Dye composition for regenerated collagen fibers

Abstract

To provide a dyeing agent composition for a regenerated collagen fiber using a dye and excellent in fastness after dyeing the regenerated collagen fiber.SOLUTION: A staining agent composition for regenerated collagen fibers, wherein the staining agent composition contains a predetermined acid dye (A) and water, and the regenerated collagen fibers contain modified regenerated collagen fibers containing a specific component (B).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a dye composition for use on 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. Fibers used as raw materials for artificial hair are required to have high aesthetic qualities, such as color development and texture.

[0003] Protein fibers are generally colored by a dyeing method in which the protein fibers are immersed in an aqueous dye solution maintained at 70 to 100°C. For example, Patent Document 1 describes a dyeing method in which wool is immersed in an aqueous dye solution containing enzymes and the like to improve dye leveling, and then boiled at 100° C. for 60 minutes. Patent Document 2 describes a method for dyeing protein fibers such as wool, cashmere, and silk threads at a temperature of 70 to 90°C, which is lower than conventional dyeing temperatures, by using a specific treating agent. The example also discloses an example in which wool is treated with a specific treating agent and then dyed at a dyeing temperature of 85°C. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2-216282 [Patent Document 2] Japanese Patent Application Publication No. 7-126988 Summary of the Invention [Problem to be solved by the invention]

[0005] In conventional general dyeing methods for protein fibers, such as those disclosed in Patent Documents 1 and 2, even when special treatment agents are used, the dye cannot be sufficiently absorbed unless treatment is performed at a high temperature exceeding 70° C. Furthermore, when regenerated collagen fibers are dyed using a dyeing method that requires high-temperature conditions exceeding 70° C., there is a problem in that the regenerated collagen fibers shrink.

[0006] In order to solve the above problems, the inventors attempted to dye regenerated collagen fibers at temperatures below 70°C. However, when the dyeing temperature was low, the chemical reaction between the regenerated collagen fibers and the dye became insufficient, resulting in a problem of reduced dye fastness.

[0007] Therefore, the only practical method for coloring regenerated collagen fibers is to disperse a pigment such as carbon black in the solution spinning process of the regenerated collagen fibers. However, with coloring methods using pigments, the range of colors that can be colored is limited to achromatic colors such as black and gray, as well as chromatic colors such as red, yellow, blue, and purple, but it is difficult to produce vivid colors such as deep black.

[0008] Therefore, the present invention relates to a dye composition for regenerated collagen fibers that uses a dye and has excellent fastness after dyeing. [Means for solving the problem]

[0009] The present inventors have discovered that a dye composition for regenerated collagen fibers, including specific modified regenerated collagen fibers, which uses a specific acid dye, can solve the above-mentioned problems. That is, the present invention relates to the following. [1] A dye composition for regenerated collagen fibers, The dye composition contains the following component (A) and water, A dye composition for regenerated collagen fibers, wherein the regenerated collagen fibers comprise modified regenerated collagen fibers containing the following component (B): (A) An acid dye having a sulfonic acid group and satisfying at least one of the following conditions (1) and (2): (1) Molecular weight of 500 or more (2) When the molecular weight is Mw, the difference (ab) between the number of sulfonic acid groups (a) and the number of cationic sites (b) divided by Mw [(ab) / Mw] is 0.0045 or less. (B) One or more compounds selected from the group consisting of the following components (B1) and (B2): (B1) Benzoic acid or its salts (B2) 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 dyeing regenerated collagen fibers, comprising: The dyeing method includes a step of applying a dye composition for regenerated collagen fibers to the regenerated collagen fibers, The dye composition contains the following component (A) and water, A method for dyeing regenerated collagen fibers, wherein the regenerated collagen fibers include modified regenerated collagen fibers containing the following component (B): (A) An acid dye having a sulfonic acid group and satisfying at least one of the following conditions (1) and (2): (1) Molecular weight of 500 or more (2) When the molecular weight is Mw, the difference (ab) between the number of sulfonic acid groups (a) and the number of cationic sites (b) divided by Mw [(ab) / Mw] is 0.0045 or less. (B) One or more compounds selected from the group consisting of the following components (B1) and (B2): (B1) Benzoic acid or its salts (B2) 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] Colored modified regenerated collagen fiber containing the following components (A) and (B): (A) An acid dye having a sulfonic acid group and satisfying at least one of the following conditions (1) and (2): (1) Molecular weight of 500 or more (2) When the molecular weight is Mw, the difference (ab) between the number of sulfonic acid groups (a) and the number of cationic sites (b) divided by Mw [(ab) / Mw] is 0.0045 or less. (B) One or more compounds selected from the group consisting of the following components (B1) and (B2): (B1) Benzoic acid or its salts (B2) 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 comprising the colored head accessory fiber according to [3]. [Effects of the Invention]

[0010] According to the present invention, a dye composition for regenerated collagen fibers that uses a dye and has excellent fastness after dyeing can be provided. DETAILED DESCRIPTION OF THE INVENTION

[0011] [Definition] As used herein, "excellent dyeability of regenerated collagen fibers" means that there is a large change in color of regenerated collagen fibers before and after dyeing with a dye composition for regenerated collagen fibers. Furthermore, "fastness" means that there is little color change after the dyed regenerated collagen fibers are washed with water, a detergent, or the like. The dyeability and fastness can be specifically evaluated by the methods described in the examples.

