Keratin fiber processing method

Abstract

To provide a keratin fiber treatment method capable of dyeing the hair in gray with little yellowness and improving finger combability in dyeing the hair with a composition containing a melanin precursor.SOLUTION: Provided is a keratin fiber treatment method comprising the following steps (i) and (ii) in this order: step (i), which is a step of applying a composition (1) containing (A) a compound represented by the general formula (1) or a salt thereof and (B) alkaline agent and having a pH of 8.0 or more and 12.0 or less to keratin fibers; and step (ii), which is a step of applying a composition (2) containing (C) a cationic surfactant and (D) a higher alcohol and having a pH of 3.5 or more and less than 8.0 to keratin fibers.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for treating keratin fibers. [Background Art]

[0002] Conventionally, air-oxidation type hair dyes using 5,6-dihydroxyindole, 5,6-dihydroxyindoline, which are melanin precursors, or derivatives thereof as hair dyes for gray hair dyeing are known. Since these melanin precursors do not use an oxidizing agent, they cause less damage to keratin fibers when used in hair dyes, and are highly convenient as dyes for hair dyes. For example, Patent Documents 1 to 4 disclose a composition containing the above melanin precursor, and a method for dyeing keratin fibers using the same. On the other hand, proposals have been made to incorporate a melanin precursor into a composition for keratin fibers such as shampoo that everyone uses in daily hair washing, so that high hair dyeing performance against gray hair can be exhibited easily and in a short period of time (see, for example, Patent Document 5). [Prior Art Literature] [Patent Literature]

[0003] [Patent Document 1] Japanese Unexamined Patent Publication No. 62-238878 [Patent Document 2] Japanese Unexamined Patent Publication No. 2-218606 [Patent Document 3] Japanese Unexamined Patent Publication No. 5-058860 [Patent Document 4] Japanese Unexamined Patent Publication No. 2018-052833 [Patent Document 5] Japanese Unexamined Patent Publication No. 2019-094326 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] Hair dyes containing melanin precursors have a slightly slower dyeing effect compared to regular oxidative hair dyes, and are characterized by the gradual dyeing of keratin fibers with repeated use. However, it has been found that when using a composition containing a melanin precursor, such as the shampoo composition shown in the example of Patent Document 5, the color of the dyed keratin fibers may become yellowish compared to the intended color (natural gray to black). The inventors investigated various compositions used before and after using the said composition and found that when other acidic compositions such as conditioners, rinses, or treatments, particularly other compositions with a pH of less than 4.9 at 25°C, are used after using the said composition, the color of the dyed keratin fibers gradually becomes yellowish, and the keratin fibers do not easily dye to the original color that is expressed when the melanin precursor is oxidized.

[0005] Patent documents 1, 2, 3, and 4 describe dyeing hair using a composition containing a melanin precursor and other compositions, but they do not address the above-mentioned problem. Furthermore, they do not describe solving the above problem by specifying the composition and physical properties of conditioning agents or treatment agents used after applying the melanin precursor to keratin fibers. The object of the present invention is to provide a keratin fiber treatment method that involves sequentially applying a composition containing a melanin precursor to keratin fibers, and then applying a composition that provides a conditioning or treatment effect to keratin fibers to keratin fibers, wherein even when these steps are repeated, a decrease in dyeability is suppressed, the fibers can be dyed to their original color which is expressed when the less yellowish melanin precursor is oxidized, and the fibers can be made to feel smooth to the touch. [Means for solving the problem]

[0006] The present inventors have found that the above problem can be solved by applying a first composition (composition (1)) containing a predetermined melanin precursor and an alkaline agent and having a predetermined pH, and a second composition (composition (2)) containing a cationic surfactant and a higher alcohol and having a predetermined pH, in this order to keratin fibers. In other words, the present invention relates to the following [1]~[2]. [1] A method for treating keratin fibers, comprising the following steps (i) and (ii) in order. Step (i): A step of applying a composition (1) containing the following components (A) and (B) and having a pH of 8.0 or higher and 12.0 or lower to keratin fibers. (A) Compounds represented by general formula (1) or salts thereof [ka] [In equation (1), the dashed line indicates the presence or absence of a π bond, R 1 R represents a hydroxyl group or an acetoxy group. 2 R represents a hydrogen atom or a -COOR group (where R is a hydrogen atom, a methyl group, or an ethyl group), 3 [This represents a hydrogen atom, an acetyl group, a methyl group, or an ethyl group.] (B) Alkaline agent Step (ii): A step of applying a composition (2) containing the following components (C) and (D) and having a pH of 3.5 or higher and less than 8.0 to keratin fibers. (C) Cationic surfactant (D) Higher alcohol [2] A keratin fiber composition kit comprising: composition (1) containing the following components (A) and (B) and having a pH of 8.0 or higher and 12.0 or lower; and composition (2) containing the following components (C) and (D) and having a pH of 3.5 or higher and less than 8.0. (A) Compounds represented by general formula (1) or salts thereof [ka] [In equation (1), the dashed line indicates the presence or absence of a π bond, R 1 R represents a hydroxyl group or an acetoxy group. 2represents a hydrogen atom or -COOR (R represents 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.] (B) Alkaline agent (C) Cationic surfactant (D) Higher alcohol Effects of the Invention

[0007] According to the present invention, there is provided a keratin fiber treatment method which sequentially comprises a step of applying a composition containing a melanin precursor to keratin fibers such as hair, and a step of applying a composition that imparts a conditioning effect or a treatment effect to the keratin fibers, wherein even if these steps are repeated, a reduction in dyeability is suppressed, the keratin fibers can be dyed in the original color of melanin precursor with less yellowing (natural gray to black), and the combability can be improved. Modes for Carrying Out the Invention

[0008] Embodiments of the keratin fiber treatment method and the composition kit for keratin fibers according to the present invention are described in detail below. In the present specification, the term "A to B" regarding the description of numerical values means "not less than A and not more than B" (when A < B) or "not more than A and not less than B" (when A > B). In addition, in the present invention, a combination of preferred embodiments is a more preferred embodiment.

[0009] [Keratin fiber treatment method] In the present invention, keratin fibers refer to mammalian body hair, specifically including hair, eyebrows, eyelashes, beards and the like. Among these, hair is preferred as the keratin fiber. In the present invention, the term "hair" mainly means head hair, and also includes black hair, white hair, or bleached hair. The composition for keratin fibers in the present invention refers to a composition used for keratin fibers. In the following description, the dyeing effect of keratin fibers by component (A) may be simply referred to as "dyeability".

[0010] The method for treating keratin fibers of the present invention comprises the following step (i) and step (ii) in this order. Step (i): a step of applying composition (1) comprising the following components (A) and (B) and having a pH of 8.0 or more and 12.0 or less to keratin fibers (A) a compound represented by general formula (1) or a salt thereof

Chemical Formula

[0011] The present inventors have conducted various studies on the problem that when repeatedly applying a composition containing a melanin precursor to keratin fibers such as hair and then applying another composition such as a conditioner or treatment, dyeability decreases, and the gradually developing color tone becomes yellowish. As a result, the inventors found that the above problem can be solved by a method for treating keratin fibers comprising: a step of applying a first composition containing a predetermined melanin precursor and an alkaline agent and having a predetermined pH to keratin fibers; and after this step, a step of applying a second composition containing a cationic surfactant and a higher alcohol and having a predetermined pH to keratin fibers. The present invention provides a keratin fiber treatment method in which, even when a first composition containing a melanin precursor such as a detergent is applied to keratin fibers, and then a second composition having a specific pH such as a conditioner or treatment is repeatedly applied, the decrease in dyeability is suppressed, the fibers can be dyed to their original color (natural gray to black) which is expressed when the melanin precursor with less yellowness is oxidized, and the fibers can be made to feel smooth to the touch.

[0012] The exact reasons for these effects are not clear, but one possible reason is as follows: By having steps (i) and (iii) in sequence, the cuticles of the keratin fibers open when the first composition, which has a specific pH, is applied. Then, when the second composition, which has a specific pH lower than that of the first composition, is applied, the keratin fibers contract, giving a smooth feel and coating, and ensuring good manageability. In addition, because the second composition has an appropriate pH, it is thought that the yellowing of the keratin fibers is suppressed as the keratin fibers are gradually dyed by repeating step (i), without hindering the dyeing properties of composition (1) applied to the keratin fibers in step (i).

[0013] (Step (i)) Step (i) is the step of applying composition (1), which contains the following components (A) and (B) and has a pH of 8.0 or higher and 12.0 or lower, to keratin fibers. (A) Compounds represented by general formula (1) or salts thereof [ka] [In equation (1), the dashed line indicates the presence or absence of a π bond, R 1 R represents a hydroxyl group or an acetoxy group. 2 R represents a hydrogen atom or a -COOR group (where R is a hydrogen atom, a methyl group, or an ethyl group), 3 [This represents a hydrogen atom, an acetyl group, a methyl group, or an ethyl group.] (B) Alkaline agent

[0014] In step (i), component (A), a melanin precursor, is supplied to the keratin fibers. After penetrating the keratin fibers, component (A) undergoes oxidative polymerization by oxygen in the atmosphere to form a melanin pigment (melanin polymer). Then, as step (i) is repeatedly performed, the keratin fibers are gradually dyed to the original color that emerges when the melanin precursor is oxidized. Furthermore, since step (ii), described later, is performed after step (i), a composition (2) with a predetermined pH is supplied to the keratin fibers, even if steps (i) and (ii) are repeated, a decrease in dyeability and a yellowish tint to the keratin fibers are suppressed.

[0015] In step (i), composition (1) may be applied to keratin fibers and then foamed up using hands or a brush. Alternatively, it may be foamed up beforehand by rubbing the palms or both hands together, or dispensed as foam from a foaming container, or a pre-foamed composition (1) may be applied to the keratin fibers. After application to the keratin fibers, it may be left for a certain period of time. From the viewpoint of balancing ease of use and dyeing properties, the total of the standing time and foaming time after application to the keratin fibers is preferably 10 seconds to 10 minutes, more preferably 20 seconds to 5 minutes, and even more preferably 30 seconds to 2 minutes. From the viewpoint of usability, the amount of composition (1) applied to the keratin fibers is preferably 0.01 to 2, and more preferably 0.05 to 1, when the mass of the keratin fibers is set to 1. Furthermore, prior to step (i), it is preferable to untangle the keratin fibers using a brush or other tool, from the viewpoint of making it easier to spread composition (1) onto the keratin fibers. Also, from the same viewpoint, it is preferable to wet the keratin fibers with water beforehand. The keratin fibers may be washed with a detergent such as shampoo before step (i). It is preferable to have a step of rinsing with water after washing.

