Agent for treating regenerated collagen fibers

Abstract

To provide a regenerated collagen fiber-treating agent which can improve the underwater elastic modulus of a regenerated collagen fiber and can suppress the mass reduction of the fiber after the treatment.SOLUTION: The regenerated collagen fiber treatment agent composition contains a specific component (A) and water and has a pH of 2 or more and 6 or less, and the regenerated collagen fiber contains a modified regenerated collagen fiber containing a specific component (B).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a treatment agent for regenerated collagen fibers. [Background technology]

[0002] Regenerated collagen fiber, a protein fiber, is suitable for use as a raw material for artificial hair because its properties are similar to those of human hair.

[0003] 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. [Prior art documents] [Patent documents]

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

[0005] However, the inventors have found that when regenerated collagen fibers are treated with a modifier such as that disclosed in Patent Document 1, the elastic modulus in water tends to decrease, and that the fiber may be damaged by the fiber treatment, resulting in a decrease in mass of the fiber. Therefore, the present invention relates to a regenerated collagen fiber treatment composition that can improve the underwater elastic modulus of regenerated collagen fibers and suppress mass loss after treatment. [Means for solving the problem]

[0006] The present inventors have discovered that a treatment composition for regenerated collagen fibers, including specific modified regenerated collagen fibers, which contains components that meet specific requirements, can solve the above-mentioned problems. That is, the present invention relates to the following. [1] A regenerated collagen fiber treatment composition, The treatment composition contains the following component (A) and water, and has a pH of 2 or more and 6 or less, A regenerated collagen fiber treatment composition, wherein the regenerated collagen fiber comprises modified regenerated collagen fiber containing the following component (B): (A) A compound having a pKa value of 1 or more and 7 or less, a solubility of 1 g or more in 100 g of water at 25°C at pH 3, and containing 2 or less phenolic hydroxyl groups, and further satisfying at least one of the following conditions (1) and (2) (excluding component (B)): (1) Al 3+ Chelate stability constant logK with ions is 2 or less (2) Molecular weight of 1500 or more (B) 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. [2] A method for treating regenerated collagen fibers, comprising: The treatment method includes a step of applying a regenerated collagen fiber treatment composition to the regenerated collagen fibers, The treatment composition contains the following component (A) and water, and has a pH of 2 or more and 6 or less, A method for treating regenerated collagen fibers, wherein the regenerated collagen fibers include modified regenerated collagen fibers containing the following component (B): (A) A compound having a pKa value of 1 or more and 7 or less, a solubility of 1 g or more in 100 g of water at 25°C at pH 3, and containing 2 or less phenolic hydroxyl groups, and further satisfying at least one of the following conditions (1) and (2) (excluding component (B)): (1) Al 3+ Chelate stability constant logK with ions is 2 or less (2) Molecular weight of 1500 or more (B) 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. [3] Modified regenerated collagen fibers containing the following components (A) and (B): (A) A compound having a pKa value of 1 or more and 7 or less, a solubility of 1 g or more in 100 g of water at 25°C at pH 3, and containing 2 or less phenolic hydroxyl groups, and further satisfying at least one of the following conditions (1) and (2) (excluding component (B)): (1) Al 3+ Chelate stability constant logK with ions is 2 or less (2) Molecular weight of 1500 or more (B) 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. [4] A head accessory product comprising the modified regenerated collagen fiber described in [3]. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a regenerated collagen fiber treatment composition that can improve the underwater elastic modulus of specific modified regenerated collagen fibers and suppress mass loss after treatment. DETAILED DESCRIPTION OF THE INVENTION

[0008] [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.

[0009] [Regenerated collagen fiber treatment composition] The regenerated collagen fiber treatment composition of the present invention contains the following component (A) and water, has a pH of 2 or more and 6 or less, and the regenerated collagen fibers include modified regenerated collagen fibers containing the following component (B). (A) A compound having a pKa value of 1 or more and 7 or less, a solubility of 1 g or more in 100 g of water at 25°C at pH 3, and containing 2 or less phenolic hydroxyl groups, and further satisfying at least one of the following conditions (1) and (2) (excluding component (B)): (1) Al 3+ Chelate stability constant logK with ions is 2 or less (2) Molecular weight of 1500 or more (B) 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. In the following description, the regenerated collagen fiber treating composition may be simply referred to as the "treating composition (of the present invention)." The treating composition of the present invention has the above-mentioned structure, and therefore can improve the modulus of elasticity in water of the specific modified regenerated collagen fibers containing component (B), and can also suppress the loss of mass after treatment.

[0010] The reason why the treatment composition of the present invention exhibits the above-mentioned effects is not clear, but is presumed to be as follows. The modified regenerated collagen fibers that are the target of treatment with the treatment composition of the present invention have carboxy groups inside the fibers due to the inclusion of structural moieties derived from component (B). When the proportion of undissociated (acidic) carboxy groups is high, the hydrophobicity of the fibers is improved compared to when the proportion of dissociated (carboxy ion) carboxy groups is high, which is thought to result in an improved effect on the underwater elastic modulus.

[0011] Here, the treatment composition of the present invention has a pH of 2 or more and 6 or less, and component (A) contained in said treatment composition has a pKa value of 1 or more and 7 or less. In a treatment composition with a pH of 2 or more and 6 or less, component (A) having the above pKa value exhibits buffering ability, and therefore, by treating modified regenerated collagen fibers with said treatment composition, it is thought that the pH inside the fibers can be effectively lowered and the proportion of undissociated (acid type) carboxyl groups can be increased in the structural portion derived from component (B) inside the fibers. Component (A) has a solubility of 1 g or more in 100 g of water at 25°C at pH 3, making it possible to prepare a highly concentrated treatment composition with high buffering capacity, and effectively improving the modulus of elasticity in water of the modified regenerated collagen fibers after treatment. Furthermore, if the number of phenolic hydroxyl groups in component (A) is 2 or less, it is thought that discoloration of the modified regenerated collagen fibers due to oxidation after treatment can be suppressed. Furthermore, component (A) is a compound that satisfies at least one of the above (1) and (2) (excluding component (B)). Regarding requirement (1), Al 3+ If the chelate stability constant logK with ions is 2 or less, the ability to form chelates with the polyvalent metal ions contained in the regenerated collagen fibers is low, thereby suppressing the elution of polyvalent metal ions. This effect is thought to be able to suppress the loss of mass of the modified regenerated collagen fibers after treatment. Regarding requirement (2), if the molecular weight of component (A) is 1500 or more, excessive penetration of component (A) into the interior of the fiber can be prevented, and the elution of polyvalent metal ions due to chelation with the polyvalent metal ions in the fiber can be suppressed. This is thought to be able to suppress the loss of mass of the modified regenerated collagen fiber after treatment. The mechanism of action of the present invention is not limited to the above.

[0012] <Component (A)> Component (A) is a compound having a pKa value of 1 or more and 7 or less, a solubility of 1 g or more in 100 g of water at 25°C at pH 3, containing 2 or less phenolic hydroxyl groups, and satisfying at least one of the following conditions (1) and (2) (excluding component (B)): (1) Al 3+ Chelate stability constant logK with ions is 2 or less (2) Molecular weight of 1500 or more

[0013] (pKa) From the viewpoint of improving the modulus of elasticity in water of the modified regenerated collagen fibers, component (A) has a pKa value of 1 or more and 7 or less. Here, pKa is the acid dissociation index at 25°C, and when component (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).

[0014] From the viewpoint of improving the modulus of elasticity in water of the modified regenerated collagen fibers, the pKa of component (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 6, more preferably from 5 to 4. The pKa of component (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.

[0015] From the viewpoint of improving the elastic modulus in water of the modified regenerated collagen fibers, the pKa of component (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 the treatment composition of the present invention. The pKa of component (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 the treatment composition.

[0016] (Water solubility) Component (A) has a solubility of 1 g or more in 100 g of water at 25°C at pH 3. From the viewpoints of enabling the preparation of a highly concentrated treatment composition with high buffer capacity and further improving the modulus of elasticity in water after treatment, the solubility of component (A) in 100 g of water is preferably 2.5 g or more, more preferably 5 g or more, and even more preferably 10 g or more. 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 using hydrochloric acid or sodium hydroxide as a pH adjuster.

[0017] (Number of phenolic hydroxyl groups) The number of phenolic hydroxyl groups in component (A) is 2 or less, preferably 1 or less, and more preferably 0, from the viewpoint of suppressing discoloration of the modified regenerated collagen fibers due to oxidation after treatment.

[0018] (Requirements (1) and (2)) Component (A) is a compound that further satisfies at least one of the following conditions (1) and (2) (excluding component (B)): When component (A) satisfies at least one of the following conditions (1) and (2), it is believed that chelate formation between component (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

[0019] [Requirement (1)] If component (A) satisfies requirement (1), the Al content of component (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)). Component (A) Al 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.

