Method for treating keratin fibres using specific divalent or trivalent fatty acid salt and composition comprising said salt

Abstract

The present invention relates to a process for treating keratin fibres with a specific divalent or trivalent fatty acid salt, and to a composition comprising said salt.

Description

Field of the Invention

[0001] The present invention relates to a method for treating keratin fibers using specific divalent or trivalent fatty acid salts, and to a composition comprising said salts. Background of the Invention

[0002] Due to their nature, certain hair types are more sensitive to humidity and may thus have a tendency to form curls, which can lead to an increase in the volume of the entire head of hair. These hair types are particularly difficult to style in humid environments.

[0003] To remedy this, it is common practice to use hair compositions based on silicone starting materials, which may make the hair look greasy and feel heavy; or hair compositions based on oils, the conditioning effect of which may tend to disappear rapidly over time. In addition, consumers are increasingly looking for natural products.

[0004] Therefore, there is a real need to develop a hair treatment method that can remedy these drawbacks and, notably, is capable of permanently limiting the formation of curls and / or the increase in volume of the entire head of hair in a humid environment and facilitating styling of the hair in a humid environment.

[0005] The Applicant has surprisingly found that all or some of these objectives can be achieved by the method according to the invention. Summary of the Invention

[0006] According to a first aspect, the subject of the present invention is a method for treating keratin fibers, which method comprises the following step i) or step i'):

[0007] i) applying to the keratin fibers, at an acidic pH, a composition (A) comprising a) one or more divalent or trivalent fatty acid salts selected from compounds of formula (I), their isomers, their solvates such as hydrates, and mixtures thereof:

[0008]

[0009] In formula (I):

[0010] ■ R represents a straight-chain or branched, saturated or unsaturated hydrocarbon-based group containing from 7 to 29 carbon atoms, which hydrocarbon-based group is optionally substituted by one or more identical or different groups selected from: -COO - or -OH;

[0011] ■ X represents an alkaline earth metal, a transition metal, a post-transition metal or a lanthanide element;

[0012] ■ m represents a stoichiometric coefficient chosen to ensure the electrical neutrality of the compound of formula (I);

[0013] ■ n represents an integer equal to 2 or 3;

[0014] i’) applying composition (B) to the keratin fibers at acidic pH, the composition comprising:

[0015] a’) one or more fatty acids selected from compounds of formula (II), their isomers, their solvates such as hydrates, and mixtures thereof:

[0016]

[0017] In formula (II), R 1 represents a straight-chain or branched, saturated or unsaturated hydrocarbon-based group containing from 7 to 29 carbon atoms, the hydrocarbon-based group being optionally substituted by one or more identical or different groups selected from: -COOH - or -OH; and

[0018] b’) one or more metal salts selected from inorganic or organic salts of alkaline earth metals, transition metals, post-transition metals, lanthanides, solvates such as hydrates of these salts, and mixtures thereof.

[0019] According to a second aspect, the subject of the invention is composition (A) or (B) as previously defined.

[0020] According to a third aspect, the subject of the invention is the use of one or more divalent or trivalent fatty acid salts a) as previously defined or composition (A) as previously defined for protecting keratin fibers against the effects of moisture, preferably for limiting the formation of overall hair curl and / or the increase in volume in a humid environment.

[0021] According to a fourth aspect, the subject of the invention is the use of a combination of one or more fatty acids a’) as previously defined with one or more metal salts b’) as previously defined or composition (B) as previously defined for protecting keratin fibers against the effects of moisture, preferably for limiting the formation of overall hair curl and / or the increase in volume in a humid environment. Detailed embodiments

[0022] For the purposes of the present invention and unless otherwise indicated:

[0023] ■ The term "keratin fibers" means fibers of human or animal origin, such as hair, body hair, eyelashes, eyebrows, wool, mohair, cashmere or fur. According to the invention, the keratin fibers are preferably human keratin fibers, more preferably hair.

