WO2020235459A1 - Liquid oil-in-water composition - Google Patents

Abstract

The present invention addresses the problem of providing an oil-in-water emulsified composition that is liquid, but has excellent temporal viscosity stability and emulsification stability. The liquid oil-in-water composition according to the present invention as a solution to the problem is characterized by containing components (A)-(C): (A) a straight-chain saturated higher alcohol having 16 or more carbon atoms; (B) at least one anionic surfactant selected from the group consisting of sodium N-stearoyl-N-methyl taurate, and N-stearoyl-L-glutamic acid and salts thereof; and (C) a liquid oil, wherein the molar content ratio (A/B) of the component (A) to the component (B) is 2.8-6, the mass content ratio ((A+B)/C) of the total of the components (A) and (B) to the component (C) is 0.3-0.75, and the average emulsified particle size thereof is 160 nm or less.

Description

Liquid oil-in-water composition

The present invention relates to a liquid oil-in-water composition, and more particularly to a liquid oil-in-water composition which is liquid but has excellent viscosity stability and emulsion stability over time.

Conventionally, in the oil-in-water composition, when the content of the oil agent is increased, there is a problem that the emulsification stability is lowered due to separation and creaming over time. On the other hand, a technique of blending a hydrophilic anionic surfactant and a higher fatty alcohol in a predetermined molar ratio to form an α-gel having a gel transition temperature of 60 ° C. or higher (Patent Document 1), and higher alcohols An α-gel intermediate composition of a bicontinuous microemulsion phase consisting of a mixture of an anionic surfactant mixed at a predetermined molar ratio and a mixture of a water-soluble solvent having a specific IOB value and water at a predetermined mass ratio. (Patent Document 2), such as a technique for inducing α-gel formation by adding warm oil to this composition, then adding water and stirring (Patent Document 2), to improve emulsion stability by using α-gel. Attempts have been made to achieve this.

α-gel is one of the self-assembling bodies formed by amphipathic substances. It is located between the solid hydrated crystal (core gel) and the lamellar liquid crystal, and a large amount of water is allowed between the hydrophilic groups while maintaining the crystalline state. It is in a held state. Crystals that can hardly hold water, such as core gel, are in a state where the molecules themselves are tilted and packed more densely, whereas in lamellar liquid crystal, the structure of the bilayer liquid crystal is rich in fluidity and is in a liquid state, so many Can hold water. Similar to lamellar liquid crystal, α-gel has surfactants arranged in layers, but since it is regularly packed in hexagonal crystals, it retains rotational motion, but it has less hydrophobic group mobility than lamellar liquid crystal. , The movement of molecules is controlled. When the difference in motility based on such a structure is observed by differential scanning calorimetry (DSC) or the like, heat transfer can be observed as a gel-liquid crystal phase transition.

However, since the α-gel is an intermediate phase between the lamellar liquid crystal and the core gel, it is usually unstable, and the viscosity of the α-gel-containing oil-in-water emulsified composition obtained by the techniques of Patent Documents 1 and 2 also increases with time. In some cases, the viscosity stability was lacking. Further, the techniques of Patent Documents 1 and 2 impart emulsification stability based on the thickening action of α-gel, and since the viscosity becomes relatively high immediately after production, it is applicable to liquid cosmetics such as lotion. It was difficult to apply the technology.

Japanese Unexamined Patent Publication No. 2001-348325 Japanese Unexamined Patent Publication No. 2016-14011

J.Soc.Cosmet.Chem.Jpn.30 (3) 310-320 (1996) Food Biophysics, September 2012, Volume 7, Issue 3, pp 227-235 J.Soc.Cosmet.Chem.Jpn.44 (2) 103-117 (2010)

An object of the present invention is to provide an oil-in-water emulsification composition which is liquid but has excellent viscosity stability and emulsion stability over time.

As a result of diligent research to solve the above problems, the present inventors have specified specific N-stearoyl-N-methyltaurine sodium or N-stearoyl-L-glutamic acid and salts thereof with respect to the linear saturated higher alcohol. By adjusting the particle size of the emulsified droplets formed to 160 nm or less after combining an anionic surfactant in a predetermined amount, the liquid properties are maintained for a long period of time after production without thickening over time. At the same time, they have found that a good emulsified state can be stably maintained without causing creaming or separation, and have completed the present invention.

That is, the present invention describes the following components (A) to (C);
(A) Linear saturated higher alcohol having 16 or more carbon atoms (B) One or more anionic ones selected from the group consisting of N-stearoyl-N-methyltaurine sodium and N-stearoyl-L-glutamic acid and salts thereof. Surfactant (C) Contains liquid oil, the molar ratio (A / B) of the component (A) to the component (B) is 2.8 to 6, and the components (A) and (B) to the component (C). A liquid oil-in-water composition having a total mass ratio ((A + B) / C) of 0.3 to 0.75 and an average emulsified particle size of 160 nm or less.

The oil-in-water emulsified composition of the present invention is liquid but excellent in viscosity stability and emulsion stability over time, retains liquid properties without thickening for a long period of time, and is creamed and separated. It is possible to stably maintain a good emulsified state without causing such problems. Further, when the oil-soluble active ingredient is contained in the composition, the stability over time can be improved, and the action and effect based on the active ingredient can be stably maintained.

It is a figure which shows the result of the differential scanning calorimetry (DSC) about the composition of the average emulsified particle size 80 nm, 110 nm, 170 nm, 1 μm in Test Example 1. It is a figure which shows the result of X-ray diffraction about the composition of the average emulsification particle diameter 80nm, 110nm in Test Example 1. 3 is an electron micrograph of the composition having an average emulsified particle size of 110 nm in Test Example 1. It is an electron micrograph of the liposome in Reference Example 1.