[0012] [Dyeing composition for regenerated collagen fibers] The dye composition for regenerated collagen fibers of the present invention contains the following component (A) and water, and the regenerated collagen fibers include modified regenerated collagen fibers containing the following component (B). (A) An acid dye having a sulfonic acid group and satisfying at least one of the following conditions (1) and (2): (1) Molecular weight of 500 or more (2) When the molecular weight is Mw, the difference (ab) between the number of sulfonic acid groups (a) and the number of cationic sites (b) divided by Mw [(ab) / Mw] is 0.0045 or less. (B) One or more compounds selected from the group consisting of the following components (B1) and (B2): (B1) Benzoic acid or its salts (B2) 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 dye composition for regenerated collagen fibers may be simply referred to as the "composition (of the present invention)." Since the composition of the present invention has the above-mentioned structure, even if it is a dye composition using a dye, the dyed modified regenerated collagen fibers have excellent fastness after dyeing. The molecular weight of component (A) here refers to the molecular weight in the undissociated (acid) state. For example, even if at least a portion of the sulfonic acid groups in component (A) are in the form of sulfonate salts, the molecular weight of component (A) refers to the molecular weight in the undissociated sulfonic acid state, and does not include the molecular weight of the counter ion. Note that this also includes cases where component (A) has an onium group such as a quaternary ammonium group, and in such cases, the counter ion is similarly not included in the molecular weight.

[0013] The reason why the composition of the present invention exhibits the above-mentioned effects is not clear, but is presumed to be as follows. The regenerated collagen fibers to be dyed with the composition of the present invention include modified regenerated collagen fibers (hereinafter simply referred to as "modified regenerated collagen fibers") containing one or more compounds (B) selected from the group consisting of the above-mentioned components (B1) and (B2). Component (B) acts as a modifier for the regenerated collagen fibers. The composition of the present invention contains, as the acid dye, (A) an acid dye having a sulfonic acid group and satisfying at least one of the above (1) and (2) (hereinafter simply referred to as "component (A)" or "acid dye (A)"). Inside the modified regenerated collagen fibers, the structural portion derived from component (B) interacts with the sulfonic acid group in the acid dye (A), which is thought to facilitate retention of the acid dye inside the fibers, thereby further improving fastness. On the other hand, acid dyes with low molecular weights are usually more suitable for use in dyeing hair, as they penetrate into the interior of the hair and improve dyeability and fastness. In contrast, regenerated collagen fibers, which are the subject of dyeing with the composition of the present invention, differ from hair in that they do not have a barrier structure such as a cuticle that separates the inside and outside of the fiber. Therefore, if low-molecular-weight acid dyes are used, the color may easily fade after dyeing, and fastness may be reduced.

[0014] In contrast, when the acid dye used in the composition of the present invention contains an acid dye that satisfies the above (1), it is thought that the large molecular weight makes it difficult for the color to fade after dyeing, and that this improves fastness. Furthermore, since the object to be dyed is regenerated collagen fiber, it is thought that, unlike hair, it is possible to dye the fiber by penetrating the acid dye into the fiber.

[0015] When the acid dye used in the composition of the present invention contains an acid dye that satisfies the above condition (2), the following can be considered. The modified regenerated collagen fibers, which are the target of dyeing with the composition of the present invention, contain structural moieties derived from component (B) within the fibers. Because these structural moieties contain aromatic rings, they have a high affinity with acid dyes that also contain aromatic rings due to aromatic ring interactions, which is thought to improve the fixability of the acid dye. At the same time, however, these structural moieties are anionic. Therefore, when an acid dye containing only anionic moieties, such as sulfonic acid groups or sulfonate ions, is used, charge repulsion occurs between the structural moieties derived from component (B) in the modified regenerated collagen fibers and the acid dye, which can have a detrimental effect on the fixability of the acid dye to the fibers. However, when the acid dye contains cationic moieties or has a small number of sulfonic acid groups relative to its molecular weight, this charge repulsion is reduced. Therefore, the contribution of aromatic ring interactions to the fixability of the acid dye to the modified regenerated collagen fibers is thought to outweigh charge repulsion, resulting in improved fixability and further improved dyeability and fastness. In other words, when the molecular weight of the acid dye is Mw, and the difference (ab) between the number of sulfonic acid groups (a) and the number of cationic sites (b) in the acid dye is divided by Mw ((ab) / Mw), this is a predetermined value or less, and the charge repulsion between the structural portion derived from component (B) in the modified regenerated collagen fiber and the acid dye can be sufficiently reduced, thereby improving the fixation of the acid dye to the modified regenerated collagen fiber and further improving the dyeability and fastness. The mechanism of action of the present invention is not limited to the above.

