Hair treatment method, hair composition, medulla filler, gray hair treatment agent, and hair treatment agent

Abstract

To provide hair treatment methods suitable for modifying the inside of hair.SOLUTION: Provided is a hair treatment method that reduces a void of hair medulla by bringing a hair composition that contains components (A) and (B) and meets the requirements (i) and / or (ii) into contact with the hair. The component (A) is at least one selected from the group consisting of hydrolyzed proteins, amino acids, and derivatives thereof. The component (B) is a penetrant. (i) is to contain a reduced hydrolyzed protein that can act as a reducing agent, as component (A). (ii) is to further contain a reducing agent as component (C). The pH of the hair composition at 25°C is 3.0 or more and less than 8.0.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a hair treatment method, a hair composition, a medulla filler, a gray hair treatment agent, and a hair treatment agent. More specifically, the present invention relates to a hair treatment method, a hair composition, a medulla filler, a gray hair treatment agent, and a hair treatment agent suitable for modifying the inside of hair.

Background Art

[0002] It is known that the texture of hair such as gloss, firmness, and cohesion decreases with aging. In addition, hair is damaged by chemical treatments such as hair color and perm, and physical treatments using heat such as hair irons and dryers. Examples of damage are the peeling of the cuticle on the surface of the hair and the cavitation inside the hair. The cavitation inside the hair progresses, for example, by the outflow of lipids inside the hair.

[0003] To address the above problems, hair treatment agents containing specific compounds have been proposed. Patent Document 1 discloses an oil-in-water emulsified hair cosmetic having a specific silicone and a cationic polymer. Patent Document 2 discloses a two-agent type hair treatment agent having a first agent to be applied to the hair and a second agent to be applied without washing away the first agent. Patent Document 3 discloses a hair cosmetic combining a specific lactone derivative, a sunflower seed extract, a fatty acid liquid at 25°C, and an ester oil. Patent Document 4 discloses an oily hair cosmetic containing dimethylpolysiloxane, dimethiconol, and isononyl isononanoate.

[0004] Hair is composed of the cuticle (hair cuticle) that covers the surface of the hair, the cortex (hair cortex) that is inside the hair, and the medulla (hair medulla) that is in the center of the hair. It has also been proposed to improve the texture of hair by having hair treatment agents act on the inside of the hair rather than on the surface. Patent Document 5 discloses a medulla care agent having a specific functional group. The molecular weight of the active ingredient of the medulla care agent used in the examples of Patent Document 5 is, for example, less than 200. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2018-172378 [Patent Document 2] Patent No. 6161265 [Patent Document 3] Japanese Patent Publication No. 2017-25004 [Patent Document 4] Japanese Patent Publication No. 2019-99533 [Patent Document 5] Japanese Patent Publication No. 2000-109411 [Overview of the project] [Problems that the invention aims to solve]

[0006] The cosmetics or treatments disclosed in Patent Documents 1 to 4 provide polymers or oils to the surface of hair to temporarily improve the texture of hair. However, these cosmetics or treatments have difficulty modifying the inside of the hair. The effects of polymers or oils attached to the surface of the hair are not long-lasting. The attachment of polymers or oils can also make the hair sticky or give it an unnatural texture. In contrast, Patent Document 5 attempts to modify the inside of the hair. However, according to the inventors' research, the improvement in hair texture by this technology is limited and its duration is not sufficient.

[0007] The object of the present invention is to provide a novel hair treatment method suitable for modifying the inside of hair, and a novel hair composition suitable for modifying the inside of hair. [Means for solving the problem]

[0008] The present invention The present invention provides a hair treatment method that reduces the voids in the hair medulla by contacting the hair with a hair composition containing the following components (A) and (B), having a pH of 3.0 or higher and less than 8.0 at 25°C, and satisfying at least one of the following (i) and (ii). (i) The component (A) includes a reduced hydrolyzed protein that can act as a reducing agent. (ii) Further comprising the following component (C): (A) At least one selected from the group consisting of hydrolyzed proteins, amino acids, and their derivatives. (B) Penetrating agent (C) Reducing agent

[0009] From another aspect, the present invention Contacting hair with a hair composition comprising at least one selected from the group consisting of hydrolyzed proteins, amino acids, and their derivatives, Maintain contact between the hair composition and the hair until at least one component contained in the hair composition penetrates into the hair, thereby substantially filling the hair medulla. The present invention provides a hair treatment method that includes [a specific component].

[0010] From another aspect, the present invention Contacting hair having a black medulla with a hair composition containing at least one selected from the group consisting of hydrolyzed proteins, amino acids, and their derivatives, Maintain contact between the hair composition and the hair until the black medulla changes into a white medulla, The present invention provides a hair treatment method that includes [a specific component].

[0011] From another aspect, the present invention provides a hair composition for modifying the medulla of hair, comprising the following components (A) and (B), having a pH at 25°C of 3.0 or more and less than 8.0, and at least one selected from the group consisting of the following (i) and (ii) being satisfied, and provides a hair composition. (i) As the component (A), it contains a reduced hydrolyzed protein that can act as a reducing agent. (ii) It further contains the following component (C). (A) At least one selected from the group consisting of hydrolyzed proteins, amino acids, and their derivatives (B) A penetrant (C) A reducing agent

[0012] From another aspect, the present invention[[ID=二十六]] provides a medulla filler containing the hair composition according to the present invention.

[0013] From another aspect, the present invention provides a gray hair treatment agent containing the hair composition according to the present invention.

[0014] From another aspect, the present invention provides a hair treatment agent comprising a first agent containing the hair composition according to the present invention and a second agent containing an oxidizing agent.

Advantages of the Invention

[0015] According to the present invention, a hair treatment method suitable for modifying the interior of hair is provided. Further, according to the present invention, a hair composition suitable for modifying the interior of hair is provided. [[ID=5))

Brief Description of the Drawings

[0016] [[ID=\54]] [Figure 1] Figure 1 is an image of human hair treated with the hair composition according to Example 1 observed by an optical microscope. [Figure 2]Figure 2 shows an image of human hair treated with the hair composition according to Example 2, as observed with an optical microscope. [Figure 3] Figure 3 is an image of human hair treated with the hair composition according to Example 4, as observed with an optical microscope. [Figure 4] Figure 4 shows an image of human hair treated with the hair composition according to Example 11, as observed with an optical microscope. [Figure 5] Figure 5 shows an image of human hair treated with the hair composition according to Comparative Example 3, as observed with an optical microscope. [Figure 6] Figure 6 shows an image of human hair treated with the hair composition according to Comparative Example 4, as observed with an optical microscope. [Figure 7] Figure 7 shows an image of human hair treated with the hair composition according to Comparative Example 5, as observed with an optical microscope. [Figure 8] Figure 8 shows an image of human hair treated with the hair composition according to Comparative Example 6, as observed with an optical microscope. [Figure 9] Figure 9 shows an image of human hair treated with the hair composition according to Comparative Example 9, as observed with an optical microscope. [Figure 10] Figure 10 shows an image of human hair treated with the hair composition according to Comparative Example 10, as observed with an optical microscope. [Figure 11] Figure 11 is an image of human hair treated with the hair composition according to Comparative Example 11, as observed with an optical microscope. [Figure 12] Figure 12 shows an image of human hair that has not been treated with a hair composition, as observed with an optical microscope. [Figure 13] Figure 13 shows photographs of hair strands treated with the hair compositions according to Example 2, Comparative Example 3, and Comparative Example 9, followed by treatment with a basic hair dye. [Figure 14] Figure 14 is a photograph of hair strands treated with the hair compositions according to Example 2 and Comparative Example 5, followed by the application of a straightening iron. [Modes for carrying out the invention]

[0017] Embodiments of the present invention will be described below. However, the following description is not limited to any particular form of the present invention.

