Process for the cosmetic treatment of keratin materials comprising at least the application of at least one zinc salt and at least one alkaline agent

Abstract

TITLE: Process for the cosmetic treatment of keratin materials comprising at least the application of at least one zinc salt and at least one alkaline agent The present invention relates to a process for the cosmetic treatment of keratin materials, in particular keratin fibers, in particular human keratin fibers such as hair, nails and / or skin, comprising at least the application on said keratin materials of at least one zinc salt and at least one alkaline agent.

Description

Title of the invention: Process for the cosmetic treatment of keratin materials comprising at least the application of at least one zinc salt and at least one alkaline agent

[0001] The present invention relates to a process for the cosmetic treatment of keratin materials, in particular keratin fibres, in particular human keratin fibres such as hair, nails and / or skin, comprising at least the use on said keratin materials of at least one zinc salt and at least one alkaline agent.

[0002] The structure of keratin fibers is generally made up of the following three concentric layers: the medulla (or medullary canal) constituting the central part of the fiber; the cuticle, representing the outermost layer of the fiber, formed of highly keratinized, non-pigmented cells and whose surface is made up of horny plates in the form of scales nested within each other; the cortex, corresponding to an intermediate zone between the medulla and the cuticle, which is the seat of pigmentation and provides the keratin fibers with their physical and mechanical properties, for example their flexibility, elasticity and / or strength. The cuticle thus has a surface that is sufficiently solid to protect the internal structure of the fiber.

[0003] However, external atmospheric agents such as pollution and bad weather, as well as mechanical or chemical treatments, or certain routines, such as brushing, combing, dyeing, bleaching, perming, straightening and / or repeated washing, can in the long run damage keratin fibers, in particular certain slightly more fragile areas of the cuticle.

[0004] Indeed, the edge of the cuticle scales can in particular wear more easily under the effect of friction induced by atmospheric agents and / or successive mechanical and / or chemical treatments which can thus strip the surface of the fibers in places, making the internal structure, in particular the cortex, more vulnerable to external attacks.

[0005] The fibers then have mechanical properties inferior to natural fibers. The hair becomes brittle and less resistant to external attacks and / or mechanical and / or chemical treatments.

[0006] Thus, to overcome these drawbacks, it is usual to use hair care compositions capable of forming a coating intended to protect the entire surface of the keratin fibers from external aggressions.

[0007] However, even if such compositions can provide cos- satisfactory properties to keratin fibers, the latter generally have the disadvantage of forming coatings which still too often remain sticky, causing numerous discomfort problems and are not sufficiently resistant, particularly to water and / or shampoos.

[0008] Furthermore, it is also usual to use compositions capable of forming a protective coating over the entire surface of the nails and / or the skin in order to protect the fragile areas, in particular the outermost area(s), of the nails and / or the skin, which may be subject to external aggression.

[0009] In the same way as previously, such coatings thus formed on the entire surface of the nails and / or the skin have the disadvantage of being too sticky and can pose problems of water resistance.

[0010] Thus there is a real need to implement a method making it possible to effectively protect the fragile area(s) of keratin materials, preferably skin, nails and / or keratin fibers, in particular human keratin fibers such as hair, in particular by satisfactorily protecting the edge of the scales of the surface of the keratin fibers and / or the fragile area(s) of skin, without inducing the disadvantages mentioned above, that is to say while minimizing the problems of discomfort and hold, for example in relation to water and / or shampoos.

[0011] The present invention therefore relates in particular to a process for the cosmetic treatment of keratin materials, in particular keratin fibres, in particular human keratin fibres such as hair, nails and / or skin, comprising at least the use on said keratin materials of at least one zinc salt and at least one alkaline agent.

[0012] The method according to the invention thus makes it possible to achieve the objectives as described above, that is to say that it leads to the formation of a coating making it possible to specifically and effectively protect the fragile area(s) of the keratin materials, in particular the keratin fibers, the nails and / or the skin, without however covering the entire surface of the keratin materials.

[0013] In other words, the method according to the invention makes it possible to effectively target the fragile area(s) of the keratin materials, for example the edge of the scales of the keratin fibers and / or the fragile areas of skin, without however leading to a deposit covering the entire surface of the keratin materials.

[0014] In other words, the method according to the invention leads to the formation of a deposit or coating concentrated on the fragile zone(s) of the treated keratin materials.

[0015] The deposits or coatings thus formed on the fragile area(s) of the keratin materials Uniques have good resistance to external aggressions, such as water, oils, especially food oils, sweat, sebum and / or shampoos, ensuring they last over time.

