A process for treating keratin fibers comprising the application of a composition based on a particular chitosan compound

Abstract

The present invention relates to the cosmetic field of keratin fibers, and in particular to the shaping and / or protection of the artificial color of keratin fibers, preferably hair, and more specifically in a high-humidity environment. It aims to provide a process for treating keratin fibers comprising at least one step of applying to said keratin fibers a composition T comprising at least one specific chitosan compound.

Description

Title of the invention: A method for treating keratin fibers comprising the application of a composition based on a particular chitosan compound

[0001] The present invention relates to the cosmetic field of keratin fibers, and in particular to that of shaping and / or protecting the artificial color of keratin fibers, preferably hair, and more particularly in a high-humidity environment. It thus aims to provide a process for treating keratin fibers comprising at least one step of applying to said keratin fibers a composition T comprising at least one specific chitosan compound.

[0002] Due to their nature, certain hair types are more sensitive to humidity and may therefore tend to frizz, which can cause an increase in hair volume. These hair types are then particularly difficult to style in humid conditions.

[0003] In order to remedy this, it is common to use hair compositions based on silicone raw materials which can however give the hair a greasy and heavy feel or based on oils whose conditioning effect may tend to fade quickly over time, being in particular not very resistant to external aggressions, especially to shampoos.

[0004] Furthermore, the formulation of environmentally friendly cosmetic products, that is to say, whose design and development take into account environmental issues, is becoming a major concern in order to help meet global challenges.

[0005] It is therefore essential to propose more sustainable compositions and / or preparation processes and / or ingredients to address these environmental challenges, particularly by reducing the use of petrochemical-derived compounds. In this context, it is important to develop cosmetic product and / or cosmetic ingredient preparation processes with a lower carbon footprint, capable of reducing carbon dioxide generation throughout the product's life cycle and / or using minimal energy and water and / or employing greener solvents and / or requiring fewer synthesis steps and / or achieving good atom economy.

[0006] Thus, there is a real need to find a way to remedy these drawbacks, in particular to facilitate hair styling in humid environments by sustainably limiting (in particular permanently to at least one shampoo) the formation of frizz and / or the increase in hair volume in humid conditions.

[0007] Furthermore, colored hair tends to become damaged and / or the color to fade over time due to exposure to UV rays and / or shampoos, particularly after 10 shampoos.

[0008] It is also of interest to make available processes for treating keratin fibers that protect the artificial color of hair, in particular allowing the reduction of the loss of intensity of the artificial color, more particularly following several repeated shampoos after hair coloring.

[0009] It is also of interest to develop non-coloring treatment processes allowing the durable shaping of keratin fibers, protecting the fibers from humidity, in particular exhibiting good hair hold in high humidity.

[0010] The present invention is specifically aimed at meeting all or part of these needs.

[0011] The present invention therefore relates to a process for treating keratin fibers comprising at least one step of applying to said keratin fibers a composition T comprising at least one chitosan compound of the following general formula (P): ** (P)

[0012] in which: - RI independently represents a hydrogen atom or a group -(CH2CH(R')O)qH in which: - q denotes an integer ranging from 1 to 20,

[0013] - R' independently represents a hydrogen atom, a methyl group or a hydroxyl group, preferably a hydrogen atom; - R”' represents a C5-C29 hydrocarbon radical, saturated or unsaturated, linear or branched, possibly substituted by at least one hydroxyl group, it being understood that at least one of the RI radicals is different from hydrogen;

[0014] - n is a number representing 50% to 99.9% of the sum n + m + p, - m is a number representing 0% to 25% of the sum n + m + p, - p is a number representing 0.1% to 30% of the sum n + m + p, and - the sum n + m + p being equal to 100%.

[0015] It has been observed that, when the process according to the invention is a process for shaping keratin fibers, it makes it easy to obtain a hairstyle of keratin fibers, in particular hair, which is durable over time and more particularly resistant to a high humidity environment.

[0016] It has also been observed that, when the process according to the invention is implemented on artificially colored keratin fibers, it makes it possible to maintain the intensity of the artificial color of the keratin fibers, in particular of hair, even after at least ten shampoos.