[0016] Preferably, between step (i) and step (ii), there is a step of rinsing the keratin fibers with water. Furthermore, after the rinsing step, there may be a step of drying the keratin fibers as appropriate (hereinafter also simply referred to as the "drying step"). The drying step is a step of reducing the moisture content of the keratin fibers. The drying step includes, for example, a method of squeezing the keratin fibers to remove excess moisture. In addition, in order to actively reduce the moisture content of the keratin fibers, it is also possible to perform towel drying, dryer (cold or hot air) drying, air drying, and a combination of two or more of these drying treatments. From the viewpoint of ease of spreading composition (2) onto keratin fibers, it is preferable to keep the keratin fibers wet after the rinsing step and then proceed to step (ii). When the mass of keratin fibers to be used in step (ii) after step (i) is set to 1, the water content in the keratin fibers is preferably 0.1 or more, more preferably 0.2 or more, even more preferably 0.5 or more, and even more preferably 0.8 or more. There is no particular upper limit on the water content in the keratin fibers to be used in step (ii) after step (i), but it is usually 5 or less, and from the viewpoint of suppressing water dripping from the keratin fibers and improving workability, it is preferably 3 or less, more preferably 2 or less, and even more preferably 1.2 or less. The moisture content in keratin fibers can be measured by comparing the mass of the keratin fibers at each processing step with the mass of the keratin fibers that have been dried by applying hot air from a hairdryer for 30 minutes and then left to dry completely for at least 24 hours at a temperature of 25°C and a relative humidity of 65%.

[0017] More specifically, it is preferable to have the following steps (i-1), (i-2), and (i-3) between step (i) and step (ii). • Step (i-1): One of the following steps: applying composition (1) and letting it stand, foaming composition (1), or foaming composition (1) and then letting it stand. • Step (i-2): A step of rinsing the composition (1) on the keratin fibers with water. • Process (i-3): Process for drying keratin fibers In step (i-1), when whipping by hand, you may use your fingers, palms, or tools such as a brush to whip the mixture. In step (i-2), the water temperature during rinsing is preferably 0°C or higher, more preferably 5°C or higher, even more preferably 10°C or higher, and preferably 45°C or lower, more preferably 40°C or lower, from the viewpoint of efficiently washing away composition (1). In step (i-3), the keratin fibers may be completely dried (i.e., specifically, so that the amount of water in the keratin fibers is 0.01 or less when the mass of the keratin fibers is 1), or the keratin fibers may be squeezed to remove excess water and kept in a moist state. Furthermore, between steps (i) and (ii), step (i) may be optionally repeated, and the process may include a step of applying compositions other than composition (1) and composition (2) to keratin fibers.

[0018] <Composition (1)> The composition (1) used in step (i) is not particularly limited as long as it contains components (A) and (B). However, since the composition (1) of the present invention has the characteristic that keratin fibers are gradually dyed by repeated use, multiple uses may be necessary. For this reason, it is preferable to provide composition (1) as a keratin fiber composition such as a shampoo or other cleansing agent, rinse, conditioning agent, or treatment agent that can be easily dyed through daily hair care. Among these, composition (1) is more preferably a cleansing agent from the viewpoint of being easily dyed through daily hair care and obtaining good dyeing properties. There are no particular restrictions on the dosage form of composition (1), and it can be any dosage form, such as liquid, foam, paste, cream, solid, or powder. From the viewpoint of applicability to keratin fibers, it is preferable to use a liquid, paste, or cream.

[0019] The composition (1) used in step (i) contains components (A) and (B) described later, and has a pH of 8.0 or higher and 12.0 or lower. When the pH of composition (1) is 8.0 or higher, the polymerization reaction is promoted and the dyeability is improved. When the pH of composition (1) is 12.0 or lower, damage to keratin fibers can be suppressed while improving dyeability. The pH of composition (1) is preferably 8.5 or higher, more preferably 8.8 or higher, and even more preferably 9.0 or higher, from the viewpoint of further promoting the polymerization reaction and further improving dyeability. This is because component (A), which is a melanin precursor, reacts with oxygen in the air under basic conditions and is easily converted into melanin pigment. The pH is preferably 11.0 or lower, more preferably 10.5 or lower, and even more preferably 10.0 or lower, from the viewpoint of further improving dyeability and suppressing damage to keratin fibers. Specifically, the pH is preferably 8.5 to 11.0, more preferably 8.8 to 10.5, and even more preferably 9.0 to 10.0. The above pH values ​​were measured at 25°C and can be specifically measured by the method described in the examples.

[0020] <Ingredient (A)> The composition (1) used in step (i) contains component (A), which is a compound represented by the following general formula (1) or a salt thereof. Component (A) is a melanin precursor that polymerizes by air oxidation to be converted into a melanin pigment and acts as a dyeing agent for keratin fibers. [ka] [In equation (1), the dashed line indicates the presence or absence of a π bond, R 1 R represents a hydroxyl group or an acetoxy group. 2 R represents a hydrogen atom or a -COOR group (where R is a hydrogen atom, a methyl group, or an ethyl group), 3 [This represents a hydrogen atom, an acetyl group, a methyl group, or an ethyl group.] The melanin precursor of component (A) is an indole derivative or indoline derivative, which is a compound represented by general formula (1), or a salt thereof. In the present invention, one or more combinations thereof can be used. From the viewpoint of staining properties, component (A) is more preferably an indole derivative (i.e., a π bond exists in the dashed portion of general formula (1)). From the viewpoint of the availability and stainability of component (A), in general formula (1), R 1 is preferably a hydroxyl group, R 2 R is preferably a hydrogen atom or a -COOR (where R is a hydrogen atom, a methyl group, or an ethyl group), more preferably a hydrogen atom or a -COOH. 3 Preferably, it is a hydrogen atom.

[0021] The compounds represented by the general formula (1) include 5,6-dihydroxyindole, 5,6-dihydroxyindole-2-carboxylic acid, methyl 5,6-dihydroxyindole-2-carboxylic acid, ethyl 5,6-dihydroxyindole-2-carboxylic acid, 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, and 5-acetoxy-6-hydroxyindole-2 Examples include carboxylic acids, 5,6-dihydroxyindoline, 5,6-dihydroxyindoline-2-carboxylic acid, methyl 5,6-dihydroxyindoline-2-carboxylic acid, ethyl 5,6-dihydroxyindoline-2-carboxylic acid, 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, etc.

[0022] Examples of salts of the compound represented by the general formula (1) include hydrochloride, hydrobromide, sulfate, phosphate, acetate, propionate, lactate, and citrate of the compound, among which hydrobromide is preferred from the viewpoint of availability. Furthermore, in general formula (1), R 2 When is -COOH, the salt of the compound represented by general formula (1) is its carboxylate salt (R 2 ga-COO - X + (X + Na + , K + Alkali metal ions such as Ca + Mg +Examples include alkaline earth metal ions and cations such as ammonium ions.

[0023] From the viewpoint of dyeing keratin fibers to a natural color (gray to black), component (A) is preferably one or more selected from the group consisting of 5,6-dihydroxyindole, 5,6-dihydroxyindole-2-carboxylic acid, 5,6-dihydroxyindoline, 5,6-dihydroxyindoline-2-carboxylic acid, and salts thereof; more preferably one or more selected from the group consisting of 5,6-dihydroxyindole, 5,6-dihydroxyindole-2-carboxylic acid, and 5,6-dihydroxyindoline hydrobromide; even more preferably one or two selected from the group consisting of 5,6-dihydroxyindole and 5,6-dihydroxyindole-2-carboxylic acid; and even more preferably using 5,6-dihydroxyindole and 5,6-dihydroxyindole-2-carboxylic acid in combination. When 5,6-dihydroxyindole and 5,6-dihydroxyindole-2-carboxylic acid are used in combination, the molar ratio 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. When the molar ratio of 5,6-dihydroxyindole and 5,6-dihydroxyindole-2-carboxylic acid is within the above range, the finished color of the keratin fibers after dyeing will be closer to a natural color. The molar ratio of 5,6-dihydroxyindole to 5,6-dihydroxyindole-2-carboxylic acid can be quantified by reverse-phase HPLC.

[0024] The content of component (A) in composition (1) is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, from the viewpoint of improving dyeability. Furthermore, from the viewpoint of economic efficiency, it is preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 1.0% by mass or less, even more preferably 0.8% by mass or less, even more preferably 0.5% by mass or less, and even more preferably 0.3% by mass or less. Also, it is preferably 0.05% by mass to 5% by mass, more preferably 0.05% by mass to 3% by mass, even more preferably 0.1% by mass to 1.0% by mass, even more preferably 0.1% by mass to 0.8% by mass, even more preferably 0.1% by mass to 0.5% by mass, and even more preferably 0.1% by mass to 0.3% by mass.

[0025] <Ingredient (B)> The composition (1) used in step (i) contains component (B), which is an alkaline agent. The alkaline agent swells the keratin fibers, opening the cuticle and allowing dyeing components such as component (A) to penetrate into the keratin fibers. It also promotes the polymerization reaction of component (A), thereby improving dyeability. Any alkaline agent commonly used in hair dyes can be used without particular limitations as the alkaline agent. Examples of the alkaline agent include ammonia; alkanolamines such as mono-, di-, or triethanolamine; alkylamines such as methylamine, dimethylamine, ethylamine, diethylamine, N-methylethylamine, propylamine, and butylamine; aralkylamines such as benzylamine; and inorganic alkali compounds such as sodium hydroxide and potassium hydroxide. One or more of these can be used. From the viewpoint of water solubility, the number of carbon atoms in the alkanolamine, alkylamine, or aralkylamine is preferably 10 or less, more preferably 8 or less. In particular, from the viewpoint of staining properties, the alkaline agent is preferably one or more selected from the group consisting of ammonia, alkanolamines, alkylamines, aralkylamines, sodium hydroxide, and potassium hydroxide, more preferably containing one or more selected from the group consisting of ammonia and alkanolamines, even more preferably containing monoalkanolamines, and even more preferably containing monoethanolamines. In particular, component (B), which is an alkaline agent, is preferably one or more selected from the group consisting of ammonia and alkanolamines.

[0026] The content of component (B) in composition (1) is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.5% by mass or more, from the viewpoint of exhibiting high staining properties. Furthermore, from the viewpoint of suppressing irritation, it is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less. Also, it is preferably 0.01% by mass to 10% by mass, more preferably 0.1% by mass to 5% by mass, and even more preferably 0.5% by mass to 3% by mass. Furthermore, the ratio of the content of component (B) to the content of component (A) in composition (1) [component (B) / component (A)] is preferably 2 or more, more preferably 5 or more, even more preferably 8 or more, and also preferably 100 or less, more preferably 50 or less, and even more preferably 30 or less, from the viewpoint of exhibiting high dyeability and ensuring good manageability of the hair. Also preferably 2 to 100, more preferably 5 to 50, and even more preferably 8 to 30.

