A process for treating and / or caring for keratinous fibers, combining a water-soluble silicate and an acidic compound

Abstract

A method for treating and / or caring for keratinous fibers, combining a water-soluble silicate and an acidic compound. The present invention relates to a method for treating and / or caring for keratinous fibers, preferably hair, comprising the steps of: i) applying to the keratinous fibers a first composition comprising at least one water-soluble silicate; and ii) applying to the keratinous fibers a second composition comprising at least one acidic compound, wherein the second composition has a pH value of 1 to 6. Figure for the abstract: None

Description

Title of the invention: Process for treating and / or caring for keratinous fibers, combining a water-soluble silicate and an acid compound Technical field

[0001] The present invention relates to a method for treating keratinous fibers, in particular a method for treating and / or caring for keratinous fibers, combining a water-soluble silicate and an acidic compound, to alleviate damage to the hair.

[0002] context of art

[0003] Water-soluble silicates, such as alkali silicates, are widely used in hair coloring and bleaching products to provide a high pH as well as to chelate metal ions.

[0004] For example, document WO 2021 / 009083 discloses a method for treating keratinous fibers, comprising the following successive steps: i) application to the keratinous fibers of a composition (A) comprising at least one water-soluble silicate; and ii) application to the keratinous fibers of a composition (B) comprising at least one compound (b) chosen from amino acids, oligopeptides, salts thereof, solvates thereof such as hydrates, and mixtures thereof.

[0005] However, there is a problem of hair damage when water-soluble silicates are applied to the hair. disclosure of the invention

[0006] An objective of the present invention is to provide a novel method for treating and / or caring for keratinous fibers, such as hair, which can mitigate damage to hair caused by water-soluble silicates, such as alkali silicates, and furthermore, which may be capable of improving the integrity of keratinous fibers.

[0007] The above objective of the present invention can be achieved by a method of coloring keratinous fibers, preferably hair, comprising the steps of:

[0008] i) applying to the keratinous fibers a first composition comprising at least one water-soluble silicate; and

[0009] ii) applying to the keratinous fibres a second composition comprising at least one acidic compound, in which the second composition has a pH value of 1 to 6.

[0010] The second composition may comprise amino acids and / or oligopeptides in an amount of less than 1% by weight, preferably less than 0.5% by weight, and more preferably less than 0.1% by weight, relative to the total amount of the second composition, or the second composition is free of amino acids and / or oligopeptides.

[0011] The water-soluble silicate may be selected from alkali or alkaline earth metal silicates and mixtures thereof, preferably from alkali metal silicates, such as sodium silicates, potassium silicates and mixtures thereof, and more preferably from sodium silicates.

[0012] The first composition may comprise the water-soluble silicate(s) in an amount of 0.05% by weight or more, preferably 0.1% by weight or more, more preferably 0.2% by weight or more, even more preferably 0.5% by weight or more, and especially 0.8% by weight or more; and / or may be 10% by weight or less, preferably 5% by weight or less, and more preferably 3% by weight or less, and even more preferably 2% by weight or less, based on the total weight of the first composition.

[0013] The acidic compound may be chosen from organic acids, preferably chosen from organic acids having one or more carboxylic acid groups and / or phosphonic groups.

[0014] The acidic compound may be chosen from hydroxy acids, preferably from α-hydroxy acids, and aliphatic monocarboxylic acids.

[0015] The acidic compound may be selected from glyoxylic acid, lactic acid, malic acid, citric acid, tartaric acid, mandelic acid, gluconic acid, phytic acid and a mixture thereof.

[0016] The second composition may comprise the acid compound(s) in an amount of 0.05% by weight or more, preferably 0.1% by weight or more, more preferably 0.2% by weight or more, even more preferably 0.5% by weight or more, and in particular 0.8% by weight or more; and / or may be 10% by weight or less, preferably 5% by weight or less, and more preferably 3% by weight or less, and even more preferably 2% by weight or less, relative to the total weight of the second composition.

[0017] The pH of the first composition may range from 8 to 13, preferably from 8 to 12.5, and more preferably from 8.5 to 12.5.

[0018] The pH value of the second composition may range from 1 to 5, and preferably from 1 to 4.

[0019] The method according to the present invention may further comprise a step of rinsing and / or washing the keratinous fibers between steps i) and ii).

[0020] Step ü) can be carried out directly after step i) of the method.

