CN118541135A - Composition for conditioning keratin fibres - Google Patents

Abstract

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

Description

Composition for conditioning keratin fibers

Technical Field

The present invention relates to compositions for conditioning keratinous fibers, especially human keratinous fibers, such as the hair.

Background Art

Hair is often damaged and weakened due to the action of external atmospheric factors (eg light, weather) and/or mechanical or chemical treatments (eg brushing, combing, dyeing, bleaching, perming and/or straightening).

There are many products containing lipophilic active ingredients that can be used to condition hair. For example, many hair oil products contain lipophilic active ingredients. In order to meet the needs of different consumers, cosmetic companies are keen to enrich the product category of hair oil products. In the development process of hair oil products, it is a challenge to add hydrophilic active ingredients for conditioning hair, not to mention high levels of hydrophilic active ingredients. Therefore, this relatively low amount cannot meet the desired benefits to keratin fibers.

Furthermore, it is highly desirable to provide hair conditioning benefits using products that have a pleasing appearance, for example, products that have a clear appearance, and it is also desirable for products for conditioning hair to remain stable over time.

Therefore, there is still a need to develop compositions for conditioning keratin fibers, in particular human keratin fibers, such as hair, which contain relatively high amounts of hydrophilic active ingredients for conditioning the hair and improving sensory properties and which have a transparent appearance and remain stable over time, thereby providing long-term biological benefits to the keratin fibers.

Summary of the invention

In order to increase the hydrophilic active ingredients in keratin fiber conditioning products while maintaining a transparent appearance, we added a deep eutectic solvent (DES) to the conditioning products, such as hair oil, for delivering the hydrophilic active ingredients, wherein the components constituting the deep eutectic solvent are themselves active substances, and the deep eutectic solvent can also carry other active substances, such as 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 hair, comprising:

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

b) one or more polar phases, which contain a deep eutectic solvent to carry an effective amount of hydrophilic active ingredients for conditioning keratin fibers. As mentioned above, the expression "deep eutectic solvent to carry an effective amount of hydrophilic active ingredients for conditioning keratin fibers" means that the deep eutectic solvent itself is an active substance and can also carry other active substances, such as hydrophilic plant extracts, hydrophilic dyes, hydrophilic preservatives, etc.

Preferably, the polar phase comprises less than about 10 wt. % water, in particular less than about 6 wt. % water, relative to the weight of the deep eutectic solvent. More preferably, the polar phase comprises substantially no water, which means that the polar phase comprises trace amounts of water, i.e., water, if present, is contained as an impurity.

The transparent composition comprising an effective amount of a hydrophilic active ingredient provides the consumer with an active ingredient that nourishes keratin fibers and improves the sensory experience.

The deep eutectic solvent according to the present invention comprises a hydrogen bond donor and a hydrogen bond acceptor, both of which are physiologically beneficial active ingredients, and both of which are the above-mentioned hydrophilic active ingredients.

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

By the combination of surfactants, reverse micelles are formed in the composition, so that the composition has a transparent appearance and has thermodynamic stability over time. In the reverse micelle system, DES replaces water as the core inside. In addition, by the combination of surfactants, a relatively high amount of hydrophilic active ingredients is included. In addition, since DES itself is a hydrophilic active ingredient, the composition of the present invention usually carries a higher amount of active ingredients than the composition of the reverse micelle system containing a water core.

For the surfactant combination, in order to comply with safety standards and not to harm the health of the user, the surfactant combination is present in a relatively low amount, comprising at least one nonionic surfactant and optionally at least one ionic surfactant. In one embodiment, the amount of at least one ionic surfactant is not higher than about 1.0% by weight, relative to the total weight of the composition. Surprisingly, the inventors have found that even at very low amounts of ionic surfactants, reverse micelles can be formed and maintained in the composition of the present invention.

In principle, any oil suitable for treating keratin fibers can be used in the composition of the invention. In one embodiment, the at least one oil is chosen 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, which comprise, consist essentially of or consist of the above transparent composition in the form of a dual-phase oil or a homogeneous oil. For homogeneous oils, the above reverse micelles containing a specific surfactant combination are formed.

Other objects and features, aspects and advantages of the present invention will appear more clearly on reading the following detailed description and examples.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a multimodal size distribution of Sample 1 (corresponding to Example 2 of the present invention) from a Brookhaven dynamic light scattering (DLS) instrument.

FIG. 2 is a multimodal size distribution of Sample 2 (corresponding to Example 3 of the present invention) from a Brookhaven dynamic light scattering (DLS) instrument.

Each measurement of the Brookhaven DLS analyzer determines the average diameter (effective diameter) and distribution width (polydispersity) of the sample, where DLS measures a correlation function of intensity fluctuations, which can be converted mathematically into an intensity size distribution. The graph uses a numerical algorithm to describe the multi-peak intensity size distribution of the sample.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, unless otherwise indicated, the limits of ranges of values are included within the range, particularly within the expressions "between ... and ..." and "... to ...".

As used herein, the term "comprising" should be interpreted as covering all the specifically mentioned features as well as optional, additional, unspecified features.

As used herein, use of the term "comprising" also discloses embodiments in which no additional features other than those specifically mentioned are present (ie, "consisting of.").

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

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the invention belongs. When the definition of a term in this specification conflicts with the meaning commonly understood by those skilled in the art to which the invention belongs, the definition described herein shall prevail.

Unless otherwise indicated, all numerical values expressing amounts of ingredients and the like used in the specification and claims should be understood to be modified by the term “about.” Therefore, unless otherwise indicated, the numerical values and parameters described herein are approximate values that can vary depending on the desired properties to be obtained.

