Betainyl lysine ester and use thereof as an agent for conditioning keratin fibres

Abstract

The present invention relates to a betainyl lysine ester, to a surfactant composition comprising same and to the uses thereof as an agent for conditioning keratin fibres. It also relates to a cosmetic composition in the form of an emulsion comprising such a betainyl lysine ester in a physiologically acceptable medium, and to a method for conditioning keratin fibers, comprising the topical application of this cosmetic composition to the keratin fibers.

Description

[0001] Betainyllysine ester and its use as a conditioning agent for keratin fibers

[0002] SUBJECT OF THE INVENTION

[0003] The present invention relates to a betainyllysine ester, a surfactant composition comprising it and their uses as a conditioning agent for keratin fibers. It also relates to a cosmetic composition in the form of an emulsion comprising, in a physiologically acceptable medium, such a betainyllysine ester, as well as a method for conditioning keratin fibers, comprising the topical application to the keratin fibers of this cosmetic composition.

[0004] BACKGROUND OF THE INVENTION

[0005] Cationic surfactants are essential amphiphilic molecules in cosmetic formulations; they are widely used in hair care applications, such as conditioners and 2-in-1 shampoos, thanks to their detangling and lubricating properties. The most widely used cationic surfactants are quaternary ammoniums, such as behentrimonium chloride (BTAC), cetrimonium chloride (CTAC), behentrimonium methosulfate (BTMS), and distearoylethyl dimonium chloride (DSEDC). These petroleum-based or partially petroleum-based cationic surfactants are present in the majority of conditioners and 2-in-1 shampoos worldwide, and even in skin care products where they are used for their moisturizing and smoothing properties.However, these compounds have an irritant profile, an unfavorable toxicological and ecotoxicological profile and their low biodegradability constitutes a serious disadvantage (Kaczerewska, O. et al., J. Hazard. Mater. 392, 122299 (2020); Garcia, MT et al., Chemosphere 154, 155-160 (2016); Cross, J. & Singer, EJ Cationic Surfactants - Analytical and Biological Evaluation, Surfactant Science Series 53. New York, 53, 61-91 (1994)). On the other hand, their manufacturing processes are polluting and can be toxic to the environment because they use toxic alkylation reagents. According to the classification provided by the European Chemicals Agency (ECHA), these products can induce very toxic long-term effects on aquatic species. They also exhibit significant skin and eye toxicity (Kumar, N. & Tyagi, R., Cosmetics 1, 3-13 (2014); Rhein, L., Handbook for Cleaning / Decontamination of Surfaces vol. 1 (Elsevier BV, 2007)).These are proven allergens that can cause skin irritation. Since the surface of the skin or hair fiber is negatively charged, cationic molecules tend to attach strongly to it and are not effectively removed during the rinsing process. Several studies have shown that contact with a high concentration of these products may facilitate the onset of irritant or allergic dermatitis and even skin burns (Scientific Committee on Consumer Products (SCCP). Opinion on Alkyl (Cl 6, Cl 8, C22) trimethylammonium chloride for uses other than as a preservative. Sccp / 0917 / 05 (2006); Halla, N. et al., Molecules 23, 1-41 (2018); Cameron, DM et al., Toxicol. Vitr. 27, 2203-2212 (2013)). Due to their environmental impact and their irritant nature, the use of these cationic surfactants in cosmetics is limited to hair conditioning formulations.

[0006] The development of eco-responsible alternatives to petroleum-based cationic surfactants now appears to be the solution to resolve the negative effects of these cosmetic ingredients on the environment and human health. In addition, the originality of the plant-based raw materials used for their manufacture can lead to new functionalities, thus opening up the field of applications for cationic surfactants in formulation. 100% bio-based molecules are now arriving on the market to meet these expectations, notably with the CosmeGreen® range developed by the company SurfactGreen. These surfactants carry a permanent cationic charge derived from glycine betaine, a 100% plant-based molecule extracted from sugar beet. The use of this natural raw material avoids the use of highly toxic alkylation reagents involved in the synthesis of petroleum-based quaternary ammonium compounds.This new ingredient is very competitive in traditional applications of cationic surfactants in cosmetics, particularly in hair care (WO2021 / 099715). It is presented in the form of a surfactant composition comprising a glycine betaine ester or amide. Although these surfactants are very effective in various applications, there remains a need to develop other cationic surfactants with good stability in acidic environments, low eco-toxicity and a reinforced cationic character giving them good interaction with negatively charged surfaces such as hair.

[0007] In this context, the Applicant has developed a new cationic surfactant satisfying the aforementioned needs. SUMMARY OF THE INVENTION

[0008] The subject of the invention is a betainyllysine ester of formula (I): in which:

[0009] X is an organic or inorganic anion, the radical Ri is a -NH2 or -NH3 group + , the radical R2 is a C12-C24 alkyl or alkenyl group.

[0010] It also relates to a first process for preparing this betainyllysine ester, comprising the following steps:

[0011] (a) esterification of glycine betaine or one of its salts with at least one C4-C8 monoalcohol in the presence of at least one organic or inorganic acid XH, to obtain a glycine betaine ester salt,

[0012] (b) esterification of L-lysine or one of its salts with at least one linear or branched, saturated or unsaturated, C12-C24 monoalcohol R2-OH in the presence of at least one organic or inorganic acid XH, to obtain a lysine fatty ester salt,

[0013] (c) diluting the lysine fatty ester salt with at least one solvent such as a C4-C8 monoalcohol,

[0014] (d) adding to the diluted lysine fatty ester salt at least one organic or inorganic base, so as to obtain a lysine fatty ester,

[0015] (e) aminolysis of the glycine betaine ester salt obtained in step (a) by reaction with the lysine fatty ester obtained in step (d),

[0016] (I) filtration of insoluble matter, then elimination of residual C4-C8 monoalcohol.

[0017] The invention also relates to a second process for preparing this betainyllysine ester, comprising the following steps:

[0018] (a) esterification of glycine betaine or one of its salts with at least one C4-C8 monoalcohol in the presence of at least one organic or inorganic acid XH, then removal of the residual C4-C8 monoalcohol to obtain a glycine betaine ester salt, (b) addition of L-lysine or one of its salts and esterification thereof with at least one linear or branched, saturated or unsaturated, C12-C24 monoalcohol R2-OH, to obtain a reaction mixture comprising a lysine ester salt,

[0019] (c) fluidification of the reaction mixture, by adding a solvent such as a C4-C8 monoalcohol,

[0020] (d) aminolysis of the glycine betaine ester salt by the lysine ester by adding to the fluidized reaction mixture at least one organic or inorganic base,

[0021] (e) filtration of the insoluble materials present in the reaction medium, then elimination of the solvent.