[0021] The present invention also relates to a kit for treating and / or caring for keratinous fibers, preferably hair, comprising:

[0022] a first compartment including the first composition comprising at least one water-soluble silicate, and

[0023] a second compartment including the second composition comprising at least one acidic compound, wherein the second composition has a pH value of 1 to 6.

[0024] The present invention also relates to a use of the second composition comprising at least one acidic compound, wherein the second composition has a pH value of 1 to 6, for mitigating or reducing damage caused by the water-soluble silicate included in the first composition to keratinous fibers, preferably hair. Brief description of the drawings

[0025] [Fig-1] [Fig.l] shows cross-sectional images of keratinous fibers treated according to (a) the reference, (b) comparative example 2, and (c) example 2, observed under fluorescence microscopy.

[0026] BEST MODE FOR CARRYING OUT THE INVENTION

[0027] After diligent research, the inventors surprisingly discovered that the method according to the present invention can mitigate the damage to hair caused by water-soluble silicates, such as alkali silicates, and even more, which may be able to improve an integrity of keratinous fibers, and thus made the invention.

[0028] Thus, one aspect of the present invention is a method for treating and / or caring for keratinous fibers, preferably hair, comprising the steps of:

[0029] i) applying to the keratinous fibers a first composition comprising at least one water-soluble silicate; and

[0030] ii) applying to the keratinous fibres a second composition comprising at least one acidic compound, in which the second composition has a pH value of 1 to 6.

[0031] Another aspect of the present invention is a kit that can be used for the method of the present invention above.

[0032] Hereinafter, the method and the kit according to the present invention will each be described in detail.

[0033] [Process]

[0034] The method according to the present invention is a method for treating and / or caring for keratinous fibers, preferably hair, comprising the steps of:

[0035] i) applying to the keratinous fibers a first composition comprising at least less than one water-soluble silicate; and

[0036] ii) applying to the keratinous fibres a second composition comprising at least one acidic compound, in which the second composition has a pH value of 1 to 6.

[0037] The method according to the present invention aims to treat, care for and / or condition keratinous fibers such as hair. By "keratinous fibers" is meant fibers of human or animal origin, such as hair, body hair, eyelashes, eyebrows, wool, angora, cashmere or fur. According to the present invention, the keratinous fibers are preferably human keratinous fibers, more preferably hair.

[0038] {Step i)}

[0039] Step i) is a step of applying to the keratinous fibers a first composition comprising at least one water-soluble silicate.

[0040] The first composition may take various forms, such as a solution, a gel, a lotion, a serum, a suspension, a dispersion, a fluid, a milk, a paste, a cream, an emulsion (in O / W or W / O form), or the like. It is preferable that the first composition according to the present invention is an aqueous solution.

[0041] The pH of the first composition may be adjusted to the desired value. It is preferable that the pH of the first composition of the present invention is from 8 to 13, preferably from 8 to 12.5, and more preferably from 8.5 to 12.5. The pH of the first composition may be adjusted to the desired value using alkaline agent(s) and / or acidic agent(s) commonly used in the field of cosmetics.

[0042] The first composition comprises at least one water-soluble silicate that dissolves in the first composition.

[0043] (Water soluble silicate)

[0044] By "water-soluble silicate" is meant a silicate whose solubility in water at ordinary room temperature (25°C) and atmospheric pressure (760 mmHg) is greater than 0.5% by weight, preferably greater than 1% by weight.

[0045] The water-soluble silicate is preferably selected from alkali or alkaline earth metal silicates, and mixtures thereof. More preferably, the water-soluble silicate is selected from alkali metal silicates, such as sodium silicates and potassium silicates, and mixtures thereof. Even more preferably, the water-soluble silicate is selected from sodium silicates. Even more preferably, the water-soluble silicate is sodium metasilicate.

[0046] The water-soluble silicate(s) may be included in the first composition of the present invention in an amount of 0.05 wt% or more, preferably 0.1 wt% or more, more preferably 0.2 wt% or more, even more preferably 0.5 wt% or more, and in par in particular 0.8% by weight or more; and / or 10% by weight or less, preferably 5% by weight or less, and more preferably 3% by weight or less, and even more preferably 2% by weight or less, relative to the total weight of the composition.