[0027] <Ingredient (E)> From the viewpoint of improving the stability of component (A), the composition (1) used in step (i) preferably further contains an antioxidant as component (E). Examples of antioxidants include sulfurous acid, pyrosulfite, bisulfite, sulfur dioxide, L-ascorbic acid, thioglycolic acid, L-cysteine, N-acetyl-L-cysteine ​​and their salts, as well as derivatives thereof. Alkali metals such as sodium and potassium can be preferably used as salts. Of these, sulfites, pyrosulfites, bisulfites, and sulfur dioxide are preferred as component (E) from the viewpoint of providing an effect (hereinafter also simply referred to as "yellowing suppression effect") that suppresses the yellowing of the dyed color when composition (2), or composition (2) and other acidic compositions, are used after applying composition (1). More specifically, preferred component (E) includes sodium sulfite, potassium sulfite, sodium hyposulfite, potassium hyposulfite, sulfur dioxide, potassium pyrosulfite, sodium pyrosulfite, etc. Of these, from the viewpoint of market availability, sulfites and pyrosulfites are preferred as component (E), and more specifically, one or more selected from the group consisting of sodium sulfite, potassium sulfite, sodium pyrosulfite, and potassium pyrosulfite are preferred. Furthermore, from the viewpoint of improving staining properties, component (E) is preferably L-ascorbic acid and its salts, or ascorbic acid glucoside, and more specifically, one or more selected from the group consisting of L-ascorbic acid, sodium L-ascorbate, and L-ascorbic acid glucoside. From the viewpoint of providing a yellowing-suppressing effect and improving staining properties, component (E) preferably contains one or more selected from the group consisting of L-ascorbic acid, sulfite, pyrosulfite, bisulfite or salts thereof, ascorbic acid glucoside, and sulfur dioxide. Component (E) may include (or be used in combination with) one or more first antioxidants selected from the group consisting of sulfites, pyrosulfites, bisulfites, and sulfur dioxide, and a second antioxidant different from the first antioxidant, from the viewpoint of providing a yellowing-suppressing effect and stabilizing component (A). In this case, it is preferable to include one or more selected from the group consisting of sulfites, pyrosulfites, bisulfites, and their salts, and one or more selected from the group consisting of L-ascorbic acid, sodium L-ascorbate, and L-ascorbic acid glucoside.

[0028] If composition (1) contains component (E), the content of component (E) in composition (1) is preferably 0.05% by mass or more, more preferably 0.1% by mass or more. Furthermore, it is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 2% by mass or less. Also, it is preferably 0.05% by mass to 10% by mass, more preferably 0.1% by mass to 5% by mass, and even more preferably 0.1% by mass to 2% by mass.

[0029] <Ingredients (F)> The composition (1) used in step (i) preferably further contains an anionic surfactant as component (F) from the viewpoint of improving foaming when using composition (1) and facilitating the even and uniform application of component (A), which is a dyeing component, to the keratin fibers. Component (F) provides a cleaning effect to the keratin fibers when composition (1) is a detergent. Furthermore, when a cationic polymer, which is an optional component described later, is used in combination, the combination of the cationic polymer and component (F) causes coacervation in a system in which composition (1) is diluted with water, allowing component (A) to be contained in the coacervate at a high concentration and adsorbed onto the surface of the keratin fibers, thereby achieving both a cleaning effect and high dyeability.

[0030] Examples of such anionic surfactants include alkylbenzene sulfonates, alkyl or alkenyl ether sulfates, alkyl or alkenyl sulfates, olefin sulfonates, alkanesulfonates, saturated or unsaturated fatty acid salts, alkyl or alkenyl ether carboxylates, α-sulfo fatty acid salts, N-acyl amino acid salts, phosphate mono or diesters, sulfosuccinate esters, etc., and one or more of these can be used. Examples of counterions for the anionic group of anionic surfactants include alkali metal ions such as sodium ions and potassium ions; alkaline earth metal ions such as calcium ions and magnesium ions; ammonium ions; and alkanolamines having 1 to 3 alkanol groups with 2 or 3 carbon atoms (e.g., monoethanolamine, diethanolamine, triethanolamine, triisopropanolamine, etc.). In particular, when composition (1) is a detergent, from the viewpoint of good foaming, ease of washing, and dyeability, one or more components selected from the group consisting of alkyl ether sulfates, N-acyl amino acid salts, and alkyl ether carboxylates are preferred as component (F), and one or more components selected from the group consisting of alkyl ether sulfates and alkyl ether carboxylates are more preferred. Examples of alkyl ether sulfates include polyoxyethylene alkyl ether sulfate, and examples of alkyl ether carboxylates include polyoxyethylene alkyl ether acetate. Examples of N-acyl amino acid salts include cocoyl glutamate.

[0031] If composition (1) contains component (F), the content of component (F) in composition (1) is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, preferably 40% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less, and even more preferably 17% by mass or less, from the viewpoint of good foaming and dyeing properties. Also, preferably 0.1% by mass to 40% by mass, more preferably 0.5% by mass to 30% by mass, even more preferably 1% by mass to 20% by mass, and even more preferably 1% by mass to 17% by mass. In particular, when composition (1) is a detergent, the content of component (F) in composition (1) is preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 8% by mass or more, from the viewpoint of good lathering, ease of washing, and dyeability. Furthermore, from the viewpoint of improving dyeability and suppressing damage to keratin fibers, the content of component (F) in composition (1) is preferably 40% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less, and even more preferably 17% by mass or less. Also, preferably 3% to 40% by mass, more preferably 5% to 30% by mass, even more preferably 8% to 20% by mass, and even more preferably 8% to 17% by mass.

[0032] <Other components in composition (1)> The composition (1) used in step (i) may, in addition to the above-mentioned components, appropriately contain components commonly used in keratin fiber compositions or hair dyes, to the extent that it does not impair the purpose of the present invention. Examples of such components include buffering agents, amphoteric surfactants, silicones, aromatic alcohols, dyes other than component (A), cationic polymers, polymers other than cationic polymers, nonionic surfactants, oils, anti-dandruff agents, vitamins, bactericides, anti-inflammatory agents, preservatives, chelating agents, humectants, pearlescent agents, ceramides, fragrances, UV absorbers, aqueous media, etc. Among these, it is preferable to contain one or more selected from the group consisting of buffering agents, amphoteric surfactants, cationic polymers, and aqueous media.

[0033] (buffering agent) The composition (1) used in step (i) preferably contains a buffer. Including a buffer makes it easier to maintain the optimal pH range for component (A) to exhibit high staining properties, even when composition (1) is diluted with water at the time of use. The buffering agent is not particularly limited as long as it has pH buffering properties, but since component (A), which is a melanin precursor, reacts with oxygen in the air under basic conditions and is easily converted into melanin pigment, a buffering agent that can adjust the pH of composition (1) to basic conditions is preferred. From the above viewpoint, the buffering agent is preferably a buffering agent containing one of the following basic components: sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, or glycine, sodium tetraborate, or ammonium chloride; or a buffering agent consisting of a combination of two or more basic components, such as sodium carbonate-sodium bicarbonate; a buffering agent containing a carbonate is more preferable; and a buffering agent containing sodium bicarbonate is even more preferable.

[0034] The buffering agent may further contain a protonating agent as a component of the buffering agent, from the viewpoint of improving pH buffering capacity. The protonating agent may be either a monobasic acid or a polybasic acid, and may be either an organic acid (with 1 to 8 carbon atoms, excluding ascorbic acid) or an inorganic acid. Examples of the protonating agent include one or more selected from the group consisting of hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid, and citric acid, with one or more selected from the group consisting of phosphoric acid and citric acid being more preferred.

[0035] From the viewpoint of improving dyeability, it is even more preferable that the components constituting the buffer consist of a combination of sodium bicarbonate and one or two selected from the group consisting of phosphoric acid and citric acid.

[0036] If composition (1) contains a buffering agent, the amount of buffering agent in composition (1) is not particularly limited as long as it is an amount that can adjust the pH of composition (1) to a desired range. However, from the viewpoint of improving the pH buffering capacity when composition (1) is diluted with water, it is preferably 0.1% by mass or more, more preferably 1.0% by mass or more, even more preferably 1.5% by mass or more, and particularly preferably 1.8% by mass or more. Furthermore, from the viewpoint of formulation stability, the amount of buffering agent in composition (1) 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 3.0% by mass or less, and particularly preferably 2.5% by mass or less. Also, it is preferably 0.1% by mass to 5.0% by mass, more preferably 1.0% by mass to 4.0% by mass, even more preferably 1.5% by mass to 3.5% by mass, even more preferably 1.8% by mass to 3.0% by mass, and particularly preferably 1.8% by mass to 2.5% by mass. Note that the buffering agent content refers to the total amount of active ingredients that make up the buffering agent.

[0037] (Amphoteric surfactant) The composition (1) used in step (i) may contain an amphoteric surfactant. Examples of amphoteric surfactants include betaine-based surfactants such as alkyldimethylaminoacetic acid betaine, fatty acid amidopropyl betaine, alkyl hydroxysulfobetaine, and N-acylaminoethyl-N-2-hydroxyethylaminocarboxylate salt; and sultaine-based surfactants such as lauryl hydroxysultaine. Among these, betaine-based surfactants are preferred from the viewpoint of their compatibility with keratin fibers and good foaming, and fatty acid amidopropyl betaine is more preferred. Fatty acid amidopropyl betaine is preferably one having an acyl group with 8 to 18 carbon atoms, and more preferably one to 16 carbon atoms, and is preferably one or more selected from the group consisting of lauric acid amidopropyl betaine, palm kernel oil fatty acid amidopropyl betaine, and coconut oil fatty acid amidopropyl betaine. Examples of N-acylaminoethyl-N-2-hydroxyethylaminocarboxylate salts include N-coconut oil fatty acid acyl-N'-carboxymethyl-N'-hydroxyethylethylenediamine [also known as sodium cocoamphoacetate or 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine], N-coconut oil fatty acid acyl-N'-carboxyethyl-N'-hydroxyethylethylenediamine [thorium cocoamphopropionate], and sodium N-lauroyl-N'-carboxymethyl-N'-hydroxyethylethylenediamine [sodium lauroamphoacetate].

[0038] If composition (1) contains an amphoteric surfactant, the content of the amphoteric surfactant in composition (1) is preferably 0.05% by mass or more, more preferably 0.10% by mass or more, even more preferably 0.15% by mass or more, even more preferably 0.50% by mass or more, even more preferably 1.0% by mass or more, preferably 15% by mass or less, more preferably 12% by mass or less, even more preferably 10% by mass or less, from the viewpoint of ease of compatibility with keratin fibers, good foaming, and improved feel during rinsing.

[0039] (cationic polymer) Composition (1) may contain a cationic polymer. The cationic polymer, in combination with component (F), induces coacervation, allowing component (A) to be incorporated into the coacervate at a high concentration and adsorbed onto the surface of the keratin fiber, thereby exhibiting high dyeability. In the present invention, a cationic polymer refers to a water-soluble polymer that has cationic groups and exhibits cationic properties as a whole. That is, the cationic polymer of the present invention includes not only cationic polymers that have only cationic groups and no anionic groups, but also amphoteric polymers that have both cationic and anionic groups and exhibit cationic properties as a whole. The above-mentioned anionic group refers to an anionic group, or a group that can be ionized to become an anionic group.

