W / O EMULSION OF CHITOSAN(S), COMPRISING A LIQUID FATTY PHASE AND AT LEAST ONE NON-IONIC SURFACTANT, ITS PREPARATION METHOD, AND COSMETIC COMPOSITION CONTAINING IT

Abstract

The invention relates to a water-in-oil (W / O) emulsion comprising: - from 0.5 to 20% by weight of one or more chitosans relative to the total weight of the emulsion, and one or more acids with a pKa < 5, solubilized in an aqueous phase with a pH < 6, - one or more non-ionic surfactants, the HLB of said surfactant or of the mixture of said surfactants ranging from 2 to 8, and - a fatty phase that is liquid at room temperature. It also relates to its preparation process and to a cosmetic composition comprising it in the presence of a washing base.

Description

Title of the invention: W / O EMULSION OF CHITOSAN(S), COMPRISING A LIQUID FATTY PHASE AND AT LEAST ONE NON-IONIC SURFACTANT, ITS PREPARATION METHOD, AND COSMETIC COMPOSITION CONTAINING IT

[0001] The present invention relates to a water-in-oil emulsion comprising an aqueous phase based on chitosan(s), a liquid fatty phase, and one or more non-ionic surfactants, the HLB of said non-ionic surfactant or of the mixture of non-ionic surfactants ranging from 2 to 8.

[0002] The invention also relates to a cosmetic composition containing it, as well as a process for preparing such an emulsion.

[0003] The invention further relates to the use of said emulsion for the cosmetic treatment, preferably the cleaning and / or conditioning, of keratin fibers, in particular human keratin fibers such as hair.

[0004] The formulation of environmentally friendly cosmetic products, i.e. those whose design and development take environmental issues into account, is becoming a major concern to help meet global challenges.

[0005] In this context, it is important to develop new cosmetic compositions with a better carbon footprint, in particular by promoting the use of renewable raw materials and / or with a good index of naturalness and / or of natural origin and more particularly of plant origin while reducing the use of compounds of petrochemical origin.

[0006] It is therefore essential to propose more sustainable compositions and / or preparation processes and / or ingredients, thus making it possible to respond to these environmental challenges.

[0007] In the field of cleaning and conditioning keratin fibers, in particular human fibers such as hair, patent application WO 2021 / 013546 describes a water-in-oil emulsion composition which allows improved delivery of a skin-beneficial agent having a solubility in water at 25°C of at least 0.001%. It comprises an aqueous phase comprising the beneficial agent, a hydrophobic phase based on petrolatum or wax, and an emulsifier. The skin-beneficial agent is selected from antimicrobial cationic polymers, soluble vitamins, soluble sunscreens, alpha-hydroxy acids (AHAs), dihydroxyacetone (DHA), caffeine, peptides, hyaluronic acid. Chitosan can be used as an antimicrobial polymeric active.

[0008] The fatty substances used in this document, such as beeswax, rice bran wax, camauba wax, are solid at room temperature, or those such as petrolatum are semi-solid. However, these solid or semi-solid fatty substances have the disadvantage of adding heaviness to the hair, which can lead to an unwanted greasy feel, particularly when they are incorporated into shampoo compositions.

[0009] Furthermore, chitosan is a polysaccharide of interest due to its chemical functionalities and its natural origin. For cosmetic uses, it allows in particular to obtain conditioning effects on the hair fiber, particularly on damaged hair.

[0010] Nevertheless, the incorporation of chitosan into cosmetic compositions containing anionic species remains a challenge. For example, in a shampoo, the presence of anionic surfactants leads to the formation of aggregates by electrostatic interaction with the chitosan. The compositions obtained become inhomogeneous and / or unstable over time, which makes them unusable for cosmetic applications.

[0011] There is therefore a need to provide formulations which make it possible to convey chitosan in cosmetic products, whilst avoiding the formation of aggregates in the presence of anionic species such as surfactants present in washing bases, and which make it possible to obtain better quality of foam (start and / or abundance) and / or speed of drying of the hair.

[0012] The applicant has thus surprisingly discovered that the combination of 0.5 to 20% by weight, preferably 5 to 15% by weight, of at least one chitosan and at least one acid with a pKa < 5, preferably organic, solubilized in an aqueous phase with a pH < 6, of at least one non-ionic surfactant, the HLB of said surfactant or of the mixture of said surfactants ranging from 2 to 8, and of a fatty phase which is liquid at room temperature in a water-in-oil (W / O) emulsion, makes it possible to satisfy this need.

[0013] Thus, the subject of the present invention is a water-in-oil (W / O) emulsion comprising: - from 0.5 to 20% by weight, preferably from 5 to 15% by weight, of one or more chitosans, relative to the total weight of the emulsion, and one or more acids of pKa < 5, preferably organic, solubilized in an aqueous phase of pH < 6, - one or more non-ionic surfactants, the HLB of said non-ionic surfactant or of the mixture of said non-ionic surfactants ranging from 2 to 8, and - a liquid fatty phase at room temperature (25°C).

[0014] The emulsion can be incorporated into cosmetic compositions containing anionic species such as washing bases without causing destabilization of the composition by formation of aggregates.

[0015] The emulsion is homogeneous, i.e. does not present any aggregates. It is stable during storage and in particular does not present any phase shift over time, in particular for 1 month at room temperature.

[0016] Furthermore, the cosmetic compositions comprising said emulsion have improved cosmetic properties such as foam qualities (start and / or abundance), and / or speed of drying of the hair.

[0017] The invention also relates to a cosmetic composition comprising a water-in-oil emulsion according to the invention, and one or more anionic surfactants.

[0018] Another subject of the invention is a process for preparing said emulsion.

[0019] The invention also relates to the use of said emulsion in cosmetics.

[0020] Yet another subject of the invention is a process for the cosmetic treatment of keratin fibers, in particular human fibers, such as hair, comprising the application of said cosmetic composition to said fibers.

[0021] Other objects, characteristics, aspects and advantages of the invention will appear even more clearly on reading the description and the examples which follow.

[0022] In what follows, and unless otherwise indicated, the limits of a domain of values ​​are included in this domain, in particular in the expressions “between” and “ranging from ... to ...”.

[0023] The expression "at least one" used in the present description is equivalent to the expression "one or more".

[0024] The water-in-oil emulsion or W / O emulsion comprises a continuous liquid fatty phase (or oily phase) and an aqueous dispersed phase.

[0025] Aqueous phase The aqueous phase comprises water, one or more chitosans and one or more acids, preferably organic, with a pKa of less than 5. The amount of aqueous phase preferably varies from 50 to 90% by weight, better still from 50 to 80% by weight, and more preferably from 65 to 75% by weight relative to the total weight of the W / O emulsion.

[0026] The W / O emulsion contains a total amount of water preferably ranging from 20 to 80% by weight, better still from 30 to 70% by weight, and more preferably from 40 to 50% by weight relative to the total weight of the W / O emulsion.

[0027] The aqueous phase has a pH of less than 6, preferably ranging from 2 to 6, better still from 3 to 5.

[0028] Chitosan The chitosan(s) are found in the aqueous phase of the W / O emulsion. The chitosan(s) may have a degree of acetylation less than or equal to 40%, preferably less than or equal to 30%, more preferably less than or equal to 15%, better between 1 and 10%. The chitosans used preferably have a molecular weight of less than 200 kDa, preferably between 1000 and 150000 Da.

[0029] The chitosan(s) are present in an amount ranging from 0.5 to 20% by weight, preferably from 5% to 15%, more preferably from 6 to 14% by weight, better still from 7 to 13% by weight, relative to the total weight of the W / O emulsion.

[0030] Acid with pKa < 5 The W / O emulsion according to the present invention comprises one or more acids with a pKa of less than 5.

[0031] This or these acids may be organic or mineral, preferably organic. Examples of mineral acids include hydrochloric acid. Preferably, the acid(s) are organic.

[0032] The acid or acids with a pKa of less than 5 are found in the aqueous phase.

