WO2023133795A1

WO2023133795A1 - Composition for conditioning keratin fibers

Info

Publication number: WO2023133795A1
Application number: PCT/CN2022/071981
Authority: WO
Inventors: Ya HU; Qingsheng Tao
Original assignee: LOreal SA
Current assignee: LOreal SA
Priority date: 2022-01-14
Filing date: 2022-01-14
Publication date: 2023-07-20
Anticipated expiration: 2024-07-14
Also published as: FR3131849A1; FR3131849B1; CN118541135A

Abstract

A transparent composition for conditioning keratin fibers, preferably hair, comprises a) a continuous oily phase, comprising at least one oil, and b) one or more polar phases, comprising deep eutectic solvents to carry an effective amount of hydrophilic active ingredients for conditioning keratin fibers, wherein the deep eutectic solvent includes a hydrogen bond donor and a hydrogen bond acceptor.

Description

COMPOSITION FOR CONDITIONING KERATIN FIBERS

TECHNIAL FIELD

The present invention relates to a composition for conditioning keratin fibers, in particular human keratin fibers, e.g., hair.

BACKGROUND ART

The hair is generally damaged and weakened by the action of external atmospheric agents such as light, weather, and/or the action of mechanical or chemical treatments such as brushing, combing, dyeing, bleaching, permanent and/or straightening.

There are many products comprising lipophilic active ingredients available for conditioning the hair. For example, there are many hair oil products comprising lipophilic active ingredients. In order to meet the needs of various consumers, cosmetic companies are keen to diversify the product categories of hair oil products. During the development of hair oil products, there is a challenge to include hydrophilic active ingredients for conditioning the hair, let alone high amount of the hydrophilic active ingredients. Thus, this relatively lower amount cannot satisfy the desirable benefits to keratin fibers.

Furthermore, it is highly desirable to provide the hair conditioning benefit using some products with pleasant appearance, for example, some products with transparent appearance, and it is also desirable that the products for conditioning the hair are stable over time.

Therefore, there is still a need to develop compositions for conditioning the keratin fibers, in particular human keratin fibers, e.g., hair, which comprises a relatively higher amount of hydrophilic active ingredients for conditioning the hair and improving sensorial performances, and which has a transparent appearance and is stable over time and thus providing long-term biological benefits to the keratin fibers.

SUMMARY OF THE INVENTION

In order to increase the hydrophilic active ingredients in the conditioning products of keratin fibers and simultaneously maintain the transparent appearance, we incorporate the deep eutectic solvents (DES) into the conditioning products, e.g. hair oils, for delivering said hydrophilic active ingredients, wherein the components constituting the deep eutectic solvents, per se, are active substances, and the deep eutectic solvent may further carry other active substances, e.g. hydrophilic plant extracts, hydrophilic dyes, hydrophilic preservatives, etc.

According to a first aspect, the present invention provides a transparent composition for conditioning keratin fibers, in particular hairs, comprising:

a) a continuous oily phase, comprising at least one oil; and

b) one or more polar phases, comprising deep eutectic solvents to carry an effective amount of hydrophilic active ingredients for conditioning keratin fibers. As mentioned above, the expression "deep eutectic solvents to carry an effective amount of hydrophilic active ingredients for conditioning keratin fibers" means that the deep eutectic solvents, per se, are active substances, and may further carry other active substances, e.g. hydrophilic plant extracts, hydrophilic dyes, hydrophilic preservatives, etc.

Preferably, the polar phases comprise less than about 10 wt. %of water, and particularly less than about 6 wt. %of water, relative to the weight of the deep eutectic solvents. More preferably, the polar phases substantially do not comprise water, and it means that the polar phases comprise a trace amount of water, i.e. the water is comprised as an impurity, if present.

The transparent composition comprising the effective amount of the hydrophilic active ingredient offers consumers with actives for nourishing keratin fibers and improved sensorial experiences.

For the deep eutectic solvent according to the present invention, it includes a hydrogen bond donor and a hydrogen bond acceptor, and both of them are physiologically beneficial actives, and are the above hydrophilic active ingredients per se.

According to the present invention, the transparent composition may or may not comprise a surfactant. In one aspect, the transparent composition does not comprise any surfactant. In another aspect, , the transparent composition comprises a surfactant combination comprising at least one nonionic surfactant, and optionally at least one ionic surfactant, wherein the ionic surfactant is preferably chosen from anionic surfactants.

By means of the surfactant combination, reverse micelles are formed in the composition, such that the composition has a transparent appearance and is thermodynamically stable over time. In the reverse micelle system, the DES, instead of water, serves as the cores inside. Moreover, by means of the surfactant combination, a relatively higher amount of hydrophilic active ingredients are comprised. Further, since DES, per se, are hydrophilic active ingredients, the composition of the present invention often carries higher amount of actives than the compositions comprising the reverse micelle system containing water cores.

For the surfactant combination, in order to meet the safety standard and not damage the health of users, the surfactant combination is present in a relatively lower amount, and comprises at least one nonionic surfactant and optionally at least one ionic surfactant. In one embodiment, the amount of the at least one ionic surfactant is not higher than about 1.0 wt. %, relative to the total weight of the composition. Surprisingly, the inventor discovers that the reverse micelles can be formed and maintained in the composition of the present invention even at a very low amount of ionic surfactant.

Theoretically, any oils that are suitable for the treatment of the keratin fibers are applicable to the composition of the present invention. In one embodiment, the at least one oil is selected from hydrocarbon oils, silicone oils, triglycerides, ether oils, and mixtures thereof.

According to a second aspect, the present invention provides hair oils, including leave-on hair oils and rinse-off hair oils, comprising, substantially consisting of or consisting of the above transparent composition, in the form of bi-phasic oils or homogeneous oils. For the homogeneous oils, the above reverse micelles comprising the specific surfactant combination are formed.

Other subjects and characteristics, aspects and advantages of the present invention will emerge even more clearly on reading the detailed description and the examples that follow.

BRIEF DESCRIPTION OF FIGURES

Fig. 1 is the multimodal size distribution of Sample 1, corresponding to Inventive Example 2, from Brookhaven dynamic light scattering (DLS) equipment.

Fig. 2 is the multimodal size distribution of Sample 2, corresponding to Inventive Example 3, from Brookhaven dynamic light scattering (DLS) equipment.

Each measurement of the Brookhaven DLS analyser determines the average diameter (effective diameter) and the distribution width (polydispersity) of the samples, wherein DLS measures the correlation function of intensity fluctuations, which can be mathematically converted into an intensity size distribution, and the diagram describes the multimodal intensity size distribution of the sample where a numerical algorithm is used.

DETAILD DESCRIPTION OF THE INVENTION

As used herein, unless otherwise indicated, the limits of a range of values are included within this range, in particular in the expressions "between... and... " and "from... to ... ” .

As used herein, the term "comprising" is to be interpreted as encompassing all specifically mentioned features as well optional, additional, unspecified ones.

As used herein, the use of the term “comprising” also discloses the embodiment wherein no features other than the specifically mentioned features are present (i.e. "consisting of" ) .

The articles "a" and "an, " as used herein, mean one or more when applied to any feature in embodiments of the present invention described in the specification and claims. The use of "a" and "an" does not limit the meaning to a single feature unless such a limit is specifically stated.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the field the present invention belongs to. When the definition of a term in the present description conflicts with the meaning as commonly understood by those skilled in the field the present invention belongs to, the definition described herein shall apply.

Unless otherwise specified, all numerical values expressing amount of ingredients and the like used in the description and claims are to be understood as being modified by the term "about" . Accordingly, unless indicated to the contrary, the numerical values and parameters described herein are approximate values which are capable of being changed according to the desired performance obtained as required.