[0016] <Component (A): Acid dye> Component (A) is an acid dye that has a sulfonic acid group and satisfies at least one of the following (1) and (2) from the viewpoint of improving the fastness of the modified regenerated collagen fiber after dyeing. (1) Molecular weight of 500 or more (2) When the molecular weight is Mw, the difference (ab) between the number of sulfonic acid groups (a) and the number of cationic sites (b) divided by Mw [(ab) / Mw] is 0.0045 or less. Component (A) may be an acid dye that satisfies either one of the above (1) and (2), or may be an acid dye that satisfies both the above (1) and (2).

[0017] The number (a) of sulfonic acid groups in component (A) may be 1 or more, and from the viewpoint of improving the dyeability and fastness of the modified regenerated collagen fiber, it is preferably 1 or more, more preferably 2 or more, and preferably 6 or less, more preferably 5 or less, even more preferably 4 or less, and still more preferably 3 or less. That is, the number (a) of sulfonic acid groups in component (A) is preferably 1 or more and 6 or less, more preferably 1 or more and 5 or less, even more preferably 1 or more and 4 or less, still more preferably 1 or more and 3 or less, and still more preferably 2 or more and 3 or less. Here, "the number (a) of sulfonic acid groups in component (A)" means the number of sulfonic acid groups in component (A) in the undissociated (acid) state.

[0018] Component (A) may be at least partially in the form of a salt, and from the viewpoint of improving the dyeability and fastness of the modified regenerated collagen fiber, the salt preferably includes an ammonium salt or a metal salt, more preferably an ammonium salt or one or more metal salts selected from the group consisting of alkali metals, alkaline earth metals, and transition metals, more preferably an ammonium salt or one or more metal salts selected from the group consisting of potassium, sodium, calcium, iron, and chromium, even more preferably an ammonium salt or one or more metal salts selected from the group consisting of sodium, calcium, iron, and chromium, and even more preferably a sodium salt.

[0019] From the viewpoint of improving the robustness of the modified regenerated collagen fibers, it is preferable that component (A) further have a cationic moiety. Examples of the cationic moiety include quaternary ammonium cationic moieties and iminium cationic moieties, and from the viewpoint of improving the robustness of the modified regenerated collagen fiber, it preferably contains an iminium cationic moiety.

[0020] The number of cationic sites (b) in component (A) may be 0. When component (A) has cationic sites, the number of cationic sites (b) in component (A) is preferably 1 or more, more preferably 1 or more and 5 or less, even more preferably 1 or more and 4 or less, still more preferably 1 or more and 3 or less, and even more preferably 1 or more and 2 or less, from the viewpoint of improving the robustness of the modified regenerated collagen fibers. The number of cationic moieties (b) in component (A) is preferably 0 or more and 5 or less, more preferably 0 or more and 4 or less, even more preferably 0 or more and 3 or less, still more preferably 0 or more and 2 or less, and even more preferably 1 or more and 2 or less.

[0021] From the viewpoint of improving the robustness of the modified regenerated collagen fiber, the difference (ab) between the number of sulfonic acid groups (a) in component (A) and the number of cationic sites (b) in component (A) is preferably 1 or more and 5 or less, more preferably 1 or more and 4 or less, even more preferably 1 or more and 3 or less, and even more preferably 1 or more and 2 or less.

[0022] From the viewpoint of improving the dyeability and fastness of the modified regenerated collagen fiber, it is preferable that component (A) has a small number of carboxy groups, and the number of carboxy groups in component (A) is preferably 2 or less, more preferably 1 or less, and even more preferably 0.

[0023] (Requirement (1)) The acid dye (A) that satisfies the above condition (1) has a sulfonic acid group and a molecular weight of 500 or more.

[0024] When component (A) satisfies the above (1), from the viewpoint of improving the fastness of the modified regenerated collagen fibers after dyeing, the molecular weight of component (A) is preferably 520 or more, more preferably 540 or more, and is also preferably 1,500 or less, more preferably 1,200 or less, even more preferably less than 1,000, still more preferably 900 or less, even more preferably 800 or less, even more preferably 780 or less, and even more preferably 750 or less. When component (A) satisfies the above (1), the molecular weight of component (A) is preferably 500 or more and 1,500 or less, more preferably 500 or more and 1,200 or less, even more preferably 500 or more and less than 1,000, still more preferably 500 or more and 900 or less, even more preferably 500 or more and 800 or less, even more preferably 500 or more and 780 or less, even more preferably 520 or more and 750 or less, even more preferably 520 or more and 750 or less, and even more preferably 540 or more and 750 or less.

