Human hair dyeing stimulant

Abstract

To provide a hair dyeing promoter for human hair that can enhance the dyeability of hair dyeing compositions. [Solution] A hair dyeing accelerant for human hair containing a cationic polymer.

Description

[Technical Field]

[0001] This disclosure relates to a hair dyeing stimulant for human hair. [Background technology]

[0002] 5,6-dihydroxyindole (hereinafter also referred to as "DHI"), a melanin precursor, and its derivatives have the property of developing color and becoming melanin through polymerization by air oxidation, and air oxidation type hair dye compositions that utilize this property are known. Since melanin precursors have a lower molecular weight than melanin, they have the advantage of penetrating hair more easily than melanin.

[0003] Regarding hair dyeing compositions containing DHI or its derivatives, for example, Patent Document 1 discloses an air-oxidizing hair dye composition containing (A) 5,6-dihydroxyindole, 5,6-dihydroxyindole-2-carboxylic acid or salts thereof, (B) alkanolamine, (C) ascorbic acid or its salt, (D) sulfite, and (E) water, with a pH of 10 or more and 11 or less at 25°C. Patent Document 2 also discloses a one-component hair dye composition with a pH of 8 to 11 containing (A) a specific DHI or its derivative, (B) silicones, and (C) polyhydric alcohol. Furthermore, Patent Document 3 discloses an air-oxidizing hair dye comprising (A) an acidic agent containing a melanin precursor and (B) a reducing agent, and (C) an alkaline agent containing an alkaline agent, wherein one or more of the agents contain (D) a nonionic or anionic direct dye, and the agents are applied to the hair simultaneously, and the total alkalinity when the agents are mixed is 3.0 ml / g or less. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2009-137877 [Patent Document 2] Japanese Patent Publication No. 2007-326812

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] A hair dye composition containing DHI or its derivative that has been conventionally used may not have sufficient dyeability with DHI or its derivative. For example, in a conventional hair dye composition containing DHI or its derivative, it may be necessary to perform hair dyeing multiple times in order to exhibit excellent hair dyeing properties.

[0006] An object of the present disclosure is to provide a hair dyeing accelerator for human hair that can enhance the hair dyeing property of a hair dye composition.

Means for Solving the Problems

[0007] The present inventors have found that a hair dyeing accelerator containing a cationic polymer can improve the hair dyeing property of a hair dye composition, and for example, can enhance the hair dyeing property of a hair dye composition containing 5,6-dihydroxyindoles, 5,6-dihydroxyindolines or their salts.

[0008] The present disclosure relates to, for example, the following items. (Item 1) A hair dyeing accelerator containing a cationic polymer having a charge amount exceeding 0 meq / g at pH 7.0. (Item 2) The cationic polymer contains, as a monomer unit, a monomer unit containing at least one amine, and the monomer unit has the amine in the main chain or the cyclic part, or has it in the side chain so as to be located within 3 atomic lengths from the main chain. The hair dyeing accelerator according to Item 1. (Item 3) The number average molecular weight [g / mol] of the cationic polymer is 1000 or more and 5000000 or less. The hair dyeing accelerator according to Item 1 or 2. (Item 4) The hair dyeing accelerator according to any one of items 1 to 3, wherein the cationic polymer contains at least one selected from the group consisting of poly[oxyethylene(dimethylimino)propyl(dimethylimino)ethylene], ε-poly-L-lysine, and polyquaternium-2, polyquaternium-6, polyquaternium-22, and polyquaternium-72. (Item 5) The hair dyeing accelerator according to any one of items 1 to 4, wherein the cationic polymer contains poly[oxyethylene(dimethylimino)propyl(dimethylimino)ethylene]. (Item 6) The hair dyeing accelerator according to any one of items 1 to 5, for promoting hair dyeing with 5,6-dihydroxyindoles, 5,6-dihydroxyindolines, or salts thereof. (Item 7) The hair dyeing accelerator according to item 6, wherein the 5,6-dihydroxyindoles, 5,6-dihydroxyindolines, or salts thereof are 5,6-dihydroxyindole or salts thereof. (Item 8) A hair dyeing promotion method including contacting human hair with a cationic polymer. (Item 9) A hair dyeing method including contacting human hair with a cationic polymer and contacting human hair with 5,6-dihydroxyindoles, 5,6-dihydroxyindolines, or salts thereof.

Effect of the Invention

[0009] According to the present disclosure, a hair dyeing accelerator for human hair is provided. Such a hair dyeing accelerator for human hair can enhance the hair dyeing property of a hair dyeing composition.

Brief Description of the Drawings

[0010] [Figure 1] It is a figure showing a photograph under an indoor lamp of hair dyed with a hair dyeing composition containing DHI when pretreatment with a hair dyeing accelerator was not performed (Control) or when pretreatment was performed with a hair dyeing accelerator containing α-PL, ε-PL, or PA-1 in Test Example 1. [Figure 2] This figure shows the ΔE*ab values ​​of hair dyed with a DHI-containing hair dye composition in Test Example 1, either when no pretreatment with a hair dye accelerator was performed (Control) or when pretreatment was performed with a hair dye accelerator containing α-PL, ε-PL, or PA-1. [Figure 3] This figure shows the pH dependence of the surface potential of hair that was not treated with a hair dyeing stimulant in Test Example 3. [Figure 4] This figure shows the surface potential at pH 10.0 for hair that was not treated with a hair dyeing accelerator (Control) or hair that was treated with a hair dyeing accelerator containing α-PL, ε-PL, or PA-1 in Test Example 3. [Figure 5] This figure shows the fluorescence image and fluorescence intensity of hair labeled with the cationic fluorescent dye rhodamine 6G in Test Example 4, either after no pretreatment with a hair dyeing accelerator (Control) or after pretreatment with a hair dyeing accelerator containing α-PL, ε-PL, or PA-1. [Figure 6] This figure shows the fluorescence images and fluorescence intensity of hair 10 seconds, 5 minutes, 10 minutes, and 20 minutes after dropping the rhodamine 6G aqueous solution into the hair in Test Example 5. [Modes for carrying out the invention]

[0011] The following describes the forms for implementing this disclosure, but this disclosure is not limited to the following embodiments.

[0012] In this disclosure, "C m-n The notation "alkyl" (where m and n are positive integers) indicates an alkyl group with m or more carbon atoms and n or less carbon atoms. For example, C 1-5Examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, and 2,2-dimethylpropyl, which have 1 to 5 carbon atoms. 1-3 Examples of alkyl groups include methyl, ethyl, n-propyl, and isopropyl alkyl groups, which have 1 to 3 carbon atoms.

[0013] In this disclosure, the expression that a molecule or functional group has a positive charge means that, under certain conditions, 90% or more of that molecule or functional group will have a positive charge probabilistically. In this disclosure, the expression that a molecule or functional group has a negative charge means that, under certain conditions, 90% or more of that molecule or functional group will have a negative charge probabilistically. In this disclosure, the expression that a molecule or functional group does not have a negative charge means that, under certain conditions, the proportion of that molecule or functional group that has a negative charge is probabilistically less than 90%.

[0014] The hair dyeing accelerant of this embodiment is a hair dyeing accelerant for human hair that contains a cationic polymer with a charge of more than 0 meq / g at pH 7.0. The hair dyeing accelerant according to this embodiment may contain one or more cationic polymers.

[0015] A cationic polymer is a polymer that has at least one positive charge under conditions comparable to those on the surface of hair, with a charge at least greater than 0 meq / g at pH 7.0. When a hair dye accelerator contains a cationic polymer, the dyeability of hair that comes into contact with the dye accelerator is improved. For example, hair that comes into contact with a hair dye accelerator tends to have its surface charge shift from negative to positive, so if the dye contained in the subsequent hair dyeing composition is a negatively charged dye, the repulsion between negative charges can be suppressed, thereby improving the dyeability.

[0016] In one embodiment, the cationic polymer has a charge at pH 7.0 that is at least greater than 0 meq / g, and may be 1.0 meq / g or more, 2.0 meq / g or more, 3.0 meq / g or more, 4.0 meq / g or more, 5.0 meq / g or more, 6.0 meq / g or more, 6.5 meq / g or more, or 6.8 meq / g or more, and may be 20 meq / g or less, 15 meq / g or less, 10 meq / g or less, or 8.0 meq / g or less. When the charge of the cationic polymer in one embodiment at pH 7.0 satisfies the above requirements, the polymer becomes positively charged under neutral to weakly acidic conditions, which is the pH of hair under physiological conditions. This makes it easier for the charge on the surface of hair in contact with the hair dye accelerator to shift from negative to positive, thereby suppressing, for example, the repulsion between negative charges and thus improving the dyeability of the negatively charged dye.

[0017] In one embodiment, the cationic polymer may have a charge at pH 10.0 that is greater than 0 meq / g, and may be 1.0 meq / g or more, 2.0 meq / g or more, 3.0 meq / g or more, 4.0 meq / g or more, 5.0 meq / g or more, 6.0 meq / g or more, 6.5 meq / g or more, or 6.8 meq / g or more, and may be 20 meq / g or less, 15 meq / g or less, 10 meq / g or less, or 8.0 meq / g or less. If the charge of the cationic polymer according to one embodiment at pH 10.0 satisfies the above requirements, the polymer becomes positively charged in the pH range in which dyes that develop color under basic conditions, such as 5,6-dihydroxyindoles, 5,6-dihydroxyindolines, or their salts described later, develop color. As a result, when dyeing with pigments using such dyes, the charge on the surface of the hair that comes into contact with the hair dye accelerator tends to shift from negative to positive. This suppresses, for example, the repulsion between negative charges, making it easier for the dyes contained in the hair dye composition to adhere to the hair, and thus improving the dyeing performance of the negatively charged dyes.

[0018] A cationic polymer according to one embodiment does not need to contain a functional group having a negative charge at pH 7.0 within its molecule. A cationic polymer according to a preferred embodiment does not need to contain a functional group having a negative charge at pH 10.0 within its molecule. When a cationic polymer satisfies the above, the application of a hair growth stimulant to hair makes it easier to neutralize the negative charge on the hair surface, thereby improving the dyeability of hair with negatively charged dyes.

