Hair dyeing method

Abstract

Provided is a method for dyeing hair, which comprises, in this order, a step (I) for preparing a hair dye composition by mixing, prior to use, an agent A containing the following component (A1) and a component (A2) with an agent B: (A1) a compound represented by general formula (1) or a salt thereof. The dashed line represents the presence or absence of a pi bond; r1 represents a hydroxyl group or an acetoxy group; r2 represents a hydrogen atom, or-COOR (R is a hydrogen atom, methyl or ethyl); r3 represents a hydrogen atom, an acetyl group, a methyl group or an ethyl group]; (A2) an alkaline agent; the agent B contains the following component (B1) and component (B2): (B1) an oxidation dye other than the component (A1); (B2) an alkaline agent; step (II): a step for applying the hair dye composition to hair, and the mixing ratio of the agent A and the agent B in step (I) being a specific ratio # imgabs0

Description

Technical Field

[0001] The present invention relates to a method for dyeing hair. Background Art

[0002] From the viewpoint of suppressing damage to hair, there is a demand for hair dyeing technology that does not use an oxidizing agent such as hydrogen peroxide.

[0003] Air-oxidation hair dye compositions are known that use melanin precursors such as 5,6-dihydroxyindole, 5,6-dihydroxyindoline, or their derivatives (hereinafter collectively referred to as "dihydroxyindole derivatives") as coloring ingredients for dyeing gray hair. These melanin precursors are components that convert to melanin through oxidative polymerization, but they can also undergo oxidative polymerization through air oxidation. Therefore, even when used in hair dye compositions, they minimize hair damage and offer high convenience as coloring ingredients.

[0004] Since hair dyed with melanin precursors generally appears gray to black, the range of color expression is extremely limited when using only melanin precursors as coloring components. Therefore, hair dyes and hair dyeing methods that use dihydroxyindole derivatives and oxidation dyes in combination have been studied.

[0005] For example, Japanese Patent Laid-Open No. 3-58917 (Patent Document 1) discloses a method for dyeing keratinous fibers, characterized in that, in a first step, a composition (A) containing a specific indole dye, an addition salt thereof with an inorganic acid or organic acid, and an alkali metal salt, alkaline earth metal salt, or a corresponding amine salt in a medium suitable for dyeing without containing an oxidizing agent is applied to keratinous fibers, particularly human keratinous fibers. In a second step, a composition (B) containing a specific oxidative dye in a medium suitable for dyeing is applied to the keratinous fibers. Furthermore, when using composition (B), hydrogen peroxide is mixed as needed.

[0006] Japanese Patent Application Laid-Open No. 1-252673 (Patent Document 2), Japanese Patent Application Laid-Open No. 3-58916 (Patent Document 3), Japanese Patent Application Laid-Open No. 4-295414 (Patent Document 4), Chinese Patent Application Publication No. 114177114 (Patent Document 5), and Japanese Patent Translation No. 2001-511436 (Patent Document 6) disclose methods for dyeing hair using a one-component hair dye containing a dihydroxyindole derivative and various oxidation dyes. Summary of the Invention

[0007] The present invention relates to the following.

[0008] [1] A method for dyeing hair, comprising the steps (I) and (II) in this order, and not comprising the step of applying an oxidizing agent to the hair.

[0009] Step (I): A step of preparing a hair dye composition by mixing Agent A and Agent B before use.

[0010] The agent A contains the following ingredients (A1) and (A2):

[0011] (A1) a compound represented by the following general formula (1) or a salt thereof,

[0012]

[0013] [Wherein, the dotted line indicates the presence or absence of a π bond; R 1 represents a hydroxyl group or an acetoxy group; R 2 represents a hydrogen atom, or -COOR (R is a hydrogen atom, a methyl group or an ethyl group); R 3 represents a hydrogen atom, an acetyl group, a methyl group or an ethyl group;]

[0014] (A2) alkali agent;

[0015] The B agent contains the following ingredients (B1) and (B2):

[0016] (B1) oxidation dyes other than the component (A1);

[0017] (B2) alkali agent;

[0018] Step (II): a step of applying the hair dye composition to hair, and

[0019] The mixing ratio of the agent A and the agent B in the step (I) is such that the molar ratio of the component (A1) to the component (B1) [(A1) / (B1)] is 10 / 90 to 70 / 30.

[0020] [2] A hair dyeing set comprising an agent A and an agent B, and excluding a preparation containing an oxidizing agent,

[0021] Agent A contains the following ingredients (A1) and (A2):

[0022] (A1) a compound represented by the following general formula (1) or a salt thereof,

[0023]

[0024] [Wherein, the dotted line indicates the presence or absence of a π bond; R 1 represents a hydroxyl group or an acetoxy group; R 2represents a hydrogen atom, or -COOR (R is a hydrogen atom, a methyl group or an ethyl group); R 3 represents a hydrogen atom, an acetyl group, a methyl group or an ethyl group;]

[0025] (A2) alkali agent;

[0026] Agent B contains the following ingredients (B1) and (B2):

[0027] (B1) oxidation dyes other than the above-mentioned component (A1);

[0028] (B2) Alkaline agent. DETAILED DESCRIPTION

[0029] Because the method disclosed in Patent Document 1 involves applying a composition containing a specific indole dye or its salt to keratinous fibers in the first stage and a composition containing a specific oxidation dye to keratinous fibers in the second stage, it requires at least two steps. This makes the dyeing process time-consuming, and differences in bath ratios and step intervals can make it difficult to achieve the desired color tone. Furthermore, hydrogen peroxide is essentially required in the second stage, raising concerns about hair damage.

[0030] Since the methods disclosed in Patent Documents 2 to 6 all use one-dose hair dyes, in order to improve hair dyeing properties and achieve a variety of color expressions, it is necessary to prepare a plurality of one-dose hair dyes and mix them when using them, which is a relatively complicated operation.

[0031] The present invention relates to a hair dyeing method using a melanin precursor, which method causes less hair damage due to dyeing, has excellent hair dyeing properties, and can easily achieve a variety of color expressions.

[0032] The present inventors have discovered that the above-mentioned problems can be solved by a hair dyeing method comprising the steps of preparing a hair dye composition by mixing an agent A containing a melanin precursor and an alkali agent and an agent B containing an oxidation dye and an alkali agent in a specific ratio before use, and applying the hair dye composition to the hair, without the step of applying an oxidizing agent to the hair.

[0033] According to the present invention, there is provided a hair dyeing method using a melanin precursor, which causes less hair damage due to dyeing, has excellent hair dyeing properties, and can easily achieve a variety of color expressions.

[0034] [definition]

[0035] In this specification, "good hair dyeing properties" means a high degree of hair dyeing. "High degree of hair dyeing" means a large color difference (ΔE) between the hair before and after dyeing. Specifically, ΔE can be evaluated by the method described in the Examples.

[0036] As used herein, "easy to achieve a variety of color expressions" means that the color can be easily changed by simply varying the ratio of Agent A and Agent B, the materials of the hair dye composition, without adding multiple hair dyes. Furthermore, the variety of color expressions can be evaluated using the difference (ΔC) in the chroma C value when treating with Agents A and B individually and when treating with a mixture, using the following method.

[0037] [Hair dyeing method]

[0038] The hair dyeing method of the present invention (hereinafter also referred to as "the hair dyeing method of the present invention" or simply "the method of the present invention") comprises steps (I) and (II) in this order and does not comprise a step of applying an oxidizing agent to the hair.

[0039] Step (I): A step of preparing a hair dye composition by mixing Agent A and Agent B before use.

[0040] The agent A contains the following ingredients (A1) and (A2):

[0041] (A1) a compound represented by the following general formula (1) or a salt thereof,

[0042]

[0043] [Wherein, the dotted line indicates the presence or absence of a π bond; R 1 represents a hydroxyl group or an acetoxy group; R 2 represents a hydrogen atom, or -COOR (R is a hydrogen atom, a methyl group or an ethyl group); R 3 represents a hydrogen atom, an acetyl group, a methyl group or an ethyl group;]

[0044] (A2) alkali agent;

[0045] The B agent contains the following ingredients (B1) and (B2):

[0046] (B1) oxidation dyes other than the component (A1);

[0047] (B2) alkali agent;

[0048] Step (II): a step of applying the hair dye composition to hair, and

[0049] The mixing ratio of the agent A and the agent B in the step (I) is such that the molar ratio of the component (A1) to the component (B1) [(A1) / (B1)] is 10 / 90 to 70 / 30.

[0050] In this specification, in order to easily express a variety of colors, as described above, it is only necessary to change the ratio of agent A and agent B, which are the materials of the hair dye composition, and mix them, without the need to use multiple hair dyes. On the other hand, the well-known ordinary two-part hair dye contains 1 agent (dye and alkali agent) and 2 agents (hydrogen peroxide), which are mixed in a certain ratio, so only one color can be expressed. Moreover, even if the ratio is changed, only the depth of the dyeing can be changed. In order to use this hair dye to express a variety of colors, it is necessary to use another agent when using it.

[0051] The hair dyeing method of the present invention has the above-mentioned configuration, thereby causing less hair damage due to dyeing, achieving excellent hair dyeing properties, and easily achieving various color expressions even when the component (A1) which is a melanin precursor is used as a coloring component.

[0052] The reason why the present invention exhibits the above-mentioned effects is considered as follows.

[0053] The method of the present invention is different from the method using a one-part hair dye composition. Agent A and Agent B are mixed before use. Therefore, the desired color can be easily achieved by changing the mixing ratio of Agent A and Agent B.

[0054] By adjusting the mixing ratio of Agent A and Agent B so that the molar ratio [(A1) / (B1)] falls within a specific range, a variety of colors can be expressed even when using Component (A1), which typically exhibits gray to black, as a coloring component. Furthermore, it is believed that even without using an oxidizing agent in the hair dyeing process, sufficient hair dyeing properties can be achieved through air oxidation, thereby suppressing hair damage.

[0055] <Step (I)>

[0056] In step (I), Agent A and Agent B are mixed before use to prepare a hair dye composition, wherein Agent A contains the following components (A1) and (A2):

[0057] (A1) a compound represented by the following general formula (1) or a salt thereof,

[0058]

[0059] [Wherein, the dotted line indicates the presence or absence of a π bond; R 1 represents a hydroxyl group or an acetoxy group; R 2 represents a hydrogen atom, or -COOR (R is a hydrogen atom, a methyl group or an ethyl group); R3 represents a hydrogen atom, an acetyl group, a methyl group or an ethyl group;]

[0060] (A2) alkali agent;

[0061] The above-mentioned agent B contains the following ingredients (B1) and (B2):

[0062] (B1) oxidation dyes other than the above-mentioned component (A1);

[0063] (B2) Alkaline agent.

[0064] (Dose A)

[0065] Agent A used in step (I) contains the following components (A1) and (A2):

[0066] (A1) a compound represented by the following general formula (1) or a salt thereof,

[0067]

[0068] [Wherein, the dotted line indicates the presence or absence of a π bond; R 1 represents a hydroxyl group or an acetoxy group; R 2 represents a hydrogen atom, or -COOR (R is a hydrogen atom, a methyl group or an ethyl group); R 3 represents a hydrogen atom, an acetyl group, a methyl group or an ethyl group;]

[0069] (A2) Alkaline agent.