Component (A) Examples of the linear saturated higher alcohol having 16 or more carbon atoms include cetyl alcohol, cetostearyl alcohol, stearyl alcohol, arachidyl alcohol, behenyl alcohol, lignoceryl alcohol, and ceryl alcohol, and one of them. Alternatively, two or more types can be used. Among these, from the viewpoint of viscosity stability and emulsion stability, setostearyl alcohol, stearyl alcohol, arachidyl alcohol, behenyl alcohol and the like are preferable, and setostearyl alcohol and stearyl alcohol are particularly preferable. The content of the component (A) in the oil-in-water composition of the present invention (hereinafter, may be simply referred to as “composition”) is 0.5 to 2% by mass (from the viewpoint of viscosity stability and emulsion stability). Hereinafter, it is preferably simply referred to as “%”), and more preferably 1 to 1.7%.

The component (B) is N-stearoyl-N-methyltaurine sodium, N-stearoyl-L-glutamic acid and a salt thereof, which are anionic surfactants, and the N-stearoyl-L-glutamic acid salt is a sodium salt. Examples thereof include potassium salts and magnesium salts, and one or more of these can be used. Among these, N-stearoyl-N-methyltaurine sodium, N-stearoyl-L-glutamic acid, and N-stearoyl-L-glutamic acid disodium are preferable from the viewpoint of viscosity stability and emulsion stability. The content of the component (B) in the composition of the present invention is preferably 0.4 to 1%, more preferably 0.5 to 0.9% from the viewpoint of viscosity stability and emulsion stability.

The liquid oil of component (C) can be used without particular limitation as long as it is liquid at room temperature (25 ° C.). For example, isododecane, isohexadecane, light isoparaffin, liquid paraffin (mineral oil), squalane, squalane, α-. Hydrocarbons such as olefin oligomer, polybutene, liquid isoparaffin, heavy liquid isoparaffin, polyisobutylene, hydrogenated polyisobutene; abrana seed oil, avocado oil, almond oil, apricot kernel oil, egoma oil, orange oil, olive oil, kiwi seed oil , Sesame oil, wheat germ oil, rice germ oil, rice bran oil, safflower oil, sage oil, soybean oil, tea seed oil, corn oil, rapeseed oil, evening primrose oil, camellia oil, persic oil, honeybee oil, peanut oil, sunflower Animal and vegetable oils such as oils, grape seed oils, meadowfoam oils, rosemary oils, jojoba oils, macadamia nut oils, lavender oils, rosehip oils, mink oils; Cetyl 2-ethylhexanoate, isopropyl myristate, isopropyl palmitate, -2-ethylhexyl palmitate, octyldodecyl myristate, glyceryl trioctanoate, glyceryl tri (capril capric acid), glyceryl diisostearate, glyceryl triisostearate, deca Decaglyceryl isostearate (polyglyceryl decisostearate-10), propylene glycol dicaprate, neopentyl glycol dicaprate, polyglyceryl triisostearate, diisostearyl malate, neopentyl glycol diethylhexanate, pentaerythrit tetraisostearate, tetra Esters such as pentaerythrit 2-ethylhexanoic acid, dipentaerythrit pentaisostearate, dialkyl carbonate, bisethoxydiglycol cyclohexane-1,4-dicarboxylate, hydrogenated rosin condensate of dimer dilinoleyl; oleic acid, Fatty acids such as isostearic acid; higher alcohols such as oleyl alcohol, 2-octyldodecanol, 2-decyltetradecanol, isostearyl alcohol, 2-hexyldecanol; dimethylpolysiloxane (dimethicone), methyltrimethicone, methylphenylpoly Siloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, tetramethyltetrahydrodi Encyclotetrasiloxane, Tetramethyltetraphenylcyclotetrasiloxane, Tetramethyltetratrifluoropropylcyclotetrasiloxane, Pentamethylpentatrifluoropropylcyclopentasiloxane, polyether-modified methylpolysiloxane, oleyl-modified methylpolysiloxane, polyvinylpyrrolidone-modified Silicone oils such as methylpolysiloxane; Fluorine oils such as perfluoropolyether, perfluorodecane, and perfluorooctane; lanolin derivatives such as lanolin acetate, lanolin fatty acid isopropyl, and lanolin alcohol; paramethoxysilicate skin acid 2- Examples thereof include liquid ultraviolet absorbers such as ethylhexyl and ethylhexyl salicylate, and one or more of these can be used.

Among these, non-polar oil is preferable from the viewpoint of viscosity stability and emulsion stability, and for example, isododecane, isohexadecane, light isoparaffin, liquid paraffin (mineral oil), squalane, squalane, α-olefin oligomer, polybutene, and liquid isoparaffin. , Heavy fluid isoparaffin, polyisobutylene, hydrogenated polyisobutene and other hydrocarbons, dimethylpolysiloxane (dimethicone), methyltrimethicone, methylphenylpolysiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, tetramethyltetrahydro Gencyclotetrasiloxane, tetramethyltetraphenylcyclotetrasiloxane, tetramethyltetratrifluoropropylcyclotetrasiloxane, pentamethylpentatrifluoropropylcyclopentasiloxane, polyether-modified methylpolysiloxane, oleyl-modified methylpolysiloxane, polyvinylpyrrolidone-modified methyl Examples thereof include silicone oils such as polysiloxane, and one or more of these can be used. In particular, liquid paraffin (mineral oil) and dimethylpolysiloxane (dimethicone) are preferably used. The content of the component (C) in the composition of the present invention is preferably 1 to 10%, more preferably 1.5 to 6.5% from the viewpoint of viscosity stability and emulsion stability. The mass ratio of polar oil to non-polar oil ((polar oil) / (non-polar oil)) is preferably 0.5 or less from the viewpoint of improving the oil-soluble active ingredient and the stability of viscosity and emulsification. , 0.3 or less is more preferable. The liquid oil of the component (C) does not include the oil-soluble active ingredient of the component (D) described later.