[0020] [Requirement (2)] When component (A) satisfies requirement (2), the molecular weight of component (A) is 1,500 or more. The molecular weight of component (A) referred to here means the weight-average molecular weight of component (A) when component (A) is a polymer, and does not include the molecular weight of the counter ion that forms the salt when component (A) is a salt.

[0021] When component (A) satisfies requirement (2), the molecular weight of component (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 component (A) satisfies requirement (2), the molecular weight of component (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 component (A) is a polymer, the weight average molecular weight of component (A) refers to the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

[0022] From the viewpoint of improving the modulus of elasticity in water of the modified regenerated collagen fibers, component (A) preferably contains a compound having an acidic group, more preferably 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 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 a compound having a carboxy group, wherein 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.

[0023] The number of acidic groups in component (A) may be at least 1. When component (A) is a compound having a molecular weight of less than 1,500, the number of acidic groups in component (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.

[0024] 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, component (A) preferably contains one or more compounds 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.

[0025] [Surfactant] The surfactant used as component (A) preferably contains at least one surfactant selected from the group consisting of anionic surfactants and amphoteric surfactants that satisfy the above condition (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.

[0026] 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.

[0027] 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.

[0028] Among the preferred anionic surfactants used as component (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.

[0029] 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.

[0030] 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).

[0031] Among the above, the surfactant used as component (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, 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. more preferably, it 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, it contains one or more selected from the group consisting of sodium lauryl sulfate, ammonium lauryl sulfate, polyoxyethylene lauryl ether sodium sulfate, polyoxyethylene lauryl ether acetate, N-lauroylmethylalanine sodium, lauric acid amidopropyl betaine [lauramidopropyl betaine], palm kernel oil fatty acid amidopropyl betaine, and coconut oil fatty acid amidopropyl betaine [cocamidopropyl betaine].

[0032] 〔polymer〕 The polymer used as component (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 (B).

[0033] The anionic polymer used as component (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.

[0034] 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 viewpoint of improving the modulus of elasticity in water of the modified regenerated collagen fiber and improving the effect of suppressing mass loss after treatment.

[0035] 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.

[0036] Examples of anionic polysaccharides used as component (A) include polysaccharides having carboxy groups (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.

[0037] 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 component (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.

[0038] The amphoteric polymers used as component (A) include methacryloylethyl dimethyl betaine-methacryloylethyl trimethylammonium chloride-methoxy polyethylene glycol methacrylate copolymer (Polyquaternium-49), methacryloylethyl dimethyl betaine-methacryloylethyl trimethylammonium chloride-2-hydroxyethyl methacrylate copolymer (Polyquaternium-48), vinylpyrrolidone-N,N-dimethylaminoethyl methacrylate diethyl sulfate copolymer (Polyquaternium-11), and N,N-dimethylaminoethyl methacrylate diethyl 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.

[0039] 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).

[0040] Among the above, the polymer used as component (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, or the like. The polyacrylic acid may contain at least one selected from the group consisting of 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 more preferably 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.

[0041] [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.

[0042] One or more types of component (A) can be used. 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, component (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, ammonium lauryl sulfate, ammonium, sodium polyoxyethylene lauryl ether sulfate, polyoxyethylene lauryl ether acetate, sodium N-lauroylmethylalanine, 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.

[0043] <Component (A) 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 component (A) in the treatment composition 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, still more preferably 10% by mass or less, and still more preferably 5% by mass or less. The content of component (A) in the treatment composition 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. The content of component (A) in the treatment composition may also be 1.5% by mass or more and 5% by mass or less. When component (A) contains a polymer, the content of component (A) in the treatment composition 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 component (A) contains a polymer, the content of component (A) in the treatment composition 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.

[0044] <Water> The water used in the treatment composition of the present invention is not particularly limited, and for example, ion-exchanged water, pure water, distilled water, etc. can be used. The water content in the treatment composition is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 75% by mass or more, still more preferably 80% by mass or more, even more preferably 90% by mass or more, and preferably 99.99% by mass or less, even more preferably 97% by mass or less. The water content in the treatment composition may be the remainder of component (A). That is, the water content in the treatment composition is preferably 60% by mass or more and 99.99% by mass or less, more preferably 70% by mass or more and 97% by mass or less, even more preferably 75% by mass or more and 97% by mass or less, still more preferably 80% by mass or more and 97% by mass or less, and even more preferably 90% by mass or more and 97% by mass or less.

[0045] <Other ingredients> In addition to the above components, the treatment composition 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, the treatment composition contains, in addition to the above components, a cationic or nonionic surfactant, a cationic or nonionic polymer, and a higher alcohol.

[0046] (cationic surfactant) Examples of the cationic surfactant include (i) alkyltrimethylammonium salts, (ii) alkoxyalkyltrimethylammonium salts, (iii) dialkyldimethylammonium salts, (iv) alkylamidoalkyltrimethylammonium salts, (v) alkyldimethylamines and salts thereof, (vi) alkoxyalkyldimethylamines and salts thereof, and (vii) alkylamidoalkyldimethylamines and salts thereof.

[0047] (i) Examples of alkyltrimethylammonium salts include alkyltrimethylammonium salts having an alkyl group preferably having from 12 to 22 carbon atoms, more preferably from 16 to 20 carbon atoms. Specific examples include cetyltrimethylammonium chloride (cetrimonium chloride), stearyltrimethylammonium chloride (steartrimonium chloride), and behenyltrimethylammonium chloride.

[0048] (ii) Examples of alkoxyalkyltrimethylammonium salts include alkoxyalkyltrimethylammonium salts having an alkoxy group preferably having from 12 to 22 carbon atoms, more preferably from 16 to 20 carbon atoms. Specific examples include stearoxypropyltrimethylammonium chloride, stearoxyethyltrimethylammonium chloride, and stearoxyhydroxypropyltrimethylammonium chloride.

[0049] (iii) Examples of dialkyldimethylammonium salts include dialkyldimethylammonium salts having an alkyl group preferably having from 12 to 22 carbon atoms, more preferably from 16 to 20 carbon atoms. Specific examples include distearyl dimethylammonium chloride, dialkyl (C12-15) dimethylammonium salt, dicetyl (C16) dimethylammonium salt, dialkyl (C12-18) dimethylammonium salt, didecyl (C10) dimethylammonium salt, dilauryl (C12) dimethylammonium salt, dicocodimethylammonium salt (C8-16), dimyristyl (C14) dimethylammonium salt, distearyl (C18) dimethylammonium salt, dialachyl (C20) dimethylammonium salt, dibehenyl (C22) dimethylammonium salt, and stearyl lauryl dimethylammonium salt. Commercially available products include the "Cortamin" series manufactured by Kao Corporation, VARISOFT 432PPG (dicetyldimonium chloride) manufactured by EVONIK, rquad PC 2C-75 (dicocodimonium chloride) manufactured by AkzoNobel, and Lipocard 2C-75 (diacetyldimethylammonium chloride) manufactured by Lion Specialty Chemicals.

[0050] (iv) Examples of alkylamidoalkyltrimethylammonium salts include alkylamidoalkyltrimethylammonium salts having preferably an alkyl group having 11 to 21 carbon atoms, more preferably 13 to 19 carbon atoms, and specific examples thereof include palmitamidopropyltrimethylammonium chloride (palmitamidopropyltrimonium chloride).

[0051] (v) Alkyldimethylamine, (vi) alkoxyalkyldimethylamine, and (vii) alkylamidoalkyldimethylamine react with an acid to form a tertiary amine salt, which becomes a cationic surfactant.

[0052] The alkyl group in (v) alkyldimethylamines and salts thereof, and (vi) alkoxyalkyldimethylamines and salts thereof is preferably an alkyl group having from 12 to 22 carbon atoms, more preferably from 16 to 20 carbon atoms. The alkyl group in (vii) alkylamidoalkyldimethylamines and salts thereof is preferably an alkyl group having from 11 to 21 carbon atoms, more preferably from 15 to 19 carbon atoms.

[0053] (v) Examples of alkyldimethylamines and salts thereof include N,N-dimethylbehenylamine, N,N-dimethylstearylamine, and organic acid salts thereof, with N,N-dimethylbehenylamine lactate and N,N-dimethylstearylamine glycolate being preferred.

[0054] (vi) Examples of alkoxyalkyldimethylamines and salts thereof include N,N-dimethyl-3-hexadecyloxypropylamine, N,N-dimethyl-3-octadecyloxypropylamine, and organic acid salts thereof, and N,N-dimethyl-3-hexadecyloxypropylamine or a salt thereof, and N,N-dimethyl-3-octadecyloxypropylamine (stearoxypropyldimethylamine) or a salt thereof are preferred.

[0055] (vii) Examples of alkylamidoalkyldimethylamines and salts thereof include N-[3-(dimethylamino)propyl]docosanamide, N-[3-(dimethylamino)propyl]stearamide, and organic acid salts thereof, and preferred are the lactate salt of N-[3-(dimethylamino)propyl]docosanamide and the glycolate salt of N-[3-(dimethylamino)propyl]stearamide.