[0033] Preferably, the acid(s) with a pKa of less than 5 are organic. They are preferentially chosen from the carboxylic acids of the following formula (I): in which: A represents a monovalent group when n is 0, or a polyvalent group when n is greater than or equal to 1; A represents a saturated or unsaturated, cyclic or non-cyclic, aromatic or non-aromatic hydrocarbon group, comprising from 1 to 6 carbon atoms, optionally interrupted by one or more heteroatoms such as O or NH, preferably O, and / or substituted by one or more hydroxy groups; preferably A represents a monovalent C1-C6 alkyl or phenyl group, or a polyvalent C1-C6 alkylene or phenylene group optionally substituted by one or more hydroxy groups; n represents an integer ranging from 0 to 10, preferably from 0 to 5, better still from 0 to 2.

[0034] More particularly, the acid or acids with a pKa of less than 5 are chosen from α-hydroxy acids.

[0035] More particularly, the acid(s) with a pKa of less than 5 are chosen from the compounds of formula (I) in which A represents a phenyl group, or a C1-C6, in particular C1-C4, alkylene group, substituted by one or more hydroxyl groups, preferably by a hydroxyl group, or a 6-membered heterocyclic group substituted by several OH groups, one of the members of which denotes an oxygen atom; and n ranges from 0 to 2.

[0036] More particularly, the acid or acids with a pKa of less than 5 is or are chosen from those of formula (I) in which: n=0 and A represents a C1-C6, in particular C1-C4, alkyl group, optionally substituted by an OH group; or n=0 and A represents a phenyl group, or a phenyl group substituted by an OH group or n=0 and A represents a 6-membered heterocyclic group substituted by several OH groups, one of the members of which denotes an oxygen atom; or n = 1 or 2, and A represents a C1-C6, in particular C2-C4, di- or trivalent alkyl group, or a C1-C6, in particular C2-C4, di- or trivalent alkyl group optionally substituted by an OH group.

[0037] Even more preferably, the acid or acids with a pKa of less than 5 is or are chosen from acetic acid, citric acid, glutaric acid, lactic acid, gluconic acid, maleic acid and mixtures thereof, better still from citric acid, lactic acid, and even better still it is lactic acid.

[0038] The W / O emulsion according to the invention comprises a total quantity of the acid(s) with a pKa of less than 5, preferably ranging from 0.5 to 20% by weight relative to its total weight.

[0039] Preferably, the weight ratio between the total quantity of acid(s) with a pKa of less than 5 and the quantity of chitosan(s) ((acid(s) with a pKa of less than 5) / chitosan(s)) ranges from 0.1 to 5, even more preferably from 0.5 to 2.

[0040] Non-ionic surfactants The W / O emulsion according to the present invention comprises one or more non-ionic surfactants, the HLB of said non-ionic surfactant or of the mixture of said non-ionic surfactants ranging from 2 to 8.

[0041] When using a mixture of non-ionic surfactants, the mixture must have an HLB ranging from 2 to 8. The HLB of a mixture of surfactants containing a% of A and b% of B (mass percentage relative to the total weight of the mixture) is then calculated as follows: HLB (A + B) = a% * HLB (A) + b % * HLB (B).

[0042] The term HLB (from the English “Hydrophilic Lipophilic Balance”) is well known to those skilled in the art, and designates the hydrophilic-lipophilic balance of a surfactant at 25°C in the sense of Griffin.

[0043] By hydrophilic-lipophilic balance (HLB) is meant the balance between the size and strength of the hydrophilic group and the size and strength of the lipophilic group of the surfactant. The HLB value according to Griffin is defined in J. Soc. Cosm. Chem. 1954 (volume 5), pages 249-256.

[0044] In particular, it is possible to use non-ionic surfactants having an HLB ranging from 2 to 8 which are cited in the reference work McCutcheons Emulsifiers & Detergents, International Edition of 1998 and following.

[0045] Reference may also be made to the document “Encyclopedia of Chemical Technology, KIRK-OTHMER”, volume 22, p. 333-432, 3rd edition, 1979, WILEY, for the definition of the emulsifying properties and functions of surfactants, in particular p. 347-377 of this reference, for non-ionic surfactants.

[0046] The non-ionic surfactants suitable for the invention may in particular be chosen, alone or in mixtures, from: • C16-C30 fatty alcohols, saturated or unsaturated, linear or branched, oxyalkylenated; • C16-C30 fatty amides, saturated or unsaturated, linear or branched, possibly oxyalkylenated; • esters of C16-C30 fatty acids, saturated or unsaturated, linear or branched, and of poly(ethylene oxide); • esters of C16-C30 fatty acids, saturated or unsaturated, linear or branched, and of sorbitan, possibly polyoxyethylenated; • esters of C10-C30 fatty acids, preferably C10-C24, saturated or unsaturated, linear or branched, or of polymers of these fatty acids, and of glycerol or polyglycerol; • oxyethylenated vegetable oils, saturated or not; • (C16-C30 alkyl)glucosides, preferably (C16-C22 alkyl)glucosides; • ethylene oxide and / or propylene oxide condensates; • oxyethylenated and / or oxypropylenated silicones; and • phospholipids such as lecithins.

[0047] By “oxyalkylenated” is meant compounds which comprise a number of ethylene oxide and / or propylene oxide groups which can range from 1 to 15, preferably from 1 to 10.

[0048] By “polyglycerolated” is meant compounds which comprise a number of glycerol groups which can range from 2 to 10, preferably from 2 to 6.

[0049] The saturated or unsaturated, linear or branched, oxyalkylenated C16-C30, preferably C16-C24 fatty alcohols are in particular oxyethylenated and / or oxypropylenated. They comprise in particular 1 to 10, and more preferably 2 to 5 oxyethylene and / or oxypropylene units.

[0050] As examples of C16-C30 fatty alcohols, saturated or not, linear or branched, oxyalkylenated, we can notably cite ethoxylated cetyl alcohol with 2 oxyethylene units (CTFA name "Ceteth-2"), ethoxylated stearyl alcohol with 2 oxyethylene units (CTFA name "Steareth-2"), steareth 4, beheneth-2 and oleth-2.

[0051] The esters of C16-C30 fatty acids, saturated or not, linear or branched, and of poly(ethylene oxide) may be those having a number of ethylene oxide (EO) units ranging from 2 to 10, and more preferably from 2 to 6. Examples that may be mentioned are diethylene glycol monostearate (2 EO), poly-oxyethylenated monostearate with 5 EO.

[0052] As esters of C16-C30 fatty acids, saturated or not, linear or branched, and of sorbitan optionally polyoxyethylenated, it is possible to use those having a number of ethylene oxide (EO) units ranging from 0 to 10, and more preferably from 0 to 5, for example, sorbitan monostearate, sorbitan monoisostearate, sorbitan tristearate.

[0053] The esters of Cio-C3o fatty acids, preferably Cio-C24, saturated or unsaturated, linear or branched, or of polymers of these fatty acids, and of glycerol or polyglycerol, comprise in particular a number of glycerol units ranging from 1 to 8, better still from 1 to 6.Examples of such esters include tetraglyceryl (or polyglyceryl-4) sebacate, hexaglyceryl monolaurate, glyceryl stearate, glyceryl isostearate, diglyceryl monostearate, diglyceryl distearate, triglyceryl (or polyglyceryl-3) diisostearate, tetraglyceryl (or polyglyceryl-4) diisostearate, tetraglyceryl tristearate, decaglyceryl decastearate, hexaglyceryl tristearate, decaglyceryl pentastearate, polyglyceryl-4 polyhydroxystearate, glyceryl monooleate, triglyceryl (or polyglyceryl-3) polyricinoleate, hexaglyceryl (or polyglyceryl-6) polyricinoleate, glyceryl monobehenate, glyceryl dibehenate and glycerol ester of palmitic and stearic acids.