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

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

As used herein, the term "deep eutectic solvent" means that it exists in a liquid state at room temperature. Compared with ionic liquids, the preparation of deep eutectic solvents is simpler, faster, cheaper, and less toxic, and they are called "green solvents". Deep eutectic solvents are mainly composed of hydrogen bond donors and hydrogen bond acceptors to form binary and ternary systems of deep eutectic solvents. The most significant physical property of deep eutectic solvents is the reduction 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 the separation of natural organic components, or as a reaction solvent, etc.

As used herein, the term "reverse micelle" or "inverse micelle" is defined as follows: a surfactant is dissolved in a non-polar organic solvent. When its concentration exceeds the critical micelle concentration (CMC), micelles are formed in the organic solvent, which are called reverse micelles or reverse micelles. In the reverse micelle, the non-polar groups of the surfactant are in contact with the non-polar organic solvent on the outside, while the polar groups are arranged on the inside to form a polar core. This polar core has the ability to dissolve polar substances. When the polar core contains water, a "water pool" or "water core" is formed. The reverse micelle is a nanoscale aggregate and a transparent and thermodynamically stable W/O system.

As used herein, the term "lipophilic" refers to a substance or material that is capable of being dissolved or dispersed in an oil phase at 25°C to obtain a macroscopically homogeneous phase.

As used herein, the term "effective amount" refers to the amount of hydrophilic active ingredients contained in the polar phase of the composition, which is sufficient to effectively condition keratin fibers. According to the present invention, the effective amount can be about 0.01% by weight or even higher, such as about 0.05% by weight, about 0.1% by weight, about 0.15% by weight, about 0.2% by weight, about 0.25% by weight, about 0.30% by weight, about 0.35% by weight, about 0.40% by weight, about 0.45% by weight, about 0.5% by weight, about 0.6% by weight, about 0.7% by weight, about 0.8% by weight, about 1.0% by weight, about 1.5% by weight, about 2.0% by weight, about 2.5% by weight, about 3.0% by weight, about 4.0% by weight, about 5.0% by weight, relative to the total weight of the composition.

Oil phase

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

The "oil" herein refers to a fatty compound or substance that is in liquid or pasty (non-solid) form at room temperature (25°C) and atmospheric pressure (760 mmHg).

As the one or more oils, oils generally used in cosmetics may be used alone or in combination. The one or more oils may be volatile or nonvolatile, preferably nonvolatile.

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

The oils may be of vegetable or animal origin as well as synthetic oils.

As examples of vegetable oils, mention may be made of, for example, linseed oil, camellia oil, macadamia oil, corn oil, mink oil, olive oil, avocado oil, camellia 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 oil is preferably a liquid ester of a saturated or unsaturated, linear or branched C ₁ -C ₂₆ aliphatic monoacid or polyacid and a saturated or unsaturated, linear or branched C ₁ -C ₂₆ aliphatic monohydric alcohol or polyhydric alcohol, wherein the total number of carbon atoms of the ester is greater than or equal to 10.

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

Among the monoesters of monoacids and monoalcohols, mention may be made of ethyl palmitate, ethylhexyl 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.

Also useful are esters of _C4 - _C22 di- or tricarboxylic acids with _C1 - _C22 alcohols, and esters of mono-, di- or tricarboxylic acids with non-sugar _C4 - _C26 di-, tri-, tetra- or penta-hydroxy alcohols.

Mention may be made in particular 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; tricaprylin; trioctyldodecyl citrate; trioleyl citrate; neopentyl glycol diheptanoate; diethylene glycol diisononanoate.

As ester oils, sugar esters and diesters of C ₆ -C ₃₀ and preferably C ₁₂ -C ₂₂ fatty acids can be used. It should be remembered that the term "sugar" refers to oxygen-containing hydrocarbon compounds, which contain multiple alcohol functions, with or without aldehyde or ketone functions, and contain at least 4 carbon atoms. These sugars can be monosaccharides, oligosaccharides or polysaccharides.

Examples of suitable sugars that may be mentioned include sucrose, glucose, galactose, ribose, fucose, maltose, fructose, mannose, arabinose, xylose and lactose, and derivatives thereof, in particular alkyl derivatives, such as methyl derivatives, for example methyl glucose.

Sugar esters of fatty acids may be chosen in particular from esters or ester mixtures of the abovementioned sugars with linear or branched, saturated or unsaturated C ₆ -C ₃₀ fatty acids and preferably C ₁₂ -C ₂₂ fatty acids. If they are unsaturated, these compounds may have one to three conjugated or nonconjugated carbon-carbon double bonds.

The esters according to this variant may also be chosen 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, in particular, oleyl palmitate, oleostearate and palmitostearate mixed esters, and also pentaerythritol tetraethylhexanoate.

More particularly, use is made of monoesters and diesters and in particular mono- or dioleates, stearates, behenates, oleopalmitates, linoleates, linolenates and oleostearates of sucrose, glucose or methylglucose.

An example that may be mentioned is the company Amerchol A product sold under the name DO, which is methyl glucose dioleate.

As examples of preferred 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 octanoate/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, tri(2-ethylhexanoin)glyceryl, pentaerythritol tetra(2-ethylhexanoate), 2-ethylhexyl succinate, diethyl sebacate, and mixtures thereof.

As examples of artificial triglycerides, there may be mentioned, for example, caprylic/capric triglyceride, trimyristin, tripalmitin, trilinolenic acid, trilaurin, tricaprin, tricaprylin and tri(capric/caprylic/linolenic)glyceride.

The ether hydrocarbon-based oil, also called ether oil, may be volatile or non-volatile, preferably non-volatile.

The ether hydrocarbon-based oil is an oil having the formula R ₁ OR ₂ , wherein R ₁ and R ₂ independently represent 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. R ₁ and R ₂ are preferably the same.

