilic monomer in the present invention, a hydrophilic monomer represented by the above general formula (9) can be used.

Specific examples of the hydrophilic monomer represented by the general formula (9) include: 2-Acryloyloxyethylphosphorylcholine (APC), 2-Methacryloyloxyethylphosphorylcholine (MPC). These monomers can be synthesized by the following method, for example, as described in PolymerJournal, vol.22, No. 5.

< Synthesis method >

2-bromoethylphosphoryl dichloride is reacted with 2-hydroxyethyl methacrylate or 2-hydroxyethyl acrylate to give 2-methacryloyloxyethyl-2 '-bromoethyl phosphate or 2-acryloyloxyethyl-2' -bromoethyl phosphate, after which these compounds are reacted with triethylamine in methanol.

(2-4) hydrophilic monomer represented by the general formula (10)

As the hydrophilic monomer in the present invention, a hydrophilic monomer represented by the above general formula (10) can be used.

Among the hydrophilic monomers represented by the general formula (10), reducing sugars as a group obtained by removing hydrogen from a hydroxyl group at position 1 of the reducing sugar represented by G-O-, specifically, one or two or more selected from the group consisting of: monosaccharides such as glucose, mannose, galactose, arabinose, xylose, and ribose, maltose, lactose, disaccharides such as cellobiose, trisaccharides such as maltotriose, and oligosaccharides such as maltooligosaccharides, and among these, one or two or more selected from the group consisting of: glucose, galactose, arabinose, xylose, ribose, maltose, lactose, cellobiose, and particularly preferably glucose. Also, as the monomer represented by the general formula (10), glycosyloxyethyl methacrylate (hereinafter, abbreviated as GEMA) or glycosyloxyethyl acrylate (hereinafter, abbreviated as GEA) is preferable.

(2-5) hydrophilic monomer represented by the general formula (11)

As the hydrophilic monomer in the present invention, a hydrophilic monomer represented by the above general formula (11) can be used.

In the monomer of the general formula (11), the amino acid as the amino acid residue represented by R23 is not particularly limited as long as it is a known amino acid, and specifically, it may be exemplified by: glycine, alanine, glutamine, lysine, arginine, and the like. Among these, lysine residue is particularly preferable because the obtained water-soluble copolymer is excellent in the skin barrier recovery effect.

The polyamine in the polyamine residue represented by R23 is an amine having two or more amino groups that may be substituted with an alkyl group in the same molecule, and specifically, it can be exemplified by: diamines, triamines, tetramines or amines in which the hydrogen atoms of the amino groups have been replaced by alkyl groups. Among them, diamines are preferable because the use feeling of the skin external preparation containing the obtained water-soluble copolymer is particularly excellent, and specific examples of the diamines are particularly preferable because raw materials are easily available at the time of synthesis, and thus, the following are listed: ethylenediamine, 1, 4-diamino-n-butane, 1, 6-diamino-n-hexane, and the like.

The amino alcohol in the amino alcohol residue represented by R23 is a compound having an amino group which may be substituted with an alkyl group in the same molecule and an alcoholic hydroxyl group. The aminoalcohol is not particularly limited as long as it is known, and specific examples thereof include ethanolamine, triethylaminoethanol, and the like.

The salt of the monomer represented by the general formula (11) is not particularly limited, and specifically, there may be exemplified: sodium salt, potassium salt, ammonium salt, amine salt, etc. obtained by neutralizing an acid moiety with an alkali, and hydrochloride, sulfate, nitrate, phosphate, citrate, oxalate, carbonate, etc. obtained by neutralizing an amino moiety with an acid. When the structural unit derived from the salt of the monomer represented by the general formula (11) is introduced into the water-soluble copolymer of the present invention, the monomer represented by the general formula (11) may be previously formed into a salt to be polymerized, or the structural unit derived from the monomer represented by the general formula (11) may be derived from the water-soluble copolymer by polymerization and then neutralized to form a salt.

As specific examples of the monomer represented by the general formula (11) and salts thereof, compounds 1 to 11 having the following structures and salts thereof can be preferably exemplified.

Compound 1

[ chemical formula 16]

Compound 2[ chemical formula 17]

Compound 3[ chemical formula 18]

Compound 4[ chemical formula 19]

Compound 5[ chemical formula 20]

Compound 6[ chemical formula 21]

Compound 7[ chemical formula 22]

Compound 8[ chemical formula 23]

Compound 9[ chemical formula 24]

Compound 10[ chemical formula 25]

Compound 11

[ chemical formula 26]

The hydrophilic monomer represented by the general formula (11) can be synthesized, for example, by an esterification reaction or an amidation reaction using (meth) acrylic acid or (meth) acryloyl chloride as shown in the following reaction formulas (1) and (2).

Reaction formula (1)

[ chemical formula 27]

Reaction type (2)

[ chemical formula 28]

(in the reaction formula, R22 represents a hydrogen atom or a methyl group, R23 represents an amino acid residue, a polyamine residue or an amino alcohol residue, Q represents an oxygen atom or a group represented by NH.)

As described above, in the present invention, the hydrophilic polymer can be used by the general formula (2), the general formula (9), the general formula (10), and the general formula (11).

In a preferred embodiment of the present invention, the water-soluble copolymer comprises a structural unit (2) derived from said general formula (2).

[ 3] Water-soluble copolymer

In the present invention, a water-soluble copolymer having the structural unit (1) and the structural unit (2) is preferably used. Further, a water-soluble copolymer having the structural unit (15) and the structural unit (2) is more preferably used.

Among such water-soluble copolymers, the copolymer (PEG-23 methoxy methacrylate/glyceryl diisostearate methacrylate (/ ジイソステアリン acid メタクリル acid グリセリル)) is particularly preferably used.

By containing such a water-soluble copolymer, an emulsion composition having low irritation, low viscosity, and excellent emulsion stability can be obtained.

The (PEG-23 methoxymethacrylate/diisostearic acid glyceryl methacrylate) copolymer mainly contains, as the structural unit (c), a structural unit (c) derived from a hydrophobic monomer in which R24 and R25 are 16-methylpentadecanoyl groups among the hydrophobic monomers represented by the general formula (15).

And a structural unit (d) derived mainly from a hydrophilic monomer represented by the general formula (2) wherein R4 is a methyl group, R5 is a vinyl group, R6 is a methyl group, and n is 23.

In general, a surfactant having high hydrophobicity is suitable for the formation of a water-in-oil type emulsion composition, whereas a surfactant having high hydrophilicity is suitable for the formation of an oil-in-water type emulsion composition. Similarly, the water-soluble copolymer of the present invention is suitable for forming a water-in-oil emulsion composition when the proportion of the hydrophobic structural unit (c) is high, and is suitable for forming an oil-in-water emulsion composition when the proportion of the hydrophilic structural unit (d) is high.

Thus, the emulsification system of the emulsion composition to be formed can be adjusted by appropriately adjusting the ratio and the ratio of the structural unit (c) and the structural unit (d).

In the present invention, the proportion of the structural unit (c) in the water-soluble copolymer to the total structural units is preferably 1 to 50% by mass, more preferably 20 to 50% by mass, and even more preferably 30 to 40% by mass.

By setting the proportion of the structural unit (c) in the water-soluble copolymer in the above range, an oil-in-water emulsion composition having a further reduced sticky feeling can be provided.

In the present invention, the proportion of the structural unit (d) in the water-soluble copolymer in the total structural units is preferably 50 to 99% by mass, more preferably 50 to 80% by mass, and 60 to 70% by mass.

By setting the proportion of the structural unit (d) in the water-soluble copolymer in the above range, an oil-in-water emulsion composition having a further reduced sticky feeling can be provided.

In the present invention, the mass ratio of the structural unit (c) and the structural unit (d) constituting the water-soluble copolymer is preferably 10:90 to 50:50, more preferably 20:80 to 50:50, and still more preferably 30:70 to 40: 60.

The molar ratio of the structural unit (c) to the structural unit (d) constituting the water-soluble copolymer is preferably 15:85 to 62:38, more preferably 29:71 to 62:38, and still more preferably 41:59 to 52: 48.

When the mass ratio and the molar ratio of the structural unit (c) to the structural unit (d) in the water-soluble copolymer are in the above ranges, a water-soluble copolymer having excellent emulsifying power suitable for forming an oil-in-water type emulsion composition can be obtained.

In the present invention, the average molecular weight of the water-soluble copolymer is preferably 20000 to 110000, more preferably 20000 to 80000, more preferably 30000 to 80000, more preferably 40000 to 70000, even more preferably 50000 to 70000, even more preferably 57000 to 66000.

Here, the average molecular weight means a weight average molecular weight in terms of polystyrene measured by GPC.

<2> emulsion composition

The emulsified composition of the present invention is characterized by being substantially free of an emulsifier other than the above-mentioned water-soluble copolymer.

Here, "substantially not containing an emulsifier other than the above-mentioned water-soluble copolymer" means that the content of the emulsifier other than the above-mentioned water-soluble copolymer is 0.3% by mass or less, preferably 0.1% by mass or less, more preferably 0.01% by mass or less, and further preferably 0.001% by mass or less. Further, it is particularly preferable that the emulsifier other than the above-mentioned water-soluble copolymer is not contained.

The content of the water-soluble copolymer in the emulsion composition is preferably 0.1 to 50% by mass, more preferably 0.5 to 30% by mass.

When the content of the water-soluble copolymer is in the above range, the emulsion stability of the emulsion composition can be further improved.

The content of the aqueous phase and the oil phase in the emulsion composition of the present invention can be appropriately adjusted by changing the ratio of the structural unit (c) and the structural unit (d) in the water-soluble copolymer.

The contents of the oil phase and the water phase in the case of using a water-soluble copolymer containing the structural unit (c) and the structural unit (d) in a ratio suitable for forming the oil-in-water type emulsion composition will be described below.

In the present specification, it is assumed that the water-soluble copolymer of the present invention is not contained in the oil phase and the oil phase components and the aqueous phase components.

The content of the oil phase component in the emulsion composition of the present invention is preferably 0.01 to 80% by mass, and more preferably 0.1 to 70% by mass.

When the content of the oil phase component is in the above range, the emulsion stability of the emulsion composition can be improved.

The oil phase component is an oil agent and a lipophilic component, and refers to a component contained in the oil phase in the emulsion composition.

In the emulsion composition of the present invention, the mass ratio of the water-soluble copolymer to the oil phase component is preferably 1:100 to 1:0.2, more preferably 1:70 to 1: 0.3.

When the mass ratio of the water-soluble copolymer to the oil phase component is in the above range, the emulsion stability of the emulsion composition can be improved.

In the emulsion composition of the present invention, the mass ratio of the oil phase to the water phase is preferably 0.1:99.9 to 80:20, and more preferably 1:99 to 65: 35.

By setting the mass ratio of the oil phase to the water phase in the above range, a stable oil-in-water type emulsion composition can be formed.

The components contained in the oil phase and the water phase are not particularly limited.

Examples of the oil agent constituting the oil phase include: liquid fat, solid fat, wax, hydrocarbon oil, higher fatty acid, higher alcohol, synthetic ester oil, silicone oil, and the like.

Examples of the liquid fat and oil include: avocado oil, camellia oil, tortoise oil, macadamia nut oil, corn oil, mink oil, olive oil, rapeseed oil, egg yolk oil, sesame oil, nut oil, wheat germ oil, Chinese wampee oil, castor oil, linseed oil, safflower oil, cottonseed oil, perilla oil, meadowfoam seed oil, soybean oil, peanut oil, tea seed oil, torreya seed oil, rice bran oil, china tung oil, japanese tung oil, jojoba oil, germ oil, triglycerin, tricaprylin, glycerol triisopalmitate and the like.

Examples of the solid fat and oil include: cocoa butter, coconut oil, horse fat, hardened coconut oil, palm oil, beef tallow, mutton tallow, hardened beef tallow, palm kernel oil, lard, beef bone fat, medlar kernel oil, hardened oil, beef foot fat, medlar, hardened castor oil and the like.

Examples of the waxes include: beeswax, candelilla wax, cotton wax, carnauba wax, bayberry wax, insect wax, spermaceti wax, montan wax, rice bran wax, lanolin, kapok wax, lanolin acetate, liquid lanolin, sugarcane wax, lanolin fatty acid isopropyl, hexyl laurate, reduced lanolin, jojoba wax, hard lanolin, shellac wax, POE lanolin alcohol ether, POE lanolin alcohol acetate, POE cholesterol ether, lanolin fatty acid polyethylene glycol, POE hydrogenated lanolin alcohol ether, and the like.

Examples of the hydrocarbon oil include: flowing paraffin, ceresin, pristane, paraffin, ceresin, squalene, vaseline, microcrystalline wax, etc.

Examples of the higher fatty acid include: lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, 12-hydroxystearic acid, undecylenic acid, valeric acid, and the like.

Examples of the higher alcohol include: cetyl alcohol, stearyl alcohol, behenyl alcohol, stearyl alcohol, myristyl alcohol, cetostearyl alcohol, and the like.

Examples of synthetic ester oils include: isopropyl myristate, cetyl octanoate, octyldodecyl myristate, isopropyl palmitate, butyl stearate, hexyl laurate, myristyl myristate, decyl oleate, hexyldecyl dimethyloctanoate, cetyl lactate, myristyl lactate, lanolin acetate, isocetyl stearate, isocetyl isostearate, sucrose stearate, sucrose oleate, cholesterol 12-hydroxystearate, ethylene glycol di-2-ethylhexanoate, dipentaerythritol fatty acid esters, N-alkylethyleneglycol monoisostearate, neopentyl glycol didecanoate, diisostearyl malate, di-2-heptylundecyl glyceride, trimethylolpropane tri-2-ethylhexanoate, trimethylolpropane triisostearate, amyl tetra-2-ethylhexanoate erythritol ester, glyceryl tri-2-ethylhexanoate, trimethylolpropane triisostearate, cetyl 2-ethylhexanoate, 2-ethylhexyl palmitate, glyceryl trimyristate, glyceryl tri-2-heptylundecanoate, methyl ricinoleate, oil oleate, cetostearyl alcohol, glyceryl acetate, 2-heptyldodecyl palmitate, cetyl palmitate, diisobutyl adipate, 2-octyldodecyl N-lauroyl-L-glutamate, di-2-heptylundecyl adipate, ethyl laurate, di-2-ethylhexyl sebacate, 2-hexyldecyl myristate, 2-hexyldecyl palmitate, 2-hexyldecyl adipate, diisopropyl sebacate, 2-ethylhexyl succinate, 2-ethylhexyl sebacate, glyceryl palmitostearate, glyceryl trimyristate, glyceryl palmitostearate, ethyl acetate, butyl acetate, amyl acetate, triethyl citrate, and the like.

Examples of the silicone oil include: chain polysiloxanes such as dimethylpolysiloxane, methylphenylpolysiloxane, and methylhydrogenpolysiloxane, and cyclic polysiloxanes such as decamethylpolysiloxane, dodecamethylpolysiloxane, and tetramethyltetrahydropolysiloxane.

One or more kinds of oil agents may be used.

Examples of the additive components include humectants such as polyethylene glycol, glycerin, 1, 3-butylene glycol, erythritol, sorbitol, xylitol, maltitol, lower alcohols such as ethanol, antioxidants such as benzoic acid, salicylic acid, alkyl p-hydroxybenzoate, hexachlorophene, p-aminobenzoic acid (hereinafter abbreviated as "PABA"), PABA monoglyceride, N-dipropoxypPABA ethyl ester, N-diethoxypPABA ethyl ester, N-dimethyl PABA methyl ester, N-dimethyl PABA ethyl ester, N-dimethyl PABA butyl ester, N-dimethyl PABA 2-ethylhexylketone, and anthranilic acid-based ultraviolet absorbers such as isopropyl cinnamate, 2-trimethoxy phenyl benzoate, 2-methoxy benzophenone, 2-trimethoxy phenyl cinnamate, 2-methoxy phenyl cinnamate, 2-ethyl benzophenone (such as salicylic acid, 2-methoxy phenyl cinnamate, 2-methoxy phenyl benzoate, 3-isopropyl cinnamate, 2-methoxy phenyl cinnamate, 2-isopropyl cinnamate, 2-methoxy phenyl benzoate, 2-isopropyl cinnamate, 2-benzoyl benzoate, 2-methoxy phenyl cinnamate, 2-isopropyl cinnamate, 2-methoxy phenyl benzoate, 2-isopropyl cinnamate, 2-isopropyl cinnamate, 2-isopropyl cinnamate, 2-5-2-isopropyl cinnamate, 2-isopropyl-2-isopropyl-2-isopropyl-2-isopropyl-2-isopropyl-5-isopropyl-benzoyl-isopropyl-benzoyl-2-benzoyl-2-benzoyl-2-isopropyl-2-benzoyl-isopropyl-benzoyl-4-2-benzoyl-isopropyl-benzoyl-2-benzoyl-2-benzoyl-2-4-benzoyl-2-benzoyl-2-benzoyl-isopropyl-benzoyl-4-benzoyl.

The emulsified composition of the present invention can be produced by separately preparing the water phase component and the oil phase component comprising the above-mentioned water-soluble copolymer, and stirring and mixing them in a conventional manner.

The emulsion composition of the present invention is low in irritation and low in viscosity, and therefore is preferably used as a cosmetic such as an emulsion, a cream, a cosmetic liquid, a sunscreen cream, and a liquid foundation, an external preparation for skin, a quasi-drug, a pharmaceutical, and the like.

