Hair Treatment Method

Abstract

The present invention provides a hair treatment method comprising step 1 and step 2, step 2 being carried out subsequent to step 1.　(Step 1) A step for applying, to the skin of a scalp, a cosmetic composition that contains a pH buffering agent, an antioxidant, and a pH responsive thickener and that has a viscosity of 1-30,000mPa∙s when the pH is 4.1. (Step 2) A step for applying, to hair, at least one hair treatment agent composition selected from among hair color compositions, hair bleach compositions, perm compositions, and relaxer compositions.　This hair treatment method enables enhancement of scalp protection ability and maintaining of a hair treatment effect that is desired to be achieved. In addition, since the cosmetic composition in use has a favorable balance between coating properties and dripping properties, said composition is capable of improving convenience of use for a user.

Description

[Technical field]

[0001] The present invention relates to a hair treatment method, and more particularly to a hair treatment method for protecting the scalp from damage caused by a hair color composition, a hair bleach composition, a perm composition or a relaxer composition. [Background technology]

[0002] Although hair treatments such as hair coloring, hair bleaching, perming, or relaxers (e.g., hair straightening) can change a person's appearance and give them confidence, hair treatments such as hair coloring agents, hair bleaching agents, perming agents, and relaxers can cause problems such as damage to the hair and irritation to the scalp. For this reason, hair treatment methods have been developed in this technical field to protect the scalp from damage caused by hair coloring compositions, hair bleaching compositions, perming compositions, or relaxer compositions. For example, Patent Document 1 discloses a scalp isolating composition used before hair coloring / perming, which contains a nonionic surfactant, a water-soluble polymer, an antioxidant, and a pH buffer, and a method for using the same.

[0003] (Patent Document 1) China Patent Application Publication No. 107837212 Summary of the Invention

[0004] The present invention provides a hair treatment method comprising the following steps 1 and 2, in which step 2 is carried out after step 1. (Step 1) A step of applying to the scalp a cosmetic composition containing the following components (A) to (C) and having a viscosity of 1 to 30,000 mPa s at pH 4.1 (unless otherwise specified in the present specification, pH refers to "pH at 25°C"). (A) pH buffer (B) an antioxidant, and (C) pH-responsive thickener (Step 2) A step of applying to the hair at least one hair treatment composition selected from a hair color composition, a hair bleach composition, a perm composition, and a relaxer composition.

[0005] The present invention also provides a cosmetic composition for protecting the scalp, which comprises the following components (A) to (C) and has a viscosity of 1 to 30,000 mPa·s at pH 4.1: (A) pH buffer (B) an antioxidant, and (C) pH-responsive thickener

[0006] Furthermore, the present invention provides a kit comprising at least one hair treatment composition selected from the group consisting of a hair color composition, a hair bleach composition, a perm composition and a relaxer composition, and the cosmetic composition of the present invention.

[0007] The composition and method of use disclosed in Patent Document 1 reduce or mitigate damage caused by hair treatments such as hair colorants, but there is room for improvement in terms of scalp protection. Furthermore, research has revealed that the composition has a problem of reducing the dyeing power of hair colorants.

[0008] As a result of intensive research, the present inventors have found that by first applying a cosmetic composition containing a pH buffer, an antioxidant, and a pH-responsive thickener, and having a viscosity at pH 4.1 of 1 to 30,000 mPa s, prior to applying a hair treatment composition, it is possible to significantly improve scalp protection ability while also maintaining the intended hair treatment effects, such as hair coloring, hair bleaching, perms or relaxers, thereby solving the above-mentioned problems.

[0009] As can be seen from an embodiment of the present invention, the hair treatment method of the present invention applies a cosmetic composition to the scalp before hair treatment, so that the scalp protection ability can be significantly improved and damage to the scalp caused by the hair treatment composition can be reduced or alleviated. In addition, the cosmetic composition used can be well maintained without reducing the intended hair treatment effect even after application to the scalp. For example, when a hair color composition is applied, an excellent dyeing effect can be maintained. In addition, the present invention can maintain a good balance between the applicability and dripping property of the cosmetic composition, improving the convenience of use for users.

[0010] Hereinafter, an embodiment of the present invention will be described in detail.

[0011] The present invention provides a hair treatment method (e.g., hair coloring, hair bleaching, perming, relaxer, etc.) comprising uniformly applying the cosmetic composition of the present invention to the scalp, applying a hair treatment composition (e.g., a composition such as a hair coloring agent, hair bleaching agent, perm agent, relaxer agent, etc.) to the hair, and then optionally rinsing and drying as necessary.

[0012] Specifically, the hair treatment method of the present invention includes the following steps 1 and 2, with step 2 being carried out after step 1. (Step 1) A step of applying to the scalp a cosmetic composition containing the following components (A), (B), and (C) and having a viscosity of 1 to 30,000 mPa s at pH 4.1: (A) a pH buffer; (B) an antioxidant; and (C) pH-responsive thickener (Step 2) applying at least one hair treatment composition selected from a hair color composition, a hair bleach composition, a perm composition, and a relaxer composition to the hair.

[0013] From the viewpoint of obtaining the effect of excellent scalp protection ability, in the present invention, the cosmetic composition used in step 1 is applied before the application of the hair treatment composition, thereby making it possible to protect the scalp from damage caused by hair treatment. Moreover, since the cosmetic composition does not affect the hair treatment, excellent hair treatment effects can be maintained.

[0014] The hair treatment includes a chemical treatment using an alkaline treatment agent, specifically, hair coloring, hair bleaching, perms, relaxers, and the like.

[0015] Here, a relaxer is a hair treatment for curly hair that relaxes and straightens the hair by treating the hair under strong alkaline conditions with a hair treatment agent containing an alkaline agent such as sodium hydroxide or guanidine hydroxide. Perms are hair treatments in which the cystine bonds in hair are cleaved with a first solution containing a reducing substance such as thioglycolate or cysteine ​​or an alkaline agent, the hair is swelled and softened, and the hair is set into a desired shape by either wrapping it around a rod or the like (wave perm) or stretching it linearly with a comb, iron, or the like (straight perm), and then the cystine bonds are reformed with a second solution containing an oxidizing agent such as bromate or hydrogen peroxide, thereby fixing the desired shape. In addition to alkaline perms that use the above-mentioned alkaline first perm solution, there are also acidic or neutral perms that use glyceryl thioglycolate, butyrolactone thiol, or the like as reducing substances. Hair coloring is a hair treatment in which a first agent containing an alkaline agent and an oxidative dye intermediate is mixed with a second agent containing an oxidizing agent such as hydrogen peroxide, and the resulting mixture is applied to the hair to dye the hair. Hair bleaching is a hair treatment in which a first agent containing an alkaline agent is mixed with a second agent containing an oxidizing agent such as hydrogen peroxide, and the resulting mixture is applied to the hair to decolorize it. In some cases, hair colorants and hair bleaches are used in combination with granulated substances such as persulfates to improve the bleaching power.

[0016] In step 1, the cosmetic composition is applied to the scalp, and may be applied to either dry or wet scalp. The cosmetic composition of the present invention does not significantly affect the hair treatment in step 2 and does not irritate the scalp, so a portion of the composition may be applied near the root of the hair. The area to which the cosmetic composition is applied may be an area where the hair treatment composition can come into contact with the scalp in step 2, and may be the entire scalp or a portion of the scalp. The amount of the cosmetic composition applied to the scalp is 8 to 40 μl / cm from the viewpoint of obtaining a sufficient scalp protection effect. 2 The range is preferably 13 to 27 μl / cm 2 Range: 20-27μl / cm 2 It is more preferable that the range is .