[0019] A cationic polymer according to one embodiment may contain at least one amine in its molecule, for example, at least one quaternary amine, tertiary amine, secondary amine, or primary amine in its molecule, or at least one quaternary amine, tertiary amine, or secondary amine in its molecule. A cationic polymer according to one embodiment may contain cationic monomer units. Because such cationic polymers tend to become positively charged on the hair surface, applying a hair growth stimulant to the hair easily cancels out the negative charge on the hair surface, thereby improving the dyeability of negatively charged dyes. Examples of such cationic polymers include poly[oxyethylene(dimethylimino)propyl(dimethylimino)ethylene] (hereinafter also referred to as "PA-1"), ε-poly-L-lysine (hereinafter also referred to as "ε-PL"), and the polyquaternium series, polyquaternium-2 (hereinafter referred to as "PQ-2"). Examples include polyquaternium-6, polyquaternium-22, polyquaternium-72, polyquaternium-4, polyquaternium-7, polyquaternium-10, polyquaternium-11, polyquaternium-39, polyquaternium-51, polyquaternium-55, polyquaternium-64, polyquaternium-4, polyquaternium-7, polyquaternium-11, and polyethyleneimine. That is, the cationic polymer according to one embodiment may include, for example, at least one selected from the group consisting of PA-1, ε-PL, and PQ-2, or at least one selected from the group consisting of these. The structures of PA-1, ε-PL, and PQ-2 are shown below. In the following structural formulas, n represents a natural number, for example, a natural number such that the number-average molecular weight of the cationic polymer is within a predetermined molecular weight range. Furthermore, in the following structural formulas, * indicates a terminal group of the polymer, for example, independently representing a hydrogen atom, or a monovalent group formed by adding one hydrogen atom to a divalent group that is part or all of the repeating unit of the polymer. [ka] [ka] [ka]

[0020] The cationic monomer unit contains an amine, which in one embodiment may contain a quaternary amine, a tertiary amine, or a secondary amine; in a preferred embodiment, it may contain a quaternary amine or a tertiary amine; and in a more preferred embodiment, it may contain a quaternary amine. The cationic monomer unit contains at least one amine, which in a preferred embodiment may contain two or more amines. The amine contained in the cationic monomer unit may in one embodiment be an amine that is positively charged at pH 7.0; and in a preferred embodiment, it may be an amine that is positively charged at pH 10.0.

[0021] The cationic monomer unit may be linear, cyclic, or have both linear and cyclic portions, and may be linear, for example. In these cases, the linear structure may be straight or branched. For example, the cationic monomer unit may be saturated or unsaturated, and in one embodiment, the carbon chain contained therein may be a saturated hydrocarbon group.

[0022] In one embodiment, the cationic monomer unit may have an amine in the main chain or cyclic portion. In this case, the charged state of the amine is less susceptible to the influence of the surrounding environment, which tends to enhance the hair dyeing effect of the hair dyeing accelerator. In another embodiment, the cationic monomer unit may have an amine in the side chain. In this case, it is preferable that the amine is located at a length of 10 atoms or less, 5 atoms or less, 3 atoms or less, or 2 atoms or less from the main chain. Note that atomic length refers to the number of atoms other than hydrogen atoms that pass from the root atom having the side chain in the main chain to the nitrogen atom of the amine, and the nitrogen atom that is reached is also included in the number.

[0023] A cationic polymer may contain one or more cationic monomer units. When a cationic polymer contains cationic monomer units, the content of cationic monomer units in the cationic polymer may be, for example, 10% by mass or more, 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, or 100% by mass, based on the mass of the cationic polymer, and may also be 100% by mass or less, 95% by mass or less, 85% by mass or less, 75% by mass or less, 65% by mass or less, 55% by mass or less, or 45% by mass or less. In one embodiment, the content of cationic monomer units in the cationic polymer may be 100% by mass. That is, in one embodiment, the cationic polymer may be a polymer composed of cationic monomer units.

[0024] A cationic polymer according to one embodiment may be a polymer whose three-dimensional structure at pH 7.0 is not a random coil structure, for example, a polymer whose three-dimensional structure at pH 7.0 is a sheet structure. A preferred cationic polymer according to one embodiment may be a polymer whose three-dimensional structure at pH 10.0 is not a random coil structure, for example, a polymer whose three-dimensional structure at pH 10.0 is a sheet structure. These three-dimensional structures may be the three-dimensional structures in aqueous solution. An example of a polymer that exists in a sheet structure at pH 7.0 and pH 10.0 is ε-PL.

[0025] A cationic polymer according to one preferred embodiment may contain at least one quaternary amine in its molecule, and the cationic monomer unit may contain a quaternary amine. A cationic polymer according to one more preferred embodiment has the following structural formula in its molecule: [ka] [In the formula, R a and R b Each is independently C 1-5 It represents an alkyl group, and in one embodiment, C 1-3 It exhibits alkyl properties, and in a specific embodiment, it exhibits methyl properties. It may contain at least one structure represented by, and the cationic monomer unit may contain the structure represented above. The cationic polymer according to a more preferred embodiment has the following general formula: [Chemical formula] [wherein, R a 、R b 、R c and R d each independently represents C 1-5 alkyl, in one embodiment represents C 1-3 alkyl, and in a specific embodiment represents methyl, L 1 and L 2 each independently represents a linker that is neither positively nor negatively charged at both pH 7.0 and pH 10.0, n represents a natural number, and in one embodiment represents a natural number such that the number average molecular weight of the cationic polymer falls within a predetermined molecular weight range, * represents the end group of the polymer, and for example, each independently represents a hydrogen atom or a monovalent group obtained by adding one hydrogen atom to a divalent group that is part of or the whole of the repeating unit of the polymer.] It may be represented by. Since such a cationic polymer is likely to be positively charged on the hair surface, application of the hair dye accelerator to the hair easily cancels the negative charge on the hair surface, thereby easily improving the hair dyeing property by the negatively charged dye.

[0026] The cationic polymer according to an even more preferred embodiment may contain at least one selected from the group consisting of PA-1, poly[oxyethylene(dimethylimino)ethylene(dimethylimino)ethylene], polyquaternium-2, polyquaternium-6, polyquaternium-22, and polyquaternium-72, may be at least one selected from the group consisting of these, may contain PA-1 and / or PQ-2, and may be PA-1 and / or PQ-2. The cationic polymer according to an even more and more preferred embodiment may contain PA-1 and may be PA-1.

[0027] The number-average molecular weight [g / mol] of the cationic polymer according to one embodiment may be, for example, 1000 or more, 5000 or more, 10000 or more, 30000 or more, 40000 or more, or 50000 or more, and may be 5000000 or less, 3000000 or less, 1000000 or less, 500000 or less, 300000 or less, or 100000 or less.

[0028] The content of the cationic polymer in the hair dyeing accelerant of this embodiment may be, for example, 0.0001% by mass, 0.001% by mass or more, 0.01% by mass or more, 0.03% by mass or more, 0.10% by mass or more, or 0.30% by mass or more, based on the total amount of the hair dyeing accelerant, and may also be 10.0% by mass or less, 5.00% by mass or less, 3.00% by mass or less, 2.50% by mass or less, 2.00% by mass or less, 1.50% by mass or less, or 1.00% by mass or less.

[0029] The hair dyeing accelerant of this embodiment may further contain water. The water content may be, for example, 10.0% by mass or more, 20.0% by mass or more, 30.0% by mass or more, 40.0% by mass or more, 50.0% by mass or more, 60.0% by mass or more, 70.0% by mass or more, or 80.0% by mass or more, based on the total amount of the hair dyeing accelerant, and may also be 99.9% by mass or less, 95.0% by mass or less, 85.0% by mass or less, 75.0% by mass or less, or 50.0% by mass or less.

[0030] The pH of the hair dyeing accelerator in this embodiment may be, for example, 4.0 or higher, 4.5 or higher, or 5.0 or higher, and may also be 7.0 or lower, 6.5 or lower, or 6.0 or lower.

[0031] The viscosity of the hair dyeing accelerator in this embodiment may be, for example, 100 to 10,000 mPa·s, 300 to 8,000 mPa·s, or 500 to 6,000 mPa·s. Viscosity (25°C) refers to the viscosity measured using a single-cylindrical rotational viscometer (Brookfield type viscometer) in accordance with the viscosity measurement method described in the general test methods of the 17th edition of the Japanese Pharmacopoeia. Specifically, it refers to the value measured using TV-10M (manufactured by Toki Sangyo Co., Ltd.), and the selection of conditions such as rotor and rotational speed shall be in accordance with the instruction manual of this machine, and the viscosity at 25°C shall be measured.

[0032] The following is a description of a single-cylinder rotational viscometer. A single-cylinder rotational viscometer is a viscometer that measures the torque when a cylinder in a liquid is rotated at a constant angular velocity. The viscosity η of the liquid is calculated by the following formula after experimentally determining the apparatus constant KB using a viscometer calibration standard solution. η = KB × T / ω η: Viscosity of liquid (mPa·s) KB: Equipment constant (rad / cm 3 ) ω: Angular velocity (rad / s) T: Torque acting on the cylindrical surface (10 -7 N·m)

[0033] The hair dyeing accelerator according to this embodiment is an agent for improving the dyeability of human hair by the dye contained in the hair dyeing composition. In this disclosure, improved dyeability means that the color of the hair after dyeing is enhanced by the color derived from the dye.

[0034] A hair dyeing accelerator according to one aspect of this embodiment may be a hair dyeing accelerator for enhancing the dyeability of negatively charged dyes. While we do not wish to be bound by any theory, hair that comes into contact with a cationic polymer tends to have its negative charge on its surface canceled out, thus increasing its dyeability with negatively charged dyes.

[0035] A hair dyeing accelerator according to one aspect of this embodiment may be a hair dyeing accelerator for enhancing the dyeability of air-oxidized dyes. Air-oxidized dyes are dyes in which hair is dyed by the development of a colorless or nearly colored precursor after it is applied to the hair. Such dyes need to penetrate and fix into the hair, and according to a hair dyeing accelerator according to one aspect of this disclosure, the penetration of the dye precursor into the hair can be increased, thereby improving the dyeability of the dye.