[0016] Furthermore, the coatings or deposits formed do not stick and transfer little, if at all, which makes it possible to minimize problems of discomfort after application.

[0017] Advantageously, when the method is carried out on keratin fibers, the coating thus formed makes it possible to effectively protect the fragile area(s) of the keratin fibers by forming on said area(s) a coating resistant to external agents, to mechanical and / or chemical treatments and resistant to water and / or shampoos as well as to fatty substances such as sebum.

[0018] The method according to the invention leads in particular to a coating resistant to abrasion and resistant to water and / or shampoos.

[0019] In particular, the method according to the invention leads in particular to resistant and persistent deposits concentrated on the edge of the scales of the surface of keratin fibers, in particular human keratin fibers such as hair.

[0020] The method according to the invention also results in a coating that is non-sticky on the skin and resistant to abrasion, in particular to repeated dry rubbing.

[0021] For the purposes of the present invention, the term "fragile zone of keratin materials" means one or more zones located on the outermost surface of the keratin materials and likely to be affected by external atmospheric agents and / or mechanical and / or chemical treatments.

[0022] By "fragile zone of the keratin fibers" is meant, within the meaning of the present invention, one or more zones located on the external surface of the keratin fibers, in particular on the cuticle surface, thus protecting the internal structure of the keratin fibers, preferably the cortex, and likely to be affected by external atmospheric agents and / or mechanical and / or chemical treatments.

[0023] Preferably, the fragile area(s) of the keratin fibers is or are the edge(s) of the scales of the keratin fibers, in particular human keratin fibers such as hair.

[0024] For the purposes of the present invention, the term "fragile skin zone" means one or more zones located on the external surface of the skin, in particular the papillary dermis, and likely to be affected by external atmospheric agents and / or friction.

[0025] Other objects, characteristics, aspects and advantages of the invention will appear even more clearly on reading the description and the example which follows.

[0026] In what follows, and unless otherwise indicated, the limits of a domain of values are included in this domain, in particular in the expressions “included between” and “ranging from ... to ...”.

[0027] Furthermore, the expression “at least one” used in the present description is equivalent to the expression “one or more”.

[0028] Similarly, the expression "at least" used in the present description is equivalent to the expression "greater than or equal to". Zinc salt(s)

[0029] As indicated above, the process according to the invention uses one or more zinc salts on the keratin materials.

[0030] The zinc salt(s) may be organic or inorganic zinc salts.

[0031] For the purposes of the present invention, zinc salts are understood to mean the hydrated or No.

[0032] According to a particular embodiment of the invention, the zinc salt(s) are chosen from Zn(NO3)2 (zinc nitrate), zinc halides such as ZnCl2 (zinc chloride), ZnBr2 (zinc bromide), Znl2 (zinc iodide), Zn(C104)2 (zinc perchlorate), ZnSO4 (zinc sulfate), Zn3(PO4)2 (zinc phosphate), zinc (poly)(hydroxy)(Ci-C2o)alkyl(poly)carboxylates such as (Zn(CH3COO) (zinc acetate), Zn3(C6H5O7)2 (zinc citrate), Zn(C3H5O3)2 (zinc lactate), C12H22O i4Zn (zinc gluconate), C24H46O4Zn (zinc laurate), C28H54O4Zn (myristate zinc), C32H62O4Zn (zinc palmitate), Zinc (poly)amino(Ci-C20)alkyl(poly)carboxylate such as C4H8N2O4Zn (zinc glycinate), Zinc (Ci-C4)(alkyl)acrylate such as Zn(CH2C(CH3)CO2)2 (zinc methacrylate), Zn(CH2CHCO2)2 (zinc acrylate), Zinc (Ci-C6)alkoxide such as Zn(OCH2CH2CH3)2 (zinc propoxide),Zinc (Ci-C4)alkyl(thio)carbonyl(Ci-C4)alkyl(thio)carbonyl(Ci-C4)alkyl such as Zn(Ci0H i4O7) (zinc acetylacetonate), Zn(C7Hi2NO3S)2 (zinc acetylmethionate), Zn(C4H6 NO4)2 (zinc aspartate), ZnCO3(zinc carbonate), Zn5(CH3O6)2 (zinc carbonate hydroxide), zinc coceth sulfate, C4H8N2O4Zn (zinc glycinate), C6oHQ008Zn (zinc glycyrrhetinate), Zinc hydrolyzed collagen, ZnO (zinc oxide), Zinc PCA (Zinc salt of pyrrolidone carboxylic acid), Zn(C6H5O4S)2 (zinc phenolsulfonate), Zn(C5H4NOS)2 (zinc pyrithione), C36H66O6Zn (zinc ricinoleate), Ci4Hio06Zn (zinc salicylate), C36H70O4Zn (zinc stearate), ZnS (zinc sulfide), Zinc (poly)(hydroxy)(C2-C20)alkenyl(poly)carboxylate such as C22H38O4Zn (zinc undecylenate), ZINC DNA (zinc salt of deoxyribonucleic acid), and mixtures thereof.