[0017] The hair treatment may be performed between step 1 and step 2 by applying a pretreatment such as a hair cosmetic composition described in JP 2019-123710 A, as appropriate, but does not include a step of washing off the cosmetic composition used in step 1. The timing of performing the hair treatment in step 2 is not particularly limited, and the hair treatment may be performed immediately after applying the cosmetic composition used in step 1 to the scalp, or may be performed after several minutes to several hours have passed. From the viewpoint of maintaining the hair treatment effect to be achieved and obtaining a sufficient scalp protection effect, it is preferable to perform step 2 immediately after applying the cosmetic composition used in step 1 to the scalp.

[0018] The mass of the hair treatment composition applied to the hair in step 2 is expressed as a bath ratio to the mass of hair (mass of hair treatment composition / mass of hair) of preferably 0.05 or more, more preferably 0.10 or more, even more preferably 0.25 or more, even more preferably 0.5 or more, and is preferably 100 or less, more preferably 90 or less, even more preferably 40 or less, even more preferably 5 or less, even more preferably 3 or less, and even more preferably 2 or less.

[0019] In step 2, from the viewpoint of promoting the penetration of the hair treatment composition and enhancing the treatment effect, the treatment time is preferably 1 minute or more, more preferably 3 minutes or more, and even more preferably 5 minutes or more, and is preferably 1 hour or less, more preferably 30 minutes or less, and even more preferably 20 minutes or less. At this time, the hair may be heated from the viewpoint of promoting the penetration of the first agent. When heating, it is preferably heated at 40 to 90°C.

[0020] After step 2, if necessary, the hair may be rinsed with water, washed and rinsed with shampoo as appropriate. The hair may further be treated with a rinse, conditioner, etc., and rinsed. After that, the hair is preferably towel-dried to remove excess water and then dried.

[0021] The cosmetic composition used in step 1 will be described below.

[0022] (Component (A)) Component (A) is a pH buffer, and is not particularly limited, but preferably includes a buffer solution of a conjugate acid-base pair. Specific examples include monocarboxylic acids such as acetic acid and propionic acid and their salts; dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, and phthalic acid and their salts; polycarboxylic acids such as polyglutamic acid and their salts; hydroxycarboxylic acids such as glycolic acid, lactic acid, hydroxyacrylic acid, glyceric acid, malic acid, tartaric acid, and citric acid and their salts; acidic amino acids such as glutamic acid and aspartic acid and their salts; inorganic acids such as hydrochloric acid, phosphoric acid, and sulfuric acid and their salts; and barbituric acid and its salts. The salts of the above acids are not particularly limited, but examples thereof include alkali metal salts such as sodium salts and potassium salts. These pH buffers may be used alone or in combination of two or more.

[0023] In hair treatment such as hair coloring, an alkaline hair treatment agent is generally used, and the pH of the scalp is likely to increase during the hair treatment, causing irritation. Therefore, from the viewpoint of suppressing the increase in the pH of the scalp, it is preferable to use a pH buffer agent having a buffering capacity at least between pH 4.5 and 5.5.

[0024] As a pH buffer having a buffering capacity at least between pH 4.5 and 5.5, it is preferable to adjust the pH using an acid or its salt having a pKa (25°C) of 4.0 to 6.5. Specific examples of the acid include barbituric acid (pKa1=4.04), succinic acid (pKa1=4.21, pKa2=5.64), citric acid (pKa2=4.76, pKa3=6.40), acetic acid (pKa2=4.76), malic acid (pKa2=5.13), phthalic acid (pKa2=5.41), and carbonic acid (pKa2=6.35).

[0025] In particular, from the viewpoint of improving scalp protection ability, maintaining a good balance between application ease and dripping resistance, and maintaining the intended hair treatment effect, component (A) is preferably succinic acid and its salts, malic acid and its salts, citric acid and its salts, or any combination of the above acids and their salts, more preferably citric acid and its salts, and even more preferably citric acid and sodium citrate.

[0026] The content of component (A) (in the case of a conjugate acid-base pair, the total content) is, for example, more than 0.15% by mass, preferably 0.2% by mass or more, more preferably 0.5% by mass or more, even more preferably 1.0% by mass or more, and even more preferably 1.5% by mass or more, based on the entire cosmetic composition, from the viewpoint of improving the scalp protection ability and maintaining the hair treatment effect to be achieved. Also, from the same viewpoint, it is, for example, 10.0% by mass or less, preferably 9.0% by mass or less, more preferably 8.0% by mass or less, even more preferably 6.0% by mass or less, and even more preferably 4.0% by mass or less. More specifically, from the above viewpoints, it is, for example, more than 0.15 mass% and 10.0 mass% or less, preferably 0.2 mass% or more and 9.0 mass% or less, more preferably 0.5 mass% or more and 8.0 mass% or less, even more preferably 1.0 mass% or more and 6.0 mass% or less, still more preferably 1.0 mass% or more and 4.0 mass% or less, and even more preferably 1.5 mass% or more and 4.0 mass% or less.

[0027] (Component (B)) Component (B) is an antioxidant, and is not particularly limited, but examples thereof include dibutylhydroxytoluene, butylhydroxyanisole, δ Examples of the antioxidants include phenolic antioxidants such as vitamin E such as tocopherol or derivatives thereof (specific examples include tocopherol acetate, etc.), thiotaurine, thioglycolic acid, propanoic acid, tert-butylhydroquinone, nicotinic acid or derivatives thereof, catechin, evening primrose extract, β-carotene, flavonoid compounds, sulfurous acid or salts thereof, ascorbic acid or salts or derivatives thereof (specific examples include ascorbic acid glucoside, magnesium ascorbyl phosphate, erythorbic acid, sodium erythorbate, etc.), L-cysteine ​​or salts or derivatives thereof, N-acetyl-L-cysteine ​​or salts or derivatives thereof, and polyphenol compounds. These antioxidants may be used alone or in combination of two or more. The salts of the above acids are not particularly limited, but examples thereof include alkali metal salts such as sodium salts and potassium salts.

[0028] In particular, from the viewpoint of improving scalp protection ability, maintaining a good balance between application ease and dripping resistance, and maintaining the intended hair treatment effect, component (B) is preferably ascorbic acid or a salt or derivative thereof, dibutylhydroxytoluene, or catechin, more preferably ascorbic acid or a salt or derivative thereof (e.g., ascorbic acid glucoside, magnesium ascorbyl phosphate, erythorbic acid, sodium erythorbate), and even more preferably ascorbic acid or ascorbic acid glucoside.

[0029] The total content of component (B) is, for example, 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 0.2% by mass or more, based on the entire cosmetic composition, from the viewpoint of improving scalp protection ability, maintaining a good balance between application property and dripping property, and maintaining the hair treatment effect to be achieved. Also, from the same viewpoint, it is, for example, 5.0% by mass or less, preferably 3.0% by mass or less, more preferably 1.5% by mass or less, even more preferably 1.0% by mass or less, and even more preferably 0.7% by mass or less. More specifically, from the above viewpoint, it is, for example, 0.01 mass% or more and 5.0 mass% or less, preferably 0.1 mass% or more and 3.0 mass% or less, more preferably 0.2 mass% or more and 1.5 mass% or less, even more preferably 0.2 mass% or more and 1.0 mass% or less, and even more preferably 0.2 mass% or more and 0.7 mass% or less.

[0030] The total content of component (A) and component (B) is, for example, preferably 0.2% by mass or more, more preferably 1.0% by mass or more, even more preferably 2.3% by mass or more, and even more preferably 2.5% by mass or more, based on the entire cosmetic composition, from the viewpoint of improving scalp protection ability and maintaining the hair treatment effect to be achieved. Also, from the same viewpoint, for example, it is 10.0% by mass or less, preferably 8.0% by mass or less, more preferably 6.0% by mass or less, even more preferably 5.5% by mass or less, even more preferably 5.0% by mass or less, even more preferably 4.5% by mass or less, and even more preferably 4.0% by mass or less. More specifically, from the above viewpoints, it is, for example, 0.2 mass% or more and 10.0 mass% or less, preferably 1.0 mass% or more and 8.0 mass% or less, more preferably 2.3 mass% or more and 6.0 mass% or less, even more preferably 2.3 mass% or more and 5.5 mass% or less, even more preferably 2.5 mass% or more and 5.0 mass% or less, even more preferably 2.5 mass% or more and 4.5 mass% or less, and even more preferably 2.5 mass% or more and 4.0 mass% or less.