[0024] ■ The term "metal salt" means a salt notably obtained by the action of an acid on a metal.

[0025] The term "unsaturated hydrocarbon-based group" means a hydrocarbon-based group containing one or more conjugated or non-conjugated olefinic double bonds.

[0026] The term "alkyl" means a saturated straight-chain or branched hydrocarbon-based group containing 1 to 29 carbon atoms, preferably 1 to 25 carbon atoms, more preferably 1 to 21 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, butyl, n-pentyl, n-hexyl, n-decyl, n-undecyl, n-dodecyl, n-tetradecyl, n-hexadecyl or eicosyl.

[0027] The term "(C x -C y )alkyl" means an alkyl group containing x to y carbon atoms.

[0028] The term "isomer" means an optical, geometric or tautomeric isomer.

[0029] The terms "at least one / species" and "one / species or more / more species" are synonymous and can be used interchangeably.

[0030] Method for treating keratin fibers

[0031] According to a first aspect, the subject of the present invention is a method for treating keratin fibers as previously defined.

[0032] The Applicant has unexpectedly found that the method according to the invention makes it possible to permanently limit the formation of curls and / or the increase in volume of the whole head of hair in a humid environment and contributes to styling the hair in a humid environment.

[0033] First embodiment

[0034] According to a first embodiment, the method comprises step i) of applying composition (A) to the keratin fibers at an acidic pH, the composition comprising a) one or more divalent or trivalent fatty acid salts selected from compounds of formula (I), their isomers, their solvates such as hydrates, and mixtures thereof:

[0035]

[0036] In formula (I):

[0037] ■ R represents a straight-chain or branched, saturated or unsaturated hydrocarbon-based group containing 7 to 29 carbon atoms, the hydrocarbon-based group being optionally substituted by one or more identical or different groups selected from: -COO - or -OH;

[0038] ■ X represents an alkaline earth metal, a transition metal, a post-transition metal or a lanthanide element;

[0039] ■ m represents the stoichiometric coefficient selected to ensure the electrical neutrality of the compound of formula (I);

[0040] ■ n represents an integer equal to 2 or 3.

[0041] In formula (I) as previously defined, where R represents a straight-chain or branched, saturated or unsaturated hydrocarbon-based group containing from 7 to 29 carbon atoms and not substituted by one or more -COO - groups, m = n.

[0042] According to a preferred variant of this first embodiment, R represents a straight-chain or branched, saturated or unsaturated hydrocarbon-based group containing from 7 to 21 carbon atoms, preferably from 9 to 17 carbon atoms, which hydrocarbon-based group is optionally substituted by one or more identical or different groups selected from: -COO - or -OH.

[0043] According to a more preferred variant of this first embodiment, R represents a saturated straight-chain or branched hydrocarbon-based group containing from 7 to 29 carbon atoms, preferably from 7 to 21 carbon atoms, more preferably from 9 to 17 carbon atoms, which hydrocarbon-based group is optionally substituted by one or more identical or different groups selected from: -COO - or -OH.

[0044] According to an even more preferred variant of this first embodiment, R represents (C7-C 29 ) alkyl, preferably (C7-C 21 ) alkyl, more preferably (C9-C 17 ) alkyl.

[0045] According to a preferred variant of this first embodiment, X represents a metal selected from calcium, magnesium, barium, yttrium, manganese, zinc, bismuth, cerium or samarium, preferably selected from magnesium, yttrium, zinc, bismuth or cerium, more preferably selected from magnesium, yttrium, zinc or bismuth.

[0046] Salt a) is preferably selected from magnesium myristate, zinc myristate, yttrium myristate, cerium myristate, magnesium stearate, zinc stearate, yttrium stearate, bismuth neodecanoate, its isomers, its solvates such as hydrates and mixtures thereof, preferably selected from magnesium myristate, zinc stearate, bismuth neodecanoate, yttrium myristate, its isomers, its solvates such as hydrates and mixtures thereof.