[0018] The hair medulla typically has a porous structure composed of fibrous material. Damage to the hair due to chemical or physical treatment, or aging, increases the number of voids within the porous structure of the medulla. In some hairs, the medulla may be composed of voids locally or entirely. According to this embodiment, the hair medulla can be modified. Modification of the medulla is achieved, for example, by reducing the number of voids in the medulla.

[0019] A hair composition according to one embodiment of the present invention comprises components (A) to (C). (A) At least one selected from the group consisting of hydrolyzed proteins, amino acids, and their derivatives. (B) Penetrating agent (C) Reducing agent

[0020] A hair composition according to another embodiment of the present invention comprises components (A1) and (B). (A1) At least one selected from the group consisting of reduced hydrolyzed proteins and their derivatives (B) Penetrating agent In this form, component (A1) can also act as a reducing agent, so the inclusion of component (C) is optional.

[0021] The pH of these hair compositions (hereinafter referred to as the hair compositions according to this embodiment) is 3.0 or higher and less than 8.0 at 25°C.

[0022] The hair composition according to this embodiment can improve the texture of the hair, specifically by improving its shine, firmness, body, and manageability.

[0023] The hair composition according to this embodiment makes it possible to reduce the voids in the hair medulla. This effect can reduce the voids that are large within the medulla. Conventional medulla care agents (see Patent Document 5) have limitations in their effect of reducing medulla voids, and the duration of this effect is not sufficient.

[0024] In this specification, when observing hair under transmitted light using an optical microscope set to 500x magnification, a medulla in which the black void in the center of the hair extends across the longitudinal section of the medulla, in other words, the cross-section of the medulla along the axial direction of the hair, is called a "black medulla" (see Figure 12 as an example), and a medulla that is filled without such an extended void and appears white overall is called a "white medulla" (see Figure 1 as an example). For observing the hair medulla, hair that has been in contact with the hair composition, washed with water, and air-dried is used. Details of the medulla observation method using transmitted light are described in the Examples section.

[0025] Black medulla is frequently observed in damaged hair, especially gray hair. In white medulla, the amount of light scattered by the hair is suppressed, and the amount of light transmitted through the hair increases. As a result, gray hair appears more transparent, making it less noticeable. Generally, white medulla contains more fibrous material than black medulla, resulting in fewer voids. However, since medulla inherently has a porous structure, fine voids also exist in white medulla. Therefore, if microscopic observation using an electron microscope is applied, voids can usually be observed in white medulla as well. In addition, fibrous material constituting the porous structure may actually be present in the voids of black medulla. However, according to the inventors' research, the difference between black medulla and white medulla greatly affects the degree of light scattering, which is a factor influencing the luster and texture of the hair. The hair composition according to this embodiment enables the transformation from black medulla to white medulla. However, the hair treated with the hair composition according to this embodiment is not limited to hair having a black medulla.

[0026] When hair is damaged, substances such as moisture can easily penetrate into the hair shaft. This can cause hair components, such as the cortex, to swell, resulting in a reduction of medulla voids. In this case, when observing the hair under transmitted light using an optical microscope, the scattering of transmitted light is suppressed, making it appear as if a white medulla has formed. However, because the hair is damaged, the substances that have penetrated into the hair shaft easily leak out. Therefore, there are limitations to the effect of reducing medulla voids, and the persistence of this effect is not sufficient. In this case, it is difficult to say that the inside of the hair has been modified. The hair composition according to this embodiment can, for example, act on the medulla when the hair is less damaged, thereby reducing medulla voids. In addition, the hair composition does not easily leak out of the hair even when the hair is dried. Therefore, the hair composition according to this embodiment can also improve the persistence of the effect of reducing medulla voids.

[0027] The hair composition according to this embodiment is useful, for example, as a medulla filler. Regardless of its specific name, a medulla filler is an agent whose efficacy includes the progression of medulla filling or the effects associated therewith. In other words, a medulla filler may be sold as a hair conditioner whose efficacy includes, for example, the improvement of hair texture due to medulla filling. The degree of medulla filling can be confirmed by observation using an optical microscope, as described above. If, in this observation, voids that have spread to the extent that they traverse the longitudinal cross-section along the axial direction of the medulla have been eliminated, the medulla can be considered to be "substantially filled." To the best of the inventors' knowledge, no treatment agent that modifies the inside of hair to the extent that the medulla is substantially filled has been known until now.

[0028] Surprisingly, it has been found that using the hair composition according to this embodiment has the effect of making gray hair less visible. A significant reduction in the voids in the medulla, preferably substantial filling of the medulla, increases transparency, especially in gray hair. And the presence of gray hair becomes less noticeable, especially when gray hair is partially present in the hair, in other words, in hair mixed with gray. Furthermore, the texture of the gray hair itself is also improved by the improved transparency. Moreover, this effect can be achieved along with an improvement in the texture of the hair. This is a feature that is difficult to obtain from conventional general gray hair dyes, which often damage the hair. Due to this aspect, the hair composition according to this embodiment can also be used as a gray hair treatment agent. Conventional gray hair treatment agents contain compounds that act directly as hair dyes or that can produce hair dyes. In contrast, the gray hair treatment agent described above, i.e., the gray hair treatment agent according to this embodiment, does not have to contain compounds for dyeing hair. In other words, in the gray hair treatment agent according to this embodiment, a hair dye or a compound that can produce a hair dye is an optional component. To the best of our knowledge, no treatment agent has been known to improve the texture of gray hair or to make partially gray hair less noticeable.

[0029] The gray hair treatment agent according to this embodiment, regardless of its specific name, is an agent whose efficacy includes improving the texture of gray hair or making it less visible. The gray hair treatment agent may be sold under names such as hair conditioner or other names.

[0030] Traditionally, oxidative hair dyes containing oxidative dyes have been used to make gray hair less noticeable. However, using oxidative hair dyes can easily damage hair. In other words, conventional oxidative hair dyes easily decompose the fibrous material contained in the medulla. Although gray hair is initially dyed by oxidative hair dyes, the medulla inside becomes hollowed out. In contrast, the hair composition according to this embodiment actually reduces the voids in the medulla. In other words, the hair composition according to this embodiment makes it possible to repair gray hair from within. As a result, gray hair with increased transparency can be obtained.