[0025] (Requirement (2)) When component (A) satisfies the above condition (2), the difference (ab) between the number of sulfonic acid groups (a) in component (A) and the number of cationic moieties (b) in component (A), divided by Mw, [(ab) / Mw], where Mw is the molecular weight of component (A) (the molecular weight in the undissociated (acid) state), is 0.0045 or less, preferably 0.0040 or less, more preferably 0.0035 or less, and even more preferably 0.0025 or less, from the viewpoint of improving the dyeability and fastness of the modified regenerated collagen fiber. This is because a smaller difference between the number of sulfonic acid groups and the number of cationic moieties per molecular weight of component (A) can reduce charge repulsion between the structural moiety derived from component (B) in the modified regenerated collagen fiber and the acid dye (A). Furthermore, when component (A) satisfies the above condition (2), [(ab) / Mw] is preferably 0.0005 or more, more preferably 0.0010 or more. When component (A) satisfies the above (2), [(ab) / Mw] is preferably 0.0005 or more and 0.0045 or less, more preferably 0.0005 or more and 0.0040 or less, even more preferably 0.0010 or more and 0.0035 or less, and still more preferably 0.0010 or more and 0.0025 or less.

[0026] When component (A) satisfies the above (2), the molecular weight Mw is preferably 250 or more, more preferably 280 or more, even more preferably 300 or more, and still more preferably 320 or more. Also, it is preferably 1,500 or less, more preferably 1,200 or less, even more preferably less than 1,000, still more preferably 900 or less, even more preferably 800 or less, even more preferably 780 or less, and still more preferably 750 or less. When component (A) satisfies the above (2), the molecular weight Mw is preferably 250 or more and 1,500 or less, more preferably 250 or more and 1,200 or less, even more preferably 250 or more and less than 1,000, still more preferably 250 or more and 900 or less, still more preferably 280 or more and 800 or less, still more preferably 280 or more and 780 or less, still more preferably 280 or more and 750 or less, still more preferably 300 or more and 750 or less, and still more preferably 320 or more and 750 or less.

[0027] Component (A) may satisfy both (1) and (2) above, in which case the molecular weight of component (A) is 500 or more and [(ab) / Mw] is 0.0045 or less. The preferred ranges of the molecular weight and [(ab) / Mw] of component (A) are the same as those described above.

[0028] From the viewpoint of improving the dyeability and fastness of the modified regenerated collagen fiber, the acid dye, component (A) used in the present invention, is preferably Acid Black 52 (Color Index No. 15711), Acid Green 1 (Color Index No. 10020), Food Black 1 (Color Index No. 28440), Food Green 3 (Color Index No. 42053), Acid Green 5 (Color Index No. 42095), Acid Blue 9 (Color Index No. 42090), Acid Blue 5 (Color Index No. 42052), Acid Green 3 (Color Index No. 42085), Acid Green 25 (Color Index No. 61570), Acid Brown 13 (Color Index No. 10410), Acid Red 52 (Color Index No. 45100), Acid Black 1 (Color Index No. 20470), Acid Red 18 (Color Index No. 10410 ... Green 25 (Color Index No. 61570), Acid Brown 13 (Color Index No. 10410), Acid Red 25 (Color Index No No.16255), Acid Red 27(Color Index No.16185), Acid Blue 3(Color Index No.42051), Acid Green 50(Color Index No.44090), Acid Red 73(Color Index No.27290), Acid Blue 1(Color Index No.42045), Acid Red 184(Color Index No.15685), Acid Red 35(Color Index No.18065), Acid Red 14(Color Index No.14720), Food Red 6(Color Index No.16155), Acid Orange 3(Color Index No.10385), Acid Orange 24(Color Index No.20170), Acid Violet 43(Color Index No.60730), Acid Blue 62(Color Index No.62045), Acid Red 88(Color Index No.15620)、Acid Yellow 11(Color Index No.18820)、Acid Yellow 36(Color Index No.13065)、Acid Yellow 1(Color Index No.10316)、Acid Orange 7(Color Index No.15510)、Acid Orange 20(Color Index No.14600)、Acid Orange 6(Color Index No.14270)、Food Red 17(Color Index No.16035)、Acid Red 41(Color Index No.16290)、Acid Red 1(Color Index No.18050)、Acid Red 155(Color Index No.18130)、Acid Red 180(Color Index No.18736)、Acid Yellow 17(Color Index No.18965)、Acid Yellow 23(Color Index No.19140)、Acid Red 163(Color Index No.24790)、Food Black 2(Color Index No.27755)、Direct Orange 39(Color Index No.40215)、Acid Blue 7(Color Index No.42080)、Acid Green 9(Color Index No.42100)、Acid Green 22(Color Index No.42170)、Acid Blue 104(Color Index No.42735)、Acid Violet 9(Color Index No.45190)、Acid Red 50(Color Index No.45220)、Acid Violet 50(Color Index No.50325)、Acid Black 2(Color Index No.50420)、Acid Blue 80(Color Index No.61585)、Acid Blue 87(Color Index No.74180)、Acid Red 195(Color Index No.18760)、Acid Red 249(Color Index No.The color may include one or more selected from the group consisting of Acid Red 131, Acid Red 337 (Color Index No. 17102), Acid Red 18134, Acid Red 131, and Acid Red 337 (Color Index No. 17102). Details of these acid dyes are shown in Table 1.