[0022] The invention also relates to a surfactant composition containing:

[0023] - at least one betainyllysine ester of formula (I), preferably in an amount of 35 to 50% by weight,

[0024] - at least one fatty alcohol R2-OH, preferably in an amount of 35 to 50% by weight,

[0025] - a lysine ester of formula (II): H2N-(CH2)4-CH(NH2)-COOR2 (II), where R2 is a linear or branched, saturated or unsaturated, C12-C24 monoalcohol residue R2-OH, preferably in an amount of 5 to 10% by weight,

[0026] - glycine betaine, preferably in an amount of 3 to 10% by weight,

[0027] - other by-products, chosen from L-lysine, a fatty alcohol ether R2-O-R2, an alkyl chloride CI-R2, a glycine betaine ester salt of formula (III): (CH3)3-N +-CH2-COORI, where Ri is a C4-C8 monoalcohol residue, an acid XH and their mixtures, preferably in a total quantity of 0.5 to 5% by weight, these compounds being found for at least some in salified form by a base X' and the above percentages being related to the total weight of the surfactant composition.

[0028] Another subject of the invention relates to a cosmetic composition in the form of an emulsion comprising, in a physiologically acceptable medium, the aforementioned betainyllysine ester, as well as a cosmetic process for conditioning keratin fibers, comprising the topical application to keratin fibers, such as the hair, beard and / or eyebrows, of this cosmetic composition.

[0029] Finally, the invention relates to the use as a conditioning agent for keratin fibers of this betainyllysine ester or of the aforementioned surfactant composition. FIGURES

[0030] Figure 1 is a scheme for the synthesis of the betainyllysine ester according to the invention using a first method.

[0031] Figure 2 is a scheme for the synthesis of the betainyllysine ester according to the invention using a second method.

[0032] Figure 3 illustrates the hydrolysis reaction of the betainyllysine ester according to the invention in an acidic medium.

[0033] Figures 4, 5 and 6 illustrate the stability (change in percentage over time) of the betainyllysine ester according to the invention, as a function of time and at different temperatures (respectively, 20°C, 40°C, 50°C), in an acidic medium.

[0034] Figure 7 illustrates the percentage decrease in combing force after application of a conditioner comprising a betainyllysine ester according to the invention, after storage for one month at different temperatures (20°C, 40°C, 50°C), in an acidic medium.

[0035] DETAILED DESCRIPTION

[0036] The present invention relates to a novel surfactant, which is a betainyllysine ester of formula (I):

[0037] It was observed that the lysine spacer between glycine betaine (GB) and fatty alcohol (FA) allowed to:

[0038] - facilitate the creation of the link between the cationic polar head GB and the lipophilic chain AG via the establishment of an amide bond with glycine betaine and an ester bond with the fatty alcohol;

[0039] - stabilize the surfactant against hydrolysis via the creation of an amide bond with glycine betaine;

[0040] - ensure high biodegradability and reduced eco-toxicity compared to glycine betaine amides derived from fatty amines; - strengthen the cationic character of surfactants via the presence of the ammonium function of lysine not involved in the bond with glycine betaine, in order to increase electrostatic interactions with negatively charged substrates, such as the hair surface;

[0041] - make it possible to modulate the number of cationic charges (1 or 2) according to the pH value of the medium, the alpha nitrogen function of the ester appearing in the form of a non-ionic amine RI=NH2 (only 1 cationic charge provided by GB) or a cationic ammonium Ri=NHs + (2 cationic charges provided by GB and ammonium).

[0042] Preparation processes

[0043] The betainyllysine ester according to the invention can be prepared from glycine betaine (or trimethylglycine) and L-lysine, or one of their salts, according to a process making it possible to esterify glycine betaine and lysine into corresponding esters, then to carry out an aminolysis reaction between the two esters formed in the presence of a base.

[0044] In a first embodiment, an example of which is illustrated in Figure 1, the two esterification reactions of glycine betaine with a short-chain alcohol and of lysine with a fatty alcohol are carried out separately, then the products of these reactions are mixed in the presence of a base in order to carry out the aminolysis reaction.

[0045] In this embodiment, glycine betaine or one of its salts is esterified, generally with 2 to 5 equivalents, preferably 2.5 to 4 equivalents, more preferably 3 equivalents, of linear or branched C4-C8 monoalcohol. Examples of such alcohols include butanol, pentanol, 3-methylbutan-1-ol (or isoamyl alcohol), fusel alcohol (mixture of pentanol, 2-methylbutan-1-ol and 3-methylbutan-1-ol), hexanol, heptanol, octanol and mixtures thereof. By "butanol" is meant in this description "-butanol, isobutanol and sc -butanol. Butanol, and more particularly "-butanol, as well as hexanol, are preferred for use in this invention, hexanol being particularly preferred. This reaction generally takes place in the absence of any solvent, the alcohol used constituting both the reactant and the medium.This esterification is carried out in the presence of 1.01 to 1.5 equivalents, preferably 1.05 to 1.2 equivalents, of organic or inorganic acid XH. The acid may in particular be chosen from inorganic acids such as hydrochloric acid, sulfuric acid, perhalohydric acids, such as perchloric acid, and mixtures thereof. Alternatively, it may be chosen from organic acids, such as alkyl sulfuric acids, for example decyl or lauryl sulfuric acid; arylsulfonic acids, such as benzenesulfonic acid, paratoluenesulfonic acid; alkylsulfonic acids, such as triflic acid, methanesulfonic acid, ethanesulfonic acid, decylsulfonic acid, laurylsulfonic acid or camphorsulfonic acid; sulfosuccinic acid; and mixtures thereof. Lewis acids can also be used.Preferably, it is an alkylsulfonic acid and in particular ethanesulfonic acid, since it is readily biodegradable, or methanesulfonic acid. The esterification reaction is advantageously carried out at a temperature of between 110 and 180°C, preferably 150 and 170°C, under a pressure of 600 to 150 mbar. The esterification reaction is generally carried out in the absence of solvent. After 5 to 12 hours of reaction (preferably 6 to 8 hours), a conversion of 95% of the glycine betaine or its salt into its ester in the salt form is generally achieved.