[0017] For the purposes of the present invention, and unless otherwise indicated: - the expression "at least one" is equivalent to the expression "one or more" and can be substituted for it. - the expression "between... and..." is equivalent to the expression "ranging from... to..." and can be substituted for it, and implies that the limits are included. - By the expression "greater than" and respectively the expression "less than" in the meaning of the present invention, we mean an open interval that is strictly greater than, respectively strictly less than, and therefore that the bounds are not included. - For the purposes of this application, "keratin fibers" refers particularly to human keratin fibers such as hair, eyelashes, eyebrows, and body hair, preferably hair, eyebrows and eyelashes, and even more preferably hair. - For the purposes of this invention, "hair" means the hair on the head. This term does not include body hair, eyebrows, or eyelashes.

[0018] - For the purposes of this document, "residual shampoo color" means invention that the color obtained persists after at least one shampoo, particularly after at least 3 shampoos, preferably at least 5 shampoos, better at least 10 shampoos.

[0019] - an "alkyl" radical is a saturated hydrocarbon radical, linear or branched, in particularly in Ci-C6, preferably in Ci-C4;

[0020] - an "alkoxy" radical is an alkyl-oxy radical for which the alkyl radical is a hydrocarbon radical, linear or branched, in Ci-C6 preferably in CrC4;

[0021] - a "(poly)(hydroxy)alkyl" radical designates a Ci-C6 alkyl radical, of preferably in Ci-C4 possibly substituted by one or more hydroxy radicals, preferably substituted by 1 to 4 hydroxy groups, more particularly between 1 and 3;

[0022] - by "organic or mineral acid salt", more particularly means a) the addition salts with a particular organic or mineral acid chosen from a salt derived i) from hydrochloric acid HCl, ü) from hydrobromic acid HBr, iii) from sulfuric acid H2SO4, iv) from alkylsulfonic acids: Alk-S(O)2OH such as methylsulfonic acid and ethylsulfonic acid; v) from arylsulfonic acids: Ar-S(O)2OH such as benzenesulfonic acid and toluenesulfonic acid; vi) from alkoxysulfinic acids: Alk-OS(O)OH such as methoxysulfinic acid and ethoxysulfinic acid; vii) from aryloxysulfinic acids such as tolueneoxysulfinic acid and phenoxysulfinic acid; viii) from phosphoric acid H3PO4; ix) of triflic acid CF3SO3H and x) of tetrafluoroboric acid HBF4;xi) of carboxylic organic acids R°-C(O)-OH (l'z) formula (Fz) in which R° represents a (hetero)aryl group such as phenyl, (hetero)aryl(Ci-C4)alkyl such as benzyl, or (Ci-Cio)alkyl said alkyl group being optionally substituted preferably by one or more hydroxy groups, amino radicals, or carboxy groups, R° preferably designating a (Ci-C6)alkyl group optionally substituted by 1, 2 or 3 hydroxy groups, or more preferably the monocarboxylic acids of formula (l'z) are chosen from acetic acid, glycolic acid, lactic acid, and mixtures thereof, and more particularly from acetic acid and lactic acid; and the polycarboxylic acids are chosen from tartaric acid, succinic acid, fumaric acid, citric acid and mixtures thereof;and xii) amino acids having more carboxylic acid radicals than amino groups such as gamma-carboxyglutamic acid, aspartic acid, glutamic acid, in particular gamma-carboxyglutamic acid; or b) addition salts with an organic or mineral base such as hydroxides of alkali metals, alkaline earth metals, carbonates of alkali metals or alkaline earth metals, bicarbonates of alkali metals or alkaline earth metals, addition salts with so-called basic amino acids such as arginine, lysine, addition salts with amines possibly hydroxylated;

[0023] - an "anionic counterion" is an anion or an associated anionic group to the cationic charge; more particularly the anionic counter-ion is chosen from i) halides such as chloride, bromide; ii) nitrates; iii) sulfonates including the Ci-C6 alkylsulfonates: Alk-S(O)2O such as methylsulfonate or mesylate and ethylsulfonate; iv) arylsulfonates: Ar-S(O)2O such as benzenesulfonate and toluenesulfonate or tosylate; v) citrate; vi) succinate; vii) tartrate; viii) lactate; ix) alkyl sulfates: Alk-OS(O)O such as methyl sulfate and ethyl sulfate; x) aryl sulfates: Ar-OS(O)O such as benzene sulfate and toluene sulfate; xi) alkoxysulfates: Alk-OS(O)2O such as methoxysulfate and ethoxysulfate; xii) aryloxysulfates: Ar-OS(O)2 O, xiii) phosphate; xiv) acetate; xv) triflate; and xvi) borates such as tetrafluoroborate.