[0054] Preferably, the non-ionic surfactant(s) according to the invention are chosen from esters of saturated or unsaturated, linear or branched C10-C30 fatty acids, or polymers of these fatty acids, and of glycerol or polyglycerol, esters of saturated or unsaturated, linear or branched C16-C30 fatty acids and of sorbitan, lecithins and mixtures thereof. More preferably, they are chosen from polyglyceryl-4 diisostearate / polyhydroxystearate / sebacate, polyglyceryl-3 or polyglyceryl-6 polyricinoleate, polyglyceryl-3 diisostearate, sorbitan isostearate, and mixtures thereof.

[0055] The total amount of the non-ionic surfactant(s), said non-ionic surfactant or the mixture of said non-ionic surfactants having an HLB ranging from 2 to 8, preferably ranges from 2 to 10% by weight relative to the total weight of the W / O emulsion.

[0056] Liquid fatty phase The liquid fatty phase is preferably contained in an amount ranging from 3 to 35% by weight relative to the total weight of the W / O emulsion.

[0057] For the purposes of the present invention, the term “liquid fatty phase” means a liquid fatty phase at 25°C and under atmospheric pressure (1.013.105 Pa).

[0058] The liquid fatty phase contains one or more fatty substances chosen from alkanes, triglyceride oils of vegetable or synthetic origin, fatty acids, fatty alcohols, fatty esters other than triglyceride oils, fatty ethers, and mixtures thereof.

[0059] For the purposes of the present invention, the term “oil” denotes a liquid compound at 25°C and atmospheric pressure (1.013.105 Pa), immiscible with water.

[0060] By "immiscible" is meant that the mixture of the same quantity of water and oil, after stirring, does not lead to a stable solution comprising only one phase, under the aforementioned temperature and pressure conditions. The observation is made with the naked eye or by means of a phase contrast microscope if necessary, on 100 g of mixture obtained after Rayneri stirring sufficient to cause a vortex to appear within the mixture (for information 200 to 1000 rpm); the resulting mixture being left to stand, in a closed bottle, for 24 hours at room temperature before observation.

[0061] The fatty alcohols, fatty esters, fatty ethers and fatty acids more particularly have at least one hydrocarbon group, linear or branched, saturated or unsaturated, comprising from 6 to 40, better still from 8 to 30 carbon atoms, better still from 10 to 22 carbon atoms, optionally substituted, in particular by one or more hydroxyl groups (in particular 1 to 4). If they are unsaturated, these compounds may comprise one to three carbon-carbon double bonds, conjugated or not.

[0062] The alkanes may be chosen from hydrocarbon oils having from 8 to 16 carbon atoms, and in particular: - branched C10-C16 alkanes such as isoalkanes such as isoalkanes (also called isoparaffins) such as C13-C16 Isoparaffin, isododecane, isodecane, isohexadecane, and for example oils sold under the trade names Isopars or Permetyls, alone or in mixtures, preferably isododecane (also called 2,2,4,4,6-pentamethylheptane), for example marketed by INEOS, more preferably isododecane; - linear alkanes, for example C10-C16, alone or in mixtures, for example such as hexane, decane, undecane, tridecane, isoparaffins such as, or n-dodecane (C12) and n-tetradecane (C14) sold by Sasol respectively under the references PARAFOL 12-97 and PARAFOL 14-97, the undecane-tridecane mixture, the mixtures of n-undecane (Cn) and n-tridecane (Cn) obtained in examples 1 and 2 of application WO 2008 / 155059 from Cognis, and their mixtures as well as the mixtures of n-undecane (Cn) and n-tridecane (Cn) Cetiol Ultimate® from BASF; - cyclic, non-aromatic, C5-Ci2 alkanes.

[0063] The alkanes may also be chosen from hydrocarbon oils chosen from linear or branched compounds, of mineral or synthetic origin such as for example: i) paraffin oil, ii) squalane such as the reference NEOSSANCE SQUALANE marketed by AMYRIS, isoeicosane, iii) mixtures of linear, saturated hydrocarbons, particularly in C14-C30, more particularly in Ci5-C28, such as mixtures whose INCI names are for example the following: C15-C 19 alkane, Ci8-C2i alkane, C2rC28 alkane, such as for example the products Gemseal 40, Gemseal 60, Gemseal 120 marketed by Total, Emogreen L19 marketed by SEPPIC, Emogreen L15 marketed by SEPPIC, Emogreen HP40, marketed by SEPPIC, iv) polybutenes, hydrogenated or not, such as for example products from the Indopol range marketed by the company INEOS Oligomers, products with the INCI name HYDROGENATED POLYISOBUTENE; (v) polyisobutenes, hydrogenated or not, preferably hydrogenated, such as, for example, the non-volatile compounds of the Parléam® range marketed by the company NIPPON OIL FATS, (vi) polydecenes, hydrogenated or not, such as, for example, compounds of the PURESYN® range marketed by the company Exxonmobil), (vii) decene / butene copolymers, butene / isobutene copolymers and (viii) their mixtures.

[0064] The triglyceride oils of vegetable or synthetic origin are preferably triglycerides consisting of esters of fatty acids and glycerol, in particular the fatty acids of which may have chain lengths varying from C7 to C22. These oils may be linear or branched, saturated or unsaturated.Examples include heptanoic or octanoic triglycerides, caprylic / capric acid triglycerides, caprylic / capric / succinic acid triglycerides; vegetable oils such as wheat germ, sunflower, grape seed, sesame, cumin, corn, apricot kernel, castor, shea, avocado, olive, soybean, sweet almond, palm, rapeseed, cotton, hazelnut, macadamia, jojoba, alfalfa, poppy, pumpkin, squash, blackcurrant, evening primrose, millet, barley, quinoa, rye, safflower, candlenut, passionflower, musk rose, peanut, coconut, argan, passionflower, kaya; the liquid fraction of shea butter, and the liquid fraction of cocoa butter; as well as their mixtures.

[0065] The fatty acids that can be used in the invention are preferably C6-40 carboxylic acids, better still C8-30, and even more preferably C10-22. As examples of fatty acids, mention may in particular be made of lauric acid, myristic acid, palmitic acid, stearylic acid, oleic acid, isostearic acid, arachidic acid, and mixtures thereof.

[0066] The fatty alcohols are in particular saturated or unsaturated, linear or branched, and in particular comprise from 10 to 26 carbon atoms. They are preferably mono-alcohols. Advantageously, the C10-C26 alcohols are fatty alcohols, preferably branched or unsaturated when they comprise at least 14 carbon atoms. Preferably, the fatty alcohol comprises from 10 to 24 carbon atoms, and more preferably from 12 to 22 carbon atoms, such as in particular lauryl alcohol, isostearyl alcohol, oleyl alcohol, 2-butyloctanol, 2-undecyl pentadecanol, 2-hexyldecyl alcohol, isocetyl alcohol, octyldodecanol and mixtures thereof.