[0040] Examples of cationic polymers include cationized guar gum; cationized tara gum; cationized locust bean gum; cationized polyvinyl alcohol; cationized cellulose; cationized hydroxyalkyl cellulose such as cationized hydroxyethyl cellulose and cationized hydroxypropyl cellulose; cationic starch; quaternary dialkylaminoalkyl (meth)acrylate polymers such as vinylpyrrolidone / N,N-dimethylaminoethyl methacrylate diethyl sulfate copolymer and N,N-dimethylaminoethyl methacrylate diethyl sulfate / N,N-dimethylacrylamide / polyethylene glycol dimethacrylate copolymer; polydiallyldimethylammonium chloride, diallyldimethylammonium chloride / acrylic acid copolymer, diallyldimethylammonium chloride / acrylamide copolymer, diallyldimethyl Examples include diallyl quaternary ammonium salt polymers such as ammonium chloride / acrylic acid / acrylamide copolymers; vinylimidazolium trichloride / vinylpyrrolidone copolymers; vinylpyrrolidone / alkylamino(meth)acrylate copolymers; vinylpyrrolidone / alkylamino(meth)acrylate / vinylcaprolactam copolymers; vinylpyrrolidone / (meth)acrylamidopropyl chloride trimethylammonium copolymers; alkylacrylamide / (meth)acrylate / alkylaminoalkylacrylamide / polyethylene glycol (meth)acrylate copolymers; adipic acid / dimethylaminohydroxypropylethylenetriamine copolymers; and cationic polymers described in Japanese Patent Publication No. 53-139734 and Japanese Patent Publication No. 60-36407, and one or more of these can be used.

[0041] From the viewpoint of easily inducing coacervation and exhibiting high staining properties, the cationic polymer is preferably one or more selected from the group consisting of cationized guar gum, cationized tara gum, cationized locust bean gum, cationized polyvinyl alcohol, cationized hydroxyethyl cellulose, cationized hydroxypropyl cellulose, vinylpyrrolidone / N,N-dimethylaminoethyl methacrylate diethyl sulfate copolymer, N,N-dimethylaminoethyl methacrylate diethyl sulfate / N,N-dimethylacrylamide / polyethylene glycol dimethacrylate copolymer, polydiallyldimethylammonium chloride, diallyldimethylammonium chloride / acrylic acid copolymer, diallyldimethylammonium chloride / acrylamide copolymer, and diallyldimethylammonium chloride / acrylic acid / acrylamide polymer. More preferably, one or more selected from the group consisting of polypropyl cellulose, N,N-dimethylaminoethyl methacrylate diethyl sulfate / N,N-dimethylacrylamide / polyethylene glycol dimethacrylate copolymer, polydiallyldimethylammonium chloride, diallyldimethylammonium chloride / acrylic acid copolymer, diallyldimethylammonium chloride / acrylamide copolymer, and diallyldimethylammonium chloride / acrylic acid / acrylamide polymer are used. Even more preferably, one or more selected from the group consisting of cationized guar gum, cationized tara gum, cationized polyvinyl alcohol, cationized hydroxyethyl cellulose, cationized hydroxypropyl cellulose, N,N-dimethylaminoethyl methacrylate diethyl sulfate / N,N-dimethylacrylamide / polyethylene glycol dimethacrylate copolymer, diallyldimethylammonium chloride / acrylic acid copolymer, and diallyldimethylammonium chloride / acrylamide copolymer are used.

[0042] If composition (1) contains a cationic polymer, the content of the cationic polymer in composition (1) is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.2% by mass or more, and even more preferably 0.3% by mass or more, from the viewpoint of improving dyeability. Furthermore, from the viewpoint of improving stability and dyeability, it is preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 1.5% by mass or less, and even more preferably 1.0% by mass or less. Also, it is preferably 0.05% by mass to 5% by mass, more preferably 0.1% by mass to 3% by mass, even more preferably 0.2% by mass to 1.5% by mass, and even more preferably 0.3% by mass to 1.0% by mass.

[0043] (aqueous medium) Composition (1) typically contains an aqueous medium. Examples of aqueous mediums 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, glycerin, ethylene glycol, and propylene glycol, with water being preferred. If composition (1) contains an aqueous medium, the content of the aqueous medium in composition (1) can be appropriately selected depending on the dosage form of composition (1), but is usually in the range of 1 to 95% by mass. When water is used as the aqueous medium, in order to induce coacervation when composition (1) is diluted with water at the time of use, and to adsorb component (A) onto the surface of keratin fibers to exhibit high dyeability, the water content in composition (1) is preferably 40% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, and even more preferably 70% by mass or more, and also preferably 95% by mass or less, more preferably 90% by mass or less. Furthermore, it is preferably 40% by mass to 95% by mass, more preferably 50% by mass to 95% by mass, even more preferably 60% by mass to 90% by mass, and even more preferably 70% by mass to 90% by mass.

[0044] The method for producing composition (1) is not particularly limited. For example, it can be produced by blending components (A), (B), and other components as needed using the method described in the examples, and mixing them using a known stirring device or the like.

[0045] (Step (ii)) Step (ii) is performed after step (i) and involves applying composition (2), which contains the following components (C) and (D) and has a pH of 3.5 or higher and less than 8.0, to keratin fibers. (C) Cationic surfactant (D) Higher alcohol In step (ii), component (C), which is a cationic surfactant, and component (D), which is a higher alcohol, are supplied to the keratin fibers. The supply of components (C) and (D) provides a smooth feel and ease of separation after drying, ensuring good manageability. Furthermore, composition (2), which contains components (C) and (D) and has a predetermined pH, does not significantly affect the dyeability of composition (1) applied to the keratin fibers in step (i), and also suppresses the yellowing of the keratin fibers as step (i) is repeated and the keratin fibers are gradually dyed.

[0046] In step (ii), the amount of composition (2) applied to the keratin fibers is preferably 0.01 to 2, and more preferably 0.05 to 1, when the mass of the keratin fibers is 1, from the viewpoint of usability.

[0047] It is preferable that the following steps are taken after step (ii). [1] When composition (2) is used in a leave-off form • Step (ii-1): A step of washing off the composition (2) on the keratin fibers with water. After step (ii), step (ii-1) may be performed immediately, or step (ii-1) may be performed after letting it stand. If left to stand, the standing time is preferably 5 seconds or more, more preferably 30 seconds or more, even more preferably 1 minute or more, and also preferably 20 minutes or less, more preferably 15 minutes or less, and even more preferably 10 minutes or less. In step (ii-1), the temperature of the rinsing water is preferably 0°C or higher, more preferably 5°C or higher, even more preferably 10°C or higher, and preferably 45°C or lower, even more preferably 40°C or lower, from the viewpoint of efficiently rinsing off composition (2). Also preferably 0°C to 45°C, more preferably 5°C to 40°C, and even more preferably 10°C to 40°C. • Process (ii-2): Process for drying keratin fibers After performing step (ii-1), it is preferable to perform a drying step (step (ii-2)) of the keratin fibers. The keratin fibers may be dried completely (i.e., specifically, so that the amount of moisture in the keratin fibers is 0.01 or less when the mass of the keratin fibers is 1), or the keratin fibers may be squeezed to remove excess moisture and then subjected to step (i) again while remaining in a moist state. Furthermore, after step (ii-2), compositions other than composition (1) and composition (2) may optionally be applied to the keratin fibers.

[0048] [2] When composition (2) is used in a leave-on form • Process (ii-2): Process for drying keratin fibers It is preferable to perform step (ii) a process (ii-2) in which the keratin fibers are dried after applying composition (2) to the keratin fibers. In this case, it is more preferable to completely dry the keratin fibers from the viewpoint of fixing composition (2) onto the keratin fibers. Furthermore, after step (ii-2), compositions other than composition (1) and composition (2) may optionally be applied to the keratin fibers.

[0049] <Composition (2)> The composition (2) used in step (ii) contains component (C) and component (D) and has a predetermined pH, but is not particularly limited as long as it has a pH. However, it is preferably a composition for keratin fibers, and examples include cleansing agents such as shampoos, rinses, conditioning agents, treatments (including leave-in types), styling agents, hair growth agents, etc., which are used in daily hair care. Among these, from the viewpoint of maintaining the dyeability of the keratin fibers treated with composition (1) and ensuring good manageability, composition (2) is preferably a rinse, conditioning agent, treatment, styling agent, or hair growth agent, and more preferably a rinse, conditioning agent, or treatment agent. There are no particular restrictions on the dosage form of composition (2), and it can be any dosage form, such as liquid, foam, paste, cream, solid, or powder. From the viewpoint of applicability to keratin fibers, it is preferable to use a liquid, paste, or cream.

[0050] The composition (2) used in step (ii) contains components (C) and (D) described later, and has a pH of 3.5 or higher and less than 8.0. By having the pH of composition (2) within the above range, the decrease in dyeability is suppressed, the yellowing in the color after dyeing is suppressed, and good manageability is ensured. The pH of composition (2) is preferably 4.0 or higher, more preferably 4.2 or higher, even more preferably 4.3 or higher, even more preferably 4.8 or higher, and even more preferably 5.0 or higher, from the viewpoint of suppressing a decrease in dyeability and providing a yellowing suppression effect. Furthermore, from the viewpoint of suppressing damage to keratin fibers and ensuring good manageability, the pH is preferably 7.5 or lower, more preferably 7.3 or lower, and even more preferably 7.1 or lower. Also, it is preferably 4.0 to 7.5, more preferably 4.2 to 7.5, even more preferably 4.3 to 7.3, even more preferably 4.8 to 7.3, even more preferably 5.0 to 7.3, and even more preferably 5.0 to 7.1. The above pH values ​​were measured at 25°C and can be specifically measured by the method described in the examples.

[0051] <Component (C)> The composition (2) used in step (ii) contains component (C), which is a cationic surfactant. Examples of cationic surfactants of component (C) include (i) alkyltrimethylammonium salts, (ii) alkoxyalkyltrimethylammonium salts, (iii) dialkyldimethylammonium salts, (iv) alkyldimethylamines and their salts, (v) alkoxyalkyldimethylamines and their salts, and (vi) alkylamidoamines and their salts.

[0052] (i) Alkyltrimethylammonium salt Examples of alkyltrimethylammonium salts include those represented by the following general formula (2). R 13 -N + (CH3)3An - (2) [In the formula, R 13 This represents an alkyl group with 12 to 22 carbon atoms, and An - This refers to halide ions such as chloride ions and bromide ions; methosulfate ions, ethosulfate ions, methophosphate ions, etophosphate ions, methocarbonate ions, etc.

[0053] Specifically, examples include cetyltrimethylammonium chloride, stearyltrimethylammonium chloride, behenyltrimethylammonium chloride, and behenyltrimethylammonium methosulfate.

[0054] (ii) Alkoxyalkyltrimethylammonium salt Examples of alkoxyalkyltrimethylammonium salts include those represented by the following general formula (3). R 14 -OR 15 -N + (CH3)3An - (3) [In the formula, R 14R represents an alkyl group with 12 to 22 carbon atoms. 15 This represents an ethylene group or propylene group which may be substituted with a hydroxyl group, and An - This refers to halide ions such as chloride ions and bromide ions; methosulfate ions, ethosulfate ions, methophosphate ions, etophosphate ions, methocarbonate ions, etc.

[0055] Specifically, examples include stearoxypropyltrimethylammonium chloride, stearoxyethyltrimethylammonium chloride, and stearoxyhydroxypropyltrimethylammonium chloride.