[0047] Composition (A) comprises a total salt a) content which is preferably in the range of from 0.5% to 30% by weight, more preferably in the range of from 0.6% to 20% by weight, even more preferably in the range of from 0.8% to 10% by weight, based on the total weight of composition (A).

[0048] Second Embodiment

[0049] According to the second embodiment, the method comprises step i’) of applying composition (B) to the keratin fibers at acidic pH, the composition comprising:

[0050] a’) one or more fatty acids selected from compounds of formula (II), their isomers, their solvates such as hydrates and their mixtures:

[0051]

[0052] In formula (II), R 1 represents a straight-chain or branched, saturated or unsaturated hydrocarbon-based group comprising from 7 to 29 carbon atoms, the hydrocarbon-based group being optionally substituted by one or more identical or different groups selected from: -COOH or -OH; and

[0053] b’) one or more salts selected from inorganic or organic salts of alkaline earth metals, transition metals, post-transition metals, lanthanides, their solvates such as hydrates and their mixtures.

[0054] Mixing one or more fatty acids a’) with one or more metal salts b’) notably allows in-situ formation of one or more salts a) as previously defined.

[0055] Preferably, salt b’) is different from salt a) as previously defined.

[0056] According to a preferred variant of this second embodiment, R 1 represents a straight-chain or branched, saturated or unsaturated hydrocarbon-based group comprising from 7 to 21 carbon atoms, preferably from 9 to 17 carbon atoms, more preferably from 11 to 15 carbon atoms, the hydrocarbon-based group being optionally substituted by one or more identical or different groups selected from: -COOH or -OH.

[0057] According to a more preferred variant of this second embodiment, R 1 represents a saturated straight-chain or branched hydrocarbon-based group comprising from 7 to 29 carbon atoms, preferably from 7 to 21 carbon atoms, more preferably from 9 to 17 carbon atoms, even more preferably from 11 to 15 carbon atoms, the hydrocarbon-based group being optionally substituted by one or more identical or different groups selected from: -COOH or -OH.

[0058] According to an even more preferred variant of this second embodiment, R 1 represents (C7-C 29 ) alkyl, preferably (C7-C 21 ) alkyl, more preferably (C9-C 17 ) alkyl, even more preferably (C 11 -C15 ) alkyl group.

[0059] Fatty acid a') is preferably selected from myristic acid, stearic acid, neodecanoic acid, its solvates such as hydrates and mixtures thereof, more preferably selected from myristic acid, its solvates such as hydrates and mixtures thereof.

[0060] According to a preferred variant of this second embodiment, the salt b') is selected from compounds of formula (III) below, their isomers, their solvates such as hydrates and mixtures thereof:

[0061] X1 n+ q Y - (III)

[0062] In formula (III):

[0063] ■ X1 represents an alkaline earth metal, a transition metal, a post-transition metal or a lanthanide element, preferably selected from calcium, magnesium, barium, yttrium, manganese, zinc, bismuth, cerium or samarium, more preferably selected from magnesium, yttrium, zinc, bismuth or cerium, even more preferably selected from cerium or yttrium;

[0064] ■ n represents an integer equal to 2 or 3;

[0065] ■ Y - represents a monovalent or divalent organic or inorganic anion preferably containing 6 or fewer carbon atoms, preferably an inorganic anion;

[0066] ■ q represents a stoichiometric coefficient selected to ensure the electrical neutrality of the compound of formula (III).

[0067] According to a preferred variant of this second embodiment, the salt b') is selected from compounds of formula (III) below, their isomers, their solvates such as hydrates and mixtures thereof:

[0068] X1 n+ q Y - (III)

[0069] In formula (III):

[0070] ■ X1 represents an alkaline earth metal, a transition metal, a post-transition metal or a lanthanide element, preferably selected from calcium, magnesium, barium, yttrium, manganese, zinc, bismuth, cerium or samarium, more preferably selected from magnesium, yttrium, zinc, bismuth or cerium, even more preferably selected from cerium or yttrium;

[0071] ■ n represents an integer equal to 2 or 3;

[0072] ■ Y -represents an anion selected from the group consisting of acetate, acetylacetonate, oxalate, gluconate, carbonate, nitrate, sulfate or a halide such as chloride, preferably selected from the group consisting of carbonate, nitrate, sulfate or a halide such as chloride, more preferably selected from the group consisting of nitrate or a halide such as chloride;

[0073] · q represents the stoichiometric coefficient chosen to ensure the electroneutrality of the compound of formula (III).