[0067] Fatty esters other than the triglyceride oils mentioned above have a total number of carbon atoms greater than or equal to 8, more advantageously greater than or equal to 10. They may be chosen from: (i) linear aliphatic esters of formula RC(O)-OR' in which RC(O)-O-represents the carboxylic acid residue containing from 2 to 40 carbon atoms, and R' represents a hydrocarbon chain containing from 1 to 40 carbon atoms, aliphatic hydrocarbon esters of alkylene glycol, in particular ethylene glycol or propylene glycol; the total number of carbon atoms being advantageously at least 10.Examples of such esters include, for example, isoamyl laurate, cetostearyl octanoate, isopropyl myristate, isopropyl palmitate, isopropyl stearate or isostearate, ethyl palmitate, 2-ethylhexyl palmitate, isostearyl isostearate, octyl stearate, isostearyl heptanoate, cetyl octanoate, coco caprylate caprate, tridecyl octanoate, 2-ethylhexyl palmitate, hexyl laurate, neopentanoic acid esters such as isodecyl neopentanoate, isotridecyl neopentanoate, neopentanoate isostearyl, 2-octyldocecyl neopentanoate, isononanoic acid esters such as isononyl isononanoate, isotridecyl isononanoate, octyl isononanoate, oleyl erucate; isocetyl stearate, isodecyl neopentanoate, isostearyl behenate, myristyl myristate; . (ii) esters of fatty acids and alcohols or polyols such as polyglycerol-2 triisostearate; glyceryl triisostearate; glyceryl 2-tridecyl tetradecanoate; propylene glycol dioctanoate, polyethylene glycol diheptanoate, propylene glycol 2-diethylhexanoate, pentaerythrityl tetraisostearate, pentaerythrityl tetrape-largonate; pentaerythrityl 2-tetradecyl tetradecanoate; pentaerythrityl tetraisostearate; pentaerythrityl tetraisononanoate; iii) aromatic esters such as tridecyl trimellitate, C12-C15 alcohol benzoate, benzoic acid 2-phenyl ethyl ester, butyl octyl salicylate; iv) fatty esters of alpha hydroxy acids, polyacids or amino acids such as triisoarachidyl citrate, lauroyl isopropyl sarcosinate, dii-isopropyl sebacate; (v) polyesters obtained by condensation of dimer and / or trimer of unsaturated fatty acid and diol such as those with the INCI name dilinoleic acid / butanediol copolymer, dilinoleic acid / propanediol copolymer; polyesters obtained by condensation of dimer of fatty acid and dimer diol such as dimer dilinoleyl dimer dilinoleate; (vi) carbonates of formula RrO-C(O)-O-R2, with R1 and R2, identical or different, represent a C4 to C12, and preferably C6 to C10, linear or branched alkyl chain; the total number of carbon atoms in the carbonate being advantageously at least 10. The carbonate oils may be dicaprylyl carbonate (or dioctyl carbonate), marketed under the name Cetiol CC® by the company BASF, di(ethyl-2-hexyl)carbonate, marketed under the name TEGOSOFT DEC® by the company Evonik, dipropylheptyl carbonate (Cetiol 4 Ail from BASF), dibutyl carbonate; di-neopentyl carbonate; dipentyl carbonate; di neoheptyl carbonate; di-heptyl carbonate; di-isononyl carbonate; or di-nonyl carbonate; and preferably dioctyl carbonate; vii) and mixtures thereof.

[0068] Among the fatty ethers, oils of formula R3-O-R4 are included in which R3 and R4 independently denote a linear, branched or cyclic C6-C24 alkyl group, preferably a C6-C18 alkyl group, and more preferably a C8-C12 alkyl group. It may be preferable for R3 and R4 to be identical. As a linear alkyl group, mention may be made of a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undodyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, an eicosyl group, a behenyl group, a docosyl group, a tricosyl group and a tetracosyl group.As a branched alkyl group, there may be mentioned a 1,1-dimethylpropyl group, a 3-methylhexyl group, a 5-methylhexyl group, an ethylhexyl group, a 2-ethylhexyl group, a 5-methyloctyl group, a 1-ethylhexyl group, a 1-butylpentyl group, a 2-butyloctyl group, an isotridecyl group, a 2-pentylnonyl group, a 2-hexyldecyl group, an isostearyl group, a 2-heptylundecyl group, a 2-octyldodecyl group, a 1,3-dimethylbutyl group, a 1-(1-methylethyl)-2-methylpropyl group, a 1,1,3,3-tetramethylbutyl group, a 3,5,5-trimethylhexyl group, a 1-(2-methylpropyl)-3-methylbutyl group, a 3,7-dimethyloctyl group, and a 2-(1,3,3-trimethylbutyl)-5,7,7-trimethyloctyl group. As a cyclic alkyl group, there may be mentioned a cy-clohexyl group, a 3-methylcyclohexyl group and a 3,3,5-trimethylcyclohexyl group.

[0069] As examples of fatty ether, mention may be made of caprylyl ether, dilauryl ether, dii-sostearyl ether, dioctyl ether, nonylphenyl ether, dodecyl dimethylbutyl ether, cetyl dimethylbutyl ether, cetyl isobutyl ether and mixtures thereof, better still caprylyl ether, such as the reference CETIOL OE marketed by BASF.

[0070] Preferably, the liquid fatty phase contains one or more fatty substances chosen from liquid alkanes, triglyceride oils of vegetable or synthetic origin, liquid fatty acids, liquid fatty alcohols, liquid fatty esters other than triglyceride oils, liquid fatty ethers and their mixtures, better still from liquid alkanes, triglyceride oils of vegetable or synthetic origin, liquid fatty acids, liquid fatty esters other than triglyceride oils, fatty ethers liquids and mixtures thereof, even better still among mixtures of linear, saturated hydrocarbons, particularly C14-C30, more particularly C15-C28, capric / caprylic / succinic acid triglycerides, sesame oil, oleic acid, oleyl erucate, and dicaprylyl carbonate, and mixtures thereof.

[0071] Liquid fatty substance, such as a liquid alkane, a liquid fatty acid, a liquid fatty alcohol, a liquid fatty ester, a liquid fatty ether, is understood to mean a fatty substance having a melting point less than or equal to 25°C and at atmospheric pressure (1,013.105 Pa).

[0072] The W / O emulsion can be prepared by a method known to those skilled in the art. More particularly, the method for preparing the W / O emulsion of the invention comprises the following steps: (a) preparation of the aqueous phase consisting of mixing in a first container, one or more chitosans with water and one or more acids with a pKa of less than 5, so as to obtain an aqueous phase with a pH of less than 6, (b) preparation of the fatty phase consisting of mixing in a second container separate from the first, one or more fatty substances and a non-ionic surfactant with an HLB ranging from 2 to 8 or several non-ionic surfactants, said mixture of non-ionic surfactants having an HLB ranging from 2 to 8, and (c) adding the mixture obtained in step (a) to the mixture obtained in step (b) with stirring; step (b) and / or (c) possibly comprising a heating step.

[0073] An example of a method consists first of all in solubilizing at least one chitosan in water in the presence of at least one acid with a pKa of less than 5, with stirring at a temperature ranging from 20 to 45°C. A chitosan gel is then obtained.

[0074] In a thermostatically controlled tank and under controlled mechanical stirring, for example using a rotor / stator, at least one fatty substance, preferably at least one oil, and at least one non-ionic surfactant with an HLB ranging from 2 to 8 or a mixture of non-ionic surfactants such that the HLB of said mixture ranges from 2 to 8, are mixed, optionally with the addition of heat, preferably at room temperature (25°C) under stirring, until homogenization.

[0075] The chitosan gel is then introduced into the liquid fatty phase with stirring, optionally with the addition of heat, preferably at room temperature (25°C), preferably for a period of 10 to 20 minutes.

[0076] If heat has been applied during the introduction of the aqueous phase into the fatty phase, stirring is maintained until cooling to room temperature.

[0077] A homogeneous water-in-oil emulsion of variable viscosity is then obtained.

[0078] The invention also relates to a cosmetic composition comprising the W / O emulsion as described above. In addition to the W / O emulsion described above, the com position may comprise one or more surfactants chosen from anionic, cationic, non-ionic amphoteric or zwitterionic surfactants, and mixtures thereof, preferably from anionic, amphoteric or zwitterionic surfactants, and mixtures thereof.

[0079] According to a preferred embodiment, the cosmetic composition comprises the W / O emulsion as described above and one or more anionic surfactants.

[0080] The W / O emulsion according to the invention is preferably contained in an amount ranging from 0.1 to 10% by weight, preferably from 0.1 to 5% by weight, more preferably from 0.5 to 3% by weight relative to the total weight of the cosmetic composition.

[0081] The W / O emulsion according to the invention can be incorporated into cosmetic compositions, in particular compositions containing anionic species, in particular anionic surfactants such as washing bases.

[0082] Anionic surfactant(s) The cosmetic composition may comprise one or more anionic surfactants.

[0083] Anionic surfactant is understood to mean a surfactant comprising only anionic groups as ionic or ionizable groups.