[0070] [Component (A1): a compound represented by the general formula (1) or a salt thereof]

[0071] Agent A contains component (A1) which is a compound represented by the above-mentioned general formula (1) or a salt thereof. Component (A1) is a melanin precursor that is polymerized by air oxidation and converted into melanin, and functions as a hair dye.

[0072] The compound represented by the general formula (1) is an indole derivative or an indoline derivative, or a salt thereof, and in the present invention, one kind or a combination of two or more kinds thereof can be used.

[0073] From the viewpoint of improving hair dyeing properties and facilitating the expression of various colors, component (A1) is more preferably an indole derivative (ie, a π bond exists in the dotted line portion in general formula (1)).

[0074] From the viewpoint of improving the availability and hair dyeing properties of component (A1) and the ease of expressing various colors, in the general formula (1), R 1 Preferably, hydroxyl group, R 2It is preferably a hydrogen atom or -COOR (R is a hydrogen atom, a methyl group or an ethyl group), and more preferably a hydrogen atom or -COOH. 3 Preferred is a hydrogen atom.

[0075] Examples of the compound represented by the general formula (1) include 5,6-dihydroxyindole, 5,6-dihydroxyindole-2-carboxylic acid, 5,6-dihydroxyindole-2-carboxylic acid methyl ester, 5,6-dihydroxyindole-2-carboxylic acid ethyl ester, N-methyl-5,6-dihydroxyindole, N-methyl-5,6-dihydroxyindole-2-carboxylic acid, N-ethyl-5,6-dihydroxyindole, N-ethyl-5,6-dihydroxyindole-2-carboxylic acid, N-acetyl-5,6-dihydroxyindole, N-acetyl-5,6-dihydroxyindole-2-carboxylic acid, 5-acetoxy-6-hydroxyindole, 5-acetoxy-6-hydroxyindole-2-carboxylic acid, 5,6 -dihydroxyindoline, 5,6-dihydroxyindoline-2-carboxylic acid, methyl 5,6-dihydroxyindoline-2-carboxylate, ethyl 5,6-dihydroxyindoline-2-carboxylate, N-methyl-5,6-dihydroxyindoline, N-methyl-5,6-dihydroxyindoline-2-carboxylic acid, N-ethyl-5,6-dihydroxyindoline, N-ethyl-5,6-dihydroxyindoline-2-carboxylic acid, N-acetyl-5,6-dihydroxyindoline, N-acetyl-5,6-dihydroxyindoline-2-carboxylic acid, 5-acetoxy-6-hydroxyindoline, 5-acetoxy-6-hydroxyindoline-2-carboxylic acid, and the like, one or more of which can be used.

[0076] Examples of salts of the compound represented by general formula (1) include hydrochlorides, hydrobromides, sulfates, phosphates, acetates, propionates, lactates, citrates, etc. Hydrobromides are preferred from the perspectives of improving availability and hair dyeing properties and facilitating the expression of various colors.

[0077] Furthermore, in the general formula (1), R 2 In the case of -COOH, examples of the salt of the compound represented by the general formula (1) include carboxylates (R 2 -COO - X + (X + for Na + , K + Alkali metal ions, Ca + Mg + alkaline earth metal ions, ammonium ions and other cations)).

[0078] From the viewpoint of improving hair dyeing properties and facilitating the expression of various colors, component (A1) is preferably one or more selected from 5,6-dihydroxyindole, 5,6-dihydroxyindole-2-carboxylic acid, 5,6-dihydroxyindoline, 5,6-dihydroxyindole-2-carboxylic acid, and salts thereof, more preferably one or more selected from 5,6-dihydroxyindole, 5,6-dihydroxyindole-2-carboxylic acid, and 5,6-dihydroxyindoleline hydrobromide, further preferably one or more selected from 5,6-dihydroxyindole and 5,6-dihydroxyindole-2-carboxylic acid, further more preferably containing 5,6-dihydroxyindole, and further more preferably containing 5,6-dihydroxyindole and 5,6-dihydroxyindole-2-carboxylic acid.

[0079] When component (A1) contains 5,6-dihydroxyindole and 5,6-dihydroxyindole-2-carboxylic acid, the molar ratio of 5,6-dihydroxyindole to 5,6-dihydroxyindole-2-carboxylic acid is preferably in the range of 50:50 to 99:1, more preferably in the range of 80:20 to 99:1, and even more preferably in the range of 85:15 to 95:5, from the viewpoint of improving hair dyeing properties and facilitating the expression of various colors.

[0080] When component (A1) contains 5,6-dihydroxyindole and 5,6-dihydroxyindole-2-carboxylic acid, the molar ratio of 5,6-dihydroxyindole to 5,6-dihydroxyindole-2-carboxylic acid in component (A1) can be quantified by reverse phase HPLC.

[0081] The content of component (A1) in agent A is preferably 0.02% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.1% by mass or more, from the viewpoint of improving hair dyeing properties and facilitating the expression of various colors. From the viewpoint of the degree of freedom in formulation, it is preferably 5.0% by mass or less, more preferably 3.0% by mass or less, even more preferably 2.0% by mass or less, even more preferably 1% by mass or less, even more preferably 0.8% by mass or less, and even more preferably 0.5% by mass or less.

[0082] [Ingredient (A2): Alkaline agent]

[0083] Component (A2) has a function of swelling the hair and opening the cuticle, thereby allowing coloring ingredients such as component (A1) to penetrate into the hair, thereby improving hair dyeing properties.

[0084] Component (A2) is not particularly limited as long as it is an alkali agent commonly used in hair dye compositions, and may be either an inorganic alkali agent or an organic alkali agent. Component (A2) is preferably ammonia or an organic alkali agent from the viewpoint of improving hair dyeing properties.

[0085] Preferred alkali agents as component (A2) include ammonia; alkanolamines such as monomethanolamine, dimethanolamine, trimethanolamine, monoethanolamine, diethanolamine, triethanolamine, trishydroxymethylaminomethane, and 2-amino-2-methyl-1-propanol; alkylamines such as methylamine, dimethylamine, ethylamine, diethylamine, N-methylethylamine, propylamine, and butylamine; and aralkylamines such as benzylamine. One or more of these can be used. From the perspective of water solubility, the number of carbon atoms in the alkanolamine, alkylamine, or aralkylamine is preferably 1 to 10, and more preferably 1 to 8.

[0086] Among the above, from the perspective of improving hair dyeing properties and facilitating the expression of various colors, component (A2) preferably contains one or more selected from ammonia, alkanolamines, alkylamines, and aralkylamines, more preferably contains one or more selected from ammonia and alkanolamines, and even more preferably contains alkanolamines. Among the alkanolamines, from the perspective of improving hair dyeing properties and facilitating the expression of various colors, component (A2) preferably contains one or more selected from monoethanolamine, trishydroxymethylaminomethane, and 2-amino-2-methyl-1-propanol, more preferably contains one or more selected from monoethanolamine and 2-amino-2-methyl-1-propanol, and even more preferably contains monoethanolamine.

[0087] From the viewpoint of improving hair dyeing properties and facilitating the expression of various colors, the content of the alkanolamine in component (A2) is preferably 70% by mass or more, more preferably 80% by mass or more, and still more preferably 90% by mass or more, and is 100% by mass or less.

[0088] The content of component (A2) in agent A is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.5% by mass or more, even more preferably 1.0% by mass or more, and even more preferably 2.0% by mass or more, from the viewpoint of allowing component (A1) to penetrate into the hair and promoting the polymerization reaction of component (A1) in the hair to improve hair dyeing properties. From the viewpoint of suppressing hair damage, the content is preferably 10% by mass or less, more preferably 7.5% by mass or less, and even more preferably 5.0% by mass or less.

[0089] [Ingredient (A3): Antioxidant]

[0090] From the viewpoint of suppressing the oxidative polymerization of the component (A1) outside the hair, the agent A preferably further contains an antioxidant as the component (A3).

[0091] Examples of the antioxidant include sulfurous acid, pyrosulfurous acid, hydrogen sulfite, sulfur dioxide, L-ascorbic acid, thioglycolic acid, L-cysteine, N-acetyl-L-cysteine, and salts and derivatives thereof. Examples of the salt include alkali metals such as sodium and potassium.

[0092] Among the above, from the viewpoint of the inhibitory effect of oxidative polymerization of component (A1) outside the hair, the antioxidant is preferably one or more selected from sulfites, pyrosulfites, bisulfites, sulfur dioxide, L-ascorbic acid, and L-ascorbic acid salts, more preferably one or more selected from sodium sulfite and sodium L-ascorbate, and even more preferably sodium sulfite.

[0093] When Agent A contains an antioxidant (A3), from the viewpoint of enhancing the effect of inhibiting the oxidative polymerization of Component (A1) outside the hair, the content of Component (A3) in Agent A is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more, even more preferably 0.2% by mass or more, and is preferably 10% by mass or less, more preferably 5.0% 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, even more preferably 0.5% by mass or less.

[0094] When Agent A contains an antioxidant (A3), the mass ratio of component (A3) to component (A1) in Agent A [(A3) / (A1)] is preferably 0.05 or more, more preferably 0.1 or more, even more preferably 0.2 or more, even more preferably 0.3 or more, even more preferably 0.5 or more, even more preferably 0.8 or more, even more preferably 1.0 or more, even more preferably 1.2 or more, from the viewpoint of improving hair dyeing properties. Furthermore, from the viewpoint of improving hair dyeing properties, it is preferably 10 or less, more preferably 5.0 or less, even more preferably 3.0 or less, even more preferably 2.0 or less.

[0095] [pH adjuster]

[0096] From the viewpoint of adjusting the pH value to the desired range described below, promoting the polymerization reaction of the component (A1) in the hair, and improving the hair dyeing properties, it is preferred that Agent A further contain a pH adjuster.

[0097] Since Agent A contains an alkaline agent as component (A2), the pH adjuster used in Agent A is preferably a protonating agent. The protonating agent can be either a monobasic acid or a polybasic acid, and can be either an organic acid (having 1 to 8 carbon atoms, excluding ascorbic acid) or an inorganic acid.

[0098] Examples of the protonating agent include one or more selected from hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid, and citric acid. From the perspective of adjusting the pH of Agent A to the following range, one or more selected from phosphoric acid and citric acid are preferred.

[0099] When Agent A contains a pH adjuster, from the viewpoint of adjusting the pH value of Agent A to the following range, the content of the pH adjuster in Agent A is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.2% by mass or more, and is preferably 5.0% by mass or less, more preferably 4.0% by mass or less, even more preferably 3.5% by mass or less, even more preferably 2.5% by mass or less, and even more preferably 1.5% by mass or less.

[0100] [Aqueous medium]

[0101] Agent A typically further contains an aqueous medium. Examples of the aqueous medium include water; lower alcohols such as ethanol and isopropyl alcohol; and low-molecular-weight diols and triols having 6 or fewer carbon atoms, such as 1,3-butylene glycol, glycerol, ethylene glycol, and propylene glycol. From the perspective of solubility of component (A1) and component (A2), affinity for hair, and suppression of hair damage, the aqueous medium is preferably one or more selected from water and ethanol, and more preferably water.