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

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

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

Advantageously, the ether oil is chosen from dicaprylyl ether, dicapryl ether, dilauryl ether, diisostearyl ether, dioctyl ether, nonylphenyl ether, dodecyl dimethyl butyl ether, cetyl dimethyl butyl ether, cetyl isobutyl ether and mixtures thereof.

Preferably, it is selected from dicaprylyl ether, didecyl ether, dilauryl ether, diisostearyl ether, dicaprylyl ether and mixtures thereof. Dicaprylyl ether is most particularly suitable for use.

As examples of silicone oils, there may be mentioned, for example, linear organopolysiloxanes such as dimethylpolysiloxane, methylphenylpolysiloxane, methylhydrogenpolysiloxane, etc.; cyclic organopolysiloxanes such as cyclohexasiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, etc.; and mixtures thereof.

Preferably, the silicone oil is chosen from liquid polydialkylsiloxanes, especially liquid polydimethylsiloxane (PDMS), and liquid polyorganosiloxanes comprising at least one aromatic group.

These silicone oils may also be organomodified. Organomodified silicones that can be used according to the invention are silicone oils as defined above and that contain in their structure one or more organofunctional groups linked via hydrocarbon groups.

Organopolysiloxanes are defined in more detail in Walter Noll, Chemistry and Technology of Silicones (1968), Academic Press. They can be volatile or nonvolatile.

When they are volatile, the silicones are more particularly chosen from silicones having a boiling point ranging from 60° C. to 260° C., even more particularly from:

(i) Cyclic polydialkylsiloxanes containing 3 to 7 silicon atoms, preferably 4 to 5 silicon atoms. These are, for example, octamethylcyclotetrasiloxane, which is marketed in particular by Union Carbide as Volatile 7207 or sold by Rhodia 70045 V2, decamethylcyclopentasiloxane, is marketed by Union Carbide as Volatile 7158, sold by Rhodia 70045V5, and dodecamethylcyclopentasiloxane, sold under the name Silsoft 1217 by Momentive Performance Materials, and mixtures thereof. Mention may also be made of cyclic copolymers of the dimethylsiloxane/methylalkylsiloxane type, such as Silicone sold by the company Union Carbide. FZ 3109, which has the following formula:

Mention may also be made of mixtures of cyclic polydialkylsiloxanes with organosilicon compounds, for example a mixture of octamethylcyclotetrasiloxane with tetratrimethylsilylpentaerythritol (50/50) and a mixture of octamethylcyclotetrasiloxane with oxy-1,1′-bis(2,2,2′,2′,3,3′-hexatrimethylsiloxy)neopentane;

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

Nonvolatile polydialkylsiloxanes may also be used. These nonvolatile silicones are more particularly chosen from polydialkylsiloxanes, among which mention may mainly be made of polydimethylsiloxanes containing trimethylsilyl end groups.

Among these polydialkylsiloxanes, mention may be made, without limitation, of the following commercial products:

- 47 and 70 047 series sold by Rhodia Oil or Oil, for example oil 70 047V500 000;

-Sold by Rhodia Series of oils;

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

-From General Electric Oil and certain oils from General Electric's SF series (SF 96, SF 18).

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

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

- 70 641 series from Rhodia Oil;

-From Rhodia 70 Oils of the 633 and 763 series;

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

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

- Certain oils from General Electric's SF series, such as SF 1023, SF 1154, SF 1250, and SF 1265.

The organomodified liquid silicones may contain in particular polyethylene oxide and/or polypropylene oxide groups. Mention may be made, therefore, of silicone KF-6017 proposed by Shin-Etsu and of oil VIZO from the company Union Carbide. L722 and L77.

The hydrocarbon oil 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, such as isohexadecane, isododecane and isodecane; and

- straight-chain or branched hydrocarbons containing more than 16 carbon atoms, such as liquid paraffin, liquid petrolatum, polydecene and hydrogenated polyisobutylene (e.g. ) and squalane.

As preferred examples of hydrocarbon oils, there may be mentioned, for example, straight-chain or branched hydrocarbons such as isohexadecane, isododecane, squalane, mineral oils (e.g., liquid paraffin), paraffins, vaseline or petrolatum, naphthalene and the like; hydrogenated polyisobutene, isoeicosane and decene/butene copolymers; and mixtures thereof.

As an example, the oil is chosen from branched alkane oils containing 8 to 20 carbon atoms and better still 10 to 16 carbon atoms (e.g. isododecane), triglycerides (e.g. caprylic/capric triglyceride), ether hydrocarbon oils with _C8 - _C12 alkyl groups (e.g. dicaprylyl ether), polydimethylsiloxanes optionally containing dimethylsilanol end groups (e.g. polydimethylsiloxane, dimethiconol) and mixtures thereof.

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

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

Polar Phase

The compositions of the present invention comprise one or more polar phases of a deep eutectic solvent to carry an effective amount of hydrophilic active ingredients for conditioning keratinous fibers.

Preferably, the polar phase contains less than about 10 wt. % water, in particular less than about 6 wt. % water, relative to the weight of the deep eutectic solvent. More preferably, the polar phase contains substantially no water, or, if water is present, it is contained as an impurity. The term "substantially no water" means that the polar phase contains 5 wt. % or less water, relative to the weight of the deep eutectic solvent.

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

The term "polyol" is to be understood as any organic molecule comprising at least two free hydroxyl groups. Examples of polyols that may be mentioned include diols, such as butanediol, propylene glycol, pentanediol, isoprene glycol, octanediol, glycerol (ie glycerol) and polyethylene glycol.

If present, the water-miscible or at least partially water-miscible compound may comprise 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 %, based on the total weight of the composition.

Deep Eutectic Solvents (DES)

The deep eutectic solvent according to the present invention comprises a hydrogen bond donor (HBD) and a hydrogen bond acceptor (HBA), wherein both the hydrogen bond donor and the hydrogen bond acceptor are physiologically beneficial active ingredients, which are themselves the hydrophilic active ingredients contained in the composition of the present invention.