[0084] In the present description, an entity is described as being "anionic" when it has at least one permanent negative charge or when it can be ionized into a negatively charged entity, under the conditions of use of the composition of the invention (medium, pH for example) and not comprising a cationic charge.

[0085] The anionic surfactants can be sulfate, sulfonate and carboxylic (or carboxylate) surfactants. A mixture of these surfactants can of course be used.

[0086] It is understood in this description that: - the carboxylate anionic surfactants comprise at least one carboxylic or carboxylate function (-COOH or -COO-), and may optionally also comprise one or more sulfate and / or sulfonate functions; - the anionic sulfonate surfactants comprise at least one sulfonate function (-SO3H or -SO3), and may optionally further comprise one or more sulfate functions, but do not comprise a carboxylate function; and - anionic sulfate surfactants comprise at least one sulfate function but do not comprise a carboxylate or sulfonate function.

[0087] The carboxylic anionic surfactants that can be used therefore comprise at least one carboxylic or carboxylate function (-COOH or -COO).

[0088] They can be chosen from the following compounds: acylglycinates, acyl-lactylates, acylsarcosinates, acylglutamates; alkyl-D-galactoside-uronic acids, alkyl ethercarboxylic acids, alkyl(C aryl) acids 6 3o)ethercarboxylic acids, alkylamidoethercarboxylic acids; as well as the salts of these compounds; the alkyl and / or acyl groups of these compounds comprising from 6 to 30 carbon atoms, in particular from 12 to 28, even better from 14 to 24, or even from 16 to 22, carbon atoms; the aryl group preferably denoting a phenyl or benzyl group; these compounds may be polyoxyalkylenated, in particular polyoxyethylenated and then preferably comprising from 1 to 50 ethylene oxide units, better still from 2 to 10 ethylene oxide units.

[0089] Monoesters of C6-C24 alkyl and poly- Glycoside polycarboxylic acids such as C6-C24 alkyl polyglycoside citrates, C6-C24 alkyl polyglycoside tartrates and C6-C24 alkyl polyglycoside sulfosuccinates, and their salts.

[0090] Preferably, the carboxylic anionic surfactants are chosen from, alone or as a mixture: - acylglutamates, particularly C6-C24, or even C12-C20, such as stearoylglutamates, and in particular disodium stearoylglutamate; - acylsarcosinates, particularly C6-C24, or even C12-C20, such as lauroylsarcosinates, and in particular sodium lauroylsarcosinate; - acyllactylates, particularly Ci2-C28, or even Ci4-C24, such as behenoyl-lactylates, and in particular sodium behenoyllactylate; - C6-C24 acylglycinates, especially C12-C20; - alkyl(C6-C24)ethercarboxylates, and in particular alkyl(C12-C20)ethercarboxylates; - polyoxyalkylenated alkyl(C6-C24) (amido) ether carboxylic acids, in particular those containing 2 to 50 ethylene oxide groups; in particular in the form of salts of alkali or alkaline earth metals, ammonium, or amino alcohol.

[0091] The anionic sulfonate surfactants that can be used comprise at least one sulfonate function (-SO3H or -SO3-).

[0092] They can be chosen from the following compounds: alkylsulfonates, alkylamidesulfonates, alkylarylsulfonates, alpha-olefinsulfonates, paraffinsulfonates, alkylsulfosuccinates, alkylethersulfosuccinates, alkylamidesulfosuccinates, alkylsulfoacetates, N-acyltaurates, acylisethionates; alkylsulfolaurates; as well as the salts of these compounds; the alkyl groups of these compounds comprising from 6 to 30 carbon atoms, in particular from 12 to 28, even better from 14 to 24, or even from 16 to 22, carbon atoms; the aryl group preferably denoting a phenyl or benzyl group; these compounds may be polyoxyalkylenated, in particular polyoxyethylenated and then preferably comprising from 1 to 50 ethylene oxide units, better still from 2 to 10 ethylene oxide motifs.

[0093] Preferably, the anionic sulfonate surfactants are chosen from, alone or as a mixture: - C6-C24 alkylsulfosuccinates, in particular C12-C20, in particular laurylsulfosuccinates; - C6-C24 alkyl ether sulfosuccinates, in particular C12-C20; - alpha-olefin(C6-C24)-sulfonates, preferably alpha-olefin(Ci2-Ci8)-sulfonates, such as C14_C16 olefin-sulfonates; in particular in the form of salts of alkali or alkaline earth metals, ammonium, or amino alcohol.

[0094] The anionic sulfate surfactants that can be used comprise at least one sulfate function (-OSO3H or -OSO3).

[0095] They can be chosen from the following compounds: alkyl sulfates, alkyl ether sulfates, alkylamido ether sulfates, alkylaryl polyether sulfates, monoglyceride sulfates; as well as the salts of these compounds; the alkyl groups of these compounds comprising from 6 to 30 carbon atoms, in particular from 12 to 28, even better from 14 to 24, or even from 16 to 22, carbon atoms; the aryl group preferably denoting a phenyl or benzyl group; these compounds may be polyoxyalkylenated, in particular polyoxyethylenated and then preferably comprising from 1 to 50 ethylene oxide units, better still from 2 to 10 ethylene oxide units.

[0096] Preferably, the anionic sulfate surfactants are chosen from, alone or as a mixture: - alkyl sulfates, particularly C6-C24, or even C12-C20, - alkyl ether sulfates, in particular C6-C24, or even C12-C20, preferably comprising from 2 to 20 ethylene oxide units; in particular in the form of salts of alkali or alkaline earth metals, ammonium, or amino alcohol.

[0097] When the anionic surfactant is in salt form, said salt may be chosen from alkali metal salts such as the sodium or potassium salt, ammonium salts, amine salts and in particular amino alcohol salts, and alkaline earth metal salts such as the magnesium salt.

[0098] Examples of amino alcohol salts include mono-, di- and triethanolamine salts, mono-, di- or triisopropanolamine salts, 2-amino 2-methyl 1-propanol, 2-amino 2-methyl 1,3-propanediol and tris(hydroxymethyl)amino methane salts.

[0099] Preferably, salts of alkali or alkaline earth metals are used, and in particular sodium or magnesium salts.

[0100] Preferably, the anionic surfactants are chosen from, alone or as a mixture, - C6-C24 alkyl sulfates, especially C12-C20, - C6-C24, in particular C12-C20, alkyl ether sulfates; preferably comprising from 1 to 20 ethylene oxide units, - C6-C24 alkylsulfosuccinates, in particular C12-C20, in particular laurylsulfosuccinates, - C6-C24 acylsarcosinates, especially C12-C20, such as lauroylsarcosinates, - alpha-olefin(C6-C24)-sulfonates, preferably alpha-olefin(Ci2-Ci8)-sulfonates, such as C14_C16 olefin-sulfonates, in particular in the form of salts of alkali or alkaline earth metals, ammonium, or amino alcohol.

[0101] The anionic surfactant(s) are preferably present in the composition in an amount ranging from 1 to 20% by weight, in particular from 5 to 15% by weight, relative to the total weight of the composition.

[0102] Amphoteric or zwitterionic surfactants The cosmetic composition may comprise one or more amphoteric or zwitterionic surfactants.

[0103] In particular, the amphoteric or zwitterionic surfactant(s), preferably non-silicone, may in particular be secondary or tertiary aliphatic amine derivatives, optionally quaternized, in which the aliphatic group is a linear or branched chain comprising from 8 to 22 carbon atoms, said amine derivatives containing at least one anionic group such as, for example, a carboxylate, sulfonate, sulfate, phosphate or phosphonate group.

[0104] Mention may in particular be made of alkyl(C8-C20)betaines, alkyl(C8-C20)sulfobetaines, alkyl(C8-C20)amidoalkyl(C1-C6)betaines, alkyl(C8-C20)amidalkyl(C1-C6)sulfobetaines, and mixtures thereof.