[0102] The content of the aqueous medium in Agent A is generally in the range of 1 to 99% by mass and can be appropriately selected depending on the dosage form of Agent A. The content of the aqueous medium in Agent A is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more, from the perspective of ease of mixing with Agent B. From the perspective of ease of multi-color expression, it is preferably 98% by mass or less.

[0103] The content of the aqueous medium in Agent A may be the remainder of the component (A1), the component (A2), the antioxidant, and the pH adjuster.

[0104] [Other ingredients]

[0105] In addition to the above-mentioned components, Agent A may also contain components commonly used in hair dye compositions as appropriate, within a range that does not impair the purpose of the present invention. Examples of such components include surfactants, viscosity modifiers, silicones, aromatic alcohols, coloring components other than Component (A1), polymers, oils, antidandruff agents, vitamins, bactericides, anti-inflammatory agents, preservatives, chelating agents, moisturizers, pearlescent agents, ceramides, fragrances, and ultraviolet absorbers.

[0106] Agent A may contain coloring ingredients other than component (A1). However, according to the hair dyeing method of the present invention, Agent A may not substantially contain coloring ingredients other than component (A1). Furthermore, "substantially containing no coloring ingredients other than component (A1)" means that the content of coloring ingredients other than component (A1) in Agent A is preferably 1% by mass or less, more preferably 0.5% by mass or less, further preferably 0.2% by mass or less, and further more preferably 0% by mass.

[0107] In this specification, a coloring component means a colorant or a precursor thereof. Examples of coloring components other than component (A1) include colorants or precursors thereof other than component (A1) commonly used in hair dye compositions, such as oxidation dyes, direct dyes, and pigments other than component (A1).

[0108] From the perspective of suppressing hair damage, Agent A contains substantially no oxidizing agent. The term "Agent A contains substantially no oxidizing agent" means that the content of oxidizing agent in Agent A is preferably less than 0.1% by mass, more preferably less than 0.01% by mass, and even more preferably 0% by mass.

[0109] Examples of the oxidizing agent include peroxides such as hydrogen peroxide, urea peroxide, and melamine peroxide, with hydrogen peroxide being preferred. Furthermore, the oxidizing agent content refers to the content of the active ingredient of the oxidizing agent. For example, when a hydrogen peroxide solution is used as the oxidizing agent, the oxidizing agent content refers to the hydrogen peroxide content.

[0110] The dosage form of Agent A is not particularly limited and may be any form, such as liquid, foam, paste, cream, solid, or powder. From the perspective of ease of mixing with Agent B and application to hair by coating, dipping, or the like, Agent A is preferably in the form of a liquid, foam, cream, or cream.

[0111] The preparation method of agent A is not particularly limited. For example, it can be prepared by mixing component (A1), component (A2), an aqueous medium, and other components used as needed, and using a known stirring device or the like. Based on the viewpoint of avoiding the polymerization of component (A1), agent A is preferably prepared under an inert gas atmosphere such as nitrogen.

[0112] [pH value]

[0113] From the perspective of improving hair dyeing properties, the pH of Agent A is preferably 8.0 or higher, more preferably 9.0 or higher, even more preferably 9.5 or higher, and even more preferably 9.8 or higher. Furthermore, from the perspective of improving hair dyeing properties and suppressing hair damage, the pH is preferably 11.0 or lower, more preferably 10.8 or lower, and even more preferably 10.5 or lower.

[0114] The pH value is a value measured at 25° C., and can be specifically measured by the method described in the Examples.

[0115] (Dose B)

[0116] Agent B used in step (I) contains the following components (B1) and (B2):

[0117] (B1) oxidation dyes other than component (A1);

[0118] (B2) Alkaline agent.

[0119] [Component (B1): Oxidation dye other than component (A1)]

[0120] Agent B contains component (B1): an oxidation dye other than component (A1) as a coloring component.

[0121] As the oxidation dye used as the component (B1), compounds known as precursors and couplers may be mentioned.

[0122] Examples of the precursor include p-phenylenediamine, toluene-2,5-diamine, 2-chloro-p-phenylenediamine, N-methoxyethyl-p-phenylenediamine, N,N-bis(2-hydroxyethyl)-p-phenylenediamine, 2-(2-hydroxyethyl)-p-phenylenediamine, 2,6-dimethyl-p-phenylenediamine, 4,4'-diaminodiphenylamine, 1,3-bis(N-(2-hydroxyethyl)-N-(4-aminophenyl)amino)-2-propanol, PEG-3,3,2'-p-phenylenediamine, p-aminophenol, p-methylaminophenol, 3-methyl-4-aminophenol [=4-aminophenol],

[0065] 2-aminomethyl-4-aminophenol, 2-(2-hydroxyethylaminomethyl)-4-aminophenol, o-aminophenol, 2-amino-5-methylphenol, 2-amino-6-methylphenol, 2-amino-5-acetamidophenol, 3,4-diaminobenzoic acid, 5-aminosalicylic acid, 2,4,5,6-tetraaminopyrimidine, 2,5,6-triamino-4-pyrimidinol, 4,5-diamino-1-(4'-chlorobenzyl)pyrazole, 1-hydroxyethyl-4,5-diaminopyrazole, and one or more salts thereof.

[0123] The coupling agent may be, for example, a compound selected from the group consisting of m-phenylenediamine, 2,4-diaminophenoxyethanol, 2-amino-4-(2-hydroxyethylamino)anisole [= 2-amino-4-(β-hydroxyethyl)aminoanisole], 2,4-diamino-5-methylphenethyl ether, 2,4-diamino-5-(2-hydroxyethoxy)toluene, 2,4-dimethoxy-1,3-diaminobenzene, 2,6-bis(2-hydroxyethylamino)toluene, 2,4-dimethoxy-1,3-diaminobenzene, 2,6-bis(2-hydroxyethylamino)toluene, 2,4-diamino-5-methylphenethyl ether, 2,4-diamino-5-(2-hydroxyethoxy ...amino-5-methylphenethyl ether, 2,4-diamino-5-(2-hydroxyethoxy)toluene, 2,4-dimethoxy-1,3-diaminobenzene, 2,6-bis(2-hydroxyethylamino)toluene, 4-Diamino-5-fluorotoluene, 1,3-bis(2,4-diaminophenoxy)propane, m-aminophenol, 2-methyl-5-aminophenol [= 5-amino-o-cresol], 2-methyl-5-(2-hydroxyethylamino)phenol, 2,4-dichloro-3-aminophenol, 2-chloro-3-amino-6-methylphenol, 2-methyl-4-chloro-5-aminophenol, N-cyclopentyl-m-aminophenol, 2-methyl-4-methoxy-5-(2 -hydroxyethylamino)phenol, 2-methyl-4-fluoro-5-aminophenol, resorcinol, 2-methylresorcinol, 4-chlororesorcinol, 1-naphthol, 1,5-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 2-isopropyl-5-methylphenol, 4-hydroxyindole, 5-hydroxyindole, 6-hydroxyindole, 7-hydroxyindole, 6-hydroxybenzomorpholine, 3,4-methylenedioxyphenol, 2-bromo-4,5-methylenedioxyphenol One or more of dioxyphenol, 3,4-methylenedioxyaniline, 1-(2-hydroxyethyl)amino-3,4-methylenedioxybenzene, 2,6-dihydroxy-3,4-dimethylpyridine, 2,6-dimethoxy-3,5-diaminopyridine, 2,3-diamino-6-methoxypyridine, 2-methylamino-3-amino-6-methoxypyridine, 2-amino-3-hydroxypyridine, 2,6-diaminopyridine, and salts thereof.

[0124] One or more of the above-mentioned oxidation dyes can be used as component (B1). Component (B1) may contain only a precursor or a precursor and a coupler together.

[0125] Component (B1) can be appropriately selected depending on the desired color. From the viewpoint of use in combination with component (A1), it is preferred that it contain one or more selected from p-aminophenol, toluene-2,5-diamine, 2,4,5,6-tetraaminopyrimidine, 2,5,6-triamino-4-pyrimidinol, 1-hydroxyethyl-4,5-diaminopyrazole, m-aminophenol, and salts thereof. It is more preferred that it contain one or more selected from p-aminophenol, toluene-2,5-diamine, 2,5,6-triamino-4-pyrimidinol, 1-hydroxyethyl-4,5-diaminopyrazole, and salts thereof. It is even more preferred that it contain p-aminophenol.

[0126] The content of component (B1) in agent B is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, further preferably 0.05% by mass or more, further more preferably 0.10% by mass or more, further more preferably 0.15% by mass or more, from the viewpoint of improving hair dyeing properties and facilitating the expression of various colors. From the viewpoint of the solubility of component (B1) and the stability of the formulation, it is preferably 5.0% by mass or less, more preferably 3.0% by mass or less, further preferably 2.0% by mass or less.

[0127] [Ingredient (B2): Alkaline agent]

[0128] Component (B2) has the same function as the above-mentioned component (A2).

[0129] Component (B2) is not particularly limited as long as it is an alkali agent commonly used in hair dye compositions, and may be either an inorganic alkali agent or an organic alkali agent. Component (B2) is preferably ammonia or an organic alkali agent from the viewpoint of improving hair dyeing properties.

[0130] Preferred alkali agents as component (B2) include ammonia; alkanolamines such as monomethanolamine, dimethanolamine, trimethanolamine, monoethanolamine, diethanolamine, triethanolamine, trishydroxymethylaminomethane, and 2-amino-2-methyl-1-propanol; alkylamines such as methylamine, dimethylamine, ethylamine, diethylamine, N-methylethylamine, propylamine, and butylamine; and aralkylamines such as benzylamine. One or more of these can be used. From the perspective of water solubility, the number of carbon atoms in the alkanolamine, alkylamine, or aralkylamine is preferably 1 to 10, more preferably 1 to 8.

[0131] Among the above, from the perspective of improving hair dyeing properties and facilitating the expression of various colors, component (B2) preferably comprises one or more selected from ammonia, alkanolamines, alkylamines, and aralkylamines, more preferably comprises one or more selected from ammonia and alkanolamines, and even more preferably comprises alkanolamines. Among the alkanolamines, from the perspective of improving hair dyeing properties and facilitating the expression of various colors, component (B2) preferably comprises one or more selected from monoethanolamine, trishydroxymethylaminomethane, and 2-amino-2-methyl-1-propanol, more preferably comprises one or more selected from monoethanolamine and 2-amino-2-methyl-1-propanol, and even more preferably comprises monoethanolamine.

[0132] From the viewpoint of improving hair dyeing properties and facilitating the expression of various colors, the content of the alkanolamine in component (B2) is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, and is 100% by mass or less.

[0133] Component (A2) and component (B2) may be the same or different types of alkali agents, but are preferably the same type of alkali agents from the viewpoint of miscibility between Agents A and B and ease of pH adjustment.

