WO2019245011A1

WO2019245011A1 - Stable acidic composition

Info

Publication number: WO2019245011A1
Application number: PCT/JP2019/024617
Authority: WO
Inventors: Thomas SENGMANY; Yuichi Ikeda; Yukinori Yamada
Original assignee: L'oreal
Priority date: 2018-06-18
Filing date: 2019-06-14
Publication date: 2019-12-26
Also published as: JP7226932B2; JP2019218283A

Abstract

The present invention relates to a composition comprising: (a) at least one hydrophobically modified alkylcellulose; (b) at least one amphiphilic polymer comprising at least one hydrophilic unit and at least one hydrophobic unit; (c) at least one alkyl phosphate; and (d) water, wherein the pH of the composition is less than 7.0, preferably less than 6.0, more preferably less than 5.0, and even more preferably less than 4.0. The composition according to the present invention is stable, and can suitably include a cosmetically active ingredient which is unstable in neutral or alkaline conditions. Thus, the cosmetically active ingredient causes, for example, no decomposition.

Description

DESCRIPTION

STABLE ACIDIC COMPOSITION

TECHNICAL FIELD

The present invention relates to a composition which is acidic and stable, and suitable for cosmetic purposes.

BACKGROUND ART

It has been known that cosmetically active ingredients are introduced into compositions for cosmetic purposes. For stability of such compositions, e.g., uniform appearance over a long period of time, at least one thickener may preferably be added to the compositions.

Some cosmetically active ingredients, such as Vitamin C, tend to reduce activity under neutral or alkaline conditions. Therefore, in order to maintain the activity of the cosmetically active ingredients, it is preferable that the compositions including the cosmetically active

ingredient(s) be kept under acidic conditions.

DISCLOSURE OF INVENTION

However, in acidic conditions, many conventional thickeners tend to lose their thickening properties. Thus, compositions including such thickeners may become unstable in acidic conditions, resulting in, for example, a phase separation of the compositions.

An objective of the present invention is to provide a composition which is stable under acidic conditions, and can suitably include a cosmetically active ingredient which is less active in neutral or alkaline conditions.

The above objective can be achieved by a composition comprising:

(a) at least one hydrophobically modified alkylcellulose;

(b) at least one amphiphilic polymer comprising at least one hydrophilic unit and at least one hydrophobic unit;

(c) at least one alkyl phosphate; and

(d) water,

wherein

the pH of the composition is less than 7.0, preferably less than 6.0, more preferably less than 5.0, and even more preferably less than 4.0.

The (a) hydrophobically modified alkylcellulose may be represented by the following formula (1):

wherein

R¹, R², and R³ are the same or different, and are a hydrogen atom, a lower alkyl group, a - [CH₂CH_2-k(CH₃)_kO]_mH group, or a -CH₂CH(OH)CH₂OC_jH_2j+l group;

n is an integer of 100 to 10,000;

k is an integer of 0 or 1 ;

m is an integer of 1 to 10; and

j is an integer of 6 to 26, preferably 12 to 24, more preferably from 14 to 22, and even more preferably from 16 to 20,

providing that the hydrophobically modified alkylcellulose comprises at least one - CH₂CH(OH)CH₂OC_jH_2j+i group per molecule.

The (a) hydrophobically modified alkylcellulose represented by the above formula (1) may comprise a -CH₂CH(OH)CH₂OC_jH2_j+i group in an amount of 0.1 to 10.0% by weight relative to the total weight of the hydrophobically modified alkylcellulose.

The (a) hydrophobically modified alkylcellulose represented by the above formula (1) may comprise 10.0 to 50.0% by weight of a lower alkyl group, 3.0 to 20.0%_> by weight of a - [CH₂CH_2-k(CH₃)_kO]_mH group, and 0.1 to 10.0% by weight of a -CH₂CH(OH)CH₂OQH_2j+l group, relative to the total weight of the hydrophobically modified alkylcellulose.

The amount of the (a) hydrophobically modified alkylcellulose in the composition according to the present invention may be from 0.01% to 10% by weight, preferably from 0.05% to 5%> by weight, and more preferably from 0.1% to 1% by weight, relative to the total weight of the composition.

The (b) amphiphilic polymer may be made of C_10-30 alkyl (meth)acrylate and at least one of acrylic acid, methacrylic acid, and esters thereof.

The (b) amphiphilic polymer may be crosslinked.

The (b) amphiphilic polymer may be selected from the group consisting of acrylates/C 10-30 alkyl acrylate crosspolymer, acrylates/ethylhexyl acrylate crosspolymer, C8-22 alkyl acrylates/methacrylic acid crosspolymer, potassium acrylates/Cl0-30 alkyl acrylate crosspolymer, sodium acrylates/C 10-30 alkyl acrylate crosspolymer, and mixtures thereof.

The amount of the (b) amphiphilic polymer in the composition according to the present invention may be from 0.01% to 10% by weight, preferably from 0.05% to 5% by weight, and more preferably from 0.1 % to 1% by weight, relative to the total weight of the composition.

The (c) alkyl phosphate may be C_l0-30 alkyl phosphate, preferably selected from the group consisting of cetyl phosphate, stearyl phosphate, cetearyl phosphate, and mixtures thereof.

The amount of the (c) alkyl phosphate in the composition according to the present invention may be from 0.01%₎ to 10% by weight, preferably from 0.05%> to 5% by weight, and more preferably from 0.1% to 1% by weight, relative to the total weight of the composition.

The amount of the (d) water in the composition according to the present invention may be from 30%o to 90% by weight, preferably from 40% to 80% by weight, and more preferably from 50%) to 70%o by weight, relative to the total weight of the composition. The composition according to the present invention may further comprise (e) at least one oil.

The composition according to the present invention may further comprise (f) at least one cosmetically active ingredient selected from the group consisting of Vitamin C and derivatives thereof, salicylic acid and derivatives thereof, alpha-hydroxy acids and mixtures thereof.

The present invention also relates to a cosmetic process comprising the step of applying the composition according to the present invention onto a keratin substance.

BEST MODE FOR CARRYING OUT THE INVENTION

After diligent research, the inventors have discovered that it is possible to provide a composition which is stable under acidic conditions, and can suitably include a cosmetically active ingredient which is less active in neutral or alkaline conditions.

Thus, the composition according to the present invention comprises

(a) at least one hydrophobically modified alkylcellulose,

(b) at least one amphiphilic polymer comprising at least one hydrophilic unit and at least one hydrophobic unit,

(c) at least one alkyl phosphate, and

(d) water

wherein

The composition according to the present invention is stable such that uniform appearance of the composition can be maintained over a long period of time. Thus, no phase separation will be caused over a long period of time in the composition according to the present invention.