[0047] The water-soluble silicate(s) may be included in the first composition of the present invention in an amount of 0.05% to 10% by weight, preferably 0.1% to 5% by weight, more preferably 0.2% to 3% by weight, even more preferably 0.5% to 2% by weight, and in particular 0.8% to 2% by weight, relative to the total weight of the composition.

[0048] The application of the first composition to the keratinous fibers can be carried out by any means conventional in the art, such as the use of hands, a spray, a brush and a comb.

[0049] {Step ii)}

[0050] Step ii) is a step of applying to the keratinous fibers, to which the first composition was applied in step i), a second composition comprising at least one acidic compound, in which the second composition has a pH value of 1 to 6.

[0051] Step ii) is carried out after step i). The method according to the present invention may comprise one or more additional steps between steps i) and ii), but, even in such an embodiment, step ii) is always carried out after step i). Step ii) may be carried out directly after step i).

[0052] The second composition may take various forms, such as a solution, gel, lotion, serum, suspension, dispersion, fluid, milk, paste, cream, emulsion (in O / W or W / O form), or the like. It is preferable that the second composition according to the present invention is an aqueous solution.

[0053] The second composition has a pH value ranging from 1 to 6. Preferably, the second composition has a pH range from 1 to 5, and preferably from 1 to 4. The pH value of the second composition can be adjusted to the desired value using alkaline agent(s) and / or acidic agent(s) commonly used in the field of cosmetics.

[0054] (Acid compound)

[0055] The term "acidic compound" herein refers to compounds that function as an acid. The term "acidic compound" cannot refer to amphoteric compounds that function as an acid and a base, such as amino acids and peptides.

[0056] The second composition comprises at least one acidic compound that dissolves in the second composition. Therefore, the acidic compound may be soluble in water. The term "water soluble" herein means a substance having solubility in water at ordinary room temperature (25°C) and atmospheric pressure (760 mmHg) greater than 0.5% by weight, preferably greater than 1% by weight.

[0057] The acidic compound used in the present invention is an organic acid or an inorganic acid. Preferably, the acidic compound of the present invention is selected from organic acids.

[0058] The inorganic acid may be selected, for example, from the group consisting of hydrogen chloride (HCl), sulfuric acid (H2SO4), nitric acid (HNO3), phosphoric acid (H3PO4), and combinations thereof. In one embodiment of the present invention, the acidic compound may be inorganic phosphoric acids, such as pyrophosphoric acid, trimetaphosphoric acid, and hexametaphosphoric acid, as well as combinations thereof.

[0059] The organic acid may be selected from, for example, those having one or more acid groups selected from the group consisting of a carboxylic acid group, a sulfuric group, a sulfonic group, a phosphonic group, a phosphoric group, a phenolic hydroxyl group, and a mixture thereof. Preferably, the organic acid is selected from those having one or more carboxylic acid groups and / or phosphoric groups.

[0060] In a preferred embodiment of the present invention, the organic acid is a carboxylic acid. Non-limiting examples of useful carboxylic acids may include oxalic acid, malonic acid, malic acid, glutaric acid, citraconic acid, citric acid, maleic acid, glycolic acid, succinic acid, adipic acid, tartaric acid, acetic acid, lactic acid, glyoxylic acid, glyoxylic acid monohydrate, gluconic acid, propionic acid, aconitic acid and EDTA, as well as combinations thereof.

[0061] In one embodiment of the present invention, the carboxylic acid may comprise from 2 to 10 carbon atoms, preferably from 2 to 8 carbon atoms, and more preferably from 2 to 7 carbon atoms.

[0062] In one embodiment of the present invention, the organic acid is selected from phosphoric acids. Non-limiting examples of useful phosphoric acids may include phytic acid, inositol triphosphate, inositol pentakisphosphate, adenosine tripolyphosphate and triphosphate, as well as combinations thereof.

[0063] In one embodiment of the present invention, the organic acid is selected from monocarboxylic acids. Examples of suitable monocarboxylic acids include, but are not limited to, aryl, (hetero)cyclic, alkyl and / or aliphatic monocarboxylic acids such as, for example, acetic acid, mono-, di- or trichloroacetic acid, glyoxylic acid, glycolic acid, acrylic acid, methacrylic acid, pyruvic acid, propionic acid, D-gluconic acid and D-galacturonic acid.

[0064] In one embodiment, the organic acid may have two or more acid groups. Such organic acids may be those having two acid groups, those having three acid groups, and those having four or more acid groups.