[0046] For the preparation of the lysine fatty ester salt, either L-lysine or a salt thereof is used, which may optionally have been previously decolorized, for example using activated carbon. L-lysine hydrochloride is preferably used. L-lysine or its salt 3 is reacted with a linear or branched, saturated or unsaturated, C12-C24 fatty alcohol R2-OH, advantageously in an amount of 0.9 to 4 equivalents, preferably 1 to 3 equivalents and more preferably 1.5 to 2.5 equivalents.Examples of fatty alcohols may be selected from the group consisting of: lauryl alcohol (C12:0), myristyl alcohol (C14:0), cetyl alcohol (C16:0), palmitoleyl alcohol (C16:1), stearyl alcohol (C18:0), oleyl alcohol (C18:1), linoleyl alcohol (C18:2), linolenic alcohol (C18:3), arachidic alcohol (C20:0), arachidonic alcohol (C20:4), behenyl alcohol (C22:0), 2-hexyldecanol (C16R:0), 2-octyldodecanol (C20R:0), 2-decyltetradecanol (C24:0) and mixtures thereof. Suitable fatty alcohol mixtures may be produced from one or more vegetable oils, including soybean, olive, sunflower, corn, palm, coconut, cottonseed, linseed, wheat germ, safflower, or rapeseed oil, for example. Stearic alcohol (or octadecanol) is preferred for use in the present invention.The esterification reaction is carried out in the presence of at least one organic or inorganic acid XH such as those mentioned above, which can be used in an amount of 1.8 to 2.5 equivalents, preferably 1.9 to 2.3 equivalents and more preferably 2.0 to 2.2 equivalents. The esterification reaction is advantageously carried out at a temperature of between 130 and 160°C, preferably 140 to 160°C, under reduced pressure. After 3 to 16 hours of reaction (preferably 6 to 10 hours), a conversion of 94% of L-lysine or its salt into its ester salt is generally achieved.

[0047] After cooling, the mixture containing the lysine ester salt is then diluted with a short-chain (C4-Cs) monoalcohol, such as those mentioned above, and the medium is heated to a temperature generally between 50 and 130°C, preferably between 60 and 110°C and more preferably between 60 and 90°C. An organic or inorganic base is added to the medium, which may in particular be chosen from: sodium carbonate, potassium carbonate, sodium tert-butoxide, potassium tert-butoxide, sodium ethanolate and sodium hydroxide, preferably sodium carbonate. It typically represents from 2 to 5 equivalents, preferably from 2 to 4 equivalents and more preferably from 2.5 to 3.5 equivalents, relative to the amount of lysine ester salt. Sodium carbonate is preferred for use in the present invention.After 1 to 3 hours of neutralization of the two ammonium charges of the lysine ester, the aminolysis of the glycine betaine ester salt is carried out. To do this, the previously prepared glycine betaine ester salt solution is added to the lysine ester reaction medium, generally in an amount of 1.5 to 3 equivalents, preferably 1.7 to 2.3 equivalents. The reaction is carried out at a temperature between 50 and 130°C, preferably between 60 and 110°C and more preferably between 60 and 90°C, for a period of between 12 and 24 hours, preferably 15 to 20 hours, for example 16 to 18 hours. After a step of filtration of insoluble matter (salts) under heat, the short-chain monoalcohol is removed by distillation, under pressure and temperature conditions which depend on the nature of the monoalcohol.

[0048] In another embodiment, the two esterification reactions of glycine betaine and lysine are carried out in cascade mode in the same pot, without isolating any reaction intermediate, i.e. by carrying out a first esterification reaction of glycine betaine or its salt with a short-chain alcohol in the presence of an excess of acid, by removing the residual alcohol by distillation, by carrying out a second esterification reaction between lysine and the fatty alcohol after adding these two reagents in the same pot and without adding any additional acid, and finally by carrying out the aminolysis reaction between the two esters formed after adding a base.

[0049] This synthetic route, an example of which is illustrated in Figure 2, comprises a first step of esterification of glycine betaine or one of its salts, preferably in an amount of 1 to 3 equivalents, more preferably 1.5 to 2.5 equivalents, with a short-chain monoalcohol (C4-Cs) which may be chosen from those mentioned above. The esterification is carried out in the presence of an organic or inorganic acid XH, which may also be chosen from those mentioned above. The latter is generally used in an amount representing 4.01 to 4.5 equivalents, preferably 4.1 to 4.3 equivalents, sufficient to carry out the two esterification reactions of glycine betaine and lysine and neutralize the carboxylate and ammonium functions of lysine and glycine betaine.The presence of an excess of acid to carry out the esterification of glycine betaine has the effect of significantly reducing the reaction time for this first step (from 7 h to 1.5 h). After removal of the residual monoalcohol under reduced pressure, a C12-C24 fatty alcohol R2-OH, advantageously in an amount of 1 to 3 equivalents, preferably 1.2 to 2 equivalents and more preferably 1.4 to 1.6 equivalents, and 1 equivalent of lysine or one of its salts are added to the reaction medium, so as to carry out the second esterification reaction between these two substrates.After a reaction time which generally ranges from 12 to 24 h (preferably from 15 to 20 h) at a temperature generally between 120 and 160°C, preferably from 135 to 155°C, the temperature is lowered, for example to 90-120°C, before adding a solvent consisting of a short C4-C8 monoalcohol to the reaction medium, in an amount ranging for example from 2 to 10 equivalents, preferably from 3 to 7 equivalents and more preferably from 4 to 6 equivalents, in order to fluidify the reaction medium. An organic or inorganic base is then added to this medium, in an amount which usually ranges from 2 to 5 equivalents, and which can be chosen from those mentioned above, in order to carry out the aminolysis reaction. This strategy makes it possible to minimize the presence of residual fatty alcohol in the final composition. After a hot filtration step of insoluble matter (salts), the short-chain monoalcohols are removed by distillation.

[0050] Surfactant composition

[0051] The processes described above lead to a surfactant composition which constitutes another object of this invention and which contains:

[0052] - at least one betainyllysine ester of formula (I), preferably in an amount of 35 to 50% by weight,

[0053] - at least one fatty alcohol R2-OH, preferably in an amount of 35 to 50% by weight,

[0054] - a lysine ester of formula (II): H2N-(CH2)4-CH(NH2)-COOR2 (II), where R2 is a linear or branched, saturated or unsaturated, C12-C24 monoalcohol residue R2-OH, preferably in an amount of 5 to 10% by weight, - glycine betaine, preferably in an amount of 3 to 10% by weight,

[0055] - other by-products, chosen from L-lysine, a fatty alcohol ether R2-O-R2, an alkyl chloride CI-R2, a glycine betaine ester salt of formula (III): (CH3)3-N +-CH2-COORI, where Ri is a C4-C8 monoalcohol residue, an acid XH and their mixtures, preferably in a total quantity of 0.5 to 5% by weight, these compounds being found for at least some in salified form by a base X' and the above percentages being related to the total weight of the surfactant composition.