The composition according to the present invention can suitably include a cosmetically active ingredient which is less active in neutral or alkaline conditions. The cosmetically active ingredient in the composition according to the present invention can exert its activity as it is because it causes, for example, no decomposition or the like.

If the composition according to the present invention comprises at least one oil, it may be in the form of an emulsion which is stable under acidic conditions.

The composition according to the present invention is acidic and can be highly resistant to microorganisms. Therefore, the composition according to the present invention can have good storageability.

The composition according to the present invention can also provide good texture.

Hereafter, the present invention will be described in a detailed manner.

[Composition]

The composition according to the present invention comprises

(a) at least one hydrophobically modified alkylcellulose, (b) at least one amphiphilic polymer comprising at least one hydrophilic unit and at least one hydrophobic unit,

(c) at least one alkyl phosphate, and

(d) water

wherein

(Hydrophobically Modified Alkylcellulose)

The composition according to the present invention comprises (a) at least one

hydrophobically modified alkylcellulose. A single type of hydrophobically modified alkylcellulose, or two or more different types of hydrophobically modified alkylcelluloses may be used in combination.

The (a) hydrophobically modified allylcellylose used for the present invention may be obtained by introducing one or more long-chain alkyl groups that is/are a hydrophobic group or hydrophobic groups into a cellulose ether derivative.

The (a) hydrophobically modified alkylcellulose may be represented by the following formula

(1):

wherein

R¹, R², and R³ are the same or different, and are a hydrogen atom, a lower alkyl group, a - [CH₂CH_2-k(CH₃)_kO]_mH group, or a -CH₂CH(OH)CH₂OC_jH_2j+i group;

n is an integer of 100 to 10,000;

k is an integer of 0 or 1 ;

m is an integer of 1 to 10; and

It is preferable that at least one of R¹, R², and R³ in the above formula (1) be - CH₂CH(OH)CH₂OC_jH_2j+i group wherein j is an integer as defined above.

Among cellulose ether derivatives which are a base of the (a) hydrophobically modified alkyl cellulose, hydroxypropyl methyl cellulose is suitably selected. Hydroxypropyl methyl cellulose (HPMC) is represented by the above formula (1), wherein R¹, R², and R³ are the same or different, and are a hydrogen atom (-H), a methyl group (-CH₃), or a - [CH₂CH(CH₃)0]_mH group, and HPMC contains at least one -[CH₂CH(CH₃)0]_mH group, where m is an integer of 1 to 10, per molecule. It is preferable that at least one of R¹, R², and R³ in the above formula (1) be -[CH₂CH(CH₃)0]_mH group wherein m is an integer as defined above.

Thus, preferably, the (a) hydrophobically modified alkyl cellulose may be obtained by introducing at least one long-chain alkyl group into HPMC. For example, the (a)

hydrophobically modified alkyl cellulose can be produced by reacting HPMC with the stearyl glycidyl ether represented by the formula below in the presence of alkaline catalyst.

In addition to or in place of stearyl glycidyl ether, cetyl glycidyl ether or decyl glycidyl ether may be used.

It is preferable that C_jH_2j+i in a -CH₂CH(OH)CH₂OC_jH_2j+i group that is a hydrophobic group introduced into the (a) hydrophobically modified alkyl cellulose be a stearyl group (-C₁₈H₃7) since the feeling during use of the composition according to the present invention may be further improved. As a result, the -CH₂CH(OH)CH₂OC_jH_2j+i group is preferably a - CH₂CH(0H)CH₂0-CI₈H₃₇ group.

The (a) hydrophobically modified alkyl cellulose represented by the above formula (1) preferably contains a -CH₂CH(OH)CH₂OC_jH_2j+l group in a content of 0.1 to 10.0% by weight, more preferably 0.1 to 2.0% by weight, and even more preferably 0.1 to 1.0% by weight, relative to the total weight of the hydrophobically modified alkyl cellulose. When the content of C_jH_2j+i in the -CH₂CH(OH)CH₂OC_jH_2j+i group is more than 10.0% by weight in the (a) hydrophobically modified alkyl cellulose, the solubility thereof to water may be low and the dissolved solution may tend to become clouded. Therefore, the composition according to the present invention may not be likely to obtain sufficient viscosity.

The lower alkyl group in the (a) hydrophobically modified alkyl cellulose represented by the above formula (1) is preferably a methyl group or an ethyl group, and more preferably a methyl group.

Since the (a) hydrophobically modified alkyl cellulose represented by the above formula (1) may come to have a good solubility to water, the content of a methyl group is preferably 10.0 to 50.0% by weight, more preferably 21.5 to 30.0% by weight, in the (a) hydrophobically modified alkyl cellulose.

The -[CH₂CH_2-k(CH₃)_kO]_mH group in the (a) hydrophobically modified alkyl cellulose represented by the above formula (1) is a -[CH₂CH₂0]mH group when k is 0, and a - [CH₂CH(CH₃)0]_mH when k is 1. A -[CH₂CH(CH₃)0]mH group when k is 1 is particularly preferable.

From the viewpoint of solubility to water, the (a) hydrophobically modified alkyl cellulose represented by the above formula (1) preferably contains a -[CH₂CH(CH₃)0]_mH group in an amount of 3.0 to 20.0% by weight, and more preferably 7.0 to 11.0% by weight in the (a) hydrophobically modified alkyl cellulose.

The contents of the lower alkyl group, -[CH₂CH_2-k(CH₃)_kO]_mH group, and - CH₂CH(OH)CH₂OC_jH_2j+i group in the (a) hydrophobically modified alkyl cellulose can be determined by a method in accordance with The Japanese Pharmacopoeia, 13th edition, the section for hydroxypropyl methyl cellulose 2208.

One example of the (a) hydrophobically modified alkyl cellulose is preferably SANGELOSE available from Daido Chemical Corporation. As the (a) hydrophobically modified alkyl cellulose, hydroxypropylmethylcellulose stearoxy ether, marketed as SANGELOSE 60L, 60M, 90L or 90M, by Daido Chemical Corporation, is more preferable.

The (a) hydrophobically modified allylcellylose can function as a thickener.

The amount of the (a) hydrophobically modified alkyl cellulose(s) in the composition according to the present invention may be 0.01% by weight or more, preferably 0.05% by weight or more, and more preferably 0.1% by weight or more relative to the total weight of the composition.