<3> emulsifier

The invention also relates to an emulsifier consisting of the water-soluble copolymer. The above-mentioned items described with respect to the water-soluble copolymer and the emulsifying composition can be applied to the emulsifier of the present invention.

<4> method for producing emulsion composition

The present invention also relates to a method for producing an emulsified composition using the above-mentioned emulsifier of the present invention. The process of the present invention is characterized in that an emulsifier other than the emulsifier of the present invention is not used. The above-mentioned items described with respect to the water-soluble copolymer and the emulsion composition can be applied to the production method of the present invention.

The skin cleansing milk of the present invention for solving the third and fourth problems is characterized by containing a water-soluble copolymer having a structural unit (e) derived from a hydrophobic monomer and a structural unit (f) derived from a hydrophilic monomer. Hereinafter, the water-soluble copolymer, which is a copolymer of a hydrophobic monomer, a hydrophilic monomer, and a copolymer thereof, will be described in the item <1 >.

<1> Water-soluble copolymer

[ 1] hydrophobic monomer

In the present invention, a water-soluble copolymer containing, as an essential structural unit, one or two or more structural units derived from the hydrophobic monomer represented by the above general formula (1), (7) or (8) (hereinafter, may be simply referred to as "structural unit (7)") is used.

(1-1) hydrophobic monomer represented by the general formula (7)

Examples of the branched hydrocarbon group having 13 to 30 carbon atoms and not having a ring structure represented by R15 include: 1-methyldodecyl, 11-methyldodecyl, 3-ethylundecyl, 3-ethyl-4, 5, 6-trimethyloctyl, 1-methyltridecyl, 1-hexynyl, 2-butyldecyl, 2-hexynyl, 4-ethyl-1-isooctyl, 1-methylpentadecyl, 2-hexylundecyl group, 2-octylundecyl group, 2-hexyldodecyl group, 16-methylpentadecyl group, 9-methylpentadecyl group, 7-methyl-2- (3-methylhexyl) decyl group, 3,7,11, 15-tetramethylhexadecyl group, 2-octyldodecyl group, 2-decyltetradecyl group, 2-dodecylhexadecyl group and the like.

Examples of the hydrocarbon group of 6 to 12 carbon atoms having 2 or more branches and not containing a ring structure represented by R15 include: 2, 2-dimethylbutyl, 2, 3-dimethylbutyl, 3-dimethylbutyl, 1,2, 2-trimethylpropyl, 1-dimethylpentaynyl, 1-isopropylbutyl, 1-isopropyl-2-methylpropyl, 1-diethylpropyl, 1-ethyl-1-isopropylpropyl, 2-ethyl-4-methylpentyl, 1-propyl-2, 2-dimethylpropyl, 1, 2-trimethylpentyl, 1-isopropyl-3-methylbutyl, 1, 2-dimethyl-1-ethylbutyl, 1, 3-dimethyl-1-ethylbutyl, 1-ethyl-1-isopropyl-propyl, 1, 1-dimethylhexyl, 1-methyl-1-ethylpentyl, 1-methyl-1-propylbutyl, 1, 4-dimethylhexyl, 1-ethyl-3-methylpentyl, 1, 5-dimethylhexyl, 1-ethyl-6-methylheptyl, 1,3, 3-tetramethylbutyl, 1, 2-dimethyl-1-isopropylpropyl, 3-methyl-1- (2, 2-dimethylethyl) butyl, 1-isopropylhexyl, 3, 5-trimethylhexyl, 2-isopropyl-5-methylhexyl, 1, 5-dimethyl-1-ethylhexyl, 3, 7-dimethyloctyl, 2,4, 5-trimethylheptyl, 2,4, 5-trimethylhexyl, 1, 4-dimethylheptyl, 1, 4-dimethylhexyl, 3, 2-dimethylhexyl, 1, 2-ethylhexyl, 3-dimethylhexyl, 2-ethyl, 2,4, 6-trimethylheptyl, 3, 5-dimethyl-1- (2, 2-dimethylethyl) hexyl and the like.

(1-2) hydrophobic monomer represented by the general formula (1) or (8)

Examples of the alkyl group represented by R1 and R16 include a methyl group, an ethyl group, a propyl group, an isopropyl group, and a cyclopropyl group. In the present invention, R1 is preferably a hydrogen atom or a methyl group.

Examples of the acyl group having 6 to 22 carbon atoms, which is branched and does not have a ring structure, represented by R2, R3, R17, R18 and R19 include: 2-methylpentanoyl, 3-methylpentanoyl, 4-methylpentanoyl, 2-ethylbutanoyl, 2-dimethylbutanoyl, 3-dimethylbutanoyl, 2-methylhexanoyl, 4-methylhexanoyl, 5-methylhexanoyl, 2-dimethylpentanoyl, 4-dimethylpentanoyl, 2-methylheptanoyl, 2-ethylhexyl, 2-propylpentanoyl, 2-dimethylhexanoyl, 2, 3-trimethylpentanoyl, 2-methyloctanoyl, 3, 5-trimethylhexanoyl, 2-methylnonanoyl, 4-methylnonanoyl, 8-methylnonanoyl, 4-ethyloctanoyl, 2-ethyloctanoyl, 2-butylhexanoyl, 2-tert-butylhexanoyl, 2-diethylhexanoyl, 2-dimethyloctanoyl, 3, 7-dimethyloctanoyl, neodecanoyl, 7-methyldecanoyl, 2-methyl-2-ethyloctanoyl, 2-methylundecanoyl, 10-methylundecanoyl, 2-dimethyldecanoyl, 2-ethyldecanoyl, 2-butyloctanoyl, diethyloctanoyl, 2-tert-butyl-2, 2, 4-trimethylpentanoyl, 10-methyldodecanoyl, 3-methyldodecanoyl, 4-methyldodecanoyl, 11-methyldodecanoyl, 10-ethylundecanoyl, 12-methyltridecanoyl, 2-butyldecanoyl, 2-hexyloctanoyl group, 2-butyl-2-ethyloctanoyl group, 12-methyltetradecanoyl group, 14-methylpentadecanoyl group, 2-butyldodecanoyl group, 2-hexyldecanoyl group, 16-methylpentadecanoyl group, 2, 2-dimethylhexanoyl group, 2-butylhexadecanoyl group, 2-hexyldodecanoyl group, 2,4,10, 14-tetramethylpentanoyl group, 18-methylnonadecanoyl group, 3,7,11, 15-tetramethylhexadecanoyl group, 19-methyleicosanoyl group and the like.

Examples of the acyl group having 10 to 22 carbon atoms and a branched chain, which is not a ring structure, represented by R2, R3, R17, R18 and R19 in the preferred embodiment include: 2-methylnonanoyl, 4-methylnonanoyl, 8-methylnonanoyl, 4-ethyloctanoyl, 2-butylhexanoyl, 2-tert-butylhexanoyl, 2-diethylhexanoyl, 2-dimethyloctanoyl, 3, 7-dimethyloctanoyl, neodecanoyl, 7-methyldecanoyl, 2-methyl-2-ethyloctanoyl, 2-methylundecanoyl, 10-methylundecanoyl, 2-dimethyldecanoyl, 2-ethyldecanoyl, 2-butyloctanoyl, diethyloctanoyl, 2-tert-butyl-2, 2, 4-trimethylpentanoyl, 10-methyldodecanoyl, 3-methyldodecanoyl, 4-methyldodecanoyl, 11-methyldodecanoyl, 10-ethylundecanoyl, 12-methylundecanoyl, 2-butyldecanoyl, 2-hexyloctanoyl, 2-butyl-2-ethyloctanoyl, 12-methyltetradecanoyl, 14-methylpentadecanoyl, 2-butyldodecanoyl, 2-hexyldecanoyl, 16-methylpentadecanoyl, 2-dimethylhexanoyl, 2-butylhexadecanoyl, 2-hexyldodecanoyl, 2,4,10, 14-tetramethylpentanoyl, 18-methylnonadecanoyl, 3,7,11, 15-tetramethylhexadecanoyl, 19-methyldicosanoyl and the like.

The group derived from a triol represented by X in the general formula (1) is not particularly limited as long as it is a group in which an OH group is removed from a triol, and preferable examples thereof include a group in which an OH group is removed from a triol selected from the group consisting of glycerin, trimethylolpropane and trimethylolethane.

The group derived from a tetrahydric alcohol represented by Y in the general formula (8) is not particularly limited as long as it is a group in which an OH group is removed from a tetrahydric alcohol, and preferable examples thereof include a group in which an OH group is removed from a tetrahydric alcohol selected from the group consisting of diglycerin, pentaerythritol, erythritol, D-threitol, and L-threitol.

[ 2] hydrophilic monomer

As the hydrophilic monomer in the present invention, a polymerizable carboxylic acid and compounds represented by the above general formulae (2), (9), (10) and (11) can be used.

(2-1) polymerizable carboxylic acid

In the present invention, as the polymerizable carboxylic acid or a salt thereof, specifically, there can be exemplified: acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, and sodium, potassium, ammonium, amine salts thereof, and the like. Among them, acrylic acid, methacrylic acid and salts thereof are particularly preferable because of their high polymerizability. When a structural unit derived from a salt of a polymerizable carboxylic acid is introduced into the water-soluble copolymer of the present invention, the polymerizable carboxylic acid may be previously formed into a salt and subjected to a polymerization reaction, or a structural unit derived from a polymerizable carboxylic acid may be introduced into the water-soluble copolymer by a polymerization reaction and then neutralized with an alkali to form a salt.

(2-2) hydrophilic monomer represented by the general formula (2)

In the general formula (2), n is in a numerical range of 6 to 40.

Among the monomers represented by the above general formula (2), the monomer wherein R5 is an acryl group includes, specifically: polypropylene glycol (9) monoacrylate, polypropylene glycol (13) monoacrylate, polypropylene glycol (9) monomethacrylate, polypropylene glycol (13) monomethacrylate, and the like. In addition, the number in parentheses represents N. Many of these polymers are available as commercial products. Specific examples of such commercially available products include those sold under the trade names "BLEMMER" AP-400, AP-550, AP-800, PP-500 and PP-800 (all manufactured by Nippon fat and oil Co., Ltd.).

Among the monomers represented by the general formula (2), the monomers wherein R5 is a vinyl group include, specifically: polyethylene glycol (10) monoacrylate, polyethylene glycol (8) monomethacrylate, polyethylene glycol (23) monoacrylate, polyethylene glycol (23) monomethacrylate, methoxypolyethylene glycol (9) acrylate, methoxypolyethylene glycol (9) methacrylate, methoxypolyethylene glycol (23) methacrylate, vinyl polyethylene glycol (オレイロキシポリエチレングリコール) (18) methacrylate, lauroyl polyethylene glycol (18) acrylate, lauroyloxy polyethylene glycol (10) methacrylate, stearoxy polyethylene glycol (30) monomethacrylate, and the like.

(2-3) hydrophilic monomer represented by the general formula (9)

Specific examples of the hydrophilic monomer represented by the general formula (9) include: 2-Acryloyloxyethylphosphorylcholine (APC), 2-Methacryloyloxyethylphosphorylcholine (MPC). These monomers can be synthesized by the following methods, for example, as described in Polymer Journal, Vol.22, No. 5.

< Synthesis method >

(2-4) hydrophilic monomer represented by the general formula (10)

Among the hydrophilic monomers represented by the general formula (10), the reducing sugar having a group whose hydrogen has been removed from the hydroxyl group at the 1-position of the reducing sugar represented by G — O "may be specifically exemplified by one or more selected from the group consisting of monosaccharides such as glucose, mannose, galactose, arabinose, xylose, and ribose, maltose, lactose, disaccharides such as cellobiose, trisaccharides such as maltotriose, and oligosaccharides such as maltooligosaccharides, among which one or more selected from the group consisting of glucose, galactose, arabinose, xylose, ribose, maltose, lactose, and cellobiose is preferable, and glucose is particularly preferable. Also, as the monomer represented by the general formula (10), glycosyloxyethyl methacrylate (hereinafter, abbreviated as GEMA) or glycosyloxyethyl acrylate (hereinafter, abbreviated as GEA) is preferable.

In the monomer of the general formula (11), the amino acid as the amino acid residue represented by R23 is not particularly limited as long as it is a known amino acid, and specifically, it may be exemplified by: glycine, alanine, glutamine, lysine, arginine, and the like. Among them, lysine residue is particularly preferable because the resulting water-soluble copolymer is excellent in the skin barrier recovery effect.

The polyamine in the polyamine residue represented by R23 is an amine having two or more amino groups that may be substituted with an alkyl group in the same molecule, and specifically, it can be exemplified by: diamines, triamines, tetramines or amines in which the hydrogen atoms of the amino groups have been replaced by alkyl groups. Among them, diamines are preferable because the skin external preparation containing the obtained water-soluble copolymer is particularly excellent in feeling of use, and specific examples thereof are particularly preferable because raw materials are easily available at the time of synthesis, and thus, there are listed: ethylenediamine, 1, 4-diamino-n-butane, 1, 6-diamino-n-hexane, and the like.

As specific examples of the monomer represented by the general formula (11) and salts thereof, the above-mentioned compounds 1 to 11 and salts thereof are preferably exemplified.

As described above, in the present invention, as the hydrophilic polymer, the general formula (2), the general formula (9), the general formula (10), and the general formula (11) can be used.

[ 3] Water-soluble copolymer

Among such water-soluble copolymers, the (PEG-23 methoxy methacrylate/glyceryl diisostearate methacrylate) copolymer is particularly preferably used.

By containing such a water-soluble copolymer, a skin cleansing cream with less tension after use can be obtained.

The (PEG-23 methoxymethacrylate/diisostearic acid glyceryl methacrylate) copolymer mainly contains, as the structural unit (e), a structural unit (e) derived from a hydrophobic monomer in which R24 and R25 are 16-methylpentadecanoyl groups among the hydrophobic monomers represented by the general formula (15).

And a structural unit (f) derived from a hydrophilic monomer represented by the general formula (2) wherein R4 is a methyl group, R5 is a vinyl group, R6 is a methyl group, and n is 23.

In the present invention, the proportion of the structural unit (e) in the water-soluble copolymer to the total structural units is preferably 1 to 60% by mass, more preferably 10 to 50% by mass, and still more preferably 20 to 40% by mass.

By setting the proportion of the structural unit (e) in the water-soluble copolymer to the above range, a skin cleansing cream with a further reduced feeling of tightness after use can be provided.

In the present invention, the proportion of the structural unit (f) in the water-soluble copolymer to the total structural units is preferably 40 to 99% by mass, more preferably 50 to 90% by mass or 60 to 80% by mass.

By setting the proportion of the structural unit (f) in the water-soluble copolymer to the above range, a skin cleansing cream with a further reduced feeling of tightness after use can be provided.

In the present invention, the mass ratio of the structural unit (e) and the structural unit (f) constituting the water-soluble copolymer is preferably 1:99 to 60:40, more preferably 10:90 to 50:50, and still more preferably 20:80 to 40: 60.

The molar ratio of the structural unit (e) to the structural unit (f) constituting the water-soluble copolymer is preferably 1:99 to 71:29, more preferably 15:85 to 62:38, still more preferably 29:71 to 52:48, and still more preferably 35:65 to 45: 55.

When the mass ratio and the molar ratio of the structural unit (e) to the structural unit (f) in the water-soluble copolymer are in the above ranges, a water-soluble copolymer having a more excellent effect of reducing a tight feeling can be obtained.

In the present invention, the average molecular weight of the water-soluble copolymer is preferably 20000 to 110000, more preferably 20000 to 80000, more preferably 30000 to 80000, more preferably 40000 to 70000, even more preferably 50000 to 70000, and even more preferably 57000 to 66000.

<2> skin cleansing milk

[ 1] dosage forms

Skin cleansing milk refers to a composition containing a cleansing ingredient, which is used for the purpose of removing skin dirt such as sebum. As described above, the skin cleansing cream has a problem that it causes a tight feeling to the skin after use because it has an effect of removing sebum existing on the skin.

The skin cleansing milk of the present invention is characterized by containing the above-mentioned water-soluble copolymer. According to the invention, the original clean force of the skin cleaning cream is not hindered or improved, and the skin tightness after use is reduced.

The formulation of the skin cleansing milk of the present invention is not particularly limited as long as it is a formulation generally used for skin cleansing milk. Typical skin cleansing milks include solid, powdery, cream, liquid, and gel-like skin cleansing milks, but the present invention can be applied to any formulation.

The content of the water-soluble copolymer in the skin cleansing milk in the form of a liquid such as a cream, liquid, or gel is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass, and still more preferably 1 to 3% by mass.

By setting the content of the water-soluble copolymer in the above range, the original cleansing power of the skin cleansing cream is not hindered, and the skin tightness after use can be further reduced.

Skin cleansing milk can be classified into a type for foaming use and a type for non-foaming use. No matter which type of skin cleansing milk the invention is applied to, the original clean force of the skin cleansing milk can not be hindered, and the skin tightness after use can be reduced.

In the skin cleansing milk of the type to be used in foaming, the content of the water-soluble copolymer is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, further preferably 0.8% by mass or more, and further preferably 1% by mass or more, from the viewpoint of improving the foaming property.

The content of the water-soluble copolymer is preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 3% by mass or less, and even more preferably 1% by mass or less, from the viewpoint of reducing the sticky feeling of the skin after use.

As the skin cleansing milk of the type used by foaming, a cream-like skin cleansing milk is preferably cited.