[0033] Preferably, the zinc salt(s) are inorganic zinc salts. In other words, the zinc salt(s) are preferentially chosen from mineral acid zinc salts.

[0034] More preferably, the zinc salt(s) are chosen from zinc halides such as zinc chloride, zinc nitrate, and mixtures thereof, even more preferably preferably zinc halides such as zinc chloride.

[0035] The zinc salt(s) may be formulated in a composition in a content ranging from 0.1 to 20% by weight, preferably from 0.5 to 10% by weight, more preferably from 1 to 6% by weight, relative to the total weight of said composition. Alkaline agent(s)

[0036] As indicated above, the process according to the invention also uses one or more alkaline agents on the keratin materials.

[0037] The alkaline agent(s) may be chosen from mineral, organic or hybrid alkaline agents.

[0038] Preferably, the alkaline agent(s) are organic alkaline agents.

[0039] For the purposes of the present invention, the terms “alkaline agent” or “alkalizing agent” are used interchangeably.

[0040] The mineral alkalizing agent(s) are preferably chosen from ammonia, alkali carbonates or bicarbonates such as sodium (hydrogen)carbonate and potassium (hydrogen)carbonate, alkali or alkaline earth metal phosphates such as sodium phosphates or potassium phosphates, sodium or potassium hydroxides, alkali or alkaline earth metal silicates or metasilicates such as sodium metasilicate and mixtures thereof.

[0041] The organic alkalizing agent(s) are preferably chosen from ammonia, alkanolamines, amino acids, organic amines other than alkanolamines, oxyethylenated and / or oxypropylenated ethylenediamines, 1,3 diaminopropane, spermine, spermidine and mixtures thereof.

[0042] By alkanolamine is meant an organic amine comprising a primary, secondary or tertiary amine function, and one or more linear or branched C1-C8 alkyl groups carrying one or more hydroxyl radicals.

[0043] Particularly suitable for carrying out the invention are organic amines chosen from alkanolamines such as mono-, di- or tri-alkanolamines, comprising one to three hydroxyalkyl radicals, identical or not, in C1-C4.

[0044] In particular, the alkanolamine(s) are chosen from monoethanolamine (MEA), diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, N,N-dimethylethanolamine, 2-amino-2-methyl-1-propanol, triisopropanolamine, 2-amino-2-methyl-1,3-propanediol, 3-amino-1,2-propanediol, 3-dimethylamino-1,2-propanediol, tris-hydroxymethylaminomethane and mixtures thereof.

[0045] Advantageously, the amino acids are basic amino acids comprising an additional amine function. Such basic amino acids are preferably chosen from histidine, lysine, arginine, omithine, citrulline.

[0046] The organic amine may also be chosen from heterocyclic organic amines. In addition to histidine already mentioned in the amino acids, mention may in particular be made of pyridine, piperidine, imidazole, triazole, tetrazole, benzimidazole. The organic amine may also be chosen from amino acid dipeptides. As amino acid dipeptides which may be used in the present invention, mention may in particular be made of carnosine, anserine and balenine. The organic amine may also be chosen from compounds comprising a guanidine function. As amines of this type other than arginine which may be used in the present invention, mention may in particular be made of creatine, creatinine, 1,1-dimethylguanidine, 1,1-diethylguanidine, glycocyamine, metformin, agmatine, n-amidinoalanine, 3-guanidinopropionic acid, 4-guanidinobutyric acid and 2-([amino(imino)methyl]amino)ethane-1-sulfonic acid.)

[0047] As hybrid compounds, it is possible in particular to use guanidine carbonate or monoethanolamine hydrochloride.