[0056] (iii) dialkyldimethylammonium salt Examples of dialkyldimethylammonium salts include those represented by the following general formula (4). (R 16 )2N + (CH3)2An - (4) [In the formula, R 16 Each of these independently represents an alkyl group having 12 to 22 carbon atoms, and An - This refers to halide ions such as chloride ions and bromide ions; methosulfate ions, ethosulfate ions, methophosphate ions, etophosphate ions, methocarbonate ions, etc.

[0057] Specifically, examples include distearyldimethylammonium chloride.

[0058] (iv) Alkyldimethylamines and their salts Alkyldimethylamine reacts with acids to form quaternary ammonium salts, which act as surfactants. Therefore, here, alkyldimethylamine and its salts are defined as cationic surfactants. Furthermore, their content is calculated by the mass of alkyldimethylamine. Examples of alkyldimethylamine and its salts include those represented by the following general formula (5) and their salts. R 17-N(CH3)2(5) [In the formula, R 17 This indicates an alkyl group with 12 to 22 carbon atoms.

[0059] Examples of salts include salts made from organic or inorganic acids. Examples of organic acids include monocarboxylic acids such as acetic acid and propionic acid; dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, and phthalic acid; polycarboxylic acids such as polyglutamic acid; hydroxycarboxylic acids such as glycolic acid, lactic acid, hydroxyacrylic acid, glyceric acid, malic acid, tartaric acid, and citric acid; and acidic amino acids such as glutamic acid and aspartic acid. Examples of inorganic acids include hydrochloric acid, sulfuric acid, and phosphoric acid. Among these, organic acids are preferred, dicarboxylic acids, hydroxycarboxylic acids, and acidic amino acids are preferred, and maleic acid and succinic acid are more preferred as dicarboxylic acids. Glycolic acid, lactic acid, and malic acid are more preferred as hydroxycarboxylic acids. Glutamic acid is more preferred as an acidic amino acid.

[0060] Specific examples of alkyldimethylamines and their salts include N,N-dimethylbehenylamine, N,N-dimethylstearylamine, and their organic salts, with lactate of N,N-dimethylbehenylamine and lactate of N,N-dimethylstearylamine being preferred.

[0061] (v) Alkoxyalkyldimethylamines and their salts Alkoxyalkyldimethylamines react with acids to form quaternary ammonium salts, which act as surfactants. Therefore, here, alkoxyalkyldimethylamines and their salts are defined as cationic surfactants. Furthermore, their content is calculated by the mass of alkoxyalkyldimethylamine. Examples of alkoxyalkyldimethylamines and their salts include those represented by the following general formula (6) and their salts. R 18 -OR 19 -N(CH3)2(6) [In the formula, R 18 R represents an alkyl group with 12 to 22 carbon atoms.19 This represents an ethylene group or propylene group that may be substituted with a hydroxyl group.

[0062] Examples of salts include salts made with organic or inorganic acids. Examples of organic or inorganic acids include those used in the neutralization of alkyldimethylamine represented by the general formula (5) mentioned above.

[0063] Specific examples of alkoxyalkyldimethylamines and their salts include N,N-dimethyl-3-hexadecyloxypropylamine, N,N-dimethyl-3-octadecyloxypropylamine, and their organic salts, with lactate of N,N-dimethyl-3-hexadecyloxypropylamine and glycolate of N,N-dimethyl-3-octadecyloxypropylamine being preferred.

[0064] (vi) Alkylamidoamines and their salts Alkylamidoamines react with acids to form quaternary ammonium salts, which act as surfactants. Therefore, here, alkylamidoamines and their salts are defined as cationic surfactants. Furthermore, their content is calculated by the mass of alkylamidoamine. Examples of alkylamidoamines and their salts include those represented by the following general formula (7) and their salts. R 20 -CONH-(CH2) t -N(CH3)2(7) [In the formula, R 20 [where 't' represents an alkyl group with 12 to 22 carbon atoms, and 't' represents a number between 2 and 4.]

[0065] Among these, R 20 Preferably, the alkyl group has 14 to 22 carbon atoms. Examples of salts include salts made with organic or inorganic acids. Examples of organic or inorganic acids include those used in the neutralization of alkyldimethylamine represented by the general formula (5) mentioned above.

[0066] Specific examples of alkylamidoamines and their salts include N-(3-(dimethylamino)propyl)docosanamide and its salts, and N-(3-(dimethylamino)propyl)stearamide and its salts.

[0067] Among these, from the viewpoint of improving finger glide, (i) alkyltrimethylammonium salt, (ii) alkoxyalkyltrimethylammonium salt, (v) alkoxyalkyldimethylamine and its salt, and (vi) alkylamidoamine and its salt are preferred. Furthermore, cetyltrimethylammonium chloride, stearyltrimethylammonium chloride, N,N-dimethyl-3-hexadecyloxypropylamine and its salt, N,N-dimethyl-3-octadecyloxypropylamine and its salt, N-(3-(dimethylamino)propyl)docosanamide and its salt, and N-(3-(dimethylamino)propyl)stearamide and its salt are preferred.

[0068] The cationic surfactant of component (C) can be used individually or in combination of two or more. From the viewpoint of ensuring good finger glide, the content of component (C) in composition (2) 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, and even more preferably 1.0% by mass or more, and also preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, and even more preferably 4% by mass or less. Also preferably 0.01% by mass to 20% by mass, more preferably 0.1% by mass to 10% by mass, even more preferably 0.5% by mass to 5% by mass, and even more preferably 1.0% by mass to 4% by mass.

[0069] <Ingredient (D)> The composition (2) used in process (ii) contains component (D), which is a higher alcohol. The higher alcohol of component (D) may be aliphatic alcohol of any type, whether linear or branched, saturated or unsaturated, with a carbon number preferably 10 or more, more preferably 14 or more, even more preferably 16 or more, and preferably 22 or less, more preferably 20 or less, and even more preferably 18 or less. Specifically, examples include lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, arachidyl alcohol, hexyldecanol, isostearyl alcohol, oleyl alcohol, 2-octyldodecanol, etc. Of these, stearyl alcohol, cetyl alcohol, and myristyl alcohol are preferred. These higher alcohols can be used individually or in combination of two or more.

[0070] The content of component (D) of composition (2) in the composition is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 1.5% by mass or more, and even more preferably 2% by mass or more, and also preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 8% by mass or less. Also preferably 0.1% by mass to 20% by mass, more preferably 1% by mass to 10% by mass, even more preferably 1.5% by mass to 8% by mass, and even more preferably 2% by mass to 8% by mass. The ratio of the content of component (D) to the content of component (C) in composition (2) [component (D) / component (C)] is preferably 0.2 or more, more preferably 0.3 or more, even more preferably 0.4 or more, and also preferably 2.0 or less, more preferably 1.5 or less, and even more preferably 1.0 or less, from the viewpoint of ensuring the stability of composition (2) and good finger-feelability. It is also preferably 0.2 to 2.0, more preferably 0.3 to 1.5, and even more preferably 0.4 to 1.0.

[0071] <Other components in composition (2)> The composition (2) used in step (ii) may, in addition to the above-mentioned components, appropriately contain components commonly used in keratin fiber compositions, to the extent that it does not impair the objectives of the present invention. Examples of such components include anionic surfactants, nonionic surfactants, amphoteric surfactants, silicones, polyhydric alcohols, acids, alkaline agents, aromatic alcohols, dyes other than component (A), polymers, oils, anti-dandruff agents, vitamins, bactericides, anti-inflammatory agents, preservatives, chelating agents, humectants, pearlescent agents, ceramides, fragrances, UV absorbers, antioxidants, aqueous media, and the like. Among these, it is preferable to contain one or more selected from the group consisting of silicones, polyhydric alcohols, acids, alkaline agents, preservatives, and aqueous media.

[0072] (Silicones) The composition (2) used in step (ii) preferably contains silicones in terms of smoothness when dry. Examples of such silicones are listed below.

[0073] (1) Dimethylpolysiloxane For example, one example is that which can be expressed by the following general formula (8). (CH3)3SiO-[(CH3)2SiO] b -Si(CH3)3(8) [In equation (8), b represents a number between 3 and 20,000.]

[0074] (2) Amino-modified silicone The amino-modified silicone may be in any form, such as an oil, emulsion, or a solution diluted with low-viscosity silicone or liquid paraffin. Preferred amino-modified silicones are those listed in the 10th edition of the INCI Dictionary (International Cosmetic Ingredient Dictionary and Handbook) under the names amodimethicone, aminoethylaminopropyl dimethicone, or aminopropyl dimethicone. This amino-modified silicone is preferably used as an aqueous emulsion. Examples of commercially available amodimethicone include "DOWSIL SM8904," "DOWSIL CB-1002" (both manufactured by Dow-Toray Industries, Inc.), "KT-0032," and "XF42-B8922" (both manufactured by Momentive Performance Materials, Inc.).

[0075] (3) Other silicones Other examples include polyether-modified silicones, methylphenylpolysiloxanes, fatty acid-modified silicones, alcohol-modified silicones, alkoxy-modified silicones, epoxy-modified silicones, fluorine-modified silicones, cyclic silicones, alkyl-modified silicones, and the like.

[0076] Silicones can be used individually or in combination of two or more types. If composition (2) contains silicones, the content of silicones in composition (2) is preferably 0.01% by mass or more, more preferably 0.015% by mass or more, even more preferably 0.02% by mass or more, and also preferably 10% by mass or less, more preferably 6% by mass or less, and even more preferably 3% by mass or less, from the viewpoint of ensuring good finger-feelability. Furthermore, it is preferably 0.01% by mass to 10% by mass, more preferably 0.01% by mass to 6% by mass, even more preferably 0.015% by mass to 6% by mass, and even more preferably 0.02% by mass to 3% by mass.

[0077] (Polyhydric alcohol) Examples of polyhydric alcohols include those with 2 to 20 carbon atoms, specifically alkylene glycols such as ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, and hexylene glycol; glycerin compounds such as glycerin, diglycerin, and polyglycerin; sugar alcohols such as xylitol, mannitol, galactite, and sorbitol; and others such as pentaerythritol and pentadiol. Of these, one or more selected from the group consisting of propylene glycol, dipropylene glycol, 1,3-butylene glycol, glycerin, and dipropylene glycol are particularly preferred. Polyhydric alcohols can be used alone or in combination of two or more types. When using polyhydric alcohols, the polyhydric alcohol content in composition (2) is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and also preferably 20% by mass or less, and more preferably 8% by mass or less, from the viewpoint of feel during and after use, as well as applicability and usability. Furthermore, it is preferably 0.1% to 20% by mass, and more preferably 0.5% to 8% by mass.