In the skin cleansing milk of the type used without foaming, the content of the water-soluble copolymer is preferably 0.1 to 10% by mass, more preferably 0.5 to 5% by mass, even more preferably 0.6 to 3% by mass, and even more preferably 0.7 to 2% by mass, from the viewpoint of improving the spreadability on the skin.

As a type of skin cleansing milk used without foaming, gel-like skin cleansing milk is preferably cited.

(2) Skin cleansing milk containing surfactant

Skin cleansing milk containing a surfactant as a cleansing ingredient has a strong cleansing power, but has a problem of strong skin tightness after use. Therefore, the present invention is preferably applied to a skin cleansing milk containing a surfactant.

The surfactant that can be contained in the skin cleansing milk of the present invention is not particularly limited as long as it is a surfactant that is generally used in skin cleansing milk, and any of ionic surfactants and nonionic surfactants can be used.

The ionic surfactant may be any of anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants.

Examples of the anionic surfactant include fatty acid soaps such as sodium fatty acid, potassium fatty acid, and triethanolamine fatty acid, polyoxyethylene groups such as sodium lauryl sulfate, potassium lauryl sulfate, and triethanolamine lauryl sulfate, alkyl sulfate ester salts, polyoxyethylene groups such as sodium lauryl phosphate, potassium lauryl phosphate, and triethanolamine lauryl phosphate, and alkyl phosphate ester salts, sulfosuccinate alkyl ester salts, and the like.

Examples of the anionic surfactant include: alkyltrimethylammonium salts, alkylpyridinium salts, distearyldimethylammonium chloride, poly (N, N' -dimethyl-3, 5-methylenepiperidinium) chloride, alkyl quaternary ammonium salts, alkyl dimethylbenzylammonium salts, alkyl isoquinolinium salts, dialkyl morpholine salts, POE-alkylamine, alkylamine salts, polyamine fatty acid derivatives, pentanol fatty acid derivatives, benzalkonium chloride, benzethonium chloride, and the like.

Examples of the amphoteric surfactant include: imidazoline-based amphoteric surfactants, betaine-based surfactants, and the like.

As the nonionic surfactant, there can be preferably exemplified: glycerin fatty acid ester, polyglycerin fatty acid ester, polyoxyethylene glycerin fatty acid ester, sorbitol fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, polyoxyethylene alkylphenyl ether, polyoxyethylene lanolin-lanolin alcohol-beeswax derivative, polyoxyethylene castor oil-hardened castor oil, polyoxyethylene sterol-hydrogenated sterol, polyoxyethylene alkyl ether, polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene fatty acid ester, polyoxyethylene alkyl ether fatty acid ester, polyoxyethylene hardened castor oil fatty acid ester, polyoxyethylene trimethylolpropane fatty acid ester, polyethylene glycol fatty acid ester, sucrose fatty acid ester, polyoxyethylene polyoxypropylene block copolymer, organically modified silicone, and the like.

The content of these surfactants is not particularly limited and may be appropriately set according to the kind of the surfactant.

Hereinafter, skin cleansing milk of a mode of containing a fatty acid soap, a mode of containing a nonionic surfactant, and a gel-like mode will be described more specifically.

(2-1) skin cleansing milk containing fatty acid soap

By applying the present invention to a skin cleansing milk containing a fatty acid soap, the skin tightness after use can be reduced without impairing the good foaming and cream-like foam quality of the skin cleansing milk.

The form of the skin cleansing milk containing the fatty acid soap may be any of solid, liquid, and cream, but it is preferable to use a liquid or cream. In particular, a foaming manner of cream-like skin cleansing milk is preferably employed.

The fatty acid constituting the fatty acid soap is not particularly limited as long as it is a fatty acid applicable to a skin cleansing cream, and may be saturated or unsaturated, and is preferably a fatty acid having 8 to 24 carbon atoms, and more preferably 10 to 22 carbon atoms. Specific examples of preferred fatty acids include: lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, oleic acid, hydroxystearic acid, hydroxydecanoic acid, coconut oil fatty acid, reduced coconut oil fatty acid, tallow fatty acid, reduced tallow fatty acid, palm kernel fatty acid, and the like. Among these fatty acids, one or more selected from myristic acid, palmitic acid, and stearic acid is preferably contained from the viewpoint of foaming, safety, and stability, and three of myristic acid, palmitic acid, and stearic acid are particularly preferably used. Examples of the alkaline agent which forms a salt with these higher fatty acids include: alkali metal salts such as sodium and potassium, ammonium salts, monoethanolamine salts, diethanolamine salts, triethanolamine salts, alkanolamine salts such as 2-amino-2-methylpropanol and 2-amino-2-methylpropanol, and basic amino acid salts such as lysine and arginine.

The content of the fatty acid contained in the skin cleansing milk is not particularly limited. In the case of using a cream-like skin cleansing milk, the fatty acid content is preferably 10 to 70% by mass, more preferably 20 to 60% by mass, and still more preferably 30 to 50% by mass.

The water-soluble copolymer and the fatty acid are contained in a mass ratio of preferably 1:500 to 1:2, more preferably 1:200 to 1:3, and even more preferably 1:100 to 1:5, from the viewpoint of reducing the feeling of tightness after use of the skin cleansing milk.

From the viewpoint of improving the foaming property, the content mass ratio of the water-soluble copolymer to the fatty acid is preferably 1:200 to 1:2, more preferably 1:100 to 1:5, and still more preferably 1:50 to 1: 10.

The content mass ratio of the water-soluble copolymer to the fatty acid is preferably 1:500 to 1:10, more preferably 1:200 to 1:20, and even more preferably 1:100 to 1:50, from the viewpoint of reducing the sticky feeling of the skin after use.

(2-2) skin cleansing milk containing nonionic surfactant

The present invention can effectively reduce the skin tightness after use even when applied to a skin cleansing milk containing a nonionic surfactant. As the nonionic surfactant, the nonionic surfactants described above can be used without limitation.

In the embodiment including the nonionic surfactant, the content of the water-soluble copolymer is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and further preferably 1% by mass or more, from the viewpoint of reducing a tight feeling after use.

From the viewpoint of improving the cleanliness, the content of the water-soluble copolymer is preferably 0.5% by mass or more, more preferably 1% by mass or more, further preferably 2% by mass or more, and further preferably 3% by mass or more.

The water-soluble copolymer and the nonionic surfactant are contained in a mass ratio of preferably 1:20 to 1:0.5, more preferably 1:10 to 1:0.7, and even more preferably 1:5 to 1:1, from the viewpoint of reducing the feeling of tightness after use of the skin cleansing milk.

From the viewpoint of improving the cleanliness, the content mass ratio of the water-soluble copolymer to the nonionic surfactant is preferably 1:10 to 1:0.5, more preferably 1:5 to 1:0.5, still more preferably 1:3 to 1:0.6, and still more preferably 1:1.5 to 1: 0.7.

In the case of using a gel-like skin cleansing milk containing a nonionic surfactant, the mass ratio of the water-soluble copolymer to the nonionic surfactant is preferably 1:15 to 1:0.7, more preferably 1:10 to 1:1, and even more preferably 1:7 to 1:3, from the viewpoint of improving the spreadability on the skin during use.

[ 3] others

The skin cleansing milk of the present invention may contain, in addition to the above-mentioned components, any component usually used in an external skin preparation, examples of such optional components include oils and waxes such as macadamia nut oil, avocado oil, corn oil, olive oil, rapeseed oil, sesame oil, castor oil, safflower oil, cottonseed oil, jojoba oil, coconut oil, palm oil, liquid lanolin, hardened coconut oil, hardened oil, cut wax, hardened castor oil, beeswax, candelilla wax, carnauba wax, rock field wax, lanolin, reduced lanolin, hard lanolin, jojoba wax, hydrocarbon waxes such as fluid paraffin, squalane, celadone, ceresin, higher fatty acids such as oleic acid, isostearic acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, undecylenic acid, higher fatty acids such as cetyl alcohol, stearyl alcohol, behenyl alcohol, myristyl alcohol, cetearyl alcohol, stearic acid, isopropyl alcohol, isopropyl myristate, myristyl alcohol, caprylic acid, capryl alcohol, capryl glycol, caprylic alcohol, caprylic acid, vitamin B, caprylic acid, vitamin B, caprylic acid, vitamin B, caprylic acid, vitamin B.

The skin cleansing milk of the present invention can be produced by treating the above-mentioned respective ingredients according to a conventional method.

The invention is preferably applied to a facial cleanser. According to the present invention, a facial cleanser that is less likely to feel skin tightness after cleansing can be provided.

The sunscreen cosmetic composition of the present invention for solving the fifth problem is characterized by containing the four components [ 1] to [ 4] as essential components. The components [ 1] to [ 4] are described in detail below.

<1> component (A) … Water-soluble copolymer

[ 1] hydrophobic monomer

The component (a) is a water-soluble copolymer containing, as an essential structural unit, one or two or more structural units derived from the hydrophobic monomer represented by the above general formula (1), (7) or (8) (hereinafter, may be simply referred to as "structural unit (7) or the like").

(1-1) hydrophobic monomer represented by the general formula (7)

Examples of the branched hydrocarbon group having 13 to 30 carbon atoms and not having a ring structure represented by R15 include: 1-methyldodecyl, 11-methyldodecyl, 3-ethylundecyl, 3-ethyl-4, 5, 6-trimethyloctyl, 1-methyltridecyl, 1-hexynyl, 2-butyldecyl, 2-hexynyl, 4-ethyl-1-isooctyl, 1-methylpentadecyl, 2-hexyldecyl, 2-octyldecyl, 2-hexyldodecyl, 16-methylpentadecyl, 9-methylpentadecyl, 7-methyl-2- (3-methylhexyl) decyl, 3,7,11, 15-tetramethylhexadecyl, 2-octyldodecyl, 2-decyltetradecyl, 2-dodecylhexadecyl and the like.

Examples of the hydrocarbon group having 6 to 12 carbon atoms, which is represented by R15 and has 2 or more branches without a ring structure, include: 2, 2-dimethylbutyl, 2, 3-dimethylbutyl, 3-dimethylbutyl, 1,2, 2-trimethylpropyl, 1-dimethylpentyl, 1-isopropylbutyl, 1-isopropyl-2-methylpropyl, 1-diethylpropyl, 1-ethyl-1-isopropylpropyl, 2-ethyl-4-methylpentyl, 1-propyl-2, 2-dimethylpropyl, 1, 2-trimethylpentyl, 1-isopropyl-3-methylbutyl, 1, 2-dimethyl-1-ethylbutyl, 1, 3-dimethyl-1-ethylbutyl, 1-ethyl-1-isopropyl-propyl, 1, 3-dimethylbutyl, 1, 3-isopropylbutyl, 1, 3-dimethylbutyl, 1-isopropylbutyl, 1, 2-isopropylbutyl, 1, 1-dimethylhexyl, 1-methyl-1-ethylpentyl, 1-methyl-1-propylbutyl, 1, 4-dimethylhexyl, 1-ethyl-3-methylpentyl, 1, 5-dimethylhexyl, 1-ethyl-6-methylheptyl, 1,3, 3-tetramethylbutyl, 1, 2-dimethyl-1-isopropylpropyl, 3-methyl-1- (2, 2-dimethylethyl) butyl, 1-isopropylhexyl, 3,5, 5-trimethylhexyl, 2-isopropyl-5-methylhexyl, 1, 5-dimethyl-1-ethylhexyl, 3, 7-dimethyloctyl, 2,4, 5-trimethylheptyl, 2,4, 5-trimethylhexyl, 1, 4-dimethylheptyl, 1, 4-dimethylhexyl, 3, 2-dimethylhexyl, 1, 2-ethylhexyl, 3-dimethylhexyl, 2-ethyl, 2,4, 6-trimethylheptyl, 3, 5-dimethyl-1- (2, 2-dimethylethyl) hexyl and the like.

(1-2) hydrophobic monomer represented by the general formula (1) or (8)

Examples of the acyl group having 6 to 22 carbon atoms, which is not a ring structure, and which is branched and is represented by R2, R3, R17, R18, and R19, include: 2-methylpentanoyl, 3-methylpentanoyl, 4-methylpentanoyl, 2-ethylbutanoyl, 2-dimethylbutanoyl, 3-dimethylbutanoyl, 2-methylhexanoyl, 4-methylhexanoyl, 5-methylhexanoyl, 2-dimethylpentanoyl, 4-dimethylpentanoyl, 2-methylheptanoyl, 2-ethylhexyl, 2-propylpentanoyl, 2-dimethylhexanoyl, 2, 3-trimethylpentanoyl, 2-methyloctanoyl, 3, 5-trimethylhexanoyl, 2-methylnonanoyl, 4-methylnonanoyl, 8-methylnonanoyl, 4-ethyloctanoyl, 2-ethyloctanoyl, 2-butylhexanoyl, 2-tert-butylhexanoyl, 2-diethylhexanoyl, 2-dimethyloctanoyl, 3, 7-dimethyloctanoyl, neodecanoyl, 7-methyldecanoyl, 2-methyl-2-ethyloctanoyl, 2-methylundecanoyl, 10-methylundecanoyl, 2-dimethyldecanoyl, 2-ethyldecanoyl, 2-butyloctanoyl, diethyloctanoyl, 2-tert-butyl-2, 2, 4-trimethylpentanoyl, 10-methyldodecanoyl, 3-methyldodecanoyl, 4-methyldodecanoyl, 11-methyldodecanoyl, 10-ethylundecanoyl, 12-methyltridecanoyl, 2-butyldecanoyl, 2-hexyloctanoyl group, 2-butyl-2-ethyloctanoyl group, 12-methyltetradecanoyl group, 14-methylpentadecanoyl group, 2-butyldodecanoyl group, 2-hexyldecanoyl group, 16-methylpentadecanoyl group, 2, 2-dimethylhexanoyl group, 2-butylhexadecanoyl group, 2-hexyldodecanoyl group, 2,4,10, 14-tetramethylpentanoyl group, 18-methylnonadecanoyl group, 3,7,11, 15-tetramethylhexadecanoyl group, 19-methyleicosanoyl group and the like.

In a preferred embodiment of the present invention, in the general formulae (1) and (8), R2, R3, R17, R18 and R19 may be the same or different and are each an acyl group having 10 to 22 carbon atoms and having a branch chain and not having a ring structure, or an acyl group having 6 to 9 carbon atoms and having 2 or more branches and not having a ring structure.

Examples of the acyl group having 10 to 22 carbon atoms and a branched chain, which is not a ring structure and is represented by R2, R3, R17, R18 and R19 in the preferred embodiment include: 2-methylnonanoyl, 4-methylnonanoyl, 8-methylnonanoyl, 4-ethyloctanoyl, 2-butylhexanoyl, 2-tert-butylhexanoyl, 2-diethylhexanoyl, 2-dimethyloctanoyl, 3, 7-dimethyloctanoyl, neodecanoyl, 7-methyldecanoyl, 2-methyl-2-ethyloctanoyl, 2-methylundecanoyl, 10-methylundecanoyl, 2-dimethyldecanoyl, 2-ethyldecanoyl, 2-butyloctanoyl, diethyloctanoyl, 2-tert-butyl-2, 2, 4-trimethylpentanoyl, 10-methyldodecanoyl, 3-methyldodecanoyl, 4-methyldodecanoyl, 11-methyldodecanoyl, 10-ethylundecanoyl, 12-methyltridecanoyl, 2-butyldecanoyl, 2-hexyloctanoyl, 2-butyl-2-ethyloctanoyl, 12-methyltetradecanoyl, 14-methylpentadecanoyl, 2-butyldodecanoyl, 2-hexyldecanoyl, 16-methylpentadecanoyl, 2-dimethylhexanoyl, 2-butylhexadecanoyl, 2-hexyldodecanoyl, 2,4,10, 14-tetramethylpentanoyl, 18-methylnonadecanoyl, 3,7,11, 15-tetramethylhexadecanoyl, 19-methyldicosanoyl and the like.

R24 and R25 in the general formula (15) are preferably acyl groups having 10 to 22 carbon atoms and containing no cyclic structure and having a branched chain.

The number of carbon atoms in the main chain of the acyl group of R24 and R25 in the general formula (15) is preferably 9 to 21, more preferably 12 to 20, and still more preferably 16 to 18.

As R24 and R25, specifically, preferred examples can be given: 10-methylundecanoyl, 10-methyldodecanoyl, 11-methyldodecanoyl, 10-ethylundecanoyl, 12-methyltridecanoyl, 12-methyltetradecanoyl, 14-methylpentaneoyl, 16-methylpentaneoyl, 2,4,10, 14-tetramethylpentanoyl, 18-methylnonadecanoyl, 3,7,11, 15-tetramethylhexadecanoyl, 19-methyleicosanoyl, etc.

[ 2] hydrophilic monomer

As the hydrophilic monomer constituting the water-soluble copolymer of the component (a), a polymerizable carboxylic acid and compounds represented by the general formula (2), the general formula (9), (10) and (11) can be used.

(2-1) polymerizable carboxylic acid

(2-2) hydrophilic monomer represented by the general formula (2)

In the general formula (2), n is in a numerical range of 6 to 40.

Among the monomers represented by the general formula (2), the monomers wherein R5 is a vinyl group include, specifically: polyethylene glycol (10) monoacrylate, polyethylene glycol (8) monomethacrylate, polyethylene glycol (23) monoacrylate, polyethylene glycol (23) monomethacrylate, methoxypolyethylene glycol (9) acrylate, methoxypolyethylene glycol (9) methacrylate, methoxypolyethylene glycol (23) methacrylate, vinyl polyethylene glycol (18) methacrylate, lauroyl polyethylene glycol (18) acrylate, lauroyloxypolyethylene glycol (10) methacrylate, stearoyloxypolyethylene glycol (30) monomethacrylate, and the like.