As used therein, the term "keratin fibers" includes animal keratin fibers and human keratin fibers such as the hair.

As used herein, the expression "at least one" used in the present description is equivalent to the expression "one or more" .

As used therein, the term "deep eutectic solvent" means that it is present as a liquid state at room temperature. Comparing with ionic liquids, the preparation of deep eutectic solvents is simpler, faster, cheaper, and less toxic, and is called a "green solvent" . Deep eutectic solvent is mainly composed of a hydrogen bond donor and a hydrogen bond acceptor to form a binary and ternary system of deep eutectic solvents. The most significant physical property of the deep eutectic solvent is the decrease in the melting point of the solvent. As a new type of green solvent that can replace ionic liquids, it has a wide range of uses and can be used for separation of natural organic components, or used as reaction solvents, etc.

As used therein, the term "reverse micelles" or "reversed micelles" has the following definition: surfactants are dissolved in non-polar organic solvents; when their concentration exceeds the critical micelle concentration (CMC) , the micelles formed in the organic solvent, which are called reverse micelles, or reversed micelles. In reverse micelles, the non-polar groups of the surfactant are externally in contact with non-polar organic solvents, while the polar groups are arranged inside to form a polar core. This polar core has the ability to dissolve polar substances. In the case that the polar core contains water, it forms a "water pool" or "water core" . Reverse micelle is a nano-scale aggregate, which is a transparent and thermodynamically stable W/O system.

As used therein, the term "lipophilic" means a substance or material can be dissolved or dispersed in an oily phase at 25 ℃ in order to obtain a macroscopically homogeneous phase.

As used therein, the term "effective amount" means an amount of the hydrophilic active ingredient comprised in the polar phases of the composition, said amount being sufficient to effectively condition the keratin fibers. According to the present invention, the effective amount can be about 0.01 wt. %or even higher, e.g. about 0.05 wt. %, about 0.1 wt. %, about 0.15 wt. %, about 0.2 wt. %, about 0.25 wt. %, about 0.30 wt. %, about 0.35 wt.%, about 0.40 wt. %, about 0.45 wt. %, about 0.5 wt. %, about 0.6 wt. %, about 0.7 wt. %, about 0.8 wt. %, about 1.0 wt. %, about 1.5 wt. %, about 2.0 wt. %, about 2.5 wt. %, about 3.0 wt. %, about 4.0 wt. %, about 5.0 wt. %, relative to the total weight of the composition.

Oily phase

According to the first aspect of the present invention, a transparent composition is provided, and the composition comprises a continuous oily phase comprising at least one oil.

Here, "oil" means a fatty compound or substance which is in the form of a liquid or a paste (non-solid) at room temperature (25℃) under atmospheric pressure (760 mmHg) .

As the oil (s) , those generally used in cosmetics can be used alone or in combination thereof. These oil (s) may be volatile or non-volatile, preferably non-volatile.

The oil may be a non-polar oil such as hydrocarbons, silicones, or the like; a polar oil such as esters, fatty alcohols and ethers; or a mixture thereof.

The oil may be oils of plant or animal origin and synthetic oils.

As examples of plant oils, mention may be made of, for example, linseed oil, camellia oil, macadamia nut oil, corn oil, mink oil, olive oil, avocado oil, sasanqua oil, castor oil, safflower oil, jojoba oil, sunflower oil, almond oil, rapeseed oil, sesame oil, soybean oil, peanut oil, and mixtures thereof.

As examples of synthetic oils, mention may be made of alkane oils such as isododecane and isohexadecane, ester oils, ether oils, and artificial triglycerides.

The ester oils are preferably liquid esters of saturated or unsaturated, linear or branched C ₁-C ₂₆ aliphatic monoacids or polyacids and of saturated or unsaturated, linear or branched C ₁-C ₂₆ aliphatic monoalcohols or polyalcohols, the total number of carbon atoms of the esters being greater than or equal to 10.

Preferably, for the esters of monoalcohols, at least one from among the alcohol and the acid, from which the esters of the present invention are derived, is branched.

Among the monoesters of monoacids and of monoalcohols, mention may be made of ethyl palmitate, ethyl hexyl palmitate, isopropyl palmitate, dicaprylyl carbonate, alkyl myristates such as isopropyl myristate or ethyl myristate, isocetyl stearate, 2-ethylhexyl isononanoate, isononyl isononanoate, isodecyl neopentanoate and isostearyl neopentanoate.

Esters of C ₄-C ₂₂ dicarboxylic or tricarboxylic acids and ofC ₁-C ₂₂ alcohols, and esters of monocarboxylic, dicarboxylic or tricarboxylic acids and of non-sugar C ₄-C ₂₆ dihydroxy, trihydroxy, tetrahydroxy or pentahydroxy alcohols may also be used.

Mention may especially be made of: diethyl sebacate; isopropyl lauroyl sarcosinate; diisopropyl sebacate; bis (2-ethylhexyl) sebacate; diisopropyl adipate; di-n-propyl adipate; dioctyl adipate; bis (2-ethylhexyl) adipate; diisostearyl adipate; bis (2-ethylhexyl) maleate; triisopropyl citrate; triisocetyl citrate; triisostearyl citrate; glyceryl trilactate; glyceryl trioctanoate; trioctyldodecyl citrate; trioleyl citrate; neopentyl glycol diheptanoate; diethylene glycol diisononanoate.

As ester oils, one can use sugar esters and diesters of C ₆-C ₃₀ and preferably C ₁₂-C ₂₂ fatty acids. It is recalled that the term “sugar” means oxygen-bearing hydrocarbon-based compounds containing several alcohol functions, with or without aldehyde or ketone functions, and which comprise at least 4 carbon atoms. These sugars may be monosaccharides, oligosaccharides or polysaccharides.

Examples of suitable sugars that may be mentioned include sucrose (or saccharose) , glucose, galactose, ribose, fucose, maltose, fructose, mannose, arabinose, xylose and lactose, and derivatives thereof, especially alkyl derivatives, such as methyl derivatives, for instance methylglucose.

The sugar esters of fatty acids may be selected especially from the group comprising the esters or mixtures of esters of sugars described previously and of linear or branched, saturated or unsaturated C ₆-C ₃₀ and preferably C ₁₂-C ₂₂ fatty acids. If they are unsaturated, these compounds may have one to three conjugated or non-conjugated carbon-carbon double bonds.

The esters according to this variant may also be selected from monoesters, diesters, triesters, tetraesters and polyesters, and mixtures thereof.

These esters may be, for example, oleates, laurates, palmitates, myristates, behenates, cocoates, stearates, linoleates, linolenates, caprates and arachidonates, or mixtures thereof such as, especially, oleopalmitate, oleostearate and palmitostearate mixed esters, as well as pentaerythrityl tetraethyl hexanoate.

More particularly, use is made of monoesters and diesters and especially sucrose, glucose or methylglucose monooleates or dioleates, stearates, behenates, oleopalmitates, linoleates, linolenates and oleostearates.

An example that may be mentioned is the product sold under the name Glucate`DO by the company Amerchol, which is a methylglucose dioleate.