[0056] Other cationic surfactants include the quaternary ammonium salts described in JP-A-2019-34927.

[0057] (nonionic surfactant) Examples of nonionic surfactants include polyoxyalkylene alkyl ethers, polyoxyalkylene alkenyl ethers, sorbitan fatty acid esters, polyoxyalkylene sorbitan fatty acid esters, polyoxyalkylene fatty acid esters, alkyl glucosides, alkyl polyglycosides, alkyl glyceryl ethers, alkenyl glyceryl ethers, higher fatty acid sucrose esters, glycerin fatty acid esters, polyglycerin fatty acid esters, polyoxyethylene hydrogenated castor oil, alkyl saccharides, alkylamine oxides, alkylamidoamine oxides, fatty acid alkanolamides, polyoxyalkylene fatty acid alkanolamides, and (poly)ethylene glycol fatty acid esters.

[0058] Examples of sorbitan fatty acid esters include sorbitan monooleate (HLB: 5.7), sorbitan monostearate (HLB: 5.7), sorbitan monopalmitate (HLB: 6.6), sorbitan distearate (HLB: 3.9), sorbitan dipalmitate (HLB: 5.8), sorbitan tristearate (HLB: 2.1), and sorbitan tripalmitate (HLB: 5.0). Examples of polyoxyalkylene sorbitan fatty acid esters include polyoxyethylene sorbitan fatty acid esters.

[0059] The polyoxyalkylene alkyl ether preferably includes a polyoxyethylene alkyl ether or a polyoxypropylene alkyl ether having an alkyl group having from 8 to 22 carbon atoms, more preferably from 8 to 18 carbon atoms, and even more preferably from 8 to 12 carbon atoms, such as polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene isostearyl ether, polyoxypropylene butyl ether, and polypropylene glycol caprylyl ether. Specific examples of commercially available products include "Emulgen 103" (Laureth-3:PEG-3 Lauryl Ether), "Emulgen 116" (Laureth-16:PEG-16 Lauryl Ether), and "Kao Sofcare GP-1" (PPG-3 Caprylyl Ether), all manufactured by Kao Corporation.

[0060] The alkyl glucoside preferably includes alkyl glucosides having an alkyl group with 8 to 22 carbon atoms, more preferably 8 to 18 carbon atoms, and even more preferably 8 to 12 carbon atoms. Specific examples include "Mydol 10" (decyl glucoside) manufactured by Kao Corporation, and "Plantaren 2000 N UP" (decyl glucoside) and "Plantacare 818 UP" (coco glucoside) manufactured by BASF.

[0061] The alkyl glyceryl ether is preferably an alkyl glyceryl ether having an alkyl group having from 8 to 22 carbon atoms, more preferably from 8 to 18 carbon atoms, and even more preferably from 8 to 12 carbon atoms. Specific examples thereof include 2-ethylhexyl glyceryl ether, isostearyl glyceryl ether, and "Penetol GE-ID" (isodecyl glyceryl ether) manufactured by Kao Corporation.

[0062] (cationic polymer) Examples of cationic polymers include cationic polygalactomannans such as cationic guar gum, cationic tara gum, and cationic locust bean gum; cationic cellulose; cationic hydroxyalkyl celluloses such as cationic hydroxyethyl cellulose and cationic hydroxypropyl cellulose; cationic starch; cationic polyvinyl alcohol; and other quaternized dialkylaminoalkyl (meth)acrylate polymers; diallyl quaternary ammonium salt polymers such as polydiallyldimethylammonium chloride and diallyldimethylammonium chloride / acrylamide copolymer; and vinylimidazolium trichloride / vinylpyrrolidone copolymer. Polymers; vinylpyrrolidone / alkylaminoalkyl (meth)acrylate copolymer; vinylpyrrolidone / alkylaminoalkyl (meth)acrylate / vinylcaprolactam copolymer; vinylpyrrolidone / (meth)acrylamidopropyl trimethylammonium chloride copolymer; alkylacrylamide / (meth)acrylate / alkylaminoalkylacrylamide / polyethylene glycol (meth)acrylate copolymer; diallyldimethylammonium chloride-acrylamide copolymer (Polyquaternium-7); cationic polymers described in JP-A-53-139734 and JP-A-60-36407, etc.

[0063] Examples of commercially available cationic polymers include the following: (cationized guar gum) JAGUAR Excel, JAGUAR C-17, JAGUAR C-14-S (all manufactured by Solvay (Novecare)), etc. (cationized tara gum) Catinal CTR-100 (manufactured by Toho Chemical Industry Co., Ltd.), etc. (cationized locust bean gum) Catinal CLB-100 (manufactured by Toho Chemical Industry Co., Ltd.), etc. (cationized hydroxyethyl cellulose) Polyquaternium-10 (o-[2-hydroxy-3-(trimethylammonio)propyl]hydroxyethyl cellulose chloride): UCARE POLYMER JR-30M, UCARE POLYMER JR-400 (both manufactured by The Dow Chemical Company), Poise C-60H, Poise C-150L (both manufactured by Kao Corporation), etc. Polyquaternium-67: SoftCAT (Dow Chemical Company), etc. (cationized hydroxypropyl cellulose) SOFCARE C-HP2W (Kao Corporation), etc. (cationized polyvinyl alcohol) Gohsenex K-434 (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), CM318 (manufactured by Kuraray Co., Ltd.), etc. (Polydiallyldimethylammonium chloride) Polyquaternium-6: Marcote 100 (manufactured by Lubrizol), etc. (Diallyldimethylammonium chloride / acrylamide copolymer) Polyquaternium-7: Marcote 550 (manufactured by Lubrizol), etc.

[0064] (nonionic polymer) Examples of nonionic polymers include water-soluble polysaccharides such as starch, cellulose, guar gum, tara gum, locust bean gum, and glucomannan; hydroxyalkylated water-soluble polysaccharides such as hydroxyethyl cellulose and hydroxypropyl cellulose; polyalkylene glycols such as polyethylene glycol and polyethylene glycol-polypropylene glycol copolymer; and polyvinyl alcohol.

[0065] (higher alcohol) The higher alcohol is preferably an aliphatic primary alcohol having 12 to 22 carbon atoms, such as cetyl alcohol, oleyl alcohol, stearyl alcohol, isostearyl alcohol, 2-octyldodecanol, myristyl alcohol, behenyl alcohol, and cetostearyl alcohol, and one or more of these may be used.

[0066] <ph> The pH of the treatment composition 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 the treatment composition 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 the treatment composition is preferably 3.0 or more, more preferably 3.5 or more, even more preferably 4.0 or more, and 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 the treatment composition 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. 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.

[0067] <Dosage form, manufacturing method> The formulation of the treatment composition 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. The treatment composition of the present invention can also be used as any of 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 do not rinse 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 can be prepared in accordance with a conventional method.

[0068] <Modified regenerated collagen fiber> The regenerated collagen fibers to be treated with the treatment composition of the present invention include modified regenerated collagen fibers containing the following component (B). (B) 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.

[0069] (Component (B)) Component (B) is a modifier for regenerated collagen fibers. The regenerated collagen fibers to be modified by component (B) will be described later. Component (B) 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 (B), 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.

[0070] The structural unit derived from an aromatic vinyl compound in component (B) 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.

[0071] In component (B), the bonding state of the monomers that give each structural unit may be block bonding, random bonding, or a combination thereof.

[0072] Component (B) 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.

[0073] A suitable embodiment of component (B) 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 (B), from the viewpoint of further improving the modulus of elasticity in water when treated with the treatment composition of the present invention, 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.

[0074] In component (B), 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.

[0075] The acid value of component (B) is 100 mgKOH / g or more, and from the viewpoint of further improving the underwater elastic modulus when treated with the treatment composition of the present invention, 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 (B) 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, even more preferably 400 mgKOH / g or more and 600 mgKOH / g or less. Here, the acid value is the number of mg of potassium hydroxide required to neutralize 1 g of sample.

[0076] Specific examples of component (B) 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

[0077] Component (B) has a weight-average molecular weight of 1,500 or more and 15,000 or less. From the viewpoint of further improving the underwater elastic modulus when treated with the treatment composition of the present invention, the weight-average molecular weight 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. Component (B2) has a weight-average molecular weight of 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. Component (B) may also have a weight-average molecular weight of 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. The "weight average molecular weight" referred to here means 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.

[0078] (Content of component (B)) From the viewpoint of further improving the underwater elastic modulus when treated with the treatment composition of the present invention, the content of component (B) 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, even more preferably 3.0% by mass or more, still more preferably 5.0% by mass or more, even 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, even 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 (B) in the modified regenerated collagen fiber 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.