[0036] A hair dyeing accelerator according to a preferred embodiment of this model may be a hair dyeing accelerator for promoting hair dyeing with 5,6-dihydroxyindole compounds, 5,6-dihydroxyindoline compounds, or their salts. 5,6-dihydroxyindole compounds, 5,6-dihydroxyindoline compounds, or their salts are air-oxidation type dyes that develop color under basic conditions of pH 10.0, and are negatively charged under such basic conditions. Therefore, although we do not wish to be bound by any theory, hair that comes into contact with such a cationic polymer at the pH at which 5,6-dihydroxyindole compounds, 5,6-dihydroxyindoline compounds, or their salts develop color will have its negative charge on the surface canceled out, making it easier for 5,6-dihydroxyindole compounds, 5,6-dihydroxyindoline compounds, or their salts to penetrate and fix, and thus the dyeability with 5,6-dihydroxyindole compounds, 5,6-dihydroxyindoline compounds, or their salts to be enhanced. More specifically, since the pKa of 5,6-dihydroxyindole is 9.8, under alkaline conditions of pH 10 or higher, which are suitable for the color development of DHI compounds, the charge becomes negative. However, since the isoelectric point of hair is around pH 5, the charge becomes negative under alkaline conditions, and repulsion occurs between negative charges. This can make it difficult for the dye to adhere to the hair, potentially leading to a decrease in dyeability. However, when hair comes into contact with a cationic polymer, the charge becomes positive, which suppresses such charge repulsion and improves dyeability.

[0037] The 5,6-dihydroxyindole derivatives, 5,6-dihydroxyindoline derivatives, or salts thereof relating to this disclosure will be described in more detail. In this disclosure, 5,6-dihydroxyindole is also referred to as "DHI," and 5,6-dihydroxyindole derivatives and 5,6-dihydroxyindoline derivatives are also referred to as "DHI derivatives." In this disclosure, 5,6-dihydroxyindole derivatives may include 5,6-dihydroxyindole and its derivatives, and 5,6-dihydroxyindoline derivatives may include 5,6-dihydroxyindoline and its derivatives.

[0038] DHI compounds are melanin precursors that polymerize to form melanin when oxidized. Melanin is one of the pigments that causes human hair to appear black, whereas unoxidized DHI compounds or their salts are colorless or nearly colorless. In this disclosure, the process by which DHI compounds or their salts polymerize upon air oxidation after application to hair, forming a melanin-like pigment and developing color, is referred to as hair dyeing with DHI compounds or their salts. Pigments that develop color through such oxidation are sometimes called air-oxidized pigments.

[0039] The DHI compounds relating to this disclosure may be, for example, compounds represented by the following formula (I). [ka]

[0040] In equation (I), the following combination is observed: [ka] This indicates whether the bond is a single bond or a double bond. When the bond shown above is a single bond, the compound represented by formula (I) corresponds to 5,6-dihydroxyindolines. When the bond shown above is a double bond, the compound represented by formula (I) corresponds to 5,6-dihydroxyindoles. In one embodiment, the bond shown above may be a double bond.

[0041] In equation (I), R 1 is a hydrogen atom or C 1-5 It is an alkyl group, and in one embodiment, a hydrogen atom or C 1-3 It may be an alkyl group, and in a preferred embodiment, it may be a hydrogen atom.

[0042] In equation (I), R 2 is a hydrogen atom, carboxyl, or C 1-5 It is an alkoxycarbonyl, which in one embodiment may be a hydrogen atom or a carboxyl atom, and in a preferred embodiment may be a hydrogen atom.

[0043] In one embodiment, the DHIs relating to this disclosure may be 5,6-dihydroxyindole, 5,6-dihydroxyindoline, or 5,6-dihydroxyindole-2carboxylic acid, and in a preferred embodiment, they may be 5,6-dihydroxyindole or 5,6-dihydroxyindoline. In formula (I), 5,6-dihydroxyindole is R 1 is a hydrogen atom, and R 2 R is a hydrogen atom, and the bond represented above is a double bond. In formula (I), R is a hydrogen atom in 5,6-dihydroxyindole. 1 is a hydrogen atom, and R 2 R is a hydrogen atom, and the bond represented above is a single bond. 5,6-Dihydroxyindole-2carboxylic acid is a compound in formula (I) where R 1 is a hydrogen atom, and R 2 The compound is one in which carboxyl is present and the bond represented above is a double bond.

[0044] Salts of DHI compounds may be pharmaceutically or cosmetically acceptable salts. Salts of DHI compounds may be salts with anions, salts with cations, or salts with both anions and cations.

[0045] The counteranion in the salts of DHI may be, for example, a monovalent anion. In one embodiment, the counteranion in the salts of DHI may be a halide ion, a hydroxide ion, an acetate ion, or a lactate ion, and in a preferred embodiment, it may be a halide ion.

[0046] The countercation in a salt of DHI may be, for example, a monovalent cation. In one embodiment, the countercation in a salt of DHI may be an alkali metal ion or an ammonium ion, and in a preferred embodiment, it may be a sodium ion or a potassium ion.

[0047] Component (A) in a more preferred embodiment may be at least one selected from the group consisting of 5,6-dihydroxyindole and 5,6-dihydroxyindole-2carboxylic acid and salts thereof with halide ions. Component (A) in the most preferred embodiment may be 5,6-dihydroxyindole or a bromate salt of 5,6-dihydroxyindole.

[0048] When a hair dye accelerator is intended to promote hair dyeing with DHI compounds or their salts, the improvement of dyeability by the hair dye accelerator means that the color of the dyed hair becomes closer to black (darker) after application of the hair dye accelerator. As a detailed example, in this disclosure, the improvement of dyeability by DHI compounds or their salts by the hair dye accelerator means that the color difference ΔE*ab in a bundle of gray hair dyed with DHI compounds or their salts after using the hair dye accelerator is, for example, 0.30 or greater, 0.60 or greater, 0.90 or greater, 1.20 or greater, or 1.50 or greater compared to when the hair dye accelerator is not used. In the above, the color difference ΔE*ab is a value calculated by the following formula based on the lightness (L*), hue (a*), and saturation (b*) measured on the surface of the dyed hair using a colorimeter. ΔE*ab=[(ΔL*) 2 +(Δa*) 2 +(Δb*) 2 ] 1 / 2

[0049] If the hair dyeing accelerator is for accelerating hair dyeing with DHI compounds or their salts, the hair dyeing accelerator according to one aspect of this embodiment may change the color of hair dyed with DHI compounds or their salts. For example, in this disclosure, a hair dyeing accelerator changing the color of DHI compounds or their salts means that, compared to the case where the hair dyeing accelerator is not used, the hue (a*) of a bundle of gray hair dyed with DHI compounds or their salts after using the hair dyeing accelerator is, for example, 0.30 or more, 0.35 or more, 0.40 or more, 0.45 or more, 0.50 or more, 0.55 or more, 0.60 or more, 0.65 or more, 0.70 or more, 0.75 or more, or 0.80 or more. In the above, the hue (a*) can be measured, for example, using a colorimeter. If a hair dyeing accelerator according to one aspect of this embodiment changes the color of hair dyed with DHI compounds or their salts, it can be expected that the hair dyeing accelerator according to one aspect of this embodiment can be applied to actively adjust the color of dyed hair and enhance its variations (so-called multi-coloring).

[0050] If the hair dyeing accelerator is intended to promote hair dyeing with DHI compounds or their salts, the hair dyeing accelerator according to one aspect of this embodiment may enhance the stability of the dyed state (fastness of the dye) in hair dyed with DHI compounds or their salts. The enhanced stability of the dyed state by the hair dyeing accelerator according to one aspect of this embodiment can be evaluated, for example, by suppressing the decrease in dyeability when the dyed hair is incubated in water containing a surfactant for a predetermined time (e.g., 10 minutes to 24 hours) or washed with a detergent containing a surfactant, by pre-treatment with the hair dyeing accelerator according to one aspect of this embodiment. As a detailed example, enhanced stability of the dyed state by the hair dyeing accelerator according to one aspect of this embodiment may mean, for example, that when dyed hair is immersed in a 1% sodium lauryl sulfate aqueous solution and incubated for 30 minutes, the ΔE*ab, based on the measurement value before incubation, is 5.00 or less, 2.50 or less, 2.30 or less, 2.10 or less, 1.90 or less, 1.70 or less, or 1.00 or less. When the stability of the dyed state is improved in hair dyed with DHI compounds or their salts, the frequency of dyeing required to maintain the dyed state decreases, thereby reducing the burden on the person whose hair is being dyed.

[0051] The hair dyeing stimulant of this embodiment is applied to the hair immediately before or at the same time as the application of the hair dyeing composition. The form of the hair dyeing stimulant of this embodiment is not particularly limited as long as it does not deviate from the purpose of improving the dyeability of the hair by the dye, and may further contain other appropriate components depending on the form. The hair dyeing stimulant of this embodiment may be, for example, a formulation intended solely for the purpose of accelerating hair dyeing (i.e., a pre-treatment agent applied before the application of the hair dyeing composition), and may be in the form of a shampoo, hair mist, hair oil, hair milk, treatment introductory liquid, or conditioner, in which case the hair dyeing stimulant of this embodiment may be applied to the hair immediately before the application of the hair dyeing composition. The hair dyeing stimulant according to one aspect of this embodiment may be in the form of a shampoo. The hair dyeing stimulant of this embodiment may be, for example, a liquid or a semi-solid. The hair dyeing stimulant of this embodiment may be applied as a liquid, cream, emulsion, gel, paste, mousse, or aerosol, and in one aspect it may be applied as a liquid, cream, emulsion, gel, or paste.

[0052] If the hair dyeing stimulant of this embodiment is a formulation intended solely for promoting hair dyeing, the hair dyeing stimulant may also contain at least one other component selected from the group consisting of, for example, pH adjusters, buffers, thickeners, surfactants, preservatives, fragrances, and colorants. If the hair dyeing stimulant of this embodiment is a formulation intended solely for promoting hair dyeing, the application of the hair dyeing stimulant to the hair can be performed by first applying or spraying the hair dyeing stimulant onto the hair, maintaining that state for a predetermined time (for example, 1 to 30 minutes or 1 to 10 minutes), and then washing the hair, thereby achieving the effect of promoting hair dyeing.