[0078] (acid) Composition (2) may contain an acid from the viewpoint of repairing damaged keratin fibers. A weak acid is preferred as the acid because it allows for easy pH adjustment. Specific examples of weak acids include carboxylic acids such as citric acid, glycolic acid, succinic acid, tartaric acid, lactic acid, acetic acid, fumaric acid, malic acid, levulinic acid, butyric acid, valeric acid, oxalic acid, maleic acid, and mandelic acid, as well as phosphoric acid. It is even more preferable to combine these acids with their potassium and sodium salts to give the system balancing ability. Of these, carboxylic acids are preferred from the viewpoint of odor and irritancy, and lactic acid is more preferred. If composition (2) further contains acid, the acid content in composition (2) is preferably 3.0% by mass or less, more preferably 2.5% by mass or less, even more preferably 1.5% by mass or less, even more preferably 1.0% by mass or less, and even more preferably 0.6% by mass or less, from the viewpoint of ensuring good combability and providing a yellowing suppression effect. However, from the viewpoint of providing a yellowing-suppressing effect, it is preferable that composition (2) substantially does not contain acid, and more preferably that the acid content in composition (2) is 0% by mass.

[0079] Furthermore, if composition (2) also contains acid, from the viewpoint of ensuring good finger glide and providing a yellowing suppression effect, the ratio of the acid content in composition (2) to the content of component (A) in composition (1) [(acid) / component (A)] is preferably 30 or less, more preferably 20 or less, even more preferably 15 or less, even more preferably 10 or less, and even more preferably 5 or less.

[0080] (Alkaline agent) Composition (2) may contain an alkaline agent from the viewpoint of adjusting the pH of the formulation. Examples of the alkaline agent include ammonia; alkanolamines such as mono-, di-, or triethanolamine; alkylamines such as methylamine, dimethylamine, ethylamine, diethylamine, N-methylethylamine, propylamine, and butylamine; aralkylamines such as benzylamine; and inorganic alkali compounds such as sodium hydroxide and potassium hydroxide. One or more of these can be used. From the viewpoint of water solubility, the number of carbon atoms in the alkanolamine, alkylamine, or aralkylamine is preferably 10 or less, more preferably 8 or less. In particular, from the viewpoint of ease of pH adjustment, the alkaline agent is preferably one or more selected from the group consisting of ammonia, alkanolamines, alkylamines, aralkylamines, sodium hydroxide, and potassium hydroxide, more preferably containing one or more selected from the group consisting of ammonia and alkanolamines, even more preferably containing monoalkanolamines, and even more preferably containing monoethanolamines.

[0081] If composition (2) contains an alkaline agent, the amount of alkaline agent in composition (2) is preferably 3% by mass or less, more preferably 1% by mass or less, and even more preferably 0.5% by mass or less, from the viewpoint of formulation stability.

[0082] (Preservative) Composition (2) may contain a preservative. Examples of such preservatives include methyl parahydroxybenzoate (p-hydroxybenzoate), isopropylmethylphenol, phenoxyethanol, dehydroacetic acid, and their salts. If composition (2) contains a preservative, the amount of preservative in composition (2) is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and also preferably 5% by mass or less, more preferably 2% by mass or less, and even more preferably 1% by mass or less. Furthermore, it is preferably 0.01% to 5% by mass, more preferably 0.05% to 2% by mass, and even more preferably 0.05% to 1% by mass.

[0083] (aqueous medium) Composition (2) typically contains an aqueous medium. Examples of aqueous media include those exemplified in Composition (1), with water being preferred. If composition (2) contains an aqueous medium, the content of the aqueous medium in composition (2) can be appropriately selected depending on the dosage form of composition (2), but is usually in the range of 1 to 95% by mass. When water is used as the aqueous medium, from the viewpoint of ensuring applicability to keratin fibers, stability of composition (2), and good finger-feel, the water content in composition (2) is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, and also preferably 95% by mass or less, more preferably 90% by mass or less. Furthermore, it is preferably 50% to 95% by mass, more preferably 60% to 95% by mass, even more preferably 70% to 90% by mass, and even more preferably 80% to 90% by mass.

[0084] The method for producing composition (2) is not particularly limited. For example, it can be produced by blending components (C), (D), and other components as needed using the method described in the examples, and mixing them using a known stirring device or the like.

[0085] [Keratin Fiber Staining Method] The present invention further provides a method for dyeing keratin fibers, comprising the steps of applying composition (1) to keratin fibers and applying composition (2) to keratin fibers in that order. The step of applying composition (1) to keratin fibers may be the same as the step (i) described above. The step of applying composition (2) to keratin fibers may be the same as the step (ii) described above. Furthermore, in the above keratin fiber dyeing method, similar to the above keratin fiber treatment method, steps (i-1) to (i-3) described above may be included between the step of applying composition (1) to keratin fibers and the step of applying composition (2) to keratin fibers. Furthermore, in the above keratin fiber dyeing method, similar to the above keratin fiber treatment method, if composition (2) is used in a leave-off form, steps (ii-1) to (ii-2) described above may be included after the step of applying composition (2) to keratin fibers, and if composition (2) is used in a leave-on form, step (ii-2) may be included.

[0086] As one embodiment of the present invention, the present invention also provides a method for dyeing keratin fibers, comprising the steps of applying composition (1) as a cleaning agent to keratin fibers and applying composition (2) to keratin fibers as one or more selected from the group consisting of rinse agents, conditioning agents, and treatment agents. That is, composition (1), which is a cleaning agent, is applied to keratin fibers, lathered up to wash the keratin fibers, and then rinsed with water. Then, composition (2), which is one or more selected from the group consisting of rinse agents, conditioning agents, and treatment agents, is applied to the keratin fibers, left for a short time (about 1 to 5 minutes) as needed, and then rinsed with water. By repeating the above steps on a daily basis, keratin fibers can be dyed easily and in a short period of time, and the yellowish tint of the dyed color can be suppressed.

[0087] [Keratin Fiber Composition Kit] The present invention also provides a keratin fiber composition kit comprising the following components. Specifically, the keratin fiber composition kit comprises a composition (1) containing the above components (A) and (B) with a pH of 8.0 to 12.0, and a composition (2) containing the above components (C) and (D) with a pH of 3.5 to less than 8.0. The above-mentioned keratin fiber composition kit can be provided in a form in which, for example, composition (1) and composition (2) are each housed in separate containers, and these containers are then combined into a set. In another embodiment, the keratin fiber composition kit may have a container that is divided into at least two compartments, wherein composition (1) is contained in a first compartment and composition (2) is contained in a second compartment different from the first compartment.

[0088] With regard to the embodiments described above, the present invention discloses a method for treating keratin fibers, a composition kit for keratin fibers, and a method for dyeing keratin fibers. <1> A method for treating keratin fibers, comprising the following steps (i) and (ii) in order. Step (i): A step of applying a composition (1) containing the following components (A) and (B) and having a pH of 8.0 or higher and 12.0 or lower to keratin fibers. (A) Compounds represented by general formula (1) or salts thereof [ka] [In equation (1), the dashed line indicates the presence or absence of a π bond, R 1 R represents a hydroxyl group or an acetoxy group. 2 R represents a hydrogen atom or a -COOR group (where R is a hydrogen atom, a methyl group, or an ethyl group), 3 [This represents a hydrogen atom, an acetyl group, a methyl group, or an ethyl group.] (B) Alkaline agent Step (ii): A step of applying a composition (2) containing the following components (C) and (D) and having a pH of 3.5 or higher and less than 8.0 to keratin fibers. (C) Cationic surfactant (D) Higher alcohol <2> The pH of composition (1) is 8.5 to 11.0, preferably 8.8 to 10.5, and more preferably 9.0 to 10.0. <1> A method for processing keratin fibers. <3> The pH of composition (2) is 4.0 to 7.5, preferably 4.2 to 7.5, more preferably 4.3 to 7.3, even more preferably 4.8 to 7.3, even more preferably 5.0 to 7.3, and still more preferably 5.0 to 7.1. <1> or <2> A method for processing keratin fibers. <4> A method for treating keratin fibers, comprising the following steps (i) and (ii) in order. Step (i): A step of applying a composition (1) containing the following components (A) and (B) and having a pH of 8.5 to 11.0 to keratin fibers. (A) Compound represented by general formula (1) or a salt thereof 0.05 to 3% by mass [ka] [In equation (1), the dashed line indicates the presence or absence of a π bond, R1 R represents a hydroxyl group or an acetoxy group. 2 R represents a hydrogen atom or a -COOR group (where R is a hydrogen atom, a methyl group, or an ethyl group), 3 [This represents a hydrogen atom, an acetyl group, a methyl group, or an ethyl group.] (B) Alkaline agent 0.1-5% by mass Step (ii): A step of applying a composition (2) containing the following components (C) and (D) and having a pH of 4.2 to 7.5 to keratin fibers. (C) Cationic surfactant 0.1-10% by mass (D) Higher alcohols 1-10% by mass <5> A method for treating keratin fibers, comprising the following steps (i) and (ii) in order. Step (i): A step of applying a composition (1) containing the following components (A) and (B) and having a pH of 8.8 to 10.5 to keratin fibers. (A) Compound represented by general formula (1) or its salt 0.1 to 1.0% by mass [ka] [In equation (1), the dashed line indicates the presence or absence of a π bond, R 1 R represents a hydroxyl group or an acetoxy group. 2 R represents a hydrogen atom or a -COOR group (where R is a hydrogen atom, a methyl group, or an ethyl group), 3 [This represents a hydrogen atom, an acetyl group, a methyl group, or an ethyl group.] (B) Alkaline agent 0.5-3% by mass Step (ii): A step of applying a composition (2) containing the following components (C) and (D) and having a pH of 5.0 to 7.3 to keratin fibers. (C) Cationic surfactant 0.5-5% by mass (D) Higher alcohols 2-8% by mass <6> Composition (2) further contains an acid, wherein the acid content in composition (2) is 3.0% by mass or less, preferably 2.5% by mass or less, more preferably 1.5% by mass or less, even more preferably 1.0% by mass or less, and even more preferably 0.6% by mass or less. <1> ~ <5> A method for treating keratin fibers as described in any of the following. <7> The ratio of the content of acid in composition (2) to the content of component (A) in composition (1) [(acid) / component (A)] is preferably 30 or less, 20 or less, more preferably 15 or less, even more preferably 10 or less, and even more preferably 5 or less. <6> The keratin fiber treatment method described above. <8> Composition (2) is substantially acid-free. <1> ~ <5> A method for treating keratin fibers as described in any of the following. <9> Component (B) is one or more selected from the group consisting of ammonia and alkanolamines. <1> ~ <8> A method for treating keratin fibers as described in any of the following. <10> Composition (1) further contains an antioxidant as component (E). <1> ~ <9> A method for treating keratin fibers as described in any of the following. <11> Component (E) contains one or more selected from the group consisting of L-ascorbic acid, sulfite, pyrosulfite, bisulfite or salts thereof, ascorbic acid glucoside, and sulfur dioxide. <10> The keratin fiber treatment method described above. <12> Composition (1) further contains an anionic surfactant as component (F). <1> ~ <11> A method for treating keratin fibers as described in any of the following. <13> Composition (1) is a detergent. <1> ~ <12> A method for treating keratin fibers as described in any of the following. <14> Composition (2) is a rinse agent, a conditioning agent, or a treatment agent. <1> ~ <13> A method for treating keratin fibers as described in any of the following. <15> Between step (i) and step (ii), there is a step of rinsing the keratin fibers with water. <1> ~ <14> A method for treating keratin fibers as described in any of the following. <16> After the rinsing step, the material is subjected to step (ii) while maintaining a moist state. <15> The keratin fiber treatment method described above. <17> Between process (i) and process (ii), there are the following processes (i-1), (i-2), and (i-3). <1> ~ <14> A method for treating keratin fibers as described in any of the following. Step (i-1): One of the following steps: applying composition (1) and letting it stand, foaming composition (1), or foaming composition (1) and then letting it stand. Step (i-2): A step of rinsing the composition (1) on the keratin fibers with water. Process (i-3): Process for drying keratin fibers <18> The material is subjected to process (ii) while maintaining a moist state. <17> The keratin fiber treatment method described above. <19> The process includes step (ii-1) of washing off the composition (2) on the keratin fibers with water after step (ii). <1> ~ <17> A method for treating keratin fibers as described in any of the following. <20> The process includes a step (ii-2) in which the keratin fibers are dried after step (ii-1). <19> The keratin fiber treatment method described above. <21> The process is followed by a step (ii-2) in which the keratin fibers are dried. <1> ~ <18> A method for treating keratin fibers as described in any of the following. <22> This is a method for staining keratin fibers. <1> ~ <21> A method for treating keratin fibers as described in any of the following. <23> A keratin fiber composition kit comprising: composition (1) containing the following components (A) and (B) and having a pH of 8.0 to 12.0; and composition (2) containing the following components (C) and (D) and having a pH of 3.5 to less than 8.0. (A) Compounds represented by general formula (1) or salts thereof [ka] [In equation (1), the dashed line indicates the presence or absence of a π bond, R 1 R represents a hydroxyl group or an acetoxy group. 2 R represents a hydrogen atom or a -COOR group (where R is a hydrogen atom, a methyl group, or an ethyl group), 3 [This represents a hydrogen atom, an acetyl group, a methyl group, or an ethyl group.] (B) Alkaline agent (C) Cationic surfactant (D) Higher alcohol <24> The pH of composition (1) is 8.5 to 11.0, preferably 8.8 to 10.5, and more preferably 9.0 to 10.0. <23> A kit for keratin fiber composition. <25> The pH of composition (2) is 4.0 to 7.5, preferably 4.2 to 7.5, more preferably 4.3 to 7.3, even more preferably 4.8 to 7.3, even more preferably 5.0 to 7.3, and still more preferably 5.0 to 7.1. <23> or <24> A kit for keratin fiber composition. <26> A keratin fiber composition kit comprising: composition (1) containing the following components (A) and (B) and having a pH of 8.5 to 11.0; and composition (2) containing the following components (C) and (D) and having a pH of 4.2 to 7.5. (A) Compound represented by general formula (1) or a salt thereof 0.05 to 3% by mass [ka] [In equation (1), the dashed line indicates the presence or absence of a π bond, R 1 R represents a hydroxyl group or an acetoxy group. 2 R represents a hydrogen atom or a -COOR group (where R is a hydrogen atom, a methyl group, or an ethyl group), 3 [This represents a hydrogen atom, an acetyl group, a methyl group, or an ethyl group.] (B) Alkaline agent 0.1-5% by mass (C) Cationic surfactant 0.1-10% by mass (D) Higher alcohols 1-10% by mass <27> A keratin fiber composition kit comprising: composition (1) containing the following components (A) and (B) and having a pH of 8.8 to 10.5; and composition (2) containing the following components (C) and (D) and having a pH of 5.0 to 7.3. (A) Compound represented by general formula (1) or a salt thereof 0.1 to 1.0 mass [ka] [In equation (1), the dashed line indicates the presence or absence of a π bond, R 1 R represents a hydroxyl group or an acetoxy group. 2 R represents a hydrogen atom or a -COOR group (where R is a hydrogen atom, a methyl group, or an ethyl group), 3 [This represents a hydrogen atom, an acetyl group, a methyl group, or an ethyl group.] (B) Alkaline agent 0.5-3% by mass (C) Cationic surfactant 0.5-5% by mass (D) Higher alcohols 2-8% by mass <28> Composition (2) further contains an acid, wherein the acid is 3.0% by mass or less, preferably 2.5% by mass or less, more preferably 1.5% by mass or less, even more preferably 1.0% by mass or less, and even more preferably 0.6% by mass or less in composition (2). <23> ~ <27> A method for treating keratin fibers as described in any of the following. <29> The ratio of the content of acid in composition (2) to the content of component (A) in composition (1) [(acid) / component (A)] is preferably 30 or less, 20 or less, more preferably 15 or less, even more preferably 10 or less, and even more preferably 5 or less. <28> The keratin fiber treatment method described above. <30> Composition (2) is substantially acid-free. <23> ~ <27> A method for treating keratin fibers as described in any of the following. [Examples]