In particular, the expression "hydrophilicity" is interchangeable with the term "water-soluble", which is intended to characterize the ability of a compound to dissolve in water to a concentration at least equal to 0.1 g/l (yielding a macroscopically isotropic, transparent, colored or colorless solution) measured at 25° C. This solubility is in particular greater than or equal to 1 g/l.

Specifically, the hydrogen bond donor contained in the composition of the present invention is an acid, an alcohol, an amine or a carbohydrate, preferably an organic acid, 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 donor is selected from lactic acid, glycolic acid, salicylic acid and citric acid. In particular, the hydrogen bond donor is selected from lactic acid.

The hydrogen bond acceptor is selected from quaternary salts, including quaternary ammonium salts and quaternary phosphonium salts, such as betaine and choline chloride; polyols derived from sugars, such as trehalose, xylitol, glucose and panthenol; and some amino acids, such as 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 selected from betaine.

Advantageously, the weight ratio of the hydrogen bond acceptor to the hydrogen bond donor 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, for example 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 comprising hydrogen bond acceptors and hydrogen bond donors is present in an amount of about 0.01 wt % to about 50 wt %, preferably about 0.05 wt % to about 35 wt %, or about 0.1 wt % to about 25 wt %, relative to the total weight of the composition.

Other hydrophilic active ingredients

According to the invention, the polar phase may carry a certain amount of other hydrophilic active ingredients for conditioning keratin fibers in addition to the above-mentioned deep eutectic solvents, which means any natural or synthetic, usually organic compound that is soluble in the deep eutectic solvent. For example, other hydrophilic active ingredients may include plant extracts, dyes and preservatives.

As the hydrophilic plant extract, citrus fruit extract, aloe extract, lavender extract, bitter orange extract, ginkgo leaf extract, lemon extract, ginger extract and the like can be mentioned.

As hydrophilic dyes, mention may be made especially of synthetic or natural water-soluble dyes, including acidic or basic water-soluble dyes, such as 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 their combinations.

As the hydrophilic preservative, pentylene glycol, phenoxyethanol, salicylic acid, caprylyl glycol, sodium benzoate and the like may be mentioned in particular.

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 selected from anionic surfactants.

So far, there are few oily systems or phases that utilize reverse micelle technology to obtain a dispersed polar phase containing a deep eutectic solvent to carry an effective amount of hydrophilic active ingredients for conditioning keratin fibers.

By means of the surfactant combination, reverse micelles are formed in the composition, so that the composition has a transparent appearance and is thermodynamically stable over time. In addition, by means of the surfactant combination, a relatively high amount of hydrophilic active ingredients is included. In addition, since the DES itself is a hydrophilic active ingredient, the composition of the present invention generally carries a higher amount of active ingredients than a composition comprising a reverse micelle system containing a water core.

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

Nonionic surfactants

The nonionic surfactants according to the invention are preferably lipophilic.

As the nonionic surfactant, there may be mentioned those having at least one C ₆ -C ₂₂ alkyl chain, for example one, two or three C ₆ -C ₂₂ alkyl chains, and preferably, the nonionic surfactant also has an HLB value of about 0 to about 10.

As examples, mention may be made of esters of polyols with fatty acids having a saturated or unsaturated chain containing, for example, 6 to 22 carbon atoms, preferably 12 to 22 carbon atoms, and alkoxylated derivatives thereof, preferably having an alkylene oxygen number of 10 to 200, more preferably 10 to 100, such as glycerol esters of one or more C ₆ -C ₂₂ , preferably C ₁₂ -C ₂₂ fatty acids and alkoxylated derivatives thereof, preferably having an alkylene oxygen number of 10 to 200, more preferably 10 to 100; polyethylene glycol esters of one or more C ₆ -C ₂₂ , preferably C ₁₂ -C ₂₂ fatty acids and alkoxylated derivatives thereof, preferably having an alkylene oxygen number of 10 to 200, more preferably 10 to ₁₀₀ ; sorbitan esters of one or more C ₆ -C ₂₂ , preferably C ₁₂ -C ₂₂ fatty acids and alkoxylated derivatives thereof, preferably having an _alkylene oxygen number of 10 to 200, more preferably 10 to 100; , preferably sugar (sucrose, glucose, alkyl glucose) esters of C ₁₂ -C ₂₂ fatty acids and alkoxylated derivatives thereof, preferably having an alkylene oxygen number of 10 to 200, more preferably 10 to 100; and mixtures thereof.

Examples of ethoxylated fatty esters that may be mentioned include adducts of ethylene oxide with laurate, palmitate, stearate or behenate and mixtures thereof, in particular those containing 9 to 100 oxyethylene groups, for example 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, and the like.

As glycerol esters of fatty acids, mention may be made in particular of glyceryl stearates (glyceryl distearate and/or glyceryl tristearate), for example glyceryl 1,3-distearate, glyceryl dioleate, glyceryl dilaurate, glyceryl 1,3-dipalmitate and mixtures thereof.

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 a C ₆ -C ₂₂ fatty acid, preferably a C ₁₂ -C ₂₂ fatty acid.

The polyglycerol esters of fatty acids may be chosen from monoesters, diesters, triesters or sesquiesters of linear or branched, saturated or unsaturated fatty acids, 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 polyglycerol mono-, di-, tri- or sesquicaprylate containing 2 to 10 glycerol units, polyglycerol mono-, di-, tri- or sesquicaprylate containing 2 to 10 glycerol units, polyglycerol mono-, di-, tri- or sesquilaurate containing 2 to 10 glycerol units, polyglycerol mono-, di-, tri- or sesquimyristate containing 2 to 10 glycerol units, polyglycerol mono-, di-, tri- or sesquipalmitate containing 2 to 10 glycerol units, polyglycerol mono-, di-, tri- or sesquistearate containing 2 to 10 glycerol units, polyglycerol mono-, di-, tri- or sesquiisostearate containing 2 to 10 glycerol units, polyglycerol mono-, di-, tri- or sesquioleate containing 2 to 10 glycerol units, and mixtures thereof, wherein polyglycerol esters of fatty acids containing 2 to 6 glycerol units and/or derived from C ₁₂ -C ₂₂ fatty acids are preferred.