[0079] Furthermore, in this specification, the amount of component (B) in the modified regenerated collagen fibers is quantified by selecting an appropriate method that does not decompose component (B) 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 (B) is measured using, for example, GPC / UV, and the content of component (B) is calculated from the peak area. Specifically, the measurement can be performed using the method described in the Examples.

[0080] The mass ratio [(B) / (A)] of component (A) in the treatment composition of the present invention to component (B) in the regenerated collagen fibers may be controlled depending on the mode of use. For example, when the treatment composition is a coating type, the mass ratio of component (A) in the treatment composition to component (B) in the regenerated collagen fibers [(B) / (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 viewpoints of further improving the underwater elastic modulus after treatment, suppressing mass loss after treatment, and suppressing thermal shrinkage, 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 [(B) / (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. Furthermore, when the treatment composition is an immersion type, the mass ratio of component (A) in the treatment composition to component (B) in the regenerated collagen fibers [(B) / (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 viewpoints of further improving the underwater elastic modulus after treatment, suppressing mass loss after treatment, and suppressing thermal shrinkage, and can be set to preferably 150 or less, more preferably 100 or less, still 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 [(B) / (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.

[0081] (Component (C): Polyvalent metal, its salt, or its complex) In order to firmly coordinate component (B) inside the fiber and further improve the underwater elastic modulus when treated with the treatment composition of the present invention, the modified regenerated collagen fiber preferably further contains, in addition to component (B), a polyvalent metal, a salt thereof, or a complex thereof as component (C), which also acts as a modifier for the regenerated collagen fiber. Examples of component (C) 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 viewpoint of improving water resistance and further improving the modulus of elasticity in water when treated with the treatment composition of the present invention, component (C) 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.

[0082] When the modified regenerated collagen fibers contain component (C), the content of component (C) in the modified regenerated collagen fibers is, in terms of metal element content, preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1.0% by mass or more, even more preferably 2.0% by mass or more, and is preferably 40% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less, and even more preferably 10% by mass or less, from the viewpoint of improving water resistance and further improving the underwater elastic modulus when treated with the treatment composition of the present invention. The content of component (C) in the modified regenerated collagen fibers is, in terms of 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 even more preferably 2.0% by mass or more and 10% by mass or less. The amount of component (C) 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 metal elements are quantified using an ICP atomic emission spectrometer. The amounts of the metal elements can be measured specifically by the methods described in the Examples.

[0083] The mass ratio [(C) / (A)] of component (A) in the treatment composition of the present invention to component (C) in the regenerated collagen fibers may be controlled depending on the mode of use. For example, when the treatment composition is a coating type, the mass ratio of component (A) in the treatment composition to component (C) in the regenerated collagen fibers [(C) / (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, still more preferably 0.10 or more, from the viewpoints of further improving the underwater elastic modulus after treatment, suppressing mass loss after treatment, and suppressing thermal shrinkage, and can be set to 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 still more preferably 0.2 or less. That is, the mass ratio [(C) / (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 10 or less, still more preferably 0.02 or more and 5 or less, still more preferably 0.05 or more and 2 or less, still more preferably 0.05 or more and 1.0 or less, still more preferably 0.10 or more and 0.5 or less, and still more preferably 0.10 or more and 0.2 or less. Furthermore, when the treatment composition is used for immersion-type regenerated collagen fibers, the mass ratio of component (A) in the treatment composition to component (C) in the regenerated collagen fibers [(C) / (A)] can be set to 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, and 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, from the viewpoints of further improving the underwater elastic modulus after treatment, suppressing mass loss after treatment, and suppressing thermal shrinkage. That is, the mass ratio [(C) / (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, even 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.

[0084] (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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] [Treatment with a fiber treatment agent containing component (C)] Here, the modified regenerated collagen fiber used in the present invention preferably contains the above-mentioned component (C) 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 (C). The fiber treatment agent containing component (C) is preferably an aqueous solution containing a polyvalent metal salt or polyvalent metal complex corresponding to component (C). 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.

[0098] The content of the polyvalent metal salt and polyvalent metal complex in the fiber treatment agent is preferably 0.3% by mass or more and 5% by mass or less in terms of polyvalent metal oxide (aluminum oxide when the polyvalent metal is aluminum).

[0099] 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.

[0100] 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.

[0101] When treating with a fiber treatment agent containing component (C), 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) 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 fibers after conditioning at 20°C and a relative humidity of 65% for 24 hours is taken as the dry mass.

[0102] The temperature during treatment with the fiber treatment agent containing component (C) (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.

[0103] The treatment time (immersion time) with the fiber treatment agent containing component (C) 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.

[0104] 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.

[0105] [Treatment with a fiber treatment agent containing component (B)] Regenerated collagen fibers, or undried regenerated collagen fibers obtained by treatment with a fiber treatment agent containing component (C), are treated with a fiber treatment agent containing component (B) to obtain modified regenerated collagen fibers that are the target of treatment with the treatment composition of the present invention.

[0106] From the viewpoint of improving penetration into fibers and improving the treatment effect, the content of component (B) 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 (B) 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.

[0107] The fiber treating agent containing component (B) 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.

[0108] The fiber treating agent containing component (B) 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.

[0109] The pH of the fiber treatment agent containing component (B) 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 (B) 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.

[0110] Treatment with a fiber treatment agent containing component (B) can be carried out by immersing the regenerated collagen fibers, or undried regenerated collagen fibers obtained by treatment with a fiber treatment agent containing component (C), in the fiber treatment agent containing component (B).

[0111] When treating with a fiber treatment agent containing component (B), 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), when the mass of fibers after conditioning at 20°C and a relative humidity of 65% for 24 hours 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.

[0112] The temperature during treatment with a fiber treatment agent containing component (B) (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 (B) (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.

[0113] The treatment time (immersion time) with the fiber treatment agent containing component (B) 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 (B) 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.

[0114] Treatment with the fiber treatment agent containing component (B) 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.

[0115] 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.

[0116] The treatment with the fiber treatment agent containing component (B) 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 (C) in a fiber treatment agent containing component (B). (2) A step of removing the fibers immersed in the fiber treatment agent in (1) and rinsing them with water.

[0117] 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.

[0118] 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.

[0119] From the viewpoint of improving the treatment effect and productivity, the number of treatments with the fiber treatment agent containing component (B) 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.

[0120] By carrying out the above modification treatment, component (B) penetrates into the regenerated collagen fibers. Furthermore, when treatment is carried out with a fiber treatment agent containing component (C), component (B) is strongly coordinated to the polyvalent metal in the fibers. It is therefore believed that treating modified regenerated collagen fibers with the treatment agent composition of the present invention can improve the underwater elastic modulus.

[0121] The regenerated collagen fibers to be treated with the treatment composition of the present invention may be those containing 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 further improving the underwater elastic modulus after treatment, the regenerated collagen fibers to be treated with the treatment composition of the present invention are preferably fibers consisting solely of modified regenerated collagen fibers.

[0122] [Processing method] The present invention provides a method for treating regenerated collagen fibers, comprising: The treatment method includes a step of applying a regenerated collagen fiber treatment composition to the regenerated collagen fibers, The treatment composition contains the following component (A) and water, and has a pH of 2 or more and 6 or less, The present invention provides a method for treating regenerated collagen fibers, wherein the regenerated collagen fibers include modified regenerated collagen fibers containing the following component (B): (A) A compound having a pKa value of 1 or more and 7 or less, a solubility of 1 g or more in 100 g of water at 25°C at pH 3, and containing 2 or less phenolic hydroxyl groups, and further satisfying at least one of the following conditions (1) and (2) (excluding component (B)): (1) Al 3+ Chelate stability constant logK with ions is 2 or less (2) Molecular weight of 1500 or more (B) 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. In the following description, the method for treating regenerated collagen fibers will also be simply referred to as the "treatment method of the present invention."

[0123] The regenerated collagen fibers, the treatment composition, and preferred embodiments thereof are the same as those described for the regenerated collagen fiber treatment composition.

[0124] The treatment method of the present invention includes a step of applying the treatment composition to the regenerated collagen fibers. The method for applying the treatment composition to the regenerated collagen fibers may be any method that can bring the treatment composition into contact with the regenerated collagen fibers, and examples thereof include a method of applying the composition to dry or wet regenerated collagen fibers, and a method of immersing the regenerated collagen fibers in the composition. Of the above, the method of immersing dry regenerated collagen fibers in the treatment composition is preferred.

[0125] Here, when the content of component (A) in the treatment composition 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 component (A) applied per 1 g of dry mass 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 0.1 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 component (A) in the treatment composition 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 component (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 even 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.

[0126] From the viewpoint of balancing treatment effect and economic efficiency, the amount of treatment composition applied to the regenerated collagen fibers is preferably a bath ratio (dry mass of regenerated collagen fibers:mass of treatment composition) 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 the treatment composition, the bath ratio (dry mass of regenerated collagen fibers:mass of treatment composition) 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 the treatment composition is applied to regenerated collagen fibers, the bath ratio (dry mass of regenerated collagen fibers:mass of treatment composition) 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.