(2-3) hydrophilic monomer represented by the general formula (9)

Specific examples of the hydrophilic monomer represented by the general formula (9) include: 2-Acryloyloxyethylphosphorylcholine (APC), 2-Methacryloyloxyethylphosphorylcholine (MPC). These monomers can be synthesized by the following method described in, for example, PolymerJournal, vol.22, No. 5.

< Synthesis method >

2-bromoethylphosphoryl dichloride, 2-hydroxyethyl methacrylate or 2-hydroxyethyl acrylate is reacted to give 2-methacryloyloxyethyl-2 '-bromoethyl phosphate or 2-acryloyloxyethyl-2' -bromoethyl phosphate, after which these compounds are reacted with triethylamine in methanol.

(2-4) hydrophilic monomer represented by the general formula (10)

Among the hydrophilic monomers represented by the general formula (10), reducing sugars as a group from which hydrogen has been removed from the hydroxyl group at the 1-position of the reducing sugar represented by G — O-, specifically one or two or more selected from the following groups may be exemplified: monosaccharides such as glucose, mannose, galactose, arabinose, xylose, ribose, etc.; disaccharides such as maltose, lactose, cellobiose, and the like; trisaccharides such as maltotriose; oligosaccharides such as malto-oligosaccharides, among which one or more selected from the following group are preferable: glucose, galactose, arabinose, xylose, ribose, maltose, lactose, cellobiose, and particularly preferably glucose. Also, as the monomer represented by the general formula (10), glycosyloxyethyl methacrylate (hereinafter, abbreviated as GEMA) or glycosyloxyethyl acrylate (hereinafter, abbreviated as GEA) is preferable.

(2-5) hydrophilic monomer represented by the general formula (11)

In the monomer of the general formula (11), the amino acid as the amino acid residue represented by R23 is not particularly limited as long as it is a known amino acid, and specifically, it may be exemplified by: glycine, alanine, glutamine, lysine, arginine, and the like. Among these, lysine residue is particularly preferable because the obtained water-soluble copolymer is excellent in the effect of recovering the skin barrier.

The polyamine in the polyamine residue represented by R23 means that the amine has two or more amino groups that may be substituted with an alkyl group in the same molecule, and specifically, the following are exemplified: diamines, triamines, tetramines or amines in which the hydrogen atoms of the amino groups are substituted by alkyl groups. Among them, diamines are preferable because the skin external preparation containing the obtained water-soluble copolymer is particularly excellent in feeling of use, and specific examples thereof are particularly preferable because raw materials are easily available at the time of synthesis, and thus, there are listed: ethylenediamine, 1, 4-diamino-n-butane, 1, 6-diamino-n-hexane, and the like.

As specific examples of the monomer represented by the general formula (11) and salts thereof, compounds 1 to 11 and salts thereof are preferably exemplified.

The hydrophilic monomer represented by the general formula (11) can be synthesized, for example, by esterification reaction or amidation reaction using (meth) acrylic acid, (meth) acrylic acid chloride as shown in the above reaction formulas (1) and (2).

As described above, in the present invention, as the hydrophilic polymer, the above-mentioned general formulae (2), (9), (10) and (11) can be used.

[ 3] Water-soluble copolymer

The (PEG-23 methoxymethacrylate/diisostearic acid glyceryl methacrylate) copolymer mainly contains, as the structural unit (g), a structural unit (g) derived from a hydrophobic monomer in which R24 and R25 are 16-methylpentadecanoyl group among the hydrophobic monomers represented by the general formula (15).

And a structural unit (h) derived from a hydrophilic monomer represented by the general formula (2) wherein R4 is a methyl group, R5 is a vinyl group, R6 is a methyl group, and n is 23.

In the present invention, the proportion of the structural unit (g) in the water-soluble copolymer in the total structural units is preferably 1 to 50% by mass, more preferably 5 to 40% by mass, and 10 to 30% by mass.

By setting the proportion of the structural unit (g) in the water-soluble copolymer in the above range, a sunscreen cosmetic having excellent moisturizing feeling and further reduced tightening feeling can be provided.

In the present invention, the proportion of the structural unit (h) in the water-soluble copolymer to the total structural units is preferably 50 to 99% by mass, more preferably 60 to 95% by mass, and 70 to 90% by mass.

By setting the proportion of the structural unit (h) in the water-soluble copolymer in the above range, a sunscreen cosmetic having excellent moisturizing feeling and further reduced tightening feeling can be provided.

In the present invention, the mass ratio of the structural unit (g) and the structural unit (h) constituting the water-soluble copolymer is preferably 5:95 to 50:50, more preferably 10:90 to 45:55, still more preferably 20:80 to 40:60, and still more preferably 25:75 to 35: 65.

The molar ratio of the structural unit (g) to the structural unit (h) constituting the water-soluble copolymer is preferably 8:92 to 62:38, more preferably 15:85 to 57:43, still more preferably 29:71 to 52:48, and still more preferably 35:65 to 46: 54.

By setting the mass ratio and the molar ratio of the structural unit (g) and the structural unit (h) in the water-soluble copolymer to the above ranges, the feeling of use of the sunscreen cosmetic can be further improved.

The content of the water-soluble copolymer is not particularly limited, but is usually 0.001 to 15% by mass, preferably 0.01 to 10% by mass.

<2> component (B) … polyglycerin fatty acid ester

The sunscreen cosmetic composition of the present invention is characterized by comprising, as component (B), a polyglycerol fatty acid ester obtained by ester-condensing 1-molecule polyglycerol having a polymerization degree of 10 and 2-5 molecules of a fatty acid having 16 or more carbon atoms.

The polyglycerin fatty acid ester constituting the component (B) may have a branched fatty acid having 16 or more carbon atoms and may be saturated or unsaturated.

Oleic acid and isostearic acid may be preferably exemplified.

The number of the fatty acid molecules bonded to 1 molecule of the polyglycerol ester may be 2 to 5, and preferably 5 molecules.

In the present invention, the component (B) is particularly preferably polycarbonate pentastearate-10.

The content of the polyglycerin fatty acid ester as the component (B) may be usually 0.1 to 10% by mass.

From the viewpoint of improving the emulsion stability, the content of the component (B) is 0.3% by mass or more, more preferably 0.5% by mass or more, and still more preferably 0.7% by mass or more.

From the viewpoint of suppressing the stickiness, the content of the component (B) is preferably 7% by mass or less, more preferably 5% by mass or less, and further preferably 3% by mass or less.

<3> component (C) … Ionic surfactant

The sunscreen cosmetic of the present invention contains an ionic surfactant as the component (C). The ionic surfactant is not particularly limited as long as it is used in cosmetics, and any anionic surfactant, cationic surfactant, or amphoteric surfactant can be used.

Examples of the anionic surfactant include fatty acid soaps such as sodium fatty acid, potassium fatty acid, and triethanolamine fatty acid, and polyoxyethylene groups, polyoxyethylene groups such as sodium lauryl sulfate, potassium lauryl sulfate, and triethanolamine lauryl sulfate, polyoxyethylene groups such as alkyl sulfate ester salts, acyl lactate salts, and polyoxyethylene groups such as sodium lauryl phosphate, potassium lauryl phosphate, and triethanolamine lauryl phosphate, and alkyl phosphate ester salts and sulfosuccinic acid alkyl ester salts are preferable.

Examples of the cationic surfactant include: alkyltrimethylammonium salts, alkylpyridinium salts, distearyldimethylammonium chloride, poly (N, N' -dimethyl-3, 5-methylenepiperidinium chloride) chloride, alkyl quaternary ammonium salts, alkyl dimethylbenzyl ammonium salts, alkyl isoquinolinium salts, dialkyl morpholine salts, POE-alkylamines, alkylamine salts, polyamine fatty acid derivatives, pentanol fatty acid derivatives, benzalkonium chloride, benzethonium chloride, and the like.

Among the above surfactants, as the component (C), an anionic surfactant is preferably used, and an acyl lactate is more preferably used.

The acyl lactate is preferably a sodium salt, and specifically, preferred examples thereof include: sodium lauroyl lactylate, sodium isostearoyl lactylate, sodium stearoyl lactylate, and the like.

The content of the ionic surfactant is not particularly limited, but is usually 0.01 to 2.0% by mass, and more preferably 0.1 to 1% by mass.

From the viewpoint of improving the emulsion stability, the content of the ionic surfactant is preferably 0.05% by mass or more, more preferably 0.07% by mass or more, and still more preferably 0.1% by mass or more.

From the viewpoint of suppressing stickiness, the content of the ionic surfactant is preferably 1.5% by mass or less, more preferably 1% by mass or less, and still more preferably 0.5% by mass or less.

<4> component (D) … ultraviolet scattering agent/ultraviolet absorber

The sunscreen cosmetic of the present invention contains an ultraviolet scattering agent and/or an ultraviolet absorber as the component (D).

The ultraviolet scattering agent refers to a fine-particle metal oxide having an action of scattering ultraviolet rays, and the type thereof is not particularly limited as long as it can be formulated with an emulsion type cosmetic. Examples of the metal oxide include: titanium dioxide, zinc oxide, zirconium oxide, cerium oxide, and the like.

The content of the ultraviolet scattering agent is not particularly limited, but is usually 0.01 to 20% by mass, preferably 0.1 to 15% by mass, and more preferably 1 to 10% by mass.

The ultraviolet scattering agent has a particle size called fine particles in this technical field, and for example, a primary particle size observed by an electron microscope is usually 5nm or more, preferably 10nm or more, and usually 100nm or less, preferably 80nm or less.

The ultraviolet scattering agent used in the present invention preferably contains at least one selected from the group consisting of fine particulate titanium dioxide and fine particulate zinc oxide because of its excellent ultraviolet scattering effect.

The ultraviolet scattering agent used in the present invention can be produced by a conventional method such as thermal decomposition of a salt of the corresponding metal in a gas phase, but since there are many commercially available products, the commercially available products can be used as they are. As such a commercially available product, specifically, as the fine particulate titanium dioxide, there can be mentioned: "MTY-110M 3S" (manufactured by Tayca Corp.), "MTY-02" (manufactured by Tayca Corp.), "MT-100 TV" (manufactured by Tayca Corp.), "MT-10 EX" (manufactured by Tayca Corp.), "MT-05" (manufactured by Tayca Corp.), "MT-100Z" (manufactured by Tayca Corp.), "MT-150 EX" (manufactured by Tayca Corp.), "MT-100 AQ" (manufactured by Tayca Corp.), "MT-100 WP" (manufactured by Tayca Corp.), "MT-100 SA" (manufactured by Tayca Corp.), "MT-500B" (manufactured by Tayca Corp.), "MT-500 SA" (manufactured by MT-500) (manufactured by Tayca.), "MT-500A" (manufactured by Tayca) (manufactured by Tayca Corp.), "MT-500) and" Tayca (manufactured by Tayca 600-100 "(manufactured by Tayca Corp.)," MT-100, "MT-500 SAS" (manufactured by Tayca corporation), "TIPAQUE CR-50" (manufactured by Shiyu industries, Ltd), "TIPAQUE TTO-M-1" (manufactured by Shiyu industries, Ltd), "TIPAQUE TTO-V4" (manufactured by Shiyu industries, Ltd), "ST-455" (manufactured by Titan industries, Ltd), "STT-65C-S" (manufactured by Titan industries, Ltd), "STT-30 EHS" (manufactured by Titan industries, Ltd), "Bayer TitanR-KB-1" (manufactured by Bayer) and the like.

Examples of the fine zinc oxide particles include: "MZY-300" (manufactured by Tayca Co., Ltd), "MZY-303S" (manufactured by Tayca Co., Ltd), "MZ-306X" (manufactured by Tayca Co., Ltd), "MZ-500" (manufactured by Tayca Co., Ltd), "MZY-505S" (manufactured by Tayca Co., Ltd), "MZ-506X" (manufactured by Tayca Co., Ltd), "MZ-510 HPSX" (manufactured by Tayca Co., Ltd), "WSX-MZ-700" (manufactured by Tayca Co., Ltd), "SAMT-UFZO-450" (manufactured by three well-formed chemical industries (Co., Ltd), "SAMT-UFZO-500" (manufactured by three well-formed chemical industries (Co., Ltd), "FZO-50" (manufactured by original Stone Co., Ltd), "Maxlight ZS-032 (manufactured by and electric engineering Co., Ltd)," MaxZS-032 (manufactured by Sho and Sho-0 (manufactured by Sho-Kogyo, and the like).

In the present invention, the surface of the ultraviolet scattering agent is preferably coated with an inorganic compound such as silica or alumina, or an organic compound such as sodium polyacrylate, fatty acid metal soap, or silicone resin.

The ultraviolet scattering agent is preferably water-dispersible. The sunscreen cosmetic of the present invention in this manner has an excellent ultraviolet protection function because the water-dispersible ultraviolet scattering agent is uniformly dispersed in the aqueous phase.

As the water-dispersible ultraviolet scattering agent, an ultraviolet scattering agent whose surface is coated with a hydrophilic compound can be preferably exemplified.

As such a water-dispersible ultraviolet scattering agent, an ultraviolet scattering agent surface-treated with sodium polyacrylate is preferable. The sunscreen cosmetic of the present invention comprising as the component (D) an ultraviolet scattering agent surface-treated with sodium polyacrylate has excellent dispersibility and excellent ultraviolet protection function.

The ultraviolet absorber is not particularly limited as long as it is an ultraviolet absorber that can be generally blended with an emulsion type cosmetic, and preferably includes an UV-A absorber that absorbs ultraviolet light having a wavelength (A region) of 320 to 400nm and a UV-B absorber that absorbs ultraviolet light having a wavelength (B region) of 290 to 320nm in order to absorb ultraviolet light having a wide wavelength.

The content of the ultraviolet absorber is not particularly limited, and is usually 0.01% by mass or more, preferably 0.1% by mass or more, and more preferably 1% by mass or more, and is usually 20% by mass or less, preferably 15% by mass or less, and more preferably 10% by mass or less.

Examples of the UV-a absorber include: 2-hydroxy-4-methoxybenzophenone, 2- (2 '-hydroxy-5' -methylphenyl) benzotriazole, 2-ethylhexyl dimethoxybenzylidenedioxoimidazolidinepropanoic acid, bis (heavy chain alkyl) triazine, methylenebisbenzotriazolyl tetramethylbutylphenol, hexyldiethylaminohydroxybenzoyl benzoate, t-butylmethoxydibenzoylmethane, and the like. Among them, hexyl diethylaminohydroxybenzoyl benzoate and tert-butyl methoxydibenzoylmethane are particularly preferable because of their excellent ultraviolet absorbability. Since these compounds are commercially available products, they can be used as they are. Specific examples of commercially available products include: "Uvinul A Plus Granular" (hexyldiethylaminohydroxybenzoylbenzoate, manufactured by BASF corporation), "Parsol 1789" (tert-butylmethoxybenzoylmethane, manufactured by DSM corporation).

The content of the UV-a absorber is usually 0.01% by mass or more, preferably 0.1% by mass or more, and is usually 5% by mass or less, preferably 3% by mass or less.

Specific examples of the UV-B absorber include: 2-ethylhexyl p-methoxycinnamate, 2-ethylhexyl 2-cyano-3, 3-diphenylacrylate, diethyl dimethylsiloxane diacrylate, 2,4, 6-trianilino-p- (carbo-2 '-ethylhexyl-1' -oxy) -1,3, 5-triazine, 2-hydroxy-4-methoxybenzophenone, ferric salicylate, octyl salicylate, and the like. Since these compounds are commercially available products, they can be used as they are. Specific examples of commercially available products include: "Uvinul MC 80" (2-ethylhexyl p-phenoxy cinnamate, manufactured by BASF), "Uvinul T150" (2,4, 6-trianilino-p- (carbo-2 '-ethylhexyl-1' -oxy) -1,3, 5-triazine, manufactured by BASF), "Uvinul M40" (2-hydroxy-4-methoxybenzophenone, manufactured by BASF), "Parsol SLX" (diethyl polydimethylsiloxane benzylidene malonate, manufactured by DSM), "Parsol 340" (2-ethylhexyl 2-cyano-3, 3-diphenylacrylate, manufactured by DSM), "Parsol HMS" (isopropyl salicylate, manufactured by DSM), "Parsol EMS" (octyl salicylate, manufactured by DSM).

The content of the UV-B absorber is usually 0.1% by mass or more, preferably 0.5% by mass or more, and usually 10% by mass or less, preferably 7% by mass or less.

<5> other composition

One or more kinds of oil agents may be used.

In the sunscreen cosmetic of the present invention, any additional component generally blended in cosmetics may be blended as long as the effect of the present invention is not impaired, examples of such additional component include humectants such as polyethylene glycol, glycerin, 1, 3-butylene glycol, erythritol, sorbitol, xylitol, maltitol, and the like, lower alcohols such as ethanol, antioxidants such as butylhydroxytoluene, tocopherol, phytic acid, and the like, antibacterial agents such as benzoic acid, salicylic acid, sorbic acid, alkyl parabens, hexachlorophene, organic acids such as acylsarcosine (e.g., sodium lauroyl sarcosinate), glutathione, citric acid, malic acid, tartaric acid, lactic acid, vitamin A and derivatives thereof, vitamin B6 hydrochloride, vitamin B6 tripalmitate, vitamin B6 dicaprylate, vitamin B2 and derivatives thereof, vitamin B12, vitamin B2 and derivatives thereof, vitamin B derivatives such as vitamin B, α -phenol, β -tocopherol, gamma-tocopherol, vitamin E acetate, vitamin D, vitamin B382 and derivatives thereof, preservatives such as thymol, ascorbic acid, benzoic acid, citric acid, benzoic acid, citric acid.