[0031] From the viewpoint of improving the scalp protection ability and from the viewpoint of maintaining the hair treatment effect to be achieved, the mass ratio of component (A) to component (B) (component (A) / component (B)) is, for example, 1.0 or more, preferably 1.1 or more, more preferably 1.5 or more, even more preferably 2.0 or more, and even more preferably 3.0 or more. From the same viewpoint, it is, for example, 8.0 or less, preferably 7.5 or less, more preferably 6.5 or less, even more preferably 6.0 or less, and even more preferably 5.0 or less. More specifically, from the above viewpoints, it is, for example, 1.0 or more and 8.0 or less, preferably 1.1 or more and 7.5 or less, more preferably 1.5 or more and 6.5 or less, even more preferably 2.0 or more and 6.0 or less, and even more preferably 3.0 or more and 5.0 or less.

[0032] (Component (C)) Component (C) is a pH-responsive thickener, and can increase the viscosity of the cosmetic composition according to an increase in the pH of the cosmetic composition. Component (C) is not particularly limited, but is preferably an ionic water-soluble polymer, more preferably an alkali-thickening ionic water-soluble polymer, from the viewpoint of improving scalp protection ability. When the ionic water-soluble polymer is dispersed or dissolved in water, the viscosity does not increase much because the dissociation group contained therein is not dissociated or only a small amount is dissociated, but when a base such as sodium hydroxide, potassium hydroxide, or triethanolamine is added, the pH increases, the dissociation group dissociates and ionizes, and the repulsive force of the generated charge causes swelling and increases the viscosity. It is preferable that the pH-responsive thickener increases the viscosity according to an increase in pH at least in a part or all of the pH range of 3 to 7.

[0033] The pH-responsive thickener is more preferably an ionic water-soluble polymer having at least one selected from unneutralized carboxyl groups and unneutralized sulfonic acid groups, and even more preferably an ionic water-soluble polymer having at least an unneutralized carboxyl group. For example, linear or branched polymers such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, styrene sulfonic acid, vinyl benzoic acid, 2-acrylamido-2-methyl-1-propanesulfonic acid, dimethylolpropionic acid, or crosslinked polymers and copolymers thereof can be mentioned. Specifically, acrylic polymers or copolymers such as polyacrylic acid, carboxyvinyl polymer, sodium polyacrylate, and acrylic acid / alkyl methacrylate copolymers; methacrylic acid polymers or copolymers such as polymethacrylic acid and methacrylic acid / alkyl methacrylate copolymers can be mentioned. These pH-responsive thickeners may be used alone or in combination of two or more kinds.

[0034] In particular, from the viewpoint of improving scalp protection ability and maintaining a good balance between application property and dripping property, component (C) is preferably an acrylic acid / alkyl methacrylate copolymer, a methacrylic acid / alkyl methacrylate copolymer, or a carboxyvinyl polymer, and more preferably a carboxyvinyl polymer. Commercially available carboxyvinyl polymers include the Carbomer series, such as Carbopol 910, Carbopol 934, Carbopol 940, Carbopol 941, Carbopol 980, and Carbopol 981 (all manufactured by Lubrizol Advanced Materials, Inc.). Commercially available acrylic acid / alkyl methacrylate copolymers include Carbopol 1382, Carbopol ETD2020, PEMULEN TR-1, and PEMULEN TR-2 (all manufactured by Lubrizol Advanced Materials, Inc.).

[0035] The total content of component (C) is, for example, 0.1% by mass or more, preferably 0.2% by mass or more, based on the entire cosmetic composition, from the viewpoint of improving scalp protection ability and maintaining a good balance between application property and dripping property. From the same viewpoint, it is, for example, 3.0% by mass or less, preferably 2.5% by mass or less, more preferably 2.0% by mass or less, even more preferably 1.7% by mass or less, and even more preferably 1.5% by mass or less. More specifically, for example, it is 0.1 mass% or more and 3.0 mass% or less, preferably 0.1 mass% or more and 2.5 mass% or less, more preferably 0.1 mass% or more and 2.0 mass% or less, even more preferably 0.2 mass% or more and 1.7 mass% or less, and even more preferably 0.2 mass% or more and 1.5 mass% or less.

[0036] (Component (D)) From the viewpoint of maintaining a good balance between application property and dripping property, the cosmetic composition used in step 1 may further contain a thickener (D) different from component (C), and is preferably a thickener such as a nonionic water-soluble polymer or an ionic water-soluble polymer that does not show an extreme change in viscosity between pH 3 and 7. From the viewpoint of viscosity stability, the ionic water-soluble polymer is preferably a salt type. For example, natural polymers, semi-synthetic polymers, and synthetic polymers are included. Specific examples of natural polymers include anionic water-soluble polymers such as xanthan gum, carrageenan, and alginic acid, and non-ionic water-soluble polymers such as starch. Specific examples of semi-synthetic polysaccharide polymers include non-ionic water-soluble polymers such as hydroxycellulose, hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, and methylcellulose, anionic water-soluble polymers such as stearoxy PG hydroxyethylcellulose sulfonate Na, and sodium carboxymethylcellulose, and cationic water-soluble polymers such as cationized cellulose. Specific examples of synthetic polymers include non-ionic water-soluble polymers such as polyvinylpyrrolidone and polyvinyl alcohol, and cationic water-soluble polymers such as cationized polyvinylpyrrolidone. These thickeners may be used alone or in combination of two or more. Examples of commercially available hydroxypropyl cellulose products include HPC-M and HPC-H (both manufactured by Nippon Soda Co., Ltd.), examples of commercially available sodium carboxymethyl cellulose products include CMC Daicel (both manufactured by Daicel Chemical Industries, Ltd.), examples of commercially available sodium stearoxy PG hydroxyethyl cellulose sulfonate products include Poise 310 (manufactured by Kao Corporation), and examples of commercially available xanthan gum products include xanthan gum food grade, xanthan gum CS, etc. (manufactured by Jungbunzlauer).

[0037] In particular, from the viewpoint of maintaining a good balance between application property and dripping property, preferred examples of component (D) are xanthan gum, hydroxyethyl cellulose, hydroxypropyl cellulose, sodium carboxymethyl cellulose, stearoxy PG hydroxyethyl cellulose sulfonate sodium, polyvinylpyrrolidone, and polyvinyl alcohol, and more preferred are stearoxy PG hydroxyethyl cellulose sulfonate sodium, xanthan gum, and hydroxyethyl cellulose.

[0038] The total content of component (D) is, for example, 0.1% by mass or more, preferably 0.2% by mass or more, based on the entire cosmetic composition, from the viewpoint of maintaining a good balance between application property and dripping property, and from the same viewpoint, for example, 5.0% by mass or less, preferably 4.0% by mass or less, more preferably 3.0% by mass or less, and even more preferably 2.5% by mass or less. More specifically, from the above viewpoint, it is, for example, 0.1 mass % or more and 5.0 mass % or less, preferably 0.1 mass % or more and 4.0 mass % or less, more preferably 0.2 mass % or more and 3.0 mass % or less, and even more preferably 0.2 mass % or more and 2.5 mass % or less.