As examples of preferable ester oils, mention may be made of, for example, diisopropyl adipate, dioctyl adipate, 2-ethylhexyl hexanoate, ethyl laurate, cetyl octanoate, octyldodecyl octanoate, isodecyl neopentanoate, myristyl propionate, 2-ethylhexyl 2-ethylhexanoate, 2-ethylhexyl octanoate, 2-ethylhexyl caprylate/caprate, methyl palmitate, ethyl palmitate, isopropyl palmitate, dicaprylyl carbonate, isopropyl lauroyl sarcosinate, isononyl isononanoate, ethylhexyl palmitate, isohexyl laurate, hexyl laurate, isocetyl stearate, isopropyl isostearate, isopropyl myristate, isodecyl oleate, glyceryl tri (2-ethylhexanoate) , pentaerythrithyl tetra (2-ethylhexanoate) , 2-ethylhexyl succinate, diethyl sebacate, and mixtures thereof.

As examples of artificial triglycerides, mention may be made of, for example, caprylic/capric triglyceride, glyceryl trimyristate, glyceryl tripalmitate, glyceryl trilinolenate, glyceryl trilaurate, glyceryl tricaprate, glyceryl tricaprylate, and glyceryl tri (caprate/caprylate/linolenate) .

The ether hydrocarbon-based oil, also known as an ether oil, may be volatile or non-volatile and is preferably non-volatile.

An ether hydrocarbon-based oil is an oil of formula R ₁OR ₂ in which R ₁ and R ₂ independently denote a linear, branched or cyclic C ₄-C ₂₄ alkyl group, preferably a C ₆-C ₁₈ alkyl group, and preferably a C ₈-C ₁₂ alkyl group. It may be preferable for R ₁ and R ₂ to be identical.

Linear alkyl groups that may be mentioned include a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, an eicosyl group, a behenyl group, a docosyl group, a tricosyl group and a tetracosyl group.

Branched alkyl groups that may be mentioned include a 1-methylpropyl group, a 2-methylpropyl group, a t-butyl group, a 1, 1-dimethylpropyl group, a 3-methylhexyl group, a 5-methylhexyl group, an ethylhexyl group, a 2-ethylhexyl group, a 5-methyloctyl group, a 1 -ethylhexyl group, a 1-butylpentyl group, a 2-butyloctyl group, an isotridecyl group, a 2-pentylnonyl group, a 2-hexyldecyl group, an isostearyl group, a 2-heptylundecyl group, a 2-octyldodecyl group, a 1, 3-dimethylbutyl group, a 1- (1-methylethyl) -2-methylpropyl group, a 1, 1, 3, 3-tetramethylbutyl group, a 3, 5, 5-trimethylhexyl group, a 1- (2-methylpropyl) -3-methylbutyl group, a 3, 7-dimethyloctyl group and a 2- (1, 3, 3-trimethylbutyl) -5, 7, 7-trimethyloctyl group.

Cyclic alkyl groups that may be mentioned include a cyclohexyl group, a 3-methylcyclohexyl group and a 3, 3, 5-trimethylcyclohexyl group.

Advantageously, the ether oil is chosen from dicaprylyl ether, dicapryl ether, dilauryl ether, diisostearyl ether, dioctyl ether, nonyl phenyl ether, dodecyl dimethylbutyl ether, cetyl dimethylbutyl ether, cetyl isobutyl ether, and mixtures thereof.

Preferably, it is chosen from dicaprylyl ether, dicapryl ether, dilauryl ether, diisostearyl ether, dioctyl ether, and mixtures thereof. Dicaprylyl ether is most particularly suitable for use.

As examples of silicone oils, mention may be made of, for example, linear organopolysiloxanes such as dimethylpolysiloxane, methylphenylpolysiloxane, methylhydrogenpolysiloxane, and the like; cyclic organopolysiloxanes such as cyclohexasiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, and the like; and mixtures thereof.

Preferably, silicone oil is selected from liquid polydialkylsiloxanes, especially liquid polydimethylsiloxanes (PDMS) and liquid polyorganosiloxanes comprising at least one aryl group.

These silicone oils may also be organomodified. The organomodified silicones that can be used in accordance with the present invention are silicone oils as defined above and comprise in their structure one or more organofunctional groups attached via a hydrocarbon-based group.

Organopolysiloxanes are defined in greater detail in Walter Noll’s Chemistry and Technology of Silicones (1968) , Academic Press. They may be volatile or non-volatile.

When they are volatile, the silicones are more particularly selected from those having a boiling point of between 60℃ and 260℃, and even more particularly from:

(i) cyclic polydialkylsiloxanes comprising from 3 to 7 and preferably 4 to 5 silicon atoms. These are, for example, octamethylcyclotetrasiloxane sold in particular under the name Volatile

7207 by Union Carbide or

70045 V2 by Rhodia, decamethylcyclopentasiloxane sold under the name Volatile

7158 by Union Carbide,

70045 V5 by Rhodia, and dodecamethylcyclopentasiloxane sold under the name Silsoft 1217 by Momentive Performance Materials, and mixtures thereof. Mention may also be made of cyclocopolymers of the type such as dimethylsiloxane/methylalkylsiloxane, such as Silicone

FZ 3109 sold by the company Union Carbide, of formula:

Mention may also be made of mixtures of cyclic polydialkylsiloxanes with organosilicon compounds, such as the mixture of octamethylcyclotetrasiloxane and tetratrimethylsilylpentaerythritol (50/50) and the mixture of octamethylcyclotetrasiloxane and oxy-1, 1’-bis (2, 2, 2’, 2’, 3, 3’-hexatrimethylsilyloxy) neopentane;

(ii) linear volatile polydialkylsiloxanes containing 2 to 9 silicon atoms and having a viscosity of less than or equal to 5×10 ^-6 m ²/s at 25℃. An example is decamethyltetrasiloxane sold in particular under the name SH 200 by the company Toray Silicone. Silicones belonging to this category are also described in the article published in Cosmetics and Toiletries, Vol. 91, Jan. 76, pp. 27-32, Todd &Byers, Volatile Silicone Fluids for Cosmetics. The viscosity of the silicones is measured at 25℃ according to ASTM standard 445 Appendix C.

Non-volatile polydialkylsiloxanes may also be used. These non-volatile silicones are more particularly selected from polydialkylsiloxanes, among which mention may be made mainly of polydimethylsiloxanes containing trimethylsilyl end groups.

Among these polydialkylsiloxanes, mention may be made, in a non-limiting manner, of the following commercial products:

-the

oils of the 47 and 70 047 series or the

oils sold by Rhodia, for instance the oil 70 047 V 500 000;

-the oils of the

series sold by the company Rhodia;

-the oils of the 200 series from the company Dow Corning, such as DC200 with a viscosity of 60 000 mm ²/s;

-the

oils from General Electric and certain oils of the SF series (SF 96, SF 18) from General Electric.

Mention may also be made of polydimethylsiloxanes containing dimethylsilanol end groups known under the name dimethiconol (CTFA) , such as the oils of the 48 series from the company Rhodia.

Among the silicones containing aryl groups are polydiarylsiloxanes, especially polydiphenylsiloxanes and polyalkylarylsiloxanes. Examples that may be mentioned include the products sold under the following names:

-the

oils of the 70 641 series from Rhodia;

-the oils of the

70 633 and 763 series from Rhodia;

-the oil Dow Corning 556 Cosmetic Grade Fluid from Dow Corning;

-the silicones of the PK series from Bayer, such as the product PK20;

-certain oils of the SF series from General Electric, such as SF 1023, SF 1154, SF 1250 and SF 1265.

The organomodified liquid silicones may especially contain polyethyleneoxy and/or polypropyleneoxy groups. Mention may thus be made of the silicone KF-6017 proposed by Shin-Etsu, and the oils

L722 and L77 from the company Union Carbide.