[0105] Among the derivatives of secondary or tertiary aliphatic amines, optionally quaternized, which can be used, as defined above, mention may also be made of the compounds of the following respective structures (II) and (III):

[0106] Ra-CONHCH2CH2-N+(Rb)(Rc)-CH2COO, M+, X (II) formula (II), in which: - Ra represents a C10 to C30 alkyl or alkenyl group derived from an acid RaCOOH, preferably present in hydrolyzed coconut oil, preferably Ra represents a heptyl, nonyl or undecyl group; - Rb represents a beta-hydroxyethyl group; - Rc represents a carboxymethyl group; - M+ represents a cationic counterion derived from an alkali, alkaline earth metal, such as sodium, an ammonium ion or an ion derived from an organic amine; and - X represents an organic or inorganic anionic counterion, such as that chosen from halides, acetates, phosphates, nitrates, alkyl(Ci-C4)sulfates, alkyl(Ci-C4)- or alkyl(Ci-C4)aryl-sulfonates, in particular methylsulfate and ethylsulfate; or else M+ and X are absent;

[0107] Ra'-CONHCH2CH2-N(B)(B') (III) formula (III), in which: - B represents the group -CH2CH2OX'; - B' represents the group -(CH2)ZY', with z = 1 or 2; - X' represents the group -CH2COOH, -CH2-COOZ', -CH2CH2COOH, CH2CH2 -COOZ', or a hydrogen atom; - Y' represents the group -COOH, -COOZ', -CH2CH(OH)SO3H or the group CH2 CH(OH)SO3-Z'; - Z' represents a cationic counterion derived from an alkali or alkaline earth metal, such as sodium, an ammonium ion or an ion derived from an organic amine; - Ra' represents a C10 to C30 alkyl or alkenyl group of an acid Ra'-COOH preferably present in coconut oil or in hydrolyzed linseed oil, preferably Ra' an alkyl group, in particular Cp and its iso form, an unsaturated Cp group.

[0108] These compounds are classified in the CTFA dictionary, 5th edition, 1993, under the names disodium cocoamphodiacetate, disodium lauroamphodiacetate, disodium caprylamphodiacetate, disodium capryloamphodiacetate, disodium cocoampho-dipropionate, disodium lauroamphodipropionate, disodium caprylampho-dipropionate, disodium capryloamphodipropionate, lauroamphodi-propionic acid, cocoamphodipropionic acid.

[0109] As an example, mention may be made of cocoamphodiacetate marketed by the company RHODIA under the trade name MIRANOL® C2M concentrate.

[0110] It is also possible to use compounds of formula (IV): Ra”-NHCH(Y”)-(CH2)nCONH(CH2)nN(Rd)(Re) (IV) formula (IV), in which: - Y” represents the group -COOH, -COOZ”, -CH2-CH(OH)SO3H or the group CH2 CH(OH)SO3-Z”; - Rd and Re, independently of each other, represent a C1 to C4 alkyl or hydroxyalkyl radical; - Z” represents a cationic counterion derived from an alkali or alkaline earth metal, such as sodium, an ammonium ion or an ion derived from an organic amine; - Ra” represents a C10 to C30 alkyl or alkenyl group of an acid Ra”-COOH of preferably present in coconut oil or in hydrolyzed linseed oil; and - n and n', independently of each other, denotes an integer ranging from 1 to 3.

[0111] Among the compounds of formula (IV) we can cite the compound classified in the CTFA dictionary under the name sodium diethylaminopropyl cocoaspartamide and marketed by the company CHIMEX under the name CHIMEXANE HB.

[0112] These compounds can be used alone or in mixtures.

[0113] Among the amphoteric or zwitterionic surfactants mentioned above, advantageously used are alkyl(C8-C20)betaines, such as cocobetaine, alkyl(C8-C20)amidoalkyl(C3-C8)betaines, such as cocamidopropylbetaine, alkyl(C8-C20)amphoacetates, alkyl(C8-C20)amphodiacetates and mixtures thereof; preferably alkyl(C8-C20)betaines, alkyl(C8-C20)amidoalkyl(C3-C8)betaines and mixtures thereof; and better still alkyl(C8-C20)amidoalkyl(C3-C8)betaines and mixtures thereof.

[0114] Preferably, the total amount of the amphoteric or zwitterionic surfactant(s) ranges from 0.1 to 10% by weight, better still from 0.1 to 5% by weight, relative to the total weight of the composition.

[0115] The cosmetic composition according to the invention may further comprise one or more additives chosen from salts, emollients, moisturizers, perfumes, peptizers, vitamins, thickeners, suspending agents, conditioning agents, preservatives, anionic, cationic polymers other than the chitosans used in the W / O emulsion, non-ionic and amphoteric, pigments, colorants, nacres and mixtures thereof.

[0116] A person skilled in the art will take care to choose any additives and their quantity so that they do not harm the properties of the cosmetic composition of the present invention.

[0117] These additives may be present in the composition according to the invention in an amount ranging from 0 to 20% by weight relative to the total weight of the composition.

[0118] The present invention also relates to a process for cosmetic treatment, in particular for cleaning and / or conditioning, keratin fibers, in particular human keratin fibers such as hair, comprising a step of applying to said fibers a cosmetic composition as described above.

[0119] The composition can be applied directly to damp or dry hair, preferably to damp hair.

[0120] The step of applying the composition according to the invention may optionally be followed by a rinsing step. Preferably, the step of applying the composition according to the invention is followed by a rinsing step.

[0121] Furthermore, this step of applying the composition according to the invention may optionally be followed by a drying step.

[0122] The present invention also relates to a use of the composition as described above, for the cosmetic treatment, in particular the cleaning and / or conditioning, of keratin fibers, in particular human keratin fibers such as hair.

[0123] More particularly, the composition according to the invention is used as a hair shampoo,

[0124] The following examples serve to illustrate the invention without, however, being limiting in nature. Examples

[0125] Examples 1 to 6 Preparation of the aqueous phase of the W / O emulsion Two chitosan gels were previously prepared by solubilizing a chitosan in an aqueous solution containing lactic acid. The proportions are indicated in Table 1 below in % by weight of active ingredient relative to the total weight of the gel.

[0126] [Tables 1] Gel 1 2 Chitosan (Kiosmetin P from Kitozyme) 14.3 - Chitosan (Kiosmetin CSG from Kitozyme) - 14.3 Lactic acid 14.3 14.3 Water qsp 100 100

[0127] Chitosan in solution in water and lactic acid was mixed under stirring using a rotor / stator between 20 and 45°C.

[0128] Two gels with a pH between 3.5 and 4 were obtained.

[0129] Preparation of the fatty phase of the W / O emulsion In a thermostatically controlled tank and with controlled mechanical stirring using a rotor / stator, the fatty substance(s) and the non-ionic surfactant(s) indicated in Tables 2 and 3 were mixed at 500 rpm and at room temperature (25°C) until homogenized. A fatty phase was thus obtained.

[0130] Preparation of the W / O emulsion A chitosan gel as prepared above is then introduced into the fatty phase with stirring at 2000 rpm in the rotor / stator for 10 min at room temperature.

[0131] A homogeneous water-in-oil emulsion of variable viscosity is then obtained.