[0039] (aqueous medium) The cosmetic composition used in step 1 may contain an aqueous medium according to need in order to improve compatibility between the components. The aqueous medium is an organic solvent compatible with water, and examples thereof include lower alcohols such as ethanol and isopropyl alcohol; low molecular weight diols and triols having 6 or less carbon atoms, such as 1,3-butylene glycol, glycerin, ethylene glycol, and propylene glycol, and mixtures thereof. In order to reduce irritation to the scalp, the content of the aqueous medium in the cosmetic composition is, for example, 10.0% by mass or less, preferably 5.0% by mass or less, more preferably 4.0% by mass or less, even more preferably 3.0% by mass or less, even more preferably 2.0% by mass or less, and even more preferably 1.0% by mass or less, and most preferably substantially none.

[0040] (water) The cosmetic composition used in step 1 also contains water. Examples of water that can be used include tap water, deionized water, and distilled water. The content of water in the cosmetic composition can be adjusted appropriately depending on the content of other ingredients, and is preferably 50% by mass or more, and more preferably 60% by mass or more, based on the total cosmetic composition. Also, it is preferably 99.8% by mass or less, and more preferably 98% by mass or less. More specifically, it is preferably 50% by mass or more and 99.8% by mass or less, and more preferably 60% by mass or more and 98% by mass or less.

[0041] (Surfactant) Although the surfactant is not an essential component, it can be used as necessary to improve the compatibility between components. The surfactant is not particularly limited, but examples thereof include ordinary cationic surfactants, anionic surfactants, nonionic surfactants, amphoteric surfactants, etc. In addition, if the content of the surfactant is high, it may cause a decrease in scalp protection ability and a decrease in the hair treatment effect to be achieved, so the total content of the surfactant is, for example, less than 5.0 mass%, preferably less than 4.0 mass%, more preferably less than 3.0 mass%, even more preferably less than 2.0 mass%, and even more preferably less than 1.0 mass% with respect to the entire cosmetic composition, and it is most preferable that it is substantially not contained.

[0042] (Other ingredients) In addition to the above-mentioned components, the cosmetic composition used in step 1 may contain other components that are typically used in cosmetic compositions, depending on the desired effect. Examples of such optional components include vitamins other than component (B); bactericides; anti-inflammatory agents such as glycyrrhizic acid and its salts, such as dipotassium glycyrrhizinate, and glycyrrhetinic acid and its salts; preservatives such as benzoic acid and its salts; chelating agents other than component (A); moisturizing agents such as sorbitol and panthenol; stabilizers; eucalyptus extracts such as polar solvent extracts of eucalyptus, conchiolin or its hydrolysates, honey, royal jelly, proteins or its hydrolysates obtained from silk, protein-containing extracts obtained from the seeds of legumes, ginseng extract, rice germ extract, hibamata extract, aloe extract, lotus extract, pomegranate extract, wild rose extract, chamomile extract, licorice extract, shell ginger leaf extract, and chlorella extract; fragrances; ultraviolet absorbers; shea butter; rose water; sunflower oil; orange oil; and eucalyptus oil, but other components used in the present invention are not limited to these.

[0043] The viscosity of the cosmetic composition used in step 1 will be described below.

[0044] The cosmetic composition used in step 1 is preferably a liquid or gel composition. In general, in order to reduce the irritation to the scalp when applying the hair composition, it is preferable that the pH of the hair composition is close to the pH of the scalp (3.5 to 6.0). However, if the pH of a commonly used alkaline hair treatment agent (such as a hair coloring agent) is reduced, the hair treatment effect is also reduced and the desired effect cannot be obtained. In particular, hair color compositions and hair bleach compositions produce their hair treatment effect through an oxidation-reduction reaction caused by an oxidizing agent, and therefore, in a system in which an antioxidant is present, the hair treatment effect may be reduced. Therefore, it is a problem to be solved in this technical field to maintain the hair treatment effect while protecting the scalp and reducing irritation to the scalp.

[0045] As a result of research, the present inventors have found that if the viscosity of the cosmetic composition used in step 1 at pH 4.1 is within a specific range, excellent scalp protection properties can be obtained while maintaining the desired hair treatment effects.

[0046] The viscosity of the cosmetic composition used in step 1 varies depending on the content and ratio of the above-mentioned components, but from the viewpoint of improving scalp protection ability and maintaining a good balance between application and dripping, the viscosity of the cosmetic composition used in step 1 at pH 4.1 is preferably 1 mPa·s or more, more preferably 10 mPa·s or more, even more preferably 100 mPa·s or more, even more preferably 300 mPa·s or more, especially preferably 800 mPa·s or more, especially preferably 1500 mPa·s or more. From the same viewpoint, it is preferably 30000 mPa·s or less, more preferably 25000 mPa·s or less, even more preferably 20000 mPa·s or less, even more preferably 15000 mPa·s or less, especially preferably 10000 mPa·s or less, especially preferably 5000 mPa·s or less, especially preferably 2500 mPa·s or less. The viscosity can be measured by the method described in the Examples. More specifically, from the above viewpoints, it is 1 mPa·s or more and 30,000 mPa·s or less, preferably 10 mPa·s or more and 30,000 mPa·s or less, more preferably 100 mPa·s or more and 30,000 mPa·s or less, even more preferably 300 mPa·s or more and 25,000 mPa·s or less, even more preferably 800 mPa·s or more and 20,000 mPa·s or less, even more preferably 800 mPa·s or more and 10,000 mPa·s or less, even more preferably 1500 mPa·s or more and 5000 mPa·s or less, and even more preferably 1500 mPa·s or more and 2500 mPa·s or less.

[0047] When the cosmetic composition used in step 1 has a viscosity of 1.1 to 10 times that of the composition at pH 4.1, the composition has a low viscosity and is easy to spread on the scalp when applied, and is expected to have an effect of preventing dripping, remaining on the scalp, and preventing increased scalp irritation due to mixing with compositions such as hair coloring agents, hair bleaching agents, perm agents, and relaxers by increasing viscosity at the initial stage when the pH rises upon contact with the composition. In addition, from the viewpoint of further improving the scalp protection ability and maintaining a good balance between application property and dripping property, the viscosity of the cosmetic composition used in step 1 at pH 5.0 is preferably 1.1 times or more, preferably 9 times or less, more preferably 7 times or less, even more preferably 5 times or less, and even more preferably 3 times or less, relative to the viscosity of the composition at pH 4.1. More specifically, from the above viewpoints, the increase is preferably 1.1 to 9 times, more preferably 1.1 to 7 times, even more preferably 1.1 to 5 times, and even more preferably 1.1 to 3 times.

[0048] As the pH adjuster, the pH of the cosmetic composition used in step 1 can be adjusted to a desired range by using a normal acid or base. Examples of the pH adjuster include organic acids, inorganic acids, organic bases, and inorganic bases. In the present invention, from the viewpoint of maintaining the hair treatment effect to be achieved, a base can be preferably used, and specifically, inorganic alkaline agents such as sodium hydroxide and potassium hydroxide; organic alkaline agents such as monoethanolamine, diethanolamine, triethanolamine, and aminopropanol; ammonia; ammonium chloride; and basic amino acids such as arginine. Among these, from the viewpoint of maintaining the hair treatment effect to be achieved, sodium hydroxide, potassium hydroxide, triethanolamine, and arginine are preferably used.

[0049] From the viewpoint of improving scalp protection ability and reducing damage to the scalp, the pH of the cosmetic composition used in step 1 is, for example, 7.0 or less, preferably 6.5 or less, more preferably 6.0 or less, even more preferably 5.0 or less, and even more preferably 4.8 or less. From the same viewpoint, it is preferably 3.0 or more, more preferably 3.5 or more. More specifically, from the above viewpoint, it is preferably 3.0 or more and 7.0 or less, more preferably 3.0 or more and 6.5 or less, even more preferably 3.5 or more and 6.0 or less, even more preferably 3.5 or more and 5.0 or less, and even more preferably 3.5 or more and 4.8 or less. The pH can be measured by the method described in the Examples.