[0024] - The "solvates" represent the hydrates as well as the association with alcohols linear or branched C1-C4 linear or branched such as ethanol, isopropanol, n-propanol;

[0025] - By "anhydrous" is meant a quantity of less than 5% by weight of water, preferably less than 3% by weight of water, better less than 1% by weight of water, relative to the total weight of the composition in question, even more preferably the composition in question is free of water.

[0026] - The terms "coloring agent" and "coloring matter" are equivalent;

[0027] Unless otherwise indicated, the quantities shown are expressed as a percentage mass. Chitosan compound

[0028] According to the process of the invention, composition T comprises at least one chitosan compound of the following formula (P): in which:

[0029] - RI independently represents a hydrogen atom or a group -(CH2CH(R')O)qH in which: - q denotes an integer ranging from 1 to 20,

[0030] - R' independently represents a hydrogen atom, a methyl group or a hydroxyl group, preferably a hydrogen atom; - R”' represents a C5-C29 hydrocarbon radical, saturated or unsaturated, linear or branched, possibly substituted by at least one hydroxyl group, it being understood that at least one of the RI radicals is different from hydrogen; - n is a number representing 50% to 99.9% of the sum n + m + p, - m is a number representing 0% to 25% of the sum n + m + p, - p is a number representing 0.1% to 30% of the sum n + m + p, and - the sum n + m + p being equal to 100%.

[0031] In other words, the compound (P) comprises two units repeated respectively n and p times, different from each other, and possibly a third unit repeated m times.

[0032] Chitosan compounds of formula (P) do not comprise any units other than the units repeated respectively n, m and p times.

[0033] Preferably, the compound (P) does not include a unit repeated m times.

[0034] Preferably, the radical R'" represents a hydrocarbon radical in C7-C2 3, more preferably in Ci rCi 9, better in C13-C17 such as C15. Advantageously, the radical R'" is saturated, in particular linear and more particularly unsubstituted by at least one hydroxyl group.

[0035] Preferably, m is a number representing 0% to 15% of the sum n+m+p, preferably 0% to 10% of the sum n+m+p.

[0036] Preferably, p is a number representing 1% to 15% of the sum n+m+p, preferably 5% to 10% of the sum n+m+p.

[0037] According to a preferred embodiment of the invention, the compound (P) is such that: - n is a number representing from 70% to 99.9%, better from 80% to 98%, even better from 85% to 97%, of the sum n+m+p, - m is equal to 0%, and - p is a number representing from 0.1% to 30%, or better yet from 3% to 15%, of the sum n+m +p.

[0038] Preferably, the average molecular weight by weight (Mw) of the compound (P) is in the range of 10,000 to 1,500,000 g / mol; more preferably from 15,000 to 1,000,000 g / mol; more preferably still from 20,000 to 500,000 g / mol.

[0039] Advantageously, the total content of chitosan compound of formula (P) in composition T is in the range of 0.001% to 30% by weight, preferably from 0.001% to 20% by weight, more preferably from 0.005% to 10% by weight, even more preferably from 0.01% to 5% by weight, better from 0.01% to 2%, relative to the total weight of composition T.

[0040] Coloring agent: According to one embodiment, composition T may further comprise at least one coloring agent selected from pigments, direct colorants, and mixtures thereof.

[0041] Preferably, composition T is free of coloring agents. By "free of coloring agents," we mean a composition comprising a coloring agent content of less than 1% by weight, more preferably less than 0.5% by weight, better less than 0.2% by weight, even better less than 0.1% by weight, and always better less than 0.05% by weight, relative to the weight of the composition. Better still, it contains no coloring agents (0%). More specifically, a composition free of coloring agents does not include any coloring agents added during its preparation; residual coloring agents possibly present which may originate from the raw materials used during preparation. Organic solvent

[0042] According to the process of the invention, the composition T may optionally include further one or more organic solvents.