[0053] When the hair dyeing stimulant of this embodiment is in the form of a shampoo, the hair dyeing stimulant may also contain at least one other component selected from the group consisting of, for example, surfactants, humectants, thickeners, emulsifying stabilizers, preservatives, fragrances, colorants, pH adjusters, and buffering agents. Examples of surfactants include cocamidopropyl betaine as an amphoteric surfactant, sodium lauroyl methylalanine and tetradecyl sulfonic acid as anionic surfactants, coconut oil fatty acid diethanolamide as a nonionic surfactant, and glycerin as a humectant. When the hair dyeing stimulant of this embodiment is in the form of a shampoo, the application of the hair dyeing stimulant to the hair can be carried out in the same manner as with ordinary shampoo, thereby producing the effect of promoting hair dyeing.

[0054] If the hair dyeing stimulant of this embodiment is in the form of a conditioner, the hair dyeing stimulant may also contain, as other components, at least one selected from the group consisting of, for example, cationic surfactants, silicones, oily components, amino acids, peptides, vitamins, humectants, thickeners, emulsifiers, emulsifying stabilizers, preservatives, fragrances, colorants, pH adjusters, and buffering agents. If the hair dyeing stimulant of this embodiment is in the form of a conditioner, the application of the hair dyeing stimulant to the hair can be carried out in the same manner as for a normal conditioner, thereby producing the effect of promoting hair dyeing.

[0055] The amount of the hair dyeing stimulant according to one aspect of this embodiment applied to hair may be, as the amount of cationic polymer, for example, 0.10 mg or more, 0.50 mg or more and 1.00 mg or more, 5.00 mg or more, 10 mg or more, 50 mg or more, or 100 mg or more per 1000 mg of hair, and may also be 10000 mg or less, 1000 mg or less, 500 mg or less, 300 mg or less, 100 mg or less, or 30.0 mg or less.

[0056] The hair dyeing accelerator according to one aspect of this embodiment does not need to contain an antioxidant. If the hair dyeing accelerator according to one aspect does not contain an antioxidant, the dye becomes more susceptible to oxidation, especially if the dye contained in the hair dyeing composition is an air-oxidation type dye, thus improving the hair dyeing performance.

[0057] As described above, a hair dyeing accelerator according to a preferred embodiment of this embodiment may be a hair dyeing accelerator for promoting hair dyeing with DHI compounds or their salts. Next, we will describe a human hair dyeing composition containing DHI compounds or their salts, which is the target of hair dyeing promotion by the hair dyeing accelerator when the hair dyeing accelerator is for promoting hair dyeing with DHI compounds or their salts. That is, a hair dyeing accelerator according to a preferred embodiment of this embodiment may be for promoting the dyeing properties of the human hair dyeing composition described below.

[0058] The human hair dyeing composition contains (A) 5,6-dihydroxyindole compounds, 5,6-dihydroxyindoline compounds, or salts thereof. The human hair dyeing composition may further contain (A) 5,6-dihydroxyindole compounds, 5,6-dihydroxyindoline compounds, or salts thereof, and (B) basic dyes and / or (C) HC dyes. Hereafter, (A) 5,6-dihydroxyindole compounds, 5,6-dihydroxyindoline compounds, or salts thereof will also be referred to as "component (A)", (B) basic dyes will also be referred to as "component (B)", and (C) HC dyes will also be referred to as "component (C)".

[0059] The content of component (A) in the human hair dyeing composition may be, for example, 0.001% by mass or more, 0.01% by mass or more, 0.03% by mass or more, 0.05% by mass or more, 0.10% by mass or more, or 0.15% by mass or more, based on the total amount of the composition, and may also be 3.00% by mass or less, 1.00% by mass or less, 0.50% by mass or less, 0.40% by mass or less, or 0.30% by mass or less.

[0060] The content of the air-oxidizing dye containing component (A) in the human hair dyeing composition may be, for example, 0.001% by mass or more, 0.01% by mass or more, 0.03% by mass or more, 0.05% by mass or more, 0.10% by mass or more, 0.15% by mass or more, based on the total amount of the composition, and may be 3.00% by mass or less, 1.00% by mass or less, 0.50% by mass or less, 0.40% by mass or less, or 0.30% by mass or less. Examples of air-oxidizing dyes other than component (A) that may be included in the human hair dyeing composition include indigo (e.g., derived from Indigofera tinctoria leaves), henna, and paraphenylenediamine.

[0061] (B) Component is a basic dye. In Japan, basic dyes became permissible to be included in hair dyeing compositions following the amendment of the Pharmaceutical Affairs Law in 2001. Basic dyes are a type of direct dye.

[0062] Basic dyes are those that can be used or are capable of being used as dyes in hair dyeing compositions for human hair. For example, basic dyes may be dyes that have been assigned the cosmetic labeling name "Basic <color><number>" by the Japan Cosmetic Industry Association (JCIA). Also, for example, basic dyes may be those that have been assigned the cosmetic labeling name "Basic <color><number>" by the Personal Care Products Council (PCPC). <color> <number>The dye may be one to which the INCI name " is assigned. The color of the basic dye may be, for example, blue, red, yellow, purple, brown, orange, or green.

[0063] (B) Component may consist of one basic dye, or two or more basic dyes. Basic dyes include, for example, Basic Orange 1, Basic Orange 31, Basic Violet 1, Basic Violet 14, Basic Violet 16, Basic Violet 2, Basic Violet 3, Basic Violet 4, Basic Green 1, Basic Green 4, Basic Brown 16, Basic Brown 17, Basic Brown 4, Basic Red 2, Basic Red 22, Basic Red 46, Basic Red 51, Basic Red 76, and Basic Blue 124. 124) It may be at least one selected from the group consisting of Basic Blue 26, Basic Blue 3, Basic Blue 47, Basic Blue 7, Basic Blue 75, Basic Blue 9, Basic Blue 99, Basic Yellow 40, Basic Yellow 57, and Basic Yellow 87.

[0064] The content of component (B) in the human hair dyeing composition may be, for example, 0.0001% by mass or more, 0.001% by mass or more, 0.01% by mass or more, 0.05% by mass or more, 0.20% by mass or more, or 0.30% by mass or more, based on the total amount of the composition, and may also be 5.00% by mass or less, 2.00% by mass or less, 1.00% by mass or less, or 0.50% by mass or less.

[0065] In a human hair dyeing composition, the content of component (B) relative to the content of component (A) may be, as a ratio by mass, for example, 0.00001 times or more, 0.0001 times or more, 0.001 times or more, 0.01 times or more, 0.1 times or more, or 1.00 times or more, and may also be 5000 times or less, 1000 times or less, 100 times or less, 60.0 times or less, 30.0 times or less, 10.0 times or less, 5.00 times or less, or 3.00 times or less.

[0066] (C) Component is an HC dye. In Japan, HC dyes became permissible to be included in hair dyeing compositions following the amendment of the Pharmaceutical Affairs Law in 2001. HC dyes are a type of direct dye.

[0067] HC dyes are those that may or may be used as dyes in hair dyeing compositions for human hair. For example, an HC dye may be a dye that has been assigned the cosmetic labeling name "HC<color><number>" by the Japan Cosmetic Industry Association (JCIA). Also, for example, an HC dye may be one that has been assigned the cosmetic labeling name "HC" by the Personal Care Products Council (PCPC). <color>No. <number>The dye may be assigned the INCI name ". The color of the HC dye may be, for example, blue, red, yellow, purple, brown, orange, or green.

[0068] (C) component may use one type of HC dye, or may use two or more types of HC dyes. The HC dye may be at least one selected from the group consisting of, for example, HC Orange No.1, HC Orange No.2, HC Orange No.6, HC Orange No.7, HC Violet No.1, HC Violet No.2, HC Violet No.3, HC Violet No.4, HC Brown No.3, HC Brown No.4, HC Red No.1, HC Red No.10, HC Red No.11, HC Red No.13, HC Red No.17, HC Red No.18, HC Red No.19, HC Red No.20, HC Red No.21, HC Red No.3, HC Red No.7, HC Blue No.11, HC Blue No.12, HC Blue No.14, HC Blue No.15, HC Blue No.16, HC Blue No.18, HC Blue No.19, HC Blue No.2, HC Blue No.20, HC Blue No.8, HC Yellow No.11, HC Yellow No.13, HC Yellow No.16, HC Yellow No.17, HC Yellow No.18, HC Yellow No.2, HC Yellow No.4, HC Yellow No.5, HC Yellow No.7, and HC Yellow No.9.

[0069] The content of component (C) in the human hair dyeing composition may be, for example, 0.001% by mass or more, 0.01% by mass or more, 0.05% by mass or more, or 0.20% by mass or more, based on the total amount of the composition, and may also be 10.0% by mass or less, 5.00% by mass or less, 2.00% by mass or less, or 1.00% by mass or less.

[0070] In a human hair dyeing composition, the ratio of the content of component (C) to the content of component (A) may be, for example, 0.0001 times or more, 0.001 times or more, 0.01 times or more, 0.01 times or more, 0.01 times or more, 0.30 times or more, 0.50 times or more, or 1.00 times or more as a ratio by mass, and may also be 10,000 times or less, 1,000 times or less, 100 times or less, 60.0 times or less, 30.0 times or less, 10.0 times or less, 5.00 times or less, or 3.00 times or less.

[0071] In a human hair dyeing composition, the content of component (C) relative to the content of component (B) may be, as a ratio of mass, for example, 0.00001 times or more, 0.0001 times or more, 0.001 times or more, 0.01 times or more, 0.05 times or more, 0.20 times or more, or 0.50 times or more, and may also be 100,000 times or less, 10,000 times or less, 1,000 times or less, 100 times or less, 40.0 times or less, 10.0 times or less, or 4.00 times or less.

[0072] In a human hair dyeing composition, the total content of component (B) and component (C) may be, for example, 0.001% by mass or more, 0.01% by mass or more, 0.10% by mass or more, 0.30% by mass or more, 0.45% by mass or more, or 0.5% by mass, based on the total amount of the composition, and may also be 30.0% by mass or less, 20.0% by mass or less, 10.0% by mass or less, 6.00% by mass or less, 2.00% by mass or less, or 1.50% by mass or less.