[0031] The hair modification using the hair composition according to this embodiment can have high durability. The durability of the hair modification is particularly noticeable when component (A) contains hydrolyzed proteins, amino acids, or derivatives thereof with a large molecular weight. Components (A) and (C) are thought to break the disulfide bonds in the hair, promoting the penetration of components and allowing the component with a large molecular weight (A) to act effectively inside the hair. Components with a small molecular weight, such as lower alcohols, penetrate the inside of the hair easily but are easily washed away during shampooing, etc. It is also desirable for the hair composition to have an appropriate pH. A pH that is too low or too high can damage the hair. For example, if the pH of the hair composition is too high, the hair will swell significantly, and the components that have penetrated the hair will easily disappear.

[0032] The hair composition according to this embodiment may be used in combination with another hair composition containing an oxidizing agent. In this configuration, the hair composition according to this embodiment is included in the first component of the hair treatment agent. The second component of the hair treatment agent contains the hair composition containing an oxidizing agent. The oxidizing agent is used to regenerate the disulfide bonds that have been broken by the reducing agent. Although the use of an oxidizing agent is not essential, the repair of disulfide bonds by the oxidizing agent can make the hair modification by the hair composition according to this embodiment more durable.

[0033] The following describes the components of the hair composition.

[0034] • Ingredient (A) Component (A) is at least one selected from the group consisting of hydrolyzed proteins, amino acids, and their derivatives. Hydrolyzed proteins are peptide compounds obtained by hydrolyzing proteins. Hydrolyzed proteins are, for example, hydrolyzed proteins (PPTs) of naturally derived proteins. Examples of hydrolyzed proteins include hydrolyzed keratin, hydrolyzed silk, hydrolyzed almond protein, hydrolyzed casein, hydrolyzed oat protein, hydrolyzed yeast protein, hydrolyzed collagen, hydrolyzed conchiolin, hydrolyzed white lupin protein, hydrolyzed soy protein, hydrolyzed pea protein, hydrolyzed corn protein, hydrolyzed milk protein, hydrolyzed honey protein, hydrolyzed hazelnut protein, hydrolyzed jojoba protein, hydrolyzed vegetable protein, hydrolyzed royal jelly protein, hydrolyzed wheat protein, and hydrolyzed rice protein. Only one of these hydrolyzed proteins may be used, or two or more may be used in combination.

[0035] Examples of amino acids and amino acid derivatives include glutamic acid, aspartic acid, glycine, serine, arginine, methionine, trimethylglycine, sodium polyaspartate, sodium dilauroyl glutamate lysine, N-lauroyl-L-lysine, dihydroxypropylarginine HCl, and PPG-2 arginine.

[0036] Hydrolyzed protein derivatives refer to proteins that have been chemically modified, such as through silylation, acylation, or cationization, after being hydrolyzed. Examples of silylated hydrolyzed proteins include (dihydroxymethylsilylpropoxy)hydroxypropyl hydrolyzed silk, (dihydroxymethylsilylpropoxy)hydroxypropyl hydrolyzed soy protein, (dihydroxymethylsilylpropoxy)hydroxypropyl hydrolyzed wheat protein, (dihydroxymethylsilylpropoxy)hydroxypropyl hydrolyzed collagen, hydrolyzed sesame protein PG-propylmethylsilanediol, and (dihydroxymethylsilylpropoxy)hydroxypropyl hydrolyzed keratin. Examples of acylated hydrolyzed proteins include lauroyl hydrolyzed silk, isostearoyl hydrolyzed silk, cocoyl hydrolyzed soy protein, palmitoyl hydrolyzed wheat protein, cocoyl hydrolyzed collagen, undecylenoyl hydrolyzed collagen, isostearoyl hydrolyzed collagen, and rosin hydrolyzed collagen. Examples of cationized hydrolyzed proteins include hydroxypropyltrimonium hydrolyzed silk, cocodimonium hydroxypropyl hydrolyzed silk, hydroxypropyltrimonium hydrolyzed wheat protein, cocodimonium hydroxypropyl hydrolyzed wheat protein, hydroxypropyltrimonium hydrolyzed collagen, cocodimonium hydroxypropyl hydrolyzed collagen, hydroxypropyltrimonium hydrolyzed casein, cationized hydrolyzed conchiolin, and hydroxypropyltrimonium hydrolyzed keratin. Only one of these hydrolyzed protein derivatives may be used, or two or more may be used in combination.

[0037] Component (A) may contain component (A1). Component (A1) is at least one selected from the group consisting of reduced hydrolyzed proteins and their derivatives. Reduced hydrolyzed proteins are proteins having cysteine ​​residues obtained by reducing the disulfide bonds contained in hydrolyzed proteins. The meaning of derivative is as explained above for hydrolyzed protein derivatives. Due to the cysteine ​​residues in component (A1), a hair composition containing component (A1) is able to cleave the disulfide bonds of hair through the reducing action of component (A1).

[0038] The hair composition according to this embodiment may contain, as component (A), at least one selected from the group consisting of hydrolyzed proteins and their derivatives. Alternatively, component (A) may be at least one selected from the group consisting of hydrolyzed proteins other than reduced hydrolyzed proteins and their derivatives, or at least one selected from the group consisting of amino acids and their derivatives. Component (A) may be a component other than component (A1) (hereinafter referred to as component (A2)).

[0039] Furthermore, if the hair composition contains component (A1), the hair composition may or may not contain component (C), i.e., a reducing agent. "Substantially not containing" means that trace amounts are permitted, and that the concentration of the reducing agent is less than 2% by mass, moreover less than 1% by mass, and especially less than 0.5% by mass, relative to the total mass of the hair composition.

[0040] A preferred example of a reduced hydrolyzed protein is reduced hydrolyzed keratin. Reduced hydrolyzed keratin can contain many cysteine ​​residues. Therefore, if component (A1) is reduced hydrolyzed keratin, the desired effect is more likely to be reliably obtained. Note that in reduced hydrolyzed keratin, it is not necessary for all disulfide bonds contained in hydrolyzed keratin to be reduced; disulfide bonds may remain.

[0041] The molecular weight of component (A) is not particularly limited, but is preferably 250 or more, 300 or more, 400 or more, 600 or more, 800 or more, 1,000 or more, and even 5,000 or more, and may be 10,000 or more, and particularly 20,000 or more. The upper limit of the molecular weight of component (A) is not particularly limited, and may be 50,000, 45,000, 40,000, and even 35,000. When the molecular weight of component (A) is large, the effect of hair modification by the hair composition becomes more pronounced, and the persistence of that effect also improves. When component (A) corresponds to a hydrolyzed protein or polymer, its molecular weight is often expressed by the average molecular weight. In this case, the average molecular weight is considered as the molecular weight, and an appropriate component (A) should be selected based on the upper and lower limits of the preferred range described above. Either the number average molecular weight or the weight average molecular weight may be applied to the average molecular weight. However, if the choice between number-average molecular weight and weight-average molecular weight results in different results regarding whether the molecular weight falls within the preferred range (e.g., 10,000 to 50,000), the following shall apply: When component (A) is component (A1), the weight-average molecular weight shall be applied; when component (A) is component (A2), the number-average molecular weight shall be applied for determination.