[0043] Examples of organic solvents include: a) C2-C6 alkanols, such as ethanol and isopropanol; b) water-miscible polyols at room temperature (25 °C), in particular polyols having from 2 to 10 carbon atoms, preferably from 2 to 6 carbon atoms, such as glycerin, propylene glycol, 1,3-propanediol, butylene glycol, pentylene glycol, hexylene glycol, dipropylene glycol, diethylene glycol, diglycerin; c) polyol ethers such as 2-butoxyethanol, propylene glycol monomethyl ether, diethylene glycol monoethyl ether and monomethyl ether, and d) aromatic alcohols such as benzyl alcohol or phenoxyethanol, and mixtures thereof.

[0044] According to the invention, organic solvents do not carry amine or thiol functions and are in particular different from amino-alkanols such as diaminopropanols.

[0045] Preferably, the organic solvent(s) are chosen from polyols, preferably from polyols having 2 to 10 carbon atoms, more preferably having 2 to 6 carbon atoms, such as ethanol or glycerin.

[0046] Advantageously, the composition T is aqueous or hydroalcoholic (advantageously an ethanol / water mixture in particular in a volume ratio between 1 / 99 and 99 / 1, more particularly between 10 / 90 and 90 / 10, even more particularly between 20 / 80 and 80 / 20, preferably 40 / 60 to 60 / 40 such as 50 / 50).

[0047] Preferably, the total content of organic solvent(s) in composition T is in the range of 1% to 90% by weight, more preferably 30% to 80% by weight, more preferably 35% to 70% by weight, and even better 40% to 60% by weight, relative to the total weight of composition T.

[0048] Preferably, composition T further comprises water.

[0049] Preferably, the total water content in composition T is included in the range from 1% to 90% by weight, more preferably from 30% to 80% by weight, more preferably from 35% to 70% by weight, and even better from 40% to 60% by weight, relative to the total weight of composition T.

[0050] Preferably, when composition T includes water, the pH of composition T is between 2 and 10, more preferably between 3 and 6, better between 3 and 4.5.

[0051] According to a preferred embodiment, the pH of composition T is acidic, preferably less than 6, more preferably less than or equal to 5, even more preferably the pH of composition T is between 3 and 5.

[0052] The pH can be adjusted to the desired value by means of alkalizing agents or acidifying agents commonly used.

[0053] Among the acidifying agents, examples include mineral or organic acids such as hydrochloric acid, orthophosphoric acid, carboxylic acids such as acetic acid, tartaric acid, citric acid, lactic acid, sulfonic acids.

[0054] Among the alkalizing agents, ammonia, mineral or organic hydroxides can be cited.

[0055] Composition T may further contain additives commonly used in cosmetics, such as antifoaming agents, thickening agents, moisturizing agents, clays, mineral fillers, UV filters, perfumes, anionic, cationic, nonionic or amphoteric surfactants, vitamins, preservatives, silicones, waxes, and mixtures thereof. These additives may be present in composition T according to the invention in an amount ranging from 0 to 20% by weight relative to the total weight of composition T.

[0056] A person skilled in the art will take care to choose any such additives and their quantities so that they do not impair the properties of the compositions of the present invention.

[0057] Composition T can be used on wet or dry hair, in rinsed or unrinsed mode.

[0058] Composition T may optionally be formulated as a suspension, dispersion, gel, emulsion, in particular an oil-in-water (O / W) or water-in-oil (W / O) emulsion, or multiple emulsions (W / O / W or polyol / O / W or O / O / O), in the form of a cream, foam, stick, vesicle dispersion, in particular of ionic or non-ionic lipids, bi-phase or multi-phase lotion. Process

[0059] The process according to the invention is a process for treating keratin fibers comprising at least one step of applying a composition T comprising at least one chitosan compound of formula (P) as defined above.

[0060] Preferably, the process of the invention is a process for treating keratin fibers for the protection of the artificial color of keratin fibers and / or for shaping keratin fibers, preferably in a high humidity environment.

[0061] The application of composition T can be carried out on dry or wet keratin fibers, as well as on all types of keratin fibers, light or dark, natural or colored, permed, bleached or straightened.

[0062] The application of composition T to keratin fibers is generally carried out at room temperature (between 15 and 30°C).

[0063] The application of composition T may optionally take place after the application of a shampoo.