The sunscreen cosmetic of the present invention can be produced, for example, by the following method.

The oil agent is mixed with the component (B) and other oil phase components, and the mixture is heated and dissolved to prepare a mixture of the oil phase components. When the ultraviolet scattering agent (component (D)) is contained, the ultraviolet scattering agent is added to the mixture and dispersed with a dispersant.

Then, the aqueous phase component and the component (C) are mixed and heated, and then the mixture of the oil phase component is added and emulsified by using a homogenizer. After emulsification, the sunscreen cosmetic of the present invention can be produced by adding the component (a) and, if necessary, a water-dispersible ultraviolet scattering agent (component (D)) and cooling the mixture while stirring and mixing the mixture.

<1> coating film having sea-island structure

The sea-island structure is a structure in which two kinds of polymers that are not compatible with each other are phase-separated and a dispersed phase containing one polymer is dispersed in a continuous phase containing the other polymer. Then, the continuous phase in the sea-island structure is referred to as a sea phase, the dispersed phase is referred to as an island phase, and the particles of the dispersed phase are referred to as island particles.

The coating film of the present invention has a sea-island structure in which island particles comprising an amphiphilic copolymer are dispersed in a sea phase comprising an aqueous gel formed of a water-soluble polymer.

Then, the amphiphilic copolymer contained in the island particles has the structural unit (i) and the structural unit (j) as essential structural units.

The structural unit (i) is one or more structural units derived from a hydrophobic monomer, and the structural unit (j) is one or more structural units derived from a hydrophilic monomer.

The film of the present invention having such structural characteristics has a feeling of emulsion containing an oil agent regardless of whether or not the film is mainly composed of an aqueous component.

The coating film of the present invention will be described in detail below.

<1-1> island particle

In the present invention, the amphiphilic copolymer contained in the island particles of sea-island structure has the structural unit (i) derived from the hydrophobic monomer and the structural unit (j) derived from the hydrophilic monomer as essential structural units.

As the amphiphilic copolymer in the present invention, a copolymer containing a structural unit derived from a hydrophobic monomer and a hydrophilic monomer described in the following [ 1] and [ 2] is preferably used.

[ 1] hydrophobic monomer

In the present invention, it is preferable to use an amphiphilic copolymer (also referred to as an acrylic amphiphilic copolymer) containing, as an essential structural unit, one or two or more structural units derived from the hydrophobic monomer represented by the general formula (1), (7), or (8) (hereinafter, sometimes simply referred to as "structural unit (7), or the like").

(1-1) hydrophobic monomer represented by the general formula (7)

(1-2) hydrophobic monomer represented by the general formula (1) or (8)

Here, examples of the alkyl group represented by R1 and R16 include: methyl, ethyl, propyl, isopropyl, cyclopropyl, and the like. In the present invention, R3 is preferably a hydrogen atom or a methyl group.

[ 2] hydrophilic monomer

(2-1) polymerizable carboxylic acid

In the present invention, as the polymerizable carboxylic acid or a salt thereof, specifically, there can be exemplified: acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, and sodium, potassium, ammonium, amine salts thereof, and the like. Among them, acrylic acid, methacrylic acid and salts thereof are particularly preferable because of high polymerizability. When a structural unit derived from a salt of a polymerizable carboxylic acid is introduced into the water-soluble copolymer of the present invention, the polymerizable carboxylic acid may be previously formed into a salt and subjected to a polymerization reaction, or a structural unit derived from a polymerizable carboxylic acid may be introduced into an amphiphilic copolymer by a polymerization reaction and then neutralized with a base to form a salt.

(2-2) hydrophilic monomer represented by the general formula (2)

As the alkyl group represented by R4 in the general formula (2), there can be exemplified: methyl, ethyl, propyl, isopropyl, cyclopropyl. In the present invention, R6 is preferably a hydrogen atom or a methyl group.

In the general formula (2), n is in a numerical range of 6 to 40.

(2-3) hydrophilic monomer represented by the general formula (9)

< Synthesis method >

(2-4) hydrophilic monomer represented by the general formula (9)

Among the hydrophilic monomers represented by the general formula (10), the reducing sugar having a group whose hydrogen has been removed from the hydroxyl group at the 1-position of the reducing sugar represented by G — O "may be specifically exemplified by one or more selected from the group consisting of monosaccharides such as glucose, mannose, galactose, arabinose, xylose, and ribose, maltose, lactose, disaccharides such as cellobiose, trisaccharides such as maltotriose, and oligosaccharides such as maltooligosaccharides, among which one or more selected from the group consisting of glucose, galactose, arabinose, xylose, ribose, maltose, lactose, and cellobiose is preferable, and glucose is particularly preferable. Also, as the monomer represented by the general formula (10), glycosyloxyethyl methacrylate (hereinafter, abbreviated as GEMA) or glycosyloxyethyl acrylate (hereinafter, abbreviated as GEA) is preferable

(2-5) hydrophilic monomer represented by the general formula (11)

As the hydrophilic monomer of the present invention, a hydrophilic monomer represented by the above general formula (11) can be used.

The polyamine in the polyamine residue represented by R23 is an amine having two or more amino groups which may be substituted with an alkyl group in the same molecule, and specifically, the following are exemplified: diamines, triamines, tetramines or amines in which the hydrogen atoms of the amino groups are substituted by alkyl groups. Among them, diamines are preferable because the skin external preparation containing the obtained water-soluble copolymer is particularly excellent in feeling of use, and specific preferable examples thereof include: ethylenediamine, 1, 4-diamino-n-butane, 1, 6-diamino-n-hexane, and the like, because raw materials are easily obtained at the time of synthesis thereof.

The salt of the monomer represented by the general formula (11) is not particularly limited, and specifically, there may be exemplified: sodium salt, potassium salt, ammonium salt, amine salt, etc. obtained by neutralizing an acid moiety with an alkali, and hydrochloride, sulfate, nitrate, phosphate, citrate, oxalate, carbonate, etc. obtained by neutralizing an amino moiety with an acid. When the structural unit derived from the salt of the monomer represented by the general formula (11) is introduced into the amphipathic copolymer of the present invention, the monomer represented by the general formula (11) may be previously formed into a salt to be polymerized, or the structural unit derived from the monomer represented by the general formula (11) may be derived from the amphipathic copolymer by polymerization and then neutralized to form a salt.

The hydrophilic monomer represented by the general formula (11) can be synthesized, for example, by esterification reaction or amidation reaction using (meth) acrylic acid, (meth) acryloyl chloride as shown in the above reaction formulas (1) and (2).

In a preferred embodiment of the present invention, the amphiphilic copolymer comprises structural units (2) derived from said general formula (2).

[ 3] an amphiphilic copolymer

In the present invention, an acrylic amphiphilic copolymer having a structural unit (1) and a structural unit (2) is preferably used. Further, it is more preferable to use an acrylic amphiphilic copolymer having a structural unit (15) and a structural unit (2).

Among such acrylic amphiphilic copolymers, the (PEG-23 methoxy methacrylate/glyceryl diisostearate methacrylate) copolymer is particularly preferably used.

By containing such an acrylic amphiphilic copolymer, the moisture retention and flexibility of the coating film can be improved.

The (PEG-23 methoxymethacrylate/diisostearic acid glyceryl methacrylate) copolymer mainly contains, as the structural unit (i), a structural unit (i) derived from a hydrophobic monomer in which R24 and R25 are 16-methylpentadecanoyl group among the hydrophobic monomers represented by the general formula (15).

And a structural unit (j) derived from a hydrophilic monomer represented by the general formula (2) wherein R4 is a methyl group, R5 is a vinyl group, R6 is a methyl group, and n is 23.

As the amphiphilic copolymer in the present invention, in addition to the above-mentioned copolymers, conventional copolymers can be used. Specifically, as the amphiphilic copolymer, the conventional copolymers listed below can be used.

That is, the following conventional copolymers can be used: polyquaternium-51 (copolymer comprising 2-methacryloyloxyethyl phosphorylcholine and butyl methacrylate in a molar ratio of about 8: 2), polyquaternium-61 (copolymer comprising 2-methacryloyloxyethyl phosphorylcholine and stearyl methacrylate in a molar ratio of about 3: 7), (glyceryl methacrylate/stearyl methacrylate) copolymer (copolymer comprising glyceryl-N- (2-methacryloyloxyethyl) carbamate and stearyl methacrylate with a weight average molecular weight of about 40000) PEG/PPG/polytetramethylene glycol-8/5/3 glycerol, (hydrolyzed silk/PG propylmethylsilane glycol) crosspolymer (N- [ 2-hydroxy-3- [ 3- (hydroxymethyl) propoxy ] propyl ] hydrolyzed silk silicone glycol) A copolymer obtained by alkylation), (a copolymer of eicosanedioic acid/tetradecanedioic acid) polyglycerol-10 (an oligoester composed of a dibasic acid of eicosanedioic acid or tetradecanedioic acid and a polyglycerol having an average polymerization degree of 10), (a glycerol/oxybutylene) copolymer stearyl (a polymer having HLB of 18.0 obtained by simultaneous reaction and addition polymerization of glycidol and tetrahydrofuran with stearyl alcohol), polyquaternium-7 (a copolymer of dimethyldiallylammonium chloride and acrylamide), polyquaternium-39 (a terpolymer of acrylic acid, dimethyldiallylammonium chloride and acrylamide), and (a copolymer of sodium acrylate/acryloyldimethyltaurine) (a copolymer of sodium acrylate and acryloyldimethyltaurate), and the like.

Among them, it can be particularly preferably exemplified that: polyquaternium-51, polyquaternium-61, and (glyceryl methacrylate/stearyl methacrylate) copolymer.

In the present invention, the proportion of the structural unit (i) in the amphiphilic copolymer to the total structural units is preferably 1 to 50% by mass, more preferably 5 to 40% by mass, and 10 to 30% by mass.

By setting the ratio of the structural unit (i) in the amphipathic copolymer in the above range, the moisture retention and flexibility of the film of the present invention can be improved.

In the present invention, the proportion of the structural unit (j) in the amphiphilic copolymer to the total structural units is preferably 50 to 99% by mass, more preferably 60 to 95% by mass, and 70 to 90% by mass.

By setting the ratio of the structural unit (j) in the amphipathic copolymer in the above range, the moisture retention property and flexibility of the film of the present invention can be improved.

In the present invention, the mass ratio of the structural unit (i) to the structural unit (j) constituting the amphiphilic copolymer is preferably 5:95 to 50:50, more preferably 10:90 to 45:55, still more preferably 20:80 to 40:60, and still more preferably 25:75 to 35: 65.

When the mass ratio of the structural unit (i) to the structural unit (j) in the amphipathic copolymer is in the above range, the moisture retention property and flexibility of the film of the present invention can be improved.

In the present invention, the molar ratio of the structural unit (i) to the structural unit (j) constituting the amphipathic copolymer is preferably 8:92 to 62:38, more preferably 15:85 to 57:43, still more preferably 29:71 to 52:48, and still more preferably 35:65 to 46: 54.

By setting the molar ratio of the structural unit (i) to the structural unit (j) in the amphipathic copolymer to the above range, the moisture retention property and flexibility of the film of the present invention can be improved.

In the present invention, the average molecular weight of the amphiphilic copolymer is preferably 20000 to 110000, more preferably 20000 to 80000, more preferably 30000 to 80000, more preferably 40000 to 70000, even more preferably 50000 to 70000, even more preferably 57000 to 66000.

When the molecular weight of the amphiphilic copolymer is in the above range, the elasticity of the film of the present invention can be improved and the sticky feeling can be suppressed.

<1-2> sea phase

The island particles described above are dispersed in the sea phase of the aqueous gel. In the present invention, the aqueous gel is formed from a water-soluble polymer and/or a salt thereof and water hydrated with the water-soluble polymer.

The water-soluble polymer and/or a salt thereof forming the aqueous gel is not particularly limited as long as the phase containing the amphipathic copolymer can be dispersed as island particles, and preferably, one or two or more water-soluble polymers and/or salts thereof selected from the group consisting of acrylic water-soluble polymers, water-soluble polypeptides, and water-soluble polysaccharides can be used.

As the acrylic water-soluble polymer, a non-crosslinked acrylic polymer or a crosslinkable acrylic copolymer can be particularly preferably exemplified. Further, sodium polyacrylate may be preferably used as the non-crosslinked acrylic polymer, and sodium polyacrylate, (acrylic acid ester/alkyl acrylate (C10-30)) crosslinked polymer may be preferably used as the crosslinkable acrylic copolymer.

As the water-soluble polypeptide, sodium polyglutamate can be preferably exemplified.

As the water-soluble polysaccharide, xanthan gum and angelica dahurica polysaccharide can be preferably exemplified. Particular preference is given to using xanthan gum as water-soluble polysaccharide.

By using such a water-soluble polymer and/or a salt thereof, the moisture retention and flexibility of the film of the present invention can be improved.

<1-3> sea island structure

The film of the present invention has an island-in-sea structure in which an island phase containing an amphiphilic copolymer is dispersed in a sea phase containing an aqueous gel.

In the coating film having a sea-island structure of the present invention, the area ratio of the sea phase to the island phase is preferably 2:8 to 10:1, more preferably 3:7 to 9:1, and still more preferably 6:4 to 7: 3.

The coating film of the present invention having the sea phase and island phase area ratio in the above range has excellent elasticity, less tackiness, and excellent moisture retention and flexibility.

In a preferred embodiment of the present invention, the average minor axis-to-major axis ratio of the island particles is preferably 0.6 or more, more preferably 0.7 or more, further preferably 0.8 or more, and further preferably 0.9 or more.

By setting the average minor axis-to-major axis ratio of the island particles in the above range, the moisture retention and flexibility of the film of the present invention can be improved.

Further, the average minor axis-major axis ratio can be measured by observing the composition with a microscope. Specifically, the composition can be observed with a microscope, and the ratio of the minor axis to the major axis of 100 island particles can be measured and added and averaged.

In a preferred embodiment of the present invention, the percentage of island particles having a minor-axis-to-major-axis ratio of less than 0.6, more preferably less than 0.7, and still more preferably less than 0.8 among all the island particles contained in the coating film is 10% or less.

In a more preferred embodiment of the present invention, the percentage of island particles having a ratio of the minor axis to the major axis of less than 0.8 among all the island particles contained in the composition is 5% or less, more preferably 1% or less.

The coating film of the present invention of this embodiment has more excellent moisture retention and flexibility.

In a preferred embodiment of the present invention, the island particles having an average particle diameter of 0.5 to 10 μm, more preferably 1 to 5 μm, have a number particle size distribution of 80% or more.

In a more preferred embodiment of the present invention, the island particles having an average particle diameter of 1 to 5 μm have a number particle size distribution of 85% or more, more preferably 90% or more.

By setting the number particle size distribution of the island particles having such a small particle diameter to the above range, the moisture retention and flexibility of the film of the present invention can be further improved.

The average particle diameter of the island particles can be measured by observing the composition with a microscope. Specifically, the island particles can be obtained by measuring the major axis and the minor axis of the island particles by observing the composition under a microscope and then adding and averaging the measured values.

The film of the present invention may contain any component generally used in skin external preparations. Examples of such components include: oils and waxes, hydrocarbons, higher fatty acids, higher alcohols, synthetic ester oils, silicone oils, surfactants, polyols, moisturizing ingredients, tackifiers, powders, inorganic pigments, organic powders, ultraviolet absorbers, lower alcohols, vitamins, and polymers having a structure similar to living bodies.

Examples of the oil and wax include: macadamia nut oil, avocado oil, corn oil, olive oil, rapeseed oil, sesame oil, castor oil, safflower oil, cottonseed oil, jojoba oil, coconut oil, palm oil, liquid lanolin, hardened coconut oil, hardened oil, cut wax, hydrogenated castor oil, beeswax, candelilla wax, carnauba wax, rock and field wax, lanolin, reduced lanolin, hard lanolin, jojoba wax and the like.

Examples of the hydrocarbons include: fluid paraffin, squalane, pristane, ceresin, paraffin, ceresin, vaseline, microcrystalline wax, etc.

Examples of the higher fatty acids include: oleic acid, isostearic acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, undecylenic acid, and the like.

Examples of the higher alcohols include: cetyl alcohol, stearyl alcohol, isostearyl alcohol, behenyl alcohol, octyldodecanol, myristyl alcohol, cetostearyl alcohol, and the like.

Examples of the synthetic ester oils include: cetyl isooctanoate, isopropyl myristate, hexyldecyl isostearate, diisopropyl adipate, di-2-ethylhexyl sebacate, cetyl lactate, diisostearyl malate, ethylene glycol di-2-ethylhexanoate, neopentyl glycol didecanoate, glycerol di-2-heptylundecanoate, glycerol tri-2-ethylhexanoate, trimethylolpropane triisostearate, pentane tetra-2-ethylhexanoate, and the like.

Examples of the silicon-based oil agent include: chain polysiloxanes such as dimethylpolysiloxane, methylphenylpolysiloxane, and diphenylpolysiloxane, cyclic polysiloxanes such as octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane, modified polysiloxanes such as amino-modified polysiloxanes, polyether-modified polysiloxanes, alkyl-modified polysiloxanes, and fluorine-modified polysiloxanes, and the like.