On the other hand, the amount of the (a) hydrophobically modified alkyl cellulose(s) in the composition according to the present invention may be 10% by weight or less, preferably 5% by weight or less, and more preferably 1% by weight or less relative to the total weight of the composition.

The amount of the (a) hydrophobically modified alkylcellulose(s) in the composition according to the present invention may be from 0.01% to 10% by weight, preferably from 0.05% to 5% by weight, and more preferably from 0.1% to 1% by weight, relative to the total weight of the composition.

(Amphiphilic Polymer)

The composition according to the present invention comprises (b) at least one amphiphilic polymer comprising at least one hydrophilic unit and at least one hydrophobic unit. A single type of such a polymer, or two or more different types of such polymers may be used in combination.

The hydrophilic unit of the (b) amphiphilic polymer may have at least one carboxylic acid which may be in the form of a salt. The hydrophilic unit may be derived from (meth)acrylic acid or salts thereof.

The hydrophobic unit of the (b) amphiphilic polymer may have a fatty chain including 10 to 30 carbon atoms, preferably 12 to 26 carbon atoms, and more preferably 12 to 22 carbon atoms. The hydrophobic unit may be derived from C10-30 alkyl esters of (meth)acrylic acid. It is preferable that the fatty chain be present in a pendent group or a side chain of the (b) amphiphilic polymer. ft is preferable that the (b) amphiphilic polymer comprising at least one hydrophilic unit and at least one hydrophobic unit be hydrophilic such that it is soluble or dispersible in water or in alcohols, in particular chosen from lower alcohols, glycols, polyols.

For the purposes of the present patent application, the term "hydrophilic" polymer means a (co)polymer that is capable of forming hydrogen bond(s) with water or alcohols, in particular chosen from lower alcohols, glycols, and polyols. In particular, it is preferable that the (b) amphiphilic polymers be capable of forming O-H and/or N-H and/or S-H bonds. The (b) amphiphilic polymer can be obtained by polymerization of monomers essentially consisting of acrylic acid, methacrylic acid, and salts or esters thereof. Thus, the (b) amphiphilic polymer may be referred to as a (meth)acrylic/acrylate polymer.

It is preferable that the (b) amphiphilic polymer, if not crosslinked, not be made or obtained by using any monomer other than acrylic acid, methacrylic acid, and salts or esters thereof.

The salt of (meth)acrylic acid may be in the form of an inorganic salt such as an alkaline metal salt, an alkaline earth metal salt, or an ammonium salt.

The ester of (meth)acrylic acid may be selected from alkyl (meth)acrylates and hydroxylalkyl (meth)acrylates. In one embodiment, the ester of (meth)acrylic acid may be selected from C_l-4 alkyl

(meth)acrylates, C_10-30 alkyl (meth)acrylates, hydroxyl CM alkyl (meth)acrylates, and hydroxyl C_10-30 alkyl (meth)acrylates.

The C_1-4 alkyl ester of (meth)acrylic acid may be selected from the group consisting of methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, and mixtures thereof.

The hydroxyl CM alkyl ester of (meth)acrylic acid may be selected from the group consisting of hydroxymethyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, and mixtures thereof.

The C₁ o-3o alkyl (meth)acrylates may be C_12-26 alkyl (meth)acrylates, and preferably C 12-22 alkyl (meth)acrylates. Examples of (C10-C30) (meth)acrylates include lauryl acrylate, stearyl acrylate, decyl acrylate, isodecyl acrylate, and dodecyl acrylate, and the corresponding methacrylates, lauryl methacrylate, stearyl methacrylate, decyl methacrylate, isodecyl methacrylate, and dodecyl methacrylate. Examples of hydroxyl (C₁o-C3₀) (meth)acrylates include hydroxylauryl acrylate,

hydroxystearyl acrylate, hydroxydecyl acrylate, hydroxylisodecyl acrylate, and

hydroxydodecyl acrylate, and the corresponding methacrylates, hydroxylauryl methacrylate, hydroxystearyl methacrylate, hydroxydecyl methacrylate, hydroxyisodecyl methacrylate, and hydroxydodecyl methacrylate.

It is preferable that the (b) amphiphilic polymer be made of C₁o-3o alkyl (meth)acrylate and at least one of acrylic acid, methacrylic acid, and esters thereof. As the esters of acrylic acid and methacrylic acid, mention may be made of those explained above (except for C_10-30 alkyl (meth)acrylate).

For example, the (b) amphiphilic polymer may preferably be made or obtained by the polymerization of the following monomers (I) and (II).

H₂C=C(R¹)COOR² (I) H₂C=C(R’)COOR³ (II) wherein

R¹ is chosen from H and CH₃, preferably H,

R² is chosen from C_l0-3o alkyl, preferably C_l2-26 alkyl, and more preferably C_l2-22 alkyl, and R³ is chosen from H and C_1-4 alkyl such as methyl.

It may be more preferable that the (b) amphiphilic polymer be made or obtained by the polymerization of the following monomers (G) and (II).

H₂C=CHCOOR² (G)

H₂C=C(R¹)COOR³ (II) wherein

R¹ is chosen from H and CH₃,

R² is chosen from C_l0-30 alkyl, preferably C_12-26 alkyl, and more preferably C_l2-22 alkyl, and R³ is chosen from H and CM alkyl such as methyl.

It is preferable that the (b) amphiphilic polymer be crosslinked.

The (b) amphiphilic polymer may be chosen from polymers formed from a mixture of monomers comprising:

(i) (meth)acrylic acid, preferably acrylic acid;

(ii) the monomer of the above formula (I) in which R¹ denotes H or CH₃, preferably H, and R² denotes an alkyl group having from 10 to 30 carbon atoms, preferably from 12 to 26 carbon atoms, and more preferably from 12 to 22 carbon atoms, and

(iii) a crosslinking agent which is a well-known copolymerizable polyethylenic unsaturated monomer, such as diallyl phthalate, allyl(meth)acrylate, allyl ether of sucrose, allyl ether of pentaerythritol, divinylbenzene, (poly)ethylene glycol dimethacrylate and

methylenebisacrylamide. As the allyl ether, for example, a 2-propenyl group may be mentioned.

Use will more particularly be made, among copolymers of this type, of those composed of 95 to 60% by weight of acrylic acid (hydrophilic unit), 4 to 40% by weight of C_l0-C₃₀ alkyl acrylate (hydrophobic unit) and 0 to 6% by weight of crosslinking polymerizable monomer or else of those composed of 98 to 96% by weight of acrylic acid (hydrophilic unit), 1 to 4% by weight of C_l0-C₃₀ alkyl acrylate (hydrophobic unit) and 0.1 to 0.6% by weight of crosslinking polymerizable monomer, such as those described above.