[0042] The content of component (A) relative to the total mass of the hair composition is not limited to a specific value, and may be 0.1% to 50% by mass, 1% to 30% by mass, 3% to 20% by mass, 5% to 15% by mass, or even 5.5% to 15% by mass. If component (A) is component (A2), the content of component (A) relative to the total mass of the hair composition may be 1% to 8% by mass, or even 3% to 7% by mass. If component (A) is component (A1), the content of component (A) relative to the total mass of the hair composition may be 5% to 20% by mass, 5.5% to 20% by mass, 6% to 18% by mass, or even 8% to 15% by mass.

[0043] ·Component (B) Component (B) is a penetrating agent. The penetrating agent promotes the penetration of component (A) into the hair. The penetrating agent may penetrate into the hair.

[0044] Examples of penetrating agents (B) include amines, alcohols, and surfactants.

[0045] Examples of amines include urea, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, 2-amino-2-methyl-1-propanol, 2-aminobutanol, 2-amino-2-methyl-1,3-propanediol, and guanidine.

[0046] Examples of alcohols include lower alcohols, higher alcohols, and polyhydric alcohols. Examples of lower alcohols include ethanol and isopropanol. Isopropanol is preferably used as the lower alcohol. Examples of higher alcohols include lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, cetostearyl alcohol, and behenyl alcohol. Examples of polyhydric alcohols include ethylene glycol, propylene glycol, 1,3-butylene glycol, 1,4-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,6-hexanediol, neopentyl glycol, 1,8-octanediol, 1,10-decanediol, diethylene glycol, spiroglycol, propylene glycol, dipropylene glycol, glycerin, and diglycerin. Isopropanol, 1,3-butylene glycol, and glycerin can be used as alcohols.

[0047] Examples of surfactants include anionic surfactants and nonionic surfactants.

[0048] Examples of anionic surfactants include alkyl ether sulfates, alkyl sulfates, alkyl ether sulfate esters, alkenyl ether sulfates, alkenyl sulfates, olefin sulfonates, alkanesulfonates, saturated or unsaturated fatty acid salts, alkyl ether carboxylates, alkenyl ether carboxylates, α-sulfone fatty acid salts, phosphate monoester surfactants, phosphate diester surfactants, sulfosuccinates, N-acyl glutamic acid, N-acylmethyl taurate salts, alkyl sulfosuccinates, polyoxyethylene alkyl ether phosphates, and their derivatives. An example of alkyl ether sulfate esters is sodium polyoxyethylene lauryl ether sulfate. Examples of alkyl sulfates are sodium lauryl sulfate and sodium cetyl sulfate. An example of a derivative of alkyl sulfate is sodium polyoxyethylene lauryl sulfate. An example of alkyl ether carboxylate is sodium laureth-4 carboxylate. An example of sulfosuccinate is disodium lauryl sulfosuccinate.

[0049] Examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene sorbitan fatty acid esters, sorbitan fatty acid esters, polyoxyethylene hydrogenated castor oil, alkyl glucosides, lipophilic glyceryl monostearate, and coconut oil fatty acid diethanolamide.

[0050] Component (B) may consist of only one of these compounds, or two or more may be used in combination. Component (B) may contain at least one selected from the group consisting of amines and alcohols, or both. Preferably, component (B) contains amines and alcohols. With such a configuration, the effect of modifying hair by the hair composition can be obtained more reliably, and the persistence of that effect can also be more reliably improved. Component (B) may contain only amines. Preferably, the amine is urea. Urea has the ability to denature proteins. Therefore, by bringing the hair composition into contact with hair, urea can denature the proteins in the hair. As a result, the hair composition can easily penetrate into the inside of the hair.

[0051] The molecular weight of component (B) is not limited to a specific value and may be 300 or more, or even 500 or more. Preferably, the molecular weight of component (B) is less than 300, less than 200, more than 100, and especially 80 or less.

[0052] The content of component (B) relative to the total mass of the hair composition is not limited to a specific value, and may be 0.1% to 50% by mass, 5% to 45% by mass, or even 10% to 40% by mass. If component (B) contains amines and alcohols, the content of amines relative to the total mass of the hair composition may be 1% or more by mass, 2% or more by mass, 3% or more by mass, 5% or more by mass, 5.5% or more by mass, 6% or more by mass, or even 8% or more by mass, or 45% or less by mass, 40% or less by mass, 35% or less by mass, or even 32% or less by mass. If component (B) contains amines and alcohols, the alcohol content relative to the total mass of the hair composition may be 1% by mass or more, 2% by mass or more, 3% by mass or more, 3.5% by mass or more, 5% by mass or more, 7% by mass or more, 8% by mass or more, or even 8.5% by mass or more, and may also be 30% by mass or less, 25% by mass or less, 20% by mass or less, 15% by mass or less, or even 12% by mass or less.

[0053] In a hair composition, the ratio of the content of component (B) to the content of component (A) is not limited to a specific value. The value is 0.1 to 30, 0.5 to 10, particularly greater than 1 and 10 or less, preferably greater than 1 and 7 or less, more preferably greater than 1 and 5 or less, even more preferably greater than 1 and 4.5 or less, and particularly preferably greater than 1 and 4.2 or less.

[0054] ·Component (C) Reducing agents act on the disulfide bonds in hair, promoting the penetration of component (A) into the hair. Alternatively, reducing agents may contribute to the hair composition having cysteine ​​residues by acting on the disulfide bonds contained in the hair composition. Examples of reducing agents include cysteines, ascorbic acid, ascorbates, sulfites, sulfites, pyrosulfites, and thiols. Examples of cysteines include L-cysteine, D-cysteine, DL-cysteine, N-acetylcysteine, L-cysteine ​​hydrochloride, and DL-cysteine ​​hydrochloride. Examples of ascorbic acid and ascorbates include L-ascorbic acid and sodium L-ascorbate. Examples of sulfites include sodium sulfite, potassium sulfite, ammonium sulfite, monoethanolamine sulfite, sodium bisulfite, and ammonium bisulfite. Examples of pyrosulfites include sodium pyrosulfite and potassium pyrosulfite. Examples of thiols include cysteamines, thiolactic acid, thioglycerin, butyrolactone thiol, and thioglycolates. Examples of cysteamines include cysteamine and cysteamine hydrochloride. Examples of thioglycolates include thioglycolic acid, sodium thioglycolate, ammonium thioglycolate, monoethanolamine thioglycolate, and esters of thioglycolic acid and glycerin. Component (C) may be one of these compounds selected individually, or two or more may be used in combination.