[0073] In a human hair dyeing composition, the total content of components (B) and (C) relative to the content of component (A) may be, as a mass ratio, for example, 0.0001 times or more, 0.001 times or more, 0.01 times or more, 0.1 times or more, 0.30 times or more, 0.50 times or more, 1.00 times or more, or 2.50 times or more, and may also be 1500 times or less, 1000 times or less, 100 times or less, 40.0 times or less, 10.0 times or less, or 5.00 times or less.

[0074] In a human hair dyeing composition, the content of the direct dye containing component (B) and component (C) may be, for example, 0.001% by mass or more, 0.01% by mass or more, 0.10% by mass or more, 0.30% by mass or more, 0.45% by mass or more, or 0.50% by mass, based on the total amount of the composition, and may also be 30.0% by mass or less, 20.0% by mass or less, 10.0% by mass or less, 6.00% by mass or less, 2.00% by mass or less, or 1.50% by mass or less.

[0075] In a human hair dyeing composition, the content of direct dyes containing components (B) and (C) relative to the content of air-oxidized dyes containing component (A) may be, as a mass ratio, for example, 0.0001 times or more, 0.001 times or more, 0.01 times or more, 0.1 times or more, 0.30 times or more, 0.50 times or more, 1.00 times or more, or 2.50 times or more, and may also be 1500 times or less, 1000 times or less, 100 times or less, 40.0 times or less, 10.0 times or less, or 5.00 times or less.

[0076] Examples of direct dyes other than components (B) and (C) that may be included in a human hair dyeing composition include nitro dyes, acid dyes, and disperse dyes. Examples of nitro dyes include 2-nitro-paraphenylenediamine, 2-amino-6-chloro-4-nitrophenol, 3-nitro-parahydroxyethylaminophenol, 4-nitro-orthophenylenediamine, 4-amino-3-nitrophenol, 4-hydroxypropylamino-3-nitrophenol, N,N-bis-(2-hydroxyethyl)-2-nitro-paraphenylenediamine, 4-nitro-o-phenylenediamine, 2-nitro-p-phenylenediamine, 2-amino-4-nitrophenol, 2-amino-5-nitrophenol, N,N'-bis(2-hydroxyethyl)-2-nitro-p-phenylenediamine, hydroxyethyl-2-nitro-p-toluidine, picramic acid, and picric acid. Acid dyes include Red No. 2, Red No. 3, Red No. 102, Red No. 104 (1), Red No. 105 (1), Red No. 106, Red No. 201, Red No. 227, Red No. 230 (1), Red No. 230 (2), Red No. 231, Red No. 232, Red No. 401, Red No. 502, Red No. 503, Red No. 504, Red No. 506, Yellow No. 4, Yellow No. 5, Yellow No. 202 (1), Yellow No. 202 (2), Yellow No. 203, Yellow No. 402, Yellow No. 403 (1), Yellow No. 406, Yellow No. 407, Orange No. 205, Orange No. 207 Examples of disperse dyes include Orange No. 402, Green No. 3, Green No. 204, Green No. 205, Green No. 401, Green No. 402, Purple No. 401, Blue No. 1, Blue No. 2, Blue No. 202, Blue No. 203, Blue No. 205, Brown No. 201, Black No. 401, Acid Blue 1, Acid Blue 3, Acid Blue 62, Acid Black 52, Acid Brown 13, Acid Green 50, Acid Orange 6, Acid Red 14, Acid Red 35, Acid Red 73, Acid Red 184, and Brilliant Black 1. Examples of disperse dyes include Disperse Black 9, Disperse Blue 1, Disperse Blue 3, Disperse Blue 7, Disperse Brown 4, Disperse Orange 3, Disperse Red 11, Disperse Red 15, Disperse Red 17, Disperse Purple 1, Disperse Purple 4, and Disperse Purple 15.

[0077] In one embodiment, the human hair dyeing composition may further contain, as component (D), at least one selected from the group consisting of ethanol and polyhydric alcohols.

[0078] (D) Component may be used alone or in combination of two or more. In one embodiment, component (D) may be a polyhydric alcohol. The polyhydric alcohol in component (D) may be at least one selected from the group consisting of alkylene glycols, glycerin, sugar alcohols and their oligomers. In one embodiment, the polyhydric alcohol is C 1-5 The alkyl group may be a compound in which at least two hydrogen atoms are substituted with hydroxyl groups. In another embodiment, the polyhydric alcohol may be at least one selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, hexylene glycol, glycerin, diglycerin, polyglycerin, xylitol, mannitol, galactite, sorbitol, pentaerythritol, and pentadiol. In a preferred embodiment, the polyhydric alcohol may be at least one selected from the group consisting of glycerin, dipropylene glycol, 1,2-butylene glycol, and 1,3-butylene glycol. In one embodiment, the human hair dyeing composition may not contain ethanol.

[0079] The polyhydric alcohol content in the human hair dyeing composition may be, for example, 0.01% by mass or more, 0.01% by mass or more, 0.10% by mass or more, 0.50% by mass or more, 2.00% by mass or more, or 5.00% by mass or more, based on the total amount of the composition, and may also be 30.0% by mass or less, 20.0% by mass or less, 15.0% by mass or less, 10.0% by mass or less, or 8.00% by mass or less.

[0080] The content of polyhydric alcohol relative to the content of component (A) in the human hair dyeing composition may be, for example, 0.001 times or more, 0.01 times or more, 0.1 times or more, 1.0 times or more, 5.0 times or more, 10 times or more, 15 times or more, or 20 times or more as a ratio by mass, and may also be 30,000 times or less, 10,000 times or less, 1,000 times or less, 100 times or less, 50 times or less, or 30 times or less.

[0081] The total content of polyhydric alcohols relative to the sum of the content of components (A), (B), and (C) in the human hair dyeing composition may be, for example, 0.0001 times or more, 0.001 times or more, 0.01 times or more, 0.1 times or more, 1.0 times or more, 3.0 times or more, or 4.0 times or more as a ratio by mass, and may also be 15,000 times or less, 10,000 times or less, 1,000 times or less, 100 times or less, or 10 times or less.

[0082] The ethanol content in the human hair dyeing composition may be, for example, 0.001% by mass or more, 0.01% by mass or more, 0.10% by mass or more, 0.50% by mass or more, 1.0% by mass or more, or 2.0% by mass or more, based on the total amount of the composition, and may also be 10% by mass or less, 5.0% by mass or less, or 3.0% by mass or less.

[0083] The ratio of ethanol content to the content of component (A) in the human hair dyeing composition may be, for example, 0.0001 times or more, 0.001 times or more, 0.01 times or more, 0.1 times or more, 1.0 times or more, 3.0 times or more, or 5.0 times or more by mass, and may also be 10,000 times or less, 1,000 times or less, 100 times or less, 50 times or less, 30 times or less, or 10 times or less.

[0084] The amount of ethanol relative to the total amount of components (A), (B), and (C) in the human hair dyeing composition may be, for example, 0.0001 times or more, 0.001 times or more, 0.01 times or more, 0.1 times or more, 0.3 times or more, or 0.5 times or more as a mass ratio, and may also be 5000 times or less, 1000 times or less, 100 times or less, 10 times or less, 5.0 times or less, or 3.0 times or less.

[0085] The ethanol content relative to polyhydric alcohols in a human hair dyeing composition may be, for example, 0.00001 times or more, 0.0001 times or more, 0.001 times or more, 0.01 times or more, 0.01 times or more, 0.1 times or more, or 0.2 times or more as a mass ratio, and may also be 10,000 times or less, 1,000 times or less, 100 times or less, 50 times or less, 10 times or less, 5.0 times or less, or 1.0 times or less.

[0086] The total content of component (D) in the human hair dyeing composition may be, for example, 0.01% by mass or more, 0.10% by mass or more, 0.50% by mass or more, 2.00% by mass or more, or 5.00% by mass or more, based on the total amount of the composition, and may also be 30.0% by mass or less, 20.0% by mass or less, 15.0% by mass or less, 10.0% by mass or less, or 8.00% by mass or less.

[0087] The total content of component (D) relative to the content of component (A) in the human hair dyeing composition may be, for example, 0.001 times or more, 0.01 times or more, 0.1 times or more, 1.0 times or more, 5.0 times or more, 10 times or more, 15 times or more, or 20 times or more as a ratio by mass, and may also be 30,000 times or less, 10,000 times or less, 1,000 times or less, 100 times or less, 50 times or less, or 30 times or less.

[0088] In a human hair dyeing composition, the total content of component (D) relative to the total content of components (A), (B), and (C) may be, as a ratio by mass, for example, 0.0001 times or more, 0.001 times or more, 0.01 times or more, 0.1 times or more, 1.0 times or more, 3.0 times or more, or 5.0 times or more, and may be 15,000 times or less, 10,000 times or less, 1,000 times or less, 100 times or less, or 10 times or less.

[0089] In one embodiment, the human hair dyeing composition may further contain an antioxidant as component (E).

[0090] Component (E) may be used alone or in combination of two or more types. Component (E) may be at least one selected from the group consisting of, for example, ascorbic acid-based, sulfite-based, tocopherol-based, EDTA-based, sulfur-based, and L-cysteine-based antioxidants. Examples of ascorbic acid-based antioxidants include ascorbic acid and ascorbyl palmitate and their salts. Examples of sulfite-based antioxidants include sulfurous acid and pyrosulfite and their salts, such as sodium sulfite, sodium pyrosulfite, or sodium bisulfite. Examples of tocopherol-based antioxidants include tocopherol and tocopheryl acetate and their salts. Examples of EDTA-based antioxidants include ethylenediaminetetraacetic acid and its salts. Examples of sulfur-based antioxidants include sulfur dioxide and thioglycolic acid. Examples of L-cysteine-based antioxidants include L-cysteine ​​and N-acetyl-L-cysteine. Component (E) in one embodiment may include at least one selected from the group consisting of ascorbic acid, sulfite, and salts thereof, or it may be at least one selected from the group consisting of ascorbic acid, sulfite, and salts thereof.