Sorbitol esters of _C6 - _C22 fatty acids and their alkoxylated derivatives may be chosen from sorbitan tristearate, sorbitan trioleate and fatty acid esters, such as Span 65, Span 85 and alkoxylated sorbitans containing, for example, 20 to 100 EO, such as polyoxyethylene sorbitan trioleate (polysorbate 85) or the compounds sold under the trade name Tween 20 or Tween 60 by Croda.

As esters of fatty acids with glucose or alkyl glucose, there may be mentioned in particular glucose palmitate, alkyl glucose sesquistearates such as methyl glucose sesquistearate, alkyl glucose palmitates such as methyl glucose or ethyl glucose palmitate, methyl glucoside fatty esters, more particularly the diesters of methyl glucoside with oleic acid (methyl glucose dioleate), the mixed esters of methyl glucoside with an oleic acid/hydroxystearic acid mixture (methyl glucose dioleate/hydroxystearate), the esters of methyl glucoside with isostearic acid (methyl glucose isostearate), the esters of methyl glucoside with lauric acid (methyl glucose laurate), a mixture of the mono- and diesters of methyl glucoside with isostearic acid (methyl glucose sesquiisostearate), a mixture of the mono- and diesters of methyl glucoside with stearic acid (methyl glucose sesquistearate), in particular the product sold under the name Glucate SS by Lubrizol, and mixtures thereof.

As ethoxylated ethers of fatty acids with glucose or alkyl glucose, there may be mentioned, for example, the ethoxylated ethers of fatty acids with methyl glucose, in particular the diester of methyl glucose with stearic acid and polyethylene glycol ether with about 20 mol of ethylene oxide (PEG-20 methyl glucose distearate), for example the product sold under the name GLUCAME-20 DISTEARATE by Lubrizol, mixtures of mono- and diesters of methyl glucose with stearic acid and polyethylene glycol ether with about 20 mol of ethylene oxide (PEG-20 methyl glucose sesquistearate), in particular the product sold under the name GLUCAMATESSE-20 by Lubrizol, and mixtures thereof.

Examples of the sucrose ester include sucrose dilaurate, sucrose trilaurate, sucrose dioleate, sucrose trioleate, and sucrose tristearate.

Preferably, the nonionic surfactant is chosen from polyglycerol esters of fatty acids; in particular polyglycerol mono-, di- or trioleates containing 2 to 6 glycerol units, polyglycerol mono-, di- or triisostearate containing 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 of about 0.1% to about 15% by weight, preferably about 0.5% to about 10% by weight, or about 1% to about 5% by weight relative to the total weight of the composition.

Ionic surfactants

In this context, the term "ionic surfactant" refers to a surfactant having at least one anion or cation in the molecule, and non-limiting examples that may be mentioned are anionic surfactants, cationic surfactants, amphoteric surfactants and zwitterionic surfactants.

The ionic surfactants according to the invention are preferably selected from anionic surfactants. Furthermore, the ionic surfactants according to the invention are preferably lipophilic.

The anionic surfactant is selected from alkyl sulfosuccinates, including monoalkyl sulfosuccinates and dialkyl sulfosuccinates.

Preferably, the alkyl sulfosuccinate salt present in the composition of the invention is selected from monoalkyl sulfosuccinate salts or dialkyl sulfosuccinate salts, wherein the alkyl group has 4 to 24 carbon atoms, preferably 6 to 18 carbon atoms, particularly preferably 6 to 14 carbon atoms. Different or identical alkyl groups may be present in one molecule of the dialkyl sulfosuccinate salt, preferably identical. The alkyl group may be linear, branched or cyclic, saturated or unsaturated, substituted or unsubstituted.

The sulfosuccinate salts may be selected from alkali metal salts, such as sodium or potassium salts, preferably sodium salts, ammonium salts, amine salts, in particular amino alcohol salts or alkaline earth metal salts, such as magnesium salts.

According to a particular embodiment of the invention, the sulfosuccinate salt is chosen from alkali metal salts, even more particularly sodium salts, including monoalkyl sulfosuccinate disodium salts and dialkyl sulfosuccinate sodium salts.

Preferably, the alkyl sulfosuccinate is selected from monoalkyl sulfosuccinate or dialkyl sulfosuccinate, wherein the alkyl group has 6 to 14 carbon atoms and the counterion of the sulfonic acid group is selected from alkali metal cations and ammonium ions.