The (b) amphiphilic polymer may be selected from the group consisting of acrylates/C 10-30 alkyl acrylate crosspolymer, acrylates/ethylhexyl acrylate crosspolymer, C8-22 alkyl acrylates/methacrylic acid crosspolymer, potassium acrylates/C 10-30 alkyl acrylate crosspolymer, sodium acrylates/C 10-30 alkyl acrylate crosspolymer, and mixtures thereof.

Preference is very particularly given according to the present invention, among the said polymers above, to acrylate/ C_l0-C₃₀ alkyl acrylate copolymers (INCI name: Acrylates/ C₁o- C₃₀ Alkyl Acrylate Crosspolymer), such as the products sold by Lubrizol under the trade names Pemulen® TR1, Pemulen® TR2, Pemulen EZ4U, Carbopol® Ultrez 20 Polymer, Carbopol® 1382 and Carbopol® EDT 2020. The (b) amphiphilic polymer can function as a thickener, preferably a hydrophilic thickener.

The amount of the (b) amphiphilic polymer(s) in the composition according to the present invention may be 0.01% by weight or more, preferably 0.05% by weight or more, and more preferably 0.1% by weight or more relative to the total weight of the composition.

On the other hand, the amount of the (b) amphiphilic polymer(s) in the composition according to the present invention may be 10% by weight or less, preferably 5% by weight or less, and more preferably 1% by weight or less relative to the total weight of the composition.

The amount of the (b) amphiphilic polymer(s) in the composition according to the present invention may be from 0.01% to 10% by weight, preferably from 0.05% to 5% by weight, and more preferably from 0.1% to 1% by weight, relative to the total weight of the composition.

(Alkyl Phosphate)

The composition according to the present invention comprises(c) at least one alkyl phosphate. A single type of alkyl phosphate, or two or more different types of alkyl phosphates may be used in combination.

The (c) alkyl phosphate that may be used in the compositions according to the present patent application is preferably chosen from C₁o-C₃₀, preferably C₁₂-C₂₄, and more preferably C₁₆- C₁₈ alkyl phosphates, and mixtures thereof.

The (c) alkyl phosphate may be a mono-alkyl phosphate and/or a di-alkyl phosphate.

The (c) alkyl phosphate may be in the form of a salt. The salt may be in the form of an inorganic salt such as an alkaline metal salt, an alkaline earth metal salt, or an ammonium salt, and a mixture thereof. On the other hand, the salt may be in the form of an organic salt such as an amine salt, e.g., a triethanolamine salt.

The (c) alkyl phosphate, which may be in the form of a salt as explained above, may be chosen from cetyl phosphate, stearyl phosphate, cetearyl phosphate and mixtures thereof. It is preferable that the (c) alkyl phosphate be cetyl phosphate, for example sold under the names Amphisol K (DSM Nutritional Products), Amphisol A (Roche), Arlatone MAP (Uniqema) and Crodafos MCA (Croda).

The (c) alkyl phosphate can function as a surfactant, preferably an anionic surfactant.

The amount of the (c) alkyl phosphate(s) in the composition according to the present invention may be 0.01% by weight or more, preferably 0.05% by weight or more, and more preferably 0.1% by weight or more relative to the total weight of the composition.

On the other hand, the amount of the (c) alkyl phosphate(s) in the composition according to the present invention may be 10% by weight or less, preferably 5% by weight or less, and more preferably 1% by weight or less relative to the total weight of the composition. The amount of the (c) alkyl phosphate(s) in the composition according to the present invention may be from 0.01% to 10% by weight, preferably from 0.05% to 5% by weight, and more preferably from 0.1% to 1% by weight, relative to the total weight of the composition.

(Water)

The composition according to the present invention comprises (d) water.

The (d) water can form an aqueous phase or aqueous phases of the composition according to the present invention.

The amount of the water in the composition according to the present invention may be 30% by weight or more, preferably 40% by weight or more, and more preferably 50% by weight or more, relative to the total weight of the first composition.

The amount of the water in the composition according to the present invention may be 90% by weight or less, preferably 80% by weight or less, and more preferably 70% by weight or less, relative to the total weight of the first composition.

The amount of water in the composition according to the present invention may range from 30% to 90% by weight, preferably from 40% to 80% by weight, and more preferably from 50 to 80% by weight, relative to the total weight of the composition.

(Oil)

The composition according to the present invention may comprise (e) at least one oil. A single type of oil, or two or more different types of oils may be used in combination.

The (e) oil can form an oil phase or oil phases in the composition according to the present invention.

Here,“oil” means a fatty compound or substance which is, typically, in the form of a liquid or a paste at room temperature (25°C) under atmospheric pressure (760 mmHg). As the oils, those generally used in cosmetics can be used alone or in combination thereof. These oils may be volatile or non-volatile.

The oil may be a non-polar oil such as a hydrocarbon oil, a silicone oil, or the like; a polar oil such as a plant or animal oil and an ester oil or an ether oil; or a mixture thereof.

The oil may be selected from the group consisting of oils of plant or animal origin, synthetic oils, silicone oils, hydrocarbon oils and fatty alcohols.

As examples of plant oils, mention may be made of, for example, linseed oil, camellia oil, macadamia nut oil, com 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 animal oils, mention may be made of, for example, squalene and squalane.

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 C₁- C₂₆ aliphatic monoacids or polyacids and of saturated or unsaturated, linear or branched C₁- C₂₆ 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 C₄-C₂2 dicarboxylic or tricarboxylic acids and of C_\-Ci2 alcohols, and esters of monocarboxylic, dicarboxylic, or tricarboxylic acids and of non-sugar C₄-C₂₆ 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 C₆-C₃₀ and preferably C_l2-C₂2 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 chosen especially from the group comprising the esters or mixtures of esters of sugars described previously and of linear or branched, saturated or unsaturated C₆-C₃₀ and preferably C₁₂-C₂₂ 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.

5 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

10 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),

15 pentaerythrityl tetra(2-ethylhexanoate), 2-ethylhexyl succinate, diethyl sebacate, and mixtures thereof.

As examples of artificial triglycerides, mention may be made of, for example, capryl caprylyl glycerides, glyceryl trimyristate, glyceryl tripalmitate, glyceryl trilinolenate, glyceryl

20 trilaurate, glyceryl tricaprate, glyceryl tricaprylate, glyceryl tri(caprate/caprylate), and

glyceryl tri(caprate/ caprylate/linolenate) .