[0089] The following describes examples of the present invention, but the present invention is not limited to the scope of these examples. In these examples, pH measurement and staining evaluation were performed by the following methods. [pH measurement] The pH of the keratin fiber composition at 25°C was measured using a pH meter (F-51, manufactured by Horiba, Ltd.).

[0090] [Staining evaluation] For evaluating dyeability, a 1g bundle of goat hair (10cm, manufactured by Viewlux Co., Ltd.) with an L value of 85.1-86.1, an a value of 0.5-1.0, and a b value of 12.2-13.4 was used. The goat hair bundles, which had been pre-wetted by rinsing them with warm water (40°C) for 15 seconds, were then coated with composition (1) in a bath ratio of 1:1:0.2 (goat hair bundle:water:composition (1)). After letting it sit for 30 seconds, it was lathered for 30 seconds, and then rinsed with warm water (40°C) for 30 seconds. Next, the rinsed goat hair was lightly squeezed to remove excess water, and immediately afterwards, composition (2) was applied in a bath ratio of 1:1:0.2 (goat hair bundle:water:composition (2)). After letting it sit for 60 seconds, it was rinsed with warm water (40°C) for 30 seconds. This procedure was repeated 10 times, and then the goat hair was dried. The hue (L) of the goat hair bundle before the dyeing treatment and the goat hair bundle after the dyeing treatment. * , a * , b * The color difference ΔE was calculated using a colorimeter (CR-400, Konica Minolta, Inc.) at 6 points per bundle of goat hair, and the average value was obtained. Using this average value, the color difference ΔE was calculated according to the following formula (9). A larger value of ΔE indicates better dyeability. In addition, the saturation (C) was calculated according to the following formula (10). * ) was calculated. ΔE = [(ΔL * ) 2 +(Δa * ) 2 +(Δb * ) 2 ] 1 / 2 ...Equation (9) (Δ: Change in hue before and after staining) C * = [(a * ) 2 +(b * ) 2 1 / 2 ···Formula (10)

[0091] [Color Tone Evaluation] For color tone evaluation, five professional panelists ranked whether goat hair after dyeing treatment had a yellowish tint or not according to the following five grades, and the evaluation level selected by the largest number of panelists among A to E was taken as the evaluation of the tested goat hair bundle. ·A: Natural gray with no yellowish tint perceived at all ·B: Gray with almost no yellowish tint perceived ·C: A slight yellowish tint is perceived, but at an acceptable level ·D: Light gray with a somewhat noticeable yellowish tint ·E: A strong yellowish tint is perceived

[0092] [Finger Combing Evaluation] For the finger combing evaluation, hair bundles dyed by the following method were used. First, to a hair bundle of 10 cm in length, 10 g in mass obtained from a Japanese female's black hair tress, Blaune Cream Hair Color No. 6 (manufactured by Kao Corporation) as a hair dye was applied to achieve a bath ratio of 1:1 (hair bundle: hair dye), left to stand at 30°C for 15 minutes, and rinsed with warm water (40°C) for 30 seconds. Further, the hair bundle after the above treatment was washed with a commercially available shampoo (Essential, manufactured by Kao Corporation) and rinsed with warm water (40°C), and this operation was repeated twice. After that, the hair bundle was air-dried to obtain a dyed hair bundle. The above dyed hair bundle, which had been pre-rinsed with warm water (40°C) for 15 seconds and wetted, was applied with Composition (1) to achieve a bath ratio of 1:1:0.2 (hair bundle:water:Composition (1)), allowed to blend for 30 seconds, then lathered for 30 seconds, and rinsed with warm water (40°C) for 30 seconds. Next, the rinsed hair bundle was lightly squeezed, and without drying, Composition (2) was immediately applied to achieve a bath ratio of 1:1:0.2 (hair bundle:water:Composition (2)), allowed to blend for 60 seconds, and then rinsed with warm water (40°C) for 30 seconds. ​Five expert panelists evaluated the hair strands after the above treatment, ranking them on a six-point scale. The score that received the most votes from the panelists (out of 5 to 0) was used as the hair strand's score. A score of 3 or higher is desirable. 5 points: Soft and smooth to the touch. 4 points: Smooth feel 3 points: Smooth to the touch with no squeaking sensation. 2 points: The texture feels slightly rough to the touch. • 1 point: The fibers feel very stiff and rough to the touch. • 0 points: Hair is tangled and you can't run your fingers through it.

[0093] [Preparation of Composition (1A)] Composition (1), a detergent, was prepared as follows, with the composition shown in Table 1. First, the components listed in Table 1, excluding the 5,6-dihydroxyindole solution and L-ascorbic acid, were mixed and uniformly dissolved to obtain a mixed solution. Next, L-ascorbic acid was mixed into the mixed solution under a nitrogen atmosphere, and then the 5,6-dihydroxyindole solution was added to prepare composition (1A). All amounts (parts by mass) listed in Table 1 are in their original form.

[0094] [Preparation of composition (2A)] Composition (2), a conditioning agent, was prepared as follows, with the composition shown in Table 1. First, methyl p-hydroxybenzoate was added to purified water and then heated to 80°C to dissolve it, obtaining an aqueous solution of methyl p-hydroxybenzoate. Next, distearyldimethylammonium chloride, stearyltrimethylammonium chloride, cetearyl alcohol, and propylene glycol were heated to 80°C and mixed. This mixed solution was added to the aqueous solution of methyl p-hydroxybenzoate and mixed uniformly, after which the temperature was lowered to 35°C. Then, a high-molecular-weight aminoethylaminopropylmethylsiloxane-dimethylsiloxane copolymer emulsion was mixed, followed by lactic acid and monoethanolamine to prepare composition (2A) with a pH of 4.2. All formulation amounts (parts by mass) listed in Table 1 are in crystalline form.

[0095] [Preparation of compositions (2B) and (2C)] Compositions (2B) and (2C) were prepared using the same procedure as for composition (2A), except that the amount of lactic acid was changed to 0.85 parts by mass and 0.79 parts by mass, respectively. Composition (2B) had a pH of 5.3 and composition (2C) had a pH of 7.1.

[0096] [Preparation of composition (2D)] Composition (2D) was prepared using the same procedure as composition (2A), except that the amount of monoethanolamine was changed to 1.0 part by mass and the amount of lactic acid was changed to 2.98 parts by mass, resulting in composition (2D) with a pH of 4.1.

