Method for treating fibers for head decorative products containing regenerated collagen fibers

Abstract

To provide a method for treating a fiber for a head decorative product, by which the underwater elastic modulus of the fiber for the head decorative product containing a regenerated collagen fiber can be improved, the color difference between the hair and the fiber for the head decorative product can be reduced, and the color compatibility can be improved.SOLUTION: A method for treating a fiber for a head decorative product containing a regenerated collagen fiber, wherein the regenerated collagen fiber contains a modified regenerated collagen fiber containing a predetermined component (X), and the method comprises a step (I) of adding a compound (A) having a pKa value of 1 or more and 7 or less and water to the fiber for a head decorative product, A method for treating a fiber for a head decorative product, comprising a step of applying a treatment agent composition A having a pH of 2 or more and 6 or less, a step (II) of attaching a head decorative product containing the fiber for a head decorative product to hair dyed with a hair dye B, and a step (III) of subjecting the hair and the fiber for a head decorative product to a wet state in a state where the hair and the fiber for a head decorative product are in contact with each other, wherein the method comprises the step (III) after the step (I) and the step (II).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for treating fibers for headwear products containing regenerated collagen fibers. [Background technology]

[0002] Modifiers have been studied for improving the texture, mechanical properties, etc. of fibers, hair, etc. For example, Patent Document 1 describes an elasticity-imparting agent that imparts elasticity to fibers, hair, etc. and modifies them, and that contains at least one selected from a gallic acid derivative with a specific structure, proanthocyanidin, chlorogenic acid and its derivatives, phloresin, and tannic acid.

[0003] As a method for dyeing fibers, blended fibers containing cellulosic fibers and protein fibers are generally dyed with reactive dyes. For example, according to Patent Document 2, it is known that blended fibers containing rayon and wool can be dyed with reactive dyes to be a solid color with no pattern. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-314084 [Patent Document 2] Japanese Patent Application Publication No. 186580 / 1983 Summary of the Invention [Problem to be solved by the invention]

[0005] However, it has been found that when regenerated collagen fibers are treated with a modifier such as that disclosed in Patent Document 1, the elastic modulus in water actually decreases, and the fibers tend to break easily when wet. Furthermore, even in the case of blended fibers containing cellulosic fibers and protein fibers as disclosed in Patent Document 2, when blended fibers containing cellulosic fibers and regenerated protein fibers are dyed with reactive dyes, there is a problem that mottled shading occurs under normal dyeing conditions and a solid color cannot be obtained. The present inventors have found that this problem (the occurrence of shading in dyeing) also occurs when dyeing hair and regenerated collagen fibers.

[0006] The present invention relates to a method for treating fibers for head accessories, which can improve the underwater elastic modulus of fibers for head accessories containing regenerated collagen fibers, reduce the color difference between hair and the fibers for head accessories, and improve the color matching effect. [Means for solving the problem]

[0007] The present inventors have found that the above problems can be solved by a processing method having certain steps, and have thus completed the present invention. That is, the present invention relates to the following. [1] A method for treating fibers for headwear products containing regenerated collagen fibers, comprising: The regenerated collagen fibers contain the following component (X): (X) A copolymer containing a structural unit derived from an unsaturated monomer having a carboxy group and a structural unit derived from an aromatic vinyl compound, the copolymer having an acid value of 100 mgKOH / g or more and a weight average molecular weight of 1500 or more and 15000 or less, or a salt thereof. The modified regenerated collagen fiber contains The method comprises the following steps (I) to (III): A method for treating fibers for head accessories, comprising the following step (III) after the steps (I) and (II). Step (I): A step of applying a treatment composition A containing a compound (A) having a pKa value of 1 or more and 7 or less and water and having a pH of 2 or more and 6 or less to the fiber for headwear. Step (II) A step of attaching a head accessory containing the fiber for a head accessory to hair dyed with hair dye B. Step (III): A step of keeping the hair and the fiber for head accessories in a wet state while the hair and the fiber for head accessories are in contact with each other. [2] A head accessory fiber treatment kit comprising a treatment composition A for treating head accessory fibers containing regenerated collagen fibers and a hair dye B for dyeing hair, The treatment composition A contains a compound (A) having a pKa value of 1 or more and 7 or less, and water, and has a pH of 2 or more and 6 or less, The regenerated collagen fiber is a fiber treatment kit for head accessories, which contains modified regenerated collagen fiber containing the following component (X): (X) A copolymer containing a structural unit derived from an unsaturated monomer having a carboxy group and a structural unit derived from an aromatic vinyl compound, the copolymer having an acid value of 100 mgKOH / g or more and a weight average molecular weight of 1500 or more and 15000 or less, or a salt thereof. [Effects of the Invention]

[0008] According to the present invention, a method for treating fibers for head accessories can be provided that improves the underwater elastic modulus of fibers for head accessories containing specific modified regenerated collagen fibers, making them less likely to break even when wet, and that reduces the color difference between hair and the fibers for head accessories, improving the color matching effect. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Definition] As used herein, the term "elastic modulus of regenerated collagen fibers in water" refers to the tensile modulus of regenerated collagen fibers in water at 20° C. Specifically, the tensile modulus can be evaluated by the method described in the Examples. In this specification, "reducing the color difference between the hair and the fiber for head accessories (including regenerated collagen fibers) and improving the color matching effect" means that the color difference between the hair and the fiber for head accessories is reduced after step (III) defined in the present invention, which is a step of bringing the hair and the fiber for head accessories into a wet state while the hair and the fiber for head accessories are in contact with each other, compared to before the step (III). This effect can be specifically evaluated by the method described in the examples.

[0010] [Method for treating fibers for headwear products] The method for treating fibers for head accessories of the present invention (hereinafter also simply referred to as "the method of the present invention") is a method for treating fibers for head accessories containing regenerated collagen fibers, comprising: The regenerated collagen fibers contain the following component (X): (X) A copolymer containing a structural unit derived from an unsaturated monomer having a carboxy group and a structural unit derived from an aromatic vinyl compound, the copolymer having an acid value of 100 mgKOH / g or more and a weight average molecular weight of 1500 or more and 15000 or less, or a salt thereof. The modified regenerated collagen fiber contains The method comprises the following steps (I) to (III): The method includes the following step (III) after the steps (I) and (II). Step (I): A step of applying a treatment composition A containing a compound (A) having a pKa value of 1 or more and 7 or less and water and having a pH of 2 or more and 6 or less to the fiber for headwear. Step (II) A step of attaching a head accessory containing the fiber for a head accessory to hair dyed with hair dye B. Step (III): A step of keeping the hair and the fiber for head accessories in a wet state while the hair and the fiber for head accessories are in contact with each other. The method of the present invention, having the above-described configuration, improves the underwater elastic modulus of fibers for head accessories containing specific modified regenerated collagen fibers, while also reducing the color difference between hair and the fibers for head accessories, thereby improving the color matching effect.

[0011] The reason why the method of the present invention exhibits the above-mentioned effects is not clear, but is presumed to be as follows. The fibers for head accessories to which the method of the present invention is applied are regenerated collagen fibers containing modified regenerated collagen fibers (hereinafter simply referred to as "modified regenerated collagen fibers") containing the component (X). Component (X) acts as a modifier for the regenerated collagen fibers, improving their water resistance, strength, etc. Modified regenerated collagen fibers containing component (X) have carboxyl groups inside the fibers. Under low pH conditions, the proportion of undissociated (acidic) carboxyl groups increases, and this is thought to improve the hydrophobicity of the fibers compared to when the proportion of dissociated (carboxy ion) carboxyl groups is high, resulting in an improved underwater elastic modulus. Here, the treatment composition used in step (I) of the present invention has a pH of 2 or more and 6 or less, and the compound (A) contained in the treatment composition has a pKa value of 1 or more and 7 or less. In a treatment agent with a pH of 2 or more and 6 or less, compound (A) having the above pKa value exhibits buffering ability, and therefore, by treating modified regenerated collagen fibers with the treatment composition, it is thought that the pH inside the fibers can be effectively lowered and the proportion of undissociated (acid type) carboxy groups can be increased in the structural portion derived from component (X) inside the fibers.

[0012] Furthermore, for example, when a head accessory is attached to a portion of the hair, the hair and the modified regenerated collagen fibers have different colors, and even if the hair and the modified regenerated collagen fibers are dyed with the same dye, they will dye differently. However, by using the method of the present invention, in step (III), the dye transfers from the hair dyed with hair dye B to the head accessory fiber containing the modified regenerated collagen fiber, which is thought to reduce the color difference between the hair and the head accessory fiber and improve color matching. The mechanism of action of the present invention is not limited to the above.

[0013] <Headdress products> In this specification, the term "headwear product" refers to, for example, a hair wig, a toupee, a weaving, a hair extension, a braided hair, a hair accessory, a doll hair, etc. Among these, from the viewpoint of effectively exerting the effects of the present invention, the headwear product used in the present invention preferably includes one or more selected from the group consisting of a hair wig, a toupee, a weaving, and a hair extension, and more preferably includes a hair extension. The term "fiber for head accessories" refers to fibers used in the above-mentioned head accessories, and includes human hair. The head accessory product in this specification may contain at least a portion of modified regenerated collagen fiber as the fiber for the head accessory product, but from the viewpoint of effectively obtaining the effects of the present invention, it is preferable that the fiber for the head accessory product consists solely of modified regenerated collagen fiber.

[0014] <Modified regenerated collagen fiber> The fibers for head accessories to be treated by the method of the present invention include regenerated collagen fibers, which include modified regenerated collagen fibers containing the following component (X): (X) A copolymer containing a structural unit derived from an unsaturated monomer having a carboxy group and a structural unit derived from an aromatic vinyl compound, the copolymer having an acid value of 100 mgKOH / g or more and a weight average molecular weight of 1500 or more and 15000 or less, or a salt thereof.

[0015] (Component (X)) Component (X) is a modifier for regenerated collagen fibers. The regenerated collagen fibers that are the target of modification by component (X) will be described later. Component (X) is a copolymer containing structural units derived from an unsaturated monomer having a carboxy group and structural units derived from an aromatic vinyl compound, and is a copolymer or a salt thereof having an acid value of 100 mgKOH / g or more and a weight average molecular weight of 1,500 or more and 15,000 or less. In component (X), the structural unit derived from an unsaturated monomer having a carboxy group may be derived from an unsaturated monocarboxylic acid, an unsaturated dicarboxylic acid, or a combination thereof. Specific examples of the unsaturated monomer having a carboxy group include unsaturated monocarboxylic acids and unsaturated dicarboxylic acids. Examples of unsaturated monocarboxylic acids include acrylic acid, methacrylic acid, crotonic acid, oleic acid, and cyclopentenylacetic acid, and examples of unsaturated dicarboxylic acids include maleic acid, fumaric acid, citraconic acid, mesaconic acid, itaconic acid, and methylene succinic acid. Alternatively, an unsaturated dicarboxylic acid anhydride may be used as the unsaturated monomer having a carboxy group, and may be converted into an acid form by hydrolysis with an alkali, etc. Examples of unsaturated dicarboxylic acid anhydrides include maleic anhydride and citraconic anhydride. The unsaturated monomers having a carboxy group can be used alone or in combination of two or more kinds.

[0016] The structural unit derived from an aromatic vinyl compound in component (X) is not particularly limited as long as it is derived from an aromatic compound substituted with at least a vinyl group. Specific examples of aromatic vinyl compounds include styrene, α-methylstyrene, p-methylstyrene, 3-vinyltoluene, dimethylstyrene, ethylvinylbenzene, chloromethylstyrene, vinylnaphthalene, and vinylanthracene. The aromatic vinyl compounds can be used alone or in combination of two or more kinds.

[0017] In component (X), the bonding state of the monomers that give each structural unit may be block bonding, random bonding, or a combination thereof.

[0018] Component (X) may contain structural units other than the above unsaturated monomers. Examples of other structural units include, but are not limited to, structural units derived from unsaturated aliphatic hydrocarbon compounds, such as linear, branched, or cyclic unsaturated aliphatic hydrocarbon compounds. Examples of the linear or branched unsaturated aliphatic hydrocarbon compound include propylene, isobutylene, diisobutylene, triisobutylene, tripropylene, and tetrapropylene. Examples of the cyclic unsaturated aliphatic hydrocarbon compound include cyclopentene, cyclohexene, and cyclooctene. The structural units derived from the unsaturated aliphatic hydrocarbon compound may include one or more types.

[0019] A suitable embodiment of component (X) is, for example, a copolymer containing structural units derived from one or more selected from the group consisting of unsaturated monocarboxylic acids and unsaturated dicarboxylic acids, and structural units derived from an aromatic vinyl compound. Specific examples of component (X), from the viewpoint of improving the modulus of elasticity in water and improving the color matching effect, preferably include at least one selected from the group consisting of styrene-maleic acid copolymer, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, vinylbenzoic acid-maleic acid copolymer, vinylbenzoic acid-acrylic acid copolymer, vinylbenzoic acid-methacrylic acid copolymer, and styrene-4-vinylbenzoic acid copolymer, and more preferably include styrene-maleic acid copolymer.

[0020] In component (X), the molar ratio (u1 / u2) of the structural unit (u1) derived from the unsaturated monomer having a carboxy group to the structural unit (u2) derived from the aromatic vinyl compound monomer is preferably 1 / 5 to 5 / 1, more preferably 1 / 3 to 3 / 1, and even more preferably 1 / 2 to 2 / 1.

[0021] The acid value of component (X) is 100 mgKOH / g or more, and from the viewpoint of improving the underwater elastic modulus and the color matching effect, it is preferably 200 mgKOH / g or more, more preferably 300 mgKOH / g or more, even more preferably 400 mgKOH / g or more, and preferably 1000 mgKOH / g or less, more preferably 800 mgKOH / g or less, even more preferably 600 mgKOH / g or less. The acid value of component (X) is preferably 100 mgKOH / g or more and 1000 mgKOH / g or less, more preferably 200 mgKOH / g or more and 800 mgKOH / g or less, even more preferably 200 mgKOH / g or more and 600 mgKOH / g or less, even more preferably 300 mgKOH / g or more and 600 mgKOH / g or less, even more preferably 400 mgKOH / g or more and 600 mgKOH / g or less. Here, the acid value refers to the number of milligrams of potassium hydroxide required to neutralize 1 g of sample.

[0022] Specific examples of component (X) having an acid value within the above range include the following compounds. Styrene-maleic acid copolymer (Styrene / maleic acid (molar ratio) = 1 / 1) 475mgKOH / g Styrene-maleic acid copolymer (Styrene / maleic acid (molar ratio) = 2 / 1) 355mgKOH / g Styrene-maleic acid copolymer (Styrene / maleic acid (molar ratio) = 3 / 1) 285mgKOH / g

[0023] Component (X) has a weight-average molecular weight of 1,500 or more and 15,000 or less, and from the viewpoint of improving the underwater elastic modulus and improving the color matching effect, it is preferably 3,000 or more, more preferably 5,000 or more, even more preferably 6,000 or more, and preferably 10,000 or less, more preferably 9,500 or less, and even more preferably 9,000 or less. The weight-average molecular weight of component (X) is preferably 1,500 or more and 10,000 or less, more preferably 3,000 or more and 10,000 or less, even more preferably 5,000 or more and 9,500 or less, and even more preferably 6,000 or more and 9,000 or less. The weight-average molecular weight of component (B) may be preferably 3,000 or more and 15,000 or less, more preferably 5,000 or more and 15,000 or less, even more preferably 6,000 or more and 10,000 or less. In this specification, the term "weight average molecular weight" refers to a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC), and specifically can be measured by the method described in the examples.

[0024] (Content of component (X)) From the viewpoint of improving the underwater elastic modulus and improving the color matching effect, the content of component (X) in the modified regenerated collagen fibers is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1.0% by mass or more, still more preferably 3.0% by mass or more, still more preferably 5.0% by mass or more, still more preferably 10% by mass or more, still more preferably 15% by mass or more, still more preferably 20% by mass or more, and is preferably 70% by mass or less, more preferably 65% ​​by mass or less, still more preferably 60% by mass or less, still more preferably 55% by mass or less, still more preferably 50% by mass or less, still more preferably 45% by mass or less, and still more preferably 40% by mass or less. The content of component (X) in the modified regenerated collagen fibers is preferably 0.1% by mass or more and 70% by mass or less, more preferably 0.5% by mass or more and 65% by mass or less, even more preferably 1.0% by mass or more and 60% by mass or less, even more preferably 3.0% by mass or more and 55% by mass or less, even more preferably 5.0% by mass or more and 50% by mass or less, even more preferably 10% by mass or more and 45% by mass or less, even more preferably 15% by mass or more and 40% by mass or less, and even more preferably 20% by mass or more and 40% by mass or less.

[0025] Furthermore, in this specification, the amount of component (X) in the modified regenerated collagen fibers is quantified by selecting an appropriate method that does not decompose component (X) and can dissolve the regenerated collagen fibers, and then dissolving and extracting the fibers. After appropriately diluting the extracted solution, the peak area of ​​a chromatogram plotted at an absorption wavelength suitable for quantifying component (X) is measured using, for example, GPC / UV, and the content of component (X) is calculated from the peak area. Specifically, the measurement can be performed using the method described in the Examples.

[0026] (Component (Y): Polyvalent metal, its salt, or its complex) In order to improve the underwater elastic modulus and color compatibility by firmly coordinating the component (X) inside the fiber, the modified regenerated collagen fiber preferably further contains a polyvalent metal, a salt thereof, or a complex thereof as component (Y) in addition to the component (X). Component (Y) also acts as a modifier for the regenerated collagen fiber. Examples of component (Y) include one or more polyvalent metals selected from the group consisting of calcium, magnesium, strontium, barium, zinc, chromium, aluminum, titanium, zirconium, tin, lead, antimony, iron, and copper, or salts or complexes thereof, which may be used alone or in combination of two or more. Among the above, from the viewpoints of improving water resistance, improving the underwater elastic modulus, and improving the color matching effect, component (Y) preferably contains one or more polyvalent metals selected from the group consisting of aluminum, zirconium, and titanium, or a salt or complex thereof, and more preferably contains aluminum, or a salt or complex thereof.

[0027] When the modified regenerated collagen fibers contain component (Y), the content of component (Y) in the modified regenerated collagen fibers is, from the viewpoints of improving water resistance, improving the underwater elastic modulus, and improving color matching, preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1.0% by mass or more, still more preferably 2.0% by mass or more, and is preferably 40% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less, and still more preferably 10% by mass or less. The content of component (Y) in the modified regenerated collagen fibers is, in terms of the metal element content, preferably 0.1% by mass or more and 40% by mass or less, more preferably 0.5% by mass or more and 30% by mass or less, even more preferably 1.0% by mass or more and 20% by mass or less, and still more preferably 2.0% by mass or more and 10% by mass or less. The amount of component (Y) in the modified regenerated collagen fibers is quantified, for example, as follows: The modified regenerated collagen fibers are incinerated, alkali-fused, and dissolved in acid to prepare a solution. This solution is then appropriately diluted to prepare a measurement sample, and the amount of metal elements is quantified using an ICP atomic emission spectrometer. Specifically, the amount of the metal elements can be measured by the method described in the Examples.

[0028] (Method for manufacturing modified regenerated collagen fiber) The regenerated collagen fibers that are the raw material for modified regenerated collagen fibers do not need to be 100% collagen, and may contain natural or synthetic polymers or additives to improve quality. Furthermore, they may be post-processed regenerated collagen fibers. The preferred form of regenerated collagen fibers is filament. Filaments are generally taken out from bobbins or boxes.

[0029] Suitable regenerated collagen fibers are artificially produced fibers made from collagen-derived polymers and oligomers. Regenerated collagen fibers are typically produced by using a solubilized collagen raw material as a spinning dope, discharging this from a spinning nozzle into a coagulation bath to form fibers, and then drying the fibrous collagen in the final step. Regenerated collagen fibers before the drying step (hereinafter also referred to as "undried regenerated collagen fibers") can be produced by conventionally known methods. For example, undried regenerated collagen fibers can be obtained by discharging an aqueous collagen solution obtained by solubilizing insoluble collagen fibers made from the split hides of livestock animals through a spinning nozzle or slit, immersing the aqueous solution in an inorganic salt solution, and then recovering the fibers without drying. This method will be specifically described below.

[0030] The preferred collagen raw material for producing regenerated collagen fibers is split skin. Split skins are obtained from fresh split skins obtained by slaughtering livestock animals such as cows, or from salted raw hides. These split skins are mostly composed of insoluble collagen fibers, but they are used after removing the fleshy part that usually adheres to them in a mesh-like form, and removing the salt used to prevent spoilage and deterioration.

[0031] These insoluble collagen fibers contain impurities such as lipids (e.g., glycerides, phospholipids, and free fatty acids), glycoproteins, and proteins other than collagen (e.g., albumin). These impurities have a significant effect on spinning stability, quality (e.g., luster and strength / elongation), odor, and other factors during fiberization. Therefore, it is preferable to remove these impurities in advance by, for example, soaking in lime to hydrolyze the fat in the insoluble collagen fibers and loosen the collagen fibers, and then subjecting them to conventional leather treatments such as acid / alkali treatment, enzyme treatment, and solvent treatment.

[0032] The insoluble collagen thus treated is then subjected to a solubilization treatment to cleave the cross-linked peptide moieties. As a method for such solubilization, a commonly used known alkali solubilization method, an enzyme solubilization method, etc., can be used. Furthermore, the alkali solubilization method and the enzyme solubilization method may be used in combination.

[0033] When the alkali solubilization method is applied, it is preferable to neutralize with an acid such as hydrochloric acid. Note that, as an improved version of the conventional alkali solubilization method, for example, the method described in JP-B-46-15033 may be used.

[0034] The enzymatic solubilization method has the advantage of being able to obtain solubilized collagen with a uniform molecular weight, and is a method that can be suitably employed in the present invention. Examples of such enzymatic solubilization methods that can be employed include those described in Japanese Patent Publication Nos. 43-25829 and 43-27513.

[0035] If the collagen that has been solubilized in this way is further subjected to operations such as pH adjustment, salting out, water washing, and solvent treatment, it is possible to obtain regenerated collagen fibers with excellent quality, and therefore it is preferable to perform these treatments.

[0036] Solubilized collagen is dissolved in an acid such as hydrochloric acid, acetic acid, or lactic acid to obtain a collagen aqueous solution having a pH of 2 to 4.5 and a collagen concentration of 1% by mass or more, preferably 2% by mass or more, and 15% by mass or less, preferably 10% by mass or less. The collagen aqueous solution may be degassed under reduced pressure and stirred, or filtered to remove water-insoluble fine particles. Furthermore, the collagen aqueous solution may contain appropriate amounts of additives, such as stabilizers and water-soluble polymers, for purposes such as improving mechanical strength, water resistance, heat resistance, gloss, and spinnability, preventing coloration, and preserving properties.

[0037] The collagen aqueous solution is extruded through a spinning nozzle or a slit, for example, and immersed in an inorganic salt aqueous solution to obtain undried regenerated collagen fibers. Examples of the inorganic salt aqueous solution include aqueous solutions of water-soluble inorganic salts such as sodium sulfate, sodium chloride, and ammonium sulfate. Typically, the concentration of the inorganic salt in these inorganic salt aqueous solutions is adjusted to 10 to 40% by mass. The pH of the inorganic salt aqueous solution is preferably 2 or higher, more preferably 4 or higher, and preferably 13 or lower, more preferably 12 or lower. To adjust the pH, for example, metal salts such as sodium borate and sodium acetate, hydrochloric acid, boric acid, acetic acid, and sodium hydroxide can be used. When the pH of the inorganic salt aqueous solution is within the above range, the collagen peptide bonds are less susceptible to hydrolysis, making it easier to obtain the desired fibers. The temperature of the inorganic salt aqueous solution is not particularly limited, but is generally desirably 35°C or lower, since this prevents denaturation of soluble collagen, prevents a decrease in the strength of the spun fibers, and facilitates the production of stable threads. The lower limit of the temperature of the inorganic salt aqueous solution is not particularly limited, but can generally be adjusted appropriately depending on the solubility of the inorganic salt.

[0038] The undried regenerated collagen fibers may be pretreated (crosslinked) by immersing them in an epoxy compound or a solution thereof. The amount of the epoxy compound is preferably at least 0.1 equivalent, more preferably at least 0.5 equivalent, and even more preferably at least 1 equivalent, relative to the amount of amino groups in the regenerated collagen fibers that can react with the epoxy groups of the epoxy compound, as measured by amino acid analysis, and is preferably at most 500 equivalents, more preferably at most 100 equivalents, and even more preferably at most 50 equivalents. Having the amount of the epoxy compound within this range not only ensures a sufficient water-insolubilizing effect on the regenerated collagen fibers, but is also favorable from an industrial handleability and environmental standpoint.

[0039] The epoxy compound is used as is or dissolved in various solvents. Examples of solvents include water; alcohols such as methyl alcohol, ethyl alcohol, and isopropanol; ethers such as tetrahydrofuran and dioxane; halogenated organic solvents such as dichloromethane, chloroform, and carbon tetrachloride; and neutral organic solvents such as dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). These solvents may be used alone or in combination of two or more. When water is used as the solvent, an aqueous solution of an inorganic salt such as sodium sulfate, sodium chloride, or ammonium sulfate may be used as needed. Typically, the concentration of the inorganic salt in the aqueous solution is adjusted to 10 to 40% by mass. The pH of the aqueous solution may be adjusted with, for example, a metal salt such as sodium borate or sodium acetate, or hydrochloric acid, boric acid, acetic acid, or sodium hydroxide. In this case, the pH of the aqueous solution is preferably 6 or higher, more preferably 8 or higher, from the viewpoint of not slowing down the reaction between the epoxy groups of the epoxy compound and the amino groups of collagen and ensuring sufficient insolubilization in water. Furthermore, since the pH of an aqueous solution of an inorganic salt tends to decrease over time, a buffer may be used if necessary.

[0040] The temperature during treatment of undried regenerated collagen fibers with an epoxy compound is preferably 50°C or lower, from the viewpoints of preventing denaturation of the regenerated collagen fibers, preventing a decrease in the strength of the resulting fibers, and facilitating stable production of threads.

[0041] [Treatment with a fiber treatment agent containing component (Y)] Here, the modified regenerated collagen fiber used in the present invention preferably contains the above-mentioned component (Y) from the viewpoint of improving water resistance, and in producing the modified regenerated collagen fiber, it is preferable to treat the undried regenerated collagen fiber obtained by the above-mentioned method by the following method. First, undried regenerated collagen fibers are immersed in a fiber treatment agent containing component (Y). The fiber treatment agent containing component (Y) is preferably an aqueous solution containing a polyvalent metal salt or polyvalent metal complex corresponding to component (Y). The polyvalent metal salt or polyvalent metal complex preferably contains an aluminum salt or aluminum complex, more preferably contains an aluminum salt. The aluminum salt is preferably basic aluminum chloride or basic aluminum sulfate represented by the following formula: Al(OH) n Cl 3-n , or Al2(OH) 2n (SO4) 3-n [In the formula, n is 0.5 to 2.5] Specific examples of the aluminum salt include aluminum sulfate, aluminum chloride, and alum, and these can be used alone or in combination of two or more.

[0042] The content of the polyvalent metal salt and polyvalent metal complex in the fiber treatment agent is preferably 0.3 mass % or more and 5 mass % or less in terms of polyvalent metal oxide (aluminum oxide when the polyvalent metal is aluminum).

[0043] In order to prevent the polyvalent metal salt or polyvalent metal complex from being rapidly absorbed into the undried regenerated collagen fibers and causing uneven concentration, inorganic salts such as sodium chloride, sodium sulfate, and potassium chloride may be added to the fiber treatment agent as appropriate.

[0044] The pH of the fiber treatment agent at 25°C is preferably in the range of 2.5 or more and 5 or less, and can be adjusted using, for example, hydrochloric acid, sulfuric acid, acetic acid, sodium hydroxide, sodium carbonate, etc. A pH of 2.5 or more can suppress denaturation of the collagen structure, while a pH of 5 or less reduces the risk of precipitation of polyvalent metal salts or polyvalent metal complexes. It is preferable to initially adjust the pH to 2.2 or more and 3.5 or less to allow the aqueous solution of the polyvalent metal salt or polyvalent metal complex to sufficiently penetrate into the undried regenerated collagen fibers, and then add, for example, sodium hydroxide, sodium carbonate, etc. to adjust the pH to 3.5 or more and 5 or less to complete the treatment. When a highly basic polyvalent metal salt or polyvalent metal complex is used, only an initial pH adjustment of 2.5 or more and 5 or less is sufficient.