As examples of silicone oils, mention may be made of, for example, linear

organopolysiloxanes such as dimethylpolysiloxane, methylphenylpolysiloxane,

25 methylhydrogenpolysiloxane, and the like; cyclic organopolysiloxanes such as

cyclohexasiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane,

dodecamethylcyclohexasiloxane, and the like; and mixtures thereof.

Preferably, the silicone oil is chosen from liquid polydialkylsiloxanes, especially liquid

30 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

35 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.

40

When they are volatile, the silicones are more particularly chosen from those having a boiling point of between 60°C and 260°C, 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

45 Volatile Silicone® 7207 by Union Carbide or Silbione® 70045 V2 by Rhodia,

decamethylcyclopentasiloxane sold under the name Volatile Silicone® 7158 by Union Carbide, Silbione® 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,

50 such as Silicone Volatile® 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; and

(ii) linear volatile polydialkylsiloxanes containing 2 to 9 silicon atoms and having a viscosity of less than or equal to 5 x 10^-6 m²/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 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°C according to ASTM standard 445 Appendix C.

Non-volatile polydialkylsiloxanes may also be used. These non-volatile silicones are more particularly chosen 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 Silbione^® oils of the 47 and 70 047 series or the Mirasil^® oils sold by Rhodia, for instance the oil 70 047 V 500 000;

the oils of the Mirasil^® series sold by the company Rhodia;

the oils of the 200 series from the company Dow Coming, such as DC200 with a viscosity of 60 000 mm²/s; and

the Viscasil^® 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, mention may be made of polydiarylsiloxanes, especially polydiphenylsiloxanes and polyalkylarylsiloxanes such as phenyl silicone oil.

The phenyl silicone oil may be chosen from the phenyl silicones of the following formula:

in which

R₁ to R₁o, independently of each other, are saturated or unsaturated, linear, cyclic or branched C1-C30 hydrocarbon-based radicals, preferably C₁-C₁₂ hydrocarbon-based radicals, and more preferably C₁-C₆ hydrocarbon-based radicals, in particular methyl, ethyl, propyl, or butyl radicals, and

m, n, p, and q are, independently of each other, integers of 0 to 900 inclusive, preferably 0 to 500 inclusive, and more preferably 0 to 100 inclusive,

with the proviso that the sum n+m+q is other than 0.

Examples that may be mentioned include the products sold under the following names:

the Silbione® oils of the 70 641 series from Rhodia;

the oils of the Rhodorsil® 70 633 and 763 series from Rhodia;

the oil Dow Coming 556 Cosmetic Grade Fluid from Dow Coming;

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.

As the phenyl silicone oil, phenyl trimethicone (R₁ to R₁o are methyl; p, q, and n = 0; m=l in the above formula) is preferable.

The organomodified liquid silicones may especially contain polyethyleneoxy and/or polypfopyleneoxy groups. Mention may thus be made of the silicone KF-6017 proposed by Shin-Etsu, and the oils Silwet® L722 and L77 from the company Union Carbide.

The hydrocarbon oils may be chosen from:

linear or branched, optionally cyclic, C₆-C₁₆ 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 Parleam®, 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.

The term“fatty” in the fatty alcohol means the inclusion of a relatively large number of carbon atoms. Thus, alcohols which have 4 or more, preferably 6 or more, and more preferably 12 or more carbon atoms are encompassed within the scope of fatty alcohols. The fatty alcohol may be saturated or unsaturated. The fatty alcohol may be linear or branched.

The fatty alcohol may have the structure R-OH wherein R is chosen from saturated and unsaturated, linear and branched radicals containing from 4 to 40 carbon atoms, preferably from 6 to 30 carbon atoms, and more preferably from 12 to 20 carbon atoms. In at least one embodiment, R may be chosen from C₁₂-C₂₀ alkyl and C₁₂-C₂₀ alkenyl groups. R may or may not be substituted with at least one hydroxyl group.

As examples of the fatty alcohol, mention may be made of lauryl alcohol, cetyl alcohol, stearyl alcohol, isostearyl alcohol, behenyl alcohol, undecylenyl alcohol, myristyl alcohol, octyldodecanol, hexyldecanol, oleyl alcohol, linoleyl alcohol, palmitoleyl alcohol,

arachidonyl alcohol, erucyl alcohol, and mixtures thereof.

It is preferable that the fatty alcohol be a saturated fatty alcohol.

Thus, the fatty alcohol may be selected from straight or branched, saturated or unsaturated C₆- C30 alcohols, preferably straight or branched, saturated C₆-C₃₀ alcohols, and more preferably straight or branched, saturated C_l2-C₂₀ alcohols.

The term“saturated fatty alcohol” here means an alcohol having a long aliphatic saturated carbon chain. It is preferable that the saturated fatty alcohol be selected from any linear or branched, saturated C₆-C₃₀ fatty alcohols. Among the linear or branched, saturated C₆-C₃₀ fatty alcohols, linear or branched, saturated C₁₂-C₂₀ fatty alcohols may preferably be used.

Any linear or branched, saturated C_l6-C₂₀ fatty alcohols may more preferably be used.

Branched C₁₆-C₂₀ fatty alcohols may even more preferably be used.

As examples of saturated fatty alcohols, mention may be made of lauryl alcohol, cetyl alcohol, stearyl alcohol, isostearyl alcohol, behenyl alcohol, undecylenyl alcohol, myristyl alcohol, octyldodecanol, hexyldecanol, and mixtures thereof. In one embodiment, cetyl alcohol, stearyl alcohol, octyldodecanol, hexyldecanol, or a mixture thereof (e.g., cetearyl alcohol) as well as behenyl alcohol, can be used as a saturated fatty alcohol.

According to at least one embodiment, the fatty alcohol used in the composition according to the present invention is preferably chosen from cetyl alcohol, octyldodecanol, hexyldecanol, and mixtures thereof.

The amount of the (e) oil(s) in the composition used in the present invention may be 0.01% by weight or more, preferably 0.1% by weight or more, more preferably 1% by weight or more, and even more preferably 10% by weight or more, relative to the total weight of the composition.

On the other hand, the amount of the (e) oil(s) in the composition used in the present invention may be 50% by weight or less, preferably 40% by weight or less, more preferably 30% by weight or less, and even more preferably 20% by weight or less, relative to the total weight of the composition.

The amount of the (e) oil(s) in the composition used in the present invention may range from 0.01% to 50% by weight, preferably from 0.1% to 40% by weight, more preferably from 1% to 30% by weight, and even more preferably from 10 to 20% by weight, relative to the total weight of the composition.