The polar oil used in the present invention preferably has an IOB (Inorganic-Organic balance) of 0.05 to 0.8, more preferably 0.05 to 0.6, from the viewpoint of viscosity stability and emulsion stability. Is even more preferable. The IOB of the non-polar oil used in the present invention is preferably less than 0.05, more preferably 0.03 or less, from the viewpoint of viscosity stability and emulsion stability.

Here, the IOB in the present invention is calculated by the following (Equation 1).
IOB = (Σ inorganic value / Σ organic) ... (Equation 1)
That is, the IOB is based on the "inorganic value" and "organic value" set for each of various atoms and functional groups, and the "inorganic value" of the atoms and functional groups constituting the organic compound such as a surfactant. , "Organic value" can be calculated by integrating (see Yoshio Koda, "Organic Conceptual Diagram-Basics and Applications-", pp. 11-17, Sankyo Publishing, 1984).

From the viewpoint of viscosity stability and emulsion stability, the mixed IOB of the liquid oil is preferably 0.8 or less, more preferably 0.6 or less, and further preferably 0.4 or less. It is more preferably 0.2 or less, and particularly preferably 0.2 or less.

Here, the mixed IOB (IOB _total ) of N kinds of liquid oils is calculated by the following (Equation 2).
IBO _total = IOB ₁・ W ₁ + IOB ₂・ W ₂ + ・ ・ ・ IOB _N・ W _N
... (Equation 2)
IOB ₁ , IOB ₂ , IOB _N : IOB of each liquid oil
W ₁ , W ₂ , W _N : Weight fraction of each liquid oil (W ₁ + W ₂ + ... + W _N = 1)

In the oil-in-water emulsification composition of the present invention, the molar ratio (A / B) of the component (A) to the component (B) is 2.8 to 6 from the viewpoint of viscosity stability and emulsion stability. Is preferable, and 2.8 to 4 is more preferable.

The total mass ratio of the components (A) and (B) to the component (C) ((A + B) / C)) is 0.3 to 0.75 from the viewpoint of viscosity stability and emulsion stability. It is preferably 0.3 to 0.72, and more preferably 0.3 to 0.72.

The water content in the composition of the present invention is preferably 70 to 85%, more preferably 75 to 80%, from the viewpoint of viscosity stability and emulsion stability.

An aqueous solvent can be used in addition to water for the composition of the present invention. Examples of the aqueous solvent include lower alcohols such as ethyl alcohol and propyl alcohol, glycols such as propylene glycol, 1,3-butylene glycol, dipropylene glycol, 1,2-pentanediol and polyethylene glycol, glycerin and diglycerin. , Glycerols such as polyglycerin, and the like, and one or more of these can be used. Among these, 1,3-butylene glycol, dipropylene glycol, glycerin, diglycerin, and polyglycerin are preferable from the viewpoint of viscosity stability and emulsion stability. When an aqueous solvent is used, the mass ratio of the aqueous solvent to water (water / aqueous solvent) is preferably 5 to 20, more preferably 6 to 15, from the viewpoint of viscosity stability and emulsion stability.

The composition of the present invention can further contain the component (D) oil-soluble active ingredient. Oil-soluble active ingredients include tocopherol, carotenoid, retinol, ceramide and glycyrrhetinic acid and esters thereof; oil-soluble licorice, oil-soluble yokuinin extract, oil-soluble rosemary extract, ubidecalenone and the like, and one or two of them. The above can be used. As the component (D), one or more selected from the group consisting of carotenoids and esters thereof is preferable. Carotenoids include actinioerythrol, astaxanthin, bixin, cantaxanthin, capsantin, capsorbin, β-8'-apo-carotene (apocarotenal), β-12'-apo-carotene, α-carotene, β-carotene, " Carotene "(mixture of α- and β-carotene), γ-carotene, δ-carotene, β-cryptoxanthin, ekinenone, palm oil carotene, rutin, lycopene, biorelitrin, zeaxanthin, fucoxanthin, anteraxanthin, violaxanthin, etc. Examples of the carotenoid ester include an ester in which a carotenoid containing a hydroxyl group or a carboxyl group and a fatty acid or a fatty alcohol form one or more ester bonds. In particular, as the component (D), one or more selected from the group consisting of astaxanthin and this ester is preferable. The fatty acid or fatty alcohol forming the ester is preferably one having a saturated or unsaturated hydrocarbon chain having a straight chain or a branched chain having 8 to 24 carbon atoms. The content of the component (D) in the composition of the present invention is appropriately set depending on the type of the oil-soluble active ingredient, and is preferably 0.00001 to 1%, more preferably 0.00001 to 0.5, for example.

In addition to the above components, any component can be used in the composition of the present invention as long as it does not impair the effects of the present invention. Examples of the optional component include solid oil, powder, ultraviolet scattering agent, preservative, fragrance and the like.

The composition of the present invention can be prepared by emulsifying and mixing the above-mentioned essential components and optional components to be blended as necessary according to a known method. For example, the oil phase containing the components (A) to (C) and the aqueous phase containing water are respectively heated and dissolved, the oil phase is added to the aqueous phase, emulsified and mixed using a dispersion or the like, and then micron. The oil-in-water composition of the present invention is prepared by high-pressure emulsification treatment using a fluidizer, an ultimateizer, a nanovaita or the like.