[0045] When treating with a fiber treatment agent containing component (Y), the bath ratio of undried regenerated collagen fibers to the fiber treatment agent (dry mass of undried regenerated collagen fibers:mass of the fiber treatment agent), when the mass of fibers after conditioning for 24 hours at 20°C and a relative humidity of 65%, is taken as the dry mass, is preferably 1:2 to 1:500, more preferably 1:3 to 1:250, even more preferably 1:5 to 1:100, and even more preferably 1:20 to 1:50.

[0046] In this step, the treatment conditions for the regenerated collagen fibers may be set using the mass ratio [(X) / (A)] of the compound (A) in the treatment composition A to the component (X) in the regenerated collagen fibers as an index. Specifically, for example, when treatment composition A is applied to regenerated collagen fibers, this step may be performed under conditions such that the mass ratio of compound (A) in treatment composition A to component (X) in the regenerated collagen fibers [(X) / (A)] is preferably 0.2 or more, more preferably 0.5 or more, even more preferably 0.6 or more, still more preferably 0.8 or more, still more preferably 1.0 or more, still more preferably 1.5 or more, and still more preferably 2.0 or more, from the viewpoint of improving penetration into the fibers and improving the treatment effect, and is preferably 2000 or less, more preferably 1000 or less, still more preferably 400 or less, still more preferably 200 or less, still more preferably 100 or less, still more preferably 50 or less, still more preferably 20 or less, still more preferably 10 or less, and still more preferably 7 or less. That is, the mass ratio [(X) / (A)] is preferably 0.2 or more and 2000 or less, more preferably 0.5 or more and 1000 or less, even more preferably 0.6 or more and 400 or less, still more preferably 0.8 or more and 200 or less, still more preferably 1.0 or more and 100 or less, still more preferably 1.5 or more and 50 or less, still more preferably 1.5 or more and 20 or less, still more preferably 2.0 or more and 10 or less, and still more preferably 2.0 or more and 7 or less. On the other hand, when the treatment composition A is immersed in the regenerated collagen fibers, this step may be carried out under conditions such that the mass ratio of the compound (A) in the treatment composition A to the component (X) in the regenerated collagen fibers [(X) / (A)] is preferably 0.01 or more, more preferably 0.02 or more, even more preferably 0.03 or more, still more preferably 0.05 or more, still more preferably 0.08 or more, and still more preferably 0.10 or more, from the viewpoint of improving penetration into the fibers and improving the treatment effect, and is preferably 150 or less, more preferably 100 or less, even more preferably 30 or less, still more preferably 15 or less, still more preferably 5 or less, still more preferably 3 or less, still more preferably 1.5 or less, still more preferably 1.0 or less, and still more preferably 0.5 or less. That is, the mass ratio [(X) / (A)] is preferably 0.01 or more and 150 or less, more preferably 0.02 or more and 100 or less, even more preferably 0.03 or more and 30 or less, still more preferably 0.03 or more and 15 or less, still more preferably 0.03 or more and 5 or less, still more preferably 0.05 or more and 3 or less, still more preferably 0.08 or more and 1.5 or less, still more preferably 0.10 or more and 1.0 or less, and still more preferably 0.10 or more and 0.5 or less.

[0047] Furthermore, the treatment conditions for the regenerated collagen fibers can also be set using the mass ratio [(Y) / (A)] of the compound (A) in the treatment composition A to the component (Y) in the regenerated collagen fibers as an index. Specifically, for example, when treatment composition A is applied to regenerated collagen fibers, this step can be carried out under conditions such that the mass ratio of compound (A) in treatment composition A to component (Y) in the regenerated collagen fibers [(Y) / (A)] is preferably 0.005 or more, more preferably 0.010 or more, even more preferably 0.02 or more, still more preferably 0.05 or more, and even more preferably 0.10 or more, from the viewpoint of improving penetration into the fibers and improving the treatment effect, and is preferably 100 or less, more preferably 20 or less, even more preferably 10 or less, still more preferably 5 or less, still more preferably 2 or less, still more preferably 1.0 or less, still more preferably 0.5 or less, and even more preferably 0.2 or less. That is, the mass ratio [(Y) / (A)] is preferably 0.005 or more and 100 or less, more preferably 0.010 or more and 20 or less, even more preferably 0.02 or more and 5 or less, even more preferably 0.05 or more and 2 or less, even more preferably 0.05 or more and 1.0 or less, even more preferably 0.10 or more and 0.5 or less, and even more preferably 0.10 or more and 0.2 or less. On the other hand, when the treatment composition A is immersed in the regenerated collagen fibers, this step can be carried out under conditions such that the mass ratio of the compound (A) in the treatment composition A to the component (Y) in the regenerated collagen fibers [(Y) / (A)] is preferably 0.001 or more, more preferably 0.003 or more, even more preferably 0.005 or more, still more preferably 0.010 or more, still more preferably 0.02 or more, still more preferably 0.03 or more, from the viewpoint of improving penetration into the fibers and improving the treatment effect, and is preferably 33 or less, more preferably 10 or less, still more preferably 7 or less, still more preferably 3 or less, still more preferably 1.0 or less, still more preferably 0.7 or less, still more preferably 0.3 or less, still more preferably 0.2 or less, still more preferably 0.1 or less. That is, the mass ratio [(Y) / (A)] is preferably 0.001 or more and 33 or less, more preferably 0.003 or more and 10 or less, even more preferably 0.005 or more and 7 or less, still more preferably 0.005 or more and 3 or less, still more preferably 0.005 or more and 1.0 or less, still more preferably 0.010 or more and 0.7 or less, still more preferably 0.02 or more and 0.3 or less, still more preferably 0.02 or more and 0.2 or less, and still more preferably 0.03 or more and 0.1 or less.

[0048] The temperature during treatment with the fiber treatment agent containing component (Y) (liquid temperature of the fiber treatment agent) is not particularly limited, but is preferably 5°C or higher, more preferably 10°C or higher, and is preferably 50°C or lower, more preferably 45°C or lower.

[0049] The treatment time (immersion time) with the fiber treatment agent containing component (Y) is preferably 15 minutes or more, more preferably 30 minutes or more, even more preferably 1 hour or more, and even more preferably 3 hours or more, and is preferably 48 hours or less, more preferably 33 hours or less, and even more preferably 20 hours or less.

[0050] After treating the undried regenerated collagen fibers with an epoxy compound and / or the fiber treatment agent, they may be washed with water, for example, by washing with running water for 10 minutes to 4 hours.

[0051] [Treatment with a fiber treatment agent containing component (X)] Regenerated collagen fibers, or undried regenerated collagen fibers obtained by treatment with a fiber treatment agent containing component (Y), are treated with a fiber treatment agent containing component (X) to obtain modified regenerated collagen fibers, which are the subject of the method of the present invention.

[0052] From the viewpoint of improving penetration into fibers and improving the treatment effect, the content of component (X) in the fiber treatment agent is preferably 0.3% by mass or more, more preferably 0.5% by mass or more, even more preferably 1.0% by mass or more, still more preferably 2.5% by mass or more, still more preferably 3.0% by mass or more, still more preferably 4.0% by mass or more, and is preferably 60% by mass or less, more preferably 40% by mass or less, still more preferably 35% by mass or less, still more preferably 30% by mass or less, still more preferably 20% by mass or less, still more preferably 10% by mass or less, and still more preferably 5% by mass or less. The content of component (X) in the fiber treatment agent is preferably 0.3% by mass or more and 60% by mass or less, more preferably 0.5% by mass or more and 60% by mass or less, even more preferably 1.0% by mass or more and 40% by mass or less, still more preferably 2.5% by mass or more and 40% by mass or less, still more preferably 3.0% by mass or more and 35% by mass or less, still more preferably 4.0% by mass or more and 30% by mass or less, still more preferably 4.0% by mass or more and 20% by mass or less, still more preferably 4.0% by mass or more and 10% by mass or less, and still more preferably 4.0% by mass or more and 5% by mass or less.

[0053] The fiber treating agent containing component (X) preferably further contains a pH adjuster. The pH adjuster is not particularly limited as long as it can adjust the pH to the desired level, and examples thereof include alkalis such as sodium hydroxide and potassium hydroxide, and acids such as phosphoric acid, sulfuric acid and hydrochloric acid.

[0054] The fiber treating agent containing component (X) further contains water. The water content in the fiber treating agent is preferably 40% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, and even more preferably 70% by mass or more, and is preferably 99.7% by mass or less.

[0055] The pH of the fiber treatment agent containing component (X) at 25°C is preferably 3.0 or higher, more preferably 3.5 or higher, and even more preferably 4.0 or higher, from the viewpoint of suppressing damage to the fiber, and is preferably 7.5 or lower, more preferably 7.0 or lower, and even more preferably 6.5 or lower, from the viewpoint of suppressing damage to the fiber. The pH of the fiber treatment agent containing component (X) at 25°C is preferably 3.0 or higher and 7.5 or lower, more preferably 3.5 or higher and 7.0 or lower, and even more preferably 4.0 or higher and 6.5 or lower. The pH can be measured by the method described in the Examples.

[0056] Treatment with a fiber treatment agent containing component (X) can be carried out by immersing regenerated collagen fibers, or undried regenerated collagen fibers obtained by treatment with a fiber treatment agent containing component (Y), in the fiber treatment agent containing component (X).

[0057] When treating with a fiber treatment agent containing component (X), the bath ratio of regenerated collagen fibers or undried regenerated collagen fibers to the fiber treatment agent (dry mass of regenerated collagen fibers or undried regenerated collagen fibers:mass of the fiber treatment agent) is preferably 1:2 to 1:500, more preferably 1:3 to 1:250, even more preferably 1:5 to 1:100, and even more preferably 1:20 to 1:50, when the mass of the fibers after conditioning at 20°C and a relative humidity of 65% for 24 hours is taken as the dry mass.

[0058] The temperature during treatment with a fiber treatment agent containing component (X) (the temperature of the fiber treatment agent) is preferably 20°C or higher, more preferably 25°C or higher, and even more preferably 30°C or higher, from the viewpoint of improving penetration into fibers, and from the viewpoint of suppressing damage to fibers, it is preferably less than 100°C, more preferably 90°C or lower, even more preferably 80°C or lower, still more preferably 70°C or lower, and even more preferably 60°C or lower. The temperature during treatment with a fiber treatment agent containing component (X) (the temperature of the fiber treatment agent) is preferably 20°C or higher and lower than 100°C, more preferably 20°C or higher and 90°C or lower, even more preferably 25°C or higher and 80°C or lower, still more preferably 25°C or higher and 70°C or lower, and even more preferably 30°C or higher and 60°C or lower. When treating with a heated fiber treatment agent, the regenerated collagen fibers or undried regenerated collagen fibers may be immersed in the heated fiber treatment agent, or the regenerated collagen fibers or undried regenerated collagen fibers may be immersed in a cold fiber treatment agent and then the fiber treatment agent may be heated.

[0059] The treatment time (immersion time) with the fiber treatment agent containing component (X) is preferably 15 minutes or more, more preferably 30 minutes or more, even more preferably 1 hour or more, and even more preferably 3 hours or more from the viewpoint of improving the treatment effect, and is preferably 48 hours or less, more preferably 33 hours or less, and even more preferably 20 hours or less from the viewpoint of suppressing damage to the fiber. The treatment time (immersion time) with the fiber treatment agent containing component (X) is preferably 15 minutes to 48 hours, more preferably 30 minutes to 33 hours, even more preferably 1 hour to 20 hours, and even more preferably 3 hours to 20 hours.

[0060] Treatment with the fiber treatment agent containing component (X) is preferably carried out in an environment in which evaporation of water is suppressed. Specific means for suppressing evaporation of water include covering the container of the fiber treatment agent in which the fibers are immersed with a film-like substance, cap, lid, or the like made of a material that is impermeable to water vapor.

[0061] After treatment with the fiber treatment agent, the resulting modified regenerated collagen fibers are preferably washed with water, for example, by washing with running water for 10 minutes to 4 hours.

[0062] The treatment with the fiber treatment agent containing component (X) may be carried out two or more times. Specifically, it is preferable to carry out the following steps (1) and (2) in this order two or more times. (1) A step of immersing regenerated collagen fibers or undried regenerated collagen fibers obtained by treatment with a fiber treatment agent containing component (Y) in a fiber treatment agent containing component (X). (2) A step of removing the fibers immersed in the fiber treatment agent in (1) and rinsing them with water.

[0063] From the viewpoint of improving the treatment effect, the treatment conditions for the first treatment and the second and subsequent treatments are more preferably within the following ranges, with the other points remaining the same as above. In the first treatment, the pH at 25°C of the fiber treatment agent used in step (1) is preferably 4.5 or higher, more preferably 5.0 or higher, and is preferably 7.5 or lower, more preferably 7.0 or lower, and even more preferably 6.5 or lower, from the viewpoints of improving penetration into the fiber and suppressing damage to the fiber. In the first treatment, the pH at 25°C of the fiber treatment agent used in step (1) is preferably 4.5 or higher and 7.5 or lower, more preferably 5.0 or higher and 7.0 or lower, and even more preferably 5.0 or higher and 6.5 or lower. In the first treatment, the treatment time (immersion time) in step (1) is preferably 3 hours or more, more preferably 4 hours or more, and even more preferably 6 hours or more from the viewpoint of improving the treatment effect, and is preferably 48 hours or less, more preferably 33 hours or less, and even more preferably 20 hours or less from the viewpoint of suppressing damage to the fiber. In the first treatment, the treatment time (immersion time) in step (1) is preferably 3 hours or more and 48 hours or less, more preferably 4 hours or more and 33 hours or less, and even more preferably 6 hours or more and 20 hours or less.

[0064] In the second or subsequent treatments, the pH at 25°C of the fiber treatment agent used in step (1) is preferably 3.0 or higher, more preferably 3.5 or higher, and is preferably 6.0 or lower, more preferably 5.5 or lower, even more preferably 5.0 or lower, and still more preferably less than 4.5, from the viewpoint of improving the treatment effect. In the second or subsequent treatments, the pH at 25°C of the fiber treatment agent used in step (1) is preferably 3.0 or higher and 6.0 or lower, more preferably 3.0 or higher and 5.5 or lower, even more preferably 3.5 or higher and 5.0 or lower, and still more preferably 3.5 or higher and lower than 4.5. In the second or subsequent treatments, the treatment time (immersion time) in step (1) is preferably 15 minutes or more, more preferably 30 minutes or more, from the viewpoint of improving the treatment effect, and is preferably 5 hours or less, more preferably 3 hours or less, and even more preferably 2 hours or less, from the viewpoint of suppressing damage to the fibers. In the second or subsequent treatments, the treatment time (immersion time) in step (1) is preferably 15 minutes or more and 5 hours or less, more preferably 15 minutes or more and 3 hours or less, and even more preferably 30 minutes or more and 2 hours or less.

[0065] From the viewpoint of improving the treatment effect and productivity, the number of treatments with the fiber treatment agent containing component (X) is preferably 2 or more, preferably 5 or less, more preferably 3 or less, and is preferably 2 to 5 times, more preferably 2 to 3 times. After the above treatment, the resulting modified regenerated collagen fibers are preferably dried. The drying temperature is preferably 40°C or higher, more preferably 50°C or higher, from the viewpoint of improving the drying rate, and is preferably 100°C or lower, more preferably 80°C or lower, from the viewpoint of suppressing damage to the fibers. The drying time is preferably 15 minutes or longer, more preferably 30 minutes or longer, and from the viewpoint of suppressing damage to the fibers, is preferably 48 hours or shorter, more preferably 33 hours or shorter, and even more preferably 20 hours or shorter.

[0066] The above modification treatment allows component (X) to penetrate into the regenerated collagen fibers. Furthermore, when treatment is performed with a fiber treatment agent containing component (Y), component (X) is strongly coordinated to polyvalent metals within the fibers. Applying the method of the present invention to fibers for head accessories containing the modified regenerated collagen fibers improves the underwater elastic modulus of the fibers, and the dye in hair dye B (described below) interacts with components (X) and (Y) to more easily remain within the modified regenerated collagen fibers, which is thought to further improve color compatibility.

[0067] The regenerated collagen fibers to which the method of the present invention is applied may be those that contain at least a portion of the modified regenerated collagen fibers, or may be fibers consisting solely of modified regenerated collagen fibers. From the viewpoint of improving the underwater elastic modulus and improving the color matching effect, the regenerated collagen fibers to which the method of the present invention is applied are preferably fibers consisting solely of modified regenerated collagen fibers.

[0068] The method of the present invention comprises the following steps (I) to (III), with step (III) following steps (I) and (II). Step (I): A step of applying a treatment composition A containing a compound (A) having a pKa value of 1 or more and 7 or less and water and having a pH of 2 or more and 6 or less to the fiber for headwear. Step (II) A step of attaching a head accessory containing the fiber for a head accessory to hair dyed with hair dye B. Step (III): A step of keeping the hair and the fiber for head accessories in a wet state while the hair and the fiber for head accessories are in contact with each other.

[0069] The fiber for head accessories subjected to steps (I) to (III) contains the modified regenerated collagen fiber. In step (III), the dye migrates from the hair dyed with hair dye B to the fiber for head accessories containing the modified regenerated collagen fiber, thereby dyeing the fiber for head accessories. This reduces the color difference between the hair and the fiber for head accessories, improving the color matching effect.

[0070] Here, the fiber for head accessories used in the method of the present invention may be colored or uncolored, but from the viewpoint of improving the color compatibility between the hair and the fiber for head accessories, it is preferable that the fiber be colored, for example, with a pigment.

[0071] The method of the present invention is either (1) a method having the steps (I), (II), and (III) in that order, or (2) a method having the steps (II), (I), and (III) in that order. In the method (1), step (I) is carried out before step (II). That is, treatment composition A is applied to fibers for head accessories (step (I)), and a head accessory containing the treated fibers for head accessories is obtained. The head accessory is then attached to hair dyed with hair dye B (step (II)), and the hair and the fibers for head accessories are then left in a wet state while in contact with each other (step (III)). A rinsing step or a washing step with a detergent may be included between steps (I) and (II), and a rinsing step is preferably included. In the method (2), step (I) is performed after step (II). That is, after attaching the head ornament containing the fiber for head ornaments to hair dyed with hair dye B (step (II)), treatment composition A is applied to the fiber for head ornaments without removing the head ornament containing the fiber for head ornaments (step (I)), thereby obtaining a head ornament containing dyed fiber for head ornaments. Next, the hair and the dyed fiber for head ornaments are kept in contact with each other and kept in a wet state (step (III)). In step (III) of applying treatment composition A to the head ornament containing the fiber for head ornaments, a conventional method such as wrapping the head ornament containing the fiber for head ornaments in aluminum foil, plastic wrap, or the like may be used. Among the above, the method (1) is preferred from the viewpoint of ease of processing.

[0072] <Process (I)> In step (I), the treatment composition A is applied to the fiber for head accessories. The fiber for head accessories contains regenerated collagen fibers including the modified regenerated collagen fibers.

[0073] (Treatment Composition A) Treatment composition A contains water and a compound (A) having a pKa value of 1 or more and 7 or less, and has a pH of 2 or more and 6 or less. Compound (A) is a compound other than component (X).

[0074] [Compound (A) having a pKa value of 1 or more and 7 or less] Compound (A) has a pKa of 1 or more and 7 or less. Here, pKa is the acid dissociation index at 25°C, and when compound (A) has multiple dissociation stages, the pKa of any stage may be 1 or more and 7 or less. The acid dissociation exponent pKa is the common logarithm of the reciprocal of the acid dissociation constant (Ka), -logKa, and is a value described in the Chemical Handbook, Basics II, 4th Revised Edition, edited by the Chemical Society of Japan (published by Maruzen Co., Ltd.). If the value is not described in the literature, it can be determined using a commercially available pH meter (such as F-23, manufactured by Horiba Ltd., temperature: 25°C) according to the method described in F.R. Hartley, C. Burgess, and R.M. Alcock, "Solution Equilibria," John Wilery (1980).

[0075] From the viewpoint of improving the modulus of elasticity in water of the modified regenerated collagen fibers, the pKa of compound (A) is from 1 to 7, preferably from 1.5 or more, more preferably from 2.0 or more, even more preferably from 2.5 or more, and preferably from 6 to 5, more preferably from 4 to 4. The pKa of compound (A) is from 1 to 7, preferably from 1.5 to 6, more preferably from 2.0 to 5, even more preferably from 2.5 to 4.

[0076] From the viewpoint of improving the elastic modulus in water of the modified regenerated collagen fibers, the pKa of compound (A) is preferably −3.0 or more, more preferably −2.0 or more, even more preferably −1.0 or more, and preferably +3.0 or less, more preferably +2.0 or less, even more preferably +1.0 or less, relative to the pH value of treatment composition A. The pKa of compound (A) is preferably −3.0 or more and +3.0 or less, more preferably −2.0 or more and +2.0 or less, even more preferably −1.0 or more and +1.0 or less, relative to the pH value of treatment composition A.

[0077] From the viewpoint of enabling the preparation of a highly concentrated treatment composition with high buffer capacity and further improving the modulus of elasticity in water of the modified regenerated collagen fibers after treatment, compound (A) has a solubility of preferably 1 g or more, more preferably 2.5 g or more, even more preferably 5.0 g or more, and even more preferably 10 g or more in 100 g of water at 25°C at pH 3. There is no particular upper limit to the solubility, but it is preferably 100 g or less. Here, the solubility in 100 g of water at 25°C at pH 3 refers to the solubility in 100 g of water at 25°C whose pH has been adjusted to 3.0 using hydrochloric acid or sodium hydroxide as a pH adjuster.

[0078] From the viewpoint of suppressing discoloration of the modified regenerated collagen fibers due to oxidation after treatment, the compound (A) preferably has two or less phenolic hydroxyl groups, more preferably one or less, and even more preferably zero.

[0079] <Requirements (1) and (2)> Compound (A) preferably contains a compound (excluding component (X)) that satisfies at least one of the following conditions (1) and (2): When compound (A) satisfies at least one of the following conditions (1) and (2), it is believed that chelate formation between compound (A) and polyvalent metal ions contained in the regenerated collagen fibers can be suppressed, and mass loss of the modified regenerated collagen fibers after treatment can be suppressed. (1) Al 3+ Chelate stability constant logK with ions is 2 or less (2) Molecular weight of 1500 or more

[0080] When compound (A) satisfies requirement (1), Al of compound (A) 3+ The chelate stability constant logK with ions is 2 or less. Here, the chelate stability constant is the ratio of the metal ion to M n+ The chelating agent is L m- The resulting chelate compound was expressed as ML n-m and the molar concentrations of each are [M n+ ][L m- ][ML n-m ] and M n+ +L m- ⇔ML n-m The equilibrium constant for the chelate formation reaction is K: K=[ML n-m ] / ([M n+ ]×[L m- ]) Then, it is logK. Al 3+ The chelate stability constant logK with an ion can be determined by potentiometric measurement (A. Albert & et al., "Ionic Constants" (Maruzen), p. 149 (1963)). Al in compound (A) 3+ The chelate stability constant logK with ions is preferably 1.8 or less, more preferably 1.6 or less, even more preferably 1.4 or less, still more preferably 1.2 or less, still more preferably 1.0 or less, and even more preferably 0.5 or less, from the viewpoint of further improving the effect of suppressing mass loss of the modified regenerated collagen fiber after treatment and from the viewpoint of suppressing thermal shrinkage.

[0081] When compound (A) satisfies requirement (2), the molecular weight of compound (A) is 1,500 or more. The molecular weight of compound (A) referred to here means the weight-average molecular weight of compound (A) when compound (A) is a polymer, and does not include the molecular weight of the counter ion that forms the salt when compound (A) is a salt.

[0082] When compound (A) satisfies requirement (2), the molecular weight of compound (A) is preferably 2,000 or more, more preferably 3,000 or more, and even more preferably 4,000 or more, from the viewpoint of further improving the effect of suppressing mass loss after treatment and from the viewpoint of suppressing thermal shrinkage, and is preferably 100,000,000 or less, more preferably 50,000,000 or less, even more preferably 5,000,000 or less, still more preferably 2,000,000 or less, still more preferably 100,000 or less, from the viewpoint of preventing excessive viscosity that makes application to fibers difficult. When compound (A) satisfies requirement (2), the molecular weight of compound (A) is preferably 2,000 to 100,000,000, more preferably 3,000 to 50,000,000, even more preferably 3,000 to 5,000,000, still more preferably 3,000 to 2,000,000, still more preferably 3,000 to 100,000, still more preferably 3,000 to 50,000, still more preferably 3,000 to 10,000, and still more preferably 4,000 to 10,000. When the compound (A) is a polymer, the weight average molecular weight of the compound (A) refers to the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

[0083] From the viewpoint of improving the elastic modulus of the modified regenerated collagen fibers in water, compound (A) preferably contains a compound having an acidic group, more preferably contains a compound having one or more acidic groups selected from the group consisting of a carboxy group, a sulfate group, a sulfonate group, and a phosphate group, even more preferably contains a compound having one or more acidic groups selected from the group consisting of a carboxy group and a sulfate group, and even more preferably contains a compound having a carboxy group. At least a portion of the acidic groups in the compound may be in the form of a salt. The salt preferably includes an ammonium salt or a metal salt, more preferably an ammonium salt or one or more metal salts selected from the group consisting of alkali metals, alkaline earth metals, and transition metals, more preferably an ammonium salt or one or more metal salts selected from the group consisting of potassium, sodium, and calcium, even more preferably an ammonium salt or one or more metal salts selected from the group consisting of sodium and calcium, and still more preferably a sodium salt.

[0084] The number of acidic groups in compound (A) may be at least 1. When compound (A) is a compound having a molecular weight of less than 1,500, the number of acidic groups in compound (A) is preferably at least 1, and preferably at most 50, more preferably at most 20, even more preferably at most 10, and still more preferably at most 4. That is, the number is preferably at least 1 and at most 50, more preferably at least 1 and at most 20, even more preferably at least 1 and at most 10, and still more preferably at least 1 and at most 4.

[0085] From the viewpoints of improving the modulus of elasticity of the modified regenerated collagen fibers in water, improving the effect of suppressing mass loss after treatment, and suppressing thermal shrinkage, compound (A) preferably contains at least one compound selected from the group consisting of surfactants, polymers, and carboxylic acid compounds (excluding surfactants) having the acidic group and having a molecular weight of less than 1,500.

[0086] [Surfactant] The surfactant used as compound (A) preferably contains at least one surfactant selected from the group consisting of anionic surfactants and amphoteric surfactants that satisfy the above (1). Examples of the anionic surfactant include sulfate ester-type anionic surfactants such as alkyl or alkenyl sulfates and alkyl or alkenyl ether sulfates; carboxylic acid-type anionic surfactants such as saturated or unsaturated fatty acid salts, alkyl or alkenyl ether carboxylates and N-acylamino acid salts; sulfonic acid-type anionic surfactants such as alkyl sulfosuccinates, alkyl sulfonates, α-olefin sulfonates, internal olefin sulfonates, alkylbenzene sulfonates, α-sulfofatty acid methyl ester salts and acylmethyl taurine salts; and phosphate ester-type anionic surfactants such as alkyl phosphates, polyoxyethylene alkyl ether phosphates and polyoxyethylene alkyl phenyl ether phosphates, and the like. These may be used alone or in combination of two or more.

[0087] The alkyl or alkenyl group and the fatty acid in the anionic surfactant preferably have 8 or more carbon atoms, and preferably 22 or less carbon atoms, more preferably 18 or less carbon atoms, even more preferably 14 or less carbon atoms, and even more preferably 12 or less carbon atoms. That is, the carbon number is preferably 8 to 22, more preferably 8 to 18, even more preferably 8 to 14, and even more preferably 8 to 12 carbon atoms.