Non-limiting examples of dialkyl sulfosuccinate salts are sodium diethylhexyl sulfosuccinate, sodium dinonyl sulfosuccinate, sodium diisononyl sulfosuccinate, sodium dioctyl sulfosuccinate, sodium diheptyl sulfosuccinate, sodium dihexyl sulfosuccinate, sodium dioctyl sulfosuccinate, sodium didecyl sulfosuccinate, sodium diundecyl sulfosuccinate, sodium dilauryl sulfosuccinate, sodium dicocoyl sulfosuccinate, sodium ditridecyl sulfosuccinate, sodium dipropylheptyl sulfosuccinate, sodium dicyclohexyl sulfosuccinate, ammonium diethylhexyl sulfosuccinate, ammonium dinonyl sulfosuccinate, ammonium diisononyl sulfosuccinate, ammonium dioctyl sulfosuccinate, ammonium diheptyl sulfosuccinate, ammonium dihexyl sulfosuccinate, ammonium dioctyl sulfosuccinate, ammonium didecyl sulfosuccinate, sodium diundecyl sulfosuccinate, sodium dilauryl sulfosuccinate, sodium dicocoyl sulfosuccinate, sodium ditridecyl sulfosuccinate, sodium dipropylheptyl sulfosuccinate, sodium dicyclohexyl sulfosuccinate, ammonium diethylhexyl sulfosuccinate, ammonium dinonyl sulfosuccinate, ammonium diisononyl sulfosuccinate, ammonium dioctyl sulfosuccinate, ammonium diheptyl sulfosuccinate, ammonium dihexyl sulfosuccinate, ammonium dioctyl sulfosuccinate, ammonium didecyl sulfosuccinate The present invention is preferably used in the following embodiments: sodium diundecyl sulfosuccinate, ammonium dilauryl sulfosuccinate, ammonium dicocoyl sulfosuccinate, ammonium ditridecyl sulfosuccinate, ammonium dipropylheptyl sulfosuccinate, ammonium dicyclohexyl sulfosuccinate, potassium diethylhexyl sulfosuccinate, potassium dinonyl sulfosuccinate, potassium diisononyl sulfosuccinate, potassium dioctyl sulfosuccinate, potassium diheptyl sulfosuccinate, potassium dihexyl sulfosuccinate, potassium dioctyl sulfosuccinate, potassium didecyl sulfosuccinate, potassium diundecyl sulfosuccinate, potassium dilauryl sulfosuccinate, potassium dicocoyl sulfosuccinate, potassium ditridecyl sulfosuccinate, potassium dipropylheptyl sulfosuccinate, potassium dicyclohexyl sulfosuccinate, among which sodium diethylhexyl sulfosuccinate is very particularly preferred.

Non-limiting examples of monoalkyl sulfosuccinates are diammonium lauryl sulfosuccinate, disodium cetearyl sulfosuccinate, disodium cetyl sulfosuccinate, disodium cocoyl 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 selected from dialkyl sulfosuccinate salts, wherein each alkyl group has 6 to 18 carbon atoms, preferably 6 to 14 carbon atoms, and the two alkyl groups are the same. In one example, the anionic surfactant is sodium diethylhexyl sulfosuccinate.

In order to meet safety standards and not to harm the health of the user, relatively low amounts of ionic surfactants are required. Advantageously, the ionic surfactant is present in an amount of less than about 5.0 wt %, preferably less than about 3.0 wt %, or less than about 1.5 wt %, even in a range of about 0.1 wt % to about 1.0 wt %, relative to the total weight of the composition.

Reverse micelle system

The system comprising the continuous oil phase, the surfactant combination and the polar phase can form reverse micelles in the composition of the present invention. The reverse micelles make the composition of the present invention present a transparent appearance and have thermodynamic stability over time.

Compared with reverse micelles containing a water core, reverse micelles containing a DES core can carry more hydrophilic active ingredients because DES itself is a hydrophilic active ingredient. In addition, DES, as a special solvent, can also dissolve other hydrophilic active ingredients, such as plant extracts, dyes and preservatives.

In the composition comprising the reverse micelle, the hydrophilic active ingredient is present in an amount of about 0.01 wt % to about 5.0 wt %, preferably about 0.1 wt % to about 2.0 wt %, or about 0.2 wt % to about 1.0 wt %, relative to the total weight of the composition.

Additional Ingredients

The composition according to the invention may also contain an effective amount of other ingredients previously known in compositions for conditioning keratin fibers, such as perfume, present in an amount ranging from about 0.01% to about 5% by weight, preferably from about 0.1% to about 3% by weight, or from about 0.3% to about 2% by weight relative to the total weight of the composition.

Oily products

According to a second aspect of the present invention, there is provided an oily product, which comprises or consists of the above-mentioned transparent composition. When the oily product consists of the above-mentioned transparent composition, it means that the above-mentioned transparent composition is in the form of an oily product. According to the present invention, the oily product can be in the form of a dual-phase oily product or a homogeneous oily product.

Two-phase oily products

In this context, the term "two-phase oily product" is a product which, to the naked eye, has two phases or layers.

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

In one embodiment, the dual-phase oily product according to the invention comprises an oil phase and a polar phase.

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

In one embodiment, the dual-phase oily product according to the invention does not comprise any surfactant.

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

By including a deep eutectic solvent of a hydrophilic active ingredient, the dual-phase oil product presents a transparent appearance and is thermodynamically stable over time. In one embodiment, the dual-phase oil product is in the form of a hair oil, including a leave-in hair oil and a rinse-out hair oil, and preferably a leave-in hair oil.

Homogenized oily products

In this context, the term "homogeneous oily product" refers to a product which is homogeneous and transparent to the naked eye and does not separate at room temperature.

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

In one embodiment, the homogenous oily product according to the invention comprises an oil phase and a plurality of polar phases dispersed in the oil phase.

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

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

By means of a specific reverse micelle system containing a deep eutectic solvent, the homogeneous oily product presents a transparent appearance and has thermodynamic stability over time. In one embodiment, the homogeneous oily product is in the form of a hair oil, including a leave-in hair oil and a rinse-out hair oil, and preferably a leave-in hair oil.

Preparation and use

The compositions according to the invention may be prepared by mixing the ingredients of the oil phase, polar phase and surfactant (if present) as described above, and one or more additional ingredients.

There is no limitation on the mixing method and means of the above-mentioned various components. Any conventional method and means can be used to mix the above-mentioned various components to prepare the composition according to the present invention.

For purposes of this disclosure, the term "clear" may be interchangeable with the term "transparent."

The presence of reverse micelles can be confirmed by measuring the size of the reverse micelles by dynamic light scattering (DLS).

The composition can be used on wet or dry hair.