[0134] That is, component (A2) and component (B2) preferably contain one or more selected from ammonia, alkanolamine, alkylamine, and aralkylamine, more preferably contain one or more selected from ammonia and alkanolamine, and even more preferably contain alkanolamine.

[0135] The content of component (B2) in agent B is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.5% by mass or more, even more preferably 1.0% by mass or more, even more preferably 2.0% by mass or more, from the viewpoint of improving hair dyeing properties. From the viewpoint of suppressing hair damage, it is preferably 10% by mass or less, more preferably 7.5% by mass or less, even more preferably 5.0% by mass or less.

[0136] [Ingredient (B3): Antioxidant]

[0137] From the viewpoint of suppressing the oxidative polymerization of the component (B1) outside the hair, the agent B preferably further contains an antioxidant as the component (B3).

[0138] Examples of the antioxidant include sulfurous acid, pyrosulfurous acid, hydrogen sulfite, sulfur dioxide, L-ascorbic acid, thioglycolic acid, L-cysteine, N-acetyl-L-cysteine, and salts and derivatives thereof. Examples of the salt include alkali metals such as sodium and potassium.

[0139] Among the above, from the viewpoint of the inhibitory effect of oxidative polymerization of component (B1) outside the hair, the antioxidant is preferably one or more selected from sulfites, pyrosulfites, bisulfites, sulfur dioxide, L-ascorbic acid, and L-ascorbic acid salts, more preferably one or more selected from sodium sulfite and sodium L-ascorbate, and even more preferably sodium sulfite.

[0140] When Agent B contains an antioxidant (B3), from the viewpoint of enhancing the effect of inhibiting the oxidative polymerization of Component (B1) outside the hair, the content of Component (B3) in Agent B is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more, even more preferably 0.2% by mass or more, and is preferably 10% by mass or less, more preferably 5.0% 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, even more preferably 0.5% by mass or less.

[0141] When Agent B contains an antioxidant (B3), the mass ratio of component (B3) to component (B1) in Agent B [(B3) / (B1)] is preferably 0.05 or more, more preferably 0.1 or more, and even more preferably 0.2 or more, from the viewpoint of the inhibitory effect of oxidative polymerization of component (B1) outside the hair. Furthermore, from the viewpoint of improving hair dyeing properties, it is preferably 10 or less, more preferably 5.0 or less, even more preferably 3.0 or less, and even more preferably 2.5 or less.

[0142] [pH adjuster]

[0143] From the viewpoint of adjusting the pH value to the desired range described below, promoting the polymerization reaction of the component (B1) in the hair, and improving the hair dyeing properties, the agent B preferably further contains a pH adjuster.

[0144] Since Agent B contains an alkaline agent as component (B2), a protonating agent is preferably used as the pH adjuster for Agent B. The protonating agent may be either a monobasic acid or a polybasic acid, and may be either an organic acid (having 1 to 8 carbon atoms, excluding ascorbic acid) or an inorganic acid.

[0145] Examples of the protonating agent include one or more selected from hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid, and citric acid. From the viewpoint of adjusting the pH of Agent B to the following range, one or more selected from phosphoric acid and citric acid are preferred.

[0146] The pH adjusters used in Agent A and Agent B may be of the same type or different types. However, from the perspective of miscibility between Agent A and Agent B and ease of pH adjustment, they are preferably of the same type.

[0147] When Agent B contains a pH adjuster, the content of the pH adjuster in Agent B is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.2% by mass or more, and is preferably 5.0% by mass or less, more preferably 4.0% by mass or less, even more preferably 3.5% by mass or less, even more preferably 2.5% by mass or less, and even more preferably 1.5% by mass or less, from the viewpoint of adjusting the pH value of Agent B to the following range.

[0148] [Aqueous medium]

[0149] Agent B typically further contains an aqueous medium. Examples of the aqueous medium include water; lower alcohols such as ethanol and isopropyl alcohol; and low-molecular-weight diols and triols having 6 or fewer carbon atoms, such as 1,3-butylene glycol, glycerol, ethylene glycol, and propylene glycol. From the perspective of solubility of component (B1) and component (B2), affinity for hair, and prevention of hair damage, the aqueous medium is preferably one or more selected from water and ethanol, and more preferably water.

[0150] The content of the aqueous medium in Agent B is generally in the range of 1 to 99% by mass and can be appropriately selected depending on the dosage form of Agent B. The content of the aqueous medium in Agent B is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more, from the perspective of ease of mixing with Agent A. From the perspective of ease of multi-color expression, it is preferably 98% by mass or less.

[0151] The content of the aqueous medium in Agent B may be the remainder of the component (B1), the component (B2), the antioxidant, and the pH adjuster.

[0152] [Other ingredients]

[0153] In addition to the above-mentioned components, Agent B may also contain components commonly used in hair dye compositions as appropriate, within the scope not impairing the purpose of the present invention. Examples of such components include surfactants, viscosity modifiers, silicones, aromatic alcohols, coloring components other than Component (B1), polymers, oils, antidandruff agents, vitamins, bactericides, anti-inflammatory agents, preservatives, chelating agents, moisturizers, pearlescent agents, ceramides, fragrances, and ultraviolet absorbers.

[0154] Agent B may contain coloring ingredients other than component (B1). However, according to the hair dyeing method of the present invention, Agent B may not substantially contain coloring ingredients other than component (B1). In addition, "substantially containing no coloring ingredients other than component (B1)" means that the content of coloring ingredients other than component (B1) in Agent B is preferably 1% by mass or less, more preferably 0.5% by mass or less, further preferably 0.2% by mass or less, and further more preferably 0% by mass.

[0155] Examples of coloring components other than component (B1) include coloring components other than component (B1) in colorants or precursors thereof generally used in hair dye compositions, such as component (A1), direct dyes, and pigments.

[0156] From the perspective of suppressing hair damage, Agent B contains substantially no oxidizing agent. This means that the content of oxidizing agent in Agent B is preferably less than 0.1% by mass, more preferably less than 0.01% by mass, and even more preferably 0% by mass.

[0157] Examples of the oxidizing agent include peroxides such as hydrogen peroxide, urea peroxide, and melamine peroxide, with hydrogen peroxide being preferred. Furthermore, the oxidizing agent content refers to the content of the active ingredient of the oxidizing agent. For example, when a hydrogen peroxide solution is used as the oxidizing agent, the oxidizing agent content refers to the hydrogen peroxide content.

[0158] The dosage form of Agent B is not particularly limited and may be any form, such as liquid, foam, paste, cream, solid, or powder. From the perspective of ease of mixing with Agent A and application to hair by coating, dipping, etc., Agent B is preferably in the form of a liquid, cream, or cream, and more preferably a liquid.

[0159] The dosage forms of Agent A and Agent B may be the same or different, but are preferably the same dosage form from the viewpoint of ease of mixing.

[0160] The preparation method of Agent B is not particularly limited. For example, it can be prepared by blending Component (B1), Component (B2), an aqueous medium, and other components as needed, and mixing them using a known stirring apparatus or the like.

[0161] [pH value]

[0162] From the perspective of improving hair dyeing properties, the pH of Agent B is preferably 8.0 or higher, more preferably 9.0 or higher, even more preferably 9.5 or higher, and even more preferably 9.8 or higher. Furthermore, from the perspective of improving hair dyeing properties and suppressing hair damage, the pH is preferably 11.0 or lower, more preferably 10.8 or lower, and even more preferably 10.5 or lower.

[0163] The pH value is a value measured at 25° C., and can be specifically measured by the method described in the Examples.

[0164] In step (I), the above-mentioned agents A and B are mixed before use to prepare a hair dye composition. In this specification, "mixing agents A and B before use" means mixing agents A and B before applying the hair dye composition to the hair. In the present invention, this means mixing immediately before step (II).

[0165] Mixing of Agent A and Agent B can be carried out in the air at room temperature by conventional methods. This mixing can be carried out, for example, by preparing Agent A and Agent B in separate containers, removing each of the agents from the prepared containers, and mixing them in new containers.

[0166] From the perspective of improving hair dyeing properties and facilitating the expression of various colors, the mixing ratio of Agent A and Agent B in step (I) is such that the molar ratio of component (A1) to component (B1) [(A1) / (B1)] is 10 / 90 to 70 / 30, preferably 20 / 80 to 70 / 30, more preferably 30 / 70 to 70 / 30, further preferably 30 / 70 to 60 / 40, and further preferably 40 / 60 to 60 / 40. If the molar ratio [(A1) / (B1)] is 10 / 90 or more, hair dyeing properties are improved, and if it is 70 / 30 or less, the expression of various colors becomes easier.

[0167] In step (I), the formulation of the hair dye composition obtained by mixing Agents A and B is appropriately set according to the formulations of Agents A and B. The formulation of the hair dye composition is preferably liquid, paste, or cream, more preferably liquid.

[0168] In step (I), from the viewpoint of improving hair dyeing properties, the pH value of the hair dye composition obtained by mixing Agent A and Agent B at 25°C is preferably 8.0 or higher, more preferably 9.0 or higher, even more preferably 9.5 or higher, and even more preferably 9.8 or higher. Furthermore, from the viewpoint of improving hair dyeing properties and suppressing hair damage, the pH value is preferably 11.0 or lower, more preferably 10.8 or lower, and even more preferably 10.5 or lower.

[0169] The above pH value is a value measured at 25° C. and can be measured by the same method as above.

[0170] <Step (II)>

[0171] In step (II), the hair dye composition prepared in step (I) is applied to hair.

[0172] The method for applying the hair dye composition to hair may be any method that allows the hair dye composition to come into contact with the hair. Examples thereof include a method of applying the composition to dry or wet hair, and a method of immersing dry or wet hair in the composition. Of these, a method of applying the hair dye composition to dry hair is preferred.

[0173] From the viewpoint of the balance between hair dyeing properties and economic efficiency, the amount of the hair dye composition applied to the hair is preferably in a bath ratio (dry mass of hair:mass of hair dye composition) of 1:0.2 to 1:20, more preferably 1:0.5 to 1:10, even more preferably 1:0.5 to 1:5, and even more preferably 1:0.8 to 1:3.

[0174] The hair to be applied is preferably the head, and any hair may be applied to at least a portion of the head.

[0175] In step (II), when the hair dye composition is applied to the hair, the application time is preferably 10 seconds or longer, more preferably 20 seconds or longer, from the viewpoint of improving hair dyeing properties, and is preferably 10 minutes or shorter, more preferably 5 minutes or shorter, from the viewpoint of reducing the burden on the hair dyer.

[0176] In step (II), it is preferred that the hair dye composition be applied to the hair and then left to stand for a period of time. The period of time during this period is preferably 1 minute or longer, more preferably 3 minutes or longer, from the perspective of improving hair dyeing properties, and is preferably 30 minutes or shorter, more preferably 20 minutes or shorter, from the perspective of reducing the burden on the person being treated.

[0177] The temperature during step (II) is not particularly limited, but is preferably 40°C or lower, more preferably 35°C or lower, from the viewpoint of handleability of the hair dye composition. Furthermore, from the viewpoint of improving hair dyeing properties, it is preferably 25°C or higher, more preferably 30°C or higher.