[0132] In Tables 2 and 3 below, all proportions are expressed in % by weight of active material (% MA) relative to the total weight of the W / O emulsion. Example 1 2 3 Sesame oil (Refined CT sesame oil from Etico) 22.5 22.5 22.5 Poly gly cery 1- 3 -polyricinoleate (AKOLINE PGPR from Aarhus-karlshamn) HLB: 3-4 7.5 7.5 - Polyglyceryl-4 diisostearate / po-lyhydroxystearate / sebacate (Isolan GPS from Evonik Goldschmidt) HLB: 5 - - 7.5 Gel 1 from Table 1 70 - - Gel 2 from Table 1 - 70 70 Stability for 1 month at room temperature (25 °C) - Macroscopic appearance Homogeneous fluid cream Homogeneous fluid cream Homogeneous fluid cream Example 4 5 6 Sesame oil (Refined CT sesame oil from Etico) 22.5 - 22.5 Oleyl Erucate (CETIOL J 600 from BASF) - 22.5 - Polyglyceryl-6-polyricinoleate (SY-GLYSTER CRS-75 from Sakamoto Yakuhin) HLB: 3 7.5 - - Polyglyceryl-3-diisostearate (Lameform TGI from BASF) HLB: 3 - 7.5 - Poly gly cery 1- 3 -polyricinoleate HLB: 4 (and) sorbitan isostearate HLB: 4.7 (Arlacel 1690-LQ-(MV) from Croda) 7.5 Gel 2 of Table 1 70 70 70 Stability for 1 month at room temperature (25 °C) -Macroscopic appearance Homogeneous fluid cream Viscous paste homogeneous Homogeneous fluid cream

[0135] The chitosan-based W / O emulsions were visually evaluated according to homogeneity (phase shift) and consistency criteria (more or less thick product, which flows more or less easily) after storage for 1 month at room temperature. The results are indicated above in Tables 2 and 3.

[0136] Examples 7-11 The same preparation method as in Examples 1-6 was applied to prepare W / O emulsions with different oils in Examples 7-11. The emulsions obtained from the ingredients in Tables 4 and 5 were also evaluated in the same way as in Examples 1-6. The proportions given in Tables 4 and 5 are in % by weight of active ingredient relative to the total weight of the W / O emulsion. Example 7 8 Oleyl Erucate (CETIOL J 600 from BASF) 22.5 - Caprylic / Capric / Succinic Tri-glycerides (MIGLYOL 829 from CREMER OLEO) - 22.5 Poly gly cery 1- 3 -polyricinoleate (AKOLINE PGPR from Aarhus-karlshamn) HLB: 3-4 7.5 7.5 Gel 1 of Table 1 70 70 Stability for 1 month at room temperature (25 °C) -Macroscopic appearance Homogeneous fluid cream Homogeneous thick cream

[0138] [Tables5] Example 9 10 11 C15-C19 Alkane & Hydrogenated polyfamesene (EMOGREEN HP40 from SEPPIC) 22.5 - - Dicaprylyl carbonate (CETIOL CC from BASF) - 22.5 - Oleic acid (EDENOR OL 75 MY from EMERY OLEO-CHEMICALS) - - 22.5 Poly gly cery 1- 3 -polyricinoleate (AKOLINE PGPR from Aarhus-karlshamn) HLB: 3-4 7.5 7.5 7.5 Gel 1 from Table 1 70 70 70 Stability for 1 month at room temperature (25 °C) -Macroscopic appearance Homogeneous cream Homogeneous fluid cream Homogeneous fluid cream

[0139] Examples 12-15 The same preparation method as in Examples 1-6 was applied to prepare W / O emulsions with different proportions of aqueous phase in Examples 12-15. The emulsions obtained from the ingredients in Table 6 were also evaluated in the same way as in Examples 1-6. The proportions given in Table 6 are in % by weight of active ingredient relative to the total weight of the W / O emulsion.

[0140] [Tableauxô] Example 12 13 14 15 Oleyl Erucate (CETIOL J 600 from BASF) 35 28 8 3 Poly gly cery 1- 3 -polyric inoie ate (AKOLINE PGPR from Aarhuskarlshamn) HLB: 3-4 5 2 2 2 Gel 1 of Table 1 60 70 90 95 Stability for 1 month at room temperature (25 °C) - Macroscopic appearance Homogeneous fluid cream Homogeneous fluid cream Light creaming Light creaming

[0141] Example 16 Two washing bases A and B were prepared comprising the ingredients below in Tables 7 and 8, respectively, in the proportions expressed in % by weight of active material relative to the total weight of each washing base.

[0142] [Tables?] Washing base A % by weight SODIUM LAURETH SULFATE 9.8 COCAMIDOPROPYL BETAINE 1.2 WATER QS 100 Washing base B % by weight SODIUM C14-16 OLEFIN SULFONATE 10 SODIUM LAUROYL SARCOSINATE 1.52 COCAMIDOPROPYL BETAINE 2.0 WATER QS 100

[0144] 99% by weight of each washing base A or B was then mixed with 1% by weight of the W / O emulsion of example 1, with stirring in the rotor / stator at 1500 rpm for 10 min. Compositions Al and Bl were thus obtained.

[0145] These compositions A1 and B1 were compared respectively to compositions A0 and B0 in which the ingredients of the W / O emulsion were introduced directly and successively, that is to say without separate prior preparation of the W / O emulsion.

[0146] [Tables9] Composition A0 (comparative) Al (invention) Washing base A 99 99 Sesame oil Refined CT sesame oil from Etico 0.225 - Poly gly cery 1- 3 -polyricinoleate AKOLINE PGPR from Aarhus-karlshamn 0.075 - Chitosan Kiosmetine CSG from Kitozyme 0.1 - Lactic acid 0.1 - Water 0.50 - W / O emulsion of example 1 - 1 Visual appearance of the final composition Precipitation in the form of aggregates Dispersion of chitosan in the form of emulsion

[0147] [Tables10] Composition B0 (comparative) B1 (invention) Washing base B 99 99 Sesame oil Refined CT sesame oil from Etico 0.225 - Poly gly cery 1- 3 -polyricinoleate AKOLINE PGPR from Aarhus-karlshamn 0.075 - Chitosan Kiosmetine CSG from Kitozyme 0.1 - Lactic acid 0.1 - Water 0.50 - W / O emulsion of example 1 - 1 Visual appearance of the final composition Precipitation in the form of aggregates Dispersion of chitosan in the form of emulsion

[0148] The visual appearance of the compositions was evaluated macroscopically and microscopically immediately after mixing. The result is shown in Tables 9 and 10.

[0149] Compositions A1 and B1 according to the invention, obtained by incorporating the chitosan-based water-in-oil emulsion into washing bases A and B, have a homogeneous appearance with good dispersion of the chitosan. On the other hand, comparative compositions A0 and B0, obtained by direct incorporation of the same ingredients, do not allow good dispersion of the chitosan which forms aggregates. Example 17

[0150] The following compositions were prepared comprising the washing base A or B of Example 16 and at least one of the W / O emulsions of Examples 2-13. The visual appearance of the compositions was evaluated macroscopically and microscopically immediately after mixing. The result is shown in Tables 11-13. Composition A2 A3 A4 A5 A6 Lavante base A 99 99 99 99 99 E / H emulsion of the ex. 2 1 - - - - E / H emulsion of the ex. 3 - 1 - - - E / H emulsion of the ex. 4 - - 1 - - E / H emulsion of the ex. 5 - - - 1 - E / H emulsion of the ex. 6 - - - - 1 Visual appearance Chitosan dispersion Chitosan dispersion Chitosan dispersion Chitosan dispersion Chitosan dispersion

[0152] [Table2] Composition A7 A8 A9 A10 Launch base A 99 99 99 99 E / H emulsion of the ex. 7 1 - - - E / H emulsion of the ex. 8 - 1 - - E / H emulsion of the ex. 9 - - 1 - E / H emulsion of the ex. 10 - - - 1 Visual aspect Chitosan dispersion Chitosan dispersion Chitosan dispersion Chitosan dispersion Composition Ail Bll A12 A13 Sales base A 99 - 99 99 Sales base B - 99 - - Emulsion E / H of the ex. 11 1 1 - - E / H emulsion of the ex. 12 - - 1 - E / H emulsion of the ex. 13 - - - 1 Visual appearance Chitosan dispersion Chitosan dispersion Chitosan dispersion Chitosan dispersion