[0127] In addition, in this step, the treatment conditions for the regenerated collagen fibers may be set using the mass ratio [(B) / (A)] of component (A) in the treatment composition to component (B) in the regenerated collagen fibers as an index. Specifically, for example, when the treatment composition is applied to the regenerated collagen fibers, the mass ratio of component (A) in the treatment composition to component (B) in the regenerated collagen fibers [(B) / (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 viewpoints of further improving the underwater elastic modulus after treatment, suppressing mass loss after treatment, and suppressing thermal shrinkage, and this step may be performed under conditions such that the mass ratio 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 [(B) / (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, even 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 is immersed in the regenerated collagen fibers, this step may be performed under conditions such that the mass ratio [(B) / (A)] of component (A) in the treatment composition to component (B) in the regenerated collagen fibers 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 viewpoints of further improving the underwater elastic modulus after treatment, suppressing mass loss after treatment, and suppressing thermal shrinkage, 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 [(B) / (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.

[0128] Furthermore, the treatment conditions for the regenerated collagen fibers can also be set using the mass ratio [(C) / (A)] of component (A) in the treatment composition to component (C) in the regenerated collagen fibers as an index. Specifically, for example, when the treatment composition is applied to the regenerated collagen fibers, this step can be performed under conditions such that the mass ratio of component (A) in the treatment composition to component (C) in the regenerated collagen fibers [(C) / (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 viewpoints of further improving the underwater elastic modulus after treatment, suppressing mass loss after treatment, and suppressing thermal shrinkage, 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 [(C) / (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 10 or less, still more preferably 0.02 or more and 5 or less, still more preferably 0.05 or more and 2 or less, still more preferably 0.05 or more and 1.0 or less, still more preferably 0.10 or more and 0.5 or less, and still more preferably 0.10 or more and 0.2 or less. On the other hand, when the treatment composition is immersed in the regenerated collagen fibers, this step can be performed under conditions such that the mass ratio [(C) / (A)] of component (A) in the treatment composition to component (C) in the regenerated collagen fibers 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, 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, from the viewpoints of further improving the underwater elastic modulus after treatment, suppressing mass loss after treatment, and suppressing thermal shrinkage. That is, the mass ratio [(C) / (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.

[0129] When the treatment composition is applied to the 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.

[0130] After applying the treatment composition to the regenerated collagen fibers, it is preferable to further carry out a step of leaving the composition 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.

[0131] When regenerated collagen fibers are immersed in the treatment composition, 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.

[0132] The temperature at which the treatment composition 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.

[0133] The treatment method of the present invention may include a step of rinsing away excess treatment composition applied to the regenerated collagen fibers after applying the treatment composition to the regenerated collagen fibers and before carrying out 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 applied to the regenerated collagen fibers with water. The temperature of the water is not particularly limited, but warm water at 35 to 45°C is preferred.

[0134] The treatment 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 the treatment composition to the regenerated collagen fibers, or after the 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.

[0135] [Modified regenerated collagen fibers] The present invention further provides modified regenerated collagen fibers containing the following components (A) and (B): (A) A compound having a pKa value of 1 or more and 7 or less, a solubility of 1 g or more in 100 g of water at 25°C at pH 3, and containing 2 or less phenolic hydroxyl groups, and further satisfying at least one of the following conditions (1) and (2) (excluding component (B)): (1) Al 3+ Chelate stability constant logK with ions is 2 or less (2) Molecular weight of 1500 or more (B) 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.

[0136] The modified regenerated collagen fibers are regenerated collagen fibers modified with the above-mentioned components (A) and (B). From the viewpoint of further improving the modulus of elasticity in water after the treatment, the regenerated collagen fibers preferably further contain the above-mentioned component (C): a polyvalent metal, a salt thereof, or a complex thereof.

[0137] The modified regenerated collagen fibers of the present invention are preferably those in which the mass ratio [(B) / (A)] of component (A) in the treatment composition to component (B) in the regenerated collagen fibers is controlled according to the treatment method for the regenerated collagen fibers. That is, when regenerated collagen fibers are treated by application, the mass ratio of component (A) in the treatment composition to component (B) in the regenerated collagen fibers [(B) / (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 viewpoints of further improving the underwater elastic modulus after treatment, suppressing mass loss after treatment, and suppressing thermal shrinkage, 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 [(B) / (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, even 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 regenerated collagen fibers are treated by immersion, the mass ratio of component (A) in the treatment composition to component (B) in the regenerated collagen fibers [(B) / (A)] is, from the viewpoints of further improving the underwater elastic modulus after treatment, suppressing mass loss after treatment, and suppressing thermal shrinkage, 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, and is preferably 150 or less, more preferably 100 or less, still 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 [(B) / (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.

[0138] Furthermore, the modified regenerated collagen fibers of the present invention are preferably those in which the mass ratio [(C) / (A)] of component (A) in the treatment composition to component (C) in the regenerated collagen fibers is controlled according to the treatment method for the regenerated collagen fibers. That is, when regenerated collagen fibers are treated by application, the mass ratio of component (A) in the treatment composition to component (C) in the regenerated collagen fibers [(C) / (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, still more preferably 0.10 or more, from the viewpoints of further improving the underwater elastic modulus after treatment, suppressing mass loss after treatment, and suppressing thermal shrinkage, 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, still more preferably 0.2 or less. That is, the mass ratio [(C) / (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 10 or less, still more preferably 0.02 or more and 5 or less, still more preferably 0.05 or more and 2 or less, still more preferably 0.05 or more and 1.0 or less, still more preferably 0.10 or more and 0.5 or less, and still more preferably 0.10 or more and 0.2 or less. On the other hand, when the regenerated collagen fibers are treated by immersion, the mass ratio of component (A) in the treatment composition to component (C) in the regenerated collagen fibers [(C) / (A)] is, from the viewpoints of further improving the underwater elastic modulus after treatment, suppressing mass loss after treatment, and suppressing thermal shrinkage, 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, 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 [(C) / (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.

[0139] The modified regenerated collagen fibers can be obtained preferably by producing modified regenerated collagen fibers containing the component (B) by the above-mentioned method, and then treating the modified regenerated collagen fibers with a regenerated collagen fiber treatment composition containing the component (A). The method for treating the modified regenerated collagen fibers can preferably be the treatment method of the present invention.

[0140] [Fibers for headdress products, headdress products] The present invention further provides fibers for head accessories containing the modified regenerated collagen fibers, and head accessories containing the fibers. The modified regenerated collagen fibers can be suitably used as fibers for head accessories, either as they are or after further dyeing. In this specification, "head accessories" refers to, for example, hair wigs, hairpieces, weaving, hair extensions, braided hair, hair accessories, doll hair, etc. Furthermore, "fibers for head accessories" refers to fibers used in the above-mentioned head accessories. In this application, fibers for head accessories also include human hair. The head accessory product may be any product that contains at least a portion of modified regenerated collagen fibers, and may contain modified regenerated collagen fibers and human hair.

[0141] With respect to the above-mentioned embodiments, the present invention discloses the following. <1> A regenerated collagen fiber treatment composition, The treatment composition contains the following component (A) and water, and has a pH of 2 or more and 6 or less, A regenerated collagen fiber treatment composition, wherein the regenerated collagen fiber comprises modified regenerated collagen fiber containing the following component (B): (A) A compound having a pKa value of 1 or more and 7 or less, a solubility of 1 g or more in 100 g of water at 25°C at pH 3, and containing 2 or less phenolic hydroxyl groups, and further satisfying at least one of the following conditions (1) and (2) (excluding component (B)): (1) Al 3+ Chelate stability constant logK with ions is 2 or less (2) Molecular weight of 1500 or more (B) 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. <2> The pKa of the component (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> A regenerated collagen fiber treatment composition. <3> The pKa of the component (A) is preferably −3.0 or more and +3.0 or less, more preferably −2.0 or more and +2.0 or less, and more preferably −1.0 or more and +1.0 or less, relative to the pH value of the treatment composition. <1> or <2> A regenerated collagen fiber treatment composition. <4> The solubility of the component (A) in 100 g of water at 25°C at pH 3 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> ~ <3> Any one of the above regenerated collagen fiber treatment compositions. <5> The number of phenolic hydroxyl groups in the component (A) is preferably 1 or less, more preferably 0. <1> ~ <4> Any one of the above regenerated collagen fiber treatment compositions. <6> When the component (A) satisfies the above (1), Al of the component (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> ~ <5> Any one of the above regenerated collagen fiber treatment compositions. <7> When the component (A) satisfies the above (2), the molecular weight of the component (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> ~ <6> Any one of the above regenerated collagen fiber treatment compositions. <8> The component (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> ~ <7> Any one of the above regenerated collagen fiber treatment compositions. <9> When the component (A) is a compound having a molecular weight of less than 1,500, the number of acidic groups in the component (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> ~ <8> Any one of the above regenerated collagen fiber treatment compositions. <10> The component (A) preferably contains one or more 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. <8> or <9> A regenerated collagen fiber treatment composition.