[0178] <Rinsing process>

[0179] The method of the present invention preferably includes a step of rinsing the hair dye composition applied to the hair after step (II) (hereinafter also referred to as the "rinsing step"). The rinsing step is performed, for example, by rinsing the hair dye composition applied to the hair with water. The temperature of the water is not particularly limited, but warm water of 35 to 45°C is preferably used. The duration of the warm water rinse is not particularly limited, but is preferably 15 to 45 seconds.

[0180] <Drying Process>

[0181] The method of the present invention preferably includes a step of drying the hair (hereinafter also referred to as the "drying step") after the rinsing step. The hair drying step is a step of reducing the moisture content of the hair. For example, it includes performing one or more drying treatments selected from towel drying, hair drying (with cold air or hot air), and air drying to actively reduce the moisture content of the hair. Preferably, a combination of two or more of these drying treatments is performed. Of these, a combination of towel drying and a hair dryer with cold air is more preferred, and towel drying followed by a hair dryer with cold air is even more preferred.

[0182] From the viewpoint of suppressing hair damage, the method of the present invention does not include the step of applying an oxidizing agent to the hair.

[0183] In the present specification, “not including the step of applying an oxidizing agent to the hair” means not including the step of applying a solution or composition containing 0.01% by mass or more of an oxidizing agent to the hair.

[0184] The aforementioned "composition containing 0.01% by mass or more of an oxidizing agent" also includes a hair dye composition. Therefore, the hair dye composition applied to hair and Agent A and Agent B constituting the hair dye composition also contain substantially no oxidizing agent.

[0185] Furthermore, "applying an oxidizing agent to hair" means, for example, contacting a solution or composition containing 0.01% by mass or more of an oxidizing agent with the hair before, during, or after dyeing by coating, immersion, or the like. Examples of the oxidizing agent include peroxides such as hydrogen peroxide, urea peroxide, and melamine peroxide, with hydrogen peroxide being preferred.

[0186] Thus, hair damage is suppressed in hair treated by the method of the present invention. Hair damage can be evaluated by the goodness of finger combing of hair after hair dyeing (tactile evaluation). Specifically, it can be evaluated by the method described in the Examples.

[0187] In addition to the above-mentioned touch evaluation, hair damage can also be evaluated by the amount of cysteic acid produced (for example, see Reference 1 (Teruo Horiuchi, Fragrance Journal, December 2019, Vol. 18, No. 12, pp. 69-86)).

[0188] Evaluation of cysteic acid production can be performed, for example, as follows. First, a 10 cm long hair bundle is subjected to each hair dyeing treatment, and 5 hairs are collected. The ATR method is used by PerkinElmer's Spectrum 3 at a frequency resolution of 4 cm. -1 The ATR-IR spectrum of the central part of the collected hair was measured under the conditions of 4 times of cumulative number. At this time, the S=O symmetric stretching vibration of the sulfonic acid group (-SO3H) of cysteic acid generated by the hair dyeing process appeared at 1040 cm -1 Nearby. With amide (1650cm -1 After normalizing the entire spectrum so that the peak height of 1033 cm -1 and 1049cm -1 The data points are connected with a straight line, the area value of the portion above the straight line is calculated, and the value obtained by multiplying the area value by 100 is used as the cysteic acid signal intensity, and the value is used as the cysteic acid production amount. The hair dyeing treatment of the present invention can be performed while fully suppressing the production of cysteic acid.

[0189] Furthermore, according to the method of the present invention, various color expressions can be easily performed as described above.

[0190] The multi-colored nature of the color expression can be evaluated by the difference in chroma C value (ΔC) between the case where hair is dyed with Agent A and Agent B alone and the case where Agent A and Agent B are mixed and dyed with the above-mentioned hair dye composition. That is, the difference ΔC in chroma C value between the hair dyed with Agent A alone and the hair dyed with the above-mentioned hair dye composition can be calculated. A , and the difference ΔC between the chroma C value of hair treated with only agent B and the chroma C value of hair treated with the above-mentioned hair dye composition B Specifically, the evaluation can be performed by the method described in the examples. In this case, the values ​​of these differences are preferably within a specific range. For example, preferably ΔC A is 1.0 to 12.0 and ΔC B 1.7 to 12.0, more preferably ΔC A is 2.5 to 11.0 and ΔC B 2.0 to 10.0, more preferably ΔC A is 5.0 to 9.0 and ΔC B It is 4.0 to 7.5.

[0191] [Hair dyeing set]

[0192] Furthermore, the present invention provides a hair dyeing kit comprising an agent A and an agent B, and excluding a preparation containing an oxidizing agent.

[0193] Agent A contains the following ingredients (A1) and (A2):

[0194] (A1) a compound represented by the following general formula (1) or a salt thereof,

[0195]

[0196] [Wherein, the dotted line indicates the presence or absence of a π bond; R 1 represents a hydroxyl group or an acetoxy group, R 2 represents a hydrogen atom, or -COOR (R is a hydrogen atom, a methyl group or an ethyl group); R 3 represents a hydrogen atom, an acetyl group, a methyl group or an ethyl group;]

[0197] (A2) alkali agent;

[0198] Agent B contains the following ingredients (B1) and (B2):

[0199] (B1) oxidation dyes other than the above-mentioned component (A1);

[0200] (B2) Alkaline agent.

[0201] Agent A and Agent B and their preferred embodiments are the same as those described above, and neither Agent A nor Agent B contains an oxidizing agent. The oxidizing agent and its specific examples are the same as those described above.

[0202] The hair dyeing set of the present invention only needs to include the aforementioned Agent A and Agent B. For example, a two-component set may be provided, wherein Agent A and Agent B are sealed in separate containers. The shape of the container is not particularly limited and can be appropriately selected depending on the dosage form. Examples include bottles, tubes, dispensers, and sprayers.

[0203] The hair dyeing set of the present invention may further comprise a preparation other than the above-mentioned agent A and agent B. However, it is preferred that the preparation does not substantially contain an oxidizing agent.

[0204] The hair dyeing set may further include a comb, a brush, etc. for applying the hair dye composition obtained by mixing Agent A and Agent B to the hair, etc., as needed.

[0205] The hair dyeing set of the present invention can preferably be used according to the method described in the above-mentioned hair dyeing method.

[0206] Hereinafter, the present invention further discloses the following details regarding the above-mentioned embodiment.

[0207] <1>

[0208] A method for dyeing hair, comprising the steps (I) and (II) in this order, and not comprising the step of applying an oxidizing agent to the hair.

[0209] Step (I): A step of preparing a hair dye composition by mixing Agent A and Agent B before use.

[0210] The above-mentioned agent A contains the following ingredients (A1) and (A2):

[0211] (A1) a compound represented by the following general formula (1) or a salt thereof,

[0212]

[0213] [Wherein, the dotted line indicates the presence or absence of a π bond; R 1 represents a hydroxyl group or an acetoxy group; R 2 represents a hydrogen atom, or -COOR (R is a hydrogen atom, a methyl group or an ethyl group); R 3 represents a hydrogen atom, an acetyl group, a methyl group or an ethyl group;]

[0214] (A2) alkali agent;

[0215] The above-mentioned agent B contains the following ingredients (B1) and (B2):

[0216] (B1) oxidation dyes other than the above-mentioned component (A1);

[0217] (B2) alkali agent;

[0218] Step (II): a step of applying the hair dye composition to hair, and

[0219] The mixing ratio of the agent A and the agent B in the step (I) is such that the molar ratio of the component (A1) to the component (B1) [(A1) / (B1)] is 10 / 90 to 70 / 30.

[0220] <2>

[0221] like <1> The dyeing method, wherein the above-mentioned component (A1) is selected from 5,6-dihydroxyindole, 5,6-dihydroxyindole-2-carboxylic acid, 5,6-dihydroxyindole-2-carboxylic acid methyl ester, 5,6-dihydroxyindole-2-carboxylic acid ethyl ester, N-methyl-5,6-dihydroxyindole, N-methyl-5,6-dihydroxyindole-2-carboxylic acid, N-ethyl-5,6-dihydroxyindole, N-ethyl-5,6-dihydroxyindole-2-carboxylic acid, N-acetyl-5,6-dihydroxyindole, N-acetyl-5,6-dihydroxyindole-2-carboxylic acid, 5-acetoxy-6-hydroxyindole, 5-acetoxy-6-hydroxyindole-2-carboxylic acid, 5,6-dihydroxyindoline, 5,6-dihydroxyindoline-2-carboxylic acid, 5,6-dihydroxyindoline-2-carboxylic acid methyl ester, 5,6-dihydroxyindoline-2-carboxylic acid ethyl ester, N-methyl-5,6-dihydroxyindoline, N-methyl-5,6-dihydroxyindoline-2-carboxylic acid, N-ethyl-5,6-dihydroxyindoline, N-ethyl-5,6-dihydroxyindoline-2-carboxylic acid, N-acetyl-5,6-dihydroxyindoline, N-acetyl-5,6-dihydroxyindoline-2-carboxylic acid, 5-acetoxy-6-hydroxyindoline, and 5-acetoxy-6-hydroxyindoline-2-carboxylic acid; and one or more of the hydrochloride, hydrobromide, sulfate, phosphate, acetate, propionate, lactate, and citrate of these compounds, preferably the hydrobromide of these compounds.

[0222] <3>

[0223] like <1> or <2> The dyeing method of claim 1, wherein the component (A1) is preferably one or more selected from 5,6-dihydroxyindole, 5,6-dihydroxyindole-2-carboxylic acid, 5,6-dihydroxyindoline, 5,6-dihydroxyindole-2-carboxylic acid, and salts thereof, more preferably one or more selected from 5,6-dihydroxyindole, 5,6-dihydroxyindole-2-carboxylic acid, and 5,6-dihydroxyindoleline hydrobromide, further preferably one or more selected from 5,6-dihydroxyindole and 5,6-dihydroxyindole-2-carboxylic acid, further more preferably contains 5,6-dihydroxyindole, and further more preferably contains 5,6-dihydroxyindole and 5,6-dihydroxyindole-2-carboxylic acid.

[0224] <4>

[0225] like <1> to <3> The dyeing method according to any one of the preceding claims, wherein R in the general formula (1) of the component (A1) is 2 When -COOH is present, the salt of the compound represented by the general formula (1) is its carboxylate (R 2 -COO - X + (X + is a cation)).

[0226] <5>

[0227] like <1> to <4> The dyeing method according to any one of the preceding claims, wherein when the component (A1) contains 5,6-dihydroxyindole and 5,6-dihydroxyindole-2-carboxylic acid, the molar ratio of the 5,6-dihydroxyindole to the 5,6-dihydroxyindole-2-carboxylic acid is preferably in the range of 50:50 to 99:1, more preferably in the range of 80:20 to 99:1, and even more preferably in the range of 85:15 to 95:5.