[0064] After applying composition T, and possibly after applying shampoo, mechanical action can be exerted on the keratin fibers such as combing, brushing, passing with fingers, preferably combing.

[0065] After the application of composition T, and after possibly the application of a shampoo and possibly combing, a waiting period can be carried out.

[0066] In particular, during the exposure time, one can wait between 1 minute and 1 hour, preferably between 5 minutes and 30 minutes, more preferably between 5 and 20 minutes.

[0067] Heating can also be done during the exposure time, in particular with a heating tool such as a Climazon or a hairdryer.

[0068] After application of composition T, the keratin fibers can be rinsed with water.

[0069] After application of composition T, and after possibly rinsing with water, the keratin fibers can be left to dry or dried, for example at a temperature greater than or equal to 30 °C.

[0070] The process according to the invention can thus include a step of applying heat to the keratin fibers using a heating tool.

[0071] The heat application step of the process of the invention can be carried out using a helmet, a hair dryer, a straightening or curling iron, or a Climazon. Preferably, the heat application step of the process of the invention is carried out using a hair dryer.

[0072] During the heat application step on the keratin fibers, a mechanical action on the strands can be exerted such as combing, brushing, passing with fingers.

[0073] When the heat application step on the keratin fibers is carried out using a helmet or a hair dryer, the temperature is preferably between 30 and 110°C, preferably between 50 and 90°C.

[0074] Preferably, if the keratin fibers are dried, they are dried not only with heat but also with an airflow. This airflow during drying improves the individualization of the sheathing.

[0075] Thus another object of the invention is the use of one or more chitosan compounds (P) or of a composition T comprising them to protect keratin fibers from moisture, preferably to limit the formation of frizz and / or the increase in hair volume in a high humidity environment, the compound(s) (P) being as defined above.

[0076] The invention also relates to the use of one or more chitosan compounds (P) or of a composition T comprising them to protect the artificial color of keratin fibers, preferably to increase the resistance of the color to shampooing; the compound(s) (P) being as defined above.

[0077] The following examples serve to illustrate the invention without, however, being limiting in nature. Examples

[0078] Example 1: Process for the synthesis of Palmitoyl Glycol Chitosan

[0079] In a 20 L double-jacketed container, equipped with a thermometer and a stirrer, 68.24 g of 2,5-dioxopyrrolidin-l-yl palmitate and 12 L of an ethanol / methanol mixture at a volume ratio of 95 / 5 were introduced under stirring at a temperature of 30°C for 1 hour.

[0080] In the reaction medium, 6 kg of water are then introduced followed by 30 g of sodium bicarbonate, and then said medium was stirred until the sodium bicarbonate was dissolved.

[0081] After dissolving the sodium bicarbonate, 40 g of chitosan glycol were added, and the mixture was stirred at 35°C for 1 hour. The solution was then cooled to 25°C, and 2 L of an ethanol / methanol mixture at a volume ratio of 95 / 5 were added. The solution was then stirred for 6 days.

[0082] After 6 days, the reaction medium was distilled under vacuum and the suspension was transferred into dialysis tubes and then dialyzed in water for 4 days, with the water being renewed every 4 hours (except at night).

[0083] The dialysis tubes were then opened and the recovered white sludge was dried for several days in a ventilated tube set at 40°C to give 53.3 g of a light brown solid. Example 2

[0084] Compositions 1 and 2 as described in Table 2 were prepared: quantities are expressed in g of raw material as is / 100g, unless otherwise stated.

[0085] [Tables 2] Ingredients Compositions 1 I2 (Comp.) (Inv.) Palmitoyl Glycol Chitosan from example 1 - 0.1 Water / ethanol (1 / 1 w / w) Qsp 100 Qsp 100 Hydrochloric acid Qsp pH = 3.3 - Measured pH 3.3 3.3

[0086] Protocol:

[0087] A PI (comparative) process and a P2 (invention) process were implemented on strands of natural hair weighing 2.7g and 27cm long.

[0088] Processes P1 and P2 consist of applying formula 1 and formula 2, respectively, to the hair strands, at a rate of 1 g of formula per gram of hair. The hair strands were then left for 15 minutes at a temperature of 33°C. The excess formula on the hair was then removed by pressing the hair between the thumb and forefinger and repeating the operation a second time. The hair strands were then left to dry in an oven at 60°C for 10 minutes.