[0091] The content of component (E) in the human hair dyeing composition may be, for example, 0.001% by mass or more, 0.01% by mass or more, 0.10% by mass or more, or 0.30% by mass or more, based on the total amount of the composition, and may also be 2.00% by mass or less, 1.00% by mass or less, or 0.60% by mass or less.

[0092] In one embodiment, the human hair dyeing composition may further contain a base as component (F). The base contained in the human hair dyeing composition is sometimes called an alkaline agent. Thus, in one embodiment, component (F) can also be said to be an alkaline agent, and for example, a component that is sometimes used as an alkaline agent can be used.

[0093] Component (F) may be an organic base and / or an inorganic base. Examples of organic bases include secondary, tertiary, or quaternary amines having at least one substituent selected from the group consisting of hydroxyalkyl, alkyl, and alkenyl, and ammonia. Examples of inorganic bases include alkali metal or alkaline earth metal carbonates, bicarbonates, or hydroxides. Component (F) in one embodiment may contain an alkanolamine, may be an alkanolamine, or may be a monoalkanolamine. The alkanolamine may be at least one selected from the group consisting of monoethanolamine, diethanolamine, triethanolamine, mono-n-propanolamine, di-n-propanolamine, tri-n-propanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, 2-amino-2-methylpropanol, and 2-aminobutanol. Component (F) in a preferred embodiment may be a monoethanolamine.

[0094] The content of component (F) in the human hair dyeing composition may be, for example, 0.01% by mass or more, 0.10% by mass or more, 0.35% by mass or more, 0.80% by mass or more, 1.00% by mass or more, or 2.00% by mass or more, based on the total amount of the composition, and may also be 12.0% by mass or less, 8.00% by mass or less, 5.00% by mass or less, or 4% or less.

[0095] In one embodiment, the human hair dyeing composition may further contain water as component (G). Water can be a solvent in the human hair dyeing composition. The water content in the human hair dyeing composition may be, for example, 10.0% by mass or more, 40.0% by mass or more, 60.0% by mass or more, or 70.0% by mass or more, and may be 95.0% by mass or less, 90.0% by mass or less, 85.0% by mass or less, or 82.0% by mass or less.

[0096] In one embodiment, the human hair dyeing composition may further contain additives as other components. The additives may be at least one additive selected from the group consisting of, for example, surfactants (emulsifiers), emulsifying stabilizers, polymers, preservatives, acids, chelating agents, buffering agents, texture enhancers, solubilizers, amino acids, vitamins, and fragrances. The additives may be those commonly used in hair dyeing compositions.

[0097] The surfactant may be at least one selected from the group consisting of nonionic surfactants, cationic surfactants, anionic surfactants, and amphoteric surfactants, and in one embodiment, it may be at least one selected from the group consisting of nonionic surfactants and cationic surfactants. As the surfactant, those commonly used in hair dyeing compositions can be used. Nonionic surfactants may be, for example, fatty acid amide ethanolamine, alkyl polyglycoside, ethoxylated triglycerides, ethoxylated aliphatic alcohols, ethoxylated fatty acid esters, or mixtures thereof, and examples include glyceryl stearate, cocamide MEA, polysorbate 80, laureth-7, ceteareth-20, and sorbitan monolaurate. Cationic surfactants may be surfactants having, for example, a chain-like hydrocarbon group with 12 to 22 carbon atoms and an ammonium group or a tertiary amino group, and examples include behentrimonium chloride, cetrimonium chloride, stearalkonium chloride, cetrimonium bromide, cetrimonium methosulfate, steartrimonium chloride, behentrimonium methosulfate, behenamidopropyltrimonium methosulfate, stearamidopropyltrimonium chloride, distearyldimonium chloride, stearamidopropyldimethylamine, behenamidopropyldimethylamine, and behenamidopropyldiethylamine. The surfactant content in the human hair dyeing composition may be, for example, 1.00% by mass or more and 10.0% by mass or 3.00% by mass or more and 8.00% by mass or less, based on the total amount of the composition.

[0098] As the emulsifying stabilizer, one that is commonly used in hair dyeing compositions can be used. The emulsifying stabilizer may be, for example, an alkanol, or a higher alkanol. In this disclosure, a higher alkanol means a monovalent alkanol having 12 to 22 carbon atoms, and examples include lauryl alcohol, cetanol, cetyl alcohol, stearyl alcohol, arachidyl alcohol, behenyl alcohol, myristyl alcohol, oleyl alcohol, cetostearyl alcohol, 2-decyltetradecanol, hexyldodecanol, isostearyl alcohol, octyldodecanol, etc., and in one embodiment, it may be at least one selected from the group consisting of stearyl alcohol and cetanol. The content of the emulsifying stabilizer in the human hair dyeing composition may be, for example, 1.00% by mass or more and 10.0% by mass or 3.00% by mass or more and 8.00% by mass or less, based on the total amount of the composition.

[0099] As the polymer, one that is commonly used in hair dyeing compositions can be used, for example, one that is commonly used as a thickener in hair dyeing compositions. The polymer may be at least one selected from the group consisting of vinyl polymers containing vinylpyrrolidone as a monomer unit (e.g., polyvinylpyrrolidone or vinyl acetate / vinylpyrrolidone copolymer), cationic polymers (polyquaternium, cationized cellulose derivatives, cationized guar gum, cationized starch, polymers or copolymers of diallyl quaternary ammonium salt, quaternized polyvinylpyrrolidone), polyalkyleneimines (e.g., polyethyleneimine), silicone polymers (e.g., dimethylpolysiloxane, polyether-modified silicone or amino-modified silicone, polyether-alkyl copolymerized silicone, polyglycerin-modified silicone, polyglycerin-alkyl copolymerized silicone, amino-modified silicone, dimethiconol, silicone emulsion), and vinyl polymers containing (meth)acrylic acid or its ester as a monomer unit. The polymer content in the human hair dyeing composition may be, for example, 0.03% by mass or more and 3.00% by mass or 0.10% by mass or more and 1.00% by mass or less, based on the total amount of the composition.

[0100] As the acid, one that is commonly used in hair dyeing compositions may be used. The acid may be an inorganic acid or an organic acid, for example. Examples of inorganic acids include hydrochloric acid and sulfuric acid, and examples of organic acids include lactic acid, sodium lactate, citric acid, sodium citrate, succinic acid, and sodium succinate, and in one embodiment, citric acid may be used. The acid content in the human hair dyeing composition may be, for example, 0.005% by mass or more and 0.10% by mass or 0.01% by mass or more and 0.05% by mass or less, based on the total amount of the composition.

[0101] As a chelating agent, those commonly used in hair dyeing compositions can be used. Examples of chelating agents include ethylenediaminetetraacetic acid (EDTA), ethylenediaminetetraacetic acid salt (sodium salt (sodium edetate: Japanese Pharmacopoeia, EDTA-2Na, etc.), potassium salt, etc.), phytic acid, gluconic acid, polyphosphate, metaphosphate, preferably sodium edetate, and in one embodiment, at least one selected from the group consisting of EDTA and sodium edetate. The content of the chelating agent in the human hair dyeing composition may be, for example, 0.005% by mass or more and 0.10% by mass or 0.01% by mass or more and 0.08% by mass, based on the total amount of the composition.

[0102] The amount of additives in a human hair dyeing composition may be, for example, 1.00% by mass or more, 4.00% by mass or more, 7.00% by mass or more, or 10.0% by mass or more, based on the total amount of the composition, and may also be 40.0% by mass or less, 30.0% by mass or less, 20.0% by mass or less, or 15.0% by mass or less.

[0103] The pH of the human hair dyeing composition may be, for example, 6.0 or higher, 7.0 or higher, 8.0 or higher, 8.5 or higher, 9.0 or higher, or 9.5 or higher, and may also be 12.0 or lower, 11.5 or lower, 11.0 or lower, or 10.5 or lower. In one embodiment, the pH of the human hair dyeing composition may be 6.0 to 12.0, 7.0 to 12.0, 8.0 to 12.0, 8.5 to 11.5, 9.0 to 11.0, or 9.5 to 10.5.

[0104] The viscosity of the human hair dyeing composition may be, for example, 3,000 to 100,000 mPa·s, 5,000 to 90,000 mPa·s, 10,000 to 70,000 mPa·s, or 20,000 to 50,000 mPa·s. Viscosity (25°C) refers to the viscosity measured using a single-cylindrical rotational viscometer (Brookfield type viscometer) in accordance with the viscosity measurement method described in the general test methods of the 17th edition of the Japanese Pharmacopoeia. Specifically, it refers to the value measured using TV-10M (manufactured by Toki Sangyo Co., Ltd.), and the selection of conditions such as rotor and rotation speed shall be in accordance with the instruction manual of this machine, and the viscosity at 25°C shall be measured.

[0105] The following is a description of a single-cylinder rotational viscometer. A single-cylinder rotational viscometer is a viscometer that measures the torque when a cylinder in a liquid is rotated at a constant angular velocity. The viscosity η of the liquid is calculated by the following formula after experimentally determining the apparatus constant KB using a viscometer calibration standard solution. η = KB × T / ω η: Viscosity of liquid (mPa·s) KB: Equipment constant (rad / cm 3 ) ω: Angular velocity (rad / s) T: Torque acting on the cylindrical surface (10 -7 N·m)

[0106] A human hair dyeing composition is a composition applied to human hair for dyeing human hair. A human hair dyeing composition may be applied to human hair, for example, by application or dispensing. The form of a human hair dyeing composition may be, for example, a liquid or a semi-solid. A human hair dyeing composition may be applied as a liquid, cream, hair milk, gel, paste, mousse, or aerosol, and in one embodiment, it may be applied as a liquid, cream, hair milk, gel, or paste. A human hair dyeing composition may be, for example, a composition solely for the purpose of dyeing hair, or it may be a shampoo, conditioner, or treatment that can also dye hair. A human hair dyeing composition may be, for example, a composition for dyeing gray hair black. A human hair dyeing composition may be a hair dye that is a quasi-drug in Japan or a hair dye that is a cosmetic in Japan, and in one embodiment, it may be a hair dye. In one embodiment, a human hair dyeing composition may be a hair dye composition or a permanent hair dye composition. In one embodiment, the human hair dyeing composition may also be an air-oxidation type hair dyeing composition.