[0065] In one embodiment of the present invention, the organic acid having two or more acid groups may be a polycarboxylic acid.

[0066] As polycarboxylic acid having two carboxylic acid groups, mention may be made of dicarboxylic acids, such as oxalic acid, malonic acid, malic acid, glutaric acid, citraconic acid, maleic acid, tartaric acid, succinic acid, adipic acid and azelaic acid.

[0067] As the polycarboxylic acid having three carboxylic acid groups, tricarboxylic acids, such as citric acid and aconitic acid, may be mentioned.

[0068] In a preferred embodiment, the organic acid is a tricarboxylic acid, such as citric acid and aconitic acid.

[0069] As the polycarboxylic acid having four or more carboxylic acid groups, tetracarboxylic acids, such as EDTA, pentacarboxylic acids and hexacarboxylic acids may be mentioned.

[0070] In a preferred embodiment of the present invention, the acidic compound may be selected from hydroxy acids. Therefore, the composition according to the present invention may comprise at least one hydroxy acid as component (b).

[0071] The hydroxy acid may comprise at least one mono- or polycarboxylic acid comprising at least one hydroxyl functional group. The hydroxy acid (a) may be selected from α- and [3-hydroxy acids. For example, the hydroxy acid (a) may be an α-hydroxy acid. The α and [3 positions reflect the fact that at least one of the hydroxyl functions occupies an α or [3 position relative to at least one of the carboxyl functions of the acid, i.e. it is attached, respectively, either to the carbon carrying the hydroxyl function or to the carbon adjacent to that carrying the carboxyl function. The acid may be present in a form selected from free acids, associated salts thereof (such as salts with organic bases and alkali metals), for example depending on the final pH given to the composition, and optionally the corresponding lactides (i.e. the form obtained by self-esterification of the molecules).

[0072] The term "α-hydroxy acid" herein refers to an acid, such as carboxylic acid or phosphoric acid, which has at least one hydroxyl group on the adjacent (alpha) carbon atom.

[0073] The α-hydroxy acid can be represented by the following chemical formula:

[0074] (Ra)(Rb)C(OH)COOH

[0075] where

[0076] Ra and Rb are H, F, Cl, Br, I, an alkyl or aralkyl group in saturated form or unsaturated, isomeric or non-isomeric, straight or branched chain or cyclic, having 1 to 7 carbon atoms, and in addition Ra and Rb may carry OH, CHO, COOH and an alkoxyl group having 1 to 6 carbon atoms.

[0077] Typical alkyl, aralkyl and alkoxyl groups for Ra and Rb include methyl, ethyl, propyl, isopropyl, butyl and pentyl.

[0078] The α-hydroxy acid may be selected, for example, from the group consisting of glycolic acid, lactic acid, malic acid, citric acid, tartaric acid, mandelic acid, gluconic acid, phytic acid and a mixture thereof.

[0079] It is preferable that the hydroxy acid has two or more carboxylic groups, and more preferably two or three carboxylic groups.

[0080] It is also preferred that the hydroxy acid has one or more hydroxyl groups, and more preferably one or two hydroxyl groups.

[0081] It is more preferred that the hydroxy acid is selected from the group consisting of glycolic acid, lactic acid, malic acid, citric acid, tartaric acid, mandelic acid, gluconic acid, mucic acid, phytic acid and a mixture thereof.

[0082] In a further preferred embodiment, the acidic compound is selected from aliphatic monocarboxylic acids, such as glyoxylic acid, and hydroxy acids, particularly α-hydroxy acids, such as glycolic acid, lactic acid, malic acid, citric acid, tartaric acid, mandelic acid, gluconic acid, mucic acid, phytic acid, and mixtures thereof.

[0083] In a non-limiting embodiment, the organic acid compounds have a pKa of about 6 or less, preferably 5 or less, and more preferably 4.5 or less. The pKa of the organic acid is generally 0.5 or greater, more preferably 1 or greater.

[0084] In one embodiment of the present invention, the organic acid compounds may have a number average molecular weight of less than 1000 g per mole (g / mol), and preferably less than 750 g per mole (g / mol).

[0085] The acidic compound of the present invention may be in the form of a salt. The term "salt" herein refers to a salt formed by adding a suitable base(s) to the acidic compounds. Examples of salts include metal salts, for example salts with an alkali metal such as Na and K, and salts with an alkaline earth metal such as Mg and Ca, and ammonium salts.