(Cosmetically Active Ingredient)

The composition according to the present invention may comprise (f) at least one

cosmetically active ingredient selected from the group consisting of Vitamin C and derivatives thereof, salicylic acid and derivatives thereof, alpha-hydroxy acids and mixtures thereof. A single type of such an ingredient, or two or more different types of such ingredients may be used in combination.

The (f) cosmetically active ingredient is stable, such that it can maintain its activity as it is, in the composition according to the present invention which is acidic.

Vitamin C and derivatives thereof

Vitamin C has a D-configuration or L-configuration, and the L-configuration one is preferably employed. Vitamin C is also referred to as ascorbic acid, and has effects of inhibiting the production of melanin due to the strong reduction effects of ascorbic acid. The derivatives of ascorbic acid may be salts of ascorbic acid, and the salts of ascorbic acid are preferably selected from sodium ascorbate, magnesium ascorbyl phosphate, and sodium ascorbyl phosphate. The derivatives of ascorbic acids may be glycosides of ascorbic acid or esters of ascorbic acid. As an example of glycosides of ascorbic acid, mention may be made of, for example, ascorbyl glucoside. As examples of esters of ascorbic acid, mention may be made of, for example, silyl ascorbate, tocopheryl ascorbate, and alkyl ascorbate. As the alkyl ascorbate, methyl ascorbate or ethyl ascorbate is preferably used. In particular, ascorbyl glucoside is preferable. Ascorbic acid or derivatives thereof can be used alone or in combination with two or more types thereof.

As detailed examples of derivatives of ascorbic acid, mention may be made of, for example, 5,6-di-O-dimethylsilyl ascorbate, which is commercially available as PRO-AA from Exsymol SAM; dl-alpha-tocopheryl-2-l-ascorbyl phosphate which is commercially available as SEPIVITAL EPC from Senju Pharmaceutical Co., Ltd.; sodium ascorbyl phosphate which is commercially available as Stay-C 50 from Roche; ascorbyl glucoside which is commercially available from Hayashibara Biochemical Labs., Inc.; 3-O-ethyl ascorbic acid; and the like.

Salicylic acid and derivatives thereof

Salicylic acid is represented by the following chemical formula:

As salicylic acid derivatives, use may be made of any derivative which may for example be used in a cosmetic and/or dermatological composition, and in particular the salicylic acid compounds of the following formula (I) or a salt of such a derivative:

in which:

R₁ represents hydrogen or a saturated, linear, branched or cyclized aliphatic, alkoxy, ester or ketoxy chain, an unsaturated chain carrying one or more conjugated or unconjugated double bonds, these chains containing from 1 to 22 carbon atoms and being capable of being substituted with at least one substituent chosen from halogen atoms, the trifluoromethyl group, the hydroxyl groups in free form or esterified with an acid having from 1 to 6 carbon atoms and alternatively with a carboxyl functional group, which is free or esterified with a lower alcohol having from 1 to 6 carbon atoms;

R₂ represents a hydroxyl group or an ester functional group of the following formula (II):

where R* represents a saturated aliphatic group or an alkenyl group having from 1 to 18 carbon atoms;

R₃ represents hydrogen or a saturated or unsaturated linear or branched chain having from 2 to 30 carbon atoms, optionally containing one or more substituents. The chain may be chosen in particular from alkyl and alkenyl radicals containing from 2 to 30 carbon atoms, which are optionally substituted. The substituent may be in particular a hydroxyl radical.

When R3 is hydrogen, it is also possible to use salts of the acids of the above formula (I), and in particular salts obtained by salification with a base.

As a base which is capable of salifying the salicylic acid derivatives of the above formula (I), there may be mentioned, without limitation, inorganic bases such as alkali metal hydroxides (sodium and potassium hydroxides) or ammonium hydroxides or better still the organic bases such as primary, secondary, tertiary or cyclic organic amines and more especially amino acids. By way of example of bases, there may be mentioned glycine, lysine, arginine, taurine, histidine, alanine, valine, cysteine, trihydroxymethylaminomethane (TRISTA) and

triethanolamine.

According to a specific embodiment of the present invention, as derivatives of the above formula (I), those where the radical R₁ contains at least 4 carbon atoms are used in the composition of the present invention are preferred. It is for example formed of a saturated linear alkyl or alkoxy radical having from 4 to 11 carbon atoms.

As derivatives of the above formula (I) in which R₁ is formed of a saturated linear alkyl or alkoxy radical having from 4 to 11 carbon atoms, R₂ is a hydroxyl and R₃ is hydrogen, mention may be made for example of 5-n-octanoylsalicylic (CTFA name: Capryloyl Salicylic Acid), 5-n-decanoylsalicylic, 5-n-dodecanoylsalicylic, 5-n-octylsalicylic, 5-n- heptyloxysalicylic, 5-tert-octylsalicylic, 5 -butoxy salicylic, 5-ethoxysalicylic, 5- methoxysalicylic, 5-propoxysalicylic, 5-methylsalicylic, 5-ethylsalicylic and 5-propylsalicylic acids, and mixtures thereof, these acids being generally salified with a base, the compounds described in the document EP-A-570230 may also be used.

When R₁ represents hydrogen and R₂ a hydroxyl group, the derivative of the above formula (I) is a salicylic acid ester. It includes preferably esters of fatty alcohols such as esters of dodecyl, hexadecyl, stearyl, cetyl, myristyl, linoleyl, octyl, oleyl and tridecyl alcohols, or also esters of butyl, propyl and ethyl alcohols or alternatively the esters of polyols such as the esters of propylene glycol, butylene glycol, ethylene glycol or glycerol, or mixtures of these esters. This may include in particular cetyl salicylate, dodecyl salicylate and tridecyl salicylate.

Alpha-hydroxy acids

The term“a-hydroxy acid”, or“AHA”, here means a carboxylic acid which has at least one hydroxyl group on the adjacent (alpha) carbon atom.

The a-hydroxy acid may be selected from, for example glycolic acid, lactic acid, malic acid, citric acid, tartaric acid, mandelic acid and gluconic acid and mixtures thereof.

The amount of the (f) cosmetically active ingredient(s) in the composition used in the present invention may be 0.001% by weight or more, preferably 0.01% by weight or more, and more preferably 0.1% by weight or more, relative to the total weight of the composition.