According to a third aspect of the invention, it relates to a cosmetic method for conditioning keratin fibres comprising applying to the keratin fibres a composition as described above.

According to the fourth aspect of the present invention, it relates to the use of the composition of the present invention as hair oil, including leave-in hair oil and rinse-out hair oil.

The following examples are intended to illustrate the present invention but should not be construed as limiting the scope of the present invention.

Example

The main raw materials, trade names and suppliers used are listed in Table 1.

Table 1

Embodiment 1 of the present invention

A two-phase hair oil of formulation IE.1 according to the invention was prepared using the ingredients listed in Table 2 (unless otherwise specified, the contents are expressed as weight percentages of the ingredients relative to the total weight of the hair oil), wherein water as an impurity came from the ingredients of the polar phase:

Table 2

Preparation Procedure:

The composition is prepared by the following steps:

1) mixing betaine and lactic acid according to the amounts shown in Table 2;

2) heating the mixture to about 80°C and stirring for several minutes to obtain a transparent and stable solution;

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

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

5) Mix the oil phase with the polar phase.

Evaluate:

The stability of the obtained hair oil was evaluated as follows: the hair oil was placed at 4° C., room temperature (20° C.) or 45° C. for 2 months, and the hair oil was observed with the naked eye to see whether it was transparent. If the tested hair oil was transparent at 4° C., room temperature (20° C.) and 45° C. for 2 months, it was evaluated as stable, otherwise it was evaluated as unstable.

The appearance of the resulting hair oil was observed visually.

The results are summarized in Table 3.

Table 3

From Table 2-3, it can be seen that the dual-phase hair oil of IE.1 presents a transparent appearance and is thermodynamically stable over time.

Examples 2-3 of the present invention and comparative example 1

Homogenized hair oils according to the inventive formulations IE.2-3 and comparative formulation CE.1 were prepared using the ingredients listed in Table 4 (unless otherwise specified, the content is expressed as a weight percentage of the ingredient relative to the total weight of each hair oil), wherein water was derived from the polar phase as an impurity:

Table 4

Preparation Procedure:

The composition was prepared according to the following steps:

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

2) heating the mixture to about 80°C and stirring for several minutes to obtain a transparent and stable solution of the polar phase;

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

4) adding the surfactant to the oil phase and stirring sufficiently at room temperature to allow the surfactant to be fully dissolved in the oil; and

5) Add the pre-formulated polar phase to the oil phase containing the surfactant and stir well at room temperature to obtain a transparent homogeneous liquid.

Evaluate:

The resulting homogenized hair oils were evaluated for stability and appearance as described above.

The results are summarized in Table 5.

Table 5

nature IE.2 IE3 CE.1 stability Stable Stable Undissolved betaine powder Appearance Homogeneous and transparent Homogeneous and transparent Phase separation, deposition

From Tables 4-5, it can be seen that the hair oils of IE 2-3 all exhibit a transparent appearance and are thermodynamically stable over time.

In contrast, compositions not comprising the deep eutectic solvent of the present invention result in phase separation, ie, the desired transparent appearance cannot be obtained.

In addition, it can be seen from Tables 4-5 that the reverse micelle system without anionic surfactant or only 0.15 wt% of anionic surfactant can cover up to 0.38 wt% of hydrophilic active ingredients in the composition, and make the composition have a stable and transparent appearance. The amount of this hydrophilic active ingredient is higher than that of the reverse micelle system containing a water core. The amount of anionic surfactant as low as 0.15 wt% meets the safety standard and will not harm the health of the user.

Measurement of reverse micelle size by dynamic light scattering

Brookhaven dynamic light scattering (DLS) equipment was used to characterize the size of the formulated reverse micelles. The DLS experiment measures the hydrodynamic radius of the reverse micelles and includes the solvation effect. Since the viscosity of the oil base is higher than the maximum value recommended by Brookhaven, pure isododecane is used as a representative oil base to study the reverse micelle system using DLS. The main experimental parameter settings for the DLS experiment are listed in Table 6.

Table 6. Summary of main parameter settings for DLS characterization

In Table 7 below, samples 1-2 correspond to IE 2-3, respectively, but the oil base is simplified to use only isododecane. All the results of average effective diameter and average polydispersity are obtained from at least three measurements.

Samples 1-2 were prepared using the ingredients listed in Table 7 (unless otherwise stated, the content is expressed as weight percentage of the ingredient relative to the total weight of each sample):

Table 7

The polydispersity index (PDI) is defined as a dimensionless measure of the width of the size distribution calculated by cumulants analysis. The value should be between 0 and 1. If the value is above 1, the distribution is too dispersed and the sample may not be suitable for measurement by DLS.

From Table 7 above combined with Figures 1-2, it can be seen that samples 1-2 all obtained an average polydispersity lower than 1. Therefore, it is proved that reverse micelles with the average effective diameter shown in Table 7 are indeed formed in the homogenized hair oil of IE 2-3, and the reverse micelles remain stable over time.

Through the stable reverse micelles formed in the homogenous hair oil of the present invention, the homogenous hair oil maintains a transparent appearance over time, and an effective amount of a hydrophilic active ingredient, for example, 0.25 wt % or more relative to the total weight of the composition, can be contained in the dispersed polar phase of the transparent composition of the present invention.

Claims (16)

1. A transparent composition for conditioning keratin fibres, preferably the hair, comprising:

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

B) One or more polar phases comprising a deep eutectic solvent to carry an effective amount of hydrophilic active ingredient for conditioning keratin fibers, wherein the deep eutectic solvent comprises a hydrogen bond donor and a hydrogen bond acceptor.