[0050] The cosmetic composition used in step 1 may be filled into a container specifically for the scalp protection agent and used, or the cosmetic composition used in step 1 may be provided in a refill package together with the container specifically for the scalp protection agent and used. The scalp protective agent container may be any container capable of being filled with the cosmetic composition used in step 1, and examples of such containers include PETG ampoule containers manufactured by Pin Mao Plastics Industry Co., Ltd.

[0051] (Cosmetic composition and its manufacturing method) The present invention also includes a cosmetic composition for protecting the scalp and a method for making the same. The cosmetic composition may have the following embodiments: <Embodiment 1> The cosmetic composition may be similar to that used in step 1 above, that is, a composition containing the following components (A) to (C) and having a viscosity of 1 to 30,000 mPa·s at pH 4.1. (A) pH buffer (B) an antioxidant, and (C) pH-responsive thickener <Embodiment 2> The cosmetic composition of embodiment 2 of the present invention comprises the following components (A) to (C), has a viscosity of 1 to 30,000 mPa s at pH 4.1, and contains less than 5.0 mass % of a surfactant. (A) pH buffer (B) an antioxidant, and (C) pH-responsive thickener <Embodiment 3> The cosmetic composition according to embodiment 3 of the present invention is a composition that contains the following components (A) to (D) and has a viscosity of 1 to 30,000 mPa·s at pH 4.1. (A) pH buffer (B) an antioxidant; (C) a pH responsive thickener, and (D) a thickener different from the component (C) <Embodiment 4> The cosmetic composition according to embodiment 4 of the present invention is a composition that contains the following components (A) to (D) and has a viscosity of 1 to 30,000 mPa·s at pH 4.1. (A) pH buffer (B) an antioxidant; (C) a pH responsive thickener, and (D) Sodium stearoxy PG hydroxyethyl cellulose sulfonate <Embodiment 5> The cosmetic composition according to embodiment 5 of the present invention is a composition that contains the following components (A) to (D) and has a viscosity of 1 to 30,000 mPa·s at pH 4.1. (A) pH buffer (B) an antioxidant; (C) a pH responsive thickener, and (D) one or more selected from the group consisting of nonionic water-soluble polymers and ionic water-soluble polymers that do not show a significant change in viscosity between pH 3 and 7 The cosmetic composition of the present invention is not limited to the above embodiments. The cosmetic composition of the present invention can remarkably improve scalp protection. The cosmetic composition of the present invention can maintain the intended hair treatment effect well without reducing it even after application to the scalp. For example, when a hair color composition is applied, an excellent dyeing effect can be maintained. In addition, the balance between application property and dripping property can be well maintained, improving the convenience of use for users. There are no particular limitations on the method for producing the cosmetic composition of the present invention. For example, it can be produced by mixing components (A) to (C) and other appropriate components in a predetermined order. Specifically, in the case of the above-mentioned embodiment 1, component (C) is added to deionized water and stirred to make uniform, and then components (A) and (B) and other components as appropriate are added while cooling, stirred to make uniform, and then cooled to room temperature to obtain a cosmetic composition.

[0052] (Kit containing cosmetic composition) The present invention also includes a kit comprising the cosmetic composition and at least one hair treatment composition selected from the group consisting of a hair color composition, a hair bleach composition, a perm composition, and a relaxer composition. Among these, the hair color composition, the hair bleach composition, the perm composition, and the relaxer composition are not particularly limited and may be ordinary commercially available products, such as the Liese Foam Color Series and the Blone Fragrance and Luster Color Cream Series from Kao Corporation.

[0053] The hair treatment method of the present invention involves carrying out step 2 (applying a hair treatment composition) after step 1 (applying a cosmetic composition), and the cosmetic composition used in step 1 contains specific components (A) to (C) and has a viscosity of 1 to 30,000 mPa s at pH 4.1, thereby significantly improving scalp protection ability and reducing or mitigating damage to the scalp caused by the hair treatment composition. Furthermore, according to one embodiment of the present invention, the hair treatment method of the present invention not only significantly improves scalp protection ability but also maintains the intended hair treatment effect, and the cosmetic composition used can maintain a good balance between application ease and dripping resistance, improving convenience for the user.

[0054] More specifically, according to the present invention, the scalp is protected from damage caused by a hair color composition, a hair bleach composition, a perm composition, or a relaxer composition, and therefore an effect of effectively protecting the scalp can be obtained. In addition, in one embodiment of the present invention, the composition used in the present invention has good applicability, so that the user can easily and uniformly apply the composition to the scalp. Furthermore, since the composition has low dripping, an appropriate amount of the composition can provide an effect of protecting the scalp. In one embodiment of the present invention, the hair treatment method of the present invention does not reduce the hair treatment effect to be achieved, and can be well maintained. For example, when a hair color composition is applied, the dyeability of the hair color composition is not affected, so that the scalp is protected and excellent dyeability can be maintained.