[0088] Among the above, from the viewpoints of improving the modulus of elasticity of the modified regenerated collagen fibers in water, improving the effect of suppressing mass loss after treatment, and suppressing thermal shrinkage, the anionic surfactant preferably comprises one or more selected from the group consisting of sulfate ester-type anionic surfactants and carboxylic acid-type anionic surfactants, more preferably one or more selected from the group consisting of alkyl or alkenyl sulfates, alkyl or alkenyl ether sulfates, saturated or unsaturated fatty acid salts, alkyl or alkenyl ether carboxylates, and N-acylamino acid salts, and even more preferably one or more selected from the group consisting of alkyl sulfates, alkyl ether sulfates, alkyl ether carboxylates, and N-acylamino acid salts.

[0089] Among the preferred anionic surfactants used as compound (A), alkyl sulfates include sodium lauryl sulfate and ammonium lauryl sulfate, and alkyl ether sulfates include polyoxyethylene lauryl ether sulfates such as sodium laureth sulfate. Examples of alkyl ether carboxylates include polyoxyethylene lauryl ether acetate. Examples of N-acylamino acid salts include sodium N-lauroylmethylalanine.

[0090] Examples of amphoteric surfactants that satisfy the above (1) include amine oxide-type amphoteric surfactants such as alkyldimethylamine oxide and fatty acid amidopropyldimethylamine oxide; carboxybetaine-type amphoteric surfactants such as alkyldimethylaminoacetic acid betaine and fatty acid amidopropyl betaine; sulfobetaine-type amphoteric surfactants such as N-alkyl-N,N-dimethyl-N-sulfopropylammonium sulfobetaine, alkyl-N,N-dimethyl-N-(2-hydroxysulfopropyl)ammonium sulfobetaine, and N-alkanoylaminopropyl-N,N-dimethyl-N-(2-hydroxysulfopropyl)ammonium sulfobetaine; 2-alkylimidazoline-type amphoteric surfactants such as 2-alkyl-N-carboxymethylimidazolinium betaine and 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine; and amino acid-type amphoteric surfactants such as N-alkyl-β-aminopropionic acid and salts thereof, and alkyl (or dialkyl)diethylenetriaminoacetic acid and salts thereof. These may be used alone or in combination of two or more.

[0091] Among the above, from the viewpoints of improving the modulus of elasticity in water of the modified regenerated collagen fiber, improving the effect of suppressing mass loss after treatment, and suppressing thermal shrinkage, the amphoteric surfactant preferably includes one or more selected from the group consisting of amine oxide-type amphoteric surfactants, carboxybetaine-type amphoteric surfactants, and sulfobetaine-type amphoteric surfactants, more preferably includes a carboxybetaine-type amphoteric surfactant, and even more preferably includes fatty acid amidopropyl betaine. The fatty acid amidopropyl betaine preferably includes one having an acyl group having from 8 to 22 carbon atoms, more preferably from 10 to 18 carbon atoms. Specific examples thereof include lauric acid amidopropyl betaine (lauramidopropyl betaine), palm kernel oil fatty acid amidopropyl betaine, coconut oil fatty acid amidopropyl betaine (cocamidopropyl betaine), etc., and preferably includes lauric acid amidopropyl betaine (lauramidopropyl betaine).

[0092] Among the above, the surfactant used as compound (A) preferably satisfies the above (1) from the viewpoints of improving the modulus of elasticity of the modified regenerated collagen fibers in water, improving the effect of suppressing mass loss after treatment, and suppressing thermal shrinkage, and includes at least one surfactant selected from the group consisting of sulfate ester-type anionic surfactants, carboxylic acid-type anionic surfactants, amine oxide-type amphoteric surfactants, carboxybetaine-type amphoteric surfactants, and sulfobetaine-type amphoteric surfactants, and more preferably alkyl or alkenyl sulfates, alkyl or alkenyl ether sulfates, saturated or unsaturated fatty acid salts, alkyl or alkenyl ether carboxylates, N-acylamino acid salts, and carboxybetaine-type amphoteric surfactants. The composition preferably contains one or more selected from the group consisting of alkyl sulfates, alkyl ether sulfates, alkyl ether carboxylates, N-acylamino acid salts, and fatty acid amidopropyl betaines, and even more preferably contains one or more selected from the group consisting of sodium lauryl sulfate, ammonium lauryl sulfate, polyoxyethylene lauryl ether sulfate, polyoxyethylene lauryl ether acetate, sodium N-lauroylmethylalanine, lauric acid amidopropyl betaine [lauramidopropyl betaine], palm kernel oil fatty acid amidopropyl betaine, and coconut oil fatty acid amidopropyl betaine [cocamidopropyl betaine].

[0093] 〔polymer〕 The polymer used as compound (A) preferably contains one or more polymers selected from the group consisting of anionic polymers and amphoteric polymers that satisfy the above condition (2), provided that the polymer is a polymer other than component (X).

[0094] The anionic polymer used as compound (A) preferably contains at least one selected from the group consisting of anionic vinyl polymers containing structural units derived from (meth)acrylic acid and anionic polysaccharides, and at least a portion of the anionic groups in the anionic polymer may be in the form of a salt. Examples of anionic vinyl polymers containing structural units derived from (meth)acrylic acid include (meth)acrylic acid homopolymers and anionic (meth)acrylic acid copolymers. The anionic (meth)acrylic acid copolymers may be crosspolymers.

[0095] Examples of the (meth)acrylic acid homopolymer include polyacrylic acid, polymethacrylic acid, etc. The weight-average molecular weight of the (meth)acrylic acid homopolymer is preferably 3,000 to 50,000, more preferably 3,000 to 10,000, and even more preferably 4,000 to 10,000, from the viewpoints of improving the underwater elastic modulus of the modified regenerated collagen fiber, improving the effect of suppressing mass loss after treatment, and suppressing thermal shrinkage.

[0096] Examples of the anionic (meth)acrylic acid copolymer include (meth)acrylic acid / maleic acid copolymer, (meth)acrylic acid / itaconic acid copolymer, (meth)acrylic acid / fumaric acid copolymer, (meth)acrylic acid / vinyl acetate copolymer, (meth)acrylic acid / (meth)acrylic acid alkyl ester copolymer, (meth)acrylic acid / 2-hydroxyethyl methacrylate copolymer, acrylic acid / acrylic acid alkyl ester / (N-alkyl)acrylamide copolymer, carboxyvinyl polymer, (acrylates / C10-30 alkyl acrylate) crosspolymer, (acrylate sodium / acryloyldimethyltaurine / dimethylacrylamide) crosspolymer, and acrylates crosspolymer-4.

[0097] Examples of anionic polysaccharides used as compound (A) include polysaccharides having a carboxy group (hyaluronic acid, alginic acid, pectinic acid, carboxymethylcellulose, xanthan gum, etc.) and sulfated polysaccharides (carrageenan, keratan sulfate, dermatan sulfate, sulfated starch, heparin, heparan sulfate), and the like, and one or more of these can be used. Among the above, from the viewpoints of improving the modulus of elasticity in water of the modified regenerated collagen fiber, improving the effect of suppressing mass loss after treatment, and suppressing thermal shrinkage, the anionic polysaccharide preferably includes one or more selected from the group consisting of carboxymethylcellulose, xanthan gum, and carrageenan, and more preferably includes xanthan gum.

[0098] Among the above, from the viewpoints of improving the modulus of elasticity in water of the modified regenerated collagen fiber, improving the effect of suppressing mass loss after treatment, and suppressing thermal shrinkage, the anionic polymer used as compound (A) preferably contains one or more selected from the group consisting of polyacrylic acid and anionic polysaccharides, more preferably contains one or more selected from the group consisting of polyacrylic acid, carboxymethylcellulose, xanthan gum, and carrageenan, and even more preferably contains polyacrylic acid.

[0099] Examples of amphoteric polymers used as compound (A) include methacryloylethyldimethylbetaine-methacryloylethyltrimethylammonium chloride-methoxypolyethylene glycol methacrylate copolymer (Polyquaternium-49), methacryloylethyldimethylbetaine-methacryloylethyltrimethylammonium chloride-2-hydroxyethyl methacrylate copolymer (Polyquaternium-48), vinylpyrrolidone-N,N-dimethylaminoethyl diethyl methacrylate sulfate copolymer (Polyquaternium-11), and N,N-dimethylaminoethyl diethyl methacrylate sulfate-N,N-dimethylacrylic acid copolymer. Examples include acrylic acid, methyl acrylate, and methacrylamidopropyltrimethylammonium chloride copolymer (Polyquaternium-52), dimethyldiallylammonium chloride, and acrylic acid copolymer (Polyquaternium-22), acrylic acid, dimethyldiallylammonium chloride, and acrylamide copolymer (Polyquaternium-39), acrylic acid, methyl acrylate, and methacrylamidopropyltrimethylammonium chloride copolymer (Polyquaternium-47), and acrylic acid, acrylamide, and methacrylamidopropyltrimethylammonium chloride copolymer (Polyquaternium-53). One or more of these can be used in combination.

[0100] Among the above, from the viewpoints of improving the modulus of elasticity in water of the modified regenerated collagen fibers, improving the effect of suppressing mass loss after treatment, and suppressing thermal shrinkage, the amphoteric polymer preferably contains one or more members selected from the group consisting of (meth)acrylic acid-derived structural units and betaine groups, more preferably contains a (meth)acrylic acid-derived structural unit, even more preferably contains one or more members selected from the group consisting of dimethyldiallylammonium chloride-acrylic acid copolymer (Polyquaternium-22), acrylamide-acrylic acid-dimethyldiallylammonium chloride copolymer (Polyquaternium-39), acrylic acid-methyl acrylate-methacrylamidopropyltrimethylammonium chloride copolymer (Polyquaternium-47), and acrylic acid-acrylamide-methacrylamidopropyltrimethylammonium chloride copolymer (Polyquaternium-53), and even more preferably contains acrylic acid-dimethyldiallylammonium chloride-acrylamide copolymer (Polyquaternium-39).

[0101] Among the above, the polymer used as compound (A) preferably satisfies the above (2) from the viewpoints of improving the modulus of elasticity in water of the modified regenerated collagen fiber, improving the effect of suppressing mass loss after treatment, and suppressing thermal shrinkage, and contains at least one selected from the group consisting of anionic vinyl polymers containing structural units derived from (meth)acrylic acid, anionic polysaccharides, amphoteric polymers containing structural units derived from (meth)acrylic acid, and amphoteric polymers containing a betaine group, more preferably at least one selected from the group consisting of anionic vinyl polymers containing structural units derived from (meth)acrylic acid, anionic polysaccharides, and amphoteric polymers containing structural units derived from (meth)acrylic acid, and even more preferably polyacrylic acid, carboxymethyl cellulose, xanthan gum, The polyacrylic acid may contain at least one selected from the group consisting of xanthan gum, carrageenan, dimethyldiallylammonium chloride-acrylic acid copolymer (Polyquaternium-22), acrylamide-acrylic acid-dimethyldiallylammonium chloride copolymer (Polyquaternium-39), acrylic acid-methyl acrylate-methacrylamidopropyltrimethylammonium chloride copolymer (Polyquaternium-47), and acrylic acid-acrylamide-methacrylamidopropyltrimethylammonium chloride copolymer (Polyquaternium-53), and even more preferably at least one selected from the group consisting of polyacrylic acid, xanthan gum, and acrylamide-acrylic acid-dimethyldiallylammonium chloride copolymer (Polyquaternium-39). The polyacrylic acid preferably has a weight-average molecular weight of 3,000 to 50,000, more preferably 3,000 to 10,000, and even more preferably 4,000 to 10,000.

[0102] [Carboxylic acid compounds with a molecular weight of less than 1,500 (excluding surfactants)] Examples of the carboxylic acid compound include 2-pyrrolidone-5-carboxylic acid, pyruvic acid, proline, serine, glycine, leucine, arginine, glutamic acid, and histidine, and one or more of these can be used in combination. Among the above, from the viewpoints of improving the modulus of elasticity in water of the modified regenerated collagen fiber, improving the effect of suppressing mass loss after treatment, and suppressing thermal shrinkage, it is preferable to include at least one selected from the group consisting of 2-pyrrolidone-5-carboxylic acid and pyruvic acid.

[0103] The compound (A) can be used alone or in combination of two or more. Among the above, from the viewpoints of improving the modulus of elasticity in water of the modified regenerated collagen fibers, improving the effect of suppressing mass loss after treatment, and suppressing thermal shrinkage, compound (A) preferably contains one or more compounds selected from the group consisting of surfactants, polymers, and carboxylic acid compounds (excluding surfactants) having one or more acidic groups selected from the group consisting of carboxy groups and sulfate groups, more preferably one or more compounds selected from the group consisting of surfactants satisfying (1), polymers satisfying (2), and carboxylic acid compounds (excluding surfactants) having a molecular weight of less than 1500 that satisfy (1), even more preferably one or more compounds selected from the group consisting of alkyl sulfates, alkyl ether sulfates, alkyl ether carboxylates, N-acylamino acid salts, fatty acid amidopropyl betaine, anionic vinyl polymers containing structural units derived from (meth)acrylic acid, anionic polysaccharides, amphoteric polymers containing structural units derived from (meth)acrylic acid, amphoteric polymers containing a betaine group, and carboxylic acid compounds (excluding surfactants) having a molecular weight of less than 1500, and even more preferably sodium lauryl sulfate, lauryl sulfate ammonium, polyoxyethylene lauryl ether sulfate, polyoxyethylene lauryl ether acetate, N-lauroylmethylalanine sodium, lauric acid amidopropyl betaine [lauramidopropyl betaine], palm kernel oil fatty acid amidopropyl betaine, coconut oil fatty acid amidopropyl betaine [cocamidopropyl betaine], polyacrylic acid, carboxymethyl cellulose, xanthan gum, carrageenan, dimethyldiallylammonium chloride-acrylic acid copolymer (polyquaternium-22), acrylamide-acrylic acid-dimethyldiallylammonium chloride copolymer (polyquaternium-39), acrylic acid-methyl acrylate-methacrylamidopropyltrimethylammonium chloride copolymer (polyquaternium-47), acrylic acid-acrylamide-methacrylamidopropyltrimethylammonium chloride copolymer (polyquaternium-53), 2-pyrrolidone-5-carboxylic acid, and pyruvic acid, and even more preferably sodium lauryl sulfate, ammonium lauryl sulfate, sodium polyoxyethylene lauryl ether sulfate,The composition contains at least one selected from the group consisting of polyoxyethylene lauryl ether acetate, N-lauroylmethylalanine sodium, lauric acid amidopropyl betaine, polyacrylic acid, xanthan gum, acrylamide-acrylic acid-dimethyldiallylammonium chloride copolymer (polyquaternium-39), 2-pyrrolidone-5-carboxylic acid, and pyruvic acid, and even more preferably contains at least one selected from the group consisting of polyoxyethylene (3) lauryl ether sulfate, polyoxyethylene (10) lauryl ether acetate, N-lauroylmethylalanine sodium, lauric acid amidopropyl betaine, polyacrylic acid (molecular weight 5000), polyacrylic acid (molecular weight 25000), xanthan gum, acrylamide-acrylic acid-dimethyldiallylammonium chloride copolymer (polyquaternium-39), 2-pyrrolidone-5-carboxylic acid, and pyruvic acid.

[0104] [Content] From the viewpoints of improving the modulus of elasticity in water of the modified regenerated collagen fibers, improving the effect of suppressing mass loss after treatment, and suppressing thermal shrinkage, the content of compound (A) in treatment composition A is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more, still more preferably 0.2% by mass or more, still more preferably 0.5% by mass or more, still more preferably 1.0% by mass or more, still more preferably 1.5% by mass or more, and still more preferably 2.0% by mass or more. Also, the content is preferably 40% by mass or less, more preferably 30% by mass or less, still more preferably 25% by mass or less, still more preferably 20% by mass or less, still more preferably 15% by mass or less, and still more preferably 10% by mass or less. The content of compound (A) in treatment composition A is preferably 0.01% by mass or more and 40% by mass or less, more preferably 0.05% by mass or more and 30% by mass or less, even more preferably 0.1% by mass or more and 25% by mass or less, still more preferably 0.2% by mass or more and 20% by mass or less, still more preferably 0.5% by mass or more and 20% by mass or less, still more preferably 1.0% by mass or more and 20% by mass or less, still more preferably 1.5% by mass or more and 15% by mass or less, and still more preferably 2.0% by mass or more and 10% by mass or less. When compound (A) contains a polymer, the content of compound (A) in treatment composition A is even more preferably 5% by mass or more, and even more preferably 7.5% by mass or more, from the viewpoints of improving the modulus of elasticity in water of the modified regenerated collagen fibers, improving the effect of suppressing mass loss after treatment, and suppressing thermal shrinkage. When compound (A) contains a polymer, the content of compound (A) in treatment composition A is even more preferably 5% by mass or more and 10% by mass or less, and even more preferably 7.5% by mass or more and 10% by mass or less.

[0105] 〔water〕 The water used in the treatment composition A is not particularly limited, and for example, ion-exchanged water, pure water, distilled water, etc. can be used. The content of water in treatment composition A is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 75% by mass or more, and even more preferably 80% by mass or more, and is preferably 99.99% by mass or less. The content of water in treatment composition A may be the remainder of compound (A).

[0106] [Other ingredients] In addition to the above components, treatment composition A may contain an antioxidant, a fragrance, a preservative, a pH adjuster, a cationic or nonionic surfactant, a cationic or nonionic polymer, a higher alcohol, a silicone, etc. Preferably, treatment composition A contains, in addition to the above components, a cationic or nonionic surfactant, a cationic or nonionic polymer, and a higher alcohol.

[0107] [pH] The pH of treatment composition A is from 2 to 6 in terms of improving the underwater elastic modulus of the modified regenerated collagen fibers, improving the effect of suppressing mass loss after treatment, and suppressing thermal shrinkage. From the viewpoint of further improving the underwater elastic modulus of the modified regenerated collagen fibers, it is preferably 5.5 or less, more preferably 5.0 or less, even more preferably 4.5 or less, and even more preferably 4.0 or less. The pH of treatment composition A is from 2 to 6 in terms of further improving the underwater elastic modulus of the modified regenerated collagen fibers, it is preferably 2 to 5.5 or less, more preferably 2 to 5.0 or less, even more preferably 2 to 4.5 or less, and even more preferably 2 to 4.0 or less. From the viewpoint of further improving the effect of suppressing mass loss after treatment and suppressing thermal shrinkage, the pH of treatment composition A is preferably 3.0 or more, more preferably 3.5 or more, even more preferably 4.0 or more, but is 6 or less, preferably 5.5 or less. From the viewpoint of further improving the effect of suppressing mass loss after treatment and suppressing thermal shrinkage, the pH of treatment composition A is preferably 3.0 or more and 6 or less, more preferably 3.5 or more and 6 or less, even more preferably 4.0 or more and 6 or less, and still more preferably 4.0 or more and 5.5 or less. The pH of the treatment composition is the value at 25°C, and specifically, it can be measured by the method described in the examples.

[0108] [Dosage form, manufacturing method] The formulation of treatment composition A is not particularly limited, and can be in the form of a liquid, mist, paste, cream, gel, foam, spray, wax, or the like depending on the product form, with a liquid being preferred. Furthermore, treatment composition A can be used for any of the following: in-bath treatments (types that are applied to fibers for headwear products and then rinsed off) such as pre-shampoo treatments, shampoos, hair rinses, hair conditioners, hair treatments, hair packs, and after-shampoo treatments; out-bath treatments (types that are applied to fibers for headwear products and then not rinsed off) such as non-aerosol foams, aerosol foams, hair gels, hair mousses, hair mist, hair lotions, hair oils, hair creams, hair milks, hair straighteners, and styling agents; and hair coloring agents such as temporary hair dyes, semi-permanent hair dyes, and permanent hair dyes. The treating composition A can be produced in accordance with a conventional method.

[0109] (Processing method) In step (I), the method for applying treatment composition A to the regenerated collagen fibers may be any method that can bring treatment composition A into contact with the regenerated collagen fibers, and examples include a method of applying treatment composition A to dry or wet regenerated collagen fibers, and a method of immersing regenerated collagen fibers in treatment composition A. Of these, the method of immersing dry regenerated collagen fibers in treatment composition A is preferred.

[0110] In step (I), when the content of compound (A) in treatment composition A is c [mass %] and the amount of treatment composition A applied per 1 g of fiber is b [g], the total amount of compound (A) applied per 1 g of fiber, b × c / 100 [g], is preferably 0.01 g or more, more preferably 0.03 g or more, even more preferably 0.05 g or more, and still more preferably 0.10 g or more, from the viewpoint of improving the underwater elastic modulus of the modified regenerated collagen fiber, and is preferably 10 g or less, more preferably 5 g or less, even more preferably 3 g or less, and still more preferably 1 g or less, from the viewpoint of economic rationality. When the content of compound (A) in treatment composition A is c [mass %] and the amount of treatment composition applied per 1 g of dry mass of fiber is b [g], the total amount of compound (A) applied per 1 g of dry mass of fiber, b × c / 100 [g], is preferably 0.01 g or more and 10 g or less, more preferably 0.03 g or more and 5 g or less, even more preferably 0.05 g or more and 3 g or less, and still more preferably 0.1 g or more and 1 g or less. The dry mass of the fiber here means the mass of the fiber after conditioning at 20°C and a relative humidity of 65% for 24 hours.

[0111] From the viewpoint of balancing treatment effect and economic efficiency, the amount of treatment composition A applied to the regenerated collagen fibers is preferably a bath ratio (dry mass of regenerated collagen fibers:mass of treatment composition A) of 1:0.2 to 1:500, more preferably 1:0.2 to 1:200, even more preferably 1:0.5 to 1:100, and even more preferably 1:0.5 to 1:50, when the mass of the fibers after conditioning for 24 hours at 20°C and a relative humidity of 65% is taken as the dry mass. When regenerated collagen fibers are immersed in treatment composition A, the bath ratio (dry mass of regenerated collagen fibers:mass of treatment composition A) is even more preferably 1:2 to 1:50, even more preferably 1:5 to 1:50, even more preferably 1:10 to 1:50, and even more preferably 1:10 to 1:40, when the mass of the fibers after conditioning for 24 hours at 20°C and a relative humidity of 65% is taken as the dry mass. When applying treatment composition A to regenerated collagen fibers, the bath ratio (dry mass of regenerated collagen fibers:mass of treatment composition A) is even more preferably 1:0.5 to 1:20, even more preferably 1:0.5 to 1:10, even more preferably 1:0.5 to 1:5, and even more preferably 1:0.5 to 1:3, when the mass of the fibers after conditioning for 24 hours at 20°C and a relative humidity of 65% is taken as the dry mass.

[0112] When applying treatment composition A to regenerated collagen fibers, the application time is preferably 10 seconds or more, more preferably 20 seconds or more, and preferably 10 minutes or less, more preferably 5 minutes or less. The application time is preferably 10 seconds or more and 10 minutes or less, more preferably 20 seconds or more and 5 minutes or less.

[0113] After applying treatment composition A to the regenerated collagen fibers, it is preferable to further carry out a step of leaving the fibers to stand. The leaving time is preferably 1 minute or more, more preferably 3 minutes or more, and even more preferably 5 minutes or more, from the viewpoint of further improving the underwater elastic modulus after treatment, and is preferably 1 hour or less, more preferably 30 minutes or less, and even more preferably 20 minutes or less, from the viewpoint of suppressing mass loss after treatment and suppressing thermal shrinkage. The leaving time is preferably 1 minute or more and 1 hour or less, more preferably 3 minutes or more and 30 minutes or less, and even more preferably 5 minutes or more and 20 minutes or less.

[0114] When regenerated collagen fibers are immersed in treatment composition A, the immersion time is preferably 10 seconds or more, more preferably 30 seconds or more, from the viewpoint of further improving the underwater elastic modulus after treatment, and is preferably 3 hours or less, more preferably 2 hours or less, and even more preferably 90 minutes or less, from the viewpoint of improving productivity. The immersion time is preferably 10 seconds or more and 3 hours or less, more preferably 10 seconds or more and 2 hours or less, and even more preferably 30 seconds or more and 90 minutes or less.

[0115] The temperature at which treatment composition A is applied to the regenerated collagen fibers is not particularly limited, but from the viewpoint of further improving the underwater elastic modulus after treatment, it is preferably 5°C or higher, more preferably 10°C or higher, even more preferably 20°C or higher, and even more preferably 30°C or higher. Furthermore, from the viewpoint of suppressing mass loss after treatment and suppressing thermal shrinkage, it is preferably 80°C or lower, more preferably 60°C or lower, and even more preferably 50°C or lower. The temperature is preferably 5°C or higher and 80°C or lower, more preferably 10°C or higher and 60°C or lower, even more preferably 20°C or higher and 50°C or lower, and even more preferably 30°C or higher and 50°C or lower.

[0116] The method of the present invention may include a step of rinsing away excess treatment composition A applied to the regenerated collagen fibers after step (I) and before the next step (hereinafter simply referred to as the "rinsing step"). The rinsing step is carried out, for example, by rinsing away excess treatment composition A applied to the regenerated collagen fibers with water. There are no particular restrictions on the temperature of the water, but warm water at 35 to 45°C is preferred.

[0117] The method of the present invention preferably includes a step of drying the regenerated collagen fibers (hereinafter also simply referred to as a "drying step") after applying treatment composition A to the regenerated collagen fibers, or after a rinsing step, if any. The step of drying the regenerated collagen fibers is a step of reducing the moisture content of the regenerated collagen fibers, and includes, for example, towel drying, drying with a hairdryer (cold air or hot air), air drying, and a combination of two or more of these drying treatments in order to actively reduce the moisture content of the regenerated collagen fibers.

[0118] <Process (II)> In step (II), a head accessory containing the fiber for a head accessory is attached to hair dyed with hair dye B. The head accessory attached to the hair in step (II) may be a head accessory containing the modified regenerated collagen fiber after the treatment in step (I), or may be a head accessory containing the modified regenerated collagen fiber before the treatment in step (I). The modified regenerated collagen fiber may be dyed in advance with a dye or the like, and preferably is dyed after the treatment in step (I). The head accessory product can be attached to the hair by any known method appropriate for the type, shape, etc. of the head accessory product.

[0119] (Hair dye B) The hair to which the head accessory is attached in step (II) is hair dyed with hair dye B. The entire hair does not need to be dyed with hair dye B, as long as at least a portion is dyed with hair dye B. However, from the viewpoint of improving the color matching effect between the hair and the head accessory fiber containing the modified regenerated collagen fiber, it is preferable that the entire hair is dyed with hair dye B. Hair dye B can be any hair dye that can dye hair, and commercially available hair dyes may be used. However, from the viewpoint of easily penetrating the dye in hair dye B into the interior of the fibers when transferring it to and dyeing the fibers for head accessories containing modified regenerated collagen fibers, and from the viewpoint of improving the durability of the fibers for head accessories after dyeing, hair dye B is preferably a hair dye containing one or more dyes selected from the group consisting of oxidative dyes, acidic dyes, and basic dyes, and more preferably a hair dye containing an oxidative dye. The oxidative dye, acid dye, and basic dye contained in hair dye B are preferably as follows, from the viewpoint of improving the dyeability and fastness of regenerated collagen fibers, including modified regenerated collagen fibers.

[0120] [Oxidation dyes] The oxidation dye is not particularly limited, and precursors, couplers, or combinations thereof known as oxidation dye intermediates can be used. The oxidation dye preferably includes a coupler known as an oxidation dye intermediate. Examples of couplers include metaphenylenediamine, 2,4-diaminophenoxyethanol, 2-amino-4-(2-hydroxyethylamino)anisole [=2-amino-4-(β-hydroxyethyl)aminoanisole], 2,4-diamino-5-methylphenetole, 2,4-diamino-5-(2-hydroxyethoxy)toluene, 2,4-dimethoxy-1,3-diaminobenzene, 2,6-bis(2-hydroxyethylamino)toluene, and 2,4-diamino-5-fluorotoluene. , 1,3-bis(2,4-diaminophenoxy)propane, meta-aminophenol, 2-methyl-5-aminophenol [=5-aminoorthocresol], 2-methyl-5-(2-hydroxyethylamino)phenol, 2,4-dichloro-3-aminophenol, 2-chloro-3-amino-6-methylphenol, 2-methyl-4-chloro-5-aminophenol, N-cyclopentyl-meta-aminophenol, 2-methyl-4-methoxy-5-(2-hydroxyethylamino)phenol, 2 -Methyl-4-fluoro-5-aminophenol, resorcinol, 2-methylresorcinol, 4-chlororesorcinol, 1-naphthol, 1,5-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 2-isopropyl-5-methylphenol, 4-hydroxyindole, 5-hydroxyindole, 6-hydroxyindole, 7-hydroxyindole, 6-hydroxybenzomorpholine, 3,4-methylenedioxyphenol, 2-bromo-4,5- Examples thereof include one or more selected from the group consisting of methylenedioxyphenol, 3,4-methylenedioxyaniline, 1-(2-hydroxyethyl)amino-3,4-methylenedioxybenzene, 2,6-dihydroxy-3,4-dimethylpyridine, 2,6-dimethoxy-3,5-diaminopyridine, 2,3-diamino-6-methoxypyridine, 2-methylamino-3-amino-6-methoxypyridine, 2-amino-3-hydroxypyridine, 2,6-diaminopyridine, and salts thereof.