On the other hand, the amount of the (f) cosmetically active ingredient(s) in the composition used in the present invention may be 10% by weight or less, preferably 5% by weight or less, and more preferably 1% by weight or less, relative to the total weight of the composition. The amount of the (f) cosmetically active ingredient(s) in the composition used in the present invention may range from 0.001% to 10% by weight, preferably from 0.01% to 5% by weight, and more preferably from 0.1% to 1% by weight, relative to the total weight of the

composition. (pH)

The composition according to the present invention is acidic. Therefore, the pH of the composition according to the present invention, in particular the aqueous phase thereof, is less than 7.0, preferably less than 6.0 and more preferably less than 5.0, and even more preferably less than 4.0.

Among the acidifying agents, mention may be made, by way of example, of mineral or organic acids such as hydrochloric acid, ortho-phosphoric acid, sulfuric acid, carboxylic acids such as acetic acid, tartaric acid, citric acid, and lactic acid, and sulfonic acids.

Among the basifying agents, mention may be made, by way of example, of ammonium hydroxide, alkali metal carbonates, alkanolamines such as mono-, di- and triethanolamines and also their derivatives, sodium or potassium hydroxide and compounds of the formula below:

N W - N

\

R c R.

wherein

W denotes an alkyl ene such as propylene optionally substituted by a hydroxyl or a C₁-C₄ alkyl radical, and R_a, R_b, R_c and R_d independently denote a hydrogen atom, an alkyl radical or a C₁- C₄ hydroxyalkyl radical, which may be exemplified by l,3-propanediamine and derivatives thereof.

The acidifying or basifying agent may be used in an amount ranging from 0.001% to 5% by weight, preferably from 0.01% to 3% by weight, and more preferably from 0.1% to 1% by weight, relative to the total weight of the composition according to the present invention.

(Polyol)

The composition according to the present invention may comprise at least one polyol. A single type of polyol may be used, but two or more different types of polyol may be used in combination.

The term“polyol” here means an alcohol having two or more hydroxy groups, and does not encompass a saccharide or a derivative thereof. The derivative of a saccharide includes a sugar alcohol which is obtained by reducing one or more carbonyl groups of a saccharide, as well as a saccharide or a sugar alcohol in which the hydrogen atom or atoms in one or more hydroxy groups thereof has or have been replaced with at least one substituent such as an alkyl group, a hydroxyalkyl group, an alkoxy group, an acylgroup or a carbonyl group.

Polyols used in the present invention are liquid at ambient temperature such as 25 °C under atmospheric pressure (760 mmHg or 105 Pa).

The polyol may be a C_2-24 polyol, preferably a C_2-9 polyol, comprising at least 2 hydroxy groups, and preferably 2 to 5 hydroxy groups.

The polyol may be a natural or synthetic polyol. The polyol may have a linear, branched or cyclic molecular structure.

The polyol may be selected from glycerins and derivatives thereof, and glycols and derivatives thereof. The polyol may be selected from the group consisting of glycerin, diglycerin, polyglycerin, ethyleneglycol, diethyleneglycol, propyleneglycol,

dipropyleneglycol, butyleneglycol, pentyleneglycol, hexyleneglycol, C₆-C₂₄

polyethyleneglycol, 1,3 -propanediol, l,4-butanediol, and l,5-pentanediol.

The amount of the polyol(s) in the composition used in the present invention may be 0.1% by weight or more, preferably 1% by weight or more, and more preferably 10% by weight or more, relative to the total weight of the composition.

On the other hand, the amount of the polyol(s) in the composition used in the present invention may be 40% by weight or less, preferably 35% by weight or less, and more preferably 30% by weight or less, relative to the total weight of the composition. The amount of the polyol(s) in the composition used in the present invention may range from 0.1% to 40% by weight, preferably from 1% to 35% by weight, and more preferably from 10% to 30% by weight, relative to the total weight of the composition.

(Other Optional Ingredients)

The composition according to the present invention may contain one or more monoalcohols which are in the form of a liquid at room temperature (25°C), such as for example linear or branched monoalcohols comprising from 1 to 6 carbon atoms, such as ethanol, propanol, butanol, isopropanol, isobutanol, pentanol, and hexanol.

The amount of the monoalcohol(s) in the composition used in the present invention may be 0.01% by weight or more, preferably 0.1% by weight or more, and more preferably 1% by weight or more, relative to the total weight of the composition.

On the other hand, the amount of the monoalcohol(s) in the composition used in the present invention may be 15% by weight or less, preferably 10% by weight or less, and more preferably 5% by weight or less, relative to the total weight of the composition.

The amount of the monoalcohol(s) in the composition used in the present invention may range from 0.01% to 15% by weight, preferably from 0.1% to 10% by weight, and more preferably from 1% to 5% by weight, relative to the total weight of the composition.

The composition according to the present invention may also include various adjuvants conventionally used in cosmetic compositions, such as anionic, non-ionic, cationic, and amphoteric or zwitterionic polymers, anionic, non-ionic, cationic, and amphoteric surfactants, antioxidants, chelating agents, sequestering agents, fragrances, dispersing agents,

conditioning agents, film-forming agents, preservatives, co-preservatives, and mixtures thereof, except for the ingredients as explained above.

(Preparation)

The composition according to the present invention can be prepared by mixing the essential ingredient(s) as explained above, and optional ingredient(s), if necessary, as explained above.

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

(Form)

The form of the composition according to the present invention is not particularly limited, and may take various forms such as an emulsion (O/W or W/O form), an aqueous gel, an aqueous solution, or the like.

It is preferable that the composition according to the present invention be in the form of an O/W emulsion, if it includes at least one oil, which comprises oil phases dispersed in a continuous aqueous phase. The dispersed oil phases can be oil droplets in the aqueous phase. The O/W architecture or structure, which consists of oil phases dispersed in an aqueous phase, has an external aqueous phase, and therefore if the composition according to the present invention has the O/W architecture or structure, it can provide a pleasant feeling during use because of the feeling of immediate freshness that the aqueous phase can provide.

Also, the composition according to the present invention may preferably be gelled, and therefore, it can exhibit very good stability when, for example, being stored.

The composition according to the present invention may be a cosmetic composition, preferably a skin cosmetic composition, and more preferably a skin-care or skin-make up cosmetic composition.

The composition according to the present invention is stable for a long period of time even at low and high temperatures.

(Cosmetic Process)

The composition according to the present invention can be used for cosmetic treatments of a keratin substance such as skin, scalp, eyelashes, eyebrows, hair, and nails, and mucous membranes such as lips, preferably skin and lips, and more preferably facial skin and lips.

Thus, the present invention also relates to a cosmetic process for a keratin substance, preferably skin and lips, comprising the step of applying the composition according to the present invention onto the keratin substance.