[0056] Preferably, the radical R2 is chosen from the groups lauryl (C12:0), myristyl (C14:0), cetyl (C16:0), palmitoleyl (C16:1), stearyl (C18:0), oleyl (C18:1), linoleyl (C18:2), linolenyl (C18:3), arachidyl (C20:0), arachidonyl (C20:4), behenyl (C22:0), 2-hexyldecyl (C16R:0), 2-octyldodecyl (C20R:0) and 2-decyltetradecyl (C24R:0).

[0057] Preferably, flag X is chosen from a chloride, a sulfate, a perchlorate, an alkyl sulfate ion, in particular decyl sulfate or lauryl sulfate, an arylsulfonate ion, in particular benzene sulfonate, paratoluene sulfonate, an alkylsulfonate ion, in particular triflate, methanesulfonate, ethanesulfonate, decylsulfonate, laurylsulfonate, camphorsulfonate, or a sulfosuccinate ion, preferably from alkylsulfonates and arylsulfonates, more particularly from methanesulfonate, triflate, paratoluenesulfonate and camphorsulfonate ions, better still, X is the methanesulfonate or ethanesulfonate ion.

[0058] This surfactant composition can be used as such as a hair conditioning agent. Alternatively, it can be subjected to a purification process, for example on a chromatographic column (eluents: dichloromethane / methanol from 100 / 0 to 80 / 20, for example), in order to increase the proportion of betainyllysine ester it contains, or to obtain a 95% or even 100% pure betainyllysine ester.

[0059] Cosmetic compositions

[0060] The betainyllysine ester according to the invention (or the surfactant composition described above) can be used in a cosmetic composition in the form of an emulsion. This emulsion can have a liquid or semi-liquid consistency, a soft consistency of the cream or balm type or a solid consistency. It can be of the oil-in-water (O / W), oil-in-glycerin, water-in-oil (W / O), glycerin-in-oil or multiple (for example W / O / W) type. This emulsion is preferably of the oil-in-water type. It generally contains from 1 to 8% by weight, and preferably from 1 to 4% by weight, of betainyllysine derivative used according to the invention.

[0061] This cosmetic composition may in particular be packaged in a tube, a pump bottle or a jar. Alternatively, it may be packaged in an aerosol container, in order to ensure application of the composition in vaporized form. In the latter case, the cosmetic composition preferably comprises at least one propellant. According to yet another possibility, this composition may take the form of a bar or stick.

[0062] The cosmetic composition according to the invention comprises a physiologically acceptable medium, that is to say a medium compatible with the keratin fibers and the skin, in particular with the hair and the scalp, preferably cosmetically acceptable, that is to say which does not generate irritation or redness of the skin or the scalp or any other undesirable effect after application to the keratin fibers.

[0063] This cosmetic composition comprises an aqueous phase comprising water and / or one or more water-soluble solvents chosen from C1-C4 alcohols, such as ethanol, isopropanol, tert-butanol or α-butanol, polyols such as glycerol, propylene glycol and polyethylene glycols, and mixtures thereof. Preferably, the cosmetic composition has a total water content of between 5 and 95% by weight, preferably between 10 and 90%, for example between 40 and 85% by weight, in particular between 50 and 80% by weight relative to the total weight of the composition. The pH of this composition generally varies from 3 to 9, preferably from 3.5 to 7, preferentially from 4 to 6.5.It can be adjusted within this range using at least one pH adjuster, chosen for example from: sodium or calcium gluconate, sodium lactate, sodium glycinate, sodium citrate and the buffer solutions lactic acid / sodium lactate, acetic acid / sodium acetate and gluconic acid / sodium gluconate.

[0064] It further comprises at least one fatty phase containing at least one fatty substance, so as to form an emulsion. Preferably, the fatty substance(s) are chosen from oils, pasty fatty substances, waxes and their mixtures. By "oils" is meant a compound that is liquid at room temperature (25°C) and atmospheric pressure (10 5Pa) which, when introduced at a rate of at least 1% by weight into water at 25°C, is not at all soluble in water, or soluble to a level of less than 10% by weight, relative to the weight of oil introduced into the water. By "pasty fats" is meant fats with a reversible liquid / solid state change, having an anisotropic crystalline organization in the solid state and comprising at a temperature of 23°C a liquid fraction and a solid fraction, such as vegetable butters. The term "wax" designates, in the context of this description, a fat which is solid at 25°C, with a reversible solid / liquid state change, having a melting point generally between 30 and 160°C, preferably between 50 and 90°C, as measured by Differential Scanning Calorimetry (DSC).

[0065] Preferably, the cosmetic composition used according to the invention comprises at least one oil. Examples of oils that may be mentioned include fatty alcohols, fatty esters, hydrocarbons of plant or mineral origin, triglycerides and vegetable oils containing them, and mixtures thereof. Fatty alcohols that may be mentioned include branched and / or unsaturated C10-C20 fatty alcohols such as octyldodecanol and oleyl alcohol.Examples of fatty esters are esters of acids and monoalcohols chosen from: mono- and polyesters of linear saturated C2-C10 (preferably C6-C10) acids and linear saturated C10-C18 (preferably C10-C14) monoalcohols, mono- and polyesters of linear saturated C10-C20 acids and branched or unsaturated C3-C20 (preferably C3-C10) monoalcohols; mono- and polyesters of branched or unsaturated C5-C20 acids and branched or unsaturated C5-C20 monoalcohols; mono- and polyesters of branched or unsaturated C5-C20 acids and linear C2-C4 monoalcohols.Examples of such fatty esters include coco caprate and caprylate mixture, ethyl macadamiate, shea butter ethyl ester, isostearyl isostearate, isononyl isononanoate, ethylhexyl isononanoate, hexyl neopentanoate, ethylhexyl neopentanoate, isostearyl neopentanoate, isodecyl neopentanoate, isopropyl myristate, octyldodecyl myristate, isopropyl palmitate, ethylhexyl palmitate, hexyl laurate, isoamyl laurate, cetostearyl nonanoate, propylheptyl capylate, disopropyl adipate, diethylhexyl adipate, diisopropyl sebacate and diisoamyl sebacate.