Hydrocarbon oils may be selected from:

-linear or branched, optionally cyclic, C ₆-C ₁₆ lower alkanes. Examples that may be mentioned include hexane, undecane, dodecane, tridecane, and isoparaffins, for instance isohexadecane, isododecane and isodecane; and

-linear or branched hydrocarbons containing more than 16 carbon atoms, such as liquid paraffins, liquid petroleum jelly, polydecenes and hydrogenated polyisobutenes such as

and squalane.

As preferable examples of hydrocarbon oils, mention may be made of, for example, linear or branched hydrocarbons such as isohexadecane, isododecane, squalane, mineral oil(e.g., liquid paraffin) , paraffin, vaseline or petrolatum, naphthalenes, and the like; hydrogenated polyisobutene, isoeicosan, and decene/butene copolymer; and mixtures thereof.

As examples, the oil is selected from branched alkane oils containing from 8 to 20 carbon atoms and better still from 10 to 16 carbon atoms such as isododecane, triglycerides such as caprylic/capric triglyceride, an ether hydrocarbon-based oil having a C ₈-C ₁₂ alkyl group such as dicaprylyl ether, polydimethylsiloxanes optionally containing dimethylsilanol end groups such as dimethicones, dimethiconols, and mixtures thereof.

Preferably, the oil is selected from isododecane, caprylic/capric triglyceride, dicaprylyl ether, dimethicones, dimethiconols, and mixtures thereof.

Advantageously, the oil is present in an amount ranging from about 10 wt. %to about 99 wt. %, preferably from about 25 wt. %to about 97 wt. %, or from about 50 wt. %to about 95 wt. %, relative to the total weight of the composition.

Polar phase

The composition of the present invention comprises one or more polar phases of deep eutectic solvents to carry an effective amount of hydrophilic active ingredients for conditioning keratin fibers.

Preferably, the polar phases comprise less than about 10 wt. %of water, and particularly less than about 6 wt. %of water, relative to the weight of the deep eutectic solvents. More preferably, the polar phases substantially do not comprise water, or even the water is comprised as an impurity, if present. The term "substantially do not comprise water" means that the polar phases comprise 5 wt. %or less of water, relative to the weight of the deep eutectic solvents.

Further, the polar phases of the composition according to the present invention may comprise one or more water-miscible or at least partially water-miscible compounds, for instance C ₂-C ₈ lower polyols, or monoalcohols, such as ethanol and isopropanol.

The term “polyol” should be understood as meaning any organic molecule comprising at least two free hydroxyl groups. Examples of polyols that may be mentioned include glycols, for instance butylene glycol, propylene glycol, pentylene glycol, isoprene glycol, caprylyl glycol, glycerol (i.e.glycerin) and polyethylene glycols.

The water-miscible or at least partially water-miscible compounds, if present, may represent from about 0.1 wt. %to about 40 wt. %, preferably from about 1 wt. %to about 30 wt. %, or from about 5 wt. %to about 25 wt. %, relative to the total weight of the composition.

Deep eutectic solvent (DES)

The deep eutectic solvent according to the present invention includes a hydrogen bond donor (HBD) and a hydrogen bond acceptor (HBA) , wherein both of the hydrogen bond donor and the hydrogen bond acceptor are physiologically beneficial actives, and are per se the hydrophilic active ingredients comprised in the composition of the present invention.

In particular, the expression "hydrophilic” is exchangeable with the term "water-soluble" , and the term "hydrophilic" is intended to characterize the capacity of a compound to dissolve in water, measured at 25℃, to a concentration at least equal to 0.1 g/l (production of a macroscopically isotropic, transparent, coloured or colourless solution) . This solubility is in particular greater than or equal to 1 g/l.

Specifically, the hydrogen bond donors comprised in the composition of the present invention are acids, alcohols, amines or carbohydrates, and are preferably organic acids, and are especially selected from lactic acid, glycolic acid, salicylic acid, nicotinic acid, oxalic acid, citric acid, tartaric acid, malic acid, adipic acid, galacturonic acid, and gluconic acid. Preferably, the hydrogen bond donors are selected from lactic acid, glycolic acid, salicylic acid and citric acid. In particular, the hydrogen bond donors are chosen from lactic acid.

The hydrogen bond acceptors are chosen from quaternary salts, including quaternary ammonium salts and quaternary phosphonium salts, e.g. betaine and choline chloride; polyols derived from sugars, e.g. trehalose, xylitol, glucose, and panthenol; and some amino acids, e.g. alanine, glycine, histidine, and proline. Preferably, the hydrogen bond acceptors are selected from betaine, trehalose, glucose, and panthenol. In particular, the hydrogen bond acceptors are chosen from betaine.

Advantageously, the weight ratio of the hydrogen bond acceptors to the hydrogen bond donors ranges from about 1∶20 to about 1∶0.1, preferably from about 1∶13 to about 1∶0.5, or from about 1∶10 to about 1∶0.8, e.g. about 1∶7, about 1∶5, about 1∶3, about 1∶2, about 1∶1.5, about 1∶1.2, about 1∶1, and about 1∶0.9.

Advantageously, the deep eutectic solvent including the a hydrogen bond acceptor and a hydrogen bond donor is present in an amount ranging from about 0.01 wt. %to about 50 wt. %, preferably from about 0.05 wt. %to about 35 wt. %, or from about 0.1 wt. %to about 25 wt. %, relative to the total weight of the composition.

Other hydrophilic active ingredients

According to the present invention, the polar phases may carry an amount of other hydrophilic active ingredients for conditioning keratin fibers, than the above deep eutectic solvents, meaning any natural or synthetic, generally organic compound which is soluble in the deep eutectic solvent. For example, the other hydrophilic active ingredients may include plant extracts, dyes and preservatives.

As hydrophilic plant extracts, mention can be made of citrus jundos fruit extract, aloe vera extract, lavender extract, citrus aurantium extract, ginkgo biloba extract, lemon extract and zingiber officinale extract and the like.

As hydrophilic dyes, mention may be made in particular of synthetic or natural water-soluble dyes, including acidic or basic water-soluble dyes, for instance FD&C Red 4 (CI: 14700) , DC Red 6 (Lithol Rubine Na; CI: 15850) , DC Red 22 (CI: 45380) , DC Red 28 (CI: 45410 Na salt) , DC Red 30 (CI: 73360) , DC Red 33 (CI: 17200) , ACID Red 52 (CI: 45100) , DC Orange 4 (CI: 15510) , FDC Yellow 5 (CI: 19140) , FDC Yellow 6 (CI: 15985) , DC Yellow 8 (CI: 45350 Na salt) , FDC Green 3 (CI: 42053) , DC Green 5 (CI: 61570) , FDC Blue 1 (CI: 42090) , Acid Black 1, Basic Orange 31, Basic Red 51, Basic Yellow 87, Basic Red 76, and combinations thereof.

As hydrophilic preservatives, mention may be made in particular of pentylene glycol, phenoxyethanol, salicylic acid, capryl glycol, sodium benzonate, and the like.

Surfactant combination

The composition of the present invention optionally comprises a surfactant combination, consisting of at least one nonionic surfactant and optionally at least one ionic surfactant, wherein the ionic surfactant is preferably chosen from anionic surfactants.

So far, there is almost no oily system or phase using the reverse micelle technology to obtain dispersed polar phases comprising deep eutectic solvents, to carry an effective amount of a hydrophilic active ingredient for conditioning keratin fibers.

By means of the surfactant combination, reverse micelles are formed in the composition, such that the composition has a transparent appearance and is thermodynamically stable over time. Moreover, by means of the surfactant combination, a relatively higher amount of hydrophilic active ingredients are comprised. Further, since DES, per se, are hydrophilic active ingredients, the composition of the present invention often carries higher amount of actives than the compositions comprising reverse micelle system containing water cores.