[0228] <6>

[0229] like <1> to <5> The dyeing method according to any one of the preceding claims, wherein the content of the component (A1) is preferably 0.02% by mass or more, more preferably 0.05% by mass or more, and still more preferably 0.1% by mass or more, and is preferably 5.0% by mass or less, more preferably 3.0% by mass or less, still more preferably 2.0% by mass or less, still more preferably 1% by mass or less, still more preferably 0.8% by mass or less, and still more preferably 0.5% by mass or less.

[0230] <7>

[0231] like <1> to <6> The dyeing method according to any one of the preceding claims, wherein the component (B1) comprises at least one selected from a precursor and a coupler.

[0232] <8>

[0233] like <7> The dyeing method, wherein the precursor comprises a member selected from the group consisting of p-phenylenediamine, toluene-2,5-diamine, 2-chloro-p-phenylenediamine, N-methoxyethyl-p-phenylenediamine, N,N-bis(2-hydroxyethyl)-p-phenylenediamine, 2-(2-hydroxyethyl)-p-phenylenediamine, 2,6-dimethyl-p-phenylenediamine, 4,4'-diaminodiphenylamine, 1,3-bis(N-(2-hydroxyethyl)-N-(4-aminophenyl)amino)-2-propanol, PEG-3,3,2'-p-phenylenediamine, p-aminophenol, p-methylaminophenol, 3-methyl-4-aminophenol. =4-amino-m-cresol], 2-aminomethyl-4-aminophenol, 2-(2-hydroxyethylaminomethyl)-4-aminophenol, o-aminophenol, 2-amino-5-methylphenol, 2-amino-6-methylphenol, 2-amino-5-acetamidophenol, 3,4-diaminobenzoic acid, 5-aminosalicylic acid, 2,4,5,6-tetraaminopyrimidine, 2,5,6-triamino-4-pyrimidinol, 4,5-diamino-1-(4'-chlorobenzyl)pyrazole, 1-hydroxyethyl-4,5-diaminopyrazole, and one or more salts thereof.

[0234] <9>

[0235] like <7> or <8> The dyeing method, wherein the coupling agent is selected from m-phenylenediamine, 2,4-diaminophenoxyethanol, 2-amino-4-(2-hydroxyethylamino)anisole [= 2-amino-4-(β-hydroxyethyl)aminoanisole], 2,4-diamino-5-methylphenethyl ether, 2,4-diamino-5-(2-hydroxyethoxy)toluene, 2,4-dimethoxy-1,3-diaminobenzene, 2,6-bis(2-hydroxyethylamino)toluene , 2,4-diamino-5-fluorotoluene, 1,3-bis(2,4-diaminophenoxy)propane, m-aminophenol, 2-methyl-5-aminophenol [= 5-amino-o-cresol], 2-methyl-5-(2-hydroxyethylamino)phenol, 2,4-dichloro-3-aminophenol, 2-chloro-3-amino-6-methylphenol, 2-methyl-4-chloro-5-aminophenol, N-cyclopentyl-m-aminophenol, 2-methyl-4-methoxy-5 -(2-Hydroxyethylamino)phenol, 2-methyl-4-fluoro-5-aminophenol, resorcinol, 2-methylresorcinol, 4-chlororesorcinol, 1-naphthol, 1,5-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 2-isopropyl-5-methylphenol, 4-hydroxyindole, 5-hydroxyindole, 6-hydroxyindole, 7-hydroxyindole, 6-hydroxybenzomorpholine, 3,4-methylenedioxyphenol, 2-bromo-4,5 -methylenedioxyphenol, 3,4-methylenedioxyaniline, 1-(2-hydroxyethyl)amino-3,4-methylenedioxybenzene, 2,6-dihydroxy-3,4-dimethylpyridine, 2,6-dimethoxy-3,5-diaminopyridine, 2,3-diamino-6-methoxypyridine, 2-methylamino-3-amino-6-methoxypyridine, 2-amino-3-hydroxypyridine, 2,6-diaminopyridine, and one or more salts thereof.

[0236] <10>

[0237] like <1> to <9> The dyeing method according to any one of the preceding claims, wherein the component (B1) preferably contains one or more selected from p-aminophenol, toluene-2,5-diamine, 2,4,5,6-tetraaminopyrimidine, 2,5,6-triamino-4-pyrimidinol, 1-hydroxyethyl-4,5-diaminopyrazole, m-aminophenol, and salts thereof, and more preferably contains p-aminophenol.

[0238] <11>

[0239] like <1> to <10> The dyeing method according to any one of the preceding claims, wherein the content of the component (B1) in the agent B is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, further preferably 0.05% by mass or more, further more preferably 0.10% by mass or more, further more preferably 0.15% by mass or more, and is preferably 5.0% by mass or less, more preferably 3.0% by mass or less, further preferably 2.0% by mass or less.

[0240] <12>

[0241] like <1> to <11> The dyeing method according to any one of the preceding claims, wherein the component (A2) and / or the component (B2) is preferably ammonia or an organic alkaline agent, more preferably comprises at least one selected from ammonia, alkanolamines, alkylamines, and arylalkylamines, further preferably comprises at least one selected from ammonia and alkanolamines, and further more preferably comprises alkanolamines.

[0242] <13>

[0243] like <12> The dyeing method, wherein the number of carbon atoms of the alkanolamine, the alkylamine, or the aralkylamine is preferably 1 to 10, more preferably 1 to 8.

[0244] <14>

[0245] like <12> or <13> The dyeing method, wherein the component (A2) and / or the component (B2) preferably contains one or more selected from monoethanolamine, trishydroxymethylaminomethane and 2-amino-2-methyl-1-propanol, more preferably contains one or more selected from monoethanolamine and 2-amino-2-methyl-1-propanol, and further preferably contains monoethanolamine.

[0246] <15>

[0247] like <12> to <14> The dyeing method according to any one of the preceding claims, wherein the content of the alkanolamine in the component (A2) and / or the component (B2) is 70% by mass or more, more preferably 80% by mass or more, further preferably 90% by mass or more, and is 100% by mass or less.

[0248] <16>

[0249] like <1> to <15> The dyeing method according to any one of the preceding claims, wherein the content of the component (A2) in the agent A and / or the component (B2) in the agent B is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, further preferably 0.5% by mass or more, further more preferably 1.0% by mass or more, further more preferably 2.0% by mass or more, and is preferably 10% by mass or less, more preferably 7.5% by mass or less, further preferably 5.0% by mass or less.

[0250] <17>

[0251] like <1> to <16> The dyeing method according to any one of the preceding claims, wherein the component (A2) and the component (B2) are the same type of alkali agent.

[0252] <18>

[0253] like <1> to <17> The dyeing method according to any one of the preceding claims, wherein the agent A further contains an antioxidant as a component (A3).

[0254] <19>

[0255] like <18> A dyeing method, wherein the component (A3) contains at least one selected from sulfurous acid, pyrosulfite, hydrogen sulfite, sulfur dioxide, L-ascorbic acid, thioglycolic acid, L-cysteine, N-acetyl-L-cysteine ​​and salts thereof, and derivatives thereof, preferably contains at least one selected from sulfites, pyrosulfites, hydrogen sulfites, sulfur dioxide, L-ascorbic acid and L-ascorbic acid salts, more preferably one or more selected from sodium sulfite and sodium L-ascorbate, and even more preferably sodium sulfite.

[0256] <20>

[0257] like <18> or <19> A dyeing method, wherein the content of the above-mentioned component (A3) in the above-mentioned agent A is preferably 0.01 mass% or more, more preferably 0.05 mass% or more, further preferably 0.1 mass% or more, further more preferably 0.2 mass% or more, and is preferably 10 mass% or less, more preferably 5.0 mass% or less, further preferably 3.0 mass% or less, further more preferably 2.0 mass% or less, further more preferably 1.0 mass% or less, further more preferably 0.5 mass% or less.

[0258] <21>

[0259] like <18> to <20> The dyeing method according to any one of the preceding claims, wherein the component (A3) is contained, and the mass ratio of the component (A3) to the component (A1) in the agent A [(A3) / (A1)] is preferably 0.05 or more, more preferably 0.1 or more, further preferably 0.2 or more, further preferably 0.3 or more, further preferably 0.5 or more, further more preferably 0.8 or more, further more preferably 1.0 or more, further more preferably 1.2 or more, and preferably 10 or less, more preferably 5.0 or less, further preferably 3.0 or less, further more preferably 2.0 or less.

[0260] <22>

[0261] like <1> to <21> The dyeing method according to any one of the preceding claims, wherein the agent B further contains an antioxidant as a component (B3).

[0262] <23>

[0263] like <22> A dyeing method, wherein the component (B3) contains at least one selected from sulfurous acid, pyrosulfite, hydrogen sulfite, sulfur dioxide, L-ascorbic acid, thioglycolic acid, L-cysteine, N-acetyl-L-cysteine ​​and salts thereof, and derivatives thereof, preferably contains at least one selected from sulfites, pyrosulfites, hydrogen sulfites, sulfur dioxide, L-ascorbic acid and L-ascorbic acid salts, more preferably contains at least one selected from sodium sulfite and sodium L-ascorbate, and further preferably is sodium sulfite.

[0264] <24>

[0265] like <22> or <23> A dyeing method, wherein the content of the component (B3) in the agent B is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, further preferably 0.1% by mass or more, further more preferably 0.2% by mass or more, and is preferably 10% by mass or less, more preferably 5.0% by mass or less, further preferably 3.0% by mass or less, further more preferably 2.0% by mass or less, further more preferably 1.0% by mass or less, further more preferably 0.5% by mass or less.

[0266] <25>

[0267] like <22> to <24> The dyeing method according to any one of the preceding claims, wherein the component (B3) is contained, and the mass ratio of the component (B3) to the component (B1) in the agent B [(B3) / (B1)] is preferably 0.05 or more, more preferably 0.1 or more, and further preferably 0.2 or more, and is preferably 10 or less, more preferably 5.0 or less, further preferably 3.0 or less, and further more preferably 2.5 or less.

[0268] <26>

[0269] like <1> to <25> The dyeing method according to any one of the above, wherein the above-mentioned agent A and / or the above-mentioned agent B further contains a pH adjuster, and the above-mentioned pH adjuster is preferably one or more protonating agents selected from monobasic acids and polybasic acids, or one or more protonating agents selected from organic acids (having 1 to 8 carbon atoms, excluding ascorbic acid) and inorganic acids. As the protonating agent, it is more preferably one or more selected from hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid, and citric acid, and more preferably one or more selected from phosphoric acid and citric acid.

[0270] <27>

[0271] like <26> The dyeing method according to any one of the preceding claims, wherein the content of the pH adjuster is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and still more preferably 0.2% by mass or more, and is preferably 5.0% by mass or less, more preferably 4.0% by mass or less, still more preferably 3.5% by mass or less, still more preferably 2.5% by mass or less, and still more preferably 1.5% by mass or less.

[0272] <28>

[0273] like <26> or <27> The dyeing method, wherein the pH adjuster used in the above-mentioned agent A and the above-mentioned agent B is the same type of pH adjuster.

[0274] <29>

[0275] like <1> to <28> The dyeing method according to any one of the preceding claims, wherein the pH value of the above-mentioned agent A and / or the above-mentioned agent B is preferably 8.0 or higher, more preferably 9.0 or higher, further preferably 9.5 or higher, further more preferably 9.8 or higher, and is preferably 11.0 or lower, more preferably 10.8 or lower, further preferably 10.5 or lower.