The present invention also relates to a use of a combination of

(a) at least one hydrophobically modified alkylcellulose,

(b) at least one amphiphilic polymer comprising at least one hydrophilic unit and at least one hydrophobic unit, and

(c) at least one alkyl phosphate,

in a composition comprising (d) water wherein the pH of the composition is less than 7.0, preferably less than 6.0, more preferably less than 5.0, and even more preferably less than 4.0, in order to stabilize the composition.

EXAMPLES

The present invention will be described in a more detailed manner by way of examples.

However, these examples should not be construed as limiting the scope of the present invention. The examples below are presented as non-limiting illustrations in the field of the present invention.

[Examples 1-3 and Comparative Examples 1-9]

The compositions according to Examples 1-3 and Comparative Examples 1-9 were prepared by mixing the ingredients shown in Tables 1 -3. The numerical values for the amounts of the ingredients shown in Tables 1-3 are all based on“% by weight” as active raw materials.

Table 3

(Evaluation)

The compositions according to Examples 1-3 and Comparative Examples 1-9 just after the preparation thereof were stored for 1 week in an air-tight container at 60°C. The aspect of each composition was visually observed and evaluated in accordance with the following criteria.

Good: Stable (No phase separation is recognized)

Poor: Small phase separation (a small volume of liquid is released) is recognized.

Very Poor: Unstable (Phase separation is recognized)

The results are shown in Tables 1-3.

As shown in Tables 1-3, the compositions according to Examples 1-3, which are acidic and include a hydrophobically modified alkylcellulose, an amphiphilic polymer comprising at least one hydrophilic unit and at least one hydrophobic unit, an alkyl phosphate, and water, are stable over time.

In comparison with Example 1 , Comparative Examples 1 -4 demonstrate that both a hydrophobically modified alkylcellulose and an amphiphilic polymer comprising at least one hydrophilic unit and at least one hydrophobic unit are necessary for good stability under acidic conditions.

In comparison with Example 2, Comparative Examples 5-8 demonstrate that an alkyl phosphate is necessary for good stability under acidic conditions.

Thus, in view of Examples 1 and 2, as well as Comparative Examples 1-8, it is clear that a combination of a hydrophobically modified alkylcellulose, an amphiphilic polymer comprising at least one hydrophilic unit and at least one hydrophobic unit, and an alkyl phosphate, is necessary for good stability under acidic conditions.

Example 3 and Comparative Example 9 demonstrate that an acrylate polymer with a hydrophobic unit, which, in Example 3, is composed of a fatty chain with C_l0-30 carbon atoms, can provide better stability as compared to an acrylate polymer without the hydrophobic unit, used in Comparative Example 9.

Claims

1. A composition comprising:

(a) at least one hydrophobically modified alkylcellulose;

(c) at least one alkyl phosphate; and

(d) water,

wherein

2. The composition according to Claim 1, wherein the (a) hydrophobically modified alkylcellulose is represented by the following formula (1):

wherein

R¹, R², and R³ are the same or different, and are a hydrogen atom, a lower alkyl group, a -[CH₂CH_2-k(CH₃)_kO]_mH group, or a -CH₂CH(OH)CH₂OC_jH_2j+i group; n is an integer of 100 to 10,000;

k is an integer of 0 or 1 ;

m is an integer of 1 to 10; and

3. The composition according to Claim 2, wherein the (a) hydrophobically modified alkylcellulose represented by the formula (1) comprises a -CH₂CH(OH)CH₂OC_jH_2j+i group in an amount of 0.1 to 10.0% by weight, relative to the total weight of the hydrophobically modified alkylcellulose.

4. The composition according to Claim 2 or 3, wherein the (a) hydrophobically

modified alkylcellulose represented by the formula (1) comprises 10.0 to 50.0% by weight of a lower alkyl group, 3.0 to 20.0% by weight of a -[CH₂CH_2-k(CH₃)_kO]_mH group, and 0.1 to 10.0% by weight of a -CH₂CH(OH)CH₂OCjH_2j+i group, relative to the total weight of the hydrophobically modified alkylcellulose.

5. The composition according to any one of Claims 1 to 4, wherein the amount of the (a) hydrophobically modified alkylcellulose in the composition is from 0.01% to 10% by weight, preferably from 0.05% to 5% by weight, and more preferably from 0.1% to 1% by weight, relative to the total weight of the composition.

6. The composition according to any one of Claims 1 to 5, wherein the (b) amphiphilic polymer is made of C₁o_-30 alkyl (meth)acrylate and at least one of acrylic acid, methacrylic acid, and esters thereof.

7. The composition according to any one of Claims 1 to 6, wherein the (b) amphiphilic polymer is crosslinked.

8. The composition according to any one of Claims 1 to 7, wherein the (b) amphiphilic polymer is selected from the group consisting of acrylates/Cl0-30 alkyl acrylate crosspolymer, acrylates/ethylhexyl acrylate crosspolymer, C8-22 alkyl

acrylates/methacrylic acid crosspolymer, potassium acrylates/C 10-30 alkyl acrylate crosspolymer, sodium acrylates/C 10-30 alkyl acrylate crosspolymer, and mixtures thereof.

9. The composition according to any one of Claims 1 to 8, wherein the amount of the

(b) amphiphilic polymer in the composition is from 0.01% to 10% by weight, preferably from 0.05% to 5% by weight, and more preferably from 0.1% to 1% by weight, relative to the total weight of the composition.

10. The composition according to any one of Claims 1 to 9, wherein the (c) alkyl

phosphate is C_l0-30 alkyl phosphate, preferably selected from the group consisting of cetyl phosphate, stearyl phosphate, cetearyl phosphate, and mixtures thereof.

11. The composition according to any one of Claims 1 to 10, wherein the amount of the

(c) alkyl phosphate in the composition is from 0.01% to 10% by weight, preferably from 0.05% to 5% by weight, and more preferably from 0.1% to 1% by weight, relative to the total weight of the composition.

12. The composition according to any one of Claims 1 to 11 , wherein the amount of the

(d) water in the composition is from 30% to 90% by weight, preferably from 40% to 80% by weight, and more preferably from 50% to 70% by weight, relative to the total weight of the composition.

13. The composition according to any one of Claims 1 to 12, wherein the composition further comprises (e) at least one oil.

14. The composition according to any one of Claims 1 to 13, wherein the composition further comprises (f) at least one cosmetically active ingredient selected from the group consisting of Vitamin C and derivatives thereof, salicylic acid and derivatives thereof, alpha-hydroxy acids and mixtures thereof.

15. A cosmetic process comprising the step of applying the composition according to any one of Claims 1 to 14 onto a keratin substance.