[0055] Preferred reducing agents include sulfites, sulfites, and pyrosulfites. These reducing agents can exhibit high reducing power in a weakly acidic to neutral range. As described later, the pH of the hair composition at 25°C is between 3.0 and 8.0, so the above-mentioned reducing agents can exert appropriate reducing power within this pH range. As a result, the hair composition can have high reducing power. In addition, by including the above-mentioned reducing agents in the hair composition, the hair composition can more reliably obtain the effect of modifying the medulla, and the persistence of that effect is also more reliably improved. Furthermore, by using the above-mentioned reducing agents, the hair composition can be maintained in a weakly acidic to neutral range, making it possible to reduce damage to other components of the hair, such as the cortex and cuticle.

[0056] The content of component (C) relative to the total mass of the hair composition is not limited to a specific value, and may be 0.1% to 15% by mass, 1% to 10% by mass, or even 2% to 8% by mass.

[0057] Other ingredients The hair composition may contain any ingredients other than those described above. These ingredients may be those found in known hair treatment agents.

[0058] The following may be appropriately included as optional ingredients: amphoteric surfactants, cationic surfactants, esters, higher fatty acids, oils and fats, fluorine compounds, silicones, UV absorbers, antioxidants, preservatives, plant extracts, amino acids, fragrances, essential oils, pigments, water, pH stabilizers, chelating agents, solvents, anti-inflammatory agents, and gelling agents.

[0059] However, in hair compositions, the content of cationic polymers is preferably, for example, less than 1% by mass, less than 0.5% by mass, and particularly less than 0.1% by mass. Cationic polymers may not be included at all. Polyquaternium-10 can be given as an example of a cationic polymer.

[0060] Next, we will describe the properties of the hair composition.

[0061] • Reducing power It is desirable that the hair composition has appropriate reducing power. Reducing power can be expressed, for example, by the amount of iodine that 1 g of the hair composition can reduce. More specifically, the amount of iodine that 1 g of the hair composition can reduce at 25°C can be expressed by the amount of 0.05 mol / L iodine solution. The amount of iodine to be reduced can be quantified using the iodine-starch reaction. Quantification can be performed by adding 0.05 mol / L iodine solution dropwise to a starch solution containing the hair composition at 25°C, measuring the amount of iodine solution used [mL] when the starch solution turns purple, and converting this amount to per 1 g of hair composition. The solution should be an aqueous solution.

[0062] The reducing power of the hair composition according to this embodiment is preferably 2.0 mL or more, 3.0 mL or more, 5.0 mL or more, 8.0 mL or more, 8.5 mL or more, and even 9.0 mL or more, expressed as the amount of 0.05 mol / L iodine solution reduced by 1 g of the hair composition. The upper limit of the reducing power is not limited to a specific value, but for example, 30 mL, 20 mL, 15 mL, 12 mL, and even 10 mL. When component (A) is component (A2), the reducing power is preferably 5.0 mL or more. On the other hand, when component (A) is component (A1), since the effect on hair is ensured even with a relatively small reducing power, the preferred reducing power is, for example, 2.0 mL or more, 3.0 mL or more, and even 3.5 mL or more.

[0063] • Pizza The pH of the hair composition at 25°C is 3.0 or higher and less than 8.0. From the viewpoint of suppressing damage to the hair, the pH of the hair composition may be 3.5 or higher, 4.0 or higher, 5.0 or higher, or even 6.0 or higher. From a similar viewpoint, the pH of the hair composition may be 7.8 or lower, 7.5 or lower, or in some cases less than 7.0. The preferred pH range is 4.0 to 7.5, particularly 5.0 or higher and less than 7.0. Within this pH range, the hair composition can have high reducing power. In addition, within this pH range, the hair composition can have high stability. In other words, by having an appropriate pH in the hair composition, the above-mentioned components (A) and / or (B) are less likely to precipitate.

[0064] When hair is damaged, the hair composition and hair components tend to leak out from inside the hair. In addition, when hair is damaged, it is difficult to maintain the effect of reducing the voids in the medulla. By controlling the pH to an appropriate range, the hair becomes less susceptible to damage, and the duration of the effect of modifying the medulla is improved. Conventional perming agents may have a high pH in order to improve reducing power. In this case, the hair is damaged. Specifically, according to the inventors' research, with conventional perming agents, the hair medulla can change into a black medulla. With the hair composition according to this embodiment, by controlling the pH to an appropriate range, the formation of a black medulla can be suppressed, and the effect of modifying the medulla can be obtained.

[0065] Next, we will describe the formulations of hair compositions and hair treatment agents containing hair compositions.

[0066] • Dosage form The dosage form of the hair composition is not particularly limited, and known dosage forms can be used. Preferred dosage forms are gel, solution, cream, aerosol, spray, or emulsion. The hair composition may be a one-component or two-component system. The hair composition may also be a multi-component system, such as a three-component system. The viscosity of the hair composition is not limited to a specific value. If the hair composition has an appropriate viscosity, it will not drip easily when applied to the hair and can be applied uniformly to the hair. Therefore, the effect of modifying the medulla can be obtained more reliably.

[0067] • Hair treatment The hair composition according to this embodiment may be used alone as a hair treatment agent, as an ingredient in various hair treatment agents, or as a hair treatment agent in combination with another composition. The hair treatment agent may be a novel agent that focuses on modifying the medulla, such as a medulla filler, or it may be a known hair treatment agent. Known hair treatment agents include, for example, shampoos, conditioners, hair rinses, hair dyes, permanent wave agents, hair waxes, hair creams, hair essences, hair lotions, hair sprays, and hair mousses. The hair treatment agent may be a non-washing hair treatment agent, such as a hair treatment like a conditioner or hair rinse. The hair treatment agent may be a hair modification agent, such as a permanent wave agent. The hair treatment agent may be a hair modifier used in combination with perm agents 1 and 2. The hair treatment agent may be various hair dyes, such as gray hair dyes, hair colors, or hair manicures. The hair composition according to this embodiment is also suitable for use as a pre-treatment agent for hair dyeing. This pre-treatment agent can improve color development.

[0068] • Second drug The hair treatment agent may comprise a first agent containing the hair composition according to this embodiment, and a second agent containing an oxidizing agent. Although the use of the second agent is not essential, using the second agent allows the components that have penetrated the inside of the hair to remain there for a longer period of time. The oxidizing agent contained in the second agent can act on the disulfide bonds of the hair. Specifically, the oxidizing agent can generate disulfide bonds and suppress the outflow of component (A) from inside the hair.

[0069] The oxidizing agent may be a known oxidizing agent. Examples of oxidizing agents include hydrogen peroxide, urea peroxide, melamine peroxide, sodium percarbonate, potassium percarbonate, alkali metal bromates, and alkali metal perates. Examples of alkali metal perates include perbromate, persulfate, and perborate. An example of alkali metal bromate is sodium bromate. The content of the oxidizing agent may be, for example, in the range of 1.0 to 9.0% by mass or in the range of 5.0 to 8.0% by mass relative to the total mass of the second agent.

[0070] The pH of the second agent should ideally be between 2.5 and 9.5, and especially between 5.0 and 7.0.