2. The transparent composition according to claim 1, wherein the hydrogen bond donor is an organic acid, preferably selected from lactic acid, glycolic acid, salicylic acid, niacin, oxalic acid, citric acid, tartaric acid, malic acid, adipic acid, galacturonic acid, gluconic acid; more preferably, the hydrogen bond donor is selected from lactic acid, glycolic acid, salicylic acid, citric acid; in particular, the hydrogen bond donor is selected from lactic acid.

3. The transparent composition of claim 1, wherein the hydrogen bond acceptor is selected from the group consisting of quaternary salts including quaternary ammonium salts and quaternary phosphonium salts such as betaine and choline chloride; polyols derived from sugars, such as trehalose, xylitol, glucose and panthenol; and amino acids such as 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 selected from betaine.

4. The transparent composition according to any one of the preceding claims, wherein the deep eutectic solvent is present in an amount of 0.01 to 50 wt%, preferably 0.05 to 35 wt%, or 0.1 to 25 wt%, relative to the total weight of the composition; and/or the weight ratio of hydrogen bond acceptor to hydrogen bond donor is 1:20 to 1:0.1, preferably 1:13 to 1:0.5, or 1:10 to 1:0.8.

5. The transparent composition of any of the preceding claims, wherein the at least one oil is selected from the group consisting of hydrocarbon oils, triglycerides, silicone oils, ether oils, and mixtures thereof; preferably selected from hydrocarbon oils, silicone oils and mixtures thereof; the at least one oil is present in an amount of 10 to 99 wt%, preferably 25 to 97 wt%, or 50 to 95 wt%, relative to the total weight of the composition.

6. The transparent composition according to any one of the preceding claims, wherein the polar phase comprises less than 10wt% water, and in particular less than 6 wt% water, relative to the weight of the deep eutectic solvent.

7. The transparent composition according to any one of the preceding claims, wherein the polar phase comprises from 0.1 to 40 wt%, preferably from 1 to 30 wt%, or from 5 to 25 wt% of a C ₂-C₈ lower polyol or monohydric alcohol, relative to the total weight of the composition, and the polyol is selected from butylene glycol, propylene glycol, pentylene glycol, isopentylene glycol, octylene glycol, glycerol, polyethylene glycol, and mixtures thereof.

8. The transparent composition of any of the preceding claims, further comprising a surfactant combination consisting of at least one nonionic surfactant and optionally at least one anionic surfactant, wherein reverse micelles are formed in the composition.

9. The transparent composition of claim 8, wherein the nonionic surfactant comprises at least one C ₆-C₂₂ alkyl chain, such as one, two or three C ₆-C₂₂ alkyl chains, wherein the alkyl chain in the nonionic surfactant is preferably a C ₁₂-C₂₂ alkyl chain; preferably, the nonionic surfactant further has an HLB value of 0 to 10.

10. The transparent composition of claim 9 wherein the nonionic surfactant is selected from the group consisting of polyglycerol mono-, di-or trioleates containing 2 to 6 glycerol units, polyglycerol mono-, di-or triisostearates containing 2 to 6 glycerol units, and mixtures thereof; preferably selected from the group consisting of polyglycerol-6 dioleate, polyglycerol-2 triisostearate, polyglycerol-2 oleate and mixtures thereof.

11. The transparent composition according to claim 8, wherein the anionic surfactant is selected from mono-or dialkyl sulfosuccinates, preferably from dialkyl sulfosuccinates having two identical alkyl groups, wherein the alkyl groups have from 4 to 24 carbon atoms, preferably from 6 to 18 carbon atoms, particularly preferably from 6 to 14 carbon atoms.

12. The transparent composition of any one of claims 8-11, wherein the surfactant combination consists of:

polyglycerol-2 oleate and polyglycerol-2 triisostearate,

Sodium diethylhexyl sulfosuccinate and polyglycerol-2 oleate,

Sodium diethylhexyl sulfosuccinate and polyglycerol-2-triisostearate, or

Sodium diethylhexyl sulfosuccinate, polyglycerol-2 oleate and polyglycerol-2 triisostearate.

13. The transparent composition according to any one of claims 8-12, wherein the surfactant combination is present in an amount of 0.1 to 20 wt%, preferably 0.5 to 10 wt%, or 1 to 5 wt%, relative to the total weight of the composition; the ionic surfactant is present in an amount of less than 5.0 wt%, preferably less than 3.0 wt%, or less than 1.5 wt%, even from 0.1 wt% to 1.0 wt%, relative to the total weight of the composition.

14. The transparent composition according to any one of claims 8-13, wherein the hydrophilic active ingredient is present in an amount of 0.01 to 5.0 wt%, preferably 0.1 to 2.0 wt%, or 0.2 to 1.0 wt%, relative to the total weight of the composition.

15. The transparent composition according to any one of claims 1-7, which is in the form of a biphasic oily product, such as hair oils, including leave-on hair oils and rinse-off hair oils, preferably leave-on hair oils, wherein at least one oil is present in an amount of from 10 to 90 wt%, preferably from 25 to 80 wt%, or from 40 to 70 wt%, relative to the total weight of the composition; preferably, the deep eutectic solvent comprising a hydrogen bond donor and a hydrogen bond acceptor is present in an amount of 8 wt% to 50 wt%, preferably 12 wt% to 35 wt%, or 15 wt% to 25 wt%, relative to the total weight of the composition.

16. The transparent composition according to any one of claims 8-14, which is in the form of a homogeneous oily product, such as hair oils, including leave-on hair oils and rinse-off hair oils, preferably leave-on hair oils, wherein at least one oil is present in an amount of 80 to 99 wt%, preferably 85 to 98 wt%, or 90 to 96 wt%, relative to the total weight of the composition; preferably, the deep eutectic solvent comprising a hydrogen bond donor and a hydrogen bond acceptor is present in an amount of 0.01 to 5wt%, preferably 0.05 to 3 wt%, or 0.1 to 2 wt%, relative to the total weight of the composition.