[0029] [Table 1]

[0030] Component (A) is more preferably Acid Black 52 (Color Index No. 15711), Acid Green 1 (Color Index No. 10020), Food Black 1 (Color Index No. 28440), Food Green 3 (Color Index No. 42053), Acid Green 5 (Color Index No. 42095), Acid Blue 9 (Color Index). No.42090), Acid Blue 5(Color Index No.42052), Acid Green 3(Color Index No.42085), Acid Green 25(Color Index No.61570), Acid Brown 13(Color Index No.10410), Acid Red 52(Color Index No.45100), Acid Black 1(Color Index No.20470), Acid Red 18(Color Index No.16255), Acid Red 27(Color Index No. 16185), Acid Blue 3 (Color Index No. 42051), Acid Green 50 (Color Index No. 44090), Acid Red 73 (Color Index No. 27290), Acid Blue 1 (Color Index No. 42045), Acid Blue 7 (Color Index No. 42080), Acid Green 9 (Color Index No. 42100), Acid Blue 104 (Color Index No. 42735), and Acid Violet 50 (Color Index No. 50325).

[0031] Among the above, from the viewpoint of improving the robustness of the modified regenerated collagen fibers, component (A) more preferably contains one or more selected from the group consisting of Food Green 3 (Color Index No. 42053), Acid Green 5 (Color Index No. 42095), Acid Blue 9 (Color Index No. 42090), Acid Blue 5 (Color Index No. 42052), Acid Green 3 (Color Index No. 42085), Acid Red 52 (Color Index No. 45100), Acid Blue 3 (Color Index No. 42051), Acid Green 50 (Color Index No. 44090), and Acid Blue 1 (Color Index No. 42045), which have a cationic moiety number (b) of 1 or more, and even more preferably contains one or more selected from the group consisting of Acid Blue 9 and Acid Red 52.

[0032] The dye composition may contain dyes other than component (A), but from the viewpoint of improving the dyeability and fastness of the modified regenerated collagen fiber, the content of component (A) in all acid dyes in the dye composition is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more, but 100% by mass or less.

[0033] From the viewpoint of improving the dyeability and fastness of the modified regenerated collagen fibers, the content of component (A) in the dye composition is preferably 0.001% by mass or more, more preferably 0.002% by mass or more, even more preferably 0.005% by mass or more, still more preferably 0.01% by mass or more, still more preferably 0.02% by mass or more, still more preferably 0.03% by mass or more, and still more preferably 0.05% by mass or more, and from the viewpoint of improving formulation stability, it is preferably 3.0% by mass or less, more preferably 1.0% by mass or less, still more preferably 0.8% by mass or less, still more preferably 0.6% by mass or less, still more preferably 0.5% by mass or less, still more preferably 0.2% by mass or less, and still more preferably 0.1% by mass or less. The content of component (A) in the stain composition is preferably 0.001% by mass or more and 3.0% by mass or less, more preferably 0.002% by mass or more and 3.0% by mass or less, even more preferably 0.005% by mass or more and 1.0% by mass or less, still more preferably 0.01% by mass or more and 0.8% by mass or less, still more preferably 0.02% by mass or more and 0.6% by mass or less, still more preferably 0.03% by mass or more and 0.5% by mass or less, and still more preferably 0.05% by mass or more and 0.2% by mass or less. The content of component (A) in the stain composition may also be 0.03% by mass or more and 0.1% by mass or less.

[0034] The dye composition may further contain a dye other than the acid dye, however, from the viewpoint of improving the dyeability and fastness of the modified regenerated collagen fiber, the content of the dye other than the acid dye in the dye composition is preferably 0.1% by mass or less, more preferably 0.05% by mass or less, even more preferably 0.02% by mass or less, still more preferably 0.01% by mass or less, even more preferably 0.001% by mass or less, still more preferably 0.0001% by mass or less, and may even be 0% by mass.

[0035] <Water> The water used in the composition of the present invention is not particularly limited, and for example, ion-exchanged water, pure water, distilled water, etc. can be used. From the viewpoint of improving the dyeability and fastness of the modified regenerated collagen fibers, the water content in the dye composition is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 85% by mass or more, and is preferably 99.999% by mass or less. The content of water in the dye composition may be the balance of the acid dye.