[0121] In this specification, the term "coupler" does not include compounds having a catechin structure. The "catechin structure" used here specifically refers to a structure represented by the following general formula (I):

[0122] [ka]

[0123] (In the formula, R A and R B are each independently a hydrogen atom or a hydroxy group. C is a hydrogen atom or an acyl group, and R D is a hydrogen atom or a ring-containing group.

[0124] R C The acyl group in the formula (II) is preferably a group represented by the following formula (II), and R D The ring structure-containing group in the formula (III) is preferably a group represented by the following formula (III).

[0125] [ka]

[0126] [ka]

[0127] (In the above formula, * indicates a bond. R A ~R C is the same as above.)

[0128] From the viewpoint of improving the dyeability and fastness of the modified regenerated collagen fiber, the oxidation dye is preferably an oxidation dye intermediate (B) containing one or more members selected from the group consisting of the following components (B1) and (B2): (B1) One or more couplers selected from the group consisting of couplers (B1-1) having a benzene ring, electron-donating groups at the 1st and 3rd positions on the benzene ring, and hydrogen atoms at the 4th and 6th positions; couplers (B1-2) having a pyridine ring, electron-donating groups at the 2nd and 6th positions on the pyridine ring, and hydrogen atoms at the 3rd and 5th positions; and couplers (B1-3) represented by the following general formula (B13):

[0129] [ka]

[0130] (In formula (B13), R 11 is -O-(CH2) n R is a divalent group represented by -O- (n is a number of 2 or more and 10 or less). 12 , R 14 , R 22 and R 24 is an electron-donating group, and R 15 and R 25 is a hydrogen atom. 13 , R 16 , R 23 and R 26 are each independently a hydrogen atom, an alkyl group, or an electron-donating group.

[0131] (B2) One or more couplers other than the component (B1), selected from the group consisting of couplers (B2-1) having a benzene ring, electron-donating groups at the 1st and 2nd positions on the benzene ring, and hydrogen atoms at two or more of the 3rd to 6th positions, and couplers (B2-2) having a pyridine ring, electron-donating groups at the 2nd and 3rd positions on the pyridine ring, and hydrogen atoms at two or more of the 4th to 6th positions.

[0132] Component (B1) is a coupler having a specific structure, which makes it easy for component (B1) to form a trimer or higher reaction product. Similarly, component (B2), a coupler, also has a specific structure, which makes it easy for component (B2) to form a dimer or higher reaction product. Therefore, when one or more oxidation dye intermediates (B) selected from the group consisting of components (B1) and (B2) are used, high-molecular-weight reaction products are easily produced inside the fiber, which is thought to improve fastness.

[0133] [Component (B1)] Component (B1) is at least one selected from the group consisting of couplers (B1-1) having a benzene ring, electron-donating groups at the 1- and 3-positions on the benzene ring, and hydrogen atoms at the 4- and 6-positions; couplers (B1-2) having a pyridine ring, electron-donating groups at the 2- and 6-positions on the pyridine ring, and hydrogen atoms at the 3- and 5-positions; and couplers (B1-3) represented by the following general formula (B13):

[0134] [ka]

[0135] (In formula (B13), R 11 is -O-(CH2) n R is a divalent group represented by -O- (n is a number of 2 or more and 10 or less). 12 , R 14 , R 22 and R 24 is an electron-donating group, and R 15 and R 25 is a hydrogen atom. 13 , R 16 , R 23 and R 26 are each independently a hydrogen atom, an alkyl group, or an electron-donating group.

[0136] Examples of the electron-donating group in component (B1) include a hydroxy group, a hydroxyalkyl group, an alkoxy group, a hydroxyalkoxy group, a primary to tertiary amino group, an alkylamino group, and an aromatic hydrocarbon ring structure.

[0137] <Coupler (B1-1)> The coupler (B1-1) preferably includes a compound represented by the following general formula (B11).

[0138] [ka]

[0139] (In formula (B11), R 1 is an electron donating group attached to the carbon atom at position 1, R 2 is a hydrogen atom attached to the carbon atom at the 2nd position, an alkyl group or an electron-donating group, R 3 is an electron donating group attached to the 3-carbon atom, R 4 is a hydrogen atom, an alkyl group, or an electron-donating group bonded to the carbon atom at the 5-position. 2 and R 3 may be bonded to each other to form a hydrocarbon ring structure having aromaticity.

[0140] The electron-donating group in general formula (B11) preferably includes at least one selected from the group consisting of a hydroxy group, a hydroxyalkyl group, an alkoxy group, a hydroxyalkoxy group, a primary to tertiary amino group, an alkylamino group, and a hydrocarbon ring structure having aromaticity, more preferably includes at least one selected from the group consisting of a hydroxy group, a hydroxyalkyl group having from 2 to 8 carbon atoms, an alkoxy group having from 1 to 8 carbon atoms, a hydroxyalkoxy group having from 2 to 8 carbon atoms, a primary amino group (-NH2), and an alkylamino group having from 1 to 8 carbon atoms, and even more preferably includes at least one selected from the group consisting of a hydroxy group and a primary amino group (-NH2). The alkyl group preferably includes an alkyl group having 1 to 8 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, and even more preferably a methyl group. The aromatic hydrocarbon ring structure is represented by R 2 and R 3are bonded to each other to form an aromatic hydrocarbon ring structure, the ring structure preferably includes an aromatic hydrocarbon ring structure having 5 to 8 ring carbon atoms, more preferably includes an aromatic hydrocarbon ring structure having 5 to 6 ring carbon atoms, and even more preferably includes an aromatic hydrocarbon ring structure having 6 ring carbon atoms.

[0141] In the general formula (B11), R 1 is preferably a hydroxy group or a primary amino group (-NH). 2 is preferably a hydrogen atom or a methyl group, R 3 is preferably a hydroxy group or a primary amino group (-NH). 2 and R 3 are bonded to each other to form an aromatic hydrocarbon ring structure with 6 ring carbon atoms. 4 is preferably a hydrogen atom or a methyl group, more preferably a hydrogen atom.

[0142] Specific examples of the compound represented by the general formula (B11) include one or more compounds selected from the group consisting of meta-aminophenol, resorcinol, meta-phenylenediamine, 2-methylresorcinol, and 1-naphthol, and preferably include one or more compounds selected from the group consisting of meta-aminophenol, resorcinol, 2-methylresorcinol, and 1-naphthol.

[0143] <Coupler (B1-2)> The coupler (B1-2) preferably includes a compound represented by the following general formula (B12).

[0144] [ka]

[0145] (In formula (B12), R 5 is an electron donating group attached to the 2nd carbon atom, R 6 represents a hydrogen atom, an alkyl group, or an electron-donating group bonded to the 4-carbon atom; R 7 is an electron-donating group attached to the 6-carbon atom.)

[0146] The electron-donating group in general formula (B12) preferably includes one or more selected from the group consisting of a hydroxy group, a hydroxyalkyl group, an alkoxy group, a hydroxyalkoxy group, a primary to tertiary amino group, and an alkylamino group, more preferably includes one or more selected from the group consisting of a hydroxy group, a hydroxyalkyl group having from 2 to 8 carbon atoms, an alkoxy group having from 1 to 8 carbon atoms, a hydroxyalkoxy group having from 2 to 8 carbon atoms, a primary amino group (-NH2), and an alkylamino group having from 1 to 8 carbon atoms, and even more preferably includes one or more selected from the group consisting of a hydroxy group and a primary amino group (-NH2). The alkyl group preferably includes an alkyl group having 1 to 8 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, and even more preferably a methyl group.

[0147] In the general formula (B12), R 5 is preferably a hydroxy group or a primary amino group (—NH), and R 6 is preferably a hydrogen atom or a methyl group. 7 is preferably a primary amino group (-NH2). A specific example of the compound represented by the general formula (B12) is 2,6-diaminopyridine.

[0148] <Coupler (B1-3)> The coupler (B1-3) includes a compound represented by the following general formula (B13).

[0149] [ka]

[0150] (In formula (B13), R 11 is -O-(CH2) n R is a divalent group represented by -O- (n is a number of 2 or more and 10 or less). 12 , R 14 , R 22 and R 24 is an electron-donating group, and R15 and R 25 is a hydrogen atom. 13 , R 16 , R 23 and R 26 are each independently a hydrogen atom, an alkyl group, or an electron-donating group.

[0151] The electron-donating group, the alkyl group, and preferred embodiments thereof in general formula (B13) are the same as those in general formula (B12).

[0152] In general formula (B13), R 11 In the formula, n is preferably 2 or more and 8 or less, and more preferably 2 or more and 4 or less. R 12 , R 14 , R 22 and R 24 The electron donating group in R preferably comprises a hydroxy group or a primary amino group (-NH), more preferably a primary amino group (-NH). 13 , R 16 , R 23 and R 26 preferably contains a hydrogen atom or a methyl group, and more preferably is a hydrogen atom. A specific example of the coupler represented by the general formula (B13) is 1,3-bis(2,4-diaminophenoxy)propane.

[0153] As the component (B1), one or more members selected from the group consisting of the couplers (B1-1), (B1-2), and (B1-3) can be used. Among the above, component (B1) preferably contains one or more selected from the group consisting of meta-aminophenol, resorcinol, meta-phenylenediamine, 2-methylresorcinol, 1-naphthol, 2,6-diaminopyridine, and 1,3-bis(2,4-diaminophenoxy)propane, and more preferably contains one or more selected from the group consisting of meta-aminophenol, resorcinol, 2-methylresorcinol, and 1-naphthol.

[0154] [Component (B2)] Component (B2) is a coupler other than component (B1), and is at least one selected from the group consisting of couplers (B2-1) having a benzene ring, electron-donating groups at the 1- and 2-positions on the benzene ring, and hydrogen atoms at two or more of the 3- to 6-positions, and couplers (B2-2) having a pyridine ring, electron-donating groups at the 2- and 3-positions on the pyridine ring, and hydrogen atoms at two or more of the 4- to 6-positions.

[0155] Coupler (B2-1) The coupler (B2-1) preferably includes a compound represented by the following general formula (B21): However, couplers corresponding to the above component (B1) are excluded.

[0156] [ka]

[0157] (In formula (B21), R 31 is an electron donating group attached to the carbon atom at position 1, R 32 is an electron donating group attached to the 2nd carbon atom, R 33 ~R 36 are hydrogen atoms, alkyl groups, or electron-donating groups bonded to the 3-, 4-, 5-, and 6-position carbons, respectively. 33 ~R 36 At least two of these are hydrogen atoms.)

[0158] The electron-donating group in general formula (B21) preferably includes one or more selected from the group consisting of a hydroxy group, a hydroxyalkyl group, an alkoxy group, a hydroxyalkoxy group, a primary to tertiary amino group, and an alkylamino group, more preferably includes one or more selected from the group consisting of a hydroxy group, a hydroxyalkyl group having from 2 to 8 carbon atoms, an alkoxy group having from 1 to 8 carbon atoms, a hydroxyalkoxy group having from 2 to 8 carbon atoms, a primary amino group (-NH2), and an alkylamino group having from 1 to 8 carbon atoms, and even more preferably includes one or more selected from the group consisting of a hydroxy group, a hydroxyalkoxy group having from 2 to 8 carbon atoms, and a primary amino group (-NH2). The alkyl group preferably includes an alkyl group having 1 to 8 carbon atoms, more preferably includes an alkyl group having 1 to 3 carbon atoms, and further preferably includes a methyl group.

[0159] In general formula (B21), R 31 is preferably a hydroxy group, a hydroxyalkoxy group having from 2 to 8 carbon atoms, or a primary amino group (-NH), and more preferably a hydroxy group, a hydroxyethoxy group, or a primary amino group (-NH). 32 is preferably a hydroxy group or a primary amino group (-NH2), more preferably a primary amino group (-NH2).

[0160] Specific examples of the compound represented by general formula (B21) include orthoaminophenol, 2,4-diaminophenoxyethanol, and the like.

[0161] Coupler (B2-2) The coupler (B2-2) preferably includes a compound represented by the following general formula (B22).

[0162] [ka]

[0163] (In formula (B22), R 37 is an electron donating group attached to the 2nd carbon atom, R 38 is an electron donating group attached to the 3-carbon atom. 39 ~R 41 are hydrogen atoms, alkyl groups, or electron-donating groups bonded to the 4-, 5-, and 6-position carbons, respectively. 39 ~R 41 At least two of these are hydrogen atoms.)

[0164] The electron-donating group, the alkyl group, and preferred embodiments thereof in general formula (B22) are the same as those in general formula (B21).

[0165] In the general formula (B22), R 37is preferably a hydroxy group or a primary amino group (—NH), and R 38 is preferably a hydroxy group or a primary amino group (-NH), more preferably a primary amino group (-NH). 39 ~R 41 are each independently preferably a hydrogen atom or a methyl group, more preferably R 39 ~R 41 All of these are hydrogen atoms. Specific examples of the compound represented by the general formula (B22) include 2,3-diaminopyridine, 2-amino-3-hydroxypyridine, and salts thereof.

[0166] As the component (B2), one or more members selected from the group consisting of the couplers (B2-1) and (B2-2) can be used. Among the above, the component (B2) preferably contains a coupler (B2-1), and more preferably contains one or more selected from the group consisting of ortho-aminophenol and 2,4-diaminophenoxyethanol.

[0167] Among the above, from the viewpoint of compatibility, the oxidation dye intermediate (B) preferably contains component (B1), and more preferably contains one or more selected from the group consisting of meta-aminophenol, resorcinol, meta-phenylenediamine, 2-methylresorcinol, 1-naphthol, 2,6-diaminopyridine, and 1,3-bis(2,4-diaminophenoxy)propane. The oxidation dye intermediate (B) preferably contains a coupler (B1-1), more preferably one or more selected from the group consisting of meta-aminophenol, resorcinol, 2-methylresorcinol, and 1-naphthol.

[0168] From the viewpoint of improving dyeability and fastness, the total content of components (B1) and (B2) in the oxidation dye intermediate (B) is preferably 30% by mass or more, more preferably 40% by mass or more, and 100% by mass or less. Furthermore, when the oxidation dye intermediate (B) contains another oxidation dye intermediate (for example, a precursor of component (B3) described below), the total content of components (B1) and (B2) in the oxidation dye intermediate (B) may be, for example, 90% by mass or less, 80% by mass or less, 70% by mass or less, or 60% by mass or less.

[0169] From the viewpoint of improving dyeability and fastness, the content of component (B1) in the oxidation dye intermediate (B) is preferably 30% by mass or more, more preferably 40% by mass or more, and 100% by mass or less. The content of component (B1) in the oxidation dye intermediate (B) may be, for example, 90% by mass or less, 80% by mass or less, 70% by mass or less, or 60% by mass or less.

[0170] [Component (B3): Precursor] From the viewpoint of further improving dyeability and fastness, the oxidation dye intermediate (B) preferably further contains component (B3): precursor as an oxidation dye intermediate other than the components (B1) and (B2). The precursor can be any compound known as a precursor of an oxidation dye intermediate, without any limitation, and examples thereof include paraphenylenediamine, toluene-2,5-diamine, orthochloroparaphenylenediamine, N-phenylparaphenylenediamine, N,N-bis(hydroxyethyl)paraphenylenediamine, 3-methyl-4-aminophenol, 2-hydroxyethylparaphenylenediamine, paraaminophenol, paramethylaminophenol, 4-amino-metacresol, and salts thereof.

[0171] Among the above, from the viewpoint of further improving dyeability and fastness when used in combination with the couplers of components (B1) and (B2), component (B3) preferably contains one or more selected from the group consisting of toluene-2,5-diamine, para-aminophenol, 4-amino-metacresol, 1-hydroxyethyl-4,5-diaminopyrazole, and salts thereof.

[0172] When the oxidation dye intermediate (B) contains component (B3), the content of component (B3) in the oxidation dye intermediate (B) is preferably 20% by mass or more, more preferably 30% by mass or more, even more preferably 40% by mass or more, and is preferably 70% by mass or less, more preferably 65% ​​by mass or less, and even more preferably 60% by mass or less, from the viewpoint of further improving dyeability and fastness. When the oxidation dye intermediate (B) contains component (B3), the content of component (B3) in the oxidation dye intermediate (B) is preferably 20% by mass or more and 70% by mass or less, more preferably 30% by mass or more and 65% by mass or less, and even more preferably 40% by mass or more and 60% by mass or less.

[0173] The oxidation dye intermediate (B) may further contain a coupler other than the components (B1) and (B2). However, from the viewpoint of further improving dyeability and fastness, the total content of the components (B1) to (B3) in the oxidation dye intermediate (B) is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, still more preferably 95% by mass or more, and even more preferably 98% by mass or more, but not more than 100% by mass. That is, the content of couplers other than the components (B1) and (B2) in the oxidation dye intermediate (B) is preferably 30% by mass or less, more preferably 20% by mass or less, even more preferably 10% by mass or less, still more preferably 5% by mass or less, and even more preferably 2% by mass or less, and may be 0% by mass.

[0174] From the viewpoint of further improving dyeability and fastness, the molecular weight of the oxidation dye intermediate (B) is, as a non-dissociated type, preferably 95 or more, more preferably 100 or more, and even more preferably 105 or more, and from the viewpoint of efficiently penetrating into the interior of the fiber to further improve dyeability, the molecular weight of the oxidation dye intermediate (B) is, as a non-dissociated type, preferably 500 or less, more preferably 300 or less, and even more preferably 200 or less. The molecular weight of the oxidation dye intermediate (B) is, as a non-dissociated type, preferably 95 or more and 500 or less, more preferably 100 or more and 300 or less, and even more preferably 105 or more and 200 or less. The molecular weight of the oxidative dye intermediate (B) refers to the molecular weight of each oxidative dye intermediate in the oxidative dye intermediate (B), and it is preferable that the undissociated molecular weights of the components (B1), (B2), and (B3) are all within the above range. Furthermore, the undissociated molecular weight of the oxidative dye intermediate (B) refers to the molecular weight of the oxidative dye intermediate (B) in a non-ionic state, even when the oxidative dye intermediate (B) is a salt, and does not include the molecular weight of the counter ion. This also includes cases where the oxidative dye intermediate (B) has an onium group such as a quaternary ammonium group, and in such cases, the counter ion is similarly not included in the molecular weight.

[0175] When the dye used in hair dye B includes an oxidation dye, hair dye B is preferably a multi-part hair dye comprising a first part and a second part. Here, the first agent contains the oxidation dye intermediate (B), an alkaline agent, and water, and the second agent contains hydrogen peroxide and water.

[0176] [Alkaline agent] The alkaline agent used in the first agent may be either an inorganic alkaline agent or an organic alkaline agent. Examples of the alkaline agent include ammonia; alkanolamines such as mono-, di-, or trimethanolamine, and mono-, di-, or triethanolamine; alkylamines such as methylamine, dimethylamine, ethylamine, diethylamine, N-methylethylamine, propylamine, and butylamine; aralkylamines such as benzylamine; and inorganic alkali compounds such as sodium hydroxide and potassium hydroxide, and one or more of these can be used. From the viewpoint of water solubility, the number of carbon atoms in the alkanolamine, alkylamine, or aralkylamine is preferably 10 or less, and more preferably 8 or less. Among the above, from the viewpoint of efficiently penetrating the oxidation dye intermediate (B) into the interior of the fiber to further improve dyeability and fastness, the alkaline agent preferably contains one or more selected from the group consisting of ammonia, alkanolamine, alkylamine, aralkylamine, sodium hydroxide, and potassium hydroxide, and more preferably contains one or more selected from the group consisting of ammonia and alkanolamine.

[0177] 〔water〕 The water used in the first agent is not particularly limited, and for example, ion-exchanged water, pure water, distilled water, etc. can be used.

[0178] [Other ingredients] In addition to the above ingredients, the first agent may contain antioxidants, fragrances, preservatives, thickeners, pH adjusters, surfactants, texture improvers, and the like.

[0179] The content of each component in the first agent is preferably within the following ranges. From the viewpoint of improving dyeability, the content of the oxidation dye intermediate (B) in the first agent is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, even more preferably 0.05% by mass or more, still more preferably 0.1% by mass or more, still more preferably 0.2% by mass or more, still more preferably 0.3% by mass or more, and still more preferably 0.5% by mass or more, and from the viewpoint of improving formulation stability, it is preferably 5.0% by mass or less, more preferably 3.0% by mass or less, and still more preferably 2.0% by mass or less. The content of the oxidation dye intermediate (B) in the first agent is preferably 0.01% by mass or more and 5.0% by mass or less, more preferably 0.02% by mass or more and 3.0% by mass or less, even more preferably 0.05% by mass or more and 3.0% by mass or less, still more preferably 0.1% by mass or more and 3.0% by mass or less, still more preferably 0.2% by mass or more and 3.0% by mass or less, still more preferably 0.3% by mass or more and 3.0% by mass or less, and still more preferably 0.5% by mass or more and 2.0% by mass or less.

[0180] From the viewpoint of improving dyeability, the total content of component (B1) and component (B2) in the first agent is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, even more preferably 0.05% by mass or more, still more preferably 0.1% by mass or more, still more preferably 0.2% by mass or more, and still more preferably 0.25% by mass or more, and from the viewpoint of improving formulation stability, it is preferably 5.0% by mass or less, more preferably 3.0% by mass or less, even more preferably 2.0% by mass or less, still more preferably 1.5% by mass or less, and still more preferably 1.0% by mass or less. The total content of component (B1) and component (B2) in the first agent is preferably 0.01% by mass or more and 5.0% by mass or less, more preferably 0.02% by mass or more and 3.0% by mass or less, even more preferably 0.05% by mass or more and 2.0% by mass or less, still more preferably 0.1% by mass or more and 1.5% by mass or less, even more preferably 0.2% by mass or more and 1.5% by mass or less, and still more preferably 0.25% by mass or more and 1.0% by mass or less.

[0181] From the viewpoint of improving dyeability and fastness, the content of the alkaline agent in the first agent is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.5% by mass or more, and even more preferably 1.0% by mass or more. From the viewpoint of maintaining constant reactivity, it is preferably 10% by mass or less, more preferably 7.5% by mass or less, and even more preferably 5.0% by mass or less. The content of the alkaline agent in the first agent is preferably 0.01% by mass or more and 10% by mass or less, more preferably 0.1% by mass or more and 7.5% by mass or less, even more preferably 0.5% by mass or more and 7.5% by mass or less, and even more preferably 1.0% by mass or more and 5.0% by mass or less. The content of the alkaline agent herein means an effective amount of the alkaline agent.

[0182] The content of water in the first agent is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 85% by mass or more, and preferably 99.98% by mass or less, from the viewpoint of improving the solubility of the oxidation dye intermediate (B) and the alkaline agent, and from the viewpoint of improving the ease of handling when mixed with the second agent. The content of water in the first agent may be the balance of the oxidation dye intermediate (B) and the alkaline agent.

[0183] (pH) From the viewpoint of improving dyeability and fastness, the pH of the first agent is preferably 6 or higher, more preferably 8 or higher, and even more preferably 10 or higher. From the viewpoint of maintaining constant reactivity, the pH is preferably 12.0 or lower, more preferably 11.5 or lower, and even more preferably 11.0 or lower. The pH of the first agent is preferably 6 or higher and 12 or lower, more preferably 8 or higher and 11.5 or lower, and even more preferably 10 or higher and 11.0 or lower. The pH can be measured at 25°C by the method described in the Examples.

[0184] (Dosage form, manufacturing method) The dosage form of the first agent is not particularly limited, and can be liquid, paste, cream, gel, foam, spray, wax, or other dosage form depending on the product form, with liquid being preferred. The first agent can be produced according to a conventional method.

[0185] The second agent contains hydrogen peroxide and water. The content of hydrogen peroxide in the second agent is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1.0% by mass or more from the viewpoint of improving dyeability and fastness, and is preferably 10.0% by mass or less, more preferably 8.0% by mass or less from the viewpoint of suppressing damage to the fibers. The content of hydrogen peroxide in the second agent is preferably 0.1% by mass or more and 10% by mass or less, more preferably 0.5% by mass or more and 10% by mass or less, and even more preferably 1.0% by mass or more and 8.0% by mass or less. From the viewpoint of ease of handling, hydrogen peroxide is preferably blended in the form of an aqueous solution. In this specification, the content of hydrogen peroxide in the second agent means an effective amount of hydrogen peroxide.

[0186] 〔water〕 The water used in the second agent is not particularly limited, and for example, ion-exchanged water, pure water, distilled water, etc. can be used. From the viewpoint of improving the ease of handling when mixed with the first agent, the water content in the second agent is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 85% by mass or more, and is preferably 99.9% by mass or less. The content of water in the second agent comprises the remainder of the hydrogen peroxide.

[0187] [Other ingredients] In addition to the above ingredients, the second agent may contain antioxidants, fragrances, preservatives, thickeners, pH adjusters, surfactants, texture improvers, and the like.

[0188] (pH) The pH of the second agent is preferably 2.5 or higher, more preferably 3.0 or higher, and is preferably 6 or lower, more preferably 5 or lower, and even more preferably 4 or lower. The pH of the second agent is preferably 2.5 or higher and 6 or lower, more preferably 2.5 or higher and 5 or lower, and even more preferably 3.0 or higher and 4 or lower. The pH can be measured at 25°C by the method described in the Examples.

[0189] (Dosage form, manufacturing method) The dosage form of the second agent is not particularly limited, and can be liquid, paste, cream, gel, foam, spray, wax, or other dosage form depending on the product form, with liquid being preferred. The first and second agents may be in the same or different dosage forms, but from the viewpoint of ease of handling during use, it is preferable that they be in the same dosage form. The second agent can be prepared according to a conventional method.

[0190] Multi-component hair dyes are used by mixing at least the first and second agents. Note that multi-component hair dyes may be used by mixing at least the first and second agents, and may also include those that further mix a third or more agents containing other ingredients. The mixing ratio of the first agent to the second agent varies depending on the concentrations of the oxidative dye intermediate (B) and alkaline agent in the first agent and the hydrogen peroxide in the second agent, but the first agent:second agent (mass ratio) is preferably in the range of 1:0.1 to 1:10, more preferably 1:0.2 to 1:5, and even more preferably 1:0.5 to 1:3.

[0191] [Acid dye] Any known acid dye can be used as the acid dye without any particular restrictions. However, from the viewpoint of improving the fastness of the modified regenerated collagen fiber after dyeing, the acid dye preferably includes an acid dye (C) that has a sulfonic acid group and satisfies at least one of the following (3) and (4): (3) Molecular weight of 500 or more (4) When the molecular weight is Mw, the difference (ab) between the number of sulfonic acid groups (a) and the number of cationic sites (b) divided by Mw [(ab) / Mw] is 0.0045 or less. The molecular weight of the acid dye here refers to the molecular weight in an undissociated (acid) state. For example, even if at least a portion of the sulfonic acid groups in the acid dye are in the form of sulfonate salts, the molecular weight of the acid dye refers to the molecular weight in the undissociated sulfonic acid state, and does not include the molecular weight of the counter ion. This also includes cases where the acid dye has an onium group such as a quaternary ammonium group, but in such cases, the counter ion is similarly not included in the molecular weight. The acid dye (C) may be an acid dye that satisfies either one of the above (3) and (4), or may be an acid dye that satisfies both the above (3) and (4).