The surfactant may be an anionic surfactant or a nonionic surfactant.

Examples of the anionic surfactants include: fatty acid soaps (sodium laurate, sodium palmitate, etc.), potassium lauryl sulfate, triethanolamine alkyl sulfate, etc.

Examples of the nonionic surfactant include: sorbitol fatty acid esters (sorbitan monostearate, sorbitan sesquioleate, etc.), glycerin fatty acids (glycerin monostearate, etc.), propylene glycol fatty acid esters (propylene glycol monostearate, etc.), hardened castor oil derivatives, glycerin alkyl ethers, POE sorbitan fatty acid esters (POE sorbitan monooleate, polyoxyethylene sorbitan monostearate, etc.), POE sorbitol fatty acid esters (POE-sorbitol monolaurate, etc.), POE glycerin fatty acid esters (POE-glycerin monoisostearate, etc.), POE fatty acid esters (polyethylene glycol monooleate, POE distearate, etc.), POE alkyl ethers (POE 2-octyldodecyl ether, etc.), POE alkylphenyl ethers (POE nonylphenyl ether, etc.), pluronic (プルロニック) -type, etc, POE-POP alkyl ethers (POE-POP 2-decyltetradecyl ether, etc.), TELONIKE (テトロニック) -type, POE castor oil-hardened castor oil derivatives (POE castor oil, POE hardened castor oil, etc.), sucrose fatty acid esters, alkyl glucosides, etc.

Examples of the polyhydric alcohols include: polyethylene glycol, erythritol, xylitol, propylene glycol, dipropylene glycol, isoprene glycol, 1, 2-pentanediol, 2, 4-hexanediol, 1, 2-octanediol, and the like.

Examples of the moisture-retaining component include: sodium pyrrolidone carboxylate, lactic acid, sodium lactate, and the like.

Examples of the tackifier include: guar gum, quince seed, carrageenan, galactan, gum arabic, pectin, mannan, starch, xanthan gum, curdlan, methylcellulose, hydroxyethyl cellulose, carboxymethyl cellulose, methylhydroxypropyl cellulose, chondroitin sulfate, dermatan sulfate, glycogen, heparan sulfate, hyaluronic acid, sodium hyaluronate, tragacanth gum, keratan sulfate, chondroitin, mucin sulfate, hydroxyethyl guar gum, carboxymethyl guar gum, dextran, caro sulfate, locust bean gum, dextran succinate, carboxyformic acid, chitin, chitosan, carboxymethyl chitin, agar, polyvinyl alcohol, polyvinylpyrrolidone, carboxyvinyl polymer, sodium polyacrylate, polyethylene glycol, bentonite, and the like.

Examples of the powder include: mica, talc, kaolin, synthetic mica, calcium carbonate, magnesium carbonate, anhydrous silicic acid (silica), alumina, barium sulfate, etc., which may be surface-treated.

Examples of the inorganic pigments include: can be used for treating surface red iron oxide, yellow iron oxide, black iron oxide, cobalt oxide, ultramarine, iron blue, titanium oxide, zinc oxide, etc

Examples of the organic pigments include: pearl agents such as titanium mica, fish phosphorus foil, bismuth oxychloride, etc., which can be treated on the surface, red 202, red 228, red 226, yellow 4, blue 404, yellow 5, red 505, red 230, red 223, orange 201, red 213, yellow 204, yellow 203, blue 1, green 201, purple 201, red 204, etc., which can be laked.

Examples of the organic powder include: polyethylene powder, polymethyl methacrylate, nylon powder, organopolysiloxane elastomer, and the like.

Examples of the ultraviolet absorber include: p-aminobenzoic acid type ultraviolet absorbers, anthranilic acid type ultraviolet absorbers, salicylic acid type ultraviolet absorbers, cinnamic acid type ultraviolet absorbers, benzophenone type ultraviolet absorbers, sugar type ultraviolet absorbers, 2- (2' -hydroxy-5 ' -tert-octylphenyl) benzotriazole, 4-methoxy-4 ' -tert-butyldibenzoylmethane, and the like.

Examples of the lower alcohols include: ethanol, isopropanol, phenoxyethanol, and the like.

Preferred examples of the vitamins include vitamin A or a derivative thereof, vitamin B6 hydrochloride, vitamin B6 tripalmitate, vitamin B6 dicaprylate, vitamin B2 or a derivative thereof, vitamin B12, vitamin B15 or a vitamin B derivative thereof, vitamin E compounds such as α -tocopherol, β -tocopherol, gamma-tocopherol and vitamin E acetate, vitamin D compounds, vitamin H, pantothenic acid, pantamine and pyrroloquinoline quinone.

Examples of the polymer having a structure similar to a living body include: polymethacryllysine, polysanylethylmethacrylate, and the like.

In the present invention, the content of the oil agent such as oil/wax, hydrocarbon, higher fatty acid, higher alcohol, synthetic ester oil, silicone oil agent is preferably 10% by mass or less, more preferably 5% by mass or less, further preferably 2.5% by mass or less, further preferably 2% by mass or less, further preferably 1% by mass or less, further preferably 0.5% by mass or less.

In a preferred embodiment of the present invention, the oil agent is not contained.

The coating film having a sea-island structure of the present invention can exhibit a feeling of use in the form of an emulsion containing an oil agent, regardless of the aqueous component.

Therefore, the coating film having a sea-island structure of the present invention may be of an oil-free type.

In the present invention, the content of the surfactant is preferably 10% by mass or less, more preferably 5% by mass or less, further preferably 2.5% by mass or less, further preferably 2% by mass or less, further preferably 1% by mass or less, and further preferably 0.5% by mass or less.

In a preferred embodiment of the present invention, the surfactant is not contained.

The coating film of the present invention can form a stable sea-island structure without containing a surfactant.

Therefore, the coating film having a sea-island structure of the present invention may be a surfactant-free type.

<2> composition for forming coating film

The present invention also relates to a composition which can form the above-described covering film having an island structure of the present invention on the skin by being applied to the skin.

The composition of the present invention contains the above-mentioned amphiphilic copolymer, a water-soluble polymer and/or a salt thereof, and water.

By applying to the skin, water in the composition evaporates, and the amphipathic copolymer and the water-soluble polymer are phase-separated. As a result of this phase separation, the coating film of the present invention is formed on the skin. After the phase separation, water and the polyol in the composition are taken into an aqueous gel formed of the water-soluble polymer.

The composition of the present invention is described in further detail below. The composition of the present invention may be applied to the coating film of the present invention described in the item <1 >.

In the composition of the present invention, the content of the amphiphilic copolymer is preferably 0.01 to 10% by mass, more preferably 0.05 to 7% by mass, even more preferably 0.1 to 5% by mass, and even more preferably 0.5 to 3% by mass.

According to the composition of the present invention in which the content of the amphiphilic copolymer is in the above range, a coating film having excellent elasticity and low stickiness can be formed on the skin.

In the present invention, the water-soluble polymer is preferably present in an amount of 0.001 to 10% by mass, more preferably 0.005 to 5% by mass, even more preferably 0.01 to 1% by mass, and even more preferably 0.05 to 0.5% by mass, based on the total composition.

The composition of the present invention having the water-soluble polymer content in the above range can form a film having excellent moisture retention and flexibility on the skin.

In a preferred embodiment of the present invention, the mass ratio of the content of the water-soluble polymer to the content of the amphiphilic copolymer is preferably 1:100 to 1:2, more preferably 1:50 to 1:5, still more preferably 1:30 to 1:10, and still more preferably 1:25 to 1: 15.

The composition of the present invention having the content ratio by mass of the water-soluble polymer to the content of the amphiphilic copolymer in the above range can form a coating film having high uniformity.

In the present invention, it is preferable to include a polyol which promotes/inhibits separation of the sea phase from the island phase.

That is, in a preferred embodiment of the present invention, the aqueous gel and the amphiphilic copolymer are/is composed of a polyol which promotes phase separation (hereinafter also referred to as an accelerating polyol) and/or a polyol which inhibits phase separation (hereinafter also referred to as an inhibiting polyol). In particular, it is preferable to contain both the accelerating polyol and the inhibiting polyol.

According to the composition of the present invention containing such a polyol, a coating film having a sea-island structure with high uniformity can be formed on the skin.

As the accelerating polyol, a polyol in which the cloud point of an aqueous solution is raised by mixing with the aqueous solution of a nonionic surfactant having a polyether chain in a hydrophilic part can be preferably exemplified. As such accelerating polyol, 1, 3-butanediol and polyethylene glycol can be preferably exemplified.

By using such a polyol, a film having higher uniformity can be formed.

In the present invention, the content of the accelerating polyol in the entire composition of the present invention is preferably 0.1 to 30% by mass, more preferably 1 to 25% by mass, even more preferably 3 to 20% by mass, and even more preferably 5 to 15% by mass.

By setting the content of the accelerating polyol in the entire composition of the present invention to the above range, the uniformity of the coating film to be formed can be further improved.

As the suppressive polyol, a polyol in which the cloud point of an aqueous solution is lowered by mixing with the aqueous solution of a nonionic surfactant having a polyether chain in a hydrophilic part can be preferably exemplified. Preferred examples of such inhibitory polyols include: glycerol, diglycerol, sorbitol, and maltitol.

By using such a polyol, a coating film having higher uniformity can be formed.

The content of the inhibitory polyol in the entire composition of the present invention is preferably 0.5 to 30% by mass, more preferably 1 to 25% by mass, even more preferably 5 to 20% by mass, and even more preferably 8 to 15% by mass.

By setting the content of the accelerating polyol to the above range, the uniformity of the film to be formed can be further improved.

In the present invention, the cloud point is a temperature at which a phase separation occurs due to a temperature change in a transparent or translucent liquid and the resultant phase separation becomes opaque, and particularly a temperature at which a solute starts to separate from water when an aqueous solution of a nonionic surfactant is heated.

Whether the cloud point of an aqueous solution of a nonionic surfactant having a polyether chain in a hydrophilic portion is increased or decreased can be confirmed specifically by the following method.

An aqueous solution of a nonionic surfactant having a polyether chain in a hydrophilic portion was heated, and the temperature at which the aqueous solution started to become cloudy, that is, the cloud point was recorded. Then, a polyol was added to the aqueous solution and mixed, and the resulting mixture was warmed, and the cloud point was recorded as well.

When the cloud point of the aqueous solution after the addition was higher than that of the aqueous solution before the addition of the polyol, the added polyol was evaluated as "causing the cloud point of the aqueous solution to rise".

Conversely, when the cloud point of the aqueous solution after the addition is lower than that of the aqueous solution before the addition of the polyol, it is evaluated that the polyol added "lowers the cloud point of the aqueous solution".

As the nonionic surfactant having a polyether chain in a hydrophilic portion used for the measurement of the cloud point, a nonionic surfactant having polyethylene glycol in a hydrophilic portion can be preferably exemplified.

As such a nonionic surfactant, specifically, there can be exemplified: polyoxyethylene n-butyl ether (POE (n) OE, n ═ 3,10,15,20,23) (manufactured by japan Emulsion, POE (20) sorbitan monostearate (manufactured by tokho chemical), POE (20) glycerol monostearate (manufactured by rikawa chemical), POE (10) monostearate (manufactured by solar light Chemicals), and polyglycerol (6) monolaurate (manufactured by saka chemical).

In the present invention, the mass ratio of the accelerating polyol to the inhibiting polyol is preferably 10:1 to 1:10, more preferably 6:1 to 1:5, even more preferably 4:1 to 1:3, even more preferably 3.5:1 to 1:2.5, and even more preferably 1.6:1 to 1: 1.

By setting the mass ratio of the accelerating polyol to the inhibiting polyol to the above range, a composition capable of forming a coating film having a sea-island structure with high stability can be provided.

In the present invention, the mass ratio of the total mass of the accelerating polyol and the inhibiting polyol to the content of the amphiphilic copolymer is preferably 5:1 to 20:1, more preferably 7:1 to 15:1, and still more preferably 8:1 to 12: 1.

By making the mass ratio of the total mass of the accelerating polyol and the inhibiting polyol to the amphiphilic copolymer within the above range, a composition having a sea-island structure with high stability can be provided.

In the present invention, the ratio of the total mass of the accelerating polyol and the inhibiting polyol to the total mass of the amphiphilic copolymer and the water-soluble polymer is 5:1 to 20:1, more preferably 7:1 to 15:1, and still more preferably 8:1 to 12: 1.

In a preferred embodiment of the present invention, the content of the accelerating polyol in the total amount of the three components of the accelerating polyol, the inhibiting polyol and the amphiphilic copolymer is preferably 10 to 80% by mass, more preferably 20 to 70% by mass, even more preferably 30 to 70% by mass, even more preferably 40 to 60% by mass, and even more preferably 40 to 55% by mass.

When the content of the accelerating polyol is in the above range, precipitation in the composition can be prevented, and the stability of the composition can be improved. Further, the composition of this embodiment can form a coating film excellent in moisture retention and flexibility.

In a preferred embodiment of the present invention, the content of the inhibitory polyol in the total amount of the three components, i.e., the accelerating polyol, the inhibitory polyol and the amphiphilic copolymer, is preferably 10 to 80% by mass, more preferably 20 to 70% by mass, even more preferably 30 to 60% by mass, and even more preferably 35 to 50% by mass.

When the content of the inhibiting polyol is in the above range, precipitation in the composition can be prevented, and the stability of the composition can be improved. Further, the composition of this embodiment can form a coating film excellent in moisture retention and flexibility.

In a preferred embodiment of the present invention, the content of the amphiphilic copolymer in the total amount of the three components, i.e., the accelerating polyol, the inhibiting polyol and the amphiphilic copolymer, is preferably 1 to 50% by mass, more preferably 3 to 20% by mass, even more preferably 5 to 15% by mass, and even more preferably 8 to 12% by mass.

By making the content of the amphiphilic copolymer in the range, a composition having a tackiness that is easily spread on the skin can be provided. Further, the composition of this embodiment can form a coating film excellent in moisture retention and flexibility.

In a preferred embodiment of the present invention, the total amount of the three components, i.e., the accelerating polyol, the inhibiting polyol and the amphiphilic copolymer, is 20 to 70% by mass, the inhibiting polyol is 20 to 70% by mass and the amphiphilic copolymer is 5 to 20% by mass.

By employing such an embodiment, the stability of the composition can be improved.

Further, by adjusting the content of the accelerating polyol, the content of the inhibiting polyol and the content of the amphiphilic copolymer in the total amount of the accelerating polyol, the inhibiting polyol and the amphiphilic copolymer to the above ranges, the major-minor axis ratio and the average particle diameter of the island particles in the coating film formed from the composition of the present invention can be adjusted to the preferable ranges described in the item <1-3 >.

The composition of the present invention can be produced by mixing the raw materials under stirring at normal temperature.

The content of water in the composition of the present invention is preferably 60 to 99% by mass, more preferably 70 to 95% by mass, and still more preferably 80 to 90% by mass.

By applying the composition of the present invention having a water content in the range described above to the skin, the coating film of the present invention can be easily formed on the skin.

<3> method for forming coating film on skin

The present invention also relates to a method of forming the above-described film of the present invention on skin.

The method of the invention is characterized by applying the composition of the invention to the skin. The water in the composition is evaporated by coating, so that the aqueous gel formed by the water-soluble polymer and the amphiphilic copolymer are phase-separated. As a result of this phase separation, the coating film having the sea-island structure of the present invention can be formed on the skin.

In the present invention, it is preferable to use an aqueous solution containing a polyol which promotes phase separation of the amphipathic copolymer and the hydrogel and/or a polyol which inhibits phase separation of the aqueous gel and the amphipathic copolymer.

By using such an aqueous solution, a film having excellent uniformity can be formed on the skin.

In the composition of the present invention, the content of the oil agent such as oil/wax, hydrocarbon, higher fatty acid, higher alcohol, synthetic ester oil, and silicone oil is preferably 2% by mass or less, more preferably 1% by mass or less, and still more preferably 0.5% by mass or less.

In the composition of the present invention, the content of the surfactant is preferably 2% by mass or less, more preferably 1% by mass or less, and still more preferably 0.5% by mass or less.

Preferred embodiments of the composition and the coating film in the method of the present invention are as described in the above items <1> and <2 >.

Examples

<1> Synthesis of hydrophobic monomers

An example of producing the hydrophobic monomer represented by the general formula (1) is shown below.

Production example 1 Synthesis of Glycerol monoacrylate

A3L four-necked flask was charged with 79.5g of R) - (+) -2, 2-dimethyl-1, 3-dioxolan-4-methanol (manufactured by Tokyo chemical industry Co., Ltd.), 258.0g of methyl acrylate and 3.7g of tetramethoxytitanium. Then, the reaction solution was stirred, and ester exchange reaction was carried out at 105 to 110 ℃ for 2.5 hours while introducing nitrogen gas into the solution. After the reaction was completed, the acrylic ketal 1 (intermediate 1) was obtained by fractional distillation using reduced pressure distillation.

A3L four-necked flask was charged with 90.2g of water, 28.4ml of cation exchange resin RCP 160M (manufactured by Mitsubishi chemical corporation), and 94.2g of intermediate 1. Then, the reaction solution was stirred, and a ketal was deketonized at 24 ℃ for 27 hours while introducing nitrogen gas into the solution. After completion of the reaction, the cation exchange resin was filtered from the reaction solution, and the filtered reaction solution was washed 6 times with 100ml of hexane to remove unreacted raw materials, and then 200ml of ethyl acetate was added to the water layer to extract the product. Then, ethyl acetate and water were distilled off from the ethyl acetate extract under reduced pressure (800Pa) at 40 ℃ or lower to obtain glycerol monoacrylate.