[0048] The alkaline agent(s) useful according to the invention is (are) preferably chosen from ammonia, alkanolamines such as monoethanolamine, diethanolamine, triethanolamine; ammonia, carbonates or bicarbonates such as sodium (hydrogen)carbonate and potassium (hydrogen)carbonates, silicates or metasilicates of alkali or alkaline earth metals such as sodium metasilicate, and mixtures thereof, more preferably from ammonia and alkanolamines, better still from alkanolamines, better still from the alkaline agent is monoethanolamine.

[0049] The alkaline agent(s) may be formulated in a composition in a content ranging from 0.1 to 20% by weight, preferably from 1 to 15% by weight, more preferably from 2 to 12% by weight, relative to the total weight of said composition. Process

[0050] As indicated above, the method according to the invention uses on keratin materials, preferably skin, nails and / or keratin fibers, in particular human keratin fibers such as hair, at least one zinc salt, as defined above, and at least one alkaline agent, as defined above.

[0051] Preferably, the keratin materials are treated with one or more compositions comprising, taken together or separately, in said composition(s), one or more zinc salts and one or more alkaline agents.

[0052] The zinc salt(s) and the alkaline agent(s) may be formulated in the same composition or in separate compositions.

[0053] Preferably, the zinc salt(s) and the alkaline agent(s) may be formulated in separate compositions.

[0054] Preferably, the method according to the invention comprises at least the application on the keratin materials of at least one composition A comprising one or more zinc salts, as defined above, and of at least one composition B comprising one or more alkaline agents, as defined above.

[0055] Composition A and composition B are distinct.

[0056] The zinc salt(s) may be formulated in composition A in a content ranging from 0.1 to 20% by weight, preferably from 0.5 to 10% by weight, more preferably from 1 to 6% by weight, relative to the total weight of said composition A.

[0057] The alkaline agent(s) may be formulated in composition B in a content ranging from 0.1 to 20% by weight, preferably from 0.5 to 10% by weight, more preferably from 1 to 4% by weight, relative to the total weight of said composition B.

[0058] Compositions A and B may contain one or more additives.

[0059] The composition according to the invention may thus further comprise one or more additives chosen from the group consisting of salts; emollients; moisturizers; perfumes; peptizers; vitamins; preservatives; anionic, cationic, non-ionic and amphoteric polymers, non-ionic, anionic, cationic or amphoteric surfactants, preferably cationic surfactants, and silicones.

[0060] A person skilled in the art will take care to choose any additives and their quantity so that they do not harm the cosmetic properties of the composition of the present invention.

[0061] These additives may be present in the composition according to the invention in an amount ranging from 0 to 20% by weight relative to the total weight of the composition.

[0062] Preferably, the method according to the invention comprises at least the application to the keratin materials of at least one composition A comprising one or more inorganic zinc salts of zinc, and of at least one composition B comprising one or more organic alkaline agents.

[0063] More preferably, the method according to the invention comprises at least the application to keratin materials: i) at least one composition A comprising one or more zinc salts chosen from zinc mineral acid salts, preferably chosen from zinc chloride, zinc nitrate, and mixtures thereof, even more preferably zinc chloride; ii) at least one composition B comprising one or more organic alkaline agents, in particular chosen from ammonia and alkanolamines.

[0064] The method according to the invention can be carried out on dry or wet keratin materials.

[0065] Preferably, the method is carried out on the skin and / or keratin fibers, in particular human keratin fibers such as hair, in particular the skin or keratin fibers.

[0066] The keratin fibers are preferably human keratin fibers such as hair.

[0067] Keratin fibers may or may not be sensitized.

[0068] Preferably, the keratin fibers are sensitized, more preferably by at least one permanent deformation process, for example a straightening or perming process, or at least one coloring and / or bleaching process, in particular bleaching.

[0069] More preferably, the keratin fibers are sensitized by at least one bleaching process.

[0070] Preferably, the method is a method for cosmetic treatment of the skin and / or hair, in particular the skin or hair.

[0071] Preferably, the step of applying composition A comprising one or more zinc salts, as defined above, includes a setting time ranging from 10 seconds to 1 hour, preferably from 30 seconds to 45 minutes, and more preferably from 1 minute to 40 minutes.

[0072] Preferably, the method according to the invention comprises at least one rinsing between the application of composition A and the application of composition B.

[0073] More preferably, the rinsing step between the application of composition A and the application of composition B is a water rinsing step.

[0074] According to a particular embodiment of the invention, the rinsing step is carried out with an aqueous composition comprising one or more additives as defined above. According to an advantageous embodiment, the rinsing step is carried out with water, in particular tap water, and without additives.