[0036] <Other ingredients> In addition to the above components, the dye composition may contain antioxidants, fragrances, preservatives, thickeners, pH adjusters, surfactants, polymers, and the like.

[0037] <ph> The pH of the dye composition is preferably 2.0 or higher, more preferably 2.2 or higher, and even more preferably 2.5 or higher. From the viewpoint of improving the dyeability and fastness of the modified regenerated collagen fibers, the pH is preferably 6 or lower, more preferably 5 or lower, and even more preferably 4 or lower. The pH of the dye composition is preferably 2.0 or higher and 6 or lower, more preferably 2.2 or higher and 5 or lower, and even more preferably 2.5 or higher and 4 or lower. The pH can be measured at 25°C by the method described in the Examples.

[0038] <Dosage form, manufacturing method> The formulation of the dye composition is not particularly limited, and can be liquid, paste, cream, gel, foam, spray, wax, or other formulation depending on the product form, with liquid being preferred. The method for producing the stain composition is not particularly limited, and the stain composition can be produced by mixing the components by any method. The stain composition of the present embodiment can be preferably obtained by mixing a medium (e.g., water) and other components under heating (e.g., 60 to 80°C) to dissolve them uniformly, and then adding component (A) and mixing them uniformly.

[0039] <Modified regenerated collagen fiber> The regenerated collagen fibers to be dyed with the dye composition of the present invention include modified regenerated collagen fibers containing one or more compounds (B) selected from the group consisting of the following components (B1) and (B2): (B1) Benzoic acid or its salts (B2) 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.

[0040] (Component (B)) Component (B) is one or more compounds selected from the group consisting of components (B1) and (B2), and is a modifier for regenerated collagen fibers. The regenerated collagen fibers to be modified by component (B) will be described later.

[0041] [Component (B1)] Component (B1) is benzoic acid or a salt thereof. When component (B1) is a salt, examples thereof include alkali metal salts such as sodium salts and potassium salts. Specific examples of component (B1) include one or more selected from the group consisting of benzoic acid, sodium benzoate, and potassium benzoate, and preferably include one or more selected from the group consisting of benzoic acid and sodium benzoate.

[0042] [Component (B2)] Component (B2) 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.

[0043] In component (B2), 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.

[0044] The structural unit derived from an aromatic vinyl compound in component (B2) 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.

[0045] In component (B2), the bonding state of the monomers that give rise to each structural unit may be block bonding, random bonding, or a combination thereof.

[0046] Component (B2) 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.

[0047] A suitable embodiment of component (B2) 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 the component (B2), from the viewpoint of further improving dyeability and fastness when dyeing with the dye composition of the present invention, preferably include 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, and more preferably include a styrene-maleic acid copolymer.

[0048] In component (B2), 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, from the viewpoint of improving the dyeability and fastness of the modified regenerated collagen fiber.

[0049] The acid value of component (B2) is 100 mgKOH / g or more, and from the viewpoint of further improving dyeability and fastness when dyed with the dye 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 (B2) 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, still 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.

[0050] Specific examples of component (B2) 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

[0051] Component (B2) has a weight-average molecular weight of 1,500 or more and 15,000 or less, and from the viewpoint of further improving fastness when dyed with the dye composition of the present invention, it is preferably 3,000 or more, more preferably 5,000 or more, even more preferably 6,000 or more, and preferably 10,000 or less, more preferably 9,500 or less, even more preferably 9,000 or less. The weight-average molecular weight of component (B2) is preferably 1,500 or more and 10,000 or less, more preferably 3,000 or more and 10,000 or less, even more preferably 5,000 or more and 9,500 or less, and even more preferably 6,000 or more and 9,000 or less. The weight-average molecular weight of component (B2) may also be preferably 3,000 or more and 15,000 or less, more preferably 5,000 or more and 15,000 or less, even more preferably 6,000 or more and 10,000 or less. In this specification, the term "weight average molecular weight" refers to the 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.

[0052] Component (B) can be used alone or in combination of two or more. Among the above, from the viewpoint of further improving fastness when dyed with the dye composition of the present invention, component (B) preferably contains one or more selected from the group consisting of benzoic acid, sodium benzoate, and a styrene-maleic acid copolymer, and more preferably contains a styrene-maleic acid copolymer.

[0053] (Content of component (B)) From the viewpoint of further improving dyeability and fastness when dyed with the dye composition of the present invention, the content of component (B) in the modified regenerated collagen fiber 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, even more preferably 5.0% by mass or more, even more preferably 10% by mass or more, even more preferably 15% by mass or more, even 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, even more preferably 55% by mass or less, even more preferably 50% by mass or less, even more preferably 45% by mass or less, and even 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.

[0054] When the modified regenerated collagen fibers contain component (B1) as component (B), the content of component (B1) in the modified regenerated collagen fibers means the content converted into benzoic acid.