[0066] Examples of hydrocarbons include squalane (C30), including plant squalane extracted from olive oil or by biosynthesis, and hemisqualane (Cl 5). Examples of triglycerides are C6-C12 fatty acid triglycerides, such as caprylic and capric acid triglycerides and triheptanoin. Examples of vegetable oils include wheat germ, sunflower, argan, hibiscus, coriander, grape seed, sesame, corn, apricot, castor, shea, avocado, olive, soybean, sweet almond, palm, rapeseed, cottonseed, hazelnut, macadamia, jojoba, alfalfa, poppy, pumpkin, sesame, squash, blackcurrant, evening primrose, lavender, borage, millet, barley, quinoa, rye, safflower, candlenut, passionflower, musk rose, Echium, camelina or camellia.

[0067] The fatty substances may represent from 1 to 30% by weight, preferably from 5 to 25% by weight, and preferentially from 10 to 20% by weight, relative to the total weight of the cosmetic composition.

[0068] The cosmetic composition used according to the invention may also comprise at least one usual cosmetic ingredient, in particular chosen from non-ionic surfactants, cationic surfactants, anionic surfactants, amphoteric surfactants; sunscreens; active ingredients such as vitamins, anti-dandruff agents, anti-seborrheic agents, anti-hair loss and / or regrowth agents; antioxidants; pearlescent and / or opacifying agents; pigments; fillers; sequestering agents; thickeners; non-thickening polymers such as amino silicones and / or cationic polymers; perfumes; preservatives; and mixtures thereof.

[0069] Preferably, the anionic surfactants are chosen from alkylcarbonyl isethionic acid salts, such as those identified under the INCI names SODIUM COCOYL ISETHIONATE and SODIUM COCOYL METHYL ISETHIONATE; lactylic acid salts, such as SODIUM LAUROYL LACTYLATE; N-acylated amino acid salts, such as SODIUM LAUROYL GLYCINATE, SODIUM LAUROYL SARCOSINATE, SODIUM LAUROYL TAURATE and SODIUM OLIVOYL GLUTAMATE; sulfated anionic surfactants, chosen in particular from alkyl sulfate salts, in particular SODIUM COCO SULFATE and POTASSIUM LAURYL SULFATE, C8-C14 alkyl ether sulfate salts such as SODIUM LAURYL ETHER SULFATE; soaps in the form of carboxylic acid salts, including SODIUM OLIVATE and SODIUM PALMITATE; and alkyl ether carboxylic surfactants, such as sodium lauryl ether carboxylic acids or sodium lauryl ether carboxylates.

[0070] The non-ionic surfactant(s) used in the cosmetic composition are preferably chosen from: C8 to C40 alcohols, saturated or unsaturated, linear or branched, oxyethylenated comprising from 1 to 100 moles of ethylene oxide, preferably from 2 to 50, more particularly from 2 to 40 moles of ethylene oxide, preferably comprising one or two fatty chains; oxyethylenated vegetable oils, saturated or unsaturated, comprising from 1 to 100 moles of ethylene oxide, preferably from 2 to 50; alkyl(C8-C30)(poly)glucosides, optionally oxyalkylenated (0 to 10 EO) and comprising 1 to 15 glucose units; sucrose esters such as sucrose stearate and sucrose distearate, C8 to C40 alcohols, mono- or polyglycerolated, comprising from 1 to 50 moles of glycerol, preferably from 1 to 10 moles of glycerol; amides of C8 to C30 fatty acids, saturated or not, linear or branched, oxyalkylenated;esters of C8 to C30 acids, saturated or unsaturated, linear or branched, and of polyethylene glycols; esters of C8 to C30 acids, saturated or unsaturated, linear or branched, and of sorbitol, preferably oxyethylenated; and mixtures thereof.;

[0071] The amphoteric surfactant(s), preferably non-silicone, used in the cosmetic composition used in the present invention, 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. Mention may in particular be made of alkyl(C8-C20)betaines, alkyl(C8-C20)sulfobetaines, alkyl(C8-C20)amidoalkyl(C3-C8)betaines and alkyl(C8-C20)amidalkyl(C6-C8)sulfobetaines.

[0072] The cationic surfactant(s) optionally used in addition to the betainyllysine ester may be chosen from salts of primary, secondary or tertiary fatty amines, optionally polyoxyalkylenated, quaternary ammonium salts, and mixtures thereof.

[0073] The thickener(s) may be selected from cellulosic thickening agents, for example hydroxyethylcellulose, hydroxypropylcellulose and carboxymethylcellulose; gums of natural origin such as Tara gum (Caesalpinia Spinosa) and guar gum and its derivatives, for example hydroxypropyl guar and hydroxypropyltrimonium guar chloride; gums of microbial origin, such as xanthan gum and scleroglucan gum; synthetic thickening agents such as crosslinked homopolymers of acrylic acid or acrylamidopropanesulfonic acid; non-ionic, anionic, cationic or amphoteric associative polymers.Among the cationic polymers which can be used as thickening polymers, mention may be made more particularly of polymers of the polyamine, polyaminoamide and polyquaternary ammonium type, in particular cationic celluloses, cationic guar gums and homopolymers or copolymers of dimethyldiallylammonium halides.

[0074] Examples of active ingredients that may be included in the composition according to the invention are sodium hyaluronate, tocopherol and its derivatives such as tocopheryl acetate, panthenol, serine, glycerin, arginine, ceramides such as 2-oleamido-l,3-octadecanediol, hydroxypropyl starch phosphate and mixtures thereof, without this list being limiting. Mention may also be made of hair conditioning agents such as silicones, in particular dimethicone and amodimethicone.

[0075] Uses

[0076] The cosmetic composition used according to the invention is in the form of a keratin fiber care product, in particular a conditioner or a hair mask intended for treating hair. In particular, it is intended for the treatment of, and therefore preferably applied to, weakened and / or damaged hair, for example by chemical or mechanical treatments, in particular by coloring, bleaching, perming or straightening or by brushing. It can also be used as a treatment cream shampoo, in particular antiseborrheic or anti-dandruff. This composition can constitute a rinse-out or leave-in product. It generally does not have foaming properties. This composition can also be in the form of a rinse-out product, to be applied before or after coloring, bleaching, perming or straightening or between the two stages of a perming or straightening.