[0075] Preferably, composition A is applied before composition B.

[0076] Advantageously, the application bath ratio of composition A and composition B is between 0.5 and 20 grams of composition A or composition B per gram of keratin fibers.

[0077] Preferably, the step of applying composition B comprising one or more zinc salts, as defined above, includes a setting time ranging from 10 seconds to 1 hour, preferably from 30 seconds to 45 minutes, and more preferably from 1 minute to 40 minutes.

[0078] Preferably, the method according to the invention comprises at least one rinsing, preferably with water, after the application of composition B.

[0079] Advantageously, the method according to the invention is a method for forming a coating on the fragile area(s) of keratin materials, preferably skin and / or keratin fibers, in particular human keratin fibers such as hair.

[0080] Still advantageously, the method according to the invention is a training method

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[0092] of a coating on the edge of the hair scales. The following examples serve to illustrate the invention without, however, being limiting in nature. Examples 1. Compositions implemented The following compositions A and B were prepared from the ingredients, the quantities of which are indicated in percentage by weight, listed in Tables 1 and 2 below: 1. Operating mode Composition A is applied to strands of bleached hair and left on for 30 minutes. Then apply composition B to the strands and leave on for 10 minutes. Rinse the hair strands ten times with water. 1. Results The morphology of the strands of bleached hair treated by the process according to the invention and that of strands of bleached hair, from the same batch, untreated are analyzed by scanning electron microscopy (SEM). Morphological analysis of untreated bleached hair strands shows that the strands have a regular and homogeneous surface with well-defined scale edges. The morphological analysis of the locks of bleached hair treated by the process according to the invention shows that the locks have a regular and homogeneous surface and that a zinc coating has formed mainly on the edge of the hair scale without altering their definition (or their design). [Fig.l] shows a scanning electron microscopy (SEM) image of a strand of bleached hair treated by the method according to the invention. In this figure, we see that the strand has a regular and homogeneous surface and that a zinc coating has formed mainly on the edge of the hair scales without altering their definition.

[0093] [Fig.2] corresponds to an enlargement of the image described in [Fig.l] which shows that the zinc coating has indeed been deposited on the edge of the hair scales.

[0094] [Fig. 3] shows a scanning electron microscopy (SEM) image of a strand of untreated bleached hair. In this figure, it can be seen that the edges of the scales are well defined and are not covered. EXAMPLE 2: Compositions implemented

[0095] Composition A corresponds to the composition described in Table 1.

[0096] The following composition B2 was prepared from the ingredients, the quantities of which are indicated as a percentage by weight, listed in Table 3 below:

[0097] [Tables3] Composition B NH4OH Monoethanolamine 5% 5% Water Qsp 100 1. Operating mode

[0098] Composition A is applied to strands of natural hair and left on for 10 minutes.

[0099] Composition B is then applied to the strands and left to act for 10 minutes.

[0100] Rinse the locks of hair ten times with water. 1. Results

[0101] The morphology of the strands of natural hair treated by the process according to the invention and that of strands of natural hair, from the same batch, untreated are analyzed by scanning electron microscopy (SEM).

[0102] Morphological analysis of the strands of untreated natural hair shows that the strands have a regular and homogeneous surface with well-defined scale edges.

[0103] The morphological analysis of the locks of natural hair treated by the process according to the invention shows that the locks have a regular and homogeneous surface and that a zinc coating has formed mainly on the edge of the hair scale without altering their definition (or their design).

Claims

Claims

1. Process for the cosmetic treatment of keratin materials, comprising at least the use on said keratin materials of at least one zinc salt and at least one alkaline agent.

2. Method according to claim 1, characterized in that it comprises at least the application to said keratin materials of one or more compositions comprising, taken together or separately, in said composition(s), one or more zinc salts and one or more alkaline agents.

3. Method according to claim 1 or 2, characterized in that it comprises at least the application to said keratin materials: i) of at least one composition A comprising one or more zinc salts, and ii) of at least one composition B comprising one or more alkaline agents.

4. Method according to any one of the preceding claims, characterized in that the zinc salt(s) included in composition A are chosen from organic zinc salts, inorganic zinc salts and their mixtures, preferably from inorganic zinc salts.