[0074] The salt b') is preferably selected from cerium nitrate, cerium chloride, yttrium nitrate, yttrium chloride, solvates thereof such as hydrates and mixtures thereof, more preferably selected from cerium nitrate hexahydrate, cerium chloride hexahydrate, yttrium nitrate hexahydrate, yttrium chloride hexahydrate and mixtures thereof.

[0075] Composition (B) comprises a total fatty acid a') content preferably ranging from 1% to 20% by weight, more preferably ranging from 2% to 10% by weight relative to the total weight of composition (B).

[0076] Composition (B) comprises a content of total salts b') preferably ranging from 0.05% to 0.5% by weight, more preferably ranging from 0.1% to 0.25% by weight relative to the total weight of composition (B).

[0077] The weight ratio of the total amount of fatty acids a′) to the total amount of salts b′) present in composition (B) is preferably from 5 to 30, more preferably from 10 to 25.

[0078] Other characteristics of composition (A) or (B)

[0079] Composition (A) or (B) is a cosmetic composition, ie a composition comprising a cosmetically acceptable medium, ie a medium compatible with human keratin fibres.

[0080] Composition (A) or (B) may contain water, preferably in a total content ranging from 5% to 50% by weight, preferably ranging from 7% to 40% by weight relative to the total weight of composition (A) or (B).

[0081] The pH of composition (A) or (B) is acidic. The pH of composition (A) or (B) is preferably between 2 and 5. Preferably, the pH of composition (A) or (B) is equal to 2.

[0082] Composition (A) or (B) may comprise one or more organic solvents selected from linear or branched alkanes containing 8 to 18 carbon atoms, such as isododecane, tetradecane or isohexadecane, C2-C4 alcohols such as ethanol, ethers such as dioctyl ether, carbonates such as dicaprylyl carbonate or diethylhexyl carbonate, and mixtures thereof.

[0083] When they are present in composition (A), these organic solvents may be present in a content ranging from 20% to 99.9% by weight relative to the total weight of composition (A).

[0084] When they are present in composition (B), these organic solvents may be present in a content ranging from 50% to 95% by weight, preferably ranging from 60% to 95% by weight relative to the total weight of composition (B).

[0085] The pH of composition (A) or (B) can be adjusted using an organic or inorganic acid such as hydrochloric acid, sulfuric acid, citric acid, succinic acid, tartaric acid, lactic acid, toluenesulfonic acid, benzenesulfonic acid, phosphoric acid or acetic acid. Preferably, the pH of composition (A) or (B) is adjusted using hydrochloric acid.

[0086] Composition (A) or (B) may be in any presentation form conventionally used for hair care applications. In a non-limiting manner, composition (A) or (B) may be in the form of a lotion, cream, mousse, gel, spray or lacquer.

[0087] Preferably, composition (A) or (B) is used as a leave-on application.

[0088] Composition (A) or (B) can be packaged in a pump bottle or an aerosol container so that it can be applied in a vaporized (setting agent) form or in a mousse form. In these cases, composition (A) or (B) preferably comprises at least one propellant.

[0089] According to a preferred embodiment, composition (A) or (B) comprises a total content of colorants of less than 0.1% by weight, preferably less than 0.01% by weight, more preferably less than 0.001% by weight relative to the total weight of composition (A) or (B); even more preferably, composition (A) or (B) contains no colorants.

[0090] The term "colorant" means an oxidation dye, a direct dye or a pigment.