Advantageously, the surfactant combination is present in an amount ranging from about 0.1 wt. %to about 20 wt. %, preferably from about 0.5 wt. %to about 10 wt. %, or from about 1 wt. %to about 5 wt. %, relative to the total weight of the composition.

Nonionic surfactant

The nonionic surfactant according to the present invention is preferably lipophilic.

As nonionic surfactants, mention can be made of the nonionic surfactant having at least one C ₆-C ₂₂ alkyl chain, e.g. one, two or three C ₆-C ₂₂ alkyl chains, and preferably the nonionic surfactant further has an HLB value ranging from about 0 to about 10.

As examples, mention can be made of esters of polyols with fatty acids with a saturated or unsaturated chain containing for example from 6 to 22 carbon atoms, preferably 12 to 22 carbon atoms, and alkoxylated derivatives thereof, preferably with a number of alkyleneoxide of from 10 to 200, and more preferably from 10 to 100, such as glyceryl esters of a C ₆-C ₂₂, preferably C ₁₂-C ₂₂, fatty acid or acids and alkoxylated derivatives thereof, preferably with a number of alkyleneoxide of from 10 to 200, and more preferably from 10 to 100; polyethylene glycol esters of a C ₆-C ₂₂, preferably C ₁₂-C ₂₂, fatty acid or acids and alkoxylated derivatives thereof, preferably with a number of alkyleneoxide of from 10 to 200, and more preferably from 10 to 100; sorbitol esters of a C ₆-C ₂₂, preferably C ₁₂-C ₂₂, fatty acid or acids and alkoxylated derivatives thereof, preferably with a number of alkyleneoxide of from 10 to 200, and more preferably from 10 to 100; sugar (sucrose, glucose, alkylglycose) esters of a C ₆-C ₂₂, preferably C ₁₂-C ₂₂, fatty acid or acids and alkoxylated derivatives thereof, preferably with a number of alkyleneoxide of from 10 to 200, and more preferably from 10 to 100; and a mixture thereof.

Examples of ethoxylated fatty esters that may be mentioned include the adducts of ethylene oxide with esters of lauric acid, palmitic acid, stearic acid or behenic acid, and a mixture thereof, especially those containing from 9 to 100 oxyethylene groups, such as ethylene glycol dilaurate, ethylene glycol distearate, PEG-3 distearate, PEG-8 distearate, PEG-12 distearate, PEG-100 distearate, PEG-150 distearate, PEG-2 dilaurate, PEG-4 dilaurate, PEG-8 dilaurate, ethylene glycol dioleate, PEG-3 dioleate, PEG-4 dioleate, etc.

As glyceryl esters of fatty acids, glyceryl stearate (glyceryl di-and/or tristearate) such as glyceryl 1, 3-distearate, glycerol dioleate, glyceryl dilaurate, glyceryl 1, 3-dipalmitate and a mixture thereof can in particular be cited.

As polyglycerol esters of fatty acids, the polyglycerol moiety may be derived from 2 to 10 glycerols, preferably 2 to 8 glycerols, or 2 to 6 glycerols, and/or the fatty acid may be C ₆-C ₂₂ fatty acid, and preferably C ₁₂-C ₂₂ fatty acid.

The polyglycerol esters of fatty acids may be selected from the mono-, di-, tri-or sesqui-esters of a linear or branched, saturated or unsaturated fatty acid, such as lauric acid, oleic acid, stearic acid, isostearic acid, capric acid, caprylic acid, palmitic acid, and myristic acid.

The polyglycerol esters of fatty acids may be selected from polyglyceryl mono-, di-, tri-or sesqui-caprylate comprising from 2 to 10 glycerol units, polyglyceryl mono-, di-, tri-or sesqui-caprate comprising from 2 to 10 glycerol units, polyglyceryl mono-, di-, tri-or sesqui-laurate comprising from 2 to 10 glycerol units, polyglyceryl mono-, di-, tri-or sesqui-myristate comprising from 2 to 10 glycerol units, polyglyceryl mono-, di-, tri-or sesqui-palmitate comprising from 2 to 10 glycerol units, polyglyceryl mono-, di-, tri-or sesqui-stearate comprising from 2 to 10 glycerol units, polyglyceryl mono-, di-, tri-or sesqui-isostearate comprising from 2 to 10 glycerol units, polyglyceryl mono-, di-, tri-or sesqui-oleate comprising from 2 to 10 glycerol units, and mixtures thereof, with the polyglycerol esters of fatty acids comprising 2 to 6 glycerol units and/or deriving from C ₁₂-C ₂₂ fatty acid being preferable.

The sorbitol esters of C ₆-C ₂₂ fatty acids and alkoxylated derivatives thereof can be selected from sorbitan tristearate, sorbitan trioleate and esters of fatty acids such as span 65, span 85 and alkoxylated sorbitan containing for example from 20 to 100 EO, such as for example polyethylene sorbitan trioleate (polysorbate 85) or the compounds marketed under the trade names Tween 20 or Tween 60 by Croda.

As esters of fatty acids and glucose or alkylglucose, in particular glucose palmitate, alkylglucose sesquistearates such as methylglucose sesquistearate, alkylglucose palmitates such as methylglucose or ethylglucose palmitate, methylglucoside fatty esters and more specifically the diester of methylglucoside and oleic acid (methyl glucose dioleate) , the mixed ester of methylglucoside and the mixture oleic acid/hydroxystearic acid (methyl glucose dioleate/hydroxystearate) , the ester of methylglucoside and isostearic acid (methyl glucose isostearate) , the ester of methylglucoside and lauric acid (Methyl glucose laurate) , the mixture of monoester and diester of methylglucoside and isostearic acid (Methyl glucose sesqui-isostearate) , the mixture of monoester and diester of methylglucoside and stearic acid (methyl glucose sesquistearate) and in particular the product marketed under the name Glucate SS by Lubrizol, and a mixture thereof can be cited.

As ethoxylated ethers of fatty acids and glucose or alkylglucose, ethoxylated ethers of fatty acids and methylglucose, and in particular the polyethylene glycol ether of the diester of methylglucose and stearic acid with about 20 moles of ethylene oxide (PEG-20 methyl glucose distearate) such as the product marketed under the name GLUCAM E-20 DISTEARATE by Lubrizol, the polyethylene glycol ether of the mixture of monoester and diester of methyl-glucose and stearic acid with about 20 moles of ethylene oxide (PEG-20 methyl glucose sesquistearate) and in particular the product marketed under the name GLUCAMATE SSE-20 by Lubrizol, and a mixture thereof, can for example be cited.

As sucrose esters, sucrose dilaurate, sucrose trilaurate, sucrose dioleate, sucrose trioleate, sucrose tristearate can be cited.

Preferably, the nonionic surfactant is selected from polyglycerol esters of fatty acids; especially polyglyceryl mono-, di-or tri-oleate comprising from 2 to 6 glycerol units, polyglyceryl mono-, di-or tri-isostearate comprising from 2 to 6 glycerol units, and mixtures thereof.

More preferably, the nonionic surfactant is selected from polyglyceryl-6 dioleate, polyglyceryl-2 oleate, polyglyceryl-2 triisostearate, and mixtures thereof.

Advantageously, the nonionic surfactant is present in an amount ranging from about 0.1 wt. %to about 15 wt. %, preferably from about 0.5 wt. %to about 10 wt. %, or from about 1 wt. %to about 5 wt. %, relative to the total weight of the composition.

Ionic surfactant

In the context, the term "ionic surfactant" means a surfactant bearing at least one anion or cation in the molecule, and non-limiting examples that can be mentioned are anionic surfactant, cationic surfactant, amphoteric surfactant, and zwitterionic surfactant.