[0107] A human hair dyeing composition may be a single-component or multi-component composition, and in one embodiment, it may be a single-component composition. A single-component human hair dyeing composition is a composition in which all components of the composition are applied as a single agent when applied to human hair. A single-component human hair dyeing composition may be manufactured, stored, and distributed in a state containing all its components, or it may have two or more components at the stage of manufacture, storage, or distribution, and be prepared just before use to contain all components. A multi-component human hair dyeing composition is a composition in which the components of the composition are divided into two or more agents and applied when applied to human hair, and all components of the human hair dyeing composition are mixed on the applied surface. In a multi-component human hair dyeing composition, for example, component (A), component (B), and / or component (C) may be applied as different agents. In a multi-component human hair dyeing composition, for example, the above two or more agents may be applied simultaneously.

[0108] The human hair dyeing composition may be housed in a suitable container according to its form, such as a sachet, tube, aerosol, bottle, pump, jar, or capsule. In one embodiment, the human hair dyeing composition may be housed in an airtight and alkali-resistant sachet. A sachet is a bag-shaped packaging container divided into individual units for use. Examples of airtight and alkali-resistant sachets include those with an inner surface made of aluminum or resin, and those with an alkali-resistant laminate coating.

[0109] The human hair dyeing composition can be used for hair dyeing, for example, by following the procedure shown below. First, apply the human hair dyeing composition to human hair. Next, maintain the application of the human hair dyeing composition as needed. Finally, rinse off the applied human hair dyeing composition.

[0110] The amount of the human hair dyeing composition to be applied to hair may be, for example, 0.50 g or more, 10 g or more, 15 g or more, or 30 g or more per dyeing session, and may also be 200 g or less, 150 g or less, 100 g or less, 80 g or less, or 60 g or less.

[0111] The time for which the human hair dye composition is applied may be, for example, 1 minute or more, 3 minutes or more, 5 minutes or more, or 3 minutes or more, and may be 2 hours or less, 1 hour 30 minutes or less, 1 hour or less, 40 minutes or less, 30 minutes or less, 20 minutes or less, or 15 minutes or less. [Examples]

[0112] The present disclosure will be described in more detail below with reference to examples, but this disclosure should not be construed as being limited to these examples. Unless otherwise specified, the percentages of each component in these examples are given in mass percent.

[0113] The materials used in the following examples and their sources are as follows: As a hair color dye, 5,6-dihydroxyindole (DHI, CAS No.: 3131-52-0) was purchased from Shanghai PI Chemicals. As cationic polymers, poly-L-lysine (α-PL) was provided by Fujifilm Wako Pure Chemical Corporation, ε-poly-L-lysine (ε-PL) by JNC Corporation, and poly[oxyethylene (dimethylimino)propyl (dimethylimino)ethylene] (PA-1) by Nikka Chemical Co., Ltd. The standard substance N / 400 polyvinyl sulfate potassium (PVSK) and the colloidal titration indicator toluidine blue (TB) were purchased from Fujifilm Wako Pure Chemical Corporation. The number average molecular weights (g / mol) were 110,000 (70,000-150,000) for α-PL, 4,090 for ε-PL, and 63,000 for PA-1. The cationic fluorescent reagent Rhodamine 6G was purchased from Fujifilm Wako Pure Chemical Industries, Ltd. The bundles of white hair were purchased commercially from Viewlux Corporation.

[0114] <Test Example 1: Evaluation of improved hair dyeability through treatment with a hair dyeing stimulant> As shown in Table 1, 0.5 wt% α-PL aqueous solution (Comparative Example 1), ε-PL aqueous solution (Example 1), and PA-1 aqueous solution (Example 2) were prepared at pH 7.0 (hair dyeing accelerators). Gray hair bundles were immersed in each aqueous solution for 5 minutes and allowed to air dry. A hair dyeing composition containing DHI at pH 10.0 was prepared, with the composition shown in Table 2, without exposure to air. Approximately 4 g of the hair dyeing composition was applied uniformly to both sides of one hair bundle (approximately 2 g) over a period of 1 minute. Subsequently, the hair bundles were placed in a constant temperature and humidity chamber set to room temperature 30°C and humidity 55% for 2.5 minutes, then flipped over and placed for another 2.5 minutes. After that, the hair bundles were washed with tap water for 1 minute and dried with a hair dryer. The above hair dyeing process was repeated three times. After dyeing, the dyeability was evaluated by optical measurement and visual inspection. For optical measurement evaluation, the reflectance spectrum of each hair strand was measured using a UV-Vis spectrophotometer (JASCO Corporation, V-650). Dyeability was evaluated using the color difference ΔE*ab, calculated using the following formula based on the lightness (L*), hue (a*), and chroma (b*) obtained from the measured reflectance spectrum. Note that ΔE*ab was calculated using a white calibration plate as the reference. ΔE*ab=[(ΔL*) 2 +(Δa*) 2 +(Δb*) 2 ] 1 / 2

[0115] In the visual evaluation, contrast was assessed using the following three-level scale. ◎: Clearly perceives contrast ○: I feel the contrast. △: I don't feel much contrast.

[0116] [Table 1]

[0117] [Table 2]

[0118] Table 1 shows the results of the optical measurement and visual evaluation of hair dyeability obtained above. Figure 1 is a photograph of hair dyed with a DHI-containing hair dye composition under indoor lighting, showing the results when no pretreatment with a hair dye accelerator was performed (Control) or when pretreatment was performed with a hair dye accelerator containing α-PL, ε-PL, or PA-1. Figure 2 shows the ΔE*ab values ​​of hair dyed with a DHI-containing hair dye composition, showing the results when no pretreatment with a hair dye accelerator was performed (Control) or when pretreatment was performed with a hair dye accelerator containing α-PL, ε-PL, or PA-1. In Figure 2, the results are shown as mean ± standard deviation, and ns, *, and ** indicate that the p-values ​​in Student's t-test were p*<0.05, p**<0.01, and p***<0.001, respectively. According to Table 1, Figure 1, and Figure 2, when pre-treatment was performed with a hair dyeing accelerator containing the cationic polymer ε-PL or PA-1, an improvement in ΔE*ab was observed, and the improvement was particularly significant when pre-treatment was performed with a hair dyeing accelerator containing PA-1. Furthermore, according to Table 1, visual evaluation showed that the contrast was greater when pre-treatment was performed with a hair dyeing accelerator containing the cationic polymer ε-PL or PA-1 (Examples 1 and 2) than when pre-treatment was performed with a hair dyeing accelerator containing α-PL (Comparative Examples 1 and 2). From these results, it became clear that hair dyeing properties with DHI compounds or their salts are improved when using a hair dyeing accelerator containing a cationic polymer.

[0119] <Test Example 2: Measurement of the degree of cationization of cationic polymers> The degree of cationization of α-PL, ε-PL, and PA-1 used in Test Example 1 was measured in acidic, neutral, and basic aqueous solutions. 50 ppm aqueous solutions of α-PL, ε-PL, or PA-1 were adjusted to pH 3.0, pH 7.0, or pH 10.0 using monoethanolamine and lactic acid. 100 μL of TB was mixed into 10 mL of each solution, and then PVSK was added dropwise using a burette. The color change of the solution (from blue to reddish-purple) was visually observed. The degree of cationization of each cationic polymer was evaluated based on the amount of PVSK added until the color change occurred.

[0120] Table 3 shows the charge (degree of cationization) of α-PL, ε-PL, and PA-1 in aqueous solutions at pH 3.0, pH 7.0, and pH 10.0. According to Table 3, α-PL, which did not show any staining-promoting effect in Test Example 1, had a charge of 0 meq / g at pH 7.0, while ε-PL and PA-1, which showed staining-promoting effects in Test Example 1, had a charge exceeding 0 meq / g at pH 7.0. Therefore, from the results of Test Examples 1 and 2, it became clear that cationic polymers with a charge exceeding 0 meq / g at pH 7.0 have excellent staining-promoting effects.

[0121] [Table 3]

[0122] <Test Example 3: Evaluation of the surface potential of hair treated with a hair dyeing stimulant> Hair strands were immersed for 5 minutes in a 0.5 wt% pH 7.0 α-PL aqueous solution, ε-PL aqueous solution, or PA-1 aqueous solution, and then air-dried. After drying, the surface potential of each hair strand was measured using a SurPass3 device manufactured by Anton Paar GmbH. A 1.0 mmol / L KCl aqueous solution was used as the electrolyte, and the pH was adjusted with a 0.1 mol / L sodium hydroxide solution or a 0.05 mol / L hydrochloric acid solution. As a control, the zeta potential of hair that had not been treated with a hair dye stimulant was also measured in the same manner.

[0123] Figure 3 shows the pH dependence of the surface potential of hair not treated with a hair dye accelerator. Figure 4 shows the surface potential at pH 10.0 of hair not treated with a hair dye accelerator (Control) or hair treated with a hair dye accelerator containing α-PL, ε-PL, or PA-1. In Figure 4, the results are shown as mean ± standard deviation, and * and *** indicate that the p-values ​​in Student's t-test were p* < 0.05, p** < 0.01, and p*** < 0.001, respectively. According to Figure 3, the zeta potential of gray hair strands was 0 mV around pH 3 and remained constant at around -10 mV above pH 4. Also, according to Figure 4, an increase in surface potential at pH 10.0 was observed only in hair treated with a hair dye accelerator containing PA-1, which was in good agreement with the degree of cationization at pH 10.0 of each polymer shown in Table 2. Since DHI compounds develop color under conditions of approximately pH 10.0, the observed increase in surface potential at pH 10.0 in hair treated with a hair dyeing accelerant containing PA-1 is consistent with the particularly excellent hair dyeing performance observed in Test Example 1 when treated with a hair dyeing accelerant containing PA-1.