[0086] In a preferred embodiment, the acidic compound is not in the form of a salt.

[0087] The acidic compound(s) may be included in the second composition of the present invention in an amount of 0.05% by weight or more, preferably 0.1% by weight or more, more preferably 0.2% by weight or more, so as to even more preferably 0.5% by weight or more, and in particular 0.8% by weight or more; and / or 10% by weight or less, preferably 5% by weight or less, and more preferably 3% by weight or less, and even more preferably 2% by weight or less, relative to the total weight of the composition.

[0088] The acidic compound(s) may be included in the second composition of the present invention in an amount of 0.05% to 10% by weight, preferably 0.1% to 5% by weight, more preferably 0.2% to 3% by weight, even more preferably 0.5% to 2% by weight, and in particular 0.8% to 2% by weight, relative to the total weight of the composition.

[0089] In a preferred embodiment of the present invention, the second composition comprises amino acids and / or oligopeptides in an amount of less than 1% by weight, preferably less than 0.5% by weight, and more preferably less than 0.1% by weight, relative to the total amount of the second composition. In another embodiment of the present invention, the second composition is free of amino acids and / or oligopeptides.

[0090] The application of the first composition to the keratinous fibers can be carried out by any means conventional in the art, such as the use of hands, a spray, a brush and a comb.

[0091] {Optional step(s)}

[0092] The method according to the present invention may include one or more optional steps in addition to steps i) and ii) explained above.

[0093] The method according to the present invention may also comprise a pretreatment step before step i), of washing and / or rinsing the keratinous fibers. The washing may be carried out using a shampoo. A neutralizing shampoo may in particular be used. The rinsing of the keratinous fibers may be carried out by any means, for example by washing the keratinous fiber under running water.

[0094] The pretreatment step may then comprise a step of drying the keratinous fibers. The drying of the keratinous fibers may be carried out with a conventional drying means such as a hair dryer.

[0095] The method according to the present invention may also comprise a step i') between steps i) and ii), consisting of leaving the first composition to rest on the keratinous fibers for a period ranging from 10 seconds to 2 hours, preferably from 1 minute to 1 hour, more preferably from 5 minutes to 50 minutes, and in particular from 10 minutes to 40 minutes.

[0096] The method according to the present invention may also comprise a step of rinsing and / or washing the keratinous fibers after step i) or after step i'), or between steps i) and ii). The washing may be carried out using a shampoo. A neutralizing shampoo can be used in particular. Rinsing the keratinous fibers can be done by any means, for example by washing the keratinous fiber under running water. This step can then further include a step of drying the keratinous fibers. Drying the keratinous fibers can be done using a conventional drying method such as a hair dryer.

[0097] In one embodiment of the present invention, step i) and step ii) are carried out successively and / or in stages. In another embodiment of the present invention, step ii) is carried out directly after step i), without any optional steps between step i) and step ii).

[0098] The method according to the present invention may also comprise a post-step after step ii), consisting of leaving the second composition to rest on the keratinous fibers for a period ranging from 1 second to 15 minutes, preferably from 5 seconds to 10 minutes, and more preferably from 10 seconds to 5 minutes.

[0099] The optional exposure time of step i') and the post-step may take place under an occlusive system. A non-limiting example of an occlusive system that may be mentioned is an occlusive system of the aluminum envelope type or covered with a plastic film. For example, the keratinous fibers may be wrapped in an aluminum or plastic film.

[0100] The water temperature for washing and / or rinsing in these optional steps is not particularly limited, for example, the water temperature is between 10°C and 50°C.

[0101] (Other ingredients)

[0102] The first and second compositions as explained above may include optional additional ingredients as explained below.

[0103] - Water

[0104] The first and second compositions of the present invention may also comprise water.

[0105] The amount of water in the second composition may be 50% by weight or more, preferably 65% ​​by weight or more, more preferably 80% by weight or more, and even more preferably 90% by weight or more, and may be 99.5% by weight or less, preferably 99% by weight or less, relative to the total weight of the composition.

[0106] - pH adjuster

[0107] The first and second compositions of the present invention may also comprise a pH adjuster, such as an alkaline agent and an acidic agent.