[0142] <11> The surfactant used as the component (A) preferably satisfies the above (1) and contains at least one selected from the group consisting of anionic surfactants and amphoteric surfactants. <10> A regenerated collagen fiber treatment composition. <12> 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. <11> A regenerated collagen fiber treatment composition. <13> 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; <11> A regenerated collagen fiber treatment composition. <14> The surfactant used as the component (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 alkyl sulfates. the alkyl ether salt, alkyl ether sulfate, alkyl ether carboxylate, N-acylamino acid salt, and fatty acid amidopropyl betaine, and more preferably the alkyl ether salt comprises one or more selected from the group consisting of sodium lauryl sulfate, ammonium lauryl sulfate, sodium 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]; <10> ~ <13> Any one of the above regenerated collagen fiber treatment compositions. <15> The polymer used as the component (A) is a polymer other than the component (B), and preferably contains one or more polymers selected from the group consisting of anionic polymers and amphoteric polymers that satisfy the above (2). <10> ~ <14> Any one of the above regenerated collagen fiber treatment compositions. <16> 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. <15> A regenerated collagen fiber treatment composition. <17> 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. <16> A regenerated collagen fiber treatment composition. <18> The (meth)acrylic acid homopolymer contains one or more selected from the group consisting of polyacrylic acid and polymethacrylic acid. <17> A regenerated collagen fiber treatment composition. <19> 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; <17> A regenerated collagen fiber treatment composition. <20> The anionic polysaccharide used as the component (A) includes at least one selected from the group consisting of polysaccharides having a carboxy group and sulfates of polysaccharides. <16> ~ <19> Any one of the above regenerated collagen fiber treatment compositions.

[0143] <21> 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. <20> A regenerated collagen fiber treatment composition. <22> 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. <16> ~ <21> Any one of the above regenerated collagen fiber treatment compositions. <23> The anionic polymer used as the component (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. <15> ~ <22> Any one of the above regenerated collagen fiber treatment compositions. <24> The amphoteric polymer used as component (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 of 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), <15> ~ <23> Any one of the above regenerated collagen fiber treatment compositions. <25> The amphoteric polymer used as component (A) preferably contains one or more 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). <15> ~ <23> Any one of the above regenerated collagen fiber treatment compositions. <26> The polymer used as the component (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, and more preferably, the composition contains at least one selected from the group consisting of polyacrylic acid, xanthan gum, and acrylamide-acrylic acid-dimethyldiallylammonium chloride 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, the composition contains at least one selected from the group consisting of polyacrylic acid, xanthan gum, and acrylamide-acrylic acid-dimethyldiallylammonium chloride copolymer (Polyquaternium-39), <15> ~ <25> Any one of the above regenerated collagen fiber treatment compositions. <27> 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. <15> ~ <26> Any one of the above regenerated collagen fiber treatment compositions. <28> The component (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 carboxy groups and sulfate groups, 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 and 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 sodium 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, 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, <1> ~ <27> Any one of the above regenerated collagen fiber treatment compositions. <29> The content of component (A) in the treatment composition 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> ~ <28> Any one of the above regenerated collagen fiber treatment compositions. <30> When the component (A) contains a polymer, the content of the component (A) in the treatment composition 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. <29> A regenerated collagen fiber treatment composition.

[0144] <31> The water content in the treatment composition 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> ~ <30> Any one of the above regenerated collagen fiber treatment compositions. <32> The treatment composition contains, in addition to the above components, a cationic or nonionic surfactant, a cationic or nonionic polymer, and a higher alcohol. <1> ~ <31> Any one of the above regenerated collagen fiber treatment compositions. <33> The pH of the treatment composition 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> ~ <32> Any one of the above regenerated collagen fiber treatment compositions. <34> The treatment composition 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> ~ <33> Any one of the above regenerated collagen fiber treatment compositions. <35> the component (B) 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> ~ <34> Any one of the above regenerated collagen fiber treatment compositions. <36> In the component (B), 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> ~ <35> Any one of the above regenerated collagen fiber treatment compositions. <37> The acid value of the component (B) 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> ~ <36> Any one of the above regenerated collagen fiber treatment compositions. <38> The weight average molecular weight of the component (B) 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> ~ <37> Any one of the above regenerated collagen fiber treatment compositions. <39> The content of component (B) 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> ~ <38> Any one of the above regenerated collagen fiber treatment compositions. <40> The modified regenerated collagen fibers further contain a polyvalent metal, a salt thereof, or a complex thereof as component (C). <1> ~ <39> Any one of the above regenerated collagen fiber treatment compositions.

[0145] <41> The component (C) contains 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; <40> A regenerated collagen fiber treatment composition. <42> The content of component (C) 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. <40> or <41> A regenerated collagen fiber treatment composition. <43> A method for treating regenerated collagen fibers, comprising: The treatment method includes a step of applying a regenerated collagen fiber treatment composition to the regenerated collagen fibers, The treatment composition contains the following component (A) and water, and has a pH of 2 or more and 6 or less, A method for treating regenerated collagen fibers, wherein the regenerated collagen fibers include modified regenerated collagen fibers containing the following component (B): (A) A compound having a pKa value of 1 or more and 7 or less, a solubility of 1 g or more in 100 g of water at 25°C at pH 3, and containing 2 or less phenolic hydroxyl groups, and further satisfying at least one of the following conditions (1) and (2) (excluding component (B)): (1) Al 3+ Chelate stability constant logK with ions is 2 or less (2) Molecular weight of 1500 or more (B) 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. <44> The method for applying the treatment composition to regenerated collagen fibers includes a method of applying the composition to regenerated collagen fibers in a dry or wet state, or a method of immersing regenerated collagen fibers in the composition, and preferably includes a method of immersing regenerated collagen fibers in a dry state in the composition. <43> How to process. <45> When the content of component (A) in the treatment composition 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 component (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. <43> or <44> How to process. <46> The amount of the treatment composition 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 the regenerated collagen fibers:mass of the treatment composition) 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. <43> ~ <45> Either one of the following processing methods. <47> When the regenerated collagen fibers are immersed in the treatment composition, the bath ratio (dry mass of regenerated collagen fibers:mass of treatment composition) 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. <46> How to process. <48> When the treatment composition is applied to the regenerated collagen fibers, the bath ratio (dry mass of the regenerated collagen fibers:mass of the treatment composition) 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. <46> How to process. <49> When the treatment composition 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. <44> ~ <46> , <48> Either one of the following processing methods. <50> After applying the treatment composition to the regenerated collagen fibers, a step of leaving the composition to stand is further carried out, and 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. <44> ~ <46> , <48> ~ <49> Either one of the following processing methods.

[0146] <51> When the regenerated collagen fibers are immersed in the treatment composition, 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. <44> ~ <47> Either one of the following processing methods. <52> The temperature when the treatment composition 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 even more preferably 30°C or higher and 50°C or lower. <43> ~ <51> Either one of the following processing methods. <53> a step of rinsing away excess treatment composition applied to the regenerated collagen fibers after applying the treatment composition to the regenerated collagen fibers and before carrying out the next step; <43> ~ <52> Either one of the following processing methods. <54> a step of drying the regenerated collagen fibers after applying the treatment composition to the regenerated collagen fibers, and after performing a rinsing step, if any; <43> ~ <53> Either one of the following processing methods. <55> A modified regenerated collagen fiber containing the following components (A) and (B): (A) A compound having a pKa value of 1 or more and 7 or less, a solubility of 1 g or more in 100 g of water at 25°C at pH 3, and containing 2 or less phenolic hydroxyl groups, and further satisfying at least one of the following conditions (1) and (2) (excluding component (B)): (1) Al 3+ Chelate stability constant logK with ions is 2 or less (2) Molecular weight of 1500 or more (B) 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. <56> The modified regenerated collagen fiber further contains the component (C): a polyvalent metal, a salt thereof, or a complex thereof. <55> Modified regenerated collagen fiber. <57> <55> or <56> A fiber for headwear products comprising modified regenerated collagen fiber. <58> <55> or <56> A head accessory product comprising modified regenerated collagen fibers. <59> The headwear product is a hair wig, a hairpiece, a weaving, a hair extension, a braided hair, a hair accessory, or a doll hair. <57> Fibers for head accessories, or <58> Head ornament products.