[0077] Alternatively, the cosmetic composition according to the invention may be in the form of a beard care product.

[0078] The present invention relates more specifically to a cosmetic process for conditioning keratin fibers, comprising the topical application to the keratin fibers of a cosmetic composition in the form of an emulsion as described above. By "keratin fibers" is meant hair and body hair, in particular the beard and eyebrows. The types of hair to which the composition according to the invention can be applied include Caucasian, African and Asian hair. They can be more or less curly or even frizzy. By "conditioning" is meant, in the context of this description, the improvement of at least one property of the keratin fibers chosen from: their combability, their ability to detangle, their softness, their suppleness, their shine and their manageability.

[0079] The cosmetic composition according to the invention can be applied to dry or wet hair, and preferably to wet or damp hair, i.e. previously washed and rinsed. According to one embodiment, the method according to the invention consists of applying an effective amount of the cosmetic composition to the hair, optionally kneading the hair, optionally leaving the composition on the hair and rinsing. The application time of the composition on the hair can be between a few seconds and 15 minutes and preferably between 30 seconds and 5 minutes. The composition is generally rinsed with water. An optional step of drying the hair can be implemented.In another embodiment, the method according to the invention consists of applying an effective amount of the cosmetic composition to the hair, optionally kneading the fibers, optionally leaving the composition on said fibers, and optionally drying without prior rinsing.

[0080] This process is more particularly intended to improve the combability and / or softness and / or flexibility and / or manageability and / or shine of keratin fibers and / or to smooth them and / or to moisturize them and / or to reduce their static electricity.

[0081] EXAMPLES

[0082] The invention will be better understood in light of the following examples, which are given purely for illustrative purposes and are not intended to limit the scope of the invention, defined by the appended claims. surfactant based on betainyllysine ester derived from octadecanol according to a batched

[0083] Synthesis of glycine betaine hexyl ester

[0084] Glycine betaine (20.0 g, 170.7 mmol, 1 equiv.) and 1-hexanol (64.94 mL, 512.1 mmol, 3 equiv.) are introduced into a 500 mL flask topped with a Dean-Stark flask filled with hexanol. The mixture is refluxed at 150°C at atmospheric pressure. A 70% methanesulfonic acid solution (19.10 mL, 187.8 mmol, 1.1 equiv.) is added. The pressure is reduced to 600 mbar for 1 hour and then gradually to 150 mbar. After 7 hours of reaction, the conversion of glycine betaine is 95%.

[0085] Synthesis of lysine stearate ester

[0086] Lysine hydrochloride (15.0 g, 82.1 mmol, 1 equiv.) and octadecanol (45.8 g, 164.2 mmol, 2 equiv.) are introduced into a 500 mL flask with a distillation assembly. The mixture is refluxed at 150°C at 200 mbar. A 70% methanesulfonic acid solution (17.5 mL, 172.5 mmol, 2.1 equiv.) is added, and the pressure is then gradually reduced to 30 mbar. After 8 hours of reaction, the lysine conversion is 94%.

[0087] Synthesis of Ag-betainyllysine stearic ester

[0088] In a 500 mL flask, the reaction mixture from the synthesis of lysine stearic ester (68.97 g containing 40.0 g, or 67.7 mmol, 1 equiv., of pure stearyl lysinate dimesylate) is introduced with hexanol (49.4 g, 474.2 mmol, 7 equiv.) and the temperature is set at 80°C. Sodium carbonate (21.8 g, 203.2 mmol, 3 equiv.) is added. After 1 h 30 of reaction, the solution of glycine betaine hexyl ester (75.99 g containing 40.3 g, or 135.5 mmol, 2 equiv., of pure hexyl betaine mesylate) is added to the reaction mixture. After 17 hours of reaction, the product is filtered through a hot frit of porosity 3. The hexanol is distilled at 150°C under a pressure ranging from 150 mbar to 5 mbar at the end of distillation. The mass composition of the surfactant composition obtained is as follows: 37% of Afe-betainyllysine stearic ester.7% lysine oligomer ester, 5% glycine betaine, 46% octadecanol and 5% consisting of trace amounts of lysine, distearic ether, stearyl chloride, glycine betaine ester and methane sulfonic acid.

[0089] Example 2: Synthesis of a surfactant composition based on betainyllysine ester derived from octadecanol using a one-pot process

[0090] In a 250 mL two-necked flask, topped with a Dean-Stark flask filled with hexanol, hexanol (38.0 mL, 300 mmol, 3 equiv.) and glycine betaine (23.9 g, 200 mmol, 2 equiv.) are introduced. The set temperature is set at 150°C and the pressure is reduced to 600 mbar. A 70% methanesulfonic acid solution (42.7 mL, 420 mmol, 4.2 equiv.) is added. After 30 minutes of reaction at 600 mbar, the pressure is reduced to 300 mbar for 30 minutes and finally to 150 mbar for 30 minutes. After 1h30 of reaction, the excess hexanol is distilled. The conversion of glycine betaine to glycine betaine ester is 99%. Once the distillation is complete, the set temperature is set at 145°C. Lysine hydrochloride (18.4 g, 100 mmol, 1 equiv.) is added with octadecanol (41.8 g, 150 mmol, 1.5 equiv.). The pressure is lowered to 30 mbar. After 18 h of reaction, the lysine conversion is between 85% and 90%.

[0091] The temperature is set at 100°C and the two-neck flask is topped with a mechanical stirring system and a condenser. Butanol (46.2 mL, 500 mmol, 5 equiv.) is added. Sodium carbonate (26.6 g, 250 mmol, 2.5 equiv.) is introduced slowly according to the foam production. After 7 hours of reaction, the reaction mixture is filtered hot on a porosity 3 frit previously heated to approximately 80°C to remove the salts. Hexanol and butanol are distilled at 130°C under a pressure ranging from 150 mbar to 5 mbar at the end of distillation. The mass composition of the surfactant composition obtained is as follows: between 35-40% of Ae-betainyllysine stearic ester, 5-10% of lysine oligomer ester, 5% of glycine betaine, 35-40% of octadecanol, traces of lysine, distearic ether, stearyl chloride, glycine betaine ester and methane sulfonic acid.

[0092] A variant of this process has been developed by incorporating into the process a preliminary step of decolorization of lysine hydrochloride, in order to significantly reduce the coloration of the final composition (light beige color). The lysine decolorization step is based on treatment with activated carbon in water at a temperature of 80 to 95 °C (preferably 90 °C) for 1 to 3 hours (preferably 2 h).