[0055] In accordance with the above-mentioned embodiments, the present invention discloses a hair treatment method, a cosmetic composition for protecting the scalp, and a kit thereof. <1> A hair treatment method comprising the following steps 1 and 2, in which step 2 is carried out after step 1. (Step 1) A step of applying to the scalp a cosmetic composition containing the following components (A), (B), and (C) and having a viscosity of 1 to 30,000 mPa·s at pH 4.1: (A) a pH buffer; (B) an antioxidant; and (C) pH-responsive thickener (Step 2) A step of applying to the hair at least one hair treatment composition selected from a hair color composition, a hair bleach composition, a perm composition, and a relaxer composition. <2> The content of the component (A) in the cosmetic composition is more than 0.15% by mass relative to the entire cosmetic composition. <1> The hair treatment method according to claim 1. <3> The content of the surfactant in the cosmetic composition is less than 5.0% by mass. <1> or <2> The hair treatment method according to claim 1. <4> The total content of the component (A) and the component (B) in the cosmetic composition is 0.2% by mass or more and 6.0% by mass or less with respect to the entire cosmetic composition. <1> ~ <3> The hair treatment method according to any one of the above. <5> The mass ratio ((A) / (B)) of the component (A) to the component (B) is 1.0 or more and 8.0 or less. <1> ~ <4> The hair treatment method according to any one of the above. <6> The cosmetic composition further comprises a thickener (D) different from the component (C). <1> ~ <5> The hair treatment method according to any one of the above. <7> The component (D) is sodium stearoxy PG hydroxyethyl cellulose sulfonate. <6> The hair treatment method according to claim 1. <8> The viscosity of the cosmetic composition at pH 5.0 increases by 1.1 to 10 times compared to the viscosity of the cosmetic composition at pH 4.1. <1> ~ <7> The hair treatment method according to any one of the above. <9> The pH buffer has a buffering capacity at least between pH 4.5 and 5.5. <1> ~ <8> The hair treatment method according to any one of the above. <10> The pH buffer has a buffering capacity at least between pH 4.5 and 5.5 using an acid or a salt thereof having a pKa (25°C) of 4.0 to 6.5. <1> ~ <9> The hair treatment method according to any one of the above. <11> The pH buffer has a buffering capacity of at least pH 4.5 to 5.5 using at least one acid selected from barbituric acid, succinic acid, citric acid, acetic acid, malic acid, phthalic acid, and carbonic acid, and a salt thereof. <1> ~ <10> The hair treatment method according to any one of the above. <12> The pH buffer is preferably at least one selected from the group consisting of succinic acid and its salts, malic acid and its salts, and citric acid and its salts, more preferably contains citric acid and its salts, and further preferably contains citric acid and sodium citrate. <1> ~ <11> The hair treatment method according to any one of the above. <13> The total content of component (A) (in the case of conjugate acid-base pairs, the total content thereof) is preferably more than 0.15% by mass and not more than 10.0% by mass, more preferably from 0.2% by mass to 9.0% by mass, even more preferably from 0.5% by mass to 8.0% by mass, even more preferably from 1.0% by mass to 6.0% by mass, even more preferably from 1.0% by mass to 4.0% by mass, and even more preferably from 1.5% by mass to 4.0% by mass. <1> ~ <12> The hair treatment method according to any one of the above. <14> Component (B) is preferably one or more selected from the group consisting of dibutylhydroxytoluene, butylhydroxyanisole, δ-tocopherol, thiotaurine, thioglycolic acid, propanoic acid, tert-butylhydroquinone, nicotinic acid or a derivative thereof, catechin, evening primrose extract, β-carotene, a flavonoid compound, sulfurous acid or a salt thereof, ascorbic acid or a salt or derivative thereof, L-cysteine ​​or a salt or derivative thereof, N-acetyl-L-cysteine ​​or a salt or derivative thereof, and a polyphenol compound, and more preferably ascorbic acid. and more preferably, one or more selected from the group consisting of ascorbic acid or a salt thereof, ascorbic acid glucoside, magnesium ascorbic acid phosphate, erythorbic acid, sodium erythorbate, dibutylhydroxytoluene, and catechin, more preferably, one or more selected from the group consisting of ascorbic acid or a salt thereof, ascorbic acid glucoside, magnesium ascorbic acid phosphate, erythorbic acid, and sodium erythorbate, and even more preferably, one or more selected from the group consisting of ascorbic acid and ascorbic acid glucoside. <1> ~ <13> The hair treatment method according to any one of the above. <15> The total content of component (B) is preferably 0.01% by mass or more and 5.0% by mass or less, more preferably 0.1% by mass or more and 3.0% by mass or less, even more preferably 0.2% by mass or more and 1.5% by mass or less, even more preferably 0.2% by mass or more and 1.0% by mass or less, and even more preferably 0.2% by mass or more and 0.7% by mass or less. <1> ~ <14> The hair treatment method according to any one of the above. <16> The total content of component (A) and component (B) is preferably 0.2 mass% or more and 10.0 mass% or less, more preferably 1.0 mass% or more and 8.0 mass% or less, even more preferably 2.3 mass% or more and 6.0 mass% or less, even more preferably 2.3 mass% or more and 5.5 mass% or less, even more preferably 2.5 mass% or more and 5.0 mass% or less, even more preferably 2.5 mass% or more and 4.5 mass% or less, and even more preferably 2.5 mass% or more and 4.0 mass% or less. <1> ~ <15> The hair treatment method according to any one of the above. <17> The mass ratio of component (A) to component (B) (component (A) / component (B)) is preferably 1.0 or more and 8.0 or less, more preferably 1.1 or more and 7.5 or less, even more preferably 1.5 or more and 6.5 or less, even more preferably 2.0 or more and 6.0 or less, and even more preferably 3.0 or more and 5.0 or less. <1> ~ <16> The hair treatment method according to any one of the above. <18> The pH-responsive thickener is an ionic water-soluble polymer whose viscosity increases with increasing pH over a portion or all of the pH range of 3 to 7. <1> ~ <17> The hair treatment method according to any one of the above. <19> The pH-responsive thickener is an ionic water-soluble polymer that contains at least one group selected from an unneutralized carboxyl group and an unneutralized sulfonic acid group, and whose viscosity increases with increasing pH in a part or all of the pH range of 3 to 7. <1> ~ <18> The hair treatment method according to any one of the above. <20> The pH-responsive thickener is a linear or branched polymer having one or more selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, styrenesulfonic acid, vinylbenzoic acid, 2-acrylamido-2-methyl-1-propanesulfonic acid, and dimethylolpropionic acid, or a crosslinked polymer or copolymer thereof; <1> ~ <19> The hair treatment method according to any one of the above. <21> The pH responsive thickener is preferably one or more selected from the group consisting of polyacrylic acid, carboxyvinyl polymer, sodium polyacrylate, acrylic acid / alkyl methacrylate copolymer, polymethacrylic acid, and methacrylic acid / alkyl methacrylate copolymer, more preferably one or more selected from the group consisting of acrylic acid / alkyl methacrylate copolymer, methacrylic acid / alkyl methacrylate copolymer, and carboxyvinyl polymer, and further preferably contains carboxyvinyl polymer. <1> ~ <20> The hair treatment method according to any one of the above. <22> The total content of component (C) is preferably 0.1% by mass or more and 3.0% by mass or less, more preferably 0.1% by mass or more and 2.5% by mass or less, even more preferably 0.1% by mass or more and 2.0% by mass or less, even more preferably 0.2% by mass or more and 1.7% by mass or less, and even more preferably 0.2% by mass or more and 1.5% by mass or less. <1> ~ <21> The hair treatment method according to any one of the above. <23> The cosmetic composition further contains, as a thickener (D), one or more selected from the group consisting of nonionic water-soluble polymers and ionic water-soluble polymers that do not show an extreme change in viscosity at a pH range of 3 to 7. <1> ~ <22> The hair treatment method according to any one of the above. <24> Component (D) preferably contains one or more selected from the group consisting of xanthan gum, carrageenan, alginic acid, starch, hydroxycellulose, hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, stearoxy PG hydroxyethylcellulose sulfonate Na, carboxymethylcellulose sodium, methylcellulose, cationized cellulose, polyvinylpyrrolidone, polyvinyl alcohol, and cationized polyvinylpyrrolidone, more preferably contains one or more selected from the group consisting of xanthan gum, hydroxyethylcellulose, hydroxypropylcellulose, carboxymethylcellulose sodium, stearoxy PG hydroxyethylcellulose sulfonate Na, polyvinylpyrrolidone, and polyvinyl alcohol, and even more preferably contains one or more selected from the group consisting of stearoxy PG hydroxyethylcellulose sulfonate Na, xanthan gum, and hydroxyethylcellulose. <6> ~ <23> The hair treatment method according to any one of the above. <25> The total content of component (D) is preferably 0.1% by mass or more and 5.0% by mass or less, more preferably 0.1% by mass or more and 4.0% by mass or less, even more preferably 0.2% by mass or more and 3.0% by mass or less, and even more preferably 0.2% by mass or more and 2.5% by mass or less. <6> ~ <24> The hair treatment method according to any one of the above. <26> The total content of water-soluble solvents in the cosmetic composition is preferably 10.0% by mass or less, more preferably 5.0% by mass or less, even more preferably 4.0% by mass or less, even more preferably 3.0% by mass or less, even more preferably 2.0% by mass or less, even more preferably 1.0% by mass or less, and is substantially free of water-soluble solvents. <1> ~ <25> The hair treatment method according to any one of the above. <27> The content of water in the cosmetic composition is preferably 50% by mass or more and 99.8% by mass or less, and more preferably 60% by mass or more and 98% by mass or less. <1> ~ <26> The hair treatment method according to any one of the above. <28> The total content of surfactants in the cosmetic composition is preferably less than 5.0% by mass, more preferably less than 4.0% by mass, even more preferably less than 3.0% by mass, even more preferably less than 2.0% by mass, even more preferably less than 1.0% by mass, and even more preferably substantially free of surfactants. <1> ~ <27> The hair treatment method according to any one of the above. <29> the viscosity of the cosmetic composition at pH 4.1 is preferably 10 mPa·s or more and 30,000 mPa·s or less, more preferably 100 mPa·s or more and 30,000 mPa·s or less, even more preferably 300 mPa·s or more and 25,000 mPa·s or less, even more preferably 800 mPa·s or more and 20,000 mPa·s or less, even more preferably 800 mPa·s or more and 10,000 mPa·s or less, even more preferably 1500 mPa·s or more and 5000 mPa·s or less, and even more preferably 1500 mPa·s or more and 2500 mPa·s or less; <1> ~ <28> The hair treatment method according to any one of the above. <30> the viscosity of the cosmetic composition at pH 5.0 is preferably 1.1 to 9 times, more preferably 1.1 to 7 times, even more preferably 1.1 to 5 times, and even more preferably 1.1 to 3 times, compared with the viscosity of the cosmetic composition at pH 4.1; <1> ~ <29> The hair treatment method according to any one of the above. <31> the cosmetic composition further contains a pH adjuster, and the pH adjuster is preferably one or more selected from the group consisting of sodium hydroxide, potassium hydroxide, monoethanolamine, diethanolamine, triethanolamine, aminopropanol, ammonia, ammonium chloride, and arginine, and more preferably one or more selected from the group consisting of sodium hydroxide, potassium hydroxide, triethanolamine, and arginine; <1> ~ <30> The hair treatment method according to any one of the above. <32> The pH of the cosmetic composition is preferably 3.0 or more and 7.0 or less, more preferably 3.0 or more and 6.5 or less, even more preferably 3.5 or more and 6.0 or less, still more preferably 3.5 or more and 5.0 or less, and still more preferably 3.5 or more and 4.8 or less. <1> ~ <31> The hair treatment method according to any one of the above. <33> In the step 1, the amount of the cosmetic composition applied to the scalp is preferably 8 to 40 μl / cm 2 More preferably, in the range of 13 to 27 μl / cm 2 More preferably, the range is 20 to 27 μl / cm 2 In the range of <1> ~ <32> The hair treatment method according to any one of the above. <34> A cosmetic composition for protecting the scalp, comprising the following components (A), (B), and (C), and having a viscosity of 1 to 30,000 mPa·s at pH 4.1: (A) a pH buffer; (B) an antioxidant; and (C) pH-responsive thickener <35> The pH buffer has a buffering capacity at least between pH 4.5 and 5.5. <34> The cosmetic composition according to claim 1. <36> Contains the following components (A), (B) and (C), Component (A) has a buffering capacity at least between pH 4.5 and 5.5 using an acid or a salt thereof having a pKa (25°C) of 4.0 to 6.5; Component (B) is at least one selected from the group consisting of ascorbic acid or a salt thereof, ascorbic acid glucoside, magnesium ascorbyl phosphate, erythorbic acid, and sodium erythorbate; Component (C) is an ionic water-soluble polymer that contains at least one group selected from an unneutralized carboxyl group and an unneutralized sulfonic acid group, and whose viscosity increases with increasing pH over a portion or all of the pH range of 3 to 7; The cosmetic composition has a pH of 3.5 or more and 4.8 or less; A cosmetic composition for protecting the scalp, having a viscosity of 100 to 30,000 mPa·s at pH 4.1. <37> Contains the following components (A), (B) and (C), Component (A) has a buffering capacity at least between pH 4.5 and 5.5 using an acid or a salt thereof having a pKa (25°C) of 4.0 to 6.5; Component (B) is at least one selected from the group consisting of ascorbic acid or a salt thereof, ascorbic acid glucoside, magnesium ascorbyl phosphate, erythorbic acid, and sodium erythorbate; Component (C) is an ionic water-soluble polymer that contains at least one group selected from an unneutralized carboxyl group and an unneutralized sulfonic acid group, and whose viscosity increases with increasing pH over a portion or all of the pH range of 3 to 7; The cosmetic composition has a pH of 3.5 or more and 4.8 or less; The surfactant content is less than 1.0% by mass, A cosmetic composition for protecting the scalp, having a viscosity of 100 to 30,000 mPa·s at pH 4.1. <38> The content of the component (A) in the cosmetic composition is more than 0.15% by mass, and the content of the surfactant in the cosmetic composition is less than 5.0% by mass, based on the entire cosmetic composition. <34> ~ <36> 13. The cosmetic composition according to any one of claims 1 to 12. <39> the content of the component (A) in the cosmetic composition is more than 0.15% by mass, the total content of the component (A) and the component (B) in the cosmetic composition is 2.3% by mass or more and 6.0% by mass or less, based on the entire cosmetic composition, and the content of a surfactant is less than 5.0% by mass; <34> ~ <36> 13. The cosmetic composition according to any one of claims 1 to 12. <40> (I) a cosmetic composition containing the following components (A), (B), and (C) and having a viscosity of 1 to 30,000 mPa s at pH 4.1; (A) pH buffer, (B) an antioxidant; (C) pH-responsive thickener (II) Hair color composition, hair bleach composition, perm composition and relaxer composition and at least one hair treatment composition selected from the group consisting of: <41> The pH buffer has a buffering capacity at least between pH 4.5 and 5.5. <40> The kit according to claim 1, EXAMPLES