[0091] The term "oxidation dye" means an oxidation dye precursor selected from oxidation bases and couplers. Oxidation bases and couplers are colorless or slightly colored compounds which form colored substances via a condensation reaction in the presence of an oxidizing agent.

[0092] The term "direct dye" means natural and / or synthetic dyes other than oxidation dyes, including in the form of one or more extracts. These are colored compounds that will spread on the surface of the fiber. They can be ionic or nonionic, i.e. anionic, cationic, neutral or nonionic.

[0093] According to a preferred embodiment, composition (A) or (B) comprises a total content of silicone of less than 0.1% by weight, preferably less than 0.01% by weight, more preferably less than 0.001% by weight, relative to the total weight of composition (A) or (B); even more preferably, composition (A) or (B) is free of silicone.

[0094] According to a preferred embodiment, composition (A) or (B) comprises a total content of cationic polymer of less than 0.1% by weight, preferably less than 0.01% by weight, more preferably less than 0.001% by weight, relative to the total weight of composition (A) or (B); even more preferably, composition (A) or (B) is free of cationic polymer.

[0095] The term "cationic polymer" means any non-silicone polymer (not containing silicon atoms) containing cationic groups and / or groups that can be ionized into cationic groups and not containing any anionic groups and / or groups that can be ionized into anionic groups.

[0096] Composition (A) or (B) can be applied to dry or wet keratin fibers, preferably to wet keratin fibers.

[0097] The bath ratio range of composition (A) or (B) applied to keratin fibers can be from 0.1 to 10. The term "bath ratio" means the ratio between the total weight of composition (A) or (B) applied and the total weight of the keratin fibers to be treated.

[0098] The method can include at least one additional step selected from the following steps ii) and / or iii) after step i) or i'):

[0099] ii) A step of applying composition (A) or (B) to the keratin fibers, preferably for a period of at least 10 seconds, and the application step is optionally carried out under an airtight film of the wrap or plastic film type;

[0100] iii) A step of drying the keratin fibers in ambient air or using a heating device.

[0101] Preferably, the method includes additional steps ii) and iii) as described previously and carried out in this order.

[0102] The step of applying composition (A) or (B) can last from 10 seconds to 60 minutes, preferably from 30 seconds to 30 minutes.

[0103] The temperature range of the heating device can be from 45°C to 230°C, preferably from 45°C to 100°C, more preferably from 50°C to 80°C. A hair dryer, a heating hood, hair straighteners or a heated brush can be used as the heating device, for example.

[0104] The drying step iii) can also be drying with air or with a heating device (such as a hair dryer or a heating hood) in a temperature range of 50 °C to 80 °C, possibly followed by a straightening step (preferably with hair straighteners) in combination.

[0105] Step i) or i’) and optionally step ii) and / or iii) can be repeated as many times as needed, and each cycle of these steps can be spaced from the next by several minutes to several days or weeks. Different hair treatments of the present invention can be carried out between, before or after different application cycles.

[0106] Composition (A) or (B)

[0107] According to a second aspect, the subject matter of the present invention is composition (A) or (B) as previously defined. The pH of composition (A) or (B) is acidic.

[0108] Use

[0109] According to a third aspect, the subject matter of the present invention is the use of one or more divalent or trivalent fatty acid salts a) as previously defined or of composition (A) as previously defined for protecting keratin fibers against the action of moisture, preferably for limiting the formation of curls and / or the increase in volume of the entire head of hair in a humid environment.

[0110] According to a fourth aspect, the subject matter of the present invention is the use of a combination of one or more fatty acids a’) as previously defined with one or more salts b’) as previously defined or of composition (B) as previously defined for protecting keratin fibers against the action of moisture, preferably for limiting the formation of curls and / or the increase in volume of the entire head of hair in a humid environment.

[0111] Examples

[0112] The following examples provide a better understanding of the present invention, which is not restrictive in nature, however.