[0192] Because the acid dye (C) has a sulfonic acid group, it interacts with the structural moieties derived from the components (X) and (Y) inside the modified regenerated collagen fiber, making it easier for the acid dye (C) to remain inside the fiber, which is thought to further improve fastness. Furthermore, acid dyes that satisfy the above condition (3) have a large molecular weight, so that they are less likely to fade after dyeing and can improve color fastness. Furthermore, since the object to be dyed is regenerated collagen fibers, it is thought that, unlike hair, it will be possible to dye the fibers by penetrating the acid dye into the fibers. When an acid dye that satisfies the above condition (4) has a value [(ab) / Mw] obtained by dividing the difference (ab) between the number of sulfonic acid groups (a) and the number of cationic sites (b) in the acid dye by Mw, which is a predetermined value or less, the repulsion between the negative charges between the structural portion derived from compound (X) in the modified regenerated collagen fiber and the acid dye can be sufficiently reduced, and it is thought that this improves the fixation of the acid dye to the modified regenerated collagen fiber, thereby further improving the dyeability and fastness.

[0193] The number (a) of sulfonic acid groups in the acid dye (C) may be 1 or more, and from the viewpoint of improving the dyeability and fastness of the modified regenerated collagen fibers, it is preferably 1 or more, more preferably 2 or more, and preferably 6 or less, more preferably 5 or less, even more preferably 4 or less, and still more preferably 3 or less. That is, the number (a) of sulfonic acid groups in the acid dye (C) is preferably 1 or more and 6 or less, more preferably 1 or more and 5 or less, even more preferably 1 or more and 4 or less, still more preferably 1 or more and 3 or less, and still more preferably 2 or more and 3 or less. The "number (a) of sulfonic acid groups in the acid dye (C)" herein means the number of sulfonic acid groups in the acid dye (C) in a non-dissociated (acid) state.

[0194] The acid dye (C) may be at least partially in the form of a salt, and from the viewpoint of improving the dyeability and fastness of the modified regenerated collagen fiber, the salt preferably includes an ammonium salt or a metal salt, more preferably an ammonium salt or one or more metal salts selected from the group consisting of alkali metals, alkaline earth metals, and transition metals, more preferably an ammonium salt or one or more metal salts selected from the group consisting of potassium, sodium, calcium, iron, and chromium, even more preferably an ammonium salt or one or more metal salts selected from the group consisting of sodium, calcium, iron, and chromium, and even more preferably a sodium salt.

[0195] From the viewpoint of improving the fastness of the modified regenerated collagen fibers, it is preferable that the acid dye (C) further has a cationic moiety. Examples of the cationic moiety include quaternary ammonium cationic moieties and iminium cationic moieties, and from the viewpoint of improving the robustness of the modified regenerated collagen fiber, it preferably contains an iminium cationic moiety.

[0196] The number of cationic moieties (b) in the acid dye (C) may be 0. When the acid dye (C) has cationic moieties, from the viewpoint of improving the fastness of the modified regenerated collagen fibers, the number of cationic moieties (b) in the acid dye (C) is preferably 1 or more and preferably 5 or less, more preferably 4 or less, even more preferably 3 or less, and still more preferably 2 or less. That is, it is preferably 1 or more and 5 or less, more preferably 1 or more and 4 or less, even more preferably 1 or more and 3 or less, and still more preferably 1 or more and 2 or less. The number (b) of cationic moieties in the acid dye (C) is preferably 0 or more and 5 or less, more preferably 0 or more and 4 or less, even more preferably 0 or more and 3 or less, still more preferably 0 or more and 2 or less, and still more preferably 1 or more and 2 or less.

[0197] From the viewpoint of improving the fastness of the modified regenerated collagen fibers, the difference (ab) between the number of sulfonic acid groups (a) in the acid dye (C) and the number of cationic sites (b) in the acid dye (C) is preferably 1 or more, and preferably 5 or less, more preferably 4 or less, even more preferably 3 or less, and still more preferably 2 or less. That is, it is preferably 1 or more and 5 or less, more preferably 1 or more and 4 or less, even more preferably 1 or more and 3 or less, and still more preferably 1 or more and 2 or less.

[0198] From the viewpoint of improving the dyeability and fastness of the modified regenerated collagen fiber, it is preferable that the acid dye (C) has a small number of carboxy groups, and the number of carboxy groups in the acid dye (C) is preferably 2 or less, more preferably 1 or less, and even more preferably 0.

[0199] (Requirement (3)) The acid dye (C) that satisfies the above condition (3) has a sulfonic acid group and a molecular weight of 500 or more. When the acid dye (C) satisfies the above (3), from the viewpoint of improving the fastness of the modified regenerated collagen fibers after dyeing, the molecular weight of the acid dye (C) is preferably 520 or more, more preferably 540 or more, and is also preferably 1,500 or less, more preferably 1,200 or less, even more preferably 1,000 or less, still more preferably 900 or less, still more preferably 800 or less, still more preferably 780 or less, and still more preferably 750 or less. When the acid dye (C) satisfies the above (1), the molecular weight of the acid dye (C) is preferably 500 or more and 1,500 or less, more preferably 500 or more and 1,200 or less, even more preferably 500 or more and 1,000 or less, still more preferably 500 or more and 900 or less, still more preferably 500 or more and 800 or less, still more preferably 500 or more and 780 or less, still more preferably 520 or more and 750 or less, and still more preferably 540 or more and 750 or less.

[0200] (Requirement (4)) When the acid dye (C) satisfies the above (4), the difference (ab) between the number of sulfonic acid groups in the acid dye (C) (a) and the number of cationic sites in the acid dye (C) (b), divided by Mw, [(ab) / Mw], where Mw is the molecular weight of the acid dye (C) (molecular weight in the undissociated (acid) state), is 0.0045 or less, preferably 0.0040 or less, more preferably 0.0035 or less, and even more preferably 0.0025 or less, from the viewpoint of improving the dyeability and fastness of the modified regenerated collagen fibers. Furthermore, when the acid dye (C) satisfies the above (4), [(ab) / Mw] is preferably 0.0005 or more, more preferably 0.0010 or more. When the acid dye (C) satisfies the above (4), [(ab) / Mw] is preferably 0.0005 or more and 0.0045 or less, more preferably 0.0005 or more and 0.0040 or less, even more preferably 0.0010 or more and 0.0035 or less, and still more preferably 0.0010 or more and 0.0025 or less.

[0201] When the acid dye (C) satisfies the above condition (4), the molecular weight Mw is preferably 250 or more, more preferably 280 or more, even more preferably 300 or more, and still more preferably 320 or more. Also, it is preferably 1,500 or less, more preferably 1,200 or less, even more preferably 1,000 or less, still more preferably 900 or less, still more preferably 800 or less, still more preferably 780 or less, and still more preferably 750 or less. When the acid dye (C) satisfies the above condition (4), the molecular weight Mw is preferably 250 or more and 1,500 or less, more preferably 250 or more and 1,200 or less, even more preferably 250 or more and 1,000 or less, still more preferably 250 or more and 900 or less, still more preferably 280 or more and 800 or less, still more preferably 280 or more and 780 or less, still more preferably 280 or more and 750 or less, still more preferably 300 or more and 750 or less, and still more preferably 320 or more and 750 or less.

[0202] The acid dye (C) may satisfy both of the above (3) and (4), and in that case, the molecular weight of the acid dye (C) is 500 or more and [(ab) / Mw] is 0.0045 or less. The preferred ranges of the molecular weight and [(ab) / Mw] of the oxidation dye (C) are the same as those described above.

[0203] From the viewpoint of improving the dyeability and fastness of the modified regenerated collagen fiber, the acid dye (C) is preferably Acid Black 52 (Color Index No. 15711), Acid Green 1 (Color Index No. 10020), Food Black 1 (Color Index No. 28440), Food Green 3 (Color Index No. 42053), Acid Green 5 (Color Index No. 42095), Acid Blue 9 (Color Index No. 42090), Acid Blue 5 (Color Index No. 42052), Acid Green 3 (Color Index No. 42085), Acid Green 25 (Color Index No. 61570), Acid Brown 13 (Color Index No. 10410), Acid Red 52 (Color Index No. 45100), Acid Black 1 (Color Index No. 20470), Acid Red 18 (Color Index No. 10410), or No.16255), Acid Red 27(Color Index No.16185), Acid Blue 3(Color Index No.42051), Acid Green 50(Color Index No.44090), Acid Red 73(Color Index No.27290), Acid Blue 1(Color Index No.42045), Acid Red 184(Color Index No.15685), Acid Red 35(Color Index No.18065), Acid Red 14(Color Index No.14720), Food Red 6(Color Index No.16155), Acid Orange 3(Color Index No.10385), Acid Orange 24(Color Index No.20170), Acid Violet 43(Color Index No.60730), Acid Blue 62(Color Index No.62045), Acid Red 88(Color Index No.15620)、Acid Yellow 11(Color Index No.18820)、Acid Yellow 36(Color Index No.13065)、Acid Yellow 1(Color Index No.10316)、Acid Orange 7(Color Index No.15510)、Acid Orange 20(Color Index No.14600)、Acid Orange 6(Color Index No.14270)、Food Red 17(Color Index No.16035)、Acid Red 41(Color Index No.16290)、Acid Red 1(Color Index No.18050)、Acid Red 155(Color Index No.18130)、Acid Red 180(Color Index No.18736)、Acid Yellow 17(Color Index No.18965)、Acid Yellow 23(Color Index No.19140)、Acid Red 163(Color Index No.24790)、Food Black 2(Color Index No.27755)、Direct Orange 39(Color Index No.40215)、Acid Blue 7(Color Index No.42080)、Acid Green 9(Color Index No.42100)、Acid Green 22(Color Index No.42170)、Acid Blue 104(Color Index No.42735)、Acid Violet 9(Color Index No.45190)、Acid Red 50(Color Index No.45220)、Acid Violet 50(Color Index No.50325)、Acid Black 2(Color Index No.50420)、Acid Blue 80(Color Index No.61585)、Acid Blue 87(Color Index No.74180)、Acid Red 195(Color Index No.18760)、Acid Red 249(Color Index No.The color may include one or more selected from the group consisting of Acid Red 131, Acid Red 337 (Color Index No. 17102), Acid Red 18134, Acid Red 131, and Acid Red 337 (Color Index No. 17102).

[0204] Acid dye (C) is more preferably Acid Black 52 (Color Index No. 15711), Acid Green 1 (Color Index No. 10020), Food Black 1 (Color Index No. 28440), Food Green 3 (Color Index No. 42053), Acid Green 5 (Color Index No. 42095), Acid Blue 9 (Color Index). No.42090), Acid Blue 5(Color Index No.42052), Acid Green 3(Color Index No.42085), Acid Green 25(Color Index No.61570), Acid Brown 13(Color Index No.10410), Acid Red 52(Color Index No.45100), Acid Black 1(Color Index No.20470), Acid Red 18(Color Index No.16255), Acid Red 27(Color Index No. 16185), Acid Blue 3 (Color Index No. 42051), Acid Green 50 (Color Index No. 44090), Acid Red 73 (Color Index No. 27290), Acid Blue 1 (Color Index No. 42045), Acid Blue 7 (Color Index No. 42080), Acid Green 9 (Color Index No. 42100), Acid Blue 104 (Color Index No. 42735), and Acid Violet 50 (Color Index No. 50325).

[0205] Among the above, from the viewpoint of improving the durability of the modified regenerated collagen fibers, the acid dye (C) preferably includes one or more dyes selected from the group consisting of Food Green 3 (Color Index No. 42053), Acid Green 5 (Color Index No. 42095), Acid Blue 9 (Color Index No. 42090), Acid Blue 5 (Color Index No. 42052), Acid Green 3 (Color Index No. 42085), Acid Red 52 (Color Index No. 45100), Acid Blue 3 (Color Index No. 42051), Acid Green 50 (Color Index No. 44090), and Acid Blue 1 (Color Index No. 42045), which have a cationic moiety number (b) of 1 or more, and even more preferably includes one or more dyes selected from the group consisting of Acid Blue 9 and Acid Red 52.

[0206] [Basic dyes] As the basic dye, any known basic dye can be used without particular limitation, but from the viewpoint of improving the dyeability and fastness of the modified regenerated collagen fiber, the basic dye preferably includes a basic dye (D) (hereinafter simply referred to as "basic dye (D)") in which the value obtained by dividing the number of cationic moieties (a) by Mw [(a) / Mw] is 0.00275 or more, where Mw is the molecular weight. Because the number of cationic moieties (a) per molecular weight of the basic dye (D) is a predetermined value or more, it is thought that this enhances the electrical interaction with component (X) in the modified regenerated collagen fiber, thereby improving the dyeability. Examples of the cationic moiety include quaternary ammonium cationic moieties, imidazolium cationic moieties, pyridinium cationic moieties, pyrrolidinium cationic moieties, piperidinium cationic moieties, iminium cationic moieties, and pyrylium cationic moieties. From the viewpoint of improving the dyeability of the modified regenerated collagen fiber, it preferably contains an imidazolium cationic moiety or a pyridinium cationic moiety.

[0207] From the viewpoint of improving fastness, the molecular weight Mw of the basic dye (D) is preferably 200 or more, more preferably 220 or more, even more preferably 240 or more, and still more preferably 250 or more, and from the viewpoint of improving dyeability, it is preferably 500 or less, more preferably 450 or less, even more preferably 400 or less, still more preferably 360 or less, and still more preferably 340 or less. The molecular weight Mw of the basic dye (D) is preferably 200 or more and 500 or less, more preferably 220 or more and 450 or less, even more preferably 240 or more and 400 or less, still more preferably 250 or more and 360 or less, and still more preferably 250 or more and 340 or less. In this specification, the molecular weight of a basic dye means a state in which the dye has chloride as a counter ion and the charge is neutralized, that is, the molecular weight of the chloride.

[0208] The number (a) of cationic moieties in the basic dye (D) may be 1 or more, and is preferably 5 or less, more preferably 4 or less, even more preferably 3 or less, and still more preferably 2 or less. The number (a) of cationic moieties in the basic dye (D) is preferably 1 or more and 5 or less, more preferably 1 or more and 4 or less, even more preferably 1 or more and 3 or less, still more preferably 1 or more and 2 or less, and still more preferably 1.

[0209] Furthermore, when the molecular weight of the basic dye (D) is Mw, the value obtained by dividing the number of cationic sites (a) by Mw [(a) / Mw] is 0.00275 or more, preferably 0.00280 or more, and even more preferably 0.00290 or more, from the viewpoint of improving dyeability, and is preferably 0.010 or less, more preferably 0.008 or less, even more preferably 0.006 or less, even more preferably 0.005 or less, and even more preferably 0.004 or less. When the molecular weight of the basic dye (D) is Mw, the value obtained by dividing the number of cationic moieties (a) by Mw [(a) / Mw] is 0.00275 or more, preferably 0.00275 or more and 0.010 or less, more preferably 0.00275 or more and 0.008 or less, even more preferably 0.00275 or more and 0.006 or less, still more preferably 0.00275 or more and 0.005 or less, still more preferably 0.00280 or more and 0.005 or less, and still more preferably 0.00290 or more and 0.004 or less.

[0210] From the viewpoint of improving dyeability, the basic dye (D) preferably includes one or more dyes selected from the group consisting of Basic Red 51, Basic Yellow 87, Basic Orange 31, Basic Blue 124, Basic Brown 16 (Color Index No. 12250), Basic Violet 14 (Color Index No. 42510), Basic Black 7 (Color Index No. 51215), Basic Blue 25 (Color Index No. 52025), Basic Blue 6 (Color Index No. 51175), Basic Red 2 (Color Index No. 50240), Basic Red 22 (Color Index No. 11055), Basic Blue 17 (Color Index No. 52040), and Basic Blue 9 (Color Index No. 52015), and more preferably includes one or more dyes selected from the group consisting of Basic Red 51, Basic Yellow 87, Basic Orange 31, Basic Blue 124, and Basic Brown. 16, more preferably at least one selected from the group consisting of Basic Red 51, Basic Yellow 87, Basic Orange 31, and Basic Blue 124, and even more preferably at least one selected from the group consisting of Basic Red 51, Basic Yellow 87, and Basic Orange 31.

[0211] When the dye used in hair dye B is one or more dyes selected from the group consisting of acid dyes and basic dyes, hair dye B is preferably a one-component hair dye. The one-component hair dye contains one or more dyes selected from the group consisting of acid dyes and basic dyes, and water.

[0212] The dye content in hair dye B (in the case of the multi-component hair dye, hair dye B prepared by mixing the first and second components at the time of use) is preferably 0.005% by mass or more, more preferably 0.01% by mass or more, even more preferably 0.02% by mass or more, even more preferably 0.03% by mass or more, even more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more, and even more preferably 0.2% by mass or more, from the viewpoint of improving dyeability, and is preferably 3% by mass or less, more preferably 2% by mass or less, and even more preferably 1% by mass or less, from the viewpoint of improving formulation stability. The content of the dye in hair dye B is preferably 0.005% by mass or more and 3% by mass or less, more preferably 0.01% by mass or more and 3% by mass or less, even more preferably 0.02% by mass or more and 3% by mass or less, even more preferably 0.03% by mass or more and 3% by mass or less, even more preferably 0.05% by mass or more and 3% by mass or less, even more preferably 0.1% by mass or more and 2% by mass or less, and even more preferably 0.2% by mass or more and 1% by mass or less. From the viewpoint of improving handleability, the water content in hair dye B is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 85% by mass or more, and is preferably 99.995% by mass or less.

[0213] In addition to the above components, hair dye B may contain antioxidants, fragrances, preservatives, thickeners, pH adjusters, surfactants, texture improvers, etc., within limits that do not impair the effects of the present invention. The formulation of hair dye B is not particularly limited, and can be in the form of liquid, paste, cream, gel, foam, spray, wax, or the like depending on the product form, with liquid being preferred. Hair dye B can be produced according to a conventional method.

[0214] (Dyeing method) There are no particular limitations on the method for dyeing hair with hair dye B, and conventional methods can be used. When using a commercially available hair dye, it is preferable to dye the hair according to the method described in the instructions attached to the product.

[0215] <Process (III)> In step (III), the hair and the fiber for head accessories are kept in contact with each other and kept wet. By performing this step, the dye from the hair dyed with hair dye B is transferred to the fiber for head accessories containing the modified regenerated collagen fiber, thereby improving the color matching effect. The fiber for head accessories to be subjected to step (III) is a fiber for head accessories containing the modified regenerated collagen fiber after the treatment in step (I).

[0216] The term "wet state" as used here refers to the state of the hair and the fiber for head accessories after a process for increasing the moisture content of the hair and the fiber for head accessories. The water content in the fiber for head accessories and the hair is not particularly limited, but when the weight of the fiber for head accessories after conditioning for 24 hours at 20°C and a relative humidity of 65% is taken as 1, the water content in the fiber for head accessories, expressed as a mass ratio (water / fiber for head accessories), is preferably 0.05 or more, more preferably 0.10 or more, even more preferably 0.2 or more, still more preferably 0.3 or more, still more preferably 0.5 or more, still more preferably 0.7 or more, and still more preferably 1.0 or more, from the viewpoint of improving color matching, and the water content in the fiber for head accessories is preferably 5 or less, more preferably 3 or less, and even more preferably 2 or less, from the viewpoint of easy handling. The water content in the fiber for head accessories in a wet state is preferably a mass ratio (water / fiber for head accessories) of 0.05 or more and 5 or less, more preferably 0.10 or more and 5 or less, even more preferably 0.2 or more and 5 or less, still more preferably 0.3 or more and 5 or less, still more preferably 0.5 or more and 3 or less, still more preferably 0.7 or more and 2 or less, and still more preferably 1.0 or more and 2 or less, where the mass of the fiber for head accessories after conditioning at 20°C and a relative humidity of 65% for 24 hours is taken as 1. The method for moistening the hair and the fiber for a head accessory is not particularly limited, and examples thereof include (i) immersing the hair in water, (ii) rinsing with water, (iii) washing with a hair wash composition, (iv) treating with a rinse-off conditioner or treatment and then rinsing with water, (v) spraying or misting the hair with a water-containing spray, (vi) applying steam, (vii) wrapping with a wet towel, or (vii) wrapping in plastic wrap, aluminum foil, or the like while wet with water, and one or more of these methods can be used.

[0217] Among the above, from the viewpoint of ease of processing and improving the color compatibility between the hair and the fiber for a head accessory containing modified regenerated collagen fibers, step (III) preferably includes one or more methods selected from the group consisting of (ii) a method of rinsing the hair to which the head accessory is attached with water, and (iii) a method of washing the hair with a hair wash composition, and more preferably includes a step of washing the hair and the fiber for a head accessory with a hair wash composition, followed by rinsing with water. The water referred to here may be water at room temperature (5° C. or higher and 35° C. or lower) or warm water above 35° C. The hair wash composition used in step (III) is not particularly limited, and a commercially available product may be used.

[0218] In step (III), the time for keeping the hair and the fiber for a head accessory in a wet state is not particularly limited and can be appropriately selected depending on the method for keeping the hair and the fiber for a head accessory in a wet state. From the viewpoint of improving the color compatibility between the hair and the fiber for a head accessory, the time is preferably 1 second or more, more preferably 5 seconds or more, and from the viewpoint of reducing the burden on the hairdresser and the patient, the time is preferably 6 hours or less, more preferably 3 hours or less, and even more preferably 2 hours or less. In step (III), the temperature at which the hair and the fiber for a head accessory are moistened is not particularly limited and can be appropriately selected depending on the method for moistening. From the viewpoint of improving the color matching effect between the hair and the fiber for a head accessory containing regenerated collagen fibers, the time is preferably above 0°C, more preferably 5°C or higher, and from the viewpoint of reducing the burden on the hairdresser and the patient, the time is preferably 100°C or lower. The temperature here refers to the temperature of the water used to moisten the hair.

[0219] After step (III), it is preferable to carry out a step of drying the head accessory and the hair to which it is attached (hereinafter simply referred to as the "drying step"). The drying step is a step of reducing the moisture content of the head accessory and the hair to which it is attached. The water content in the head accessory fiber and hair after drying is not particularly limited, but the water content in the head accessory fiber is preferably a mass ratio (water / head accessory fiber) of 0.8 or less, more preferably 0.7 or less, even more preferably 0.5 or less, even more preferably 0.3 or less, even more preferably 0.2 or less, even more preferably 0.1 or less, and even more preferably less than 0.1, when the weight of the head accessory fiber after conditioning at 20°C and 65% relative humidity for 24 hours is taken as 1. Drying methods include, for example, towel drying, drying with a hair dryer (cold air or hot air), air drying, and combinations of two or more of these drying processes.

[0220] [Fiber treatment kit for headwear products] The present invention further provides a treatment kit for fibers for head accessories, comprising a treatment composition A for treating fibers for head accessories containing regenerated collagen fibers, and a hair dye B for dyeing hair, The treatment composition A contains a compound (A) having a pKa value of 1 or more and 7 or less, and water, and has a pH of 2 or more and 6 or less, The regenerated collagen fiber is a modified regenerated collagen fiber containing the following component (X), and a fiber treatment kit for head accessories is provided. (X) A copolymer containing a structural unit derived from an unsaturated monomer having a carboxy group and a structural unit derived from an aromatic vinyl compound, the copolymer having an acid value of 100 mgKOH / g or more and a weight average molecular weight of 1500 or more and 15000 or less, or a salt thereof.

[0221] The treatment composition A and its preferred embodiments in the fiber treatment kit for head accessories are the same as the treatment composition A used in step (I) above, and the hair dye B and its preferred embodiments are the same as the hair dye B used in dyeing the hair above.

[0222] The fiber treatment kit for head accessories can be used, for example, in the following manner. First, hair is dyed with hair dye B. Meanwhile, a fiber for a head accessory is treated with treatment composition A according to step (I), and a head accessory containing the fiber for a head accessory is attached to the hair according to step (II). Next, according to step (III), the hair and the treated fiber for a head accessory are kept in contact with each other and kept in a wet state. Alternatively, the hair is dyed with hair dye B, and according to the step (II), a head accessory containing a head accessory fiber before treatment with treatment composition A is attached to the hair. Next, according to the step (I), the head accessory fiber is treated with treatment composition A. Furthermore, according to the step (III), the hair and the treated head accessory fiber are kept in contact with each other in a wet state. By using the fiber treatment kit for head accessories of the present invention in the above-described manner, it is possible to improve the underwater elastic modulus of the fiber for head accessories containing specific modified regenerated collagen fibers, reduce the color difference between the hair and the fiber for head accessories, and improve the color matching effect.

[0223] [use] The present invention further provides a use of composition A as a fiber treatment composition for head accessories containing regenerated collagen fibers, comprising: The composition A contains a compound (A) having a pKa value of 1 or more and 7 or less, and water, and has a pH of 2 or more and 6 or less, The regenerated collagen fibers contain the following component (X): (X) A copolymer containing a structural unit derived from an unsaturated monomer having a carboxy group and a structural unit derived from an aromatic vinyl compound, the copolymer having an acid value of 100 mgKOH / g or more and a weight average molecular weight of 1500 or more and 15000 or less, or a salt thereof. The modified regenerated collagen fiber contains The method for treating the fiber for head accessories with the composition A comprises the following steps (I) to (III): The present invention provides a use of composition A, which comprises the following step (III) after the steps (I) and (II): Step (I) applying the composition A to the fiber for head accessories. Step (II) A step of attaching a head accessory containing the fiber for a head accessory to hair dyed with hair dye B. Step (III): A step of keeping the hair and the fiber for head accessories in a wet state while the hair and the fiber for head accessories are in contact with each other.

[0224] The composition A and its preferred embodiments are the same as those of the treatment composition A, and the modified regenerated collagen fibers, steps (I) to (III) and their preferred embodiments are also the same as those described above. That is, compound (A) in composition A preferably contains a compound that satisfies at least one of the following (1) and (2), and more preferably contains one or more compounds selected from the group consisting of surfactants that satisfy the following (1), polymers that satisfy the following (2), and carboxylic acid compounds (excluding surfactants) that have a molecular weight of less than 1,500 and that satisfy the following (1). (1) Al 3+ Chelate stability constant logK with ions is 2 or less (2) Molecular weight of 1500 or more Furthermore, the compound (A) preferably has one or more acidic groups selected from the group consisting of a carboxy group and a sulfate group.

[0225] The compound (A) used in composition A preferably contains one or more compounds selected from the group consisting of surfactants, polymers, and carboxylic acid compounds (excluding surfactants) having a molecular weight of less than 1500, each of which has one or more acidic groups selected from the group consisting of a carboxy group and a sulfate group; more preferably, it contains one or more compounds selected from the group consisting of surfactants satisfying the above (1), polymers satisfying the above (2), and carboxylic acid compounds (excluding surfactants) having a molecular weight of less than 1500, and even more preferably, it contains one or more compounds selected from the group consisting of alkyl sulfates, alkyl ether sulfates, alkyl ether carboxylates, N-acylamino acid salts, fatty acid amidopropyl betaine, anionic vinyl polymers containing structural units derived from (meth)acrylic acid, anionic polysaccharides, amphoteric polymers containing structural units derived from (meth)acrylic acid, amphoteric polymers containing a betaine group, and carboxylic acid compounds (excluding surfactants) having a molecular weight of less than 1500; and even more preferably, it contains one or more compounds selected from the group consisting of sodium lauryl sulfate, ammonium lauryl sulfate, polyoxyethylene lauryl ether sulfate, polyoxyethylene lauryl ether acetate, N-lauroyl the hydroxybenzoate, ...It contains one or more selected from the group consisting of polyacrylic acid, xanthan gum, acrylamide-acrylic acid-dimethyldiallylammonium chloride copolymer (polyquaternium-39), 2-pyrrolidone-5-carboxylic acid, and pyruvic acid, and even more preferably contains one or more selected from the group consisting of polyoxyethylene (3) lauryl ether sodium sulfate, polyoxyethylene (10) lauryl ether acetate, N-lauroylmethylalanine sodium, lauric acid amidopropyl betaine, polyacrylic acid (molecular weight 5000), polyacrylic acid (molecular weight 25000), xanthan gum, acrylamide-acrylic acid-dimethyldiallylammonium chloride copolymer (polyquaternium-39), 2-pyrrolidone-5-carboxylic acid, and pyruvic acid.