[0124] <Test Example 4: Fluorescence observation of the surface potential of hair treated with a hair dyeing stimulant> A 10 μM rhodamine 6G aqueous solution was prepared and adjusted to pH 10.0 using monoethanolamine. Hair bundles were immersed for 5 minutes in a 0.5 wt% pH 7.0 α-PL aqueous solution, ε-PL aqueous solution, or PA-1 aqueous solution, and then air-dried. After drying, the hair bundles were immersed in a 10 μM rhodamine 6G aqueous solution for 10 seconds, washed with distilled water for 10 seconds, and then towel-dried. Subsequently, the hair surface was observed using a fluorescence microscope (Olympus IX71) and a confocal unit (Hamamatsu Photonics K.K., MAICO MEMS confocal unit C15890 series). Brightness was calculated from these observed images using image analysis software (Fiji).

[0125] Figure 5 shows the fluorescence images and fluorescence intensity of hair labeled with the cationic fluorescent dye rhodamine 6G after pretreatment with a hair dyeing accelerator (Control) or after pretreatment with a hair dyeing accelerator containing α-PL, ε-PL, or PA-1. In Figure 5, the results are shown as mean ± standard deviation, and ns and *** indicate that the p-values ​​in Student's t-test were p*<0.05, p**<0.01, and p***<0.001, respectively. According to the results in Figure 5, hair pretreated with a hair dyeing accelerator containing ε-PL or PA-1, which improved dyeability in Test Example 1, was difficult to dye with the cationic fluorescent dye, and hair pretreated with a hair dyeing accelerator containing PA-1, which particularly improved dyeability in Test Example 1, was even more difficult to dye with the cationic fluorescent dye. The results from Test Examples 1-4 suggest that cationic polymers improve the dyeability by DHI compounds by positively charging the hair surface, and among them, polymers with a positive degree of cationization even under basic conditions of around pH 10, such as PA-1, were shown to particularly improve the dyeability by DHI compounds.

[0126] <Example 5: Elucidation of dye penetration pathways using fluorescent dyes> The surface of hair was observed using a confocal laser scanning microscope (Olympus FV1000 IX81). Then, several drops of 10 μM 6G rhodamine aqueous solution were added to the observed hair samples, a coverslip was placed over them, and the hair surface condition was observed again 10 seconds, 5 minutes, 10 minutes, and 20 minutes after the dye was added. Brightness integrated values ​​were calculated from these observed images using image analysis software (Fiji).

[0127] Figure 6 shows the fluorescence images and fluorescence intensity of hair 10 seconds, 5 minutes, 10 minutes, and 20 minutes after dropping a rhodamine 6G aqueous solution. It was observed that the brightness increased only at the edges of the cuticle over time, and the integrated brightness value reached a plateau after about 10 minutes.

[0128] <Test Example 6: Evaluation of multi-coloring due to hair dyeing stimulant treatment> As a pretreatment, an aqueous solution of a cationic polymer and purified water (control), whose compositions are shown in Table 4, were prepared. PA-1 was used as the cationic polymer, and a 0.5 wt% PA-1 aqueous solution with a pH of 7.0 was prepared. Bundles of gray hair (Beaulux, 10.5 cm in length) were immersed in each aqueous solution for 5 minutes, and then the bundles were dried with a hairdryer. A hair dyeing composition, whose composition is shown in Table 5, was prepared according to a conventional method. 1.5 g of the hair dyeing composition was applied to the pretreated bundles of hair, spread evenly throughout the hair, and then the hair was left to stand for 5 minutes. The bundles of hair were washed with 40°C tap water for 1 minute and dried with a hairdryer. The above hair dyeing process was repeated three times. After dyeing, the dyeability was evaluated based on the hue (a*) of the dyed hair. For hue (a*), we used a Konica Minolta CR-5 colorimeter to measure hue (a*) at three different points on the surface of dyed hair. Based on these measurements, we used the average value of the difference in hue (a*) at each point, calculated using the following formula. Δa* = "a* in hair pre-treated with various cationic polymers" -"a* in control hair pre-treated with purified water"

[0129] The results are shown in Table 4. Hair bundles pretreated with PA-1 aqueous solution had a larger Δa* value compared to hair bundles pretreated with purified water.

[0130] [Table 4]

[0131] [Table 5]

[0132] <Test Example 7: Evaluation of hair dyeability after application of shampoo containing a hair dyeing stimulant 1> As a pretreatment, a shampoo (hair dyeing accelerator) with the composition shown in Table 6 was prepared. As shown in Table 6, the shampoo of Example 6 contains PA-1 as a cationic polymer, while the shampoo of Comparative Example 3 does not contain a cationic polymer. A bundle of gray hair (made by Beaulux, 10.5 cm in length) was immersed in purified water at 40°C, then the hair was removed from the purified water and washed with the prepared shampoo. For the hair dyeing treatment, a hair dyeing composition with the composition shown in Table 7 was prepared according to a conventional method, 1.5 g of the hair dyeing composition was applied to the pretreated hair bundle, spread evenly over the hair, and then left to stand for 10 minutes. The hair bundle was washed with tap water at 40°C for 1 minute and dried with a hair dryer. As shown in Table 7, two types of hair dyeing compositions were tested: one with a DHI concentration of 0.15 wt% and another with a DHI concentration of 0.05 wt%. The above pretreatment and hair dyeing treatment were repeated three times. The dyeability was evaluated based on the color difference ΔE*ab in the dyed hair. ΔE*ab was calculated using a Konica Minolta CR-5 colorimeter, based on the lightness (L*), hue (a*), and chroma (b*) measured at three different points on the surface of the dyed hair. The average value of ΔE*ab at each point was calculated using the following formula. The calculation was based on a white calibration plate of ΔE*ab. ΔE*ab=[(ΔL*) 2 +(Δa*) 2 +(Δb*) 2 ] 1 / 2

[0133] [Table 6]

[0134] [Table 7]

[0135] The results are shown in Table 8. According to Table 8, when pre-treatment was performed with the shampoo of Example 6, which contains PA-1 as a cationic polymer, ΔE*ab was greater than when pre-treatment was performed with the shampoo of Comparative Example 3, which does not contain a cationic polymer. This demonstrates that shampoos containing cationic polymers exhibit an effect of improving hair dyeability.

[0136] [Table 8]

[0137] <Test Example 8: Improvement of hair fastness after application of shampoo containing a hair dye stimulant> In Comparative Example 3 and Example 6, hair bundles dyed with 0.5% DHI, as used in Test Example 7, were immersed in 100 ml of 1% sodium lauryl sulfate aqueous solution and gently stirred for 30 minutes. After that, the hair bundles were removed, rinsed with running water, and dried with a hairdryer. The color difference ΔE*ab of the dried hair was measured using a white calibration plate as a reference, in the same manner as in Test Example 7. The ΔE*ab values ​​shown in Table 9 were calculated by subtracting the values ​​of lightness (L*), hue (a*), and chroma (b*) obtained in Test Example 7 from the values ​​of lightness (L*), hue (a*), and chroma (b*) obtained in Test Example 7, using the white calibration plate as a reference, as the respective change amounts (ΔL*, Δa*, Δb*), and following the formula shown in Test Example 7. A larger value of ΔE*ab indicates that the brightness (L*), hue (a*), and saturation (b*) after treatment are lower compared to before treatment with a 1% sodium lauryl sulfate aqueous solution, meaning that more color fading occurred as a result of the treatment.

[0138] The results are shown in Table 9. According to Table 9, when pre-treatment was performed with the shampoo of Example 6, which contains PA-1 as a cationic polymer, the ΔE*ab (referenced to before treatment with 1% sodium lauryl sulfate aqueous solution) was smaller than when pre-treatment was performed with the shampoo of Comparative Example 3, which does not contain a cationic polymer, indicating that the hair dye was more durable.

[0139] [Table 9]

[0140] <Test Example 9: Evaluation of hair dyeability after application of shampoo containing a hair dyeing stimulant 2> As a model formulation of shampoo containing 0.5 wt% PA-1, the shampoo shown as Example 6 in Table 6, which was used in Test Example 7, was used. After immersing bundles of white hair (Beaulux, 10.5 cm in length) in purified water at 40°C, the hair was removed from the purified water and washed with the prepared shampoo. For the hair dyeing treatment, a hair dyeing composition shown in Table 10 was prepared according to a conventional method, 1.5 g of the hair dyeing composition was applied to the pre-treated hair bundles, spread evenly over the hair, and then left to stand for 10 minutes. The hair bundles were washed with tap water at 40°C for 1 minute and dried with a hairdryer. The color difference ΔE*ab of the hair after drying was evaluated in the same manner as in Test Example 7. ΔE*ab was calculated using a white calibration plate as the reference. As shown in Table 10, the hair dyeing compositions used contain basic dyes and / or HC dyes, which are direct dyes, in addition to DHI.

[0141] [Table 10]

[0142] The results are shown in Table 10. According to these results, hair pretreated with the shampoo of Example 6, which contains PA-1 as a cationic polymer, was highly efficiently dyed with a hair dyeing composition containing not only DHI but also a direct dye, which is a basic dye and / or an HC dye. This confirms that pretreatment with a shampoo containing a cationic polymer can promote hair dyeing with a hair dyeing composition in the range from black to light brown. Furthermore, it was confirmed that pretreatment with a shampoo containing a cationic polymer can also promote hair dyeing with a hair dyeing composition containing DHI and a direct dye. These results confirm that pretreatment of hair with PA-1 shampoo improves dyeability with a hair dyeing composition containing DHI and a direct dye.< / number> < / color> < / number> < / color>

Claims

1. A hair dyeing accelerant for human hair containing poly[oxyethylene (dimethylimino)propyl (dimethylimino)ethylene] and / or ε-poly-L-lysine.

2. The hair dyeing accelerant according to claim 1, comprising poly[oxyethylene (dimethylimino)propyl (dimethylimino)ethylene].

3. A hair dyeing accelerator according to claim 1 or 2, for promoting hair dyeing with 5,6-dihydroxyindoles, 5,6-dihydroxyindolines, or salts thereof.

4. A method for promoting hair dyeing, comprising contacting human hair with poly[oxyethylene (dimethylimino)propyl (dimethylimino)ethylene] and / or ε-poly-L-lysine.

5. A hair dyeing method comprising contacting human hair with poly[oxyethylene (dimethylimino)propyl (dimethylimino)ethylene] and / or ε-poly-L-lysine, and contacting human hair with 5,6-dihydroxyindoles, 5,6-dihydroxyindolines, or salts thereof.

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