The average emulsified particle size of the oil-in-water composition of the present invention is 160 nm or less, preferably 60 to 130 nm, and more preferably 70 to 120 nm from the viewpoint of viscosity stability and emulsification stability. The average emulsified particle size can be adjusted by adjusting the pressure in the high-pressure emulsification treatment, the treatment time, the number of treatments, and the like. In the present specification, the average emulsified particle size is a value measured by the method described in Examples.

By setting the average emulsified particle size to 160 nm or less in this way, the oil-in-water composition of the present invention becomes excellent in viscosity stability over time while being liquid, and the reason is as follows. Conceivable. That is, in the process of producing the oil-in-water composition of the present invention, when α-gel is formed from the components (A) and (B), if the particle size of the emulsified droplet is large, a part of the α-gel is of the emulsified droplet. It exists in the surroundings and covers the emulsified droplets, but the other α-gels are dispersed in the continuous phase. It is considered that such excess α-gel forms a gel network over time and causes an increase in viscosity. On the other hand, as the particle size of the emulsified droplets is reduced, the proportion of α-gel existing around the emulsified droplets increases, and most α-gels cover the emulsified droplets in the range where the average emulsified particle size is 160 nm or less. As a result, the excess α-gel does not exist, so that the viscosity does not increase over time. When an anionic surfactant or a cationic surfactant other than the component (B) is used, the α-gel film structure that covers the emulsified droplets is not formed even if the average emulsified particle size is 160 nm or less. Therefore, the viscosity increases with time.

As described above, in the oil-in-water composition of the present invention, it is preferable that all or part of the emulsified droplets are coated with α-gel. The presence or absence of an α-gel film structure (hereinafter, sometimes referred to as “α-gel film structure”) that covers such emulsified droplets can be confirmed by differential scanning calorimetry (DSC) measurement. That is, when the emulsified droplets are large (for example, the average emulsified particle size is about 1 μm), one heat absorption peak based on the excess α-gel is observed in the range of 58 ° C. to 68 ° C. in the DSC measurement, but the particle size of the emulsified droplets. As the value becomes smaller, this heat absorption peak gradually shrinks, and another heat absorption peak based on the α-gel film structure that coats the emulsified droplet on the lower temperature side is observed. Thus, in the DSC measurement, two endothermic peaks based on the excess α-gel and α-gel membrane structure are observed in the range of 58 to 68 ° C., or only one endothermic peak based on the α-gel membrane structure on the lower temperature side is observed. If is observed, the presence of an α-gel membrane structure covering the emulsified droplets is recognized. The presence of the α-gel film structure covering the emulsified droplet can also be confirmed by observing a peak near 15 nm ^{-1 in} X-ray diffraction. That is, where the surface spacing of α-gel is about 4.15 Å, the wave number is because the equation q = 2 × π (pi) / d (plane spacing) holds between the surface spacing and the wave number q. It becomes 15 nm ^-1 (see Non-Patent Documents 1 and 2 and FIG. 2). Furthermore, the presence of the α-gel film structure covering the emulsified droplets can be confirmed by electron microscope observation (see FIG. 3).

The presence of such an α-gel film structure that covers the emulsified droplets is considered to contribute to the improvement of the stability of the oil-soluble active ingredient. That is, when the oil-in-water emulsified composition contains an oil-soluble active ingredient, the oil-soluble active ingredient is mainly present in the emulsified droplet, but does not always stay in the same place and is a molecule to the aqueous phase which is a continuous phase. Diffusion has occurred (Ostwald ripening, see Non-Patent Document 3), and the oil-soluble active ingredient comes into contact with continuous-phase water or the like, causing deterioration of the oil-soluble active ingredient. On the other hand, in the present invention, the presence of the α-gel film structure that covers the emulsified droplets makes the emulsified droplet interface stronger, so that the contact of the oil-soluble active ingredient with water or the like due to the Ostwald drying is suppressed, and as a result, the contact with water or the like is suppressed. It is presumed that the stability of the oil-soluble active ingredient over time is improved.

ここで、ｍ_iは試料量（ｇ）、ｃは記録データの送り速度（ｃｍ／ｓ）、ＰはＤＳＣ曲線の縦軸１ｃｍが１秒間で何ジュールに相当するかという値（Ｊ／ｃｍ・ｓ）である。 As described above, in the DSC measurement, the endothermic peak based on the excess α-gel on the higher temperature side (60 ° C or higher and 68 ° C or lower) and the lower temperature side (58 ° C or higher and lower than 60 ° C) are in the range of 58 ° C to 68 ° C. It may include one or both peaks of endothermic peaks based on the α-gel membrane structure that coats the emulsified droplets of. Q ₀ is the amount of heat (J / g) obtained from the total area of the endothermic peak included in the temperature range of 58 ° C to 68 ° C, Q ₁ is the amount of heat obtained from the area of the endothermic peak based on the excess α gel, and the emulsified droplets. the amount of heat obtained from the area of an endothermic peak based on the α gel film structure covering When Q _2, the ratio of the amount of heat obtained from the area of the endothermic peak based on the excess of α gel against heat obtained from the area of the whole endothermic peak Q ₁ From the viewpoint of viscosity stability, / Q ₀ is preferably 0.7 or less, more preferably 0.2 or less, and even more preferably 0.1 or less. The calories Q ₀ , Q ₁ , and Q ₂ obtained from the area of the endothermic peak are obtained as follows. That is, a DDSC curve which is a differential value of the obtained DSC curve is created, and the temperature at which the slope starts to occur in the DDSC curve is used as the base point. The peak area can be obtained by connecting the base points to the DSC curve (baseline). The area of the entire endothermic peak (cm ² ) included in the temperature range of 58 ° C to 68 ° C is A ₀ , the area of the endothermic peak based on the excess α gel (cm ² ) is A ₁ , and the α gel film covering the emulsified droplets. Assuming that the area of the endothermic peak (cm ² ) based on the structure is A ₂ , the calories Q ₀ , Q ₁ , and Q ₂ are expressed by the following equations.