[0226] With respect to the above-mentioned embodiments, the present invention discloses the following. <1> A method for treating fibers for headwear products containing regenerated collagen fibers, comprising: The regenerated collagen fibers contain the following component (X): (X) A copolymer containing a structural unit derived from an unsaturated monomer having a carboxy group and a structural unit derived from an aromatic vinyl compound, the copolymer having an acid value of 100 mgKOH / g or more and a weight average molecular weight of 1500 or more and 15000 or less, or a salt thereof. The modified regenerated collagen fiber contains The method comprises the following steps (I) to (III): A method for treating fibers for head accessories, comprising the following step (III) after the steps (I) and (II). Step (I): A step of applying a treatment composition A containing a compound (A) having a pKa value of 1 or more and 7 or less and water and having a pH of 2 or more and 6 or less to the fiber for headwear. Step (II) A step of attaching a head accessory containing the fiber for a head accessory to hair dyed with hair dye B. Step (III): A step of keeping the hair and the fiber for head accessories in a wet state while the hair and the fiber for head accessories are in contact with each other. <2> The head accessory product includes a hair wig, a toupee, a weaving, a hair extension, a braided hair, a hair accessory, or a doll hair, preferably includes one or more selected from the group consisting of a hair wig, a toupee, a weaving, and a hair extension, more preferably includes a hair extension; <1> How to process. <3> the component (X) comprises a copolymer containing structural units derived from one or more selected from the group consisting of unsaturated monocarboxylic acids and unsaturated dicarboxylic acids and structural units derived from an aromatic vinyl compound, preferably one or more selected from the group consisting of styrene-maleic acid copolymer, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, vinylbenzoic acid-maleic acid copolymer, vinylbenzoic acid-acrylic acid copolymer, vinylbenzoic acid-methacrylic acid copolymer, and styrene-4-vinylbenzoic acid copolymer, more preferably a styrene-maleic acid copolymer; <1> or <2> How to process. <4> In the component (X), the molar ratio (u1 / u2) of the structural unit (u1) derived from the unsaturated monomer having a carboxy group to the structural unit (u2) derived from the aromatic vinyl compound monomer is preferably 1 / 5 to 5 / 1, more preferably 1 / 3 to 3 / 1, and even more preferably 1 / 2 to 2 / 1. <1> ~ <3> Either one of the following processing methods. <5> The acid value of the component (X) is preferably 100 mgKOH / g or more and 1000 mgKOH / g or less, more preferably 200 mgKOH / g or more and 800 mgKOH / g or less, even more preferably 200 mgKOH / g or more and 600 mgKOH / g or less, still more preferably 300 mgKOH / g or more and 600 mgKOH / g or less, and still more preferably 400 mgKOH / g or more and 600 mgKOH / g or less. <1> ~ <4> Either one of the following processing methods. <6> The weight average molecular weight of the component (X) is preferably 3,000 or more and 15,000 or less, more preferably 5,000 or more and 15,000 or less, even more preferably 6,000 or more and 15,000 or less, and still more preferably 6,000 or more and 10,000 or less. <1> ~ <5> Either one of the following processing methods. <7> The content of component (X) in the modified regenerated collagen fibers is preferably 0.1% by mass or more and 70% by mass or less, more preferably 0.5% by mass or more and 65% by mass or less, even more preferably 1.0% by mass or more and 60% by mass or less, still more preferably 3.0% by mass or more and 55% by mass or less, even more preferably 5.0% by mass or more and 50% by mass or less, still more preferably 10% by mass or more and 45% by mass or less, still more preferably 15% by mass or more and 40% by mass or less, and still more preferably 20% by mass or more and 40% by mass or less, <1> ~ <6> Either one of the following processing methods. <8> The modified regenerated collagen fibers further contain a polyvalent metal, a salt thereof, or a complex thereof as component (Y). <1> ~ <7> Either one of the following processing methods. <9> the component (Y) comprises one or more polyvalent metals selected from the group consisting of calcium, magnesium, strontium, barium, zinc, chromium, aluminum, titanium, zirconium, tin, lead, antimony, iron, and copper, or salts thereof, or complexes thereof, preferably one or more polyvalent metals selected from the group consisting of aluminum, zirconium, and titanium, or salts thereof, or complexes thereof, and more preferably aluminum, or salts thereof, or complexes thereof; <8> How to process. <10> The content of component (Y) in the modified regenerated collagen fibers is preferably 0.1% by mass or more and 40% by mass or less, more preferably 0.5% by mass or more and 30% by mass or less, even more preferably 1.0% by mass or more and 20% by mass or less, and even more preferably 2.0% by mass or more and 10% by mass or less, in terms of the amount of metal elements. <8> or <9> How to process.

[0227] <11> The fibers for headwear products subjected to the treatment method are preferably colored. <1> ~ <10> Either one of the following processing methods. <12> The treatment method is either (1) a method having the steps (I), (II), and (III) in this order, or (2) a method having the steps (II), (I), and (III) in this order, and preferably (1) a method having the steps (I), (II), and (III) in this order. <1> ~ <11> Either one of the following processing methods. <13> In the method (1), a rinsing step is preferably included between the step (I) and the step (II). <12> How to process. <14> The pKa of the compound (A) is preferably 1.5 or more and 6 or less, more preferably 2.0 or more and 5 or less, and even more preferably 2.5 or more and 4 or less. <1> ~ <13> Either one of the following processing methods. <15> The pKa of the compound (A) is preferably −3.0 or more and +3.0 or less, more preferably −2.0 or more and +2.0 or less, and even more preferably −1.0 or more and +1.0 or less, relative to the pH value of the treatment composition A. <1> ~ <14> Either one of the following processing methods. <16> The solubility of the compound (A) in 100 g of water at pH 3 and 25°C is preferably 2.5 g or more, more preferably 5 g or more, even more preferably 10 g or more, and preferably 100 g or less. <1> ~ <15> Either one of the following processing methods. <17> The number of phenolic hydroxyl groups in the compound (A) is preferably 1 or less, more preferably 0. <1> ~ <16> Either one of the following processing methods. <18> When the compound (A) satisfies the above (1), Al of the compound (A) 3+The chelate stability constant logK with an ion is preferably 1.8 or less, more preferably 1.6 or less, even more preferably 1.4 or less, still more preferably 1.2 or less, even more preferably 1.0 or less, and still more preferably 0.5 or less. <1> ~ <17> Either one of the following processing methods. <19> When the compound (A) satisfies the above (2), the molecular weight of the compound (A) is preferably 2,000 or more and 100,000,000 or less, more preferably 3,000 or more and 50,000,000 or less, even more preferably 3,000 or more and 5,000,000 or less, still more preferably 3,000 or more and 2,000,000 or less, still more preferably 3,000 or more and 100,000 or less, still more preferably 3,000 or more and 50,000 or less, still more preferably 3,000 or more and 10,000 or less, still more preferably 4,000 or more and 10,000 or less. <1> ~ <18> Either one of the following processing methods. <20> The compound (A) preferably contains a compound having an acidic group, more preferably contains a compound having one or more acidic groups selected from the group consisting of a carboxy group, a sulfate group, a sulfonic acid group, and a phosphate group, even more preferably contains a compound having one or more acidic groups selected from the group consisting of a carboxy group and a sulfate group, and even more preferably contains a compound having a carboxy group. <1> ~ <19> Either one of the following processing methods.

[0228] <21> When the compound (A) has a molecular weight of less than 1,500, the number of acidic groups in the compound (A) is preferably 1 or more and 50 or less, more preferably 1 or more and 20 or less, even more preferably 1 or more and 10 or less, and still more preferably 1 or more and 4 or less. <1> ~ <20> Either one of the following processing methods. <22> The compound (A) preferably includes at least one selected from the group consisting of surfactants, polymers, and carboxylic acid compounds (excluding surfactants) having an acidic group and having a molecular weight of less than 1,500. <20> or <21> How to process. <23> The surfactant used as the compound (A) preferably satisfies the above (1) and includes at least one selected from the group consisting of anionic surfactants and amphoteric surfactants. <22> How to process. <24> The anionic surfactant preferably comprises one or more selected from the group consisting of sulfate ester-type anionic surfactants and carboxylic acid-type anionic surfactants, more preferably comprises one or more selected from the group consisting of alkyl or alkenyl sulfate salts, alkyl or alkenyl ether sulfate salts, saturated or unsaturated fatty acid salts, alkyl or alkenyl ether carboxylate salts, and N-acylamino acid salts, and even more preferably comprises one or more selected from the group consisting of alkyl sulfate salts, alkyl ether sulfate salts, alkyl ether carboxylate salts, and N-acylamino acid salts. <23> How to process. <25> The amphoteric surfactant preferably comprises one or more selected from the group consisting of an amine oxide amphoteric surfactant, a carboxybetaine amphoteric surfactant, and a sulfobetaine amphoteric surfactant, more preferably comprises a carboxybetaine amphoteric surfactant, and even more preferably comprises a fatty acid amidopropyl betaine; <23> How to process. <26> The surfactant used as the compound (A) preferably satisfies the above (1) and contains at least one selected from the group consisting of sulfate ester-type anionic surfactants, carboxylic acid-type anionic surfactants, amine oxide-type amphoteric surfactants, carboxybetaine-type amphoteric surfactants, and sulfobetaine-type amphoteric surfactants, more preferably at least one selected from the group consisting of alkyl or alkenyl sulfates, alkyl or alkenyl ether sulfates, saturated or unsaturated fatty acid salts, alkyl or alkenyl ether carboxylates, N-acylamino acid salts, and carboxybetaine-type amphoteric surfactants, and even more preferably at least one selected from the group consisting of alkyl or alkenyl sulfates, alkyl or alkenyl ether sulfates, saturated or unsaturated fatty acid salts, alkyl or alkenyl ether carboxylates, N-acylamino acid salts, and carboxybetaine-type amphoteric surfactants. and more preferably, the surfactant contains at least one selected from the group consisting of sodium lauryl sulfate, ammonium lauryl sulfate, polyoxyethylene lauryl ether sulfate, polyoxyethylene lauryl ether acetate, sodium N-lauroylmethylalanine, lauric acid amidopropyl betaine [lauramidopropyl betaine], palm kernel oil fatty acid amidopropyl betaine, and coconut oil fatty acid amidopropyl betaine [cocamidopropyl betaine]. <22> ~ <25> Either one of the following processing methods. <27> The polymer used as the compound (A) is a polymer other than the component (X), and preferably contains one or more polymers selected from the group consisting of anionic polymers and amphoteric polymers that satisfy the above (2). <22> ~ <26> Either one of the following processing methods. <28> The anionic polymer preferably contains one or more selected from the group consisting of anionic vinyl polymers containing structural units derived from (meth)acrylic acid and anionic polysaccharides. <27> How to process. <29> The anionic vinyl polymer containing a structural unit derived from (meth)acrylic acid contains at least one selected from the group consisting of a (meth)acrylic acid homopolymer and an anionic (meth)acrylic acid copolymer. <28> How to process. <30> The (meth)acrylic acid homopolymer contains one or more selected from the group consisting of polyacrylic acid and polymethacrylic acid. <29> How to process.

[0229] <31> the anionic (meth)acrylic acid copolymer comprises one or more selected from the group consisting of (meth)acrylic acid / maleic acid copolymer, (meth)acrylic acid / itaconic acid copolymer, (meth)acrylic acid / fumaric acid copolymer, (meth)acrylic acid / vinyl acetate copolymer, (meth)acrylic acid / (meth)acrylic acid alkyl ester copolymer, (meth)acrylic acid / 2-hydroxyethyl methacrylate copolymer, acrylic acid / acrylic acid alkyl ester / (N-alkyl)acrylamide copolymer, carboxyvinyl polymer, (acrylates / alkyl acrylate (C10-30)) crosspolymer, (sodium acrylate / acryloyldimethyltaurine / dimethylacrylamide) crosspolymer, and acrylates crosspolymer-4; <29> How to process. <32> The anionic polysaccharide used as the compound (A) includes at least one selected from the group consisting of polysaccharides having a carboxy group and sulfates of polysaccharides. <28> ~ <31> Either one of the following processing methods. <33> The polysaccharide having a carboxy group includes one or more selected from the group consisting of hyaluronic acid, alginic acid, pectinic acid, carboxymethylcellulose, and xanthan gum, and the sulfated polysaccharide includes one or more selected from the group consisting of carrageenan, keratan sulfate, dermatan sulfate, sulfated starch, heparin, and heparan sulfate. <32> How to process. <34> The anionic polysaccharide preferably comprises one or more selected from the group consisting of carboxymethyl cellulose, xanthan gum, and carrageenan, and more preferably comprises xanthan gum. <28> ~ <33> Either one of the following processing methods. <35> The anionic polymer used as the compound (A) preferably contains one or more selected from the group consisting of polyacrylic acid and anionic polysaccharides, more preferably contains one or more selected from the group consisting of polyacrylic acid, carboxymethyl cellulose, xanthan gum, and carrageenan, and even more preferably contains polyacrylic acid. <27> ~ <34> Either one of the following processing methods. <36> The amphoteric polymer used as the compound (A) is a copolymer of methacryloylethyldimethylbetaine, methacryloylethyltrimethylammonium chloride, and methoxypolyethylene glycol methacrylate (Polyquaternium-49), a copolymer of methacryloylethyldimethylbetaine, methacryloylethyltrimethylammonium chloride, and 2-hydroxyethyl methacrylate (Polyquaternium-48), a copolymer of vinylpyrrolidone and N,N-dimethylaminoethyl diethyl methacrylate sulfate (Polyquaternium-11), a copolymer of N,N-dimethylaminoethyl diethyl methacrylate sulfate and N,N-dimethylaminoethyl diethyl methacrylate sulfate (Polyquaternium-12), a copolymer of vinylpyrrolidone and N,N-dimethylaminoethyl diethyl methacrylate sulfate (Polyquaternium-13), a copolymer of vinylpyrrolidone and N,N-dimethylaminoethyl diethyl methacrylate sulfate (Polyquaternium-14), a copolymer of vinylpyrrolidone and N,N-dimethylaminoethyl diethyl methacrylate sulfate (Polyquaternium-15), a copolymer of vinylpyrrolidone and N,N-dimethylaminoethyl diethyl methacrylate sulfate (Polyquaternium-16), a copolymer of vinylpyrrolidone and N,N-dimethylaminoethyl diethyl methacrylate sulfate (Polyquaternium-17), a copolymer of vinylpyrrolidone and N,N-dimethylaminoethyl diethyl methacrylate sulfate (Polyquaternium-18), a copolymer of vinylpyrrolidone and N,N-dimethylaminoethyl diethyl methacrylate sulfate (Polyquaternium-19), a copolymer of vinylpyrrolidone and N,N-dimethylaminoethyl diethyl methacrylate sulfate (Polyquaternium-20), a copolymer of vinylpyrrolidone and N,N-dimethylaminoethyl diethyl methacrylate sulfate (Polyquaternium-21), a copolymer of vinylpyrrolidone and N,N-dimethylaminoethyl diethyl methacrylate sulfate (Polyquaternium-22), a copolymer The copolymer comprises at least one selected from the group consisting of methylacrylamide-polyethylene glycol dimethacrylate copolymer (Polyquaternium-52), dimethyldiallylammonium chloride-acrylic acid copolymer (Polyquaternium-22), acrylic acid-dimethyldiallylammonium chloride-acrylamide copolymer (Polyquaternium-39), acrylic acid-methyl acrylate-methacrylamidopropyltrimethylammonium chloride copolymer (Polyquaternium-47), and acrylic acid-acrylamide-methacrylamidopropyltrimethylammonium chloride copolymer (Polyquaternium-53), <27> ~ <35> Either one of the following processing methods. <37> The amphoteric polymer used as the compound (A) preferably contains one or more structural units selected from the group consisting of structural units derived from (meth)acrylic acid and betaine groups, more preferably contains a structural unit derived from (meth)acrylic acid, even more preferably contains one or more structural units selected from the group consisting of dimethyldiallylammonium chloride-acrylic acid copolymer (Polyquaternium-22), acrylamide-acrylic acid-dimethyldiallylammonium chloride copolymer (Polyquaternium-39), acrylic acid-methyl acrylate-methacrylamidopropyltrimethylammonium chloride copolymer (Polyquaternium-47), and acrylic acid-acrylamide-methacrylamidopropyltrimethylammonium chloride copolymer (Polyquaternium-53), and even more preferably contains acrylic acid-dimethyldiallylammonium chloride-acrylamide copolymer (Polyquaternium-39). <27> ~ <35> Either one of the following processing methods. <38> The polymer used as the compound (A) preferably satisfies the above (2) and contains at least one selected from the group consisting of anionic vinyl polymers containing structural units derived from (meth)acrylic acid, anionic polysaccharides, amphoteric polymers containing structural units derived from (meth)acrylic acid, and amphoteric polymers containing a betaine group, more preferably at least one selected from the group consisting of anionic vinyl polymers containing structural units derived from (meth)acrylic acid, anionic polysaccharides, and amphoteric polymers containing structural units derived from (meth)acrylic acid, and even more preferably polyacrylic acid, carboxymethylcellulose, xanthan gum, carrageenan, dimethyldiallylammonium chloride, acrylic acid, the copolymer of acrylic acid and acrylic acid and dimethyldiallylammonium chloride (Polyquaternium-22), the copolymer of acrylic acid and acrylic acid and dimethyldiallylammonium chloride (Polyquaternium-39), the copolymer of acrylic acid and methyl acrylate and methacrylamidopropyltrimethylammonium chloride (Polyquaternium-47), and the copolymer of acrylic acid and acrylamide and methacrylamidopropyltrimethylammonium chloride (Polyquaternium-53), and more preferably the copolymer of acrylic acid and acrylic acid and dimethyldiallylammonium chloride (Polyquaternium-39), <22> ~ <37> Either one of the following processing methods. <39> The carboxylic acid compound (excluding surfactants) having a molecular weight of less than 1,500 includes at least one selected from the group consisting of 2-pyrrolidone-5-carboxylic acid, pyruvic acid, proline, serine, glycine, leucine, arginine, glutamic acid, and histidine, and preferably includes at least one selected from the group consisting of 2-pyrrolidone-5-carboxylic acid and pyruvic acid. <22> ~ <38> Either one of the following processing methods. <40> The compound (A) preferably contains one or more selected from the group consisting of surfactants, polymers, and carboxylic acid compounds (excluding surfactants) having one or more acidic groups selected from the group consisting of a carboxy group and a sulfate group, more preferably one or more selected from the group consisting of surfactants satisfying the above (1), polymers satisfying the above (2), and carboxylic acid compounds (excluding surfactants) having a molecular weight of less than 1500 satisfying the above (1), even more preferably one or more selected from the group consisting of alkyl sulfates, alkyl ether sulfates, alkyl ether carboxylates, N-acylamino acid salts, fatty acid amidopropyl betaine, anionic vinyl polymers containing structural units derived from (meth)acrylic acid, anionic polysaccharides, amphoteric polymers containing structural units derived from (meth)acrylic acid, amphoteric polymers containing a betaine group, and carboxylic acid compounds (excluding surfactants) having a molecular weight of less than 1500, and even more preferably sodium lauryl sulfate, ammonium lauryl sulfate, polyoxyethylene lauryl ether sulfate, polyoxyethylene lauryl ether acetate, N-lauroylmethylalanine sodium sodium lauryl sulfate, ammonium lauryl sulfate, sodium polyoxyethylene lauryl ether sulfate, sodium polyoxyethylene lauryl ether acetate, sodium N-lauroylmethylalanine, sodium lauryl ether acetate, sodium polyoxyethylene lauryl ether acetate, sodium N-lauroylmethylalanine, sodium polyoxyethylene lauryl ether acetate ...The composition contains at least one selected from the group consisting of xanthan gum, acrylamide-acrylic acid-dimethyldiallylammonium chloride copolymer (polyquaternium-39), 2-pyrrolidone-5-carboxylic acid, and pyruvic acid, <1> ~ <39> Either one of the following processing methods:

[0230] <41> The content of compound (A) in the treatment composition A is preferably 0.01% by mass or more and 40% by mass or less, more preferably 0.05% by mass or more and 30% by mass or less, even more preferably 0.1% by mass or more and 25% by mass or less, still more preferably 0.2% by mass or more and 20% by mass or less, still more preferably 0.5% by mass or more and 20% by mass or less, still more preferably 1.0% by mass or more and 20% by mass or less, still more preferably 1.5% by mass or more and 15% by mass or less, and still more preferably 2.0% by mass or more and 10% by mass or less, <1> ~ <40> Either one of the following processing methods. <42> When the compound (A) contains a polymer, the content of the compound (A) in the treatment composition A is more preferably 5% by mass or more and 10% by mass or less, and even more preferably 7.5% by mass or more and 10% by mass or less. <22> ~ <41> Either one of the following processing methods. <43> The water content in the treatment composition A is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 75% by mass or more, and still more preferably 80% by mass or more, and is preferably 99.99% by mass or less. <1> ~ <42> Either one of the following processing methods. <44> The pH of the treatment composition A is preferably 3.0 or more and 6.0 or less, more preferably 3.5 or more and 6.0 or less, even more preferably 4.0 or more and 6.0 or less, and still more preferably 4.0 or more and 5.5 or less. <1> ~ <43> Either one of the following processing methods. <45> The treatment composition A is in the form of a liquid, mist, paste, cream, gel, foam, spray, or wax, and is preferably in the form of a liquid. <1> ~ <44> Either one of the following processing methods. <46> In the step (I), the method of applying the treatment composition A to the regenerated collagen fibers includes a method of applying the treatment composition A to the regenerated collagen fibers in a dry or wet state, or a method of immersing the regenerated collagen fibers in the treatment composition A, and preferably includes a method of immersing the regenerated collagen fibers in a dry state in the treatment composition A. <1> ~ <45> Either one of the following processing methods. <47> In the step (I), when the content of compound (A) in treatment composition A is c [mass%] and the amount of treatment composition A applied per 1 g of fiber is b [g], the total amount of compound (A) applied per 1 g of fiber, b × c / 100 [g], is preferably 0.01 g or more and 10 g or less, more preferably 0.03 g or more and 5 g or less, even more preferably 0.05 g or more and 3 g or less, and still more preferably 0.1 g or more and 1 g or less. <1> ~ <46> Either one of the following processing methods. <48> In step (I), the amount of treatment composition A applied to the regenerated collagen fibers is, when the mass of the fibers after conditioning at 20°C and a relative humidity of 65% for 24 hours is taken as the dry mass, a bath ratio (dry mass of regenerated collagen fibers:mass of treatment composition A) of preferably 1:0.2 to 1:500, more preferably 1:0.2 to 1:200, even more preferably 1:0.5 to 1:100, and still more preferably 1:0.5 to 1:50. <1> ~ <47> Either one of the following processing methods. <49> When the regenerated collagen fibers are immersed in the treatment composition A, the bath ratio (dry mass of the regenerated collagen fibers:mass of the treatment composition A) is more preferably 1:2 to 1:50, even more preferably 1:5 to 1:50, even more preferably 1:10 to 1:50, and even more preferably 1:10 to 1:40, when the mass of the fibers after conditioning for 24 hours at 20°C and a relative humidity of 65% is taken as the dry mass. <48> How to process. <50> When the treatment composition A is applied to the regenerated collagen fibers, the bath ratio (dry mass of the regenerated collagen fibers:mass of the treatment composition A) is more preferably 1:0.5 to 1:20, even more preferably 1:0.5 to 1:10, even more preferably 1:0.5 to 1:5, and even more preferably 1:0.5 to 1:3, when the mass of the fibers after conditioning for 24 hours at 20°C and a relative humidity of 65% is taken as the dry mass. <48> How to process.

[0231] <51> When the treatment composition A is applied to the regenerated collagen fibers, the application time is preferably 10 seconds or more and 10 minutes or less, more preferably 20 seconds or more and 5 minutes or less. <46> ~ <48> , <50> Either one of the following processing methods. <52> After applying the treatment composition A to the regenerated collagen fibers, a step of leaving the treatment composition A to stand is further carried out, and the standing time is preferably 1 minute or more and 1 hour or less, more preferably 3 minutes or more and 30 minutes or less, and even more preferably 5 minutes or more and 20 minutes or less. <46> ~ <48> , <50> ~ <51> Either one of the following processing methods. <53> When the regenerated collagen fibers are immersed in the treatment composition A, the immersion time is preferably 10 seconds or more and 3 hours or less, more preferably 10 seconds or more and 2 hours or less, and even more preferably 30 seconds or more and 90 minutes or less. <46> ~ <49> Either one of the following processing methods. <54> The temperature when the treatment composition A is applied to the regenerated collagen fibers is preferably 5°C or higher and 80°C or lower, more preferably 10°C or higher and 60°C or lower, even more preferably 20°C or higher and 50°C or lower, and still more preferably 30°C or higher and 50°C or lower. <1> ~ <53> Either one of the following processing methods. <55> a step of rinsing away excess treatment composition A applied to the regenerated collagen fibers after carrying out step (I) and before carrying out the next step; <1> ~ <54> Either one of the following processing methods. <56> a step of drying the regenerated collagen fibers after applying the treatment composition A to the regenerated collagen fibers, and after a rinsing step, if any, is performed; <1> ~ <55> Either one of the following processing methods. <57> The head accessory product to be attached to the hair in step (II) is a head accessory product containing the modified regenerated collagen fiber after the treatment in step (I), or a head accessory product containing the modified regenerated collagen fiber before the treatment in step (I), and is preferably a head accessory product containing the modified regenerated collagen fiber dyed after the treatment in step (I). <1> ~ <56> Either one of the following processing methods. <58> The hair dye B is preferably a hair dye containing one or more dyes selected from the group consisting of oxidation dyes, acid dyes, and basic dyes, and more preferably a hair dye containing an oxidation dye. <1> ~ <57> Either one of the following processing methods.

[0232] <59> The oxidation dye contains a coupler, and is preferably an oxidation dye intermediate (B) containing one or more selected from the group consisting of the following components (B1) and (B2): <58> How to process. (B1) One or more couplers selected from the group consisting of couplers (B1-1) having a benzene ring, electron-donating groups at the 1st and 3rd positions on the benzene ring, and hydrogen atoms at the 4th and 6th positions; couplers (B1-2) having a pyridine ring, electron-donating groups at the 2nd and 6th positions on the pyridine ring, and hydrogen atoms at the 3rd and 5th positions; and couplers (B1-3) represented by the following general formula (B13):

[0233] [ka]

[0234] (In formula (B13), R 11 is -O-(CH2) n R is a divalent group represented by -O- (n is a number of 2 or more and 10 or less). 12 , R 14 , R 22 and R24 is an electron-donating group, and R 15 and R 25 is a hydrogen atom. 13 , R 16 , R 23 and R 26 are each independently a hydrogen atom, an alkyl group, or an electron-donating group. (B2) One or more couplers other than the component (B1), selected from the group consisting of couplers (B2-1) having a benzene ring, electron-donating groups at the 1st and 2nd positions on the benzene ring, and hydrogen atoms at two or more of the 3rd to 6th positions, and couplers (B2-2) having a pyridine ring, electron-donating groups at the 2nd and 3rd positions on the pyridine ring, and hydrogen atoms at two or more of the 4th to 6th positions.

[0235] <60> The coupler (B1-1) preferably contains a compound represented by the following general formula (B11): <59> How to process.

[0236] [ka]

[0237] (In formula (B11), R 1 is an electron donating group attached to the carbon atom at position 1, R 2 is a hydrogen atom attached to the carbon atom at the 2nd position, an alkyl group or an electron-donating group, R 3 is an electron donating group attached to the 3-carbon atom, R 4 is a hydrogen atom, an alkyl group, or an electron-donating group bonded to the carbon atom at the 5-position. 2 and R 3 may be bonded to each other to form a hydrocarbon ring structure having aromaticity.

[0238] <61> The compound represented by the general formula (B11) includes one or more selected from the group consisting of meta-aminophenol, resorcinol, meta-phenylenediamine, 2-methylresorcinol, and 1-naphthol, and preferably includes one or more selected from the group consisting of meta-aminophenol, resorcinol, 2-methylresorcinol, and 1-naphthol. <60> How to process. <62> The coupler (B1-2) preferably contains a compound represented by the following general formula (B12): <59> ~ <61> Either one of the following processing methods.