[0276] <30>

[0277] like <1> to <29> The dyeing method according to any one of the preceding claims, wherein the agent A and / or the agent B further contains an aqueous medium, and the aqueous medium is preferably one or more selected from water, lower alcohols, and low molecular weight diols and triols having a carbon number of 6 or less, more preferably one or more selected from water and ethanol, and further preferably water.

[0278] <31>

[0279] like <30> A dyeing method, wherein the content of the aqueous medium in the above-mentioned agent A and / or the above-mentioned agent B is in the range of 1 to 99 mass%, preferably 50 mass% or more, more preferably 70 mass% or more, further preferably 80 mass% or more, and preferably 98 mass% or less.

[0280] <32>

[0281] like <1> to <31> The dyeing method according to any one of the preceding claims, wherein the agent A further contains at least one selected from the group consisting of a surfactant, a viscosity modifier, silicone, an aromatic alcohol, a coloring component other than the component (A1), a polymer, an oil, an antidandruff agent, a vitamin, a bactericide, an anti-inflammatory agent, a preservative, a chelating agent, a moisturizer, a pearlescent agent, a ceramide, a fragrance, and a UV absorber.

[0282] <33>

[0283] like <1> to <32> The dyeing method according to any one of the preceding claims, wherein the agent A does not substantially contain a coloring component other than the component (A1), and the content of the coloring component other than the component (A1) in the coloring component in the agent A is preferably 1% by mass or less, more preferably 0.5% by mass or less, further preferably 0.2% by mass or less, and further more preferably 0% by mass.

[0284] <34>

[0285] like <1> to <33> The dyeing method according to any one of the preceding claims, wherein the agent B further contains at least one selected from the group consisting of a surfactant, a viscosity modifier, silicone, an aromatic alcohol, a coloring component other than the component (B1), a polymer, an oil, an antidandruff agent, a vitamin, a bactericide, an anti-inflammatory agent, a preservative, a chelating agent, a moisturizer, a pearlescent agent, a ceramide, a fragrance, and a UV absorber.

[0286] <35>

[0287] like <1> to <34> The dyeing method according to any one of the above, wherein the agent B does not substantially contain a coloring component other than the component (B1), and the content of the coloring component other than the component (B1) in the coloring component in the agent B is preferably 1% by mass or less, more preferably 0.5% by mass or less, further preferably 0.2% by mass or less, and further more preferably 0% by mass.

[0288] <36>

[0289] like <1> to <35> The dyeing method according to any one of the above, wherein the above-mentioned agent A and / or the above-mentioned agent B does not substantially contain an oxidizing agent, and the content of the above-mentioned oxidizing agent in the above-mentioned agent A and / or the above-mentioned agent B is preferably less than 0.1% by mass, more preferably less than 0.01% by mass, and further preferably 0% by mass.

[0290] <37>

[0291] like <36> The dyeing method, wherein the oxidizing agent is a peroxide, preferably hydrogen peroxide.

[0292] <38>

[0293] like <1> to <37> The dyeing method according to any one of the preceding claims, wherein the formulation of the above-mentioned agent A and / or the above-mentioned agent B is in liquid, foam, paste, cream, solid, or powder form, preferably in liquid, paste or cream form, and more preferably in liquid form.

[0294] <39>

[0295] like <38> The dyeing method, wherein the dosage forms of the above-mentioned agent A and the above-mentioned agent B are the same dosage form.

[0296] <40>

[0297] like <1> to <39> The dyeing method according to any one of the preceding claims, wherein the agent A is prepared by blending the component (A1), the component (A2), an aqueous medium, and other components as needed, preferably under an inert gas atmosphere.

[0298] <41>

[0299] like <1> to <40> The dyeing method according to any one of the preceding claims, wherein the agent B is prepared by blending the component (B1), the component (B2), an aqueous medium, and other components as needed.

[0300] <42>

[0301] like <1> to <41> The dyeing method according to any one of the preceding claims, wherein in the step (I), the agent A and the agent B are mixed immediately before the step (II) of applying the hair dye composition to the hair.

[0302] <43>

[0303] like <1> to <42> The dyeing method according to any one of the preceding claims, wherein the mixing before use in the step (I) is performed by taking out the agent A and the agent B from containers for preparing the respective agents and mixing them in new containers.

[0304] <44>

[0305] like <1> to <43> The hair dyeing method according to any one of the above, wherein the hair dye composition obtained by the above step (I) is preferably in the form of a liquid, a paste or a cream, and more preferably in the form of a liquid.

[0306] <45>

[0307] like <1> to <44> The hair dyeing method according to any one of the preceding claims, wherein the pH of the hair dye composition at 25°C is preferably 8.0 or higher, more preferably 9.0 or higher, further preferably 9.5 or higher, further more preferably 9.8 or higher, and is preferably 11.0 or lower, more preferably 10.8 or lower, further preferably 10.5 or lower.

[0308] <46>

[0309] like <1> to <45> The dyeing method according to any one of claims 1 to 4, wherein in the step (II), the method of applying the hair dye composition to the hair is a method of bringing the hair dye composition into contact with the hair, preferably a method of applying the hair dye composition to dry or wet hair, or a method of immersing dry or wet hair in the hair dye composition.

[0310] <47>

[0311] like <1> to <46> The dyeing method according to any one of claims 1 to 4, wherein in the step (II), the amount of the hair dye composition applied to the hair is preferably in a bath ratio (dry mass of hair:mass of hair dye composition) of 1:0.2 to 1:20, more preferably 1:0.5 to 1:10, even more preferably 1:0.5 to 1:5, and even more preferably 1:0.8 to 1:3.

[0312] <48>

[0313] like <1> to <47> The dyeing method according to any one of claims 1 to 4, wherein in the step (II), when the hair dye composition is applied to the hair, the application time is preferably 10 seconds or longer, more preferably 20 seconds or longer, and preferably 10 minutes or shorter, more preferably 5 minutes or shorter.

[0314] <49>

[0315] like <1> to <48> The dyeing method according to any one of the preceding claims, wherein in the step (II), after applying the hair dye composition to the hair, the step (II) is followed by a step of leaving the hair to stand, wherein the leaving time is preferably 1 minute or longer, more preferably 3 minutes or longer, and preferably 30 minutes or shorter, more preferably 20 minutes or shorter.

[0316] <50>

[0317] like <1> to <49> The dyeing method according to any one of the preceding claims, wherein the temperature during step (II) is preferably 40°C or lower, more preferably 35°C or lower, and preferably 25°C or higher, more preferably 30°C or higher.

[0318] <51>

[0319] like <1> to <50> The dyeing method according to any one of the preceding claims, further comprising the step of rinsing the hair dye composition applied to the hair after the step (II), wherein the rinsing step is preferably performed by rinsing the hair dye composition with water, and more preferably the temperature of the water is 35 to 45°C.

[0320] <52>

[0321] like <51> A dyeing method, wherein, after the step of rinsing the hair, there is a drying step of drying the hair, preferably one or more drying treatments selected from the group consisting of towel drying, hair dryer drying (with cold air or hot air), and air drying, and more preferably a combination of two or more drying treatments.

[0322] <53>

[0323] like <1> to <52> The dyeing method according to any one of the preceding claims, which does not include the step of applying an oxidizing agent to the hair, and preferably does not include the step of applying a solution or composition containing 0.01% by mass or more of the oxidizing agent to the hair.

[0324] <54>

[0325] like <1> to <53> The dyeing method according to any one of the preceding claims, wherein the difference ΔC between the chroma C value of hair dyed with the hair dyeing agent A alone and the chroma C value of hair dyed with the hair dye composition is A , and the difference ΔC between the chroma C value of hair treated with the hair dyeing agent B alone and the chroma C value of hair treated with the hair dyeing agent composition B Preferably ΔC A is 1.0 to 12.0 and ΔC B 1.7 to 12.0, more preferably ΔC A is 2.5 to 11.0 and ΔC B 2.0 to 10.0, more preferably ΔC A is 5.0 to 9.0 and ΔC B It is 4.0 to 7.5.

[0326] <55>

[0327] A hair dyeing kit comprising an agent A and an agent B, and excluding a preparation containing an oxidizing agent.

[0328] Agent A contains the following ingredients (A1) and (A2):

[0329] (A1) a compound represented by the following general formula (1) or a salt thereof,

[0330]

[0331] [wherein, the dashed line indicates the presence or absence of a π bond; R 1 represents a hydroxyl group or an acetoxy group; R 2 represents a hydrogen atom, or -COOR (R is a hydrogen atom, a methyl group or an ethyl group); R 3 represents a hydrogen atom, an acetyl group, a methyl group or an ethyl group;]

[0332] (A2) An alkaline agent;

[0333] The agent B contains the following components (B1) and component (B2):

[0334] (B1) An oxidation dye other than the above component (A1);

[0335] (B2) An alkaline agent.

[0336] <56>

[0337] A hair dyeing set as in <55>, wherein the above agent A has a constitution as described in any one of <2> to <6>, <12> to <21>, <26> to <33> and <36> to <39>.

[0338] <57>

[0339] A hair dyeing set as in <55> or <56>, wherein the above agent B has a constitution as described in any one of <7> to <17>, <22> to <31> and <34> to <39>.

[0340] <58>

[0341] A hair dyeing set as in any one of <55> to <57>, which has a two-component type obtained by separately enclosing the above agent A and the above agent B in different containers.

[0342] [Examples]

[0343] Hereinafter, examples of the present invention will be described, but the present invention is not limited to the scope of the examples. Furthermore, in this example, various measurements and evaluations are carried out by the following methods.

[0344] <pH value measurement>

[0345] Using a pH meter (F-51, manufactured by Horiba, Ltd.), the pH values of the agent A, the agent B, and the hair dye composition at 25°C are measured.

[0346] <Touch evaluation>

[0347] Dyed hair bundles obtained by dyeing according to the methods of Example 1 and Comparative Example 1 were rinsed with water and dried. Five panelists evaluated the goodness of finger combing during rinsing. The number of panelists who rated "good finger combing" was used to determine a score based on the following criteria.

[0348] A: The number of panelists who rated "Finger combing is good" was 4 or more.

[0349] B: 2 to 3 panelists rated the product as "good for finger combing"

[0350] C: The number of panelists who rated "good finger combing" was one or less

[0351] <Chroma and Difference ΔC after Processing>

[0352] A goat hair bundle (manufactured by Beaulax Co., Ltd., 10 cm in length, 1.0 g in weight) was used instead of a hair bundle and dyed according to the method of each example. In each example, the hair dyeing process was performed under the same conditions except that only Agent A or only Agent B was used.

[0353] The chromaticity (a) of each goat hair bundle after the dyeing treatment was measured at 6 locations on one hair bundle using a colorimeter ("CR-400" manufactured by Konica Minolta Co., Ltd.). * , b * ), calculate the chroma C by the following formula * Here, a * 、b * Means by CIE1976 L * a * b * a specified by the color system * 、b * .