[0093] Example 3: Synthesis of a surfactant composition based on betainyllysine ester derived from octadodecanol according to a variant of the one-pot process

[0094] In a 250 mL three-necked flask, topped with a Dean-Stark flask filled with hexanol, hexanol (25.8 mL, 203 mmol, 3 eq) and glycine betaine (16.2 g, 135.5 mmol, 2 eq) are introduced. The set temperature is set at 150°C and the pressure at 600 mbar. A 70% methanesulfonic acid solution (28.9 mL, 284.6 mmol, 4.2 eq) is added. After 30 minutes of reaction at 600 mbar, the pressure is reduced to 300 mbar for 30 minutes, then finally to 150 mbar for 30 minutes. After 1h30 of reaction, the excess hexanol is distilled. The conversion of glycine betaine to glycine betaine ester is 99%. In a 50 mL flask, lysine hydrochloride (15 g, 81.3 mmol), activated carbon (1.46 g, 122 mmol) (carbonitalia, Carbofilter RO) and distilled water (14.6 mL, 813 mmol) are stirred at 90°C. After 2 h, the medium is filtered and the resulting filtrate is lyophilized to obtain a white solid.The set temperature of the 250 mL three-necked flask containing glycine betaine ester is set at 145°C. Decolorized lysine hydrochloride (12.5 g, 67.8 mmol, 1 eq) is added, along with octadecanol (28.3 g, 101.6 mmol, 1.5 eq). The pressure is lowered to 30 mbar over 5 minutes. After 18 h of reaction, the lysine conversion is between 85% and 90%.

[0095] The 250 mL three-necked flask is topped with a condenser and a mechanical stirring system. Butanol (31.3 mL, 339 mmol, 5 eq) is added and the temperature is set at 100°C. Sodium carbonate (18.0 g, 169 mmol, 2.5 eq) is added slowly. After 7 h of reaction, the product is filtered through a hot frit of porosity 3. Hexanol and butanol are distilled at 130°C under a pressure ranging from 150 mbar to 5 mbar at the end of distillation. The mass composition of the surfactant composition obtained is as follows: between 35-40% Ne-betainyllysine stearic ester, 5-10% lysine oligomer ester, 5% glycine betaine, 35-40% octadecanol, traces of lysine, distearic ether, stearyl chloride, glycine betaine ester and methane sulfonic acid.

[0096] Example 4: Study of the ecotoxicity of the composition of example 1.

[0097] An ecotoxicity study of the composition obtained in Example 1, according to OECD standards, was carried out. The ecotoxicity results of this surfactant composition demonstrated an excellent profile respectful of humans and the environment. Indeed, according to OECD standard 202 of April 2004, this composition is non-ecotoxic towards both algae and daphnia. The results showed that the ecotoxicity on daphnia by measuring the EC50 at 24h and 48h is greater than 100 mg / L (knowing that the lower the value obtained, the greater the toxicity) and the ecotoxicity on algae by measuring ECr50 and ECr20 at 72h is greater than 100 mg / L.

[0098] Example 5: Stability study of the composition of example 1

[0099] The stearic ester of Ae-betainyllysine in the composition of Example 1 has an ester function between lysine and alcohol that is susceptible to hydrolysis (Figure 3). An assessment of the stability of the bond between the stearic group (octadecyl) and the carboxyl of the stearic ester of M?-betainyl lysine was therefore carried out. To do this, the pH of the selected buffer solution was set at 4.27. This pH value corresponds to that generally found in hair cosmetic products.

[0100] The stability study was carried out on the stearic ester of Ve-betainyllysine after formulation. For this, a formula was made by mixing the stearic ester of Ve-betainyllysine (1% by mass) with a preservative (0.8% by mass) and 4% of a buffer solution pH 4.27. 'H NMR was used to estimate the hydrolysis phenomenon of the stearic ester of Ne-betainyllysine. Thus the samples collected over time were lyophilized, then a deuterated solution (CDCI3 / CD3OD 1:1 v / v) was introduced into the different lyophilizates. The stability between Ae-betainyllysine and the stearic chain was determined based on the integrated area of ​​the signal relative to the CH2O group of the stearic ester of As-betainyllysine (4.19 ppm) and that of the CH2N(CHs)3 group + of JVe-betainyllysine (4.13 ppm) released into the medium over time.

[0101] The behavior of As-betainyllysine stearic ester at room temperature, 40°C and 50°C is illustrated in Figures 4 to 6. It is observed that As-betainyllysine stearic ester exhibits very good stability, particularly after 1 month of study at 50°C (degradation of only 17%).

[0102] Example 6: Evaluation of the detangling effect

[0103] A conditioner emulsion containing 1% of the stearic ester of A-betainyllysine from the composition of Example 1 was prepared. To do this, water and 2.7% of the surfactant composition of Example 1 were heated separately to 80°C. The surfactant composition was then added to the water with stirring for about ten minutes. The resulting emulsion was cooled and then 4% of a buffer solution (pH 4.27) and 0.8% of a preservative were added.

[0104] An evaluation of combing on wet hair was carried out after storing the emulsion for 24 hours at room temperature, 1 month at 50°C and 3 months at 40°C.

[0105] To perform this test, a Diastron® Fibra One device equipped with a comb is used to measure the work (in Joules) required to travel through a strand of hair. To do this, five calibrated strands (3.5 g; 28 cm) of bleached Caucasian hair are first washed with 1 mL of Sodium Lauryl ether sulfate solution (28% active ingredient). The strands are rubbed 20 times between the hands, then rinsed for 1 min 30 s with water. This washing is then repeated twice, and the excess water is removed by wringing the strand 3 times between 2 fingers.

[0106] The device is set as follows:

[0107] Starting position: 75 mm

[0108] Combing length: 200 mm

[0109] Speed: 2000 mm / min

[0110] Three measurements are taken for each strand, namely one measurement after each rinsing step, then the average of the three measurements is calculated.

[0111] The same conditioning treatment (0.5 mL) is then applied to one side of each of the five strands, then the product is spread 10 times with two fingers before being applied (0.5 mL) to the other side of the strand and then spread 10 times with two fingers. The strands are then each rinsed for 16 seconds with tap water (changing sides every 8 seconds). Excess water is removed by squeezing 3 times between 2 fingers with the same force. The strands are then tested again with the Diastron® as described above. Then they are subjected to two successive rinses (passing under the tap for 10 seconds then removing the excess water by squeezing 3 times between 2 fingers) and again passed through the Diastron® after each rinse. The average of the three measurements obtained is calculated.