Here, _mi is the sample amount (g), c is the feed rate of recorded data (cm / s), and P is the value of how many joules the vertical axis 1 cm of the DSC curve corresponds to in 1 second (J / cm ·. s).

The film thickness of the α-gel film in the α-gel film structure is preferably 5 to 20 nm, more preferably 5 to 10 nm, from the viewpoint of viscosity stability and emulsion stability. In the present specification, the film thickness of the α-gel film means the average value of the film thickness of the α-gel film of 100 emulsified droplets measured by electron microscope observation.

The oil-in-water emulsified composition of the present invention can be used as cosmetics, quasi-drugs, pharmaceuticals, etc., and its forms are makeups such as cosmetics, beauty essences, undiluted sprays, hair protectants, and liquid foundations. It is a liquid product such as a preparation. As used herein, the term "liquid" means that the viscosity measured by the method described in Examples is 100 mPa · s or less, preferably 50 to 0 mPa · s.

Next, examples and the like will be given to explain the present invention in more detail, but the present invention is not restricted by these examples and the like.

Test Example 1: Structural change and stability depending on the particle size of the emulsified droplet An oil-in-water composition having an average emulsified particle size of 80 nm, 110 nm, 170 nm and 1 μm was prepared by the following formulation and production method. DSC measurement was performed on each of the obtained compositions under the following conditions. Further, the compositions having an average emulsified particle size of 80 nm and 110 nm were subjected to X-ray diffraction by the following method. Further, the composition having an average emulsified particle size of 110 nm was observed with an electron microscope by the following method. The results are shown in FIGS.

(Prescription)
(Ingredient) (%)
1. 1. Dimethicone (25 ° C, 6 mPa · s) 5.0
2. 2. Cetyl alcohol 1.5
3. 3. Sodium N-stearoyl-N-methyltaurine 1.0
4.1,3-butylene glycol 12.0
5. Methylparaben 0.15
6. Phenoxyethanol 0.15
7. Purified water 80.2

(Manufacturing method)
A: No. 1 to 3 were uniformly heated, mixed and dissolved.
B: No. 4 to 7 were uniformly heated, mixed and dissolved.
C: A was added to B, emulsified and mixed, and then cooled.
High-pressure dispersion treatment (pressure 130 MPa) with a microfluidizer was performed twice for D-1: C to prepare an oil-in-water emulsified composition having an average emulsified particle size of 80 nm.
D-2: C was subjected to high-pressure dispersion treatment (pressure 100 MPa) three times with a microfluidizer to prepare an oil-in-water emulsified composition having an average emulsified particle size of 110 nm.
High-pressure dispersion treatment (pressure 80 MPa) with a microfluidizer was carried out twice for D-3: C to prepare an oil-in-water emulsified composition having an average emulsified particle size of 170 nm.
D-4: C was stirred with Desper at 2000 rpm to prepare an oil-in-water emulsified composition having an average emulsified particle size of 1 μm.

(Method of measuring average emulsified particle size)
Measurement principle Dynamic scattering method Solvent water Measurement temperature 20 ℃
Measuring device Real-time nanoparticle size measuring device DelsaMax CORE
Light Source 100 mW DPSS Single Longitudinal Mode Laser Laser Wavelength 658 nm
Detector particle size measurement avalanche photodiode (APD)
Detector angle Particle size measurement 90 °
Particle size calculation method Calculate the autocorrelation coefficient by the multi-tau method and calculate the particle size (DSC measurement method)
Equipment used; EXSTAR DSC6200 (manufactured by Seiko Instruments Inc.)
Reference; AIR
Rising temperature rate; 5 Cel / min,
Bread; P / N SSC000E031 AL15-CAPSULE
Analysis software; EXSTAR6000 Thermal analysis / rheology system (manufactured by Seiko Instruments Inc.)

(X-ray diffraction method)
Measuring equipment; SAXSess (manufactured by Anton Paar)
Measurement conditions; 25 ℃, 20min

As shown in FIG. 1, in the composition having an average emulsified particle size of 1 μm, an endothermic peak due to excess α-gel was observed around 61 ° C. This peak shrinks as the particle size of the emulsified droplet becomes smaller, but in the composition having an average emulsified particle size of 110 nm, in addition to this peak, a peak based on the α gel film structure covering the emulsified droplet is observed at around 58 ° C. It was. In the composition having an average emulsified particle size of 80 nm, the peak around 61 ° C. disappeared and only the peak around 58 ° C. was left. From this, at an average emulsified particle size of 1 μm to 170 nm, the α-gel is mainly dispersed as a surplus α-gel in the continuous phase, but at 110 nm, the α-gel covering the emulsified droplet and the surplus α-gel coexist. At 80 nm, it was suggested that the α-gel mainly exists as a coating for emulsified droplets. In the composition having an average emulsified particle size of 110 nm and 80 nm, the formation of an α-gel film structure covering the emulsified droplets means that a peak exists at 15 nm ^-1 in X-ray diffraction (Fig. 2) and an electron micrograph. This is also supported by (Fig. 3).