[0239] [ka]

[0240] (In formula (B12), R 5 is an electron donating group attached to the 2nd carbon atom, R 6 represents a hydrogen atom, an alkyl group, or an electron-donating group bonded to the 4-carbon atom; R 7 is an electron-donating group attached to the 6-carbon atom.)

[0241] <63> The compound represented by the general formula (B12) contains 2,6-diaminopyridine. <62> How to process. <64> the coupler represented by general formula (B13) contains 1,3-bis(2,4-diaminophenoxy)propane; <59> ~ <63> Either one of the following processing methods. <65> The component (B1) preferably contains one or more selected from the group consisting of meta-aminophenol, resorcinol, meta-phenylenediamine, 2-methylresorcinol, 1-naphthol, 2,6-diaminopyridine, and 1,3-bis(2,4-diaminophenoxy)propane, and more preferably contains one or more selected from the group consisting of meta-aminophenol, resorcinol, 2-methylresorcinol, and 1-naphthol. <59> ~ <64> Either one of the following processing methods.

[0242] <66> The coupler (B2-1) preferably contains a compound represented by the following general formula (B21): <59> ~ <65> Either one of the following processing methods.

[0243] [ka]

[0244] (In formula (B21), R 31 is an electron donating group attached to the carbon atom at position 1, R 32 is an electron donating group attached to the 2nd carbon atom, R 33 ~R 36 are hydrogen atoms, alkyl groups, or electron-donating groups bonded to the 3-, 4-, 5-, and 6-position carbons, respectively. 33 ~R 36 At least two of these are hydrogen atoms.)

[0245] <67> The compound represented by the general formula (B21) contains one or more selected from the group consisting of ortho-aminophenol and 2,4-diaminophenoxyethanol. <66> How to process.

[0246] <68> The coupler (B2-2) preferably includes a compound represented by the following general formula (B22): <59> ~ <67> Either one of the following processing methods.

[0247] [ka]

[0248] (In formula (B22), R 37 is an electron donating group attached to the 2nd carbon atom, R 38 is an electron donating group attached to the 3-carbon atom. 39 ~R 41 are hydrogen atoms, alkyl groups, or electron-donating groups bonded to the 4-, 5-, and 6-position carbons, respectively. 39 ~R 41 At least two of these are hydrogen atoms.)

[0249] <69> The compound represented by the general formula (B22) includes 2,3-diaminopyridine, 2-amino-3-hydroxypyridine, and salts thereof. <68> How to process. <70> The component (B2) preferably contains a coupler (B2-1), more preferably one or more selected from the group consisting of ortho-aminophenol and 2,4-diaminophenoxyethanol. <59> ~ <69> Either one of the following processing methods.

[0250] <71> The oxidation dye intermediate (B) preferably contains a component (B1), and more preferably contains one or more selected from the group consisting of meta-aminophenol, resorcinol, meta-phenylenediamine, 2-methylresorcinol, 1-naphthol, 2,6-diaminopyridine, and 1,3-bis(2,4-diaminophenoxy)propane. <59> ~ <70> Either one of the following processing methods. <72> The oxidation dye intermediate (B) preferably contains a coupler (B1-1), more preferably contains one or more selected from the group consisting of meta-aminophenol, resorcinol, 2-methylresorcinol, and 1-naphthol. <59> ~ <70> Either one of the following processing methods. <73> The oxidation dye intermediate (B) further contains component (B3): precursor, <59> ~ <72> Either one of the following processing methods. <74> the component (B3) comprises one or more selected from the group consisting of paraphenylenediamine, toluene-2,5-diamine, orthochloroparaphenylenediamine, N-phenylparaphenylenediamine, N,N-bis(hydroxyethyl)paraphenylenediamine, 3-methyl-4-aminophenol, 2-hydroxyethylparaphenylenediamine, paraaminophenol, paramethylaminophenol, 4-amino-metacresol, and salts thereof, and preferably comprises one or more selected from the group consisting of toluene-2,5-diamine, paraaminophenol, 4-amino-metacresol, 1-hydroxyethyl-4,5-diaminopyrazole, and salts thereof; <73> How to process. <75> The molecular weight of the oxidation dye intermediate (B) is preferably 95 or more and 500 or less, more preferably 100 or more and 300 or less, and even more preferably 105 or more and 200 or less, as a non-dissociated type. <59> ~ <74> Either one of the following processing methods. <76> The acid dye preferably includes an acid dye (C) having a sulfonic acid group and satisfying at least one of the following (3) and (4): <58> ~ <75> Either one of the following processing methods. (3) Molecular weight of 500 or more (4) When the molecular weight is Mw, the difference (ab) between the number of sulfonic acid groups (a) and the number of cationic sites (b) divided by Mw [(ab) / Mw] is 0.0045 or less. <77> the number (a) of sulfonic acid groups in the acid dye (C) is preferably 1 or more and 6 or less, more preferably 1 or more and 5 or less, even more preferably 1 or more and 4 or less, still more preferably 1 or more and 3 or less, and still more preferably 2 or more and 3 or less; <76> How to process. <78> the cationic moiety comprises at least one selected from the group consisting of a quaternary ammonium cationic moiety and an iminium cationic moiety, and preferably comprises an iminium cationic moiety; <76> or <77> How to process. <79> the number (b) of cationic moieties in the acid dye (C) is preferably 0 or more and 5 or less, more preferably 0 or more and 4 or less, even more preferably 0 or more and 3 or less, still more preferably 0 or more and 2 or less, and still more preferably 1 or more and 2 or less; <76> ~ <78> Either one of the following processing methods. <80> the difference (ab) between the number (a) of sulfonic acid groups in the acid dye (C) and the number (b) of cationic sites in the acid dye (C) is preferably 1 or more and 5 or less, more preferably 1 or more and 4 or less, even more preferably 1 or more and 3 or less, and still more preferably 1 or more and 2 or less; <76> ~ <79> Either one of the following processing methods.

[0251] <81> When the acid dye (C) satisfies the above (3), the molecular weight of the acid dye (C) is preferably 500 or more and 1,500 or less, more preferably 500 or more and 1,200 or less, even more preferably 500 or more and 1,000 or less, still more preferably 500 or more and 900 or less, still more preferably 500 or more and 800 or less, still more preferably 500 or more and 780 or less, still more preferably 520 or more and 750 or less, and still more preferably 540 or more and 750 or less. <76> ~ <80> Either one of the following processing methods. <82> When the acid dye (C) satisfies the above (4), [(ab) / Mw] is preferably 0.0005 or more and 0.0045 or less, more preferably 0.0005 or more and 0.0040 or less, even more preferably 0.0010 or more and 0.0035 or less, and still more preferably 0.0010 or more and 0.0025 or less. <76> ~ <81> Either one of the following processing methods. <83> When the acid dye (C) satisfies the above (4), the molecular weight Mw is preferably 250 or more and 1,500 or less, more preferably 250 or more and 1,200 or less, even more preferably 250 or more and 1,000 or less, still more preferably 250 or more and 900 or less, still more preferably 280 or more and 800 or less, still more preferably 280 or more and 780 or less, still more preferably 280 or more and 750 or less, still more preferably 300 or more and 750 or less, and still more preferably 320 or more and 750 or less. <76> ~ <82> Either one of the following processing methods. <84> The acidic dye (C) is preferably Acid Black 52 (Color Index No. 15711), Acid Green 1 (Color Index No. 10020), Food Black 1 (Color Index No. 28440), Food Green 3 (Color Index No. 42053), Acid Green 5 (Color Index No. 42095), Acid Blue 9 (Color Index No. 42090), Acid Blue 5 (Color Index No. 42052), Acid Green 3 (Color Index No. 42085), Acid Green 25 (Color Index No. 61570), Acid Brown 13 (Color Index No. 10410), Acid Red 52 (Color Index No. 45100), Acid Black 1 (Color Index No. 20470), Acid Red 18 (Color Index No. 16255), Acid Red 27 (Color Index No. 16185), Acid Blue 3 (Color Index No. 42051), Acid Green 50 (Color Index No. 44090), Acid Red 73 (Color Index No. 27290), Acid Blue 1 (Color Index No. 42045), Acid Red 184 (Color Index No. 15685), Acid Red 35 (Color Index No. 18065), Acid Red 14 (Color Index No. 14720), Food Red 6 (Color Index No. 16155), Acid Orange 3 (Color Index No. 10385), Acid Orange 24 (Color Index No. 20170), Acid Violet 43 (Color Index No. 60730), Acid Blue 62 (Color Index No. 62045), Acid Red 88 (Color Index No. 15620), Acid Yellow 11 (Color Index No.18820)、Acid Yellow 36(Color Index No.13065)、Acid Yellow 1(Color Index No.10316)、Acid Orange 7(Color Index No.15510)、Acid Orange 20(Color Index No.14600)、Acid Orange 6(Color Index No.14270)、Food Red 17(Color Index No.16035)、Acid Red 41(Color Index No.16290)、Acid Red 1(Color Index No.18050)、Acid Red 155(Color Index No.18130)、Acid Red 180(Color Index No.18736)、Acid Yellow 17(Color Index No.18965)、Acid Yellow 23(Color Index No.19140)、Acid Red 163(Color Index No.24790)、Food Black 2(Color Index No.27755)、Direct Orange 39(Color Index No.40215)、Acid Blue 7(Color Index No.42080)、Acid Green 9(Color Index No.42100)、Acid Green 22(Color Index No.42170)、Acid Blue 104(Color Index No.42735)、Acid Violet 9(Color Index No.45190)、Acid Red 50(Color Index No.45220)、Acid Violet 50(Color Index No.50325)、Acid Black 2(Color Index No.50420)、Acid Blue 80(Color Index No.61585)、Acid Blue 87(Color Index No.74180)、Acid Red 195(Color Index No.18760)、Acid Red 249(Color Index No.and more preferably, one or more selected from the group consisting of Acid Black 52 (Color Index No. 15711), Acid Green 1 (Color Index No. 10020), Food Black 1 (Color Index No. 28440), Food Green 3 (Color Index No. 42053), Acid Green 5 (Color Index No. 42095), Acid Blue 9 (Color Index No. 42090), Acid Blue 5 (Color Index No. 42052), Acid Green 3 (Color Index No. 42085), Acid Green 25 (Color Index No. 61570), Acid Brown 13 (Color Index No. 10410), Acid Red 52 (Color Index No. 45100), Acid Black 1 (Color Index No. 17102). and Acid Red 18 (Color Index No. 16255), Acid Red 27 (Color Index No. 16185), Acid Blue 3 (Color Index No. 42051), Acid Green 50 (Color Index No. 44090), Acid Red 73 (Color Index No. 27290), Acid Blue 1 (Color Index No. 42045), Acid Blue 7 (Color Index No. 42080), Acid Green 9 (Color Index No. 42100), Acid Blue 104 (Color Index No. 42735), and Acid Violet 50 (Color Index No. 50325), more preferably Food Green 3 (Color Index No. 42053), Acid Green 5 (Color Index No. 42054), and the like, each of which has a cationic moiety (b) of 1 or more. No.42095), Acid Blue 9(Color Index No.42090), Acid Blue 5 (Color Index No. 42052), Acid Green 3 (Color Index No. 42085), Acid Red 52 (Color Index No. 45100), Acid Blue 3 (Color Index No. 42051), Acid Green 50 (Color Index No. 44090), and Acid Blue 1 (Color Index No. 42045), and even more preferably, at least one selected from the group consisting of Acid Blue 9 and Acid Red 52; <76> ~ <83> Either one of the following processing methods. <85> The basic dye preferably contains a basic dye (D) in which the value obtained by dividing the number of cationic moieties (a) by Mw [(a) / Mw] is 0.00275 or more, where Mw is the molecular weight. <58> ~ <84> Either one of the following processing methods. <86> the cationic moiety comprises at least one selected from the group consisting of a quaternary ammonium cationic moiety, an imidazolium cationic moiety, a pyridinium cationic moiety, a pyrrolidinium cationic moiety, a piperidinium cationic moiety, an iminium cationic moiety, and a pyrylium cationic moiety, and preferably comprises an imidazolium cationic moiety or a pyridinium cationic moiety; <85> How to process. <87> The molecular weight Mw of the basic dye (D) is preferably 200 or more and 500 or less, more preferably 220 or more and 450 or less, even more preferably 240 or more and 400 or less, still more preferably 250 or more and 360 or less, and still more preferably 250 or more and 340 or less. <85> or <86> How to process. <88> the number (a) of cationic moieties of the basic dye (D) is preferably 1 or more and 5 or less, more preferably 1 or more and 4 or less, even more preferably 1 or more and 3 or less, still more preferably 1 or more and 2 or less, and still more preferably 1; <85> ~ <87> Either one of the following processing methods. <89> When the molecular weight of the basic dye (D) is Mw, the value obtained by dividing the number of cationic moieties (a) by Mw [(a) / Mw] is preferably 0.00275 or more and 0.010 or less, more preferably 0.00275 or more and 0.008 or less, even more preferably 0.00275 or more and 0.006 or less, still more preferably 0.00275 or more and 0.005 or less, still more preferably 0.00280 or more and 0.005 or less, and still more preferably 0.00290 or more and 0.004 or less. <85> ~ <88> Either one of the following processing methods. <90> The basic dye (D) preferably comprises one or more selected from the group consisting of Basic Red 51, Basic Yellow 87, Basic Orange 31, Basic Blue 124, Basic Brown 16 (Color Index No. 12250), Basic Violet 14 (Color Index No. 42510), Basic Black 7 (Color Index No. 51215), Basic Blue 25 (Color Index No. 52025), Basic Blue 6 (Color Index No. 51175), Basic Red 2 (Color Index No. 50240), Basic Red 22 (Color Index No. 11055), Basic Blue 17 (Color Index No. 52040), and Basic Blue 9 (Color Index No. 52015), and more preferably comprises one or more selected from the group consisting of Basic Red 51, Basic Yellow 87, Basic Orange 31, Basic Blue 124, and Basic Brown 16, more preferably comprising one or more selected from the group consisting of Basic Red 51, Basic Yellow 87, Basic Orange 31, and Basic Blue 124, and even more preferably comprising one or more selected from the group consisting of Basic Red 51, Basic Yellow 87, and Basic Orange 31; <85> ~ <89> Either one of the following processing methods.

[0252] <91> The wet state in step (III) is a state after a step of increasing the moisture content of the hair and the fiber for a head accessory, and the water content in the fiber for a head accessory in the wet state is preferably a mass ratio (water / fiber for a head accessory) of 0.05 to 5, more preferably 0.10 to 5, even more preferably 0.2 to 5, still more preferably 0.3 to 5, more preferably 0.5 to 3, even more preferably 0.7 to 2, and still more preferably 1.0 to 2, when the mass of the fiber for a head accessory after conditioning at 20°C and a relative humidity of 65% for 24 hours is taken as 1. <1> ~ <90> Either one of the following processing methods. <92> In the step (III), the method of bringing the hair and the fiber for a head accessory into a wet state includes one or more of the following methods: (i) immersing the hair, to which the head accessory is attached, in a state where the hair and the fiber for a head accessory are in contact with each other, (ii) rinsing with water, (iii) washing with a hair cleanser composition, (iv) treating with a rinse-off conditioner or treatment and then rinsing with water, (v) applying a spray or mist containing water, (vi) applying steam, (vii) wrapping with a wet towel, or (vii) wrapping in plastic wrap, aluminum foil, or the like while wet with water. <1> ~ <91> Either one of the following processing methods. <93> The step (III) preferably includes one or more methods selected from the group consisting of (ii) a method of rinsing the hair on which the head accessory is attached with water, and (iii) a method of washing the hair with a hair wash composition, and more preferably includes a step of washing the hair and the head accessory fiber with a hair wash composition, followed by rinsing with water. <92> How to process. <94> In the step (III), the time for keeping the hair and the fiber for a head accessory in a wet state is preferably 1 second or more, more preferably 5 seconds or more, and is preferably 6 hours or less, more preferably 3 hours or less, and even more preferably 2 hours or less. <1> ~ <93> Either one of the following processing methods. <95> In the step (III), the temperature at which the hair and the fiber for a head accessory are kept wet is preferably higher than 0°C, more preferably 5°C or higher, and preferably 100°C or lower. <1> ~ <94> Either one of the following processing methods. <96> After carrying out the step (III), a step of drying the head accessory product and the hair to which it is attached is carried out. <1> ~ <95> Either one of the following processing methods. <97> A head accessory fiber treatment kit comprising a treatment composition A for treating head accessory fibers containing regenerated collagen fibers and a hair dye B for dyeing hair, The treatment composition A contains a compound (A) having a pKa value of 1 or more and 7 or less, and water, and has a pH of 2 or more and 6 or less, The regenerated collagen fiber is a fiber treatment kit for head accessories, which contains modified regenerated collagen fiber containing the following component (X): (X) A copolymer containing a structural unit derived from an unsaturated monomer having a carboxy group and a structural unit derived from an aromatic vinyl compound, the copolymer having an acid value of 100 mgKOH / g or more and a weight average molecular weight of 1500 or more and 15000 or less, or a salt thereof. <98> Use of composition A as a fiber treatment composition for headwear products containing regenerated collagen fibers, The composition A contains a compound (A) having a pKa value of 1 or more and 7 or less, and water, and has a pH of 2 or more and 6 or less, The regenerated collagen fibers contain the following component (X): (X) A copolymer containing a structural unit derived from an unsaturated monomer having a carboxy group and a structural unit derived from an aromatic vinyl compound, the copolymer having an acid value of 100 mgKOH / g or more and a weight average molecular weight of 1500 or more and 15000 or less, or a salt thereof. The modified regenerated collagen fiber contains The method for treating the fiber for head accessories with the composition A comprises the following steps (I) to (III): Use of composition A, comprising the following step (III) after the steps (I) and (II): Step (I) applying the composition A to the fiber for head accessories. Step (II) A step of attaching a head accessory containing the fiber for a head accessory to hair dyed with hair dye B. Step (III): A step of keeping the hair and the fiber for head accessories in a wet state while the hair and the fiber for head accessories are in contact with each other. <99> A treatment composition for treating fibers for headwear products containing regenerated collagen fibers, comprising: The composition contains a compound (A) having a pKa value of 1 or more and 7 or less, and water, and has a pH of 2 or more and 6 or less, The regenerated collagen fibers contain the following component (X): (X) A copolymer containing a structural unit derived from an unsaturated monomer having a carboxy group and a structural unit derived from an aromatic vinyl compound, the copolymer having an acid value of 100 mgKOH / g or more and a weight average molecular weight of 1500 or more and 15000 or less, or a salt thereof. The modified regenerated collagen fiber contains The method for treating fibers for head accessories with the composition includes the following steps (I) to (III): The treatment composition comprises the following step (III) after the steps (I) and (II): Step (I): Applying the treatment composition to the fiber for head accessories. Step (II) A step of attaching a head accessory containing the fiber for a head accessory to hair dyed with hair dye B. Step (III): A step of keeping the hair and the fiber for head accessories in a wet state while the hair and the fiber for head accessories are in contact with each other. <100> The compound (A) preferably contains a compound that satisfies at least one of the following (1) and (2), and more preferably contains one or more selected from the group consisting of a surfactant that satisfies the following (1) and a polymer that satisfies the following (2): <98> Use of, or <99> The treatment composition. (1) Al 3+ Chelate stability constant logK with ions is 2 or less (2) Molecular weight of 1500 or more <101> The compound (A) preferably has one or more acidic groups selected from the group consisting of a carboxy group and a sulfate group. <98> or <100> Use of, or <99> or <100> The treatment composition. <102> The compound (A) preferably contains one or more compounds selected from the group consisting of surfactants, polymers, and carboxylic acid compounds (excluding surfactants) having a molecular weight of less than 1500, each of which has one or more acidic groups selected from the group consisting of a carboxy group and a sulfate group; more preferably, it contains one or more compounds selected from the group consisting of surfactants satisfying the above (1), polymers satisfying the above (2), and carboxylic acid compounds (excluding surfactants) having a molecular weight of less than 1500, and even more preferably, it contains one or more compounds selected from the group consisting of alkyl sulfates, alkyl ether sulfates, alkyl ether carboxylates, N-acylamino acid salts, fatty acid amidopropyl betaine, anionic vinyl polymers containing structural units derived from (meth)acrylic acid, anionic polysaccharides, amphoteric polymers containing structural units derived from (meth)acrylic acid, amphoteric polymers containing a betaine group, and carboxylic acid compounds (excluding surfactants) having a molecular weight of less than 1500; and even more preferably, it contains one or more compounds selected from the group consisting of sodium lauryl sulfate, ammonium lauryl sulfate, polyoxyethylene lauryl ether sulfate, polyoxyethylene lauryl ether acetate, and N-lauroylmethylalanine. sodium, lauric acid amidopropyl betaine [lauramidopropyl betaine], palm kernel oil fatty acid amidopropyl betaine, coconut oil fatty acid amidopropyl betaine [cocamidopropyl betaine], polyacrylic acid, carboxymethylcellulose, xanthan gum, carrageenan, dimethyldiallylammonium chloride-acrylic acid copolymer (polyquaternium-22), acrylamide-acrylic acid-dimethyldiallylammonium chloride copolymer (polyquaternium-39), acrylic acid-methyl acrylate-methacrylamidopropyltrimethylammonium chloride copolymer (polyquaternium-47), acrylic acid-acrylamide-methacrylamidopropyltrimethylammonium chloride copolymer (polyquaternium-53), 2-pyrrolidone-5-carboxylic acid, and pyruvic acid, and more preferably sodium lauryl sulfate, ammonium lauryl sulfate, polyoxyethylene lauryl ether sodium sulfate, polyoxyethylene lauryl ether acetate, N-lauroylmethylalanine sodium, lauric acid amidopropyl betaine, polyacrylic acid,The composition contains at least one selected from the group consisting of xanthan gum, acrylamide-acrylic acid-dimethyldiallylammonium chloride copolymer (polyquaternium-39), 2-pyrrolidone-5-carboxylic acid, and pyruvic acid, and more preferably contains at least one selected from the group consisting of polyoxyethylene (3) lauryl ether sodium sulfate, polyoxyethylene (10) lauryl ether acetate, N-lauroylmethylalanine sodium, lauric acid amidopropyl betaine, polyacrylic acid (molecular weight 5000), polyacrylic acid (molecular weight 25000), xanthan gum, acrylamide-acrylic acid-dimethyldiallylammonium chloride copolymer (polyquaternium-39), 2-pyrrolidone-5-carboxylic acid, and pyruvic acid, <98> , <100> , <101> Use of any one of the following: <99> ~ <101> Any one of the treatment compositions.

[0253] <103> A method for treating fibers for headwear products containing regenerated collagen fibers, comprising: The regenerated collagen fiber includes a modified regenerated collagen fiber containing, as component (X), one or more selected from the following (X1) to (X3): The method comprises the following steps (I) to (III): A method for treating fibers for head accessories, comprising the following step (III) after the steps (I) and (II). Step (I) A step of applying to the fiber for headwear a treatment composition A containing water and one or more compounds (A) selected from the following (A1) to (A4) having a pKa value of 1 or more and 7 or less and satisfying at least one of the following (1) and (2), and having a pH of 2 or more and 5.5 or less, to the fiber for headwear: (1) Al 3+ Chelate stability constant logK with ions is 2 or less (2) Molecular weight of 1500 or more Step (II) A step of attaching a head accessory containing the fiber for a head accessory to hair dyed with hair dye B. Step (III): A step of keeping the hair and the fiber for head accessories in a wet state while the hair and the fiber for head accessories are in contact with each other. (X1) A styrene-maleic acid copolymer or a salt thereof having an acid value of 200 mgKOH / g or more and 600 mgKOH / g or less and a weight average molecular weight of 3,000 or more and 15,000 or less. (X2) A styrene-maleic acid copolymer or a salt thereof having an acid value of 200 mgKOH / g or more and 600 mgKOH / g or less and a weight average molecular weight of 6,000 or more and 15,000 or less. (X3) A styrene-maleic acid copolymer or a salt thereof having an acid value of 400 mgKOH / g or more and 600 mgKOH / g or less and a weight average molecular weight of 6,000 or more and 10,000 or less. (A1) One or more selected from sulfate ester-type anionic surfactants, carboxylic acid-type anionic surfactants, fatty acid amidopropyl betaine, (meth)acrylic acid homopolymers, polysaccharides having a carboxyl group, amphoteric polymers, and carboxylic acid compounds having a molecular weight of less than 1,500 (excluding surfactants). (A2) One or more selected from alkyl ether sulfates, alkyl ether carboxylates, N-acylamino acid salts, fatty acid amidopropyl betaine, polyacrylic acid having a weight-average molecular weight of 3,000 or more and 50,000 or less, polysaccharides having a carboxy group, amphoteric polymers, and carboxylic acid compounds having a molecular weight of less than 1,500 (excluding surfactants). (A3) One or more selected from polyoxyethylene lauryl ether sulfate, polyoxyethylene lauryl ether acetate, N-lauroylmethylalanine sodium, lauric acid amidopropyl betaine (lauramidopropyl betaine), polyacrylic acid having a weight-average molecular weight of 3,000 to 50,000, xanthan gum, acrylamide-acrylic acid-dimethyldiallylammonium chloride copolymer (polyquaternium-39), 2-pyrrolidone-5-carboxylic acid, and pyruvic acid (A4) One or more selected from polyoxyethylene lauryl ether sulfate, polyoxyethylene lauryl ether acetate, lauramidopropyl betaine (lauramidopropyl betaine), polyacrylic acid having a weight-average molecular weight of 3,000 to 50,000, acrylamide-acrylic acid-dimethyldiallylammonium chloride copolymer (polyquaternium-39), 2-pyrrolidone-5-carboxylic acid, and pyruvic acid

[0254] <104> A head accessory fiber treatment kit comprising a treatment composition A for treating head accessory fibers containing regenerated collagen fibers and a hair dye B for dyeing hair, The treatment composition A contains water and a compound (A) having a pKa value of 1 or more and 7 or less as a component (A) and satisfying at least one of the following conditions (1) and (2), the compound (A) including one or more compounds selected from the following (A1) to (A4), and has a pH of 2 or more and 5.5 or less: (1) Al 3+ Chelate stability constant logK with ions is 2 or less (2) Molecular weight of 1500 or more The regenerated collagen fiber is a fiber treatment kit for head accessories, which contains modified regenerated collagen fiber containing, as component (X), one component selected from the following (X1) to (X3): (A1) One or more selected from sulfate ester-type anionic surfactants, carboxylic acid-type anionic surfactants, fatty acid amidopropyl betaine, (meth)acrylic acid homopolymers, polysaccharides having a carboxyl group, amphoteric polymers, and carboxylic acid compounds having a molecular weight of less than 1,500 (excluding surfactants). (A2) One or more selected from alkyl ether sulfates, alkyl ether carboxylates, N-acylamino acid salts, fatty acid amidopropyl betaine, polyacrylic acid having a weight-average molecular weight of 3,000 or more and 50,000 or less, polysaccharides having a carboxy group, amphoteric polymers, and carboxylic acid compounds having a molecular weight of less than 1,500 (excluding surfactants). (A3) One or more selected from polyoxyethylene lauryl ether sulfate, polyoxyethylene lauryl ether acetate, N-lauroylmethylalanine sodium, lauric acid amidopropyl betaine (lauramidopropyl betaine), polyacrylic acid having a weight-average molecular weight of 3,000 to 50,000, xanthan gum, acrylamide-acrylic acid-dimethyldiallylammonium chloride copolymer (polyquaternium-39), 2-pyrrolidone-5-carboxylic acid, and pyruvic acid (A4) One or more selected from polyoxyethylene lauryl ether sulfate, polyoxyethylene lauryl ether acetate, lauramidopropyl betaine (lauramidopropyl betaine), polyacrylic acid having a weight-average molecular weight of 3,000 to 50,000, acrylamide-acrylic acid-dimethyldiallylammonium chloride copolymer (polyquaternium-39), 2-pyrrolidone-5-carboxylic acid, and pyruvic acid (X1) A styrene-maleic acid copolymer or a salt thereof having an acid value of 200 mgKOH / g or more and 600 mgKOH / g or less and a weight average molecular weight of 3,000 or more and 15,000 or less. (X2) A styrene-maleic acid copolymer or a salt thereof having an acid value of 200 mgKOH / g or more and 600 mgKOH / g or less and a weight average molecular weight of 6,000 or more and 15,000 or less. (X3) A styrene-maleic acid copolymer or a salt thereof having an acid value of 400 mgKOH / g or more and 600 mgKOH / g or less and a weight average molecular weight of 6,000 or more and 10,000 or less.