[0147] <60> A regenerated collagen fiber treatment composition, The treatment composition contains the following component (A) and water, and has a pH of 2 or more and 5.5 or less, A regenerated collagen fiber treatment composition, wherein the regenerated collagen fiber comprises modified regenerated collagen fiber containing, as component (B), one component selected from the following (B1) to (B3): (A) A compound (excluding component (B)) that has a pKa value of 1 or more and 7 or less, a solubility of 1 g or more in 100 g of water at 25°C at pH 3, and has 2 or less phenolic hydroxyl groups, and further satisfies at least one of the following (1) and (2), and contains one or more compounds selected from the following (A1) to (A4): (1) Al 3+ Chelate stability constant logK with ions is 2 or less (2) Molecular weight of 1500 or more (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 acetate, polyacrylic acid having a weight-average molecular weight of 4,000 or more and 10,000 or less, and 2-pyrrolidone-5-carboxylic acid (B1) 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. (B2) 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. (B3) 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.

[0148] <61> A method for treating regenerated collagen fibers, comprising: The treatment method includes a step of applying a regenerated collagen fiber treatment composition to the regenerated collagen fibers, The treatment composition contains the following component (A) and water, and has a pH of 2 or more and 5.5 or less, A method for treating regenerated collagen fibers, wherein the regenerated collagen fibers include modified regenerated collagen fibers containing, as component (B), one component selected from the following (B1) to (B3): (A) A compound (excluding component (B)) that has a pKa value of 1 or more and 7 or less, a solubility of 1 g or more in 100 g of water at 25°C at pH 3, and has 2 or less phenolic hydroxyl groups, and further satisfies at least one of the following (1) and (2), and contains one or more compounds selected from the following (A1) to (A4): (1) Al 3+ Chelate stability constant logK with ions is 2 or less (2) molecular weight of 1500 or more; (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 sodium polyoxyethylene lauryl ether sulfate, polyoxyethylene lauryl ether acetate, sodium lauroylmethylalanine, 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 acetate, polyacrylic acid having a weight-average molecular weight of 4,000 or more and 10,000 or less, and 2-pyrrolidone-5-carboxylic acid (B1) 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. (B2) 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. (B3) 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.

[0149] <62> A modified regenerated collagen fiber containing the following component (A) and component (B): A colored modified regenerated collagen fiber obtained by modifying a modified regenerated collagen fiber containing component (B) using a treatment composition containing component (A). (A) A compound (excluding component (B)) that has a pKa value of 1 or more and 7 or less, a solubility of 1 g or more in 100 g of water at 25°C at pH 3, and has 2 or less phenolic hydroxyl groups, and further satisfies at least one of the following (1) and (2), and contains one or more compounds selected from the following (A1) to (A4): (1) Al 3+ Chelate stability constant logK with ions is 2 or less (2) molecular weight of 1500 or more; (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 sodium polyoxyethylene lauryl ether sulfate, polyoxyethylene lauryl ether acetate, sodium lauroylmethylalanine, 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 acetate, polyacrylic acid having a weight-average molecular weight of 4,000 or more and 10,000 or less, and 2-pyrrolidone-5-carboxylic acid (B1) 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. (B2) 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. (B3) 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.

[0150] <63> The component (A) contains the component (A3), <60> a regenerated collagen fiber treatment composition; <61> or <62> Modified regenerated collagen fiber. <64> The component (A) contains the component (A4), <60> a regenerated collagen fiber treatment composition; <61> or <62> Modified regenerated collagen fiber. <65> The component (B) contains the component (B2), <60> and <63> ~ <64> any one of the regenerated collagen fiber treatment compositions <61> and <63> ~ <64> Any one of the following processing methods, or <62> ~ <64> Regenerated collagen fibers that have been modified with any one of the following methods. <66> The component (B) contains the component (B3), <60> and <63> ~ <64> any one of the regenerated collagen fiber treatment compositions <61> and <63> ~ <64> Any one of the following processing methods, or <62> ~ <64> Regenerated collagen fibers that have been modified with any one of the following methods.

[0151] <67> The content of component (A) in the treatment composition is 0.2% by mass or more and 20% by mass or less. <60> and <63> ~ <66> any one of the regenerated collagen fiber treatment compositions <61> and <63> ~ <66> Any one of the following processing methods, or <62> ~ <66> Regenerated collagen fibers that have been modified with any one of the following methods. <68> The content of component (A) in the treatment composition is 1.5% by mass or more and 5% by mass or less. <60> and <63> ~ <67> any one of the regenerated collagen fiber treatment compositions <61> and <63> ~ <67> Any one of the following processing methods, or <62> ~ <67> Regenerated collagen fibers that have been modified with any one of the following methods. <69> The content of component (B) in the modified regenerated collagen fibers is 20% by mass or more and 40% by mass or less. <60> and <63> ~ <68> any one of the regenerated collagen fiber treatment compositions <61> and <63> ~ <68> Any one of the following processing methods, or <62> ~ <68> Regenerated collagen fibers that have been modified with any one of the following methods. <70> The modified regenerated collagen fibers contain aluminum or a salt or complex thereof as component (C). <60> and <63> ~ <69> any one of the regenerated collagen fiber treatment compositions <61> and <63> ~ <69> Either one of the following processing methods, or <62~ <69> Regenerated collagen fibers that have been modified with any one of the following methods. <71> The content of component (C) 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. <70> a regenerated collagen fiber treatment composition; <70> or <70> Modified regenerated collagen fiber.

[0152] <72> When the treatment composition is a coating type, the mass ratio [(B) / (A)] of the component (A) in the treatment composition to the component (B) in the modified regenerated collagen fibers is 2 or more and 7 or less. <60> and <63> ~ <71> any one of the regenerated collagen fiber treatment compositions <61> and <63> ~ <71> Any one of the following processing methods, or <62> ~ <71> Regenerated collagen fibers that have been modified with any one of the following methods. <73> When the treatment composition is a dip-type treatment composition, the mass ratio [(B) / (A)] of component (A) in the treatment composition to component (B) in the modified regenerated collagen fibers is 0.03 or more and 5 or less. <60> and <63> ~ <71> any one of the regenerated collagen fiber treatment compositions <61> and <63> ~ <71> Any one of the following processing methods, or <62> ~ <71> Regenerated collagen fibers that have been modified with any one of the following methods. <74> When the treatment composition is a dip-type treatment composition, the mass ratio of component (A) in the treatment composition to component (B) in the modified regenerated collagen fibers [(B) / (A)] is 0.10 or more and 0.5 or less. <60> , <63> ~ <71> and <73> any one of the regenerated collagen fiber treatment compositions <61> , <63> ~ <71> and <73> Any one of the following processing methods, or <62> ~ <71> and <73> Regenerated collagen fibers that have been modified with any one of the following methods. <75> When the treatment composition is a coating type, the mass ratio [(C) / (A)] of component (A) in the treatment composition to component (C) in the modified regenerated collagen fibers is 0.10 or more and 0.2 or less. <60> and <63> ~ <72> any one of the regenerated collagen fiber treatment compositions <61> and <63> ~ <72> Any one of the following processing methods, or <62> ~ <72> Regenerated collagen fibers that have been modified with any one of the following methods. <76> When the treatment composition is a dip-type treatment composition, the mass ratio [(C) / (A)] of component (A) in the treatment composition to component (C) in the modified regenerated collagen fibers is 0.005 or more and 1.0 or less. <60> , <63> ~ <71> and <73> ~ <74> any one of the regenerated collagen fiber treatment compositions <61> , <63> ~ <71> and <73> ~ <74> Any one of the following processing methods, or <62> ~ <71> and <73> ~ <74> Regenerated collagen fibers that have been modified with any one of the following methods. <77> When the treatment composition is a dip-type treatment composition, the mass ratio [(C) / (A)] of component (A) in the treatment composition to component (C) in the modified regenerated collagen fibers is 0.03 or more and 0.1 or less. <60> , <63> ~ <71> , <73> ~ <74> and <76> any one of the regenerated collagen fiber treatment compositions <61> , <63> ~ <71> , <73> ~ <74> and <76> Any one of the following processing methods, or <62> ~ <71> , <73> ~ <74> and <76> Regenerated collagen fibers that have been modified with any one of the following methods.

[0153] <78> The water content in the treatment composition is 90% by mass or more. <60> and <63> ~ <77> any one of the regenerated collagen fiber treatment compositions <61> and <63> ~ <77> Either one of the following processing methods. <79> The water content in the treatment composition is 90% by mass or more and 97% by mass or less. <60> and <63> ~ <78> any one of the regenerated collagen fiber treatment compositions <61> and <63> ~ <78> Either one of the following processing methods. <80> The pH of the treatment agent composition is 2 or more and 4.5 or less, and it is a regenerated collagen fiber treatment agent composition of any one of <60> and <63> to <79>, or a treatment method of any one of <61> and <63> to <79>.

Examples

[0154] Hereinafter, the present invention will be described by way of examples, but the present invention is not limited to the scope of the examples. In this example, various measurements and evaluations were performed by the following methods.

[0155] <pH measurement> Using a pH meter (F-72, manufactured by Horiba, Ltd.), the pH at 25 °C was measured.