[0108] The pH of the first and second compositions may be adjusted to the desired value by adding at least one pH adjuster, such as an organic or inorganic base or an organic or inorganic acid or salts thereof to the composition. The base includes, for example, ammonium hydroxide, sodium hydroxide, sodium carbonate or a primary, secondary or tertiary (poly)amine, such as monoethanolamine, diethanolamine, triethanolamine, isopropanolamine or 1,3-propanediamine, as well as alkali or alkaline earth metal silicates, such as sodium metasilicate. Organic acid includes, for example, a carboxylic acid, a citric acid and a lactic acid. Inorganic acid includes, for example, a hydrochloric acid, a nitric acid, an orthophosphoric acid and a sulfonic acid. Salt includes, for example, sodium phosphate and trisodium phosphate.

[0109] The pH adjuster(s) may be present in an amount sufficient to adjust the pH of the composition to the desired value.

[0110] -Adjuvants

[0111] The first and second compositions of the present invention may also contain one or more adjuvants which may be conventionally used in compositions for treating and / or caring for keratinous fibers.The adjuvants may be selected from a physiologically acceptable medium, in particular water-soluble organic solvents; cationic, anionic, non-ionic or amphoteric surfactants; cationic, anionic, non-ionic, amphoteric or zwitterionic polymers or mixtures thereof; thickeners; penetrating agents; hair loss control agents; anti-dandruff agents; antioxidants; suspending agents; sequestering agents; buffers; perfumes; emollients; dispersing agents; dyes and / or pigments; film-forming agents; stabilizers; preservatives, such as phenoxyethanol; co-preservatives; opacifying agents; and mixtures thereof.

[0112] The adjuvants may be present in the second composition of the present invention in an amount preferably ranging from 0.01% to 20% by weight, preferably from 0.1% to 10% by weight, more preferably from 0.5% to 5% by weight, and even more preferably from 0.5% to 2% by weight, relative to the total weight of the composition.

[0113] In a specific embodiment of the present invention, the total amount of water-soluble silicate and water present in the first composition is 70 wt% or more, preferably 75 wt% or more, more preferably 80 wt% or more, even more preferably 85 wt% or more, preferably 90 wt% or more, more preferably 95 wt% or more, even more preferably 97 wt% or more, and especially 98 wt% or more, relative to the total weight of the first composition.

[0114] In a specific embodiment of the present invention, the total amount of the acid compound and water present in the second composition is 70% by weight or more, preferably 75% by weight or more, more preferably 80% by weight or more, even more preferably 85% by weight or more, preferably 90% by weight or more, more preferably 95% by weight or more, even more preferably 97% by weight or more, and in particular 98% by weight or more, relative to the total weight of the second composition.

[0115] [Necessary]

[0116] The present invention also relates to a kit which is intended to be used to implement the method according to the present invention.

[0117] Thus, the kit according to the present invention relates to a kit for treating and / or caring for keratinous fibers, preferably hair, comprising:

[0118] a first compartment including the first composition comprising at least one water-soluble silicate, and

[0119] a second compartment including the second composition comprising at least one acidic compound, wherein the second composition has a pH value of 1 to 6.

[0120] The first composition and the second composition used in the kit are the same as those explained in the process descriptions above.

[0121] In the kit according to the present invention, the first compartment and the second compartment may be provided such that the first composition is in the first compartment and the second composition is in the second compartment.

[0122] The first compartment and the second compartment are provided separately in the kit. Step i) and step ii) of the method according to the present invention may be carried out, for example, by dispensing or discharging the first composition from the first compartment, then dispensing or discharging the second composition from the second compartment, in a progressive manner.

[0123] [Use]

[0124] The present invention also relates to a use of the second composition comprising at least one acidic compound, wherein the second composition has a pH value of 1 to 6, for mitigating, reducing or repairing damage caused by the water-soluble silicate included in the first composition on keratinous fibers, preferably hair.

[0125] The first composition and the second composition used in the kit are the same as those explained in the process descriptions above.

[0126] The use of the present invention may include applying the second composition to keratinous fibers, such as hair, which become damaged due to water-soluble silicate. The application of the second composition may be carried out within one hour, preferably within 30 minutes, more preferably within 15 minutes, even more preferably within 10 minutes thereafter. the application of the first composition on the keratinous fibers.

[0127] EXAMPLES

[0128] The present invention will be described in more detail with the aid of examples. However, these examples should not be construed as limiting the scope of the present invention.