[0071] If the hair treatment agent is a multi-component formula, for example, it may consist of three or more treatment agents. In this case, the hair treatment agent includes one or more other treatment agents in addition to the first and second agents. The order in which the hair is treated with the first agent, the second agent, and one or more other treatment agents is not limited to a specific order; for example, the second agent may be used after the first agent. In the case of a three-component hair treatment agent, the third agent may be used before the hair treatment with the first agent, between the application of the first agent to the hair and the application of the second agent to the hair, and / or after the hair treatment with the second agent. In the case of a three-component hair treatment agent, the third agent may contain different components from the first and second agents.

[0072] Next, I will explain how to treat hair.

[0073] Hair treatment methods A hair treatment method according to one embodiment of the present invention includes bringing a hair composition according to the present invention into contact with hair, and maintaining contact between the hair composition and the hair until the voids in the hair medulla are reduced by the penetration of at least one component contained in the hair composition into the interior of the hair.

[0074] Another embodiment of the present invention is a hair treatment method comprising: contacting hair with a hair composition comprising at least one selected from the group consisting of hydrolyzed proteins, amino acids, and derivatives thereof; and maintaining contact between the hair composition and the hair until at least one component contained in the hair composition penetrates into the hair, thereby substantially filling the voids in the hair medulla.

[0075] Another embodiment of the present invention relates to a hair treatment method comprising contacting hair having a black medulla with a hair composition comprising at least one selected from the group consisting of hydrolyzed proteins, amino acids, and their derivatives, and maintaining contact between the hair composition and the hair until the black medulla changes into a white medulla.

[0076] The components and properties of the hair composition that can be used in these hair treatment methods (hereinafter referred to as the hair treatment method according to this embodiment) are as described above. The criteria for determining whether the medulla is substantially filled, the handling of molecular weights of hydrolyzed proteins, and the definitions of black medulla and white medulla are also as described above.

[0077] The method of applying the hair composition to the hair is not limited to a specific method; the hair composition may be applied directly to the hair by hand, or it may be applied to the hair using an application tool such as a comb, brush, paintbrush, or spray. The hair composition may be applied to dry hair or to wet hair. The temperature of the hair composition and the hair when applying the hair composition to the hair is not limited to a specific value, but a temperature of room temperature (25°C) or higher is appropriate, and 35°C or higher, 40°C or higher, and especially 45-60°C are more appropriate from the viewpoint of medulla filling. That is, it is preferable to bring the hair composition and the hair into contact when at least one temperature selected from the group consisting of the hair composition and the hair is above room temperature, for example, 35°C or higher. Specifically, this contact can be carried out by heating the hair composition to the above temperature, or by bringing it into contact with the hair together with water at the above temperature. This contact may be carried out by heating at least one selected from the group consisting of the hair composition and the hair, while maintaining contact between the hair composition and the hair, or more specifically, by heating the hair to which the hair composition has been applied to the above temperature.

[0078] Contact with a hair composition can cause the components of the hair composition to act on the hair medulla, potentially altering its structure. Typically, the components of the hair composition act directly and / or indirectly on the medulla, reducing its voids, modifying it, and in some cases becoming substantially filled.

[0079] It is preferable that the contact between the hair composition and the hair be maintained for a predetermined time sufficient to modify the medulla. Furthermore, the contact between the hair composition and the hair may be maintained at room temperature (25°C), or while the hair is heated. The duration of contact depends on factors such as the hair temperature, but may be, for example, 1 minute or more, 20 minutes or more, or in some cases, 1 hour or more. There is no particular upper limit to this time, but for example, it may be 24 hours or less. After the predetermined time has elapsed, the hair composition is removed. Removal of the hair composition can be carried out by rinsing with water or by washing the hair with a cleansing agent such as shampoo. This removal is not limited to the sole purpose of removing the hair composition. For example, the hair composition may be applied to the hair in the morning and removed by a normal hair wash performed that evening. Hair heating can be performed by heating the hair to room temperature (25°C) or higher, more specifically to 40°C or higher, and especially to 45-60°C, or by blowing air of this temperature range onto the hair. Hair heating can be performed, for example, using a hair dryer, hair iron, and far-infrared accelerator. Hair heating promotes the penetration of components of the hair composition into the hair.

[0080] The hair composition according to this embodiment is less likely to be washed out of the hair during the hair washing process. In other words, with the hair composition according to this embodiment, even after washing the hair, the medulla can maintain a state in which its voids are reduced, modified, and in some cases substantially filled.

[0081] The hair treatment method according to this embodiment reduces the voids in the medulla, preferably substantially filling the medulla, and in some cases changing the black medulla to a white medulla. This hair treatment method repairs the deepest part of the hair, and is particularly valuable as part of a treatment in hair salons.

[0082] The hair treatment method according to this embodiment may involve repeatedly bringing the hair composition into contact with the hair, maintaining contact between the hair composition and the hair, and removing the hair composition from the hair, in this order multiple times.

[0083] In the hair treatment method according to this embodiment, if the hair treatment agent is a two-part system, the method may include a step to remove the hair treatment agent between the hair treatment with the first agent and the hair treatment with the second agent, or the method may include a step to remove the second agent from the hair after the first agent has been brought into contact with the hair, without removing the first agent. After the second agent has been brought into contact with the hair, the method may include a step to remove the second agent, or it may not include a step to remove the second agent. As described above, the method to remove the first or second agent can be carried out, for example, by rinsing with water or by washing the hair with a cleansing agent such as shampoo. If the hair treatment agent is a multi-part system such as a three-part system, the method may include a step to remove the treatment agent before and / or after the hair treatment with each treatment agent, or it may not include a step to remove the treatment agent. [Examples]

[0084] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the following examples.

[0085] (Preparation of hair composition) Hair compositions according to the examples and comparative examples were prepared, each containing the following in the amounts shown in Tables 1 to 3: Component (A): reduced hydrolyzed keratin, hydrolyzed keratin, hydrolyzed pea protein, hydrolyzed sesame protein PG-propylmethylsilanediol, dilauroyl glutamate lysine sodium, or PPG-2 arginine; Component (B): urea, glycerin, 1,3-butylene glycol, or isopropanol; Component (C): sodium pyrosulfite. The pH of the hair compositions was adjusted to the desired value using NaOH or HCl. The pH of the hair compositions was measured at 25°C. In the "Component Name" column of the tables, (A) to (C) correspond to component (A), component (B), and component (C), respectively. All units in the tables are in mass%. The "-" notation in the "Component" column of each table means that the component is not contained.

[0086] (Evaluation of reducing power) Accurately weighing 1 g of the hair composition according to the examples and comparative examples, it was added to a 200 mL Erlenmeyer flask. To this, 100 mL of purified water conforming to cosmetic raw material standards (hereinafter simply referred to as "water") and 5 mL of 2.5% by mass sodium laureth sulfate aqueous solution were added to prepare the sample solution. The sample solution was thoroughly stirred. Next, 5 mL of 10% by mass sulfuric acid and 3 mL of 0.5% by mass starch solution were added to the sample solution and thoroughly stirred to prepare the evaluation solution. 0.05 mol / L iodine solution was added dropwise to the evaluation solution, and the titration volume of iodine solution when the evaluation solution turned purple was calculated. The titration volume of iodine solution per 1 g of hair composition [mL] was defined as an indicator of reducing power. The results are shown in Tables 1 to 3.