[0113] The following fatty acid salts a) were used in the examples:

[0114] [Table 1]

[0115]

[0116] Synthesis of compound a4

[0117] Compound a4 was synthesized according to the following procedure:

[0118] Procedure

[0119] 2.5 g (i.e., 0.01 mol) of sodium myristate (M = 250.35 g / mol) was placed in a 250 ml flask, and then 100 ml of absolute ethanol was added. The mixture was stirred until completely dissolved.

[0120] Then, 1.2 g (i.e., 0.0031 mol) of yttrium nitrate hexahydrate (M = 383.01 g / mol) was added in portions, and then the reaction mixture was kept stirred at room temperature for 12 hours. The precipitate formed was then filtered off on a sintered funnel and dried to constant weight under vacuum at 40 °C. Thus, 2.3 g of yttrium myristate (M = 771 g / mol) in the form of a white powder was obtained in 95% yield. The white solid was characterized by infrared spectroscopy measurement and elemental analysis.

[0121] Compositions A1 to A6, C, D1 to D4, B1 to B4, and also the following reference compositions R1 to R4 were prepared and used in the examples:

[0122] Compositions A1 to A6 according to the present invention

[0123] [Table 2]

[0124]

[0125] [Table 3]

[0126] Ingredient C Myristic acid 50.3 g (0.2202 mol) Ethanol 1L

[0127] [Table 4]

[0128]

[0129]

[0130] Compositions B1 to B4 according to the present invention

[0131] [Table 5]

[0132]

[0133] Reference compositions R1 to R4

[0134] [Table 6]

[0135]

[0136] Compositions A1 to A6, B1 to B4, and R1 to R4 were administered and evaluated according to the administration and evaluation protocol described below.

[0137] Administration and evaluation protocol

[0138] Apply 2.7 ml of each of compositions A1 to A6, B1 to B4 and R1 to R4 to different tresses of 2.7 g of Brazilian type IV hair for 30 seconds. Then place the tresses in an oven at 25 °C and 80% humidity at T0, and measure the volume and curl over time by measuring the width of the tresses at the middle height until T0 + 24H00.

[0139] Evaluation results

[0140] The measurement results of the width of the tresses at the middle height in cm are summarized in the following table:

[0141] [Table 7]

[0142]

[0143]

[0144] It can be seen that the width values of the tresses of the examples according to the invention are lower at the middle height compared to the examples using the reference composition.

[0145] Therefore, the method according to the invention makes it possible to limit the formation of curl and the increase in volume of the whole head of hair in a humid environment.

Claims

1. A method for treating keratin fibers, the method comprising the following step i) or Step i'): i) applying composition (A) to the keratin fibers at acidic pH, said composition comprising a) one or more divalent or trivalent fatty acid salts selected from compounds of formula (I) below, their isomers, their solvates such as hydrates, and mixtures thereof: In formula (I): ■R represents a straight-chain or branched-chain, saturated or unsaturated hydrocarbon-based group containing from 7 to 29 carbon atoms, said hydrocarbon-based group being optionally substituted by one or more identical or different groups selected from the following: -COO - or -OH; ■ X represents an alkaline earth metal, a transition metal, a post-transition metal or a lanthanide element; ■ m represents a stoichiometric coefficient chosen to ensure the electrical neutrality of the compound of formula (I); ■ n represents an integer equal to 2 or 3; i’) applying composition (B) to the keratin fibers at acidic pH, said composition comprising: a’) one or more fatty acids selected from compounds of formula (II) below, their isomers, their solvates such as hydrates, and mixtures thereof; In the formula (II), R 1 represents a straight-chain or branched-chain, saturated or unsaturated hydrocarbon-based group having 7 to 29 carbon atoms, said hydrocarbon-based group being optionally substituted by one or more identical or different groups selected from: -COOH - or -OH; and b’) one or more metal salts selected from inorganic or organic salts of alkaline earth metals, transition metals, post-transition metals, lanthanide elements, solvates such as hydrates of these salts, and mixtures thereof.