[0089] The hold of the hairstyle at high humidity, i.e. the increase in the volume of the hair in a humid environment, was evaluated on the strands of hair treated by the PI and P2 processes.

[0090] Evaluation of the hold of the hairstyle in high humidity

[0091] The hair samples treated by the PI and P2 processes were placed in a glove box at 20% relative humidity at 25°C for a period of 2 hours and then at 80% humidity at 25°C for a period of 24 hours.

[0092] Volume and frizz measurements, measured by measuring the width of the strands at mid-height, were performed after 24 hours at 80% relative humidity on samples treated with the P2 process. These measurements were then compared with those performed after 24 hours at 80% relative humidity on reference hair samples treated with the PL process.

[0093] The results are summarized in Table 3 below:

[0094] [Tables3] Method Width of strands at mid-height (cm) Observations PI (comparative) 4.5 Poor hairstyle hold P2 (invention) 2.1 Good hairstyle hold

[0095] The width of the strands at mid-height is higher for strands treated with the PI process and subjected to a relative humidity of 80% for 24 hours than those treated with the P2 process and subjected to the same conditions.

[0096] Thus, the P2 process according to the invention allows for improved hold of the hairstyle at high humidity compared to the PI process.

[0097] In addition, the P2 process according to the invention makes it possible to limit the increase in hair volume compared to the PI process. Example 3

[0098] Compositions 3 to 6 as described in Table 4 below were prepared.

[0099] [Tables4] Ingredients Compositions 3 (comparative) 4 (invention) 5 (invention) 6 (invention) Palmitoyl Glycol Chitosan of example 1 0 0.1 0.5 1.0 Water / ethanol (1 / 1 w / w) Qsp 100 Qsp 100 Qsp 100 Qsp 100 Lactic acid or NaOH Qsp pH = 4 Qsp pH = 4 Qsp pH = 4 Qsp pH = 4

[0100] Protocol:

[0101] Four processes were implemented on 1g strands of hair previously damaged by two bleachings and then colored with Majirel® 6.66 coloring (L'Oréal).

[0102] According to processes P3 to P6, the colored hair strands are combed, moistened under water at 37°C before being passed between the fingers 5 times for 5 seconds. The hair strands are then squeezed between two fingers.

[0103] A standard shampoo (Garnier Ultra Doux) is applied evenly to the colored strands at a rate of 0.4g of standard shampoo per gram of strands, gently massaging the strands of hair along their length (6 passes) for 15 seconds, from root to tip.

[0104] The strands of hair are then placed in a watch glass and left to rest for 1 minute.

[0105] Next, the strands of hair are rinsed with water by passing the strand between the fingers (15 passes), then squeezed between two fingers.

[0106] The hair strands are then placed on a bench and formulas 3 to 6, respectively, were applied to the hair strands using a pipette, at a rate of 0.5g of formula per gram of hair.

[0107] Then the strands are combed 5 times and left to rest for 5 minutes before being squeezed between two fingers and then dried with a hairdryer.

[0108] This protocol, including the shampooing step, application of formulas 3 to 6, rinsing and drying, is subsequently repeated 14 times (15 applications in total).

[0109] The P3 process (application of composition 3 to the wicks) is a comparative process.

[0110] The processes P4 to P6 (application of compositions 4 to 6 respectively on the wicks), are processes according to the invention.

[0111] The persistence of color to shampoos was evaluated on hair strands treated by processes P3 to P6. Evaluation of the persistence of shampoos

[0112] The persistence of the color of the highlights was evaluated in the CIE L*a*b* system, using a Minolta CM3610d spectrophotometer (illuminant D65, angle 10°, specular component included).

[0113] In this L*a*b* system, L* represents the intensity of the color, a* indicates the green / red color axis and b* the blue / yellow color axis.

[0114] The color permanence is evaluated by the color difference AE between the colored strands before shampooing, and then after 15 shampoos. The lower the AE value, the more the color persists through shampooing. The value of AE is calculated according to the following equation: AE = V(P - + (a* - a0>y + (b* -

[0115] In this equation, L*, a* and b* represent the values ​​measured after hair coloring and after undergoing 15 shampoos, and Lo*, a0* and b0* represent the values ​​measured after hair coloring and before 15 shampoos.