[0087] (Evaluation of reduction of medulla voids) Gray human hair samples were washed with a 5% by mass sodium laureth sulfate (SLS) aqueous solution, thoroughly rinsed with hot water, and then towel-dried. The hair compositions according to the examples and comparative examples were applied to the gray human hair samples, and left to stand at the temperatures and times shown in Tables 1-3. A Fine miniature incubator FF-12 manufactured by Tokyo Glass Instruments Co., Ltd. was used to heat the hair coated with the hair composition. After that, the gray human hair samples were rinsed with water. Next, the gray human hair samples were treated with a 7.5% by mass sodium bromate aqueous solution and left to stand at room temperature (25°C) for 10 minutes. After that, the gray human hair samples were rinsed with water again. After the gray human hair samples were air-dried, light was shone from the thickness direction of the gray human hair samples using an optical microscope manufactured by Keyence Corporation (digital microscope VHX-5000, magnification: 500x), and the light transmitted through the gray human hair samples was observed. A high-resolution zoom lens, the VH-Z500R, manufactured by Keyence Corporation, was used as the lens. The results are shown in Figures 1 to 11. The observation results of gray human hair before treatment are shown in Figure 12. Note that the gray human hair in Comparative Examples 3, 4, 6, 9, and 10 was observed using an optical microscope without applying natural drying.

[0088] (Sustained reduction of medulla voids) The persistence of the effect of reducing medulla voids in gray human hair treated with a hair composition was evaluated. In the gray human hair prepared as described above (evaluation of reduction of medulla voids), if a reduction in medulla voids was confirmed by optical microscope, and the reduction in medulla voids persisted even after washing the gray human hair with a 5% by mass SLS aqueous solution, it was evaluated as "◎". In the gray human hair prepared as described above (evaluation of reduction of medulla voids), if a reduction in medulla voids was confirmed by optical microscope, but the reduction in medulla voids was not substantially confirmed after washing the gray human hair with a 5% by mass SLS aqueous solution, it was evaluated as "○". In the above (evaluation of reduction of medulla voids), if a slight reduction in medulla voids was observed before air-drying of the gray human hair, but no reduction in medulla voids was observed after air-drying, it was evaluated as "△". In the above (evaluation of reduction of medulla voids), if no reduction in medulla voids was observed when the gray human hair was prepared, and no reduction in medulla voids was observed even after washing the gray human hair with a 5% by mass SLS aqueous solution, it was evaluated as "×".

[0089] (Evaluation of how noticeable gray hair is) The visibility of gray hairs in human hair treated as described above was visually evaluated. "◎" indicated that the hair was transparent and gray hairs were very inconspicuous, "〇" indicated that the hair was somewhat transparent and the white hairs were not very noticeable, "△" indicated that there was no change from before treatment, and "×" indicated that the white hairs were more noticeable than before treatment. The results are shown in Tables 1-3.

[0090] (Evaluation of hair texture) Hair bundles containing 10% gray human hair were washed with a 5% by mass aqueous solution of sodium laureth sulfate (SLS), thoroughly rinsed with hot water, and then towel-dried. The hair compositions according to the examples and comparative examples were applied to the hair bundles and reacted at the treatment temperatures and treatment times described in Tables 1-3. After that, the hair bundles were rinsed with water. Next, these hair bundles were treated with a 7.5% by mass aqueous solution of sodium bromate and left to stand at room temperature (25°C) for 10 minutes. After that, the hair bundles were rinsed with water again and air-dried. Ten professional evaluators evaluated the texture of the hair bundles on a scale of 1 to 5. For each evaluation item of hair bundle texture, a score of 5 was given for "very good," 4 for "good," 3 for "average," 2 for "not very good," and 1 for "bad." Regarding the texture of the hair strands, an average score of 4.0 or higher from 10 expert evaluators was rated as "◎", 3.0 or higher but less than 4.0 as "○", 2.0 or higher but less than 3.0 as "△", and 2.0 or lower as "×". The results are shown in Tables 1-3. Note that the texture of the hair strands refers to "shine", "firmness / body", and "cohesion".

[0091] In the table below, the average molecular weight is the weight-average molecular weight for reduced hydrolyzed keratin and the number-average molecular weight for all other types.

[0092] [Table 1]

[0093] [Table 2]

[0094] [Table 3]

[0095] In each example, the medulla voids were reduced, the medulla was substantially filled, and the black medulla changed to a white medulla (see Figures 1-4). On the other hand, in each comparative example, the medulla could not be sufficiently modified (see Figures 5-11). These medulla remained as black medulla. As shown in Figure 7, the hair composition according to Comparative Example 5 resulted in hair with a whitish core. Since the hair composition according to Comparative Example 5 is alkaline, the hair, especially the cuticle, was damaged, and it is thought that the hair composition penetrated into the inside of the hair. As a result, it is thought that hair with a whitish core was obtained. However, in the hair treated with the hair composition according to Comparative Example 5, light scattering on the surface of the hair increased, and gray hair was more noticeable than before treatment. In addition, with the hair composition according to Comparative Example 5, the hair is easily damaged, so the hair composition easily washes out of the hair, and the persistence of the effect of reducing the medulla voids is not sufficient. Therefore, it is difficult to say that the hair composition according to Comparative Example 5 modified the inside of the hair.

[0096] Next, the hair compositions of Example 2, Comparative Examples 3, 5, and 9 were used to evaluate their dyeability through hair coloring treatment and their ability to suppress frizz through straightening design treatment.

[0097] (Evaluation of dyeability after hair color treatment) A commercially available 50% gray hair mix hair bundle (10 cm long, 1 g, manufactured by Beaulux Co., Ltd.) was washed with a 5% by mass sodium laureth sulfate (SLS) aqueous solution, thoroughly rinsed with hot water, and then towel-dried. The hair bundle was reacted with the hair compositions according to Example 2, Comparative Example 3, and Comparative Example 9 at 50°C for 20 minutes. After that, the hair bundle was rinsed with water. Next, the hair bundle was treated with a 7.5% by mass sodium bromate aqueous solution and left to stand at room temperature (25°C) for 10 minutes. After that, the hair bundle was rinsed with water again and air-dried. Next, 4 g of basic hair dye ("Locol Indigo" manufactured by Takara Belmont Co., Ltd.) was applied to each hair bundle and left to stand at room temperature for 20 minutes. After that, the hair bundle was thoroughly rinsed with water and air-dried. Ten expert evaluators evaluated the dyeability (color intensity) of the hair bundle on a scale of 1 to 5. The dyeability of the hair strands was evaluated on a scale of 1 to 1: "Excellent" = 5, "Good" = 4, "Average" = 3, "Not very good" = 2, and "Poor" = 1. The average score of the 10 expert evaluators was evaluated as follows: "◎" if the average score was 4.0 or higher, "○" if it was between 3.0 and 4.0, "△" if it was between 2.0 and 3.0, and "×" if it was 2.0 or lower. The results are shown in Table 4.