2. The method according to the preceding claim, wherein, The method comprises step i), and R represents a straight-chain or branched, saturated or unsaturated hydrocarbon-based group having from 7 to 21 carbon atoms, preferably from 9 to 17 carbon atoms, said hydrocarbon-based group being optionally substituted by one or more identical or different groups selected from: -COO - or -OH.

3. The method according to claim 1, wherein, The method comprises step i), and R represents a saturated straight-chain or branched hydrocarbon-based group having from 7 to 29 carbon atoms, preferably from 7 to 21 carbon atoms, more preferably from 9 to 17 carbon atoms, the hydrocarbon-based group being optionally substituted by one or more identical or different groups selected from: -COO - or -OH; preferably, R represents (C7-C 29 )alkyl, preferably (C7-C 21 )alkyl, more preferably (C9-C 17 )alkyl.

4. The method according to any one of the preceding claims, wherein, The method comprises step i), and X represents a metal selected from calcium, magnesium, barium, yttrium, manganese, zinc, bismuth, cerium or samarium, preferably selected from magnesium, yttrium, zinc, bismuth or cerium, more preferably selected from magnesium, yttrium, zinc or bismuth.

5. The method according to any one of the preceding claims, wherein, The method comprises step i), and the salt a) is preferably selected from magnesium myristate, zinc myristate, yttrium myristate, cerium myristate, magnesium stearate, zinc stearate, yttrium stearate, bismuth neodecanoate, their isomers, their solvates such as hydrates and mixtures thereof, preferably selected from magnesium myristate, zinc stearate, bismuth neodecanoate, yttrium myristate, their isomers, their solvates such as hydrates and mixtures thereof.

6. The method according to any one of the preceding claims, wherein, The method comprises step i), and composition (A) comprises a total content of salt a) in a range of from 0.5% to 30% by weight, preferably in a range of from 0.6% to 20% by weight, more preferably in a range of from 0.8% to 10% by weight, relative to the total weight of composition (A).

7. The method according to claim 1, wherein The method comprises step i'), and R 1 represents a straight-chain or branched, saturated or unsaturated hydrocarbon-based group having 7 to 21 carbon atoms, preferably 9 to 17 carbon atoms, more preferably 11 to 15 carbon atoms, said hydrocarbon-based group being optionally substituted by one or more identical or different groups selected from: -COOH or -OH.

8. The method according to claim 1, wherein The method includes step i’), and R 1 represents a saturated straight-chain or branched hydrocarbon-based group having 7 to 29 carbon atoms, preferably 7 to 21 carbon atoms, more preferably 9 to 17 carbon atoms, and even more preferably 11 to 15 carbon atoms, said hydrocarbon-based group being optionally substituted by one or more identical or different groups selected from: -COOH or -OH.

9. The method according to any one of claims 1, 7 or 8, wherein The method comprises step i’), and the fatty acid a’) is selected from myristic acid, stearic acid, neodecanoic acid, their solvates such as hydrates and mixtures thereof, preferably selected from myristic acid, its solvates such as hydrates and mixtures thereof.

10. The method according to any one of claims 1 or 7 to 9, wherein The method comprises step i’), and the salt b’) is selected from compounds of formula (III) below, their isomers, their solvates such as hydrates and mixtures thereof: X1 n+ q Y - (III) In formula (III): ■ X1 represents an alkaline earth metal, a transition metal, a post-transition metal or a lanthanide element, preferably selected from calcium, magnesium, barium, yttrium, manganese, zinc, bismuth, cerium or samarium, more preferably selected from magnesium, yttrium, zinc, bismuth or cerium, even more preferably selected from cerium or yttrium; ■ n represents an integer equal to 2 or 3; ■Y - represents a monovalent or divalent organic or inorganic anion preferably containing 6 or fewer carbon atoms, preferably an inorganic anion; ■ q represents a stoichiometric coefficient chosen to ensure the electrical neutrality of the compound of formula (III).