[0112] For each strand, the percentage reduction in the force required to disentangle the strand is then determined using the following formula: D = (WT - Wo) / 100, where WT is the work measured after treatment and Wo is the work measured before treatment. The average DM of the percentage reductions obtained for the five strands is then calculated.

[0113] The results of these tests are illustrated in Figure 7. As can be seen from this Figure, the three formulations similarly show good detangling efficiency which validates the conditioning effect of the surfactant compositions as well as the stability of the active molecule under the usual stability conditions of cosmetic products. Example 7: Formulations

[0114] Several types of products can be prepared using the betainyllysine esters or surfactant compositions according to the invention. Examples of such products are indicated below, with the ingredients in capital letters being identified by their INCI names.

[0115] Hair Mask:

[0116] Table 1

[0117] 2 in 1 solid shampoo:

[0118] Table 2

[0119] 2 in 1 liquid shampoo:

[0120] Table 3 Solid conditioner:

[0121] Table 4

[0122] Beard balm:

[0123] Table 5

Claims

Claims 1. Betainyllysine ester of formula (I): in which: X is an organic or inorganic anion, the radical Ri is a -NH2 or -NH3 group. the radical R2 is a C12-C24 alkyl or alkenyl group.

2. Betainyllysine ester according to claim 1, characterized in that the radical R2 is chosen from the groups lauryl (C12:0), myristyl (C14:0), cetyl (C16:0), palmitoleyl (C16:1), stearyl (C18:0), oleyl (C18:1), linoleyl (C18:2), linolenyl (C18:3), arachidyl (C20:0), arachidonyl (C20:4), behenyl (C22:0), 2-hexyldecyl (C16R:0), 2-octyldodecyl (C20R:0) and 2-decyltetradecyl (C24R:0).

3. Betainyllysine ester according to claim 1 or 2, characterized in that flag X is chosen from a chloride, a sulfate, a perchlorate, an alkyl sulfate ion, in particular decyl sulfate or lauryl sulfate, an aryl sulfonate ion, in particular benzene sulfonate, paratoluene sulfonate, an alkylsulfonate ion, in particular triflate, methanesulfonate, ethanesulfonate, decylsulfonate, laurylsulfonate, camphorsulfonate, or a sulfosuccinate ion, preferably from alkylsulfonates and arylsulfonates, more particularly from methanesulfonate, triflate, paratoluenesulfonate and camphorsulfonate ions, better still, X is the methanesulfonate or ethanesulfonate ion.

4. A process for preparing the betainyllysine ester as defined in any one of claims 1 to 3, comprising the following steps: (a) esterification of glycine betaine or one of its salts with at least one C4-C8 monoalcohol in the presence of at least one organic or inorganic acid XH, to obtain a glycine betaine ester salt, (b) esterification of L-lysine or one of its salts with at least one linear or branched, saturated or unsaturated, C12-C24 monoalcohol R2-OH in the presence of at least one organic or inorganic acid XH, to obtain a lysine fatty ester salt, (c) diluting the lysine fatty ester salt with at least one solvent such as a C4-C8 monoalcohol, (d) adding to the diluted lysine fatty ester salt at least one organic or inorganic base, so as to obtain a lysine fatty ester, (e) aminolysis of the glycine betaine ester salt obtained in step (a) by reaction with the lysine fatty ester obtained in step (d), (f) filtration of insoluble matter, then removal of residual C4-C8 monoalcohol.

5. A process for preparing the betainyllysine ester as defined in any one of claims 1 to 3, comprising the following steps: (a) esterification of glycine betaine or one of its salts with at least one C4-C8 monoalcohol in the presence of at least one organic or inorganic acid XH, then removal of the residual C4-C8 monoalcohol to obtain a glycine betaine ester salt, (b) addition of L-lysine or one of its salts and esterification thereof with at least one linear or branched, saturated or unsaturated, C12-C24 monoalcohol R2-OH, to obtain a reaction mixture comprising a lysine ester salt, (c) fluidification of the reaction mixture, by adding a solvent such as a C4-C8 monoalcohol, (d) aminolysis of the glycine betaine ester salt by the lysine ester by adding to the fluidized reaction mixture at least one organic or inorganic base, (e) filtration of the insoluble materials present in the reaction medium, then elimination of the solvent.

6. Method according to claim 4 or 5, characterized in that the C4-C8 monoalcohol is chosen from the group consisting of: butanol, pentanol, 3-methylbutan-1-ol, fusel alcohol, hexanol, heptanol, octanol and mixtures thereof, preferably butanol or hexanol.

7. Method according to any one of claims 4 to 6, characterized in that the L-lysine salt is L-lysine hydrochloride.

8. Surfactant composition containing: - at least one betainyllysine ester of formula (I), as defined in any one of claims 1 to 3, preferably in an amount of 35 to 50% by weight, - at least one fatty alcohol R2-OH, preferably in an amount of 35 to 50% by weight, - a lysine ester of formula (II): H2N-(CH2)4-CH(NH2)-COOR.2 (II), where R2 is a linear or branched, saturated or unsaturated, C12-C24 monoalcohol residue R2-OH, preferably in an amount of 5 to 10% by weight, - glycine betaine, preferably in an amount of 3 to 10% by weight, - other by-products, chosen from L-lysine, a fatty alcohol ether R2-O-R2, an alkyl chloride CI-R2, a glycine betaine ester salt of formula (III): (CH3)3-N + -CH2-COORI, where Ri is a C4-C8 monoalcohol residue, an acid XH and their mixtures, preferably in a total quantity of 0.5 to 5% by weight, these compounds being found for at least some in salified form by a base X' and the above percentages being related to the total weight of the surfactant composition.

9. Cosmetic composition in the form of an emulsion comprising, in a physiologically acceptable medium, a betainyllysine ester as defined in any one of claims 1 to 3.

10. Cosmetic process for conditioning keratin fibers, comprising the topical application to the keratin fibers, such as the hair, beard and / or eyebrows, of a cosmetic composition according to claim 9.

11. Method according to claim 10, characterized in that it is intended to improve the combability and / or softness and / or flexibility and / or manageability and / or shine of keratin fibers and / or to smooth them and / or to hydrate them and / or to reduce their static electricity.

12. Use as a conditioning agent for keratin fibers of a betainyllysine ester according to any one of claims 1 to 3 or of a surfactant composition according to claim 8.

Images