[0116] The results are summarized in Table 5 below:

[0117] [Tables5] Process After coloring After 15 shampoos AE Lo* a0* b0* L* a* b* P3 (comparative) 19.5 16.2 6.8 30.1 20.8 13.6 13.4 P4 (invention) 20.1 17.3 7.2 21.1 19.3 8.0 3.8 P5 (invention) 17.3 11.0 4.2 18.7 11.9 4.6 1.7 P6 (invention) 17.3 13.3 5.0 17.2 13.2 4.5 2.2

[0118] The colored hair strands treated by the processes P4 to P6 according to the invention exhibit improved shampoo retention compared to the colored hair strands treated by the comparative process P3.

Claims

1. Demands A process for treating keratin fibers comprising at least one step of applying to said keratin fibers a composition T comprising at least one chitosan compound of the following general formula (P):

2. in which: - RI independently represents a hydrogen atom or a group -(CH2CH(R')O)qH in which: - q denotes an integer ranging from 1 to 20, - R' independently represents a hydrogen atom, a methyl group or a hydroxyl group, preferably a hydrogen atom; -R'” represents a C5-C29 hydrocarbon radical, saturated or unsaturated, linear or branched, possibly substituted by at least one hydroxyl group, it being understood that at least one of the RI radicals is different from hydrogen; - n is a number representing 50% to 99.9% of the sum n + m + P, - m is a number representing 0% to 25% of the sum n + m + p, - p is a number representing 0.1% to 30% of the sum n + m + p, and - the sum n + m + p being equal to 100%. Method according to claim 1, characterized in that m is a number representing from 0% to 15% of the sum n + m + p, preferably from 0% to 10% of the sum n+m+p.

3. A method according to any one of the preceding claims, characterized in that p is a number representing 1% to 15% of the sum n+m+p, preferably 5% to 10% of the sum n+m+p.

4. A process according to any one of the preceding claims, characterized in that the radical R”' of the compound (P) represents a hydrocarbon radical in C7-C2 3, more preferably in Ci rCi 9, better in C13-C17 such as C15.

5. A method according to any one of the preceding claims, characterized in that the compound (P) is such that: - n is a number representing from 70% to 99.9%, better from 80% to 98%, of the sum n+m+p, - m is equal to 0%, and - p is a number representing from 0.1% to 30%, better from 3% to 15%, of the sum n+m+p.

6. A process according to any one of the preceding claims, characterized in that the average molecular weight by weight (Mw) of the compound (P) is in the range of 10,000 to 1,500,000 g / mol; more preferably from 15,000 to 1,000,000 g / mol; more preferably still from 20,000 to 500,000 g / mol.

7. A method according to any one of the preceding claims, characterized in that the total content of chitosan compound of formula (P) in composition T is in the range of 0.001% to 30% by weight, preferably 0.001% to 20% by weight, more preferably 0.005% to 10% by weight, even more preferably 0.01% to 5% by weight, better 0.01% to 2% by weight, relative to the total weight of composition T.

8. A process according to any one of the preceding claims, characterized in that the pH of the composition T is less than 6, more preferably less than or equal to 5, even more preferably is between 3 and 5.

9. A method according to any one of the preceding claims, characterized in that composition T comprises water; preferably in a total content in the range of 1% to 90% by weight, more preferably 30% to 80% by weight, more preferably 35% to 70% by weight, and even more preferably 40% to 60% by weight, relative to the total weight of composition T.

10. A process according to any one of the preceding claims, characterized in that the composition T further comprises one or more organic solvents.

11. A process according to any one of the preceding claims, characterized in that composition T is free of coloring agent.

12. A method according to any one of the preceding claims, for the protection of the artificial color of keratin fibers and / or for shaping keratin fibers, preferably in a high humidity environment.

13. Use of one or more chitosan compounds (P) or of a composition T comprising them as defined in claims 1 to 11, to protect keratin fibers from moisture, preferably to limit the formation of frizz and / or the increase in hair volume in a high humidity environment.

14. Use of one or more chitosan compounds (P) or of a composition T comprising them as defined in claims 1 to 11, to protect the artificial color of keratin fibers, preferably to increase the resistance of the artificial color to shampooing.