[0156] <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 · Ultra-pure water: Milli-Q water produced by an ultra-pure water manufacturing apparatus, 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 the sample was precisely weighed, 0.5 mL of ultra-pure water was added, and 10 mL of the mobile phase described below was added and dissolved. The solution was filtered through a filter and used as the sample solution. (3) Measurement Using the sample solution and the standard solution, gel permeation chromatography (GPC) measurement was performed under the following conditions to determine the weight average molecular weight in terms of polystyrene. · Flow rate: 1 mL / min · Mobile phase; DMF containing 60 mM phosphoric acid and 50 mM LiBr · Column: TSKgel α (alpha) column (manufactured by Tosoh Corporation) · Detector; RI (differential refractive index detector)

[0157] <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.

[0158] <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

[0159] Manufacturing Example 1 (Manufacturing of regenerated collagen fiber C0) 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 (C))) at 30°C with circulation, with the dry mass being the fiber mass after conditioning for 24 hours at 20°C and 65% relative humidity. 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 fibers C0.

[0160] Production Example 2 (Production of Modified Regenerated Collagen Fiber B1) The regenerated collagen fiber C0 obtained in Production Example 1 was treated according to the following procedure to obtain modified regenerated collagen fiber B1. (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 C0 for each example. First, using the agent B1a shown in Table 1, the following steps (Procedure 2) to (Procedure 5) were carried out. Agents B1a and B1b 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 (B). (Step 2) The fiber bundles prepared in (Procedure 1) were immersed in an amount of B1a agent such that the bath ratio (mass of fiber bundle after drying in Procedure 1: mass of B1a 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 B1b shown in Table 1 instead of the agent B1a. 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.

[0161] [Table 1]

[0162] The blending amounts (mass %) shown in Table 1 are all amounts of active ingredients. The modified regenerated collagen fibers B1 produced in Production Example 2 above contained 31.4% by mass of styrene-maleic acid copolymer and 5.5% by mass of aluminum.

[0163] Examples 1 to 18, Comparative Examples 1 to 22 (Preparation of regenerated collagen fiber treatment composition) The components shown in Tables 2 and 3 were blended in the proportions shown in the tables and mixed until uniform. The pH was then adjusted to the values ​​shown in the tables using hydrochloric acid or sodium hydroxide to prepare regenerated collagen fiber treatment compositions.

[0164] (Preparation of fiber bundle for evaluation) A fiber bundle for evaluation, 10 cm long and 1 g in mass, was prepared using modified regenerated collagen fiber B1 or regenerated collagen fiber C0. The fiber bundle was 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.

[0165] (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)

[0166] (Textile processing) The treatment composition obtained in each example was used to treat modified regenerated collagen fiber B1 in Table 2 and regenerated collagen fiber C0, which does not correspond to modified regenerated collagen, in Table 3. Note that no fiber treatment was performed in Comparative Examples 3 and 22. The evaluation fiber bundle prepared by the above method was immersed in a treatment composition in an amount such that the bath ratio (dry fiber mass: treatment composition mass) was 1:30, where the dry fiber mass after 24 hours of conditioning at 20°C and 65% relative humidity was the fiber 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 indicated in each table, thereby performing fiber treatment. After standing, the fiber bundle was removed from the container, rinsed with 40°C warm water, and thoroughly dried in a dryer to obtain a treated fiber bundle.

[0167] The fiber bundles before and after treatment with the treatment composition were evaluated in the following manner. The results are shown in Tables 2 and 3.

[0168] <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 piece was set in an automatic fiber tensile tester (MTT690, manufactured by DIA-STRON Limited). After the fiber was immersed in water at 20°C for 30 minutes, automatic tensile measurement was started to determine the elastic modulus of the fiber when tensile in water. The cross-sectional area of ​​the fiber in water, which is necessary to determine the elastic modulus, was separately measured directly by observation with an optical microscope.

[0169] (Underwater elastic modulus after treatment) After treatment with the treatment composition of each example, fiber pieces were taken from the fiber bundles and the underwater elastic modulus was measured in the same manner as in the method described in "Underwater elastic modulus before treatment."

[0170] <Improved underwater elastic modulus> The underwater elastic modulus improvement effect, calculated by subtracting the underwater elastic modulus (MPa) after treatment from the underwater elastic modulus (MPa) before treatment, is shown in Tables 2 and 3. The larger the value, the greater the effect of the treatment composition in improving the underwater elastic modulus.

[0171] <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 the treatment composition using the following formula, and is shown in Tables 2 and 3. The smaller the value, the smaller the mass loss after treatment, i.e., the less fiber damage there was, and the better the results. The mass was measured after leaving the fiber bundle to stand for 24 hours or more 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

[0172] <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 carried out using a fiber bundle immediately after treatment with the treatment composition of each example. (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.)

[0173] [Table 2]

[0174] [Table 3]

[0175] The blending amounts (mass %) shown in Tables 2 and 3 are all amounts of active ingredients. As the components (A) and (A') shown in Tables 2 and 3, the components shown in Table 4 were used.

[0176] [Table 4]

[0177] Tables 2 and 3 show that the specific modified regenerated collagen fibers treated with the treatment composition of the present invention have a high effect of improving the elastic modulus in water and also have a small mass loss due to fiber treatment. Furthermore, except for Example 8, the fibers also have a lower shrinkage rate after contact with water vapor at 110°C compared to untreated modified regenerated collagen fibers (Comparative Example 3). Furthermore, when the hair bundles treated in the above examples were visually observed, no coloring was observed in any of them. In contrast, the modified regenerated collagen fibers of Comparative Examples 1 and 2, which were treated with an acidic compound that did not correspond to component (A), were able to improve the modulus of elasticity in water, but the mass loss rate after treatment increased significantly, despite the short treatment time. In Comparative Examples 4 to 21, in which regenerated collagen fibers other than the specific modified regenerated collagen fibers were treated with the treatment composition, the effect of improving the modulus of elasticity in water was not achieved.

[0178] 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 fibers B2 are treated with the treatment composition shown in Table 2 in the same manner as in (Fiber Treatment). [Industrial Applicability]

[0179] According to the present invention, it is possible to provide a regenerated collagen fiber treatment composition that can improve the underwater elastic modulus of specific modified regenerated collagen fibers and suppress mass loss after treatment.< / ph>

Claims

1. A regenerated collagen fiber treatment composition, The treatment composition contains the following component (A) and water, and has a pH of 2 or more and 6 or less, A regenerated collagen fiber treatment composition, wherein the regenerated collagen fiber comprises modified regenerated collagen fiber containing the following component (B): (A) A compound having a pKa value of 1 or more and 7 or less, a solubility of 1 g or more in 100 g of water at 25°C at pH 3, and containing 2 or less phenolic hydroxyl groups, and further satisfying at least one of the following conditions (1) and (2) (excluding component (B)): (1) Al ３＋ Chelate stability constant log K with ions is 2 or less (2) Molecular weight of 1,500 or more (B) 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.

2. 2. The regenerated collagen fiber treatment composition according to claim 1, wherein the component (A) comprises a compound having one or more acidic groups selected from the group consisting of a carboxy group and a sulfate group.

3. The regenerated collagen fiber treatment composition according to claim 1 or 2, wherein the component (A) comprises one or more selected from the group consisting of surfactants that satisfy (1), polymers that satisfy (2), and carboxylic acid compounds (excluding surfactants) that have a molecular weight of less than 1,500 and that satisfy (1).

4. 3. The regenerated collagen fiber treatment composition according to claim 1, wherein the content of said component (A) in said treatment composition is 0.01% by mass or more and 40% by mass or less.

5. 3. The regenerated collagen fiber treatment composition according to claim 1, wherein the component (B) comprises a styrene-maleic acid copolymer.

6. A method for treating regenerated collagen fibers, comprising: The treatment method includes a step of applying a regenerated collagen fiber treatment composition to the regenerated collagen fibers, The treatment composition contains the following component (A) and water, and has a pH of 2 or more and 6 or less, A method for treating regenerated collagen fibers, wherein the regenerated collagen fibers include modified regenerated collagen fibers containing the following component (B): (A) A compound having a pKa value of 1 or more and 7 or less, a solubility of 1 g or more in 100 g of water at 25°C at pH 3, and containing 2 or less phenolic hydroxyl groups, and further satisfying at least one of the following conditions (1) and (2) (excluding component (B)): (1) Al ３＋ Chelate stability constant log K with ions is 2 or less (2) Molecular weight of 1,500 or more (B) 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.

7. A modified regenerated collagen fiber containing the following components (A) and (B): (A) A compound having a pKa value of 1 or more and 7 or less, a solubility of 1 g or more in 100 g of water at 25°C at pH 3, and containing 2 or less phenolic hydroxyl groups, and further satisfying at least one of the following conditions (1) and (2) (excluding component (B)): (1) Al ３＋ Chelate stability constant log K with ions is 2 or less (2) Molecular weight of 1,500 or more (B) 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.

8. A head accessory product comprising the modified regenerated collagen fiber according to claim 7.

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