Based on FIG. 1, the amount of heat Q ₀ obtained from the total area of the endothermic peak, the amount of heat Q ₁ obtained from the area of the endothermic peak based on the surplus α gel, and the area of the endothermic peak based on the α gel film structure covering the emulsified droplets. the quantity of heat Q ₂ to which sought to calculate the analysis software determined using EXSTAR6000, ratio Q _{1 /} Q ₀ of the amount of heat obtained from the area of the endothermic peak based on the excess of α gel against heat obtained from the area of the whole endothermic peaks. The results are shown in Table 1.

For each composition, the viscosity and emulsified state immediately after production and after storage at 50 ° C. for 1 month were evaluated according to the following measuring methods and criteria. The results are shown in Table 2.

(Measurement / evaluation method of properties (viscosity))
Immediately after production and after storage at 50 ° C. for 1 month, the viscosity of each sample at 25 ° C. was measured and evaluated according to the following criteria. The viscosity was measured according to the cosmetic raw material standard / viscosity measurement method 2 using a Brookfield type viscometer.
(Judgment): (Measurement result)
⊚: 10 mPa · s or less 〇: More than 10 mPa · s and 100 mPa · s or less ×: More than 100 mPa · s

(Evaluation method of properties (emulsification state))
For each sample, the emulsified state immediately after production and after storage at 50 ° C. for 1 month was visually confirmed and evaluated according to the following criteria.
(Judgment): (Status)
〇: Creaming and separation are not observed Δ: Separation is not observed, but creaming is observed ×: Separation is observed

From Tables 1 and 2, the average emulsified particle size is 110 nm and the ratio Q ₁ / Q ₀ is 0, as compared with the test example in which the average emulsified particle size is 170 nm and the ratio Q ₁ / Q ₀ is 0.783. The test example having a viscosity of 136 and the test example having an average emulsified particle size of 80 nm and a ratio of Q ₁ / Q ₀ of 0 maintained a viscosity of 100 mPa · s or less without thickening even after storage at 50 ° C. for 1 month. It was confirmed that the viscosity stability over time was excellent.

Reference Example 1: Preparation of liposome-containing lotion The lotion having the composition shown below was prepared by the following production method. The obtained lotion was observed with an electron microscope. An electron micrograph is shown in FIG.

Reference example 1: Toner (ingredient) (%)
1. 1. Phospholipid 1.0
2. 2. Xanthan gum 0.1
3. 3. Carboxyvinyl polymer 0.05
4.1,3-butylene glycol 20.0
5. Glycerin 4.5
6. Sodium hydroxide 0.02
7. Paraoxybenzoic acid ester 0.1
8. Fragrance amount 9. Residual amount of purified water

(Production method)
A: No. Part of 1, 8 and 9 were liposomalized.
B: All the remaining components were mixed.
C: A and B were mixed to obtain a lotion.

The emulsified droplet having the α-gel membrane structure of the present invention in FIG. 3 has an oil phase inside, whereas the liposome in FIG. 4 does not have an oil phase inside, which is clearly different. Further, since the liposome forms a multi-lamellar membrane, it can be seen that the membrane structure exists in a plurality of layers, but the α-gel membrane structure of the present invention does not have a layered membrane structure, and the number of lamellar membranes is not observed. It turns out that there are few.
Further, it can be seen that the thickness of the α-gel film of the present invention is about 3 molecules of the linear saturated higher alcohol having 16 or more carbon atoms (the α-gel film is a higher alcohol trimolecular film). In order to adopt the α-gel film structure, it is possible to use a 5-layer film, a 7-layer film, a 9-layer film, etc., but in that case, a network structure is formed by increasing the number of films, and the thickness increases. there is a possibility. Therefore, the thickness of the α-gel film is preferably 5 to 20 nm, more preferably 5 to 10 nm from the viewpoint of viscosity stability and emulsion stability, and a linear saturated higher alcohol having 16 or more carbon atoms is approximately used. It is more preferable that the amount is 3 molecules (the α-gel film is a higher alcohol tri-molecule film).

Examples 1 to 14 and Comparative Examples 1 to 12
Toners having the compositions shown in Tables 3 to 6 below were prepared by the following production methods. The obtained lotion was evaluated for its viscosity and emulsified state immediately after production and after storage at 50 ° C. for 1 month according to the following measuring method and criteria. The existence of the α-gel membrane structure covering the emulsified droplet was evaluated by the following method. The results are also shown in Tables 3-6. The numerical values in the compositions of Tables 3 to 6 mean%.

*１　ニッコールＳＭＴ（日光ケミカルズ社製）
*２　アミソフトＨＡ－Ｐ（香栄興業社製）
*３　ニッコールＤＤＰ－８（日光ケミカルズ社製）

* 1 Nikkor SMT (manufactured by Nikko Chemicals)
* 2 Amisoft HA-P (manufactured by Koei Kogyo Co., Ltd.)
* 3 Nikkor DDP-8 (manufactured by Nikko Chemicals)

<Manufacturing method>
(Examples 1, 7, 8, 10)
A: No. 1 to 15 were uniformly heated, mixed and dissolved.
B: No. 16 to 19 were uniformly heated, mixed and dissolved.
C: A was added to B and emulsified and mixed.
D: C was cooled, and high-pressure dispersion treatment (pressure 200 MPa) was performed twice with a microfluidizer to obtain a lotion.

(Examples 2, 11-14)
A: No. 1 to 15 were uniformly heated, mixed and dissolved.
B: No. 16 to 19 were uniformly heated, mixed and dissolved.
C: A was added to B and emulsified and mixed.
D: C was cooled, and high-pressure dispersion treatment (pressure 200 MPa) was performed once with a microfluidizer to obtain a lotion.