[0097] [Preparation of Composition (2E)] Composition (2E) was prepared using the same procedure as composition (2A), except that monoethanolamine and lactic acid were not used, to obtain composition (2E) with a pH of 4.9.

[0098] [Preparation of compositions (2F) and (2G)] Compositions (2F) and (2G) were prepared using the same procedure as for composition (2A), except that the amount of lactic acid was changed to 0.75 parts by mass and 4.73 parts by mass, respectively. Composition (2F) had a pH of 8.2 and composition (2G) had a pH of 3.1.

[0099] The prepared compositions (1A) and (2A) to (2G) were stored under a nitrogen atmosphere and sampled each time for pH measurement, staining evaluation, color evaluation, and finger-feel evaluation. The composition and pH of composition (1A) and the composition and pH of compositions (2A) to (2G) are shown in Table 1.

[0100] [Examples 1-5, Comparative Examples 1 and 2] Examples 1 to 5 were created using composition (1A) and compositions (2A) to (2E), respectively, while Comparative Examples 1 and 2 were created using composition (1A) and compositions (2F) and (2G), respectively. Dyeability, color, and smoothness were evaluated for each. The results are shown in Table 1.

[0101] [Table 1]

[0102] The components listed in the table are shown below. Note that the amounts (parts by mass) of each component in the table are in their natural form. *1: 5,6-dihydroxyindole solution: A solution prepared by the method described in Japanese Patent Publication No. 5570161 (5,6-dihydroxyindole: 1% by mass, 5,6-dihydroxyindole-2-carboxylic acid: 0.14% by mass, ethanol: 20% by mass, water: remainder) *2: Sodium polyoxyethylene lauryl ether sulfate; Emal E-27C (manufactured by Kao Corporation, active ingredient content: 27.0% by mass, water: 71.7% by mass) *3: Phosphoric acid; aqueous solution with a phosphoric acid concentration of 75% by mass. *4: Purified water; adjust the amount so that the total volume is 100 parts by mass. *5: Distearyldimethylammonium chloride; Cotamin D86P (manufactured by Kao Corporation, active ingredient content: 75% by mass, water: remainder) *6: Stearyltrimethylammonium chloride; Cotamin 86W (manufactured by Kao Corporation, active ingredient content: 28% by mass, water: remainder) *7: High-molecular-weight aminoethylaminopropylmethylsiloxane / dimethylsiloxane copolymer emulsion; silicone KT-0032 (manufactured by Momentive Performance Materials Japan LLC, active ingredient content: 40% by mass, water: 49% by mass) *8: Lactic acid; aqueous solution of lactic acid with a concentration of 90% by mass. *9: Purified water; adjust the amount so that the total volume is 100 parts by mass.

[0103] In this embodiment, the color of the keratin fiber treatment method of the present invention was evaluated by color measurement and visual inspection to determine whether it was dyed to a natural gray color. For the evaluation of the color measurement values, the b of the color measurement value was used. * The larger the value, the more yellowish it is. However, b *Even if the value of is small, if the saturation increases, an unnatural color that is different from the inherently achromatic gray can be perceived. Therefore, in this invention, the colorimetric value is b * A value close to 0 and a low saturation are preferable.

[0104] From Table 1, the following can be seen: As shown in Examples 1-5, the keratin fiber treatment method of the present invention exhibits high dyeability, resulting in a natural gray color with minimal yellowing. Furthermore, the dyed result after repeating washing with composition (1) and conditioning with composition (2) 10 times is a natural gray. In addition, the keratin fibers can be made to feel smooth to the touch after going through steps (i) using composition (1) and step (ii) using composition (2). A comparison of Examples 1-3 with Comparative Example 1, which has the same composition as Examples 1-3 except that the pH of composition (2) was set to over 8.0 by changing the amount of lactic acid, shows that when the pH of composition (2) is over 8.0, there is no significant difference in dyeability and the color is good even after repeating washing with composition (1) and conditioning with composition (2) 10 times. However, the keratin fibers become less manageable after going through steps (i) using composition (1) and step (ii) using composition (2). A comparison of Examples 1-3 with Comparative Example 2, which has the same composition as Examples 1-3 except that the pH of composition (2) was lowered to less than 3.5 by changing the amount of lactic acid, shows that when the pH of composition (2) is less than 3.5, the keratin fibers are smooth to the touch after going through steps (i) using composition (1) and (ii) using composition (2). However, after repeating washing with composition (1) and conditioning with composition (2) 10 times, the dyeability decreases significantly and the fibers take on a yellowish tint.

[0105] In this specification, as one embodiment of the present invention, Formulation Examples 1 to 6 are disclosed in Table 2 below. [Table 2]

[0106] The components listed in the table are shown below. Note that the amounts (parts by mass) of each component in the table are in their natural form. *11: 5,6-dihydroxyindole solution: A solution prepared by the method described in Japanese Patent Publication No. 5570161 (5,6-dihydroxyindole: 1% by mass, 5,6-dihydroxyindole-2-carboxylic acid: 0.14% by mass, ethanol: 20% by mass, water: remainder) *12: 5,6-dihydroxyindoline hydrobromide solution (manufactured by AK-scientific, 5,6-dihydroxyindoline hydrobromide: 1% by mass, ethanol: 20% by mass, water: remainder) *13: Sodium polyoxyethylene lauryl ether sulfate; Emal E-27C (manufactured by Kao Corporation, active ingredient content: 27.0% by mass, water: 71.7% by mass) *14: Phosphoric acid; aqueous solution with a phosphoric acid concentration of 75% by mass. *15: Amphoteric surfactant (lauric acid amidopropyl betaine); Amhitol 20AB (manufactured by Kao Corporation, active ingredient content: 28.8% by mass, water: 64.0% by mass) *16: 2-Alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine; Amhithol 20Y-B (manufactured by Kao Corporation, active ingredient content: 40.0% by mass, water: 42.0% by mass) *17: O-[2-hydroxy-3-(trimethyl / lauryldimethylammonio)propyl]hydroxyethylcellulose chloride; Softcat Polymer SL-30 (manufactured by The Dow Chemical Company, active ingredient content: 91.0% by mass, water: 5.0% by mass) *18: O-[2-hydroxy-3-(trimethylammonio)propyl]guar gum chloride (cationized guar gum); Jaguar Excel (Solvay (Novecare)) *19: Dimethyldiallylammonium chloride / acrylic acid copolymer solution; MERQUAT 280NP POLYMER (manufactured by Lubrizol Advanced Materials, Inc., active ingredient content: 41.0% by mass, water: remainder) *20: Purified water; adjust the amount so that the total volume is 100 parts by mass. *21: Distearyldimethylammonium chloride; Cotamin D86P (manufactured by Kao Corporation, active ingredient content: 75% by mass, water: remainder) *22: Stearyltrimethylammonium chloride; Cotamin 86W (manufactured by Kao Corporation, active ingredient content: 28% by mass, water: remainder) *23: High-molecular-weight aminoethylaminopropylmethylsiloxane / dimethylsiloxane copolymer emulsion; silicone KT-0032 (manufactured by Momentive Performance Materials Japan LLC, active ingredient content: 40% by mass, water: 49% by mass) *24: Lactic acid; aqueous solution of lactic acid with a concentration of 90% by mass. *25: Sodium hydroxide; an aqueous solution of sodium hydroxide with a concentration of 48% by mass, with the amount adjusted so that the pH is 5.0. *26: Purified water; adjust the amount so that the total volume is 100 parts by mass. [Industrial applicability]

[0107] According to the present invention, by sequentially applying a first composition that gradually dyes keratin fibers and also has the function of washing hair, such as a shampoo, to keratin fibers, and a second composition that provides effects such as conditioning or treatment, it is possible to suppress the decrease in dyeability, gradually dye the keratin fibers to their original color, which is less yellowish and is expressed when melanin precursors are oxidized, and moreover, to improve the manageability of the hair, a method for treating keratin fibers can be obtained.

Claims

1. A method for treating keratin fibers, comprising the following steps (i) and (ii) in order. Step (i): A step of applying a composition (1) containing the following components (A) and (B) and having a pH of 8.0 or higher and 12.0 or lower to keratin fibers. (A) Compound represented by general formula (1) or a salt thereof, in a concentration of 0.05% to 5% by mass in composition (1) 【Chemistry 1】 [In equation (1), the dashed line indicates the presence or absence of a π bond, R １ R represents a hydroxyl group or an acetoxy group. ２ R represents a hydrogen atom or -COOR (where R is a hydrogen atom, a methyl group, or an ethyl group), ３ [This represents a hydrogen atom, an acetyl group, a methyl group, or an ethyl group.] (B) Alkaline agent 0.01% to 10% by mass in composition (1) Step (ii): A step of applying composition (2), which contains the following components (C) and (D) and has a pH of 4.0 to 7.5, to keratin fibers. (C) Cationic surfactant 0.01% to 20% by mass in composition (2) (D) Higher alcohols 0.1% to 20% by mass in composition (2)

2. The keratin fiber treatment method according to claim 1, wherein component (B) is one or more selected from the group consisting of ammonia and alkanolamines.

3. The method for treating keratin fibers according to claim 1 or 2, wherein component (D) is an aliphatic alcohol having 10 to 22 carbon atoms.

4. The method for treating keratin fibers according to any one of claims 1 to 3, wherein composition (1) further contains an antioxidant as component (E).

5. The keratin fiber treatment method according to claim 4, wherein component (E) contains one or more selected from the group consisting of L-ascorbic acid, sulfite, pyrosulfite, bisulfite or salts thereof, ascorbic acid glucoside, and sulfur dioxide.

6. The method for treating keratin fibers according to any one of claims 1 to 5, wherein composition (1) further contains an anionic surfactant as component (F).

7. A method for treating keratin fibers according to any one of claims 1 to 6, wherein composition (1) is a detergent.

8. A method for treating keratin fibers according to any one of claims 1 to 7, wherein composition (2) is a rinse agent, a conditioning agent, or a treatment agent.

9. A method for treating keratin fibers according to any one of claims 1 to 8, further comprising a step of rinsing the keratin fibers with water between step (i) and step (ii).

10. A method for treating keratin fibers according to any one of claims 1 to 9, which is a method for dyeing keratin fibers.

11. Composition (1) containing the following components (A) and (B) and having a pH of 8.0 to 12.0, and Composition (2) containing the following components (C) and (D) and having a pH of 4.0 to 7.

5. A keratin fiber composition kit comprising the following components. (A) Compound represented by general formula (1) or a salt thereof, in a concentration of 0.05% to 5% by mass in composition (1) 【Chemistry 2】 [In equation (1), the dashed line indicates the presence or absence of a π bond, R １ R represents a hydroxyl group or an acetoxy group. ２ R represents a hydrogen atom or -COOR (where R is a hydrogen atom, a methyl group, or an ethyl group), ３ [This represents a hydrogen atom, an acetyl group, a methyl group, or an ethyl group.] (B) Alkaline agent 0.01% to 10% by mass in composition (1) (C) Cationic surfactant 0.01% to 20% by mass in composition (2) (D) Higher alcohols 0.1% to 20% by mass in composition (2)

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