[0098] (Evaluation of wave suppression by straight design treatment) Commercially available frizzy hair (20 cm long, 1.5 g, manufactured by INTERNATIONAL HAIR IMPORTERS & PRODUCTS) was washed with a 5% by mass sodium laureth sulfate (SLS) aqueous solution, rinsed thoroughly with hot water, and then towel-dried. The hair bundle was reacted with the hair compositions according to Example 2 and Comparative Example 5 at 50°C for 20 minutes. After that, the hair bundle was rinsed with water and dried with a hairdryer. Next, the hair bundle was clamped with a straight iron set to 180°C and moved from the root to the tip over a certain period of time, repeating this motion twice. Then, this hair bundle was treated with a 7.5% by mass sodium bromate aqueous solution and left to stand at room temperature (25°C) for 10 minutes. After that, the hair bundle was rinsed with water again and air-dried. Ten expert evaluators evaluated the frizz-suppressing effect of the hair bundle on a scale of 1 to 5. The effectiveness of suppressing hair strand frizz was evaluated on a scale of 1 to 1: "Excellent" = 5, "Good" = 4, "Average" = 3, "Not very good" = 2, and "Poor" = 1. The average score of 10 expert evaluators for suppressing hair strand frizz was evaluated as follows: "◎" if 4.0 or higher, "○" if 3.0 or higher but less than 4.0, "△" if 2.0 or higher but less than 3.0, and "×" if 2.0 or lower. The results are shown in Table 4.

[0099] [Table 4]

[0100] In Example 2, the hair strands were dyed well (Figure 13). On the other hand, in Comparative Examples 3 and 9, the dyeing performance of the hair strands was somewhat poor. Also, in Example 2, the frizz of the hair was well suppressed (Figure 14). On the other hand, in Comparative Example 5, the effect of suppressing the frizz of the hair strands was somewhat poor. It was found that the hair composition according to the present invention is excellent in dyeing performance by hair color treatment and in suppressing frizz by straight design treatment.

Claims

1. A hair treatment method comprising reducing the voids in the hair medulla by contacting the hair with a hair composition containing the following components (A) and (B), having a pH of 3.0 or higher and less than 8.0 at 25°C, The content of component (A) is 0.1% by mass or more and 50% by mass or less. The content of component (B) is 0.1% by mass or more and 50% by mass or less. Hair treatment methods. (A) At least one selected from the group consisting of reduced hydrolyzed proteins and their derivatives having a molecular weight of 10,000 or more and 50,000 or less, capable of acting as a reducing agent (provided that the derivative is a reduced hydrolyzed protein that has undergone at least one chemical modification selected from the group consisting of silylation, acylation, and cationization). (B) Penetrating agent

2. A hair treatment method comprising reducing the voids in the hair medulla by contacting the hair with a hair composition containing the following components (A) to (C) and having a pH of 5.0 or higher and less than 7.0 at 25°C, The content of component (A) is 0.1% by mass or more and 50% by mass or less. The content of component (B) is 0.1% by mass or more and 50% by mass or less. The content of the aforementioned component (C) is 0.1% by mass or more and 15% by mass or less. Hair treatment methods. (A) At least one selected from the group consisting of hydrolyzed proteins and derivatives thereof having a molecular weight of 20,000 or more and 40,000 or less (provided that the derivative is a hydrolyzed protein that has undergone at least one chemical modification selected from the group consisting of silylation, acylation, and cationization). (B) Penetrating agent containing urea (C) Reducing agent

3. A hair treatment method according to claim 1 or 2, further comprising maintaining contact between the hair composition and the hair until at least one component contained in the hair composition penetrates into the hair, thereby substantially filling the medulla of the hair.

4. The hair has a black medulla, A hair treatment method according to any one of claims 1 to 3, further comprising maintaining contact between the hair composition and the hair until the black medulla changes into a white medulla.

5. A hair treatment method according to any one of claims 1 to 4, comprising bringing the hair composition and the hair into contact at least one temperature selected from the group consisting of the hair composition and the hair, where the temperature is 35°C or higher.

6. A hair treatment method according to any one of claims 1 to 5, comprising heating at least one selected from the group consisting of the hair composition and the hair while maintaining contact between the hair composition and the hair.

7. The hair treatment method according to any one of claims 1 to 6, wherein the hair includes gray hair.

8. A hair composition for modifying the hair medulla, It contains the following ingredients (A) and (B): The pH at 25°C is 3.0 or higher and less than 8.

0. The content of component (A) is 0.1% by mass or more and 50% by mass or less. The content of component (B) is 0.1% by mass or more and 50% by mass or less. Composition for hair. (A) At least one selected from the group consisting of reduced hydrolyzed proteins and their derivatives having a molecular weight of 10,000 or more and 50,000 or less, capable of acting as a reducing agent (provided that the derivative is a reduced hydrolyzed protein that has undergone at least one chemical modification selected from the group consisting of silylation, acylation, and cationization). (B) Penetrating agent

9. A hair composition for modifying the hair medulla, It contains the following ingredients (A) to (C), The pH at 25°C is 5.0 or higher and less than 7.

0. The content of component (A) is 0.1% by mass or more and 50% by mass or less. The content of component (B) is 0.1% by mass or more and 50% by mass or less. The content of the aforementioned component (C) is 0.1% by mass or more and 15% by mass or less. Composition for hair. (A) At least one selected from the group consisting of hydrolyzed proteins and derivatives thereof having a molecular weight of 20,000 or more and 40,000 or less (provided that the derivative is a reduced hydrolyzed protein that has undergone at least one chemical modification selected from the group consisting of silylation, acylation, and cationization). (B) Penetrating agent containing urea (C) Reducing agent

10. The hair composition according to claim 8, wherein at 25°C, the amount of iodine reduced by 1 g of the hair composition is 2.0 mL or more, expressed as the amount of a 0.05 mol / L iodine solution.

11. The hair composition according to any one of claims 8 to 10, wherein at 25°C, the amount of iodine reduced by 1 g of the hair composition is 5.0 mL or more, expressed as the amount of a 0.05 mol / L iodine solution.

12. The hair composition according to any one of claims 8 to 11, wherein the content of component (A) relative to the total mass of the hair composition is 5% by mass or more to 15% by mass.

13. The hair composition according to claim 12, wherein the content of component (A) relative to the total mass of the hair composition is 5.5% by mass or more to 15% by mass.

14. A medulla filler comprising the hair composition described in any one of claims 8 to 13.

15. A gray hair treatment agent comprising the hair composition described in any one of claims 8 to 13.

16. A first agent comprising the hair composition according to any one of claims 8 to 13, A hair treatment agent comprising a second agent containing an oxidizing agent.

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