Production example 2 Synthesis of trimethylolpropane monoacrylate

Step (1): 145.7g of trimethylolpropane, 300mL of acetone, 3g of p-toluenesulfonic acid 1 hydrate and 300mL of petroleum ether were put into an eggplant-shaped flask equipped with a calcium tube, a cooling tube and a Dean-Stark trap, and the mixture was heated under reflux in an oil bath set at 50 ℃. After 12 hours, it was confirmed that no more moisture was newly generated, and the reaction mixture was cooled to room temperature. Then, 3g of sodium acetate was added, and after further stirring for 30 minutes, petroleum ether and acetone were distilled off by an evaporator. The crude product thus obtained was distilled under reduced pressure to obtain ketalized trimethylolpropane (intermediate 2).

Step (2): into a 3L four-necked flask were charged 104.8g of intermediate 2 obtained in step (1), 258.0g of methyl acrylate, and 3.7g of tetramethoxytitanium. Then, the reaction solution was stirred, and ester exchange reaction was carried out at 105 to 110 ℃ for 2.5 hours while introducing nitrogen gas into the solution. After the completion of the reaction, the acrylic ester of ketalized trimethylolpropane (intermediate 3) was obtained by fractional distillation under reduced pressure.

Step (3): A3L four-necked flask was charged with 90.2g of water, 28.4ml of cation exchange resin RCP 160M (manufactured by Mitsubishi chemical corporation), and 115.3g of intermediate 3 obtained in step (2). Then, the reaction solution was stirred, and a ketal was deketonized at 24 ℃ for 27 hours while introducing nitrogen gas into the solution. After completion of the reaction, the cation exchange resin was filtered from the reaction solution, and the filtered reaction solution was washed 6 times with 100ml of hexane to remove unreacted raw materials, and then 200ml of ethyl acetate was added to the water layer to extract the product. Then, ethyl acetate and water were distilled off from the ethyl acetate extract under reduced pressure (800Pa) at a temperature of less than 40 ℃ to obtain trimethylolpropane monoacrylate.

Production example 3 Synthesis of trimethylolpropane monomethacrylate

Trimethylolpropane monomethacrylate was synthesized in the same manner as in production example 2, except that the amounts of trimethylolpropane, methyl acrylate (acrylic acid ester), the intermediate obtained in step (1), and the intermediate obtained in step (2) in production example 2 were changed as shown in table 1. Table 1 shows the amounts of the trihydric alcohol and the trihydric alcohol charged, the intermediate obtained in step (1) and the intermediate charged, and the intermediate obtained in step (2) and the charged amount.

[ Table 1]

Production example 4 production example 1 of hydrophobic monomer represented by general formula (1)

28.4g of 16-methylheptadecanoic acid (manufactured by Sigma-Aldrich Co.), 35.7g of thionyl chloride (manufactured by Tokyo chemical industry Co., Ltd.) and 200ml of benzene were mixed with stirring in a reaction vessel equipped with a stirrer and a cooling tube. After refluxing for 4 hours while continuing stirring, purification was carried out by vacuum distillation to obtain 16-methylheptadecanoic acid chloride.

In a reaction vessel equipped with a stirrer, 16.0g of glycerol monomethacrylate ("BLEMMER GLM", manufactured by Nippon fat and oil Co., Ltd.) and 30.0g of triethylamine were dissolved in 300ml of tetrahydrofuran. The obtained solution was cooled in ice and stirred, and 60.6g of the 16-methylheptadecanoic acid chloride obtained above was dissolved in 100ml of tetrahydrofuran, and then added dropwise over 2 hours. After completion of the dropwise addition, the resulting white precipitate was filtered, and tetrahydrofuran and triethylamine were removed from the filtrate by using a rotary evaporator to obtain a product. It was confirmed by NMR measurement that the obtained compound was a hydrophobic monomer (hydrophobic monomer 1) of a structural unit necessary for deriving the copolymer of the present invention represented by the following formula (29).

Hydrophobic monomer 1

[ chemical formula 29]

Production example 5 production example 2 of hydrophobic monomer represented by general formula (1)

25.6g of 2-hexyldecanoic acid (manufactured by Sigma-Aldrich Co.), 35.7g of thionyl chloride (manufactured by Tokyo chemical industry Co., Ltd.) and 200ml of benzene were stirred and mixed in a reaction vessel equipped with a stirrer and a cooling tube. After refluxing for 4 hours while continuing stirring, purification was carried out by distillation under reduced pressure to obtain 2-hexyldecanoic acid chloride.

In a reaction vessel equipped with a stirrer, 16.0g of glycerol monomethacrylate ("BLEMMER GLM", manufactured by Nippon fat and oil Co., Ltd.) and 30.0g of triethylamine were dissolved in 300ml of tetrahydrofuran. The resulting solution was cooled in ice and stirred, and a solution prepared by dissolving 55.0g of the 2-hexyldecanoic acid chloride obtained above in 100ml of tetrahydrofuran was added dropwise over 2 hours. After completion of the dropwise addition, the resulting white precipitate was filtered, and tetrahydrofuran and triethylamine were removed from the filtrate by using a rotary evaporator to obtain a product. It was confirmed by NMR measurement that the obtained compound was a hydrophobic monomer (hydrophobic monomer 2) of a structural unit necessary for deriving the copolymer of the present invention represented by the following formula (30).

Hydrophobic monomer 2

[ chemical formula 30]

(production example 6) production example 3 of hydrophobic monomer represented by the general formula (1)

28.4g of 9-methylheptadecanoic acid (manufactured by Sigma-Aldrich Co.), 35.7g of thionyl chloride (manufactured by Tokyo chemical industry Co., Ltd.) and 200ml of benzene were mixed with stirring in a reaction vessel equipped with a stirrer and a cooling tube. After refluxing for 4 hours while continuing the stirring, the mixture was purified by vacuum distillation to obtain 9-methylheptadecanoic acid chloride.

In a reaction vessel equipped with a stirrer, 16.0g of glycerol monomethacrylate ("BLEMMER GLM", manufactured by Nippon fat and oil Co., Ltd.) and 30.0g of triethylamine were dissolved in 300ml of tetrahydrofuran. The obtained solution was cooled in ice and stirred, and a solution prepared by dissolving 60.6g of the 9-methylheptadecanoic acid chloride obtained above in 100ml of tetrahydrofuran was added dropwise over 2 hours. After completion of the dropwise addition, the resulting white precipitate was filtered, and tetrahydrofuran and triethylamine were removed from the filtrate by using a rotary evaporator to obtain a product. It was confirmed by NMR measurement that the obtained compound was a hydrophobic monomer (hydrophobic monomer 3) of a structural unit necessary for deriving the copolymer of the present invention represented by the following formula (31).

Hydrophobic monomer 3

[ chemical formula 31]

<2> Synthesis of copolymer of the present invention

(1) Synthesis of copolymers of example 1 and comparative example 1

24.0g of the hydrophobic monomer 1 (production example 4), 90.0g of methoxypolyethylene glycol (23) methacrylate (product name "BLEMMER PME-1000" manufactured by NOF corporation), 300ml of isopropyl alcohol, and 300ml of a phosphate buffer solution (pH6.8) (manufactured by Nacalai Tesque Co., Ltd.) were taken, and the mixture was stirred and mixed in a flask equipped with a nitrogen introduction tube, a condenser, and a stirring device. While stirring was continued, nitrogen substitution was performed for 1 hour. A solution of 2.0g of ammonium persulfate dissolved in 20ml of water was added thereto, and a reaction was carried out at 65 ℃ for 10 hours while continuing stirring (a reaction was carried out under the same conditions for 16 hours to synthesize a copolymer of comparative example 1). After the reaction was completed, the pH was adjusted to 7.0 using an aqueous sodium hydroxide solution, and isopropanol was removed using a rotary evaporator to obtain an aqueous solution of the copolymer of example 1 (an aqueous solution of the copolymer of comparative example 1 was obtained by treatment under the same conditions).

The weight average molecular weight (in terms of polystyrene) of the copolymer of example 1 was 61000 by GPC. And the mass ratio of the structural unit (a) to the structural unit (b) is about 3:7 when measured by NMR.

On the other hand, the copolymer of comparative example 1 had a weight average molecular weight of 122500 and a mass ratio of the structural unit (a) to the structural unit (b) of about 3: 7.

(2) Synthesis of copolymers of examples 2 to 8

Copolymers having the structures shown in table 2, weight average molecular weights, and molar ratios of the structural unit (a) and the structural unit (b) were synthesized in the same manner as in the above (1). The weight average molecular weight of the copolymer was adjusted by changing the reaction time. The molar ratio of the structural unit (a) to the structural unit (b) can be adjusted by adjusting the molar ratio of the charged amounts of the hydrophobic monomer and the hydrophilic monomer added to the reaction solution.

Examples 2 to 6 are copolymers synthesized using the hydrophobic monomer 1. Example 7 is a copolymer synthesized using the hydrophobic monomer 2, and example 8 is a copolymer synthesized using the hydrophobic monomer 3.

[ Table 2]

< test example 1>

A2 mass% aqueous solution of the copolymers of examples 1 to 6 and comparative example 1 was prepared. Each aqueous copolymer solution was applied to the skin of 3 professional functional evaluators, and the feeling of elasticity was evaluated according to the following criteria. Table 3 shows the results.

Sense of elasticity

◎. has very strong elasticity

○. has strong elasticity

△. has elasticity

X.less elastic

[ Table 3]

As shown in Table 3, when the copolymers of examples 1 to 6 and comparative example 1 having the same structure of the structural unit (a) were compared, the aqueous solutions of the copolymers of examples 1 to 6 had a stronger elastic feeling than the aqueous solution of the copolymer of comparative example 1. In particular, the copolymers of the invention of examples 1, 5 and 6 have a very strong elastic feel.

The above results show that a copolymer comprising a structural unit (a) and a structural unit (b) having a weight average molecular weight of 20000 to 110000, particularly preferably 57000 to 66000, has an excellent elastic feeling.

< test example 2>

The same method as in test example 1 was used to evaluate the elasticity of the copolymers of examples 7 and 8. As a result, it was found that the copolymers of examples 7 and 8 also had an elastic feeling.

This result shows that a copolymer having an elastic feeling can be obtained even if the structure of the structural unit (a) is variously changed.

< test example 3>

A gel-like cosmetic was prepared by adding 0.5 mass% of xanthan gum to a 2 mass% aqueous solution of the copolymer of example 1 or the copolymer of comparative example 1. The gel-like cosmetic was applied to the skin of 3 professional functional evaluators as in experimental example 1, and the non-sticky feeling, the elastic feeling, and the moisturizing feeling were evaluated. Evaluation was performed according to the following evaluation criteria, using as a criterion the feel of use when an emulsion (standard cosmetic) containing trimethylolpropane triisostearate was applied to the skin. Table 4 and fig. 1 show the average values of the evaluation values of 3 evaluators.

Evaluation criteria

4 points. better tactile sensation than standard cosmetic

3 Point. touch feeling to the same extent as that of standard cosmetic

2 Point. slightly inferior to the touch of a standard cosmetic

1 Point. is inferior to the touch of a standard cosmetic

0 Point. is considerably inferior to the touch of a standard cosmetic

[ Table 4]

As shown in table 4 and fig. 1, the gel-like cosmetic of example 1 was significantly more elastic than the gel-like cosmetic of comparative example 1, and was excellent in a non-sticky feeling and a moisturizing feeling.

The results show that a copolymer comprising a structural unit (a) and a structural unit (b) having a weight average molecular weight of 20000 to 110000 has excellent elastic feeling and also has excellent non-sticky feeling and moisturizing feeling.

The ingredients shown in tables 5 to 7 below were mixed under stirring to prepare an emulsion composition.

In this example, as the water-soluble copolymer as the emulsifier of the present invention, a (glyceryl diisostearate methacrylate/PEG-23 methoxymethacrylate) copolymer having an average molecular weight of 61000, which was obtained by copolymerizing glyceryl isostearate as a hydrophobic monomer and PEG-23 methoxymethacrylate as a hydrophilic monomer at a mass ratio of about 3:7, was used.

Further, as the water-soluble copolymer, a composition was produced using polyoxypropylene (polymerization degree 60) and PEG/PPG-60/11 glycerin (Adekanol M-3228), which is an ether of polyoxyethylene (average polymerization degree 11) and glycerin (comparative examples 2,4, and 6).

Furthermore, as a surfactant, polyoxyethylene hardened castor oil was used to produce emulsion compositions (comparative examples 3, 5, and 7).

[ Table 5]

The tables below show the values of X and Y in examples 9 to 31.

The unit of the Chinese medicament is mass%

FIG. 2 shows a 3-component phase diagram depicting the compounding ratio of (glyceryl diisostearate methacrylate/PEG-23 methoxymethacrylate) copolymer, squalane and water in examples 9-31.

[ Table 6]

The tables below show the values of X and Y in examples 32-62.

The unit of the Chinese medicament is mass%

FIG. 3 shows a 3-component phase diagram depicting the compounding ratios of (glyceryl diisostearate methacrylate/PEG-23 methoxy methacrylate) copolymer, glyceryl tri (caprylate/caprate) and water in examples 32-62.

[ Table 7]

The tables below show the values of X and Y in examples 63-89.

The unit of the Chinese medicament is mass%

FIG. 4 shows a 3-component phase diagram depicting the compounding ratio of (glyceryl diisostearate methacrylate/PEG-23 methoxy methacrylate) copolymer, dimethicone, and water in examples 63-89.

The emulsion compositions of examples 9 to 89 exhibited stable emulsion forms even after 3 months of storage at room temperature. That is, a stable emulsion composition can be produced using the (glyceryl diisostearate methacrylate/PEG-23 methoxymethacrylate) copolymer even when any one of squalane, which is a nonpolar hydrocarbon oil, glyceryl tri (caprylic/capric) ester, which is a polar hydrocarbon oil, and silicone oil is used.

On the other hand, the compositions of comparative examples 2,4 and 6, which contained the water-soluble copolymer, i.e., PEG/PPG-60/11 glycerin, were not emulsified even by stirring and mixing, and were completely separated into an oil phase and an aqueous phase immediately after the production.

This result shows that a stable emulsified composition can be produced using various oil agents according to the emulsifier of the present invention, i.e., the water-soluble copolymer.

As shown in tables 5 to 7, emulsion compositions can be prepared in any formulations having a content of the (glyceryl diisostearate methacrylate/PEG-23 methoxymethacrylate) copolymer of 1 to 30% by mass.

As shown in tables 5 to 7, emulsion compositions can be produced in any case where the oil phase content is 10 to 70% by mass.

The skin was coated with appropriate amounts of the compositions of examples 9 to 89 and comparative examples 3, 5 and 7. As a result, the emulsion compositions of examples 9 to 89 were less sticky and did not have a irritating sensation as compared with the emulsion compositions of comparative examples 3, 5 and 7.

This result shows that the emulsified composition emulsified by the water-soluble copolymer which is the emulsifier of the present invention has an excellent feeling of use as compared with a general emulsified composition emulsified by a surfactant.

In particular, the emulsion composition of the example in which the content of the (glyceryl diisostearate methacrylate/PEG-23 methoxymethacrylate) copolymer was 15 mass%, more preferably 1 mass% had more excellent feeling of use.

< production example 7>

The face washes of examples 90 to 92 and comparative examples 8 and 9 were produced according to the following formulations. That is, the components a and b were heated to 80 ℃ respectively, and b was added to a under stirring and stirred, followed by cooling, thereby obtaining a face wash.

Further, as the water-soluble copolymer, a copolymer (glyceryl diisostearate methacrylate/PEG-23 methoxymethacrylate) having an average molecular weight of 61000 obtained by copolymerizing glyceryl diisostearate methacrylate as a hydrophobic monomer and PEG-23 methoxymethacrylate as a hydrophilic monomer at a molar ratio of about 3:7 was used.

[ Table 8]

< test example 4>

A skilled evaluator washed the face with the face lotions of examples 90 to 92 and comparative examples 8 and 9, and evaluated the lather and the lather quality at the time of use, and the non-skin-tightness and non-stickiness after washing the face, according to the following evaluation criteria. Table 8 shows the results.

Foaming of

◎ DEG foaming very well

○. good foaming

△. weak foaming

Non-foaming

Quality of foam

◎ DEG very creamy foam

○. cream-like foam

△. less cream

X. is not a cream

No sense of tightness

◎. no tightness

○ DEG almost without tightness

△. has tight feeling

X. has strong tightness

Feeling of invisibility

◎ DEG tack-free feeling

○ DEG almost no sticky feeling

△. has sticky feeling

Strong sticky feeling

As shown in Table 8, the cleansing creams of comparative example 8 have a strong skin-tightening feeling after cleansing the face, while the cleansing creams of examples 90 to 92 have almost no tightening feeling after cleansing the face.

The results show that the skin tightness caused by fatty acid soaps is reduced with the (glyceryl diisostearate methacrylate/PEG-23 methoxymethacrylate) copolymer.

In addition, in the facial cleanser of comparative example 9 containing carboxymethylcellulose as a water-soluble polymer in place of the (glyceryl diisostearate methacrylate/PEG-23 methoxymethacrylate) copolymer, no favorable lathering was observed which is an advantage of the fatty acid soap. On the other hand, the face washes of examples 90 to 92 showed good foaming.