11. The method according to any one of claims 1 or 7 to 10, wherein, The method comprises step i’), and the salt b’) is selected from compounds of formula (III) below, their isomers, their solvates such as hydrates and mixtures thereof: X1 n+ q Y - (III) In formula (III): ■X1 represents an alkaline earth metal, a transition metal, a post-transition metal or a lanthanide element, preferably selected from calcium, magnesium, barium, yttrium, manganese, zinc, bismuth, cerium or samarium, more preferably selected from magnesium, yttrium, zinc, bismuth or cerium, even more preferably selected from cerium or yttrium; ■n represents an integer equal to 2 or 3; ■Y - represents an anion selected from the following: acetate, acetylacetonate, oxalate, gluconate, carbonate, nitrate, sulfate or a halide ion such as chloride ion, preferably selected from carbonate, nitrate, sulfate or a halide ion such as chloride ion, more preferably selected from nitrate or a halide ion such as chloride ion; ■q represents a stoichiometric coefficient selected to ensure the electrical neutrality of the compound of formula (III).

12. The method according to any one of claims 1 or 7 to 11, wherein The method comprises step i’), and the salt b’) is selected from cerium nitrate, cerium chloride, yttrium nitrate, yttrium chloride, their solvates such as hydrates and mixtures thereof, preferably selected from cerium nitrate hexahydrate, cerium chloride hexahydrate, yttrium nitrate hexahydrate, yttrium chloride hexahydrate and mixtures thereof.

13. The method according to any one of claims 1 or 7 to 12, wherein, The method comprises step i’), and the composition (B) comprises: - total fatty acids a’) in a content range of 1% to 20% by weight, preferably in a range of 2% to 10% by weight, relative to the total weight of the composition (B); and / or - total salt b’) in a content range of 0.05% to 0.5% by weight and preferably in a range of 0.1% to 0.25% by weight, relative to the total weight of the composition (B).

14. The method according to any one of claims 1 or 7 to 13, wherein, The weight ratio of the total amount of fatty acids a’) present in the composition (B) to the total amount of salt b’) is 5 to 30, more preferably 10 to 25.

15. The method according to any one of the preceding claims, wherein, The pH of the composition (A) or (B) is 2 to 5.

16. The method according to any one of the preceding claims, wherein, The composition (A) or (B) comprises one or more organic solvents selected from straight-chain or branched-chain alkanes having 8 to 18 carbon atoms such as isododecane, tetradecane or isohexadecane, C2-C4 alcohols such as ethanol, ethers such as dioctyl ether, carbonates such as dioctyl carbonate or diethylhexyl carbonate, and mixtures thereof.

17. The method according to any one of the preceding claims, wherein, The composition (A) or (B) is applied to dry or wet keratin fibers, preferably to wet keratin fibers.

18. The method according to the preceding claim, which comprises at least one additional step after step i) or i’), said at least one additional step being selected from the following steps ii) and / or iii): ii) a step of applying the composition (A) or (B) to the keratin fibers, preferably for a period of at least 10 seconds, said application step being optionally carried out under an airtight film of the wrapper or plastic film type; iii) a step of drying the keratin fibers in ambient air or using a heating device.

19. A composition (A) or (B) as defined in any one of claims 1 to 15.

20. Use of one or more divalent or trivalent fatty acid salts a) as defined in any one of claims 1 to 5 or of a composition (A) as defined in any one of claims 1 to 6, 15 or 16 for protecting keratin fibers against the action of moisture, preferably for the use of limiting the formation of overall hair curls and / or the increase in volume in a humid environment.

21. Use of a combination of one or more fatty acids a') as defined in any one of claims 1 or 7 to 9, with one or more metal salts b') as defined in any one of claims 1 or 10 to 12, or with the composition (B) as defined in any one of claims 1 or 7 to 16, for protecting keratin fibers against the effects of moisture, preferably for limiting the formation of curls and / or the increase in volume of the entire head of hair in a humid environment.

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