(Examples 3 to 6, 9 and Comparative Examples 1 to 12)
A: No. 1 to 15 were uniformly heated, mixed and dissolved.
B: No. 16 to 19 were uniformly heated, mixed and dissolved.
C: A was added to B and emulsified and mixed.
D: C was cooled, and high-pressure dispersion treatment (pressure 100 MPa) was performed twice with a microfluidizer to obtain a lotion.

<Evaluation method>
(Existence of α-gel membrane structure covering emulsified droplets)
For each lotion, the endothermic peak was observed by DSC measurement under the following conditions, and the determination was made according to the following criteria.
[DSC conditions]
Equipment used; EXSTAR DSC6200 (manufactured by Seiko Instruments Inc.)
Reference; AIR
Rising temperature rate; 5 Cel / min,
Bread; P / N SSC000E031 AL15-CAPSULE
[Criteria]
(Judgment): (Status)
⊚: One peak was observed only around 58 ° C 〇: Two peaks were observed around 58 ℃ and 61 ℃ respectively Δ: One peak was observed only around 61 ℃ ×: Peak was observed Not observed-: Not measurable

With respect to the sample judged to be ⊚ or 〇 by the DSC measurement, it was observed that the α-gel film structure covered the emulsified droplets by electron microscopic observation (see FIG. 3; circled part in the figure). Further, X-ray diffraction (measuring instrument; SAXSess (manufactured by AntonPaar), measuring conditions; 25 ° C., 20 min) was performed, and a peak derived from the α gel film structure was observed at 15 nm ^-1 (see FIG. 2).

(Measurement / evaluation method of properties (viscosity))
Immediately after production and after storage at 50 ° C. for 1 month, the viscosity of each sample at 25 ° C. was measured and evaluated according to the following criteria. The viscosity was measured according to the cosmetic raw material standard / viscosity measurement method 2 using a Brookfield type viscometer.
(Judgment): (Measurement result)
⊚: 10 mPa · s or less 〇: More than 10 mPa · s and 100 mPa · s or less ×: More than 100 mPa · s

(Evaluation method of properties (emulsification state))
For each sample, the emulsified state immediately after production and after storage at 50 ° C. for 1 month was visually confirmed and evaluated according to the following criteria.
(Judgment): (Status)
〇: Creaming and separation are not observed Δ: Separation is not observed, but creaming is observed ×: Separation is observed

As shown in Tables 3 and 4, the lotions of Examples 1 to 14 all showed the presence of an α-gel film structure covering the emulsified droplets, became liquid immediately after production, and increased even after storage at 50 ° C. for 1 month. It maintained a viscosity of 100 mPa · s or less without sticking. In addition, no separation or creaming occurred, and a good emulsified state was maintained. On the other hand, in the lotions of Comparative Examples 1 and 2 having an average emulsified particle size of 170 nm or more, the existence of the α-gel film structure was not confirmed, and the viscosity increased with time. Further, the lotions of Comparative Examples 3 to 5 in which the component (A) a linear saturated higher alcohol having 16 or more carbon atoms was replaced with a branched one or one having less than 16 carbon atoms were separated immediately after production. Was observed (initial separation). Similarly, when a nonionic surfactant is used instead of the component (B), initial separation occurs (Comparative Example 6), and when a cationic surfactant or an anionic surfactant other than the component (B) is used. The existence of the α-gel film structure was not confirmed in the product, and even if the average emulsified particle size was 160 nm or less, the emulsion stability and viscosity stability were improved by separating after storage at 50 ° C. for 1 month and increasing the viscosity over time. It became inferior (Comparative Examples 11 and 12). Further, even when the content mass ratio of the component (C) to the total of the components (A) and (B) is outside the range of 0.3 to 0.75, the emulsion stability and the viscosity stability are similarly inferior. (Comparative examples 7 to 10).

Test Example 2: Stability test of oil-soluble active ingredient A lotion having the composition shown in Table 7 below was prepared by the following production method. The stability of the oil-soluble active ingredient of the obtained lotion was evaluated by the following method.

＊４　アスタキサンチン―５Ｃ（オリザ油化社製）
＊５　β－カロチン（三共製薬）
＊６　カネカ・コエンザイムＱ１０（カネカ）

* 4 Astaxanthin-5C (manufactured by Oriza Yuka Co., Ltd.)
* 5 β-carotene (Sankyo Pharmaceutical Co., Ltd.)
* 6 Kaneka Coenzyme Q10 (Kaneka)

(Production method)
A: No. 1 to 8 were uniformly heated, mixed and dissolved.
B: No. 9 to 12 were uniformly heated, mixed and dissolved.
C: A was added to B and emulsified and mixed.
D: C was cooled, and high-pressure dispersion treatment (pressure 130 MPa) was performed twice with a microfluidizer to obtain a lotion.