[0056] The present invention will be described below with reference to examples, but the present invention is not limited to the scope of the examples. In the examples, various measurements and evaluations were carried out by the following methods.

[0057] (pH measurement) The pH of the stock solution was measured at 25° C. using a pH meter (pH METER F-52, manufactured by Horiba, Ltd.).

[0058] (viscosity measurement) In the present invention, the viscosity is measured at 25° C. using a B-type viscometer (VISCOMETER TVB-10; manufactured by Toki Sangyo Co., Ltd.) and refers to the value after rotating for 10 seconds. The rotor and rotation speed used during measurement are selected according to the viscosity of the cosmetic composition, and appropriate conditions are selected in accordance with the manual for the measuring device, etc., and examples of the conditions include the following: Less than 200 mPa·s = Rotor No. 1, 30 rpm, 200 mPa·s or more but less than 4000 mPa·s = Rotor No. 3, 30 rpm, 4000 mPa·s or more but less than 20000 mPa·s = Rotor No. 4, 30 rpm, 20000mPa·s or more but less than 50000mPa·s = Rotor No. 4, 12 rpm

[0059] (Evaluation of scalp protection ability) Pigskin (Funakoshi Co., Ltd.) was washed with shampoo (as shown in Table 1 below), thoroughly dried, and 20 μl of a cosmetic composition sample (hereinafter referred to as "sample") was spread over a 1.5 cm square. 100 μl of hair bleach (as shown in Table 2 below; agent 1 and agent 2 were mixed 1:1 during evaluation) was then applied from above, left at room temperature for 30 minutes, rinsed with water at about 40°C for 30 seconds, and dried. After thorough drying, a 1.5 cm square tape (acrylic tape; Teraoka Seisakusho Co., Ltd.) was attached to the sample-treated area, tape stripping was performed three times, and the stratum corneum was collected from the adhesive surface of the tape. Each tape was cut into four pieces, placed in a vial, and 450 μl of a mixed aqueous solution of 0.1 N NaOH and 1% sodium dodecyl sulfate was added, and protein extraction was performed for 2.5 hours in a 60°C incubator. After cooling with water, 50 μl of 2N HCl was added to prepare a stratum corneum protein extract sample. The stratum corneum protein was quantified using a BCA protein assay kit (Thermo Fisher Scientific). 20 μl each of the included standard solution and stratum corneum protein extract sample were placed in a 96-well plate, and 200 μl of the included color development solution (A:B mixed at 50:1) was added, and the plate was incubated in a 37°C incubator for 30 minutes. The absorbance at 562 nm was measured using a microplate reader (Sunrise Rainbow Thermo; RC-R, Tencan), and the amount of stratum corneum protein in the extract was calculated from the calibration curve of the standard solution. The scalp protection ability was calculated using the following formula (1), with a higher value indicating a higher scalp protection ability.

[0060]

number

[0061] [Table 1]

[0062] [Table 2]

[0063] (Evaluation of dyeability) 350 mg of the sample was spread over the entire surface of 1 g of Chinese gray hair tresses (manufactured by Beaulax), and immediately thereafter, a hair coloring agent (Blone Foam Color 4: Light Brown; manufactured by Kao Corporation) was applied to a 1 g bundle of gray hair at a bath ratio of 0.7, and the hair was left to stand at 30°C for 20 minutes, then rinsed with water at approximately 40°C, washed with the shampoo in Table 1 above, and washed with water. Next, a hair rinse (as shown in Table 3 below) was applied, followed by rinsing with water at approximately 40°C, wiping with a towel, and drying with a hair dryer. The resulting color tone of the bundle of hair immediately after dyeing was measured using a color difference meter (manufactured by Konica Minolta Sensing Co., Ltd.; color difference meter CR-400) in accordance with the CIE color system (L * ,a * ,b * ) and the difference in color between the sample and the untreated dyed hair bundle was calculated using the following formula (2) to determine the dyeability ΔE * It was decided. * 0, a * 0 and b * 0 is the L of the dyed hair bundle without sample treatment. * , a * and b * indicates the value of L * 1, a * 1 and b * 1 is the L immediately after dyeing the hair bundles that were dyed after sample treatment. * , a * and b * The value of ΔE is shown. * The smaller the value, the less the sample affects the hair dyeability.