The ionic surfactant according to the present invention is preferably chosen from an anionic surfactant. Further, the ionic surfactant according to the present invention is preferably lipophilic.

The anionic surfactant is chosen from alkyl sulfosuccinates, including mono-alkyl sulfosuccinates and di-alkyl sulfosuccinates.

Preferably, the alkyl sulfosuccinates present in the composition according to the present invention are selected from mono-or di-alkyl sulfosuccinates in which the alkyl radicals have 4 to 24 carbon atoms, preferably 6 to 18 carbon atoms, particularly preferably 6 to 14 carbon atoms. Different or identical alkyl radicals can be present in one molecule of di-alkyl sulfosuccinate, with identical being preferred. The alkyl radicals can be linear, branched or cyclic, saturated or unsaturated, and substituted or unsubstituted.

The sulfosuccinates may be chosen from alkali metal salts such as the sodium or potassium salt and preferably the sodium salt, ammonium salts, amine salts and in particular amino alcohol salts or alkaline-earth metal salts such as the magnesium salts.

According to a particular embodiment of the invention, the sulfosuccinates are chosen from the salts of alkali metals and even more particularly the sodium salt, including disodium salts for mono-alkyl sulfosuccinates and sodium salts for di-alkyl sulfosuccinates.

Preferably, the alkyl sulfosuccinate is selected from mono- or di-alkyl sulfosuccinates in which the alkyl radicals have 6 to 14 carbon atoms and the counterion to the sulfonic acid group is selected from alkali metal cations and ammonium ions.

Non-limiting examples of the di-alkyl sulfosuccinates are diethylhexyl sodium sulfosuccinate, dinonyl sodium sulfosuccinate, diisononyl sodium sulfosuccinate, dioctyl sodium sulfosuccinate, diheptyl sodium sulfosuccinate, dihexyl sodium sulfosuccinate, dicapryl sodium sulfosuccinate, didecyl sodium sulfosuccinate, diundecyl sodium sulfosuccinate, dilauryl sodium sulfosuccinate, dicocoyl sodium sulfosuccinate, ditridecyl sodium sulfosuccinate, dipropylheptyl sodium sulfosuccinate, dicyclohexyl sodium sulfosuccinate, ammonium diethylhexyl sulfosuccinate, ammonium dinonyl sulfosuccinate, ammonium diisononyl sulfosuccinate, ammonium dioctyl sulfosuccinate, ammonium diheptyl sulfosuccinate, ammonium dihexyl sulfosuccinate, ammonium dicapryl sulfosuccinate, ammonium didecyl sulfosuccinate, ammonium diundecyl sulfosuccinate, ammonium dilauryl sulfosuccinate, ammonium dicocoyl sulfosuccinate, ammonium ditridecyl sulfosuccinate, ammonium dipropylheptyl sulfosuccinate, ammonium dicyclohexyl sulfosuccinate, diethylhexyl potassium sulfosuccinate, dinonyl potassium sulfosuccinate, diisononyl potassium sulfosuccinate, dioctyl potassium sulfosuccinate, diheptyl potassium sulfosuccinate, dihexyl potassium sulfosuccinate, dicapryl potassium sulfosuccinate, didecyl potassium sulfosuccinate, diundecyl potassium sulfosuccinate, dilauryl potassium sulfosuccinate, dicocoyl potassium sulfosuccinate, ditridecyl potassium sulfosuccinate, dipropylheptyl potassium sulfosuccinate, dicyclohexyl potassium sulfosuccinate, with diethylhexyl sodium sulfosuccinate being very particularly preferred.

Non-limiting examples of the mono-alkyl sulfosuccinates are diammonium lauryl sulfosuccinate, disodium cetearyl sulfosuccinate, disodium cetyl sulfosuccinate, disodium coco-sulfosuccinate, disodium isodecyl sulfosuccinate, disodium isostearyl sulfosuccinate, disodium lauryl sulfosuccinate, disodium oleyl sulfosuccinate, disodium stearyl sulfosuccinate, disodium tridecyl sulfosuccinate, with disodium lauryl sulfosuccinate being very particularly preferred.

Preferably, the anionic surfactant is chosen from dialkyl sulfosuccinates in which each alkyl has 6 to 18 carbon atoms, preferably 6 to 14 carbon atoms and the two alkyls are the same. In one example, the anionic surfactant is diethylhexyl sodium sulfosuccinate.

In order to satisfy the safety standard and not damage the health of the users, a relatively lower amount of the ionic surfactant is required. Advantageously, the ionic surfactant is present in an amount of lower than about 5.0 wt. %, preferably lower than about 3.0 wt. %, or lower than about 1.5 wt. %, and even ranges from about 0.1 wt. %to about 1.0 wt. %, relative to the total weight of the composition.

Reverse micelle system

By means of the system comprising the above the continuous oily phase, the surfactant combination and the polar phases, reverse micelles can form in the present composition. The reverse micelles render the composition of the present invention to exhibit a transparent appearance, and to be thermodynamically stable over time.

Comparing with the reverse micelle comprising water cores, the reverse micelles comprising DES cores can carry higher hydrophilic active ingredients, since the DES, per se, are hydrophilic active ingredients. Further, as a special solvent, the DES can further dissolve other hydrophilic active ingredients, e.g. plant extracts, dyes and preservatives.

In the composition comprising said reverse micelles, the hydrophilic active ingredients are present in an amount ranging from about 0.01 wt. %to about 5.0 wt. %, preferably from about 0.1 wt. %to about 2.0 wt. %, or from about 0.2 wt. %to about 1.0 wt. %, relative to the total weight of the composition.

Additional ingredients

The composition according to the present invention may also comprise an effective amount of other ingredients, known previously elsewhere in compositions for conditioning keratin fibers, e.g., fragrances, which are present in an amount ranging from about 0.01 wt.%to about 5 wt. %, preferably from about 0.1 wt. %to about 3 wt. %, or from about 0.3 wt.%to about 2 wt. %, relative to the total weight of the composition.

Oily product

According to the second aspect of the present invention, an oily product comprising or consisting of the above transparent composition is provided. When the oily product consists of the above transparent composition, it means that the above transparent composition is in the form of an oily product. According to the present invention, the oily product may be in the form of bi-phasic oily product or homogeneous oily product.

Bi-phasic oily product

In the context, the term "bi-phasic oily product" is a product having two phases or layers from naked eyes.

The bi-phasic oily product according to the present invention comprises a continuous oily phase, comprising at least one oil; and a polar phase comprising deep eutectic solvents to carry an effective amount of hydrophilic active ingredients for conditioning keratin fibers. The types of the oily phase, deep eutectic solvent and hydrophilic active ingredient are defined as above.

In one embodiment, the bi-phasic oily product according to the present invention comprises one oily phase and one polar phase.

In the bi-phasic oily product according to the present invention, the at least one oil is present in an amount ranging from about 10 wt. %to about 90 wt. %, preferably from about 25 wt. %to about 80 wt. %, or from about 40 wt. %to about 70 wt. %, relative to the total weight of the composition.

In one embodiment, the bi-phasic oily product according to the present invention does not comprise any surfactants.

In one embodiment, the deep eutectic solvent including a hydrogen bond donor and a hydrogen bond donor is present in an amount ranging from about 8 wt. %to about 50 wt. %, preferably from about 12 wt. %to about 35 wt. %, or from about 15 wt. %to about 25 wt. %, relative to the total weight of the composition. The weight ratio of the hydrogen bond acceptors to the hydrogen bond donors is defined as above.