[0055] The content of component (B) in modified regenerated collagen fibers can be measured by the following method. First, an appropriate solvent that does not decompose component (B) and can dissolve the regenerated collagen fibers is selected, and the fibers are dissolved and extracted. Then, 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 HPLC / UV or GPC / UV, and the content of component (B) is calculated from the peak area. Specifically, the content of component (B) in modified regenerated collagen fibers can be measured by the method described in the Examples.

[0056] The dye composition of the present invention may be adjusted in terms of the mass ratio [(B) / (A)] of component (B) in the fiber for head accessories to component (A) in the dye composition, depending on the mode of use. For example, when the dye composition is a coat-type dye, the mass ratio of component (B) in the fiber for head accessories to component (A) in the dye composition [(B) / (A)] is, from the viewpoints of dye compatibility and dye levelness, preferably 5 or more, more preferably 10 or more, even more preferably 20 or more, still more preferably 50 or more, still more preferably 100 or more, and still more preferably 200 or more; and from the viewpoints of dyeability, storage stability and dye levelness of the dye composition, it can be set to preferably 20,000 or less, more preferably 10,000 or less, even more preferably 5,000 or less, still more preferably 2,000 or less, still more preferably 1,000 or less, still more preferably 700 or less, still more preferably 500 or less, and still more preferably 400 or less. That is, the mass ratio [(B) / (A)] is preferably 5 or more and 20,000 or less, more preferably 10 or more and 10,000 or less, even more preferably 20 or more and 5,000 or less, still more preferably 50 or more and 2,000 or less, still more preferably 100 or more and 1,000 or less, still more preferably 100 or more and 700 or less, still more preferably 100 or more and 500 or less, and still more preferably 200 or more and 400 or less. Furthermore, when the dye composition is a dip-type dye, the mass ratio of component (B) in the fiber for head accessories to component (A) in the dye composition [(B) / (A)] is, from the viewpoints of dye compatibility, storage stability and dye levelness of the dye composition, preferably 0.1 or more, more preferably 1 or more, even more preferably 2 or more, still more preferably 5 or more, still more preferably 7 or more, and still more preferably 10 or more; and from the viewpoints of dyeability and dye levelness, it can be set to preferably 3000 or less, more preferably 1500 or less, even more preferably 750 or less, still more preferably 500 or less, still more preferably 300 or less, still more preferably 100 or less, and still more preferably 60 or less. That is, the mass ratio [(B) / (A)] is preferably 0.1 or more and 3000 or less, more preferably 1 or more and 1500 or less, even more preferably 2 or more and 750 or less, still more preferably 5 or more and 500 or less, still more preferably 7 or more and 300 or less, still more preferably 7 or more and 100 or less, and still more preferably 10 or more and 60 or less.

[0057] (Component (C): Polyvalent metal, its salt, or its complex) In order to firmly coordinate component (B) inside the fiber and further improve dyeability and fastness when dyed with the dye 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 dyeability and fastness when dyeing with the dye 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.

[0058] 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 dyeability and fastness when dyed with the dye 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.

[0059] The dye composition of the present invention may be adjusted in terms of the mass ratio [(C) / (A)] of component (C) in the fiber for head accessories to the basic dye in the dye composition, depending on the mode of use. For example, when the dye composition is a coating type and is applied to regenerated collagen fibers, the mass ratio of component (C) in the fiber for head accessories to component (A) in the dye composition [(C) / (A)] is preferably 0.3 or more, more preferably 1 or more, even more preferably 2 or more, still more preferably 5 or more, still more preferably 10 or more, and still more preferably 25 or more, from the viewpoints of dye compatibility, storage stability, and dye levelness of the dye composition, and can be preferably 5000 or less, more preferably 2500 or less, even more preferably 1000 or less, still more preferably 500 or less, still more preferably 200 or less, and still more preferably 100 or less, from the viewpoints of dyeability and dye levelness. That is, the mass ratio [(C) / (A)] is preferably 0.3 or more and 5000 or less, more preferably 1 or more and 2500 or less, even more preferably 2 or more and 1000 or less, still more preferably 5 or more and 500 or less, still more preferably 10 or more and 200 or less, and still more preferably 25 or more and 100 or less. Furthermore, when the dye composition is a dip-type dye, the mass ratio of component (C) in the fiber for head accessories to component (A) in the dye composition [(C) / (A)] is, from the viewpoints of dye compatibility, storage stability and dye levelness of the dye composition, preferably 0.04 or more, more preferably 0.1 or more, even more preferably 0.2 or more, still more preferably 0.5 or more, still more preferably 1.0 or more, still more preferably 1.5 or more, and still more preferably 3 or more; and, from the viewpoints of dyeability and dye levelness, it can be set to preferably 750 or less, more preferably 500 or less, still more preferably 150 or less, still more preferably 75 or less, still more preferably 20 or less, still more preferably 15 or less, and still more preferably 12 or less. That is, the mass ratio [(C) / (A)] is preferably 0.04 or more and 750 or less, more preferably 0.1 or more and 500 or less, even more preferably 0.2 or more and 150 or less, still more preferably 0.5 or more and 75 or less, still more preferably 1.0 or more and 20 or less, still more preferably 1.5 or more and 15 or less, still more preferably 1.5 or more and 12 or less, and still more preferably 3 or more and 12 or less.