[0129] [Preparation]

[0130] (First composition)

[0131] The first compositions 1 and 2 were prepared by mixing sodium metasilicate, phenoxyethanol, and citric acid as a pH adjuster, if present, and water at ambient condition. The formulations of the first compositions and their pH values ​​are summarized in Table 1 below. The numerical values ​​of the ingredient amounts shown in Table 1 are all based on "% by weight" of active raw materials.

[0132] [Tables 1] Ingredients First composition 1 2 Sodium metasilicate 1 1 Phenoxyethanol 0.5 0.5 Citric acid - qs pH 9 Deionized water qs 100 qs 100 PH 12 9

[0133] (Second composition)

[0134] The second compositions 1 and 2 were prepared by mixing citric acid, phenoxyethanol, sodium metasilicate as pH adjuster, if present, and water at room temperature. The formulations of the second compositions 1 and 2 have been summarized in Table 2 below. The numerical values ​​of the ingredient amounts shown in Table 2 are all based on "% by weight" as active raw materials.

[0135] [Tables2] Ingredients Second Composition 1 2 Citric acid 1 1 Phenoxyethanol 0.5 0.5 Sodium metasilicate - qs pH 3 Deionized water qs 100 qs 100 PH 1 3

[0136] [Example 1 and comparative example 1]

[0137] (Measurement of denaturation temperature)

[0138] Three strands of hair (1 g, 27 cm) were used for each experiment. The strand of hair was washed with a cleansing shampoo composition, rinsed with deionized water at room temperature, and then towel dried. The formulation of the cleansing shampoo composition is shown in Table 3 below. The numerical values ​​of the ingredient amounts shown in Table 4 are all based on “% by weight” of active raw materials. In Example 1, 1 g of the first composition 1 was applied to the strand of hair using a brush, and then 1 g of the second composition 1 was applied gradually. In Comparative Example 1, the first composition 1 was applied in the same manner as in Example 1, but the second composition 1 was not applied.The obtained treated hair strands were subjected to denaturation temperature measurement analysis as explained below. In addition, the obtained treated hair strands were washed three times with an ordinary shampoo composition and the washed hair strands were also subjected to the analysis explained below. The formulation of the ordinary shampoo composition is shown in Table 3 below.

[0139] [Tables3] Ingredients Cleansing Shampoo Composition Regular Shampoo Composition Sodium Laureth Sulfate 12 15 Coco-Betaine 10 9 Cocamide MEA 0.5 - Sodium Chloride 0.5 - Glycerin 2 - Sodium Benzoate 0.5 0.5 Salicylic Acid 0.2 0.2 Laureth-12 0.25 - Polyquaternium-10 - 0.3 Citric Acid qs pH 5.3 qs pH 5.3 Sodium Hydroxide qs pH 5.3 qs pH 5.3 Deionized Water qs 100 qs 100

[0140] The treated hair strands were then stored at 24°C and 40% relative humidity for one hour. 7-10 mg of hair strand sample was prepared by cutting the strand and the sample was placed in a stainless steel container. After adding 50 μl of deionized water into the stainless steel container, the container was sealed and stored overnight.

[0141] The denaturation temperature of the treated hair strand sample was measured using a high pressure differential scanning calorimeter (HP-DSC, Perkin Elmer DSC8000). Heating was carried out from 25 °C to 190 °C at a heating rate of 10 °C / min. The calculated denaturation temperatures are summarized in Table 4. The reference in Table 4 indicates the result of the untreated hair strand.

[0142] The denaturation temperature of keratinous fibers corresponds to the temperature of change from structure a to structure [3 of the keratin protein. Therefore, keratinous fibers having a higher denaturation temperature have higher integrity because the higher denaturation temperature indicates that the keratin protein can maintain its structure at a higher temperature.

[0143] [Tables4] Step i) Step ii) Denaturation temperature (°C) Denaturation temperature (°C) after three shampoos Ex. 1 First composition 1 Second composition 1 157.8 158.2 Ex. comp. 1 First composition 1 - 146.7 147.8 Reference - - 151.9 152.0

[0144] As can be seen from the results in Table 1, the keratinous fiber treated with the method according to Comparative Example 1 showed a lower denaturation temperature than the reference sample. This indicates that the keratinous fiber was damaged by the application of the first composition comprising a water-soluble silicate. On the other hand, the keratinous fiber treated according to the method of Example 1 showed a higher denaturation temperature than that of Comparative Example 2, and even higher than that of the reference sample. These results indicate that the application of the second composition can mitigate the damage caused by the application of the first composition to the hair, and that the application of the second composition can even improve the integrity of the keratinous fibers. Furthermore, this effect can last up to at least three shampoos.Therefore, it can be said that the effect of providing high integrity with keratinous fibers could last for a long time. These effects seem to be achieved because the internal repair of keratinous fibers can be enhanced by the method according to the present invention.