[0354] C * =(a *2 +b *2 ) 1 / 2

[0355] <Difference ΔC>

[0356] Next, the difference ΔC in chroma after the treatment in this example compared to the treatment using only agent A was calculated using the following formula: A .

[0357] ΔC A =C * -C A *

[0358] (Where, C * is the chroma of each case, C A * This is the chroma obtained by treating with Agent A alone, and is the value of Comparative Example 2.

[0359] Furthermore, the difference ΔC in chroma after treatment in this example compared to treatment using only agent B was calculated using the following formula: B .

[0360] ΔC B =C * -C B *

[0361] (Where, C * is the chroma of each case, C B * The chroma obtained by treating with Agent B alone is: in Examples 1, 5 to 10, and Comparative Examples 7 to 8, it is the value of Comparative Example 3; in Example 2, it is the value of Comparative Example 4; in Example 3, it is the value of Comparative Example 5; and in Example 4, it is the value of Comparative Example 6.

[0362] By making ΔC A and ΔC B Respectively fall within the above numerical range, such as ΔC A is 1.0 to 12.0 and ΔC B A value of 1.7 to 12.0 means that the hair dyeing property is good, and that the color change is large compared to the treatment with only Agent A or only Agent B, and a variety of color expressions can be achieved.

[0363] <Color difference ΔE before and after treatment>

[0364] A goat hair bundle (manufactured by Beaulax Co., Ltd., length 10 cm, mass 1.0 g) was used and the hair dyeing treatment was performed by the method of each example to dye the goat hair bundle.

[0365] The color of the goat hair bundle before and after the hair dyeing treatment was measured at 6 locations per hair bundle using a colorimeter ("CR-400" manufactured by Konica Minolta Co., Ltd.).

[0366] L0 * 、a0 * 、b0 * : Color of goat hair bundle before hair dyeing (average value of 6 measurements)

[0367] L1 * 、a1 * 、b1 *: Color of goat hair bundle after hair dyeing (average value of 6 measurements)

[0368] Here, L * 、a * 、b * Means by CIE1976 L * a * b * L specified by the color system * 、a * 、b * .

[0369] Furthermore, the color difference ΔE was calculated according to the following formula, and the cases where ΔE was 15 or more were evaluated as A, and the cases where ΔE was less than 15 were evaluated as C. The results are shown in the table. A larger ΔE value means a higher degree of dyeing.

[0370] ΔE={(ΔL * ) 2 +(Δa * ) 2 +(Δb * ) 2} 1 / 2

[0371] Furthermore, ΔL * :L1 * -L0 * , Δa * :a1 * -a0 * , Δb * :b1 * -b0 * .

[0372] Example 1 (Dyeing and Evaluation of Hair)

[0373] <Preparation of Hair Bundles for Evaluation>

[0374] An untreated hair tress (human black hair, manufactured by Beaulax Co., Ltd., 30 cm in length, 10 g in weight) was washed twice with plain shampoo having the following composition, dried with hot air using a hair dryer for 30 minutes, and then left to stand at a temperature of 25°C and a relative humidity of 65% for at least one day and night to prepare the hair tress for the above-mentioned tactile evaluation.

[0375] Furthermore, an untreated goat hair bundle (manufactured by Beaulax Co., Ltd., length 10 cm, mass 1.0 g) was treated in the same manner to prepare a goat hair bundle for the above-mentioned chroma evaluation and color difference evaluation.

[0376]

[0377] <Preparation of Agent A and Agent B>

[0378] Under a nitrogen atmosphere, 5,6 - dihydroxyindole as component (A1) and sodium sulfite as an antioxidant were mixed in a 3 mass% - monoethanolamine aqueous solution in amounts shown in Table 1 and dissolved. Further, 75% phosphoric acid as a pH adjuster was added to adjust the pH to 10.2 to prepare Agent A.

[0379] And, under the atmosphere, p - aminophenol as component (B1) and sodium sulfite as an antioxidant were mixed in a 3 mass% - monoethanolamine aqueous solution in amounts shown in Table 1 and dissolved. Further, 75% phosphoric acid as a pH adjuster was added to adjust the pH to 10.2 to prepare Agent B.

[0380] In the following description, the mixing amounts shown in the table are mass% of the active ingredient amounts except for phosphoric acid.

[0381] And, the prepared Agent A was stored under a nitrogen atmosphere and aliquoted for use as needed.

[0382] The above Agent A and Agent B were mixed at a molar ratio [(A1) / (B1)] of 50 / 50 to prepare a hair dye composition (Step (I)). Then, under the atmosphere, the adjusted hair dye composition was rapidly applied to the above - mentioned hair bundles for evaluation at a bath ratio [dry mass of hair bundles: mass of hair dye composition] of 1:1 (Step (II)). In this state, it was left in the atmosphere for 10 minutes for hair dyeing treatment.

[0383] After 10 minutes, the hair bundles were rinsed with flowing warm water (about 40°C) for 30 seconds, and then washed with the above - mentioned ordinary shampoo. The washed hair bundles were dried with a towel, and then dried by blowing cold air with a hair dryer for 30 minutes. Using the dried hair bundles, tactile evaluation was performed by the above - mentioned method, and the results are shown in Table 1. Also, chroma evaluation after treatment and color difference evaluation before and after treatment were performed, and the results are shown in Table 2.

[0384] Comparative Example 1

[0385] Agent A, Agent B, and a 5.7 mass% - hydrogen peroxide solution, i.e., Agent C, were mixed in the proportions shown in Table 1 to prepare a hair dye composition containing an oxidizing agent. Except for using this composition for hair dyeing treatment, hair dyeing treatment and tactile evaluation were performed in the same manner as in Example 1. The results are shown in Table 1.

[0386] [Table 1]

[0387]

[0388] As shown in Table 1, the hair dyeing method of Comparative Example 1, which includes a step of applying an oxidizing agent to the hair, causes damage to the hair after the dyeing process, which is believed to result in a reduced feel of the treated hair. In contrast, the hair dyeing method of Example 1 exhibits significantly less hair damage than that of Comparative Example 1, which includes a step of applying an oxidizing agent. Consequently, the feel of the hair after the dyeing process is favorable, and the saturation and degree of dyeing are also high.

[0389] Examples 2 to 10, Comparative Examples 2 to 8

[0390] Hair dyeing was performed in the same manner as in Example 1 except that the formulations of Agents A and B and their mixing ratios were changed as shown in Tables 2 to 3. The chroma after treatment and the color difference before and after treatment were evaluated. The results are shown in Tables 2 to 3.

[0391] Comparative Examples 2 to 6

[0392] Agents A and B were prepared separately, each with the composition shown in Table 2, and mixed at a mass ratio of 1:1 to prepare a hair dye composition. Using this composition, hair dyeing was performed in the same manner as in Example 1. The chroma after treatment and the color difference before and after treatment were evaluated. The results are shown in Table 2.

[0393] In addition, since the hair dyeing treatments of Examples 2 to 10 and Comparative Examples 2 to 8 did not include a step of applying an oxidizing agent to the hair bundle, similarly to Example 1, damage to the hair bundle was considered sufficiently low and the evaluation of touch was omitted.

[0394]

[0395]

[0396] The following substances were used as the component (A1) described in the table.

[0397] (A1) 5,6-dihydroxyindole and 5,6-dihydroxyindole-2-carboxylic acid mixture: A mixture produced by the method described in Japanese Patent No. 5570161 was used. The molar ratio of 5,6-dihydroxyindole to 5,6-dihydroxyindole-2-carboxylic acid was 90:10. (A1) was prepared as a 1% by mass solution of HO / ethanol = 4 / 1 (wt / wt) and incorporated into Agent A.

[0398] As can be seen from Tables 2 and 3, the method of this embodiment provides good hair dyeing properties and can easily produce a variety of colors.

[0399] [Industrial Applicability]

[0400] According to the present invention, there is provided a hair dyeing method using a melanin precursor, which causes less hair damage due to dyeing, has excellent hair dyeing properties, and can easily achieve a variety of color expressions.

Claims

1. A method for dyeing hair, wherein: The hair dyeing method comprises the steps (I) and (II) in sequence and does not comprise the step of applying an oxidizing agent to the hair. Step (I): A step of preparing a hair dye composition by mixing Agent A and Agent B before use. The agent A contains the following ingredients (A1) and (A2): (A1) a compound represented by the following general formula (1) or a salt thereof, Wherein, the dotted line indicates the presence or absence of a π bond; R 1 represents a hydroxyl group or an acetoxy group; R 2 represents a hydrogen atom, or -COOR, wherein R is a hydrogen atom, a methyl group or an ethyl group; R 3 represents a hydrogen atom, an acetyl group, a methyl group or an ethyl group; (A2) alkali agent; The B agent contains the following ingredients (B1) and (B2): (B1) oxidation dyes other than the component (A1); (B2) alkali agent; Step (II): a step of applying the hair dye composition to hair, and The mixing ratio of the agent A and the agent B in the step (I) is such that the molar ratio (A1) / (B1) of the component (A1) to the component (B1) is 10 / 90 to 70 / 30.

2. The dyeing method according to claim 1, wherein The mixing ratio of the agent A and the agent B in the step (I) is such that the molar ratio (A1) / (B1) of the component (A1) to the component (B1) is 40 / 60 to 60 / 40.

3. The dyeing method according to claim 1 or 2, wherein The component (A2) or the component (B2) contains one or more selected from ammonia, alkanolamines, alkylamines, and aralkylamines.

4. The dyeing method according to any one of claims 1 to 3, wherein The component (A2) or the component (B2) contains one or more selected from the group consisting of monoethanolamine, trishydroxymethylaminomethane, and 2-amino-2-methyl-1-propanol.

5. The dyeing method according to any one of claims 1 to 4, wherein The content of the component (A2) in the agent A or the content of the component (B2) in the agent B is 0.01% by mass or more and 10% by mass or less.

6. The dyeing method according to any one of claims 1 to 5, wherein The agent A further contains an antioxidant as a component (A3).

7. The dyeing method according to any one of claims 1 to 6, wherein The hair dye composition has a pH value of 8.0 or higher and 11.0 or lower at 25°C.

8. The dyeing method according to any one of claims 1 to 7, wherein The mixing before use in the step (I) is performed by taking out the agent A and the agent B from the containers in which the agents were prepared, and mixing them in new containers.

9. A hair dyeing kit, wherein: The hair dyeing kit comprises an agent A and an agent B, and does not include a preparation containing an oxidizing agent. Agent A contains the following ingredients (A1) and (A2): (A1) a compound represented by the following general formula (1) or a salt thereof, Wherein, the dotted line indicates the presence or absence of a π bond; R 1 represents a hydroxyl group or an acetoxy group; R 2 represents a hydrogen atom, or -COOR, wherein R is a hydrogen atom, a methyl group or an ethyl group; R 3 represents a hydrogen atom, an acetyl group, a methyl group or an ethyl group; (A2) alkali agent; Agent B contains the following ingredients (B1) and (B2): (B1) an oxidation dye other than the component (A1); and (B2) an alkali agent.

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