[0255] <105> The component (A) contains the component (A2). <103> or the processing method of <104> Kit. <106> The component (A) contains the component (A3). <103> or the processing method of <104> Kit. <107> The component (A) contains the component (A4). <103> or the processing method of <104> Kit. <108> The component (X) includes the component (X1). <103> , <105> ~ <107> Any one of the processing methods, or <104> ~ <107> One of the kits. <109> The component (X) contains the component (X2). <103> , <105> ~ <107> Any one of the processing methods, or <104> ~ <107> One of the kits. <110> The component (X) contains the component (X3). <103> , <105> ~ <107> Any one of the processing methods, or <104> ~ <107> One of the kits.

[0256] <111> The pH of the treatment composition A is 2 or more and 4.5 or less. <103> , <105> ~ <110> Any one of the processing methods, or <104> ~ <110> One of the kits. <112> The content of the component (A) in the treatment composition A is 0.1% by mass or more and 25% by mass or less. <103> , <105> ~ <111> Any one of the processing methods, or <104> ~ <111> One of the kits. <113> The content of the component (A) in the treatment composition A is 1.5% by mass or more and 15% by mass or less. <103> , <105> ~ <112> Any one of the processing methods, or <104> ~ <112> One of the kits. <114> The content of component (X) in the modified regenerated collagen fibers is 20% by mass or more and 40% by mass or less. <103> , <105> ~ <113> Any one of the processing methods, or <104> ~ <113> One of the kits. <115> The modified regenerated collagen fiber contains aluminum or a salt or complex thereof as component (Y). <103> , <105> ~ <114> Any one of the processing methods, or <104> ~ <114> One of the kits. <116> The content of component (Y) in the modified regenerated collagen fibers is 2.0% by mass or more and 10% by mass or less in terms of the amount of metal elements. <115> or the processing method of <115> Kit. <117> When applied by coating, the mass ratio [(X) / (A)] of the compound (A) in the treatment composition A to the component (X) in the regenerated collagen fibers is 2.0 or more and 7 or less. <103> , <105> ~ <116> Any one of the processing methods, or <103> , <105> ~ <116> One of the kits. <118> When applied by immersion, the mass ratio [(X) / (A)] of the compound (A) in the treatment composition A to the component (X) in the regenerated collagen fibers is 0.03 or more and 5 or less. <103> , <105> ~ <116> Any one of the processing methods, or <103> , <105> ~ <116> One of the kits. <119> When applied by immersion, the mass ratio [(X) / (A)] of the compound (A) in the treatment composition A to the component (X) in the regenerated collagen fibers is 0.10 or more and 0.5 or less. <103> , <105> ~ <116> Any one of the processing methods, or <103> , <105> ~ <116> and <118> One of the kits. <120> When applied by coating, the mass ratio [(Y) / (A)] of the compound (A) in the treatment composition A to the component (Y) in the regenerated collagen fibers is 0.10 or more and 0.2 or less. <115> ~ <117> Any one of the processing methods, or <115> ~ <117> One of the kits.

[0257] <121> When applied by immersion, the mass ratio [(Y) / (A)] of the compound (A) in the treatment composition A to the component (Y) in the regenerated collagen fibers is 0.005 or more and 1.0 or less. <115> , <116> and <118> ~ <119> Any one of the processing methods, or <115> ~ <116> and <118> ~ <119> One of the kits. <122> When applied by immersion, the mass ratio [(Y) / (A)] of the compound (A) in the treatment agent composition A to the component (Y) in the regenerated collagen fiber is 0.03 or more and 0.1 or less, the treatment method according to any one of <115> to <116>, <118> to <119>, and <121>, or the kit according to any one of <115> to <116>, <118> to <119>, and <121>. <123> The dyed wool material B contains at least one selected from the group consisting of oxidation dyes and basic dyes as dyes, the treatment method according to any one of <103>, <105> to <122>, or the kit according to any one of <104> to <122>. <124> The step (III) includes a step of washing the hair with the hair wearing the headgear product using a hair cleansing composition and then rinsing with water, the treatment method according to any one of <103>, <105> to <123>.

Examples

[0258] Hereinafter, the present invention will be described by examples, but the present invention is not limited to the scope of the examples. In these examples, various measurements and evaluations were performed by the following methods.

[0259] <pH measurement> The pH at 25 °C was measured using a pH meter (F-72, manufactured by Horiba, Ltd.).

[0260] <Weight average molecular weight of styrene-maleic acid copolymer> In this specification, the weight average molecular weight of the styrene-maleic acid copolymer was measured under the following conditions, and the weight average molecular weight in terms of polystyrene was determined. (1) Reagents · Ultrapure water: Milli-Q water produced by an ultrapure water production device, manufactured by Millipore · Dimethylformamide (DMF): Special grade, manufactured by Kanto Chemical Co., Inc. · Lithium bromide monohydrate (LiBr): Special grade, manufactured by Kanto Chemical Co., Inc. · Phosphoric acid: Special grade, manufactured by Sigma-Aldrich (2) Sample pretreatment method Approximately 50 mg of sample was precisely weighed, 0.5 mL of ultrapure water was added, and 10 mL of the mobile phase described below was added to dissolve the solution, which was then filtered to prepare a sample solution. (3) Measurement Using the sample solution and the standard solution, gel permeation chromatography (GPC) measurement was carried out under the following conditions to determine the weight average molecular weight in terms of polystyrene. ·Flow rate: 1mL / min Mobile phase: 60 mM phosphoric acid, 50 mM LiBr in DMF Column: TSKgel α (Alpha) column (Tosoh Corporation) Detector: RI (Differential Refractive Index Detector)

[0261] <Quantitative determination of styrene-maleic acid copolymer in modified regenerated collagen fibers> In this specification, the styrene-maleic acid copolymer in the modified regenerated collagen fibers was quantified by the following method. (1) Reagents 1 mol / L sodium hydroxide solution: for volumetric analysis, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Ultrapure water: Milli-Q ultrapure water production system, manufactured by Millipore Dimethylformamide (DMF): Special grade, manufactured by Kanto Chemical Co., Ltd. Lithium bromide monohydrate (LiBr): Special grade, manufactured by Kanto Chemical Co., Ltd. Phosphoric acid: Special grade, manufactured by Sigma-Aldrich (2) Sample solution The sample (modified regenerated collagen fiber) was conditioned at 20°C and 65% relative humidity for 24 hours, then finely chopped, and approximately 50 mg was precisely weighed. 10 mL of a 1 mol / L aqueous solution of sodium hydroxide was added, and the mixture was heated and dissolved at 50°C for 3 hours. The pH of the solution was adjusted to 4.7-5.3, and the freeze-dried sample was diluted with 0.5 mL of ultrapure water and 9.5 mL of the mobile phase described below. The diluted solution was then filtered to prepare the sample solution. (3) Preparation of calibration curve solution Separately, styrene-maleic acid copolymer was dissolved in the mobile phase described below to prepare a non-dissociated styrene-maleic acid copolymer with a concentration of 0.25 to 5.0 mg / mL, which was used as a standard solution for drawing a calibration curve. (4) Measurement Using the sample solution and the standard solution, gel permeation chromatography (GPC) measurements were performed under the following conditions to determine the peak areas of the sample solution and the standard solution. A calibration curve was also created based on the peak area of ​​the standard solution. ·Flow rate: 0.8mL / min Mobile phase: 60 mM phosphoric acid, 50 mM LiBr in DMF Column: TSKgel α (Alpha) column (Tosoh Corporation) Detector: UV-visible spectroscopic detector ·Measurement wavelength: 267nm (5) Calculation of the amount of styrene-maleic acid copolymer The amount of styrene-maleic acid copolymer per fiber mass was calculated using a calibration curve created based on the peak area derived from the styrene-maleic acid copolymer contained in the modified regenerated collagen fiber.

[0262] <Quantitative determination of aluminum in modified regenerated collagen fibers> In this specification, the quantitative determination of aluminum in the modified regenerated collagen fibers was carried out by the following method. (1) Reagents Sulfuric acid: for precision analysis, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Hydrochloric acid: for metal analysis, manufactured by Kanto Chemical Co., Ltd. Sodium carbonate: Special grade, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Boric acid: Special grade, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Aluminum standard solution: 1000 mg / L for atomic absorption analysis, manufactured by Kanto Chemical Co., Ltd. Ultrapure water: Milli-Q ultrapure water production system, manufactured by Millipore (2) Sample pretreatment method The modified regenerated collagen fiber bundle was hung in a dryer (SOFW-450SB, AS ONE Corporation) set to 60°C, a 250g weight was attached to the bottom end of the fiber bundle, and the fiber was dried for 1 hour under tension. The fiber was then removed from the dryer and conditioned at 20°C and 65% relative humidity for 24 hours. 0.1 g of sample (modified regenerated collagen fiber) was precisely weighed into a platinum crucible and heated until no more white smoke was emitted. After adding several drops of sulfuric acid, the mixture was heated again until no more white smoke was emitted and thoroughly incinerated in an electric furnace at 550°C. 1 g of an alkaline flux (sodium carbonate:boric acid = 1:0.4) was then added and the mixture was melted in an electric furnace at 950°C. A watch glass was placed over the sample, and 5 mL of ultrapure water and hydrochloric acid (6 mol / L) were added. The mixture was heated and dissolved on a hot plate at 70-80°C. After cooling, the solution was adjusted to a constant volume of 50 mL with ultrapure water and used as the measurement solution. (3) Preparation of calibration curve solution Using an aluminum standard solution (1000 mg / L), calibration curve solutions of 0.1 to 20 mg / L were prepared. An alkali flux and hydrochloric acid were added to each solution so that the concentrations were the same as those of the measurement solutions. (4) Measurement Using the prepared measurement solution, each element was measured under the following conditions using an ICP emission spectrometer. Analytical equipment: iCAP6500Duo (Thermo Fisher Scientific) ·Wavelength: Al 396.152nm RF power: 1150W Coolant gas flow rate: 12L / min Nebulizer flow rate: 0.70L / min Auxiliary gas: 0.5L / min Pump flow rate: 50 rpm

[0263] <Elastic modulus of fiber in water> (Underwater elastic modulus before treatment) (Step 1) Five fibers were cut from the fiber bundle, and a 3 cm fiber fragment was taken from each, for a total of five 3 cm fiber fragments. (Step 2) The fiber pieces were placed in an automatic fiber tensile tester (MTT690, manufactured by DIA-STRON Limited). After the fibers were immersed in water at 20°C for 30 minutes, automatic tensile measurement was started to determine the elastic modulus of the fibers when tensile in water. The cross-sectional area of ​​the fibers in water, which is necessary for determining the elastic modulus, was separately measured directly by optical microscopy.

[0264] (Underwater Elastic Modulus after Treatment in Step (I)) Using the fiber bundles treated in step (I) with the treatment composition A of each example (steps (II) and (III) were not carried out), fiber pieces were collected in the same manner as in the method described in "Elastic modulus in water before treatment," and the elastic modulus in water was measured.

[0265] <Improved underwater elastic modulus> The value of the underwater elastic modulus (MPa) after the treatment in step (I) minus the underwater elastic modulus (MPa) before the treatment is shown as the underwater elastic modulus improving effect in Table 5. The larger the value, the greater the effect of the treatment composition in improving the underwater elastic modulus.

[0266] <Mass reduction rate of fiber after treatment> The mass loss rate was calculated from the mass of the fiber bundle before and after treatment with treatment composition A of each example (steps (II) and (III) were not performed) using the following formula, and is shown in Table 5 and subsequent tables. The smaller the value, the less mass loss after treatment, i.e., the less fiber damage, and the better the results. The mass was measured after leaving the bundle to stand for at least 24 hours in an environment of 20°C and 65% RH. Mass reduction rate (%) = {(mass of fiber bundle before treatment) - (mass of fiber bundle after treatment)} / (mass of fiber bundle before treatment) × 100

[0267] <Shrinkage rate after contact with water vapor at 110°C (%)> The shrinkage rate after contact with water vapor at 110°C was measured by the following procedure. Evaluation was performed using fiber bundles before treatment and immediately after treatment with treatment composition A of each example (steps (II) and (III) were not performed). (Step 1) Fibers were cut from the fiber bundle, and a sample was prepared by fixing both ends of the five-fiber bundle with tape (Scotch tape, manufactured by 3M Co.) so that the length of the fibers between the tapes was 10.0 cm. (Step 2) The sample was placed in an autoclave (model number: LSX-700, manufactured by Tomy Kogyo Co., Ltd.) and heated at 110°C for 10 minutes. (Step 3) The sample was removed, and the length h (cm) of the fibers between the tapes was measured. The percentage of shrinkage compared to the length before heating was calculated, and this was taken as the shrinkage rate H (%) after contact with water vapor at 110°C. The closer H is to 0%, the less likely it is to shrink due to heat, indicating better heat resistance. Shrinkage rate after contact with water vapor at 110°C H (%) = [(10-h) / 10] x 100 (where h represents the length (cm) of the sample after heating at 110°C for 10 minutes.)

[0268] <Fiber heat shrinkage suppression effect (%)> Based on the shrinkage rate (%) after contact with water vapor at 110°C, the thermal shrinkage suppression effect (%) was calculated using the following formula and is shown in Table 5. The larger the value, the greater the effect of the treatment composition in improving heat resistance. Heat shrinkage suppression effect (%) = (shrinkage rate (%) after contact with water vapor at 110°C before treatment) - (shrinkage rate (%) after contact with water vapor at 110°C after treatment)

[0269] Manufacturing Example 1 (Manufacturing of Regenerated Collagen Fiber X0) Cowhide split hide was solubilized with alkali according to standard methods to prepare a spinning solution, which was then extruded from a spinning nozzle into a coagulation bath to produce regenerated collagen fibers. The regenerated collagen fibers were immersed in 30 parts by mass of an aqueous solution containing 5.0% by mass of aluminum sulfate 14-18 hydrate, 0.65% by mass of citric acid monohydrate, and 1.3% by mass of sodium hydroxide (component (Y))) at 30°C with circulation, with the dry mass being the fiber mass after conditioning at 20°C and 65% relative humidity for 24 hours. A 5% aqueous solution of sodium hydroxide was then added in portions over approximately 1 to 5 hours to adjust the final pH of the solution to 4.5 to 5.0 after 5 hours. The fibers were then left in the solution for another 3 hours and thoroughly washed with water to obtain regenerated collagen fiber X0.

[0270] Manufacturing Example 2 (Manufacturing of Modified Regenerated Collagen Fiber X1) The regenerated collagen fiber X0 obtained in Production Example 1 was treated according to the following procedure to obtain modified regenerated collagen fiber X1. (Step 1) Ten 30 cm long fiber bundles (amount that would have a mass of 1.5 g when dried at 60°C for 1 hour and then left at 20°C and 65% RH for 12 hours) were prepared from regenerated collagen fiber X0 for each example. First, using the agent X1a shown in Table 1, the following (Steps 2) to (Step 5) were carried out. Agents X1a and X1b shown in Table 1 were prepared by blending and mixing the components shown in Table 1 using styrene-maleic acid copolymer (XIRAN1000HNa, manufactured by Polyscope, weight average molecular weight (Mw): 9195, acid value: 475 mg KOH / g, styrene / maleic acid molar ratio: 1 / 1) as component (X). (Step 2) The fiber bundles prepared in (Procedure 1) were immersed in an amount of X1a agent such that the bath ratio (mass of fiber bundle after drying in Procedure 1: mass of X1a agent) was 1:30, using a separate container for each bundle, and the opening of each container was sealed. (Step 3) The container was immersed in a water bath (TBS221FA, Toyo Seisakusho Co., Ltd.) set at 40°C and left to stand for 5 minutes, and after the liquid temperature in the container was raised to 40°C, the container was removed from the water bath. (Step 4) The container containing the fiber bundle was placed on a stirring rotor (VMR-5R, AS ONE Corporation) installed in a dryer (SOFW-450SB, AS ONE Corporation) set at 40°C, and the container was rotated at a rotation speed of 80 rpm while being heated and stirred for 6 hours. (Step 5) The container containing the fiber bundle was removed from the dryer and returned to room temperature, after which the fiber bundle was taken out of the container, rinsed with running tap water at 30°C for 30 seconds, and the fiber flow was adjusted with a comb. (Step 6) The fiber bundle obtained in (Procedure 5) was subjected to (Procedure 2) to (Procedure 5) again, using the agent X1b shown in Table 1 instead of the agent X1a. However, the heating and stirring time in (Procedure 4) was set to 1 hour. (Step 7) The fiber bundles obtained in (Step 6) were hung one by one in a dryer set at 60°C, and a 250 g weight was attached to the bottom end of each fiber bundle, followed by drying for 1 hour with tension applied to the entire fiber. (Step 8) The fiber bundle was removed from the dryer, allowed to cool to room temperature, and the weight was removed.

[0271] [Table 1]

[0272] The blending amounts (mass %) shown in Table 1 are all amounts of active ingredients. The modified regenerated collagen fiber X1 produced in Production Example 2 above had a styrene-maleic acid copolymer content of 31.4 mass % and an aluminum content of 5.5 mass %.

[0273] Production Example 3 (Preparation of Hair Dye B1 Containing Oxidative Dye) The components shown in "Part 1" in Table 2 were blended and mixed until uniform to prepare Part 1. Similarly, the components shown in "Part 2" in Table 2 were blended and mixed until uniform to prepare Part 2. Before use, the first and second agents were mixed at a mass ratio of 1:1 to prepare hair dye B1 containing an oxidation dye, which was used for the evaluation described below.

[0274] Production Example 4 (Preparation of Hair Dye B2 Containing Basic Dye) The components shown in Table 3 were blended and mixed until uniform to prepare hair dye B2 containing a basic dye.

[0275] [Table 2]

[0276] [Table 3]

[0277] Examples 1 to 19 and Comparative Examples 1 to 21 (Fiber Treatment Method, Evaluation of Color Matching Effect) (Preparation of fiber bundle for evaluation) Fiber bundles for evaluation, each 10 cm long and weighing 1 g, were prepared using modified regenerated collagen fiber X1, regenerated collagen fiber X0, or white hair (Beaulux Co., Ltd.). The fiber bundles were washed with plain shampoo having the following composition, rinsed with warm water at 40°C, and thoroughly dried with a hair dryer before being used for evaluation.

[0278] (Plain shampoo composition) Ingredients (mass %) Polyoxyethylene (2) lauryl ether sodium sulfate (*1) 15.5 Lauric acid diethanolamide (*2) 1.5 edetic acid tetrasodium salt 0.3 Sodium benzoate 1.43 Refined water residue Total 100.0 *1: 57.4% by mass of Emar 227 (manufactured by Kao Corporation, active ingredient 27% by mass) *2: Aminone L-02 (Kao Corporation)

[0279] (Step (I): Treatment of fibers for headwear products and measurement of color) The components shown in "Treatment Composition A" in Table 5 below were blended and mixed until uniform to prepare the treatment composition A used in each example. The compound (A) used in treatment composition A is as shown in Table 4. Next, a fiber bundle for evaluation consisting of the fibers for head accessories shown in Table 5 and below, prepared by the above method, was immersed in treatment composition A in an amount such that the bath ratio (dry mass of fiber:mass of treatment composition A) was 1:30, where the mass of fiber after conditioning at 20°C and 65% relative humidity for 24 hours was taken as the dry mass, and the container was sealed. The container was then immersed in a water bath (TBS221FA, Toyo Seisakusho Co., Ltd.) set to 40°C and left to stand for the time shown in each table, thereby performing fiber treatment. After standing, the fiber bundle was removed from the container, rinsed with warm water at 40°C, and thoroughly dried in a dryer to obtain a treated fiber bundle.

[0280] The fiber bundle after the treatment in the above step (I) was subjected to the color (L0 * ,a0 * ,b0 * ) was measured using a color difference meter (CR-400, Konica Minolta, Inc.). * ,a0 * ,b0 * The values ​​were measured at six points per fiber bundle and the average value was calculated.

[0281] (Hair dyeing and color measurement) A hair bundle of 10 cm in length and 1 g in mass was prepared using white hair (Beaulux Co., Ltd.) equivalent to human hair. The hair bundle was washed with the plain shampoo having the above composition, rinsed with warm water at 40°C, and thoroughly dried with a hair dryer. The hair tresses were then dyed in the following manner. 2 g of hair dye B shown in Table 5 below was applied to the hair bundle. This was placed in a glass petri dish, the opening of which was covered with aluminum foil, and the hair bundle was left floating in a water bath (TBS221FA, Toyo Seisakusho Co., Ltd.) set to 30°C for 30 minutes. After leaving for 30 minutes, the fiber bundle was rinsed with 40°C warm water for 30 seconds to wash away hair dye B, and the procedure of lathering with plain shampoo of the above composition for 15 seconds and rinsing with 40°C warm water for 15 seconds was repeated twice. Next, plain conditioner of the following composition was applied for 15 seconds, followed by rinsing with 40°C warm water for 15 seconds, and then thoroughly dried with cold air from a hair dryer.

[0282] (Plain conditioner composition) Ingredients (mass %) Trimethylstearylammonium chloride (*1) 1.01 Distearyldimethylammonium chloride (*2) 2.0 Propylene glycol 5.0 Cetyl alcohol (*3) 2.0 Isopropyl alcohol 0.4 Methyl parahydroxybenzoate(*4) 0.1 Refined water residue Total 100.0 *1: 3.6% by mass of Kotamin 86W (manufactured by Kao Corporation, active ingredient 28% by mass) *2: 2.7% by mass of Kotamin D86P (manufactured by Kao Corporation, active ingredient 75% by mass) *3: Kalcol 6870 (Kao Corporation) *4: Mekkinsu M (manufactured by Ueno Pharmaceutical Co., Ltd.)

[0283] After dyeing, the color (L1 * ,a1 * ,b1 * ) was measured using a color difference meter (CR-400, Konica Minolta, Inc.). * ,a1 * ,b1 * Each measurement was taken at six points per hair bundle and the average value was calculated.

[0284] (Color difference between fiber for headwear products and human hair (immediately after dyeing hair: ΔE * Measurement of ab1) The color difference ΔE between the treated fiber bundle obtained in step (I) and the dyed hair bundle is calculated from the following formula: * ab1 was calculated and shown in Table 5 below. ΔE * The larger the value of ab1, the greater the color difference between the fiber bundle after the step (I) treatment and the hair bundle immediately after dyeing. ΔE * ab1=〔(L1 * -L0 * ) 2 +(a1 * -a0 * ) 2 +(b1 * -b0 * ) 2 〕 1 / 2

[0285] (Steps (II), (III)) The treated fiber bundle obtained in step (I) was overlapped with the dyed hair bundle, and the overlapped fiber bundle was immersed in a container containing 20 g of a solution prepared by diluting the plain shampoo 10 times with purified water. The container containing the fiber bundle was placed on a stirring rotor (VMR-5R, AS ONE Corporation) installed in a dryer (SOFW-450SB, AS ONE Corporation) set at 40°C, and the container was rotated at a rotation speed of 80 rpm and heated and stirred for 15 minutes. The container containing the fiber bundle was removed from the dryer and returned to room temperature, after which the fiber bundle was removed from the container, rinsed with running tap water at 40°C for 120 seconds, and thoroughly dried with cold air from a dryer.

[0286] (Color difference between fiber for headwear products and hair (after treatment in step (III): ΔE * Measurement of ab2) The fiber bundle after the step (III) treatment was measured for hue (L2 * ,a2 * ,b2 * The color (L3) of the hair bundle after the step (III) treatment was also measured using a color difference meter. * ,a3 *,b3 * ) was measured. According to the following formula, the color difference ΔE between the fiber bundle and the hair bundle after step (II) * ab2 was calculated and shown in Table 5 below. ΔE * ab2=〔(L3 * -L2 * ) 2 +(a3 * -a2 * ) 2 +(b3 * -b2 * ) 2 〕 1 / 2

[0287] (Color matching effect between hair accessories and fibers) ΔE * ab1-ΔE * The values ​​of ab2 were calculated and shown in Table 5. The larger this value, the greater the color matching effect due to dye transfer from the hair bundle corresponding to the hair to the fiber bundle corresponding to the fiber for the head accessory in step (III).

[0288] [Table 4]

[0289] [Table 5]

[0290] [Table 6]

[0291] [Table 7]

[0292] [Table 8]

[0293] Tables 5 to 8 show that when the method of the present invention is applied to specific modified regenerated collagen fibers (fibers for head accessories), the effect of improving the underwater elastic modulus is high, and the effect of improving the color compatibility between hair and the fiber for head accessories is also improved.

[0294] The effects of the present invention can also be achieved by using the modified regenerated collagen fibers shown in Formulation Example 1. Prescription example 1 Instead of XIRAN1000HNa (manufactured by Polyscope), XIRAN3000HNa (weight average molecular weight (Mw): 13803, acid value: 285 mg KOH / g, styrene / maleic acid molar ratio: 3 / 1, manufactured by Polyscope) was used, and the regenerated collagen fiber C0 obtained in Production Example 1 was treated in the same manner as in Production Example 2 to obtain modified regenerated collagen fiber B2. Next, the modified regenerated collagen fiber B2 is treated using the treatment composition shown in Table 5 below in the same procedure as in step (I) for treating fibers for head accessories. [Industrial Applicability]

[0295] According to the present invention, a method for treating fibers for head accessories can be provided that can improve the underwater elastic modulus of fibers for head accessories containing specific modified regenerated collagen fibers, reduce the color difference between hair and the fibers for head accessories, and improve the color matching effect.

Claims

1. A method for treating fibers for headwear products containing regenerated collagen fibers, comprising: The regenerated collagen fibers contain the following component (X): (X) A copolymer containing a structural unit derived from an unsaturated monomer having a carboxy group and a structural unit derived from an aromatic vinyl compound, the copolymer having an acid value of 100 mgKOH / g or more and a weight average molecular weight of 1,500 or more and 15,000 or less, or a salt thereof. The modified regenerated collagen fiber contains The method includes the following steps (I) to (III): A method for treating fibers for head accessories, comprising the following step (III) after the steps (I) and (II): Step (I): Applying a treatment composition A containing a compound (A) having a pKa value of 1 or more and 7 or less and water and having a pH of 2 or more and 6 or less to the fiber for head accessories. Step (II): A step of attaching a head accessory containing the fiber for a head accessory to hair dyed with hair dye B. Step (III): A step of keeping the hair and the fiber for a head accessory in a wet state while the hair and the fiber for a head accessory are in contact with each other.

2. The treatment method according to claim 1, wherein the compound (A) contains a compound that satisfies at least one of the following (1) and (2): (1) Al ３＋ Chelate stability constant log K with ions is 2 or less (2) Molecular weight of 1,500 or more

3. 3. The treatment method according to claim 1, wherein the compound (A) has one or more acidic groups selected from the group consisting of a carboxy group and a sulfate group.

4. The treatment method according to claim 2, wherein the compound (A) comprises one or more compounds selected from the group consisting of surfactants that satisfy the condition (1), polymers that satisfy the condition (2), and carboxylic acid compounds (excluding surfactants) that satisfy the condition (1) and have a molecular weight of less than 1,500.

5. 3. The treatment method according to claim 1 or 2, wherein the step (III) comprises a step of washing the hair on which the head accessory is attached with a hair wash composition, followed by rinsing with water.

6. The method according to claim 1 or 2, wherein the step (I) is performed before the step (II).

7. A head accessory fiber treatment kit comprising a treatment composition A for treating head accessory fibers containing regenerated collagen fibers and a hair dye B for dyeing hair, The treatment composition A contains a compound (A) having a pKa value of 1 or more and 7 or less, and water, and has a pH of 2 or more and 6 or less, The fiber treatment kit for head accessories includes modified regenerated collagen fibers containing the following component (X): (X) A copolymer containing a structural unit derived from an unsaturated monomer having a carboxy group and a structural unit derived from an aromatic vinyl compound, the copolymer having an acid value of 100 mgKOH / g or more and a weight average molecular weight of 1,500 or more and 15,000 or less, or a salt thereof.

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