(Stability evaluation method for astaxanthin, β-carotene and ubidecalenone)
The absorbance of each lotion was measured immediately after production and after storage at 50 ° C. for 1 month. Using a spectrophotometer UV-2500PC UV-VIS REDCORDING SPECTROPHOTOMETER (manufactured by SHIMADZU), a glass cell with an optical path length of 10 mm and an optical path width of 10 mm, using purified water as a reference, and for astaxanthin, a wavelength of around 480 nm, β- Absorbance was measured at a wavelength of around 450 nm for carotene and at around 280 nm for ubidecalenone. The residual absorbance was calculated by the following formula, and the stability of astaxanthin, β-carotene, and ubidecalenone was evaluated according to the following criteria.
Residual absorbance (%) = (absorbance of sample after storage at 50 ° C for 1 month)
× 100 / (absorbance of sample immediately after production)

<Stability criteria>
(Judgment): (Residual absorbance)
⊚: Absorbance residual rate is 60% or more 〇: Absorbance residual rate is 50% or more and less than 60% ×: Absorbance residual rate is less than 50%

As shown in Table 7, in the lotion of Example 15, the fading of astaxanthin after storage at 50 ° C. for 1 month was clearly suppressed as compared with Comparative Example 13. This is because, in Example 15, the α-gel membrane structure covers the emulsified droplets and the emulsified droplet interface becomes stronger, so that the contact of astaxanthin with water or the like associated with the ostwald drying is suppressed, and as a result, the decomposition of astaxanthin is suppressed. However, in the cosmetic solution of Comparative Example 13, the α-gel film structure is not formed around the emulsified droplets, so that it is considered that contact of astaxanthin with water and the like and accompanying decomposition occur. Similarly, it was confirmed that β-carotene and ubidecalenone were stably maintained even after storage at 50 ° C. for 1 month.

Test Example 3: Ratio and stability of polar oil to non-polar oil A lotion having the composition shown in Table 8 below was prepared by the following production method. The obtained lotion was evaluated for its viscosity and emulsified state immediately after production and after storage at 50 ° C. for 1 month in the same manner as in Examples 1 to 14. The stability of astaxanthin was evaluated in the same manner as in Test Example 2. The results are also shown in Table 6.

＊７　ハイコールＫ－２３０（カネダ）
＊８　Ｍｙｒｉｔｏｌ　ＧＴＥＨ（ＢＡＳＦ）

* 7 HYCOAL K-230 (Kaneda)
* 8 Myritol GTEH (BASF)

(Production method)
A: No. 1 to 5 were uniformly heated, mixed and dissolved.
B: No. 6 to 9 were uniformly heated, mixed and dissolved.
C: A was added to B and emulsified and mixed.
D: C was cooled, and high-pressure dispersion treatment (pressure 130 MPa) was performed twice with a microfluidizer to obtain a lotion.

As shown in Table 8, the cosmetics of Examples 19 to 21 and 25 had better viscosity stability and emulsion stability after storage at 50 ° C. for 1 month than those of Example 27. .. Furthermore, the lotions of Examples 22 to 24 and 26 have higher viscosity stability, emulsion stability and oil-soluble active ingredient stability after storage at 50 ° C. for 1 month than those of Example 28. It was good. This is because the lower the mass ratio of polar oil to non-polar oil ((polar oil) / (non-polar oil)), the lower the compatibility with linear saturated higher alcohol, and the stability of the α-gel film structure over time at high temperature. This is thought to be due to the improved polarity.

Example 27: Toner (ingredient) (%)
1. 1. Dimethicone (25 ° C 6 mPa · s) 4.5
2. 2. Ethylhexyl palmitate ^{* 9} 0.5
3. 3. Setostearyl alcohol 1.5
4. Behenyl alcohol 0.8
5. Setostearyl alcohol 0.8
6. Sodium N-stearoyl-N-methyltaurine 0.7
7. Glycerin 1.0
8.1,3-butylene glycol 12.0
9. Tripropylene glycol 0.5
10. Citric acid 0.01
11. Na citrate 0.01
12. Remaining amount of purified water
* 9 Sarakos P-8 (manufactured by Nisshin Oillio Group)
(Production method)
A: No. 1 to 5 were uniformly heated, mixed and dissolved.
B: No. 6 to 12 were uniformly heated, mixed and dissolved.
C: A was added to B and emulsified and mixed.
D: C was cooled, and high-pressure dispersion treatment (pressure 130 MPa) was performed twice with a microfluidizer to obtain a lotion.

The lotion of Example 27 obtained as described above was a liquid of 30 mPa · s immediately after production, had an average emulsified particle size of 80 nm, and was in a good emulsified state. Viscosity stability and emulsification stability at 50 ° C. after 1 month were also good.

The oil-in-water emulsified composition of the present invention is liquid but has excellent viscosity stability and emulsification stability over time, and therefore can be used for liquid cosmetics, quasi-drugs, and the like.

Claims (6)

The following components (A) to (C);
(A) Linear saturated higher alcohol having 16 or more carbon atoms (B) N-stearoyl-N-methyltaurine sodium and N
It contains one or more anionic surfactants (C) liquid oil selected from the group consisting of -stearoyl-L-glutamic acid and salts thereof, and the content molar ratio (A /) of the component (A) to the component (B). B) is 2.8 to 6, the total mass ratio ((A + B) / C) of the components (A) and (B) to the component (C) is 0.3 to 0.75, and the average emulsified granules. A liquid oil-in-water composition having a diameter of 160 nm or less. The liquid oil-in-water composition according to claim 1, which has a viscosity at 25 ° C. of 100 mPa · s or less. The liquid oil-in-water composition according to claim 1 or 2, wherein the liquid oil component (C) is one or two selected from the group consisting of mineral oil and dimethicone. Component (C) The liquid water oil according to any one of claims 1 to 3, wherein the content mass ratio of the polar oil to the non-polar oil in the liquid oil ((polar oil) / (non-polar oil) is 0.5 or less). Mold composition. The liquid oil-in-water composition according to any one of claims 1 to 4, further containing the component (D) oil-soluble active ingredient. In the DSC curve measured by the differential scanning calorimeter, the ratio of the amount of heat obtained from the area of the endothermic peak based on the surplus α gel to the amount of heat obtained from the area of the entire endothermic peak included in the temperature range of 58 to 68 ° C is 0. The liquid oil-in-water composition according to any one of claims 1 to 5, which is 7. or less.

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