The results show that the (glyceryl diisostearate methacrylate/PEG-23 methoxymethacrylate) copolymer can reduce the skin-tightening feeling after use without inhibiting good foaming of the fatty acid soap.

Also, as shown in table 8, the facial cleansers of examples 91 and 92 showed superior foaming compared to the facial cleanser of comparative example 8.

As a result, it was found that the foaming of the fatty acid soap can be improved by adjusting the content of the (glyceryl diisostearate methacrylate/PEG-23 methoxymethacrylate) copolymer to 0.8 mass% or more.

As shown in table 8, the cleansing cream of comparative example 9 had a strong sticky feeling on the skin after cleansing. On the other hand, the face creams of examples 90 to 92 had almost no sticky feeling after washing.

The results show that the (glyceryl diisostearate methacrylate/PEG-23 methoxy methacrylate) copolymer can reduce the skin tightness after the skin cleansing cream is used without generating sticky feeling.

As shown in table 8, the facial cleansers of examples 90 and 91 were superior to the facial cleanser of example 92 in non-sticky feeling.

As a result, it was found that by setting the content of the (glyceryl diisostearate methacrylate/PEG-23 methoxymethacrylate) copolymer to 3 mass% or less, the skin-tightening feeling after the use of the skin cleansing cream could be reduced without generating sticky feeling.

< production example 8>

The ingredients shown in Table 9 were mixed under stirring to obtain gel creams of examples 93 to 96 and comparative examples 10 to 12.

[ Table 9]

< test example 5>

A skilled evaluator washed the skin with a gel cleansing cream as in test example 4, and evaluated the cleanliness, ease of spreading on the skin during use, and no skin tightness after washing the skin according to the following evaluation criteria (the evaluation criteria for no tightness are the same as in test example 4). Table 9 shows the results.

Cleanliness

◎. the cleaning power is very strong

○. high cleanliness

△. weak cleanliness

Very weak cleaning power

Easy spreadability on the skin

◎. very diffusive

○. easily dispersible

△. hard to diffuse

Very difficult to diffuse

As shown in Table 9, the gel cleansers of comparative examples 10 and 11 provided strong skin tightness after cleansing, while the cleansers of examples 93 to 96 provided little tightness after cleansing.

This result shows that the skin tightness caused by the nonionic surfactant is reduced by the (glyceryl diisostearate methacrylate/PEG-23 methoxymethacrylate) copolymer.

As shown in table 9, the gel creams of examples 94 and 95 have an excellent effect of reducing the skin tightness after use, compared with the gel cream of example 93.

As a result, it was found that the skin-tightening feeling after use can be more effectively reduced by setting the content of the (glyceryl diisostearate methacrylate/PEG-23 methoxymethacrylate) copolymer to 0.7 mass% or more.

As shown in table 9, the gel creams of examples 93 to 96 were superior in cleanliness to the gel creams of comparative examples 10 to 12.

The results show that the cleansing power of the skin cleansing milk containing the nonionic surfactant can be improved by using the (glyceryl diisostearate methacrylate/PEG-23 methoxy methacrylate) copolymer.

Moreover, the gel cleanser of example 95 was superior in cleanliness to the gel cleansers of examples 93 and 94.

As a result, it was found that the cleansing power of the skin cleansing milk containing the nonionic surfactant can be improved by setting the content of the (glyceryl diisostearate methacrylate/PEG-23 methoxymethacrylate) copolymer to 2 mass% or more.

As shown in table 9, the gel creams of example 94 are superior in spreadability on the skin compared with the gel creams of examples 93 and 95.

The results show that by setting the content of the (glyceryl diisostearate methacrylate/PEG-23 methoxymethyl methacrylate) copolymer to 0.6 to 3% by mass, the spreadability on the skin during use of the gel face wash can be improved.

The gel creams of example 91 and example 93 had the same nonionic surfactant content, but the types were different. However, as shown in table 9, both types of gel creams showed equivalent effects in terms of cleanliness, spreadability on the skin, and no feeling of tightness.

The results show that the advantageous effects obtained by incorporating the (glyceryl diisostearate methacrylate/PEG-23 methoxymethacrylate) copolymer in the skin cleansing milk are not limited by the type of surfactant contained in the skin cleansing milk.

The results of test examples 4 and 5 show that the skin tautness of the used skin cleanser according to the present invention can be reduced.

Further, the present invention has been made to show that the original advantageous effects of the skin cleansing cream can be reduced or enhanced without impairing the advantageous effects of good foaming, creamy foam quality, cleanliness, easy spreadability on the skin, and the like, and the feeling of tightness of the skin after use can be reduced.

< production example 9>

The oil-in-water sunscreen cosmetics of examples 98 to 103 and comparative examples 13 to 15 were prepared according to the formulation shown in Table 10 by the following method.

The titanium oxide particles (a) are mixed and dissolved by heating to prepare a mixture of oil phase components, and the titanium oxide particles are dispersed using a disperser.

Then, (a) was added to the heated (b), and emulsification was performed using a homogenizer. After emulsification, (c) and (d) were added, and the mixture was cooled while being stirred and mixed to produce a sunscreen cosmetic.

In this example, as the water-soluble copolymer of the component (a), a copolymer (glycerol diisostearate methacrylate/PEG-23 methoxymethacrylate) having an average molecular weight of 61000, which was obtained by copolymerizing glycerol diisostearate methacrylate as a hydrophobic monomer and PEG-23 methoxymethacrylate as a hydrophilic monomer at a molar ratio of about 3:7, was used.

Watch 10

< test example 6>

The oil-in-water sunscreen cosmetics of examples 97 to 102 and comparative examples 13 to 15 after the adjustment were evaluated for emulsion stability, non-sticky feeling during use, and moisturizing feeling according to the following criteria. Table 10 shows the results.

Emulsion stability (state after 1 month storage at room temperature)

◎. No oil phase separation was observed at all

○ ℃ almost no oil phase separation was observed

△. oil film is floated on the surface of the preparation

Clear observation of oil phase separation

Tack free property

◎. full sense of non-tackiness

○ DEG almost no sticky feeling

△. has sticky feeling

Very sticky feeling

Moisture retention feeling

◎ DEG moisture-keeping feeling is very strong

○. has strong moisturizing effect

△ DEG moisture-keeping feeling is weak

X.moisture-keeping feeling was very weak

As shown in Table 10, the oil-in-water type sunscreen cosmetics of examples 97 to 102 containing all the components (A) to (D) had good emulsion stability, non-sticky feeling and moisturizing feeling.

On the other hand, the sunscreen cosmetic of comparative example 13 containing no component (a) had a strong sticky feeling. Also, the sunscreen cosmetic of comparative example 14 not containing component (B) and the sunscreen cosmetic of comparative example 15 not containing component (C) had poor emulsion stability.

These results show that the oil-in-water type sunscreen cosmetic compositions containing the components (a) to (D) have excellent emulsion stability, non-stickiness, and moisturizing feeling.

As shown in table 10, the sunscreen cosmetic composition of example 97 containing sodium stearoyl lactylate as component (C) had superior emulsion stability compared to the sunscreen cosmetic composition of example 100 containing sodium cocoyl glyceryl sulfate as component (C).

As a result, it was found that the oil-in-water type sunscreen cosmetic composition containing sodium acyl lactate as component (C) had excellent emulsion stability.

As shown in table 10, the sunscreen cosmetic composition of example 97 containing polyglyceryl pentastearate-10 as the component (B) had excellent emulsion stability as compared with the sunscreen cosmetic composition of example 101 containing polyglyceryl tristearate-10 as the component (B).

As a result, it was found that the oil-in-water type sunscreen cosmetic composition containing polyglycerol pentastearate-10 as the component (B) had excellent emulsion stability.

As shown in table 10, the sunscreen cosmetic composition of example 97 containing the ultraviolet scattering agent containing sodium polyacrylate-coated titania fine particles as the component (D) had an excellent moisturizing effect as compared with the sunscreen cosmetic composition of example 102 containing no coated titania fine particles.

As a result, it was found that an oil-in-water sunscreen cosmetic composition containing, as component (D), an ultraviolet scattering agent surface-treated with sodium polyacrylate, that is, a water-dispersible ultraviolet scattering agent, had an excellent moisturizing feel.

Also, the sunscreen cosmetic composition of example 102 had excellent emulsion stability and non-sticky feeling, compared with the sunscreen cosmetic compositions of examples 98 and 99 in which the content of the component (B) was 0.3% by mass and 7% by mass, respectively.

As a result, the content of the component (B) is preferably 0.5% by mass or more from the viewpoint of improving emulsion stability, and is preferably 5% by mass or less from the viewpoint of suppressing stickiness.

Also, the sunscreen cosmetic composition of example 97 has excellent emulsion stability and non-sticky feeling compared with the sunscreen cosmetic compositions of examples 98 and 99 in which the content of the component (C) is 0.05% by mass and 1.5% by mass, respectively.

As a result, the content of the component (C) is preferably 0.07 mass% or more from the viewpoint of improving emulsion stability, and is preferably 1 mass% or less from the viewpoint of suppressing stickiness.

< production example 10>

As shown in table 11, the compositions of the present invention of examples 103 to 123 were prepared by fixing the content of xanthan gum and the amphiphilic copolymer and varying the content of 1, 3-butanediol (accelerating polyol) and glycerin (inhibiting polyol). The contents of 1, 3-butanediol and glycerol in the respective examples were adjusted in accordance with the total amount of xanthan gum and the amphiphilic copolymer as shown in the three-component phase diagram shown in FIG. 5.

As the amphiphilic copolymer, a copolymer (glyceryl diisostearate methacrylate/PEG-23 methoxymethacrylate) having an average molecular weight of 61000 obtained by copolymerizing glyceryl diisostearate methacrylate as a hydrophobic monomer and PEG-23 methoxymethacrylate as a hydrophilic monomer at a molar ratio of about 3:7 was used.

In the following test examples, a composition was prepared using a (glyceryl diisostearate methacrylate/PEG-23 methoxymethacrylate) copolymer to which a fluorescent probe "NBD-COCI" was chemically introduced in order to facilitate observation of the sea-island structure using a microscope.

[ Table 11]

Mass%

< test example 7> Observation of sea-island Structure of coating film

About 0.5g of the compositions of examples 103 to 123 was applied to a glass slide in a range of about 1.5cm by 1.5cm, and the slide was left at 40 ℃ for 3 days to evaporate water in the compositions, thereby forming a coating film on the glass slide. The structures of the coatings of examples 103 to 123 thus formed were observed using a confocal laser scanning microscope.

As a result, any composition forms an island in the sea structure. Fig. 6 shows a photomicrograph of the composition of examples 105, 106, 108, 111, 113, 114, 115, 119, 120, 122, 123.

As shown in FIG. 6, in the compositions of examples 115, 119 and 120, aggregation of island particles was observed, and island particles having an average particle diameter of more than 10 μm and island particles having a short axis-to-long axis ratio of less than 0.5 were observed in large amounts.

On the other hand, the compositions of examples 106 to 114 were found to have no aggregation of island particles, and the number particle size distribution of fine island particles having an average particle diameter of 1 to 5 μm was 80% or more.

This result shows that the composition in which the total amount of the water-soluble polymer and the amphiphilic copolymer is 15 mass% or less in the total amount of the components shown in the three-component phase diagram of fig. 5 is less likely to cause aggregation of island particles.

Further, no aggregation of island particles was observed, and the area ratio of the sea phase to the island phase in the coating films of examples 103 to 114, in which the number-particle size distribution of fine island particles having an average particle diameter of 1 to 5 μm was 80% or more, was 6:4 to 7: 3.

< test example 8> evaluation of Functionality

The coating film formed after applying the composition of example 103 to the skin was evaluated as 7-point full size in terms of moisture retention, elasticity, softness, fullness, softness, and stickiness by 48 evaluators as shown in fig. 7. Further, commercially available toner and emulsion were used as comparison targets. The results are shown in FIG. 7.

In addition, as the toner, a general toner mainly containing water, containing a polyhydric alcohol, a known water-soluble polymer, a preservative and an extract is used. As the emulsion, an oil-in-water type emulsion cosmetic containing mineral oil, macadamia nut oil, or the like as an oil phase component is used.

As shown in fig. 7, the film formed after applying the composition of example 103 to the skin was evaluated to be equal to or higher than the emulsion containing an oil agent in terms of the moisturizing feel, the elastic feel, the softness, the fullness, and the softness.

As shown in fig. 7, the coating film formed from the composition of example 103 was significantly less sticky than the emulsion and had the same degree of moisturization as the skin.

This result shows that the composition of the present invention can form a film having an emulsion-like touch feeling containing an oil agent on the skin regardless of the main use of the aqueous component. In particular, it was shown that the composition of the present invention can achieve a balance between moisture retention and softness which are difficult to achieve with cosmetics mainly containing water-soluble ingredients.

Further, the results show that the composition of the present invention is mainly composed of an aqueous component, and therefore, the composition has few drawbacks such as stickiness and the like found in cosmetics containing an oil agent.

< production example 11>

The compositions of the invention of examples 124 and 125 were adjusted according to the formulations of table 12.

[ Table 12]

(mass%)

The coating films formed from the compositions of examples 124 and 125 were observed with a microscope by the same method as in test example 8. As a result, no aggregation of island particles was observed, and the number particle size distribution of fine island particles having an average particle diameter of 1 to 5 μm was 80% or more, as in the case of the coatings of examples 103 to 114.

This result shows that a coating film having a good sea-island structure can be formed even when a polyquaternium-61 and a (glyceramidoethyl methacrylate/stearyl methacrylate) copolymer are used as the amphiphilic copolymer. That is, even when the kind of the amphiphilic copolymer having a structural unit derived from a hydrophobic monomer and a structural unit derived from a hydrophilic monomer is variously changed, a composition capable of forming a coating film having a sea-island structure can be prepared by combining with a water-soluble polymer and water.

Industrial applicability

The copolymer of the present invention for solving the first problem can be applied to cosmetics.

The present invention for solving the second problem can be applied to an emulsion cosmetic.

The present invention for solving the third and fourth problems can be applied to a facial cleanser.

The present invention for solving the fifth problem can be applied to a sunscreen cosmetic.

The present invention for solving the sixth problem can be applied to oil-free cosmetics.

Description of reference numerals:

1 example 103

2 example 104

3 example 105

4 example 106

5 example 107

6 example 108

7 example 109

8 example 110

9 example 111

10 example 112

11 example 113

12 examples 1143

13 example 115

14 examples 116

15 example 117

16 examples 118

17 example 119

18 examples 120

19 example 121

20 examples 122

21 example 123

Claims

1. A copolymer having, as essential structural units, one or more structural units (a) derived from a hydrophobic monomer represented by the following general formula (1) and one or more structural units (b) derived from a hydrophilic monomer represented by the following general formula (2), and having a weight average molecular weight of 20000 to 110000,

general formula (1)

[ chemical formula 1]

(1)

(in the general formula (1), R1 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R2 and R3 may be the same or different and represent an acyl group having 6 to 22 carbon atoms and having no cyclic structure and a branched chain, X represents a group obtained by removing an OH group from a triol).

General formula (2)

[ chemical formula 2]

(2)

(in the general formula (2), R4 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R5 represents an alkylene group having 2 to 4 carbon atoms which may have a hydroxyl group, R6 represents a hydrogen atom, an aromatic hydrocarbon group having 6 to 10 carbon atoms, an aliphatic hydrocarbon group having 1 to 14 carbon atoms or an acyl group having 1 to 12 carbon atoms. n represents an integer of 6 to 40).

2. The copolymer according to claim 1, wherein the mass ratio of the structural unit (a) to the structural unit (b) is 25:75 to 35: 65.

3. The copolymer of claim 1 or 2, wherein the molar ratio of the structural unit (a) to the structural unit (b) is from 35:65 to 46: 54.

4. The copolymer according to any one of claims 1 to 3, wherein the hydrophobic monomer is a hydrophobic monomer represented by the following general formula (3),

general formula (3)

[ chemical formula 3]

(3)

(in the general formula (3), R7 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R8 and R9 may be the same or different and represent an acyl group having 10 to 22 carbon atoms and a branched chain, which does not have a ring structure, or an acyl group having 6 to 9 carbon atoms and 2 or more branched chains, which does not have a ring structure, and Y represents a group obtained by removing an OH group from a triol).

5. The copolymer according to any one of claims 1 to 4, wherein the hydrophilic monomer is a hydrophilic monomer represented by the following general formula (4),

general formula (4)

[ chemical formula 4]

(4)

(in the general formula (4), R10 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R11 represents a hydrogen atom, an aromatic hydrocarbon group having 6 to 10 carbon atoms, an aliphatic hydrocarbon group having 1 to 14 carbon atoms or an acyl group having 1 to 12 carbon atoms, and m represents an integer of 6 to 40).

6. The copolymer according to any of claims 1 to 5, wherein the triol is selected from the group consisting of glycerol, trimethylolpropane, trimethylolethane.

7. The copolymer according to any one of claims 1 to 6, wherein the hydrophobic monomer is a compound represented by the following general formula (5),

general formula (5)

[ chemical formula 5]

(5)

(in the general formula (5), R12 and R13 may be the same or different and each represents an acyl group having 18 carbon atoms and having no cyclic structure and a branch).

8. The copolymer according to any one of claims 1 to 7, wherein the hydrophilic monomer is a hydrophilic monomer represented by the following general formula (6),

general formula (6)

[ chemical formula 6]

(6)

(in the general formula (6), I represents an integer of 6 to 40).

9. An external preparation for skin comprising the copolymer according to any one of claims 1 to 8.