[0145] [Example 2 and comparative example 2]

[0146] (Observation by fluorescence microscopy)

[0147] Two strands of hair (1 g, 27 cm) were used for each experiment. The strand of hair was washed with a cleansing shampoo composition, rinsed with deionized water at room temperature, and then towel dried. The formulation of the cleansing shampoo composition was the same as that used in Example 1 above. In Example 2, 1 g of the first composition 2 was applied to the strand of hair using a brush, and then 1 g of the second composition 2 was applied gradually. In Comparative Example 2, the first composition 2 was applied in the same manner as in Example 2, but no second composition was applied. Then, the strands of hair obtained according to Example 2 and Comparative Example 2 were dried naturally under ambient condition.

[0148] For a fluorescent dye solution, a 0.05% w / v Rhodamine B solution was prepared with 10 v / v% ethanol and 90 v / v% pH 9 buffer solution. Rhodamine B was obtained from Sigma-Aldrich and the buffer solution was obtained from DKK-TOA corporation. 2 g of the prepared fluorescent dye solution was applied to each of the treated hair strands, and the hair strands were then kept at 30°C and 40% relative humidity for 30 minutes. The dyed hair strands were then rinsed with deionized water and dried naturally in a dark room. The hair strands were then sliced ​​using a slicer (JASCO Slice Mater HS-1) to obtain keratin fiber samples with a thickness of 30-50 μm. The cross-section of the samples was observed by a fluorescence microscope (KEYENCE BZ-X700). The observed images are shown in [Fig. 1].

[0149] The more damaged the hair fiber is, the more penetration of hydrophilic fluorescent dyes can be observed. Therefore, lower fluorescence intensity of hair fiber cross-sections indicates less absorption of fluorescent dyes, and therefore less damage to the hair fiber.

[0150] As can be seen in [Fig. 1], the hair sample according to Example 2 showed a fluorescence intensity similar to that of the reference which comes from the untreated hair strand. On the other hand, the hair sample according to Comparative Example 2 showed a higher fluorescence intensity indicating that the keratinous fiber was damaged by the application of the first composition 2 including a water-soluble silicate. These results indicate that the damage caused by the water-soluble silicate can be mitigated and the integrity of the fiber can be maintained by the application of the second composition.

[0151] Therefore, it can be concluded that the method according to the present invention can mitigate, reduce or repair the damage caused to hair by water-soluble silicates, and moreover, the method is capable of improving the integrity of keratinous fibers. Therefore, the method according to the present invention is very useful for cosmetic purposes and can satisfy a large demand of consumers.

Claims

Claims

1. A method for treating and / or caring for keratinous fibers, preferably hair, comprising the steps of: i) applying to the keratinous fibers a first composition comprising at least one water-soluble silicate; and ii) applying to the keratinous fibers a second composition comprising at least one acidic compound, wherein the second composition has a pH value of 1 to 4, wherein step ii) is carried out directly after step i).

2. A method according to claim 1, wherein the water-soluble silicate is selected from alkali or alkaline earth metal silicates and mixtures thereof, preferably from alkali metal silicates, such as sodium silicates, potassium silicates and mixtures thereof, and more preferably from sodium silicates.

3. A method according to any one of the preceding claims, wherein the acidic compound is selected from organic acids, preferably selected from organic acids having one or more carboxylic acid groups and / or phosphonic groups.

4. A method according to any one of the preceding claims, wherein the acidic compound is selected from hydroxy acids, preferably from α-hydroxy acids, and aliphatic monocarboxylic acids.

5. A method according to any preceding claim, wherein the acidic compound is selected from glyoxylic acid, lactic acid, malic acid, citric acid, tartaric acid, mandelic acid, gluconic acid, phytic acid and a mixture thereof.

6. A method according to any preceding claim, wherein the pH value of the first composition is from 8 to 13, preferably from 8 to 12.5, and more preferably from 8.5 to 12.5.

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