Claims

Claims ^Claim 1] Water-in-oil (W / O) emulsion comprising: - from 0.5 to 20% by weight, preferably from 5 to 15% by weight, of one or more chitosans relative to the total weight of the emulsion, and one or more acids with a pKa < 5, solubilized in an aqueous phase with a pH < 6, - one or more non-ionic surfactants, the HLB of said non-ionic surfactant or of the mixture of said non-ionic surfactants ranging from 2 to 8, and - a fatty phase which is liquid at room temperature. ^Claim 2] Water-in-oil emulsion according to claim 1, characterized in that the chitosan(s) has(have) a degree of acetylation less than or equal to 40%, preferably less than or equal to 30%, more preferably less than or equal to 15%, better still between 1 and 10%, and a molecular weight preferably between 5000 and 150000 Da. ^Claim 3] Water-in-oil emulsion according to claim 1 or 2, characterized in that the acid or acids with pKa < 5 are organic,preferably chosen from carboxylic acids of formula: r oi oh*1' in which: A represents a monovalent group when n is 0, or polyvalent when n is greater than or equal to 1; A represents a saturated or unsaturated, cyclic or non-cyclic, aromatic or non-aromatic hydrocarbon group, comprising from 1 to 6 carbon atoms, optionally interrupted by one or more heteroatoms such as O or NH, and / or substituted by one or more hydroxy groups; preferably A represents a monovalent C1-C6 alkyl or phenyl group, or a polyvalent C1-C6 alkylene or phenylene group optionally substituted by one or more hydroxy groups; n represents an integer ranging from 0 to 10, preferably from 0 to 5, better still from 0 to 2; better still from acetic acid, citric acid, glutaric acid, lactic acid, gluconic acid,maleic acid and mixtures thereof. ^Claim 4] Water-in-oil emulsion according to any one of the preceding claims, characterized in that it comprises a total amount of the or, acids with a pKa of less than 5, ranging from 0.5 to 20% by weight relative to its total weight.

5. Water-in-oil emulsion according to any one of the preceding claims, characterized in that the weight ratio between the total quantity of acid(s) with a pKa of less than 5 and the quantity of chitosan(s) ((acid(s) with a pKa of less than 5) / chitosan(s)) ranges from 0.1 to 5, preferably from 0.5 to 2.

6. Water-in-oil emulsion according to any one of the preceding claims, characterized in that the non-ionic surfactant(s) are chosen from: • C16-C30 fatty alcohols, saturated or unsaturated, linear or branched, oxyalkylenated; • C16-C30 fatty amides, saturated or unsaturated, linear or branched, optionally oxyalkylenated; • esters of C16-C30 fatty acids, saturated or unsaturated, linear or branched, and of poly(ethylene oxide); • esters of C16-C30 fatty acids, saturated or unsaturated, linear or branched, and of sorbitan, optionally polyoxyethylenated; • esters of C10-C30 fatty acids, preferably C10-C24, saturated or unsaturated, linear or branched, or of polymers of these fatty acids, of glycerol or of polyglycerol; • oxyethylenated vegetable oils, saturated or unsaturated; • (C16-C30 alkyl)glucosides, preferably (C16-C22 alkyl)glucosides; • condensates of ethylene oxide and / or propylene oxide;• oxyethylenated and / or oxypropylenated silicones; and • phospholipids such as lecithins; preferably among esters of saturated or unsaturated, linear or branched C10-C30 fatty acids, or polymers of these fatty acids, and of glycerol or polyglycerol, esters of saturated or unsaturated, linear or branched C16-C30 fatty acids and of sorbitan, lecithins and mixtures thereof; better still among polyglyceryl-4 diisostearate / polyhydroxystearate / sebacate, polyglyceryl-3 or polyglyceryl-6 polyricinoleate, polyglyceryl-3 diisostearate, sorbitan isostearate, and mixtures thereof.;

7. Water-in-oil emulsion according to any one of the preceding claims, characterized in that the total amount of the non-ionic surfactant(s), the HLB of said non-ionic surfactant or of the mixture of said non-ionic surfactants ranging from 2 to 8, preferably ranging from 2 to 10% by weight relative to the total weight of the W / O emulsion.

8. Water-in-oil emulsion according to any one of the preceding claims, characterized in that the liquid fatty phase is contained in an amount ranging from 3 to 35% by weight relative to the total weight of the W / O emulsion.

9. Water-in-oil emulsion according to any one of the preceding claims, characterized in that the liquid fatty phase comprises one or more fatty substances chosen from alkanes, triglyceride oils of vegetable or synthetic origin, fatty acids, fatty alcohols, fatty esters other than triglyceride oils, fatty ethers, and mixtures thereof, preferably from liquid alkanes, triglyceride oils of vegetable or synthetic origin, liquid fatty acids, liquid fatty alcohols, liquid fatty esters other than triglyceride oils, liquid fatty ethers and mixtures thereof, and more preferably from mixtures of linear, saturated hydrocarbons, particularly C14-C30, more particularly C15-C28, capric / caprylic / succinic acid triglycerides, sesame oil, oleic acid, oleyl erucate, and dicaprylyl carbonate, and mixtures thereof. mixtures.

10. Process for preparing the water-in-oil emulsion according to any one of the preceding claims, comprising the following steps: (a) preparation of the aqueous phase consisting of mixing in a first container, one or more chitosans with water and one or more acids with a pKa of less than 5, so as to obtain an aqueous phase with a pH of less than 6, (b) preparation of the fatty phase consisting of mixing in a second container separate from the first one or more fatty substances and a non-ionic surfactant with an HLB ranging from 2 to 8 or several non-ionic surfactants, said mixture of non-ionic surfactants having an HLB ranging from 2 to 8, and (c) adding the mixture obtained in step (a) to the mixture obtained in step (b) with stirring; step (b) and / or (c) may optionally comprise a heating step.

11. Cosmetic composition comprising the water-in-oil emulsion according to any one of claims 1 to 9, preferably in an amount ranging from 0.1 to 10% by weight, preferably from 0.1 to 5% by weight, per relative to the total weight of the composition.

12. Cosmetic composition according to claim 11, further comprising one or more surfactants chosen from anionic, cationic, non-ionic, amphoteric or zwitterionic surfactants, and mixtures thereof, preferably from anionic, amphoteric or zwitterionic surfactants, and mixtures thereof.

13. Cosmetic composition according to claim 11 or 12, comprising one or more anionic surfactants, preferably chosen from, alone or as a mixture, - C6-C24 alkyl sulfates, in particular C12-C20, - C6-C24 alkyl ether sulfates, in particular C12-C20; preferably comprising from 1 to 20 ethylene oxide units, - C6-C24 alkylsulfosuccinates, in particular C12-C20, in particular laurylsulfosuccinates, - C6-C24 acylsarcosinates, in particular C12-C20, in particular lauroylsarcosinates, - alpha-olefin(C6-C24)sulfonates, preferably alpha-olefin(C12-C18)sulfonates, such as C14_i6 olefinsulfonates, in particular in the form of alkali or alkaline earth metal, ammonium, or amino alcohol salts.

14. Cosmetic composition according to claim 12 or 13, characterized in that the total quantity of anionic surfactant(s) ranges from 1 to 20% by weight, better still from 5 to 15% by weight, relative to the total weight of the composition.

15. Cosmetic composition according to any one of claims 11 to 14, comprising one or more amphoteric or zwitterionic surfactants, preferably chosen from alkyl(C8-C20)betaines, alkyl(C8-C2o)amidoalkyl(C3-C8)betaines and mixtures thereof, better still from alkyl(C8-C2o)amidoalkyl(C3-C8)betaines and mixtures thereof.

16. Cosmetic composition according to any one of claims 12 to 15, characterized in that the total quantity of amphoteric or zwitterionic surfactant(s) ranges from 0.1 to 10% by weight, preferably from 0.1 to 5% by weight, relative to the total weight of the composition.

17. Process for cosmetic treatment, preferably cleaning and / or conditioning, of keratin fibers, better still hair, comprising the application of the cosmetic composition according to any one of claims 11 to 16, to said fibers.

18. Use of the composition according to any one of claims 11 to 16, for the cosmetic treatment, preferably the cleaning and / or conditioning, of keratin fibers, better still of hair.