[0064]

number

[0065] [Table 3]

[0066] (Evaluation of Coatability) A 20 ml sample was placed in a PETG ampoule container (manufactured by Pin Mao Plastics Industry Co., Ltd.; volume: approximately 20 ml), and 0.72 g was applied from the container to a scalp sample with hair growing in an area of ​​6 cm square (the scalp sample had a rubber dressing manufactured by Beaulux). The sample was then massaged with the fingers for 10 seconds and the ease of spreading was evaluated on a 6-point scale. 6. Very easy to spread 5. Easy to spread 4. Somewhat easy to spread 3. Normal 2. Somewhat difficult to spread 1. Hard to spread

[0067] (Evaluation of dripping property) A 0.2 ml droplet (1 cm in diameter) of each sample was placed on a polypropylene sheet, tilted 90 degrees, and the distance the liquid dripped was measured after 30 seconds.

[0068] (Examples 1 to 43, Comparative Examples 1 to 4) Each cosmetic composition was prepared based on the composition shown in Tables 4 to 9 and evaluated according to the above-mentioned method. The numerical values ​​for components (A), (B), (C), and (D) shown in Tables 4 to 9 indicate the active amount of each component in each composition, expressed as mass %.

[0069] [Table 4] [Table 5] [Table 6] [Table 7] [Table 8] [Table 9] *16: Ascorbic acid, manufactured by Watanabe Chemical Co., Ltd. *17: BHT, manufactured by Nikki Universal Co., Ltd. *18: Nicotinic acid dl-α-tocopherol, manufactured by Joko Pharmaceutical Co., Ltd. *19: Refined anhydrous sodium sulfite, manufactured by Daito Chemical Co., Ltd. *20: ADEKA Corporation, DPG-RF *21: NEOLONE PH 100, manufactured by The Dow Chemical Company *22: PUROX S, manufactured by Emerald Kalama Chemical, BV

[0070] According to the above table, in comparison with Comparative Examples 1 to 3 in which no pH buffer, antioxidant, or pH-responsive thickener was added to the cosmetic composition used, or Comparative Example 4 in which the viscosity of the cosmetic composition used at pH 4.1 exceeds 30,000 mPa·s, the cosmetic compositions used in Examples 1 to 43 of the present invention simultaneously contain a pH buffer, an antioxidant, and a pH-responsive thickener, and the viscosity of the cosmetic composition at pH 4.1 is set to 1 to 30,000 mPa·s, and the cosmetic composition is applied before hair treatment, thereby significantly improving the scalp protection ability. Moreover, according to the compositions of all the examples of the present invention, not only is the scalp protection ability significantly improved, but an excellent dyeing effect can be maintained, and a good balance between application and dripping can be maintained.

[0071] As can be seen from Comparative Examples 1 to 3, in comparison with the examples of the present invention, when the composition used does not contain any of a pH buffer, an antioxidant, and a pH-responsive thickener, the scalp protection ability is reduced. As can be seen from Comparative Example 4, when the viscosity of the composition used at pH 4.1 exceeds 30,000 mPa·s, the applicability is poor, which not only causes inconvenience to the user, but also reduces the scalp protection ability because the composition cannot be applied uniformly over the entire scalp. [Industrial Applicability]

[0072] The hair treatment method of the present invention can be suitably used in the field of cosmetics, etc. Also, it is suitable for animals such as dogs and cats as well as humans.

Claims

1. A hair treatment method comprising the following steps 1 and 2, in which step 2 is carried out after step 1. (Step 1) The composition contains the following components (A), (B), and (C), in which the mass ratio of component (A) to component (B) ((A) / (B)) is 2.0 or more and 6.0 or less, and the viscosity at pH 4.1 is 1 to 30,000 mPa·s. Applying the cosmetic composition to the scalp (A) 0.5 to 6.0% by mass of a pH buffer which is a combination of one or more selected from succinic acid and its salts, malic acid and its salts, and citric acid and its salts, (B) 0.01 to 1.5% by mass of one or more antioxidants selected from ascorbic acid or a salt thereof, ascorbic acid glucoside, dibutylhydroxytoluene, tocopherol nicotinate, sodium sulfite, and catechin; (C) one or more pH-responsive thickeners selected from acrylic acid / alkyl methacrylate copolymers, methacrylic acid / alkyl methacrylate copolymers, and carboxyvinyl polymers; 0.08-1.5% by mass (Step 2) A step of applying to the hair at least one hair treatment composition selected from a hair color composition, a hair bleach composition, a perm composition, and a relaxer composition.

2. The hair treatment method according to claim 1 , wherein the content of the surfactant in the cosmetic composition is less than 5.0% by mass.

3. The hair treatment method according to claim 1 or 2, wherein the total content of the component (A) and the component (B) in the cosmetic composition is 0.74% by mass or more and 6.0% by mass or less with respect to the total amount of the cosmetic composition.

4. The hair treatment method according to any one of claims 1 to 3, wherein the cosmetic composition further comprises a thickener (D) different from the component (C).

5. 5. The hair treatment method according to claim 4, wherein the component (D) is sodium stearoxy PG hydroxyethyl cellulose sulfonate.

6. The hair treatment method according to any one of claims 1 to 5, wherein the viscosity of the cosmetic composition at pH 5.0 increases 1.1 to 10 times compared to the viscosity of the cosmetic composition at pH 4.

1.

7. A cosmetic composition for protecting the scalp, comprising the following components (A), (B), and (C), in which the mass ratio of component (A) to component (B) ((A) / (B)) is 2.0 or more and 6.0 or less, and the viscosity at pH 4.1 is 1 to 30,000 mPa·s. (A) 0.5 to 6.0% by mass of a pH buffer which is a combination of one or more selected from succinic acid and its salts, malic acid and its salts, and citric acid and its salts, (B) 0.01 to 1.5% by mass of one or more antioxidants selected from ascorbic acid or a salt thereof, ascorbic acid glucoside, dibutylhydroxytoluene, tocopherol nicotinate, sodium sulfite, and catechin; (C) one or more pH-responsive thickeners selected from acrylic acid / alkyl methacrylate copolymers, methacrylic acid / alkyl methacrylate copolymers, and carboxyvinyl polymers; 0.08-1.5% by mass

8. (I) a cosmetic composition comprising the following components (A), (B), and (C), in which the mass ratio of component (A) to component (B) ((A) / (B)) is 2.0 or more and 6.0 or less, and the viscosity at pH 4.1 is 1 to 30,000 mPa s; (A) 0.5 to 6.0% by mass of a pH buffer which is a combination of one or more selected from succinic acid and its salts, malic acid and its salts, and citric acid and its salts, (B) 0.01 to 1.5% by mass of one or more antioxidants selected from ascorbic acid or a salt thereof, ascorbic acid glucoside, dibutylhydroxytoluene, tocopherol nicotinate, sodium sulfite, and catechin; (C) one or more pH-responsive thickeners selected from acrylic acid / alkyl methacrylate copolymers, methacrylic acid / alkyl methacrylate copolymers, and carboxyvinyl polymers; 0.08-1.5% by mass (II) At least one hair treatment composition selected from the group consisting of a hair color composition, a hair bleach composition, a perm composition, and a relaxer composition.

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