By means of the deep eutectic solvent comprising hydrophilic active ingredients, the bi-phasic oily product exhibits a transparent appearance, and is thermodynamically stable over time. In one embodiment, the bi-phasic oily product is in the form of hair oils, including leave-on hair oils and rinse-off hair oils, and preferably leave-on hair oils.

Homogeneous oily product

In the context, the term "homogeneous oily product" is a homogeneous and transparent product from naked eyes and is not layered at room temperature.

The homogeneous oily product according to the present invention comprises a continuous oily phase, comprising at least one oil; dispersed polar phases comprising deep eutectic solvents to carry an effective amount of hydrophilic active ingredients for conditioning keratin fibers; and a surfactant combination consisting of at least one nonionic surfactant and optionally at least one ionic surfactant which is preferably an anionic surfactant. The types of the oily phase, deep eutectic solvent, hydrophilic active ingredient, and surfactant combination are defined as above.

In one embodiment, the homogeneous oily product according to the present invention comprises one oily phase and a plurality of polar phases dispersed in said oily phase.

In the homogeneous oily product according to the present invention, the above reverse micelles are formed, and the at least one oil is present in an amount ranging from about 80 wt. %to about 99 wt. %, preferably from about 85 wt. %to about 98 wt. %, or from about 90 wt. %to about 96 wt. %, relative to the total weight of the composition.

In one embodiment, the deep eutectic solvent including a hydrogen bond donor and a hydrogen bond donor is present in an amount ranging from about 0.01 wt. %to about 5 wt. %, preferably from about 0.05 wt. %to about 3 wt. %, or from about 0.1 wt. %to about 2 wt. %, relative to the total weight of the composition. The weight ratio of the hydrogen bond acceptors to the hydrogen bond donors is defined as above.

By means of specific reverse micelle system comprising the deep eutectic solvent, the homogeneous oily product exhibits a transparent appearance, and is thermodynamically stable over time. In one embodiment, the homogeneous oily product is in the form of hair oils, including leave-on hair oils and rinse-off hair oils, and preferably leave-on hair oils.

Preparation and use

The composition according to the present invention can be prepared by mixing ingredients of the oily phase, the polar phase, and the surfactants, if present, as well as additional ingredient (s) , as explained above.

The method and means to mix the above various ingredients are not limited. Any conventional method and means can be used to mix the above various ingredients to prepare the composition according to the present invention.

The term “clear” is interchangeable with the term “transparent” for purposes of the instant disclosure.

The presence of reverse micelles can be confirmed by measurement of the sizes of reverse micelles by Dynamic Light Scattering (DLS) .

The use of the composition can be done on wet or dry hair.

According to the third aspect of the present invention, it relates to a cosmetic process for conditioning keratin fibers comprising applying the composition as described above onto the keratin fibers.

According to the fourth aspect of the present invention, it relates to use of the composition of the present invention as hair oils, including leave-on hair oils and rinse-off hair oils.

The following examples are given by way of illustration of the present invention and shall not be interpreted as limiting the scope.

EXAMPLES

Main raw materials used, trade names and supplier thereof were listed in Table 1.

Table 1

Inventive Example 1

A bi-phasic hair oil according to inventive formula IE. 1 was prepared with the ingredients listed in Table 2 (the contents were expressed as weight percentages of ingredients with regard to the total weight of the hair oil, unless otherwise indicated) , wherein water came from the ingredients of the polar phase as an impurity:

Table 2

Preparation procedure:

The composition was prepared from the following steps:

1) mixing betaine and lactic acid under the amounts as shown in Table 2;

2) heating the mixture at around 80 ℃, and stirring for a few minutes to obtain a transparent and stable solution;

3) preparing the oil phase by mixing and stirring thoroughly the oils;

4) preparing the polar phase by mixing the pre-formulated lactic acid/betaine DES with propylene glycol; and

5) mixing the oil phase with the polar phase.

Evaluation:

The stability of the hair oil obtained was evaluated by maintaining the hair oil at 4℃, room temperature (20℃) , or 45℃ for 2 months and observing with naked eyes to check whether the hair oil was transparent. It would be evaluated as stable if the hair oil tested was transparent under all of 4℃, room temperature (20℃) , and 45℃ for 2 months, otherwise, it would be evaluated as unstable.

The appearance of the hair oil obtained was observed with naked eyes.

The result was summarized in Table 3.

Table 3

From Tables 2-3, it could be seen that the bi-phasic hair oil of IE. 1 exhibited transparent appearance, and was thermodynamically stable over time.

Inventive Examples 2-3 and Comparative Example 1

The homogeneous hair oils according to inventive formulas IEs. 2-3 and comparative formula CE. 1 were prepared with the ingredients listed in Table 4 (the contents were expressed as weight percentages of ingredients with regard to the total weight of each hair oil, unless otherwise indicated) , wherein water came from the ingredients of the polar phase as an impurity:

Table 4

Preparation procedure:

The compositions were prepared from the following steps:

1) mixing betaine and lactic acid under the amounts as shown in Table 4;

2) heating the mixture at around 80 ℃, and stirring for a few minutes to obtain transparent and stable solutions of the polar phase;

3) preparing the oil phase by mixing and stirring thoroughly the oils;

4) adding the surfactants into the oil phase, and stirring thoroughly at room temperature to fully dissolve the surfactants in the oils; and

5) adding the pre-formulated polar phase into the surfactant containing oil phase, and stirring thoroughly at room temperature to obtain transparent and homogeneous liquids.

Evaluation:

The stability and appearance of the homogeneous hair oils obtained were evaluated as described above.

The results were summarized in Table 5.

Table 5

From Tables 4-5, it could be seen that each of the hair oils of IEs. 2-3 exhibited transparent appearance, and was thermodynamically stable over time.

By contrast, the composition which did not comprise the deep eutectic solvent of the present invention leaded to phase separation, i.e. could not obtain the desirable transparent appearance.

Moreover, from Tables 4-5, it could be seen that no or only an amount of 0.15 wt. %of the anionic surfactant in the reverse micelle system encapsulated an amount of as high as 0.38 wt. %of hydrophilic active ingredients in the composition and brought the composition a stably transparent appearance. This amount of hydrophilic active ingredients was higher than that from the same reverse micelle system comprising water cores. The amount of as low as 0.15 wt. %of the anionic surfactant satisfied the safety standard and did not damage the health of the users.

Measurement of the sizes of reverse micelles by Dynamic Light Scattering

The sizes of the formulated reverse micelles were characterized using Brookhaven dynamic light scattering (DLS) equipment. The DLS experiment measured the hydrodynamic radius of the reverse micelles, and included the solvation effects. As the viscosity of the oil base was higher than the maximum value suggested by Brookhaven, pure isododecane was taken as representative oil simplex for the study of the reverse micelle systems using DLS. The main experimental parameters set for the DLS experiments were listed in Table 6.

Table 6. Summary of the main parameters set for DLS characterisations.

In the following Table 7, Samples 1-2 corresponded to IEs. 2-3 respectively, but the oil bases were simplified using the single isododecane. All of the results of average effective diameter and average polydispersity were obtained from at least three measurements.

The Samples 1-2 were prepared with the ingredients listed in Table 7 (the contents were expressed as weight percentages of ingredients with regard to the total weight of each sample, unless otherwise indicated) :

Table 7

Definition of the Polydispersity Index (PDI) was a dimensionless measure of the broadness of the size distribution calculated from the cumulants analysis. This value should range from 0 to 1. If this value was higher than 1, then the distribution was too much polydisperse, and thus the sample might not be suitable for measurement by DLS.