5. Process according to any one of the preceding claims, characterized in that the zinc salt(s) are chosen from Zn(NO3)2 (zinc nitrate), zinc halides such as ZnCl2 (zinc chloride), ZnBr2 (zinc bromide), Znl2 (zinc iodide), Zn(C104)2 (zinc perchlorate), ZnSO4 (zinc sulfate), Zn3(PO4)2 (zinc phosphate), zinc (poly)(hydroxy)(Ci-C20)alkyl(poly)carboxylates such as (Zn(CH3COO) (zinc acetate), Zn3(C6H5O7)2 (zinc citrate), Zn(C3H5O3)2 (zinc lactate), Ci2H220i4Zn (zinc gluconate), C24H46O 4Zn (zinc laurate), C28H54O4Zn (zinc myristate), C32H62O4Zn (zinc palmitate), Zinc (poly)amino(Ci-C2o)alkyl(poly)carboxylate such as C4HgN2O4Zn (zinc glycinate), Zinc (CrC4)(alkyl)acrylate such as Zn(CH2C(CH3)CO2)2 (zinc methacrylate), Zn(CH2 CHCO2)2 (zinc acrylate), Zinc (Ci-C6)alkoxide such as Zn(OCH2CH2CH3)2 (zinc propoxide),Zinc (CrC4)alkyl(thio)carbonyl(Ci-C4)alkyl(thio)carbonyl(Ci-C4)alkyl such as Zn(Ci0Hi4O7) (zinc acetylacetonate), Zn(C7Hi2NO3S)2 (zinc acetylmethionate), Zn(C4H6NO4)2 (zinc aspartate), ZnCO3, (zinc carbonate), Zn5(CH3O6)2 (zinc carbonate hydroxide), zinc coceth sulfate (Zinc coceth sulfate), C4H8N2O4Zn (zinc glycinate), C6oHQ008Zn (zinc glycyrrhetinate), Zinc hydrolyzed collagen, ZnO (zinc oxide), Zinc PCA (Zinc salt of pyrrolidone-carboxylic acid), Zn(C6H5O4S)2 (zinc phenolsulfonate), Zn(C5H4NOS)2 (zinc pyrithione), C36H66O6Zn (zinc ricinoleate), C14Hi0O6Zn (zinc salicylate), C36H7oC)4Zn (zinc stearate), ZnS (zinc sulfide), Zinc (poly)(hydroxy)(C2-C20)alkenyl(poly)carboxylate such as C22H 38O4Zn (zinc undecylenate), ZINC DNA (zinc salt of deoxyribonucleic acid), and mixtures thereof; preferably, the zinc salt(s) are inorganic zinc salts.

6. Method according to any one of the preceding claims, characterized in that the zinc salt(s) are chosen from zinc halides such as zinc chloride, zinc nitrate and their mixture, preferentially chosen from zinc halides such as zinc chloride.

7. Process according to any one of claims 3 to 6, characterized in that the total content of the zinc salt(s) included in composition A ranges from 0.1 to 20% by weight, preferably from 0.5 to 10% by weight, more preferably from 1 to 6% by weight, relative to the total weight of composition A.

8. Process according to any one of the preceding claims, characterized in that the alkaline agent(s) is(are) chosen from alkanolamines such as monoethanolamine, diethanolamine, triethanolamine; ammonia, carbonates or bicarbonates such as sodium (hydrogen)carbonate and potassium (hydrogen)carbonate, silicates or metasilicates of alkali or alkaline earth metals such as sodium metasilicate and mixtures thereof, more preferably from ammonia, alkanolamines, silicates or metasilicates of alkali or alkaline earth metals, better still from alkanolamines and silicates or metasilicates of alkali or alkaline earth metals, better still from monoethanolamine and sodium metasilicate.

9. Process according to any one of claims 3 to 8, characterized in that the total content of the alkaline agent(s) included in composition B varies from 0.1 to 20% by weight, preferably from 0.5 to 10% by weight, more preferably from 1 to 6% by weight, relative to the total weight of composition B.

10. Method according to any one of claims 3 to 9, characterized in that it comprises at least one rinsing, preferably with water, between the application of composition A and the application of composition B.

11. Method according to any one of claims 3 to 10, characterized in that composition A is applied before composition B.

12. Method according to any one of the preceding claims, characterized in that said method is carried out on one or more fragile areas of the keratin materials.

13. Method according to any one of claims 3 to 12, characterized in that the application bath ratio of composition A and composition B is between 0.5 and 20 grams of composition A or composition B per gram of keratin fibers.

14. Method according to any one of the preceding claims, characterized in that said method is carried out on keratin fibers, in particular human keratin fibers such as hair.

15. Method according to any one of claims 1 to 13, characterized in that said method is carried out on nails and / or skin.

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