From the above Table 7, together with Figs. 1-2, it could be seen that each of Samples 1-2 obtained an average polydispersity of lower than 1. Thus, it was demonstrated that reverse micelles having the average effective diameters as shown in Table 7 were indeed formed and were stable over time in the homogeneous hair oils of IEs. 2-3.

By means of the stable reverse micelles formed in the homogeneous hair oils of the present invention, the homogeneous hair oils maintained the transparent appearance over time, and an effective amount of the hydrophilic active ingredients, e.g. 0.25 wt. %or even higher, relative to the total weight of the composition, could be contained in the dispersed polar phases of the transparent composition of the present invention.

Claims

A transparent composition for conditioning keratin fibers, preferably hair, comprising:

a) a continuous oily phase, comprising at least one oil, and

b) one or more polar phases, comprising deep eutectic solvents to carry an effective amount of hydrophilic active ingredients for conditioning keratin fibers, wherein the deep eutectic solvent includes a hydrogen bond donor and a hydrogen bond acceptor.
The transparent composition according to claim 1, wherein the hydrogen bond donor is an organic acid, and is preferably selected from lactic acid, glycolic acid, salicylic acid, nicotinic acid, oxalic acid, citric acid, tartaric acid, malic acid, adipic acid, galacturonic acid, and gluconic acid; more preferably, the hydrogen bond donor is selected from lactic acid, glycolic acid, salicylic acid and citric acid; in particular, the hydrogen bond donor is chosen from lactic acid.
The transparent composition according to claim 1, wherein the hydrogen bond acceptor is chosen from quaternary salts, including quaternary ammonium salts and quaternary phosphonium salts, e.g. betaine and choline chloride; polyols derived from sugars, e.g. trehalose, xylitol, glucose, and panthenol; and amino acids, e.g. alanine, glycine, histidine, and proline; preferably, the hydrogen bond acceptor is selected from betaine, trehalose, glucose, and panthenol; in particular, the hydrogen bond acceptor is chosen from betaine.
The transparent composition according to any one of the preceding claims, wherein the deep eutectic solvent is present in an amount ranging from 0.01 wt. %to 50 wt. %, preferably from 0.05 wt. %to 35 wt. %, or from 0.1 wt. %to 25 wt. %, relative to the total weight of the composition; and/or the weight ratio of the hydrogen bond acceptors to the hydrogen bond donors ranges from 1∶20 to 1∶0.1, preferably from 1∶13 to 1∶0.5, or from 1∶10 to 1∶0.8.
The transparent composition according to any one of the preceding claims, wherein the at least one oil is selected from hydrocarbon oils, triglycerides, silicone oils, ether oils, and mixtures thereof; preferably is selected from hydrocarbon oils, silicone oils, and mixtures thereof; the at least one oil is present in an amount ranging 10 wt. %to 99 wt. %, preferably from 25 wt. %to 97 wt. %, or from 50 wt. %to 95 wt. %, relative to the total weight of the composition.
The transparent composition according to any one of the preceding claims, the polar phases comprise less than 10 wt. %of water, and particularly less than 6 wt. %of water, relative to the weight of the deep eutectic solvent.
The transparent composition according to any one of the preceding claims, wherein the polar phases comprise from 0.1 wt. %to 40 wt. %, preferably from 1 wt. %to 30 wt. %, or from 5 wt. %to 25 wt. %of C ₂-C ₈ lower polyols or monoalcohols, relative to the total weight of the composition, and the polyol is selected from butylene glycol, propylene glycol, pentylene glycol, isoprene glycol, caprylyl glycol, glycerol, polyethylene glycols, and mixtures thereof.
The transparent composition according to any one of the preceding claims, further comprising a surfactant combination consists of at least one nonionic surfactant and optionally at least one anionic surfactant, wherein reverse micelles are formed in the composition.
The transparent composition according to claim 8, wherein the nonionic surfactant comprises at least one C ₆-C ₂₂ alkyl chain, such as one, two or three C ₆-C ₂₂ alkyl chains, wherein the alkyl chain in the nonionic surfactant is preferably C ₁₂-C ₂₂ alkyl chain; preferably, the nonionic surfactant further has an HLB value ranging from 0 to 10.
The transparent composition according to claim 9, wherein the nonionic surfactant is selected from polyglyceryl mono-, di-or tri-oleate comprising from 2 to 6 glycerol units, polyglyceryl mono-, di-or tri-isostearate comprising from 2 to 6 glycerol units, and mixtures thereof; and preferably is selected from polyglyceryl-6 dioleate, polyglyceryl-2 triisostearate, polyglyceryl-2 oleate and mixtures thereof.
The transparent composition according to claim 8, wherein the anionic surfactant is chosen from mono-or di-alkyl sulfosuccinates, and is preferably chosen from di-alkyl sulfosuccinates with two identical alkyls, in which the alkyl radicals have 4 to 24 carbon atoms, preferably 6 to 18 carbon atoms, and particularly preferably 6 to 14 carbon atoms.
The transparent composition according to any one of claims 8-11, wherein the surfactant combination consists of

polyglyceryl-2 oleate and polyglyceryl-2 triisostearate,

diethylhexyl sodium sulfosuccinate and polyglyceryl-2 oleate,

diethylhexyl sodium sulfosuccinate and polyglyceryl-2 triisostearate, or

diethylhexyl sodium sulfosuccinate, polyglyceryl-2 oleate and polyglyceryl-2 triisostearate.
The transparent composition according to any one of claims 8-12, wherein the surfactant combination is present in an amount ranging from 0.1 wt. %to 20 wt. %, preferably from 0.5 wt. %to 10 wt. %, or from 1 wt. %to 5 wt. %, relative to the total weight of the composition; the ionic surfactant is present in an amount of lower than 5.0 wt.%, preferably lower than 3.0 wt. %, or lower than 1.5 wt. %, and even ranges from 0.1 wt.%to 1.0 wt. %, relative to the total weight of the composition.
The transparent composition according to any one of claims 8-13, wherein the hydrophilic active ingredients are present in an amount ranging from 0.01 wt. %to 5.0 wt.%, preferably from 0.1 wt. %to 2.0 wt. %, or from 0.2 wt. %to 1.0 wt. %, relative to the total weight of the composition.
The transparent composition according to any one of claims 1-7, which is in the form of a bi-phasic oily product, e.g., hair oils, including leave-on hair oils and rinse-off hair oils, and preferably leave-on hair oils, wherein the at least one oil is present in an amount ranging from 10 wt. %to 90 wt. %, preferably from 25 wt. %to 80 wt. %, or from 40 wt. %to 70 wt. %, relative to the total weight of the composition; preferably, the deep eutectic solvent including a hydrogen bond donor and a hydrogen bond donor is present in an amount ranging from 8 wt. %to 50 wt. %, preferably from 12 wt. %to 35 wt. %, or from 15 wt. %to 25 wt. %, relative to the total weight of the composition.
The transparent composition according to any one of claims 8-14, which is in the form of a homogeneous oily product, e.g., hair oils, including leave-on hair oils and rinse-off hair oils, and preferably leave-on hair oils, wherein the at least one oil is present in an amount ranging from 80 wt. %to 99 wt. %, preferably from 85 wt. %to 98 wt. %, or from 90 wt. %to 96 wt. %, relative to the total weight of the composition; preferably, the deep eutectic solvent including a hydrogen bond donor and a hydrogen bond donor is present in an amount ranging from 0.01 wt. %to 5 wt. %, preferably from 0.05 wt. %to 3 wt.%, or from 0.1 wt. %to 2 wt. %, relative to the total weight of the composition.