[0060] (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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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 while stirring, 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, spinnability, coloration prevention, and preservative properties.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] [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.

[0074] The content of the polyvalent metal salt and polyvalent metal complex in the fiber treatment agent is preferably 0.3 mass % or more and 5 mass % or less in terms of polyvalent metal oxide (aluminum oxide when the polyvalent metal is aluminum).

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] After treating the undried regenerated collagen fibers with an epoxy compound and / or the fiber treatment agent, the fibers may be washed with water, for example, by washing with running water for 10 minutes to 4 hours.

[0081] [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 can be dyed with the dye composition of the present invention.

[0082] From the viewpoint of improving penetration into fibers and improving treatment effects, 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, and preferably 60% by mass or less, more preferably 40% by mass or less, and even more preferably 35% 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, and still more preferably 3.0% by mass or more and 35% by mass or less.

[0083] When component (B1) is used as component (B), the content of component (B1) in the fiber treatment agent, calculated as benzoic acid, is even more preferably 5.0% by mass or more, even more preferably 10% by mass or more, even more preferably 15% by mass or more, even more preferably 20% by mass or more, and even more preferably 30% by mass or less, from the viewpoints of improving penetration into fibers and improving the treatment effect. When component (B1) is used as component (B), the content of component (B1) in the fiber treatment agent, calculated as benzoic acid, 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 5.0% by mass or more and 30% by mass or less, still more preferably 10% by mass or more and 30% by mass or less, still more preferably 15% by mass or more and 30% by mass or less, and still more preferably 20% by mass or more and 30% by mass or less.

[0084] When component (B2) is used as component (B), the content of component (B2) in the fiber treatment agent is even more preferably 4.0% by mass or more, and even more preferably 30% by mass or less, even more preferably 20% by mass or less, even more preferably 10% by mass or less, and even more preferably 5.0% by mass or less, from the viewpoint of improving penetration into fibers and improving the treatment effect. When component (B2) is used as component (B), the content of component (B2) 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 5.0% by mass or less.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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).

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] When component (B2) is used as component (B), the treatment with the fiber treatment agent containing component (B2) 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 (B2). (2) A step of removing the fibers immersed in the fiber treatment agent in (1) and rinsing them with water.

[0095] 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.

[0096] 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.

[0097] The number of treatments with the fiber treatment agent containing component (B2) is preferably 2 to 5 times, more preferably 2 to 3 times, from the viewpoint of improving the treatment effect and productivity. 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 is preferably 48 hours or shorter, more preferably 33 hours or shorter, and even more preferably 20 hours or shorter, from the viewpoint of suppressing damage to the fibers.

[0098] 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. When modified regenerated collagen fibers are dyed using the dye composition of the present invention, the acid dye (A) tends to remain in the modified regenerated collagen fibers, which is thought to improve fastness.

[0099] The regenerated collagen fibers to be dyed with the dye composition of the present invention may be fibers that contain at least a portion of the modified regenerated collagen fibers, or may be fibers consisting solely of modified regenerated collagen fibers. From the viewpoint of further improving fastness, the regenerated collagen fibers to be dyed with the dye composition of the present invention are preferably fibers consisting solely of modified regenerated collagen fibers.

[0100] [Dyeing method] The present invention provides a method for dyeing regenerated collagen fibers, comprising the steps of: The dyeing method includes a step of applying a dye composition for regenerated collagen fibers to the regenerated collagen fibers, The dye composition contains the following component (A) and water, The present invention provides a method for dyeing regenerated collagen fibers, wherein the regenerated collagen fibers include modified regenerated collagen fibers containing the following component (B): (A) An acid dye having a sulfonic acid group and satisfying at least one of the following conditions (1) and (2): (1) Molecular weight of 500 or more (2) When the molecular weight is Mw, the difference (ab) between the number of sulfonic acid groups (a) and the number of cationic sites (b) divided by Mw [(ab) / Mw] is 0.0045 or less. (B) One or more compounds selected from the group consisting of the following components (B1) and (B2): (B1) Benzoic acid or its salts (B2) 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 dyeing regenerated collagen fibers will also be simply referred to as the "dyeing method of the present invention."

[0101] The regenerated collagen fibers, the dye composition, and their preferred embodiments are the same as those described in the dye composition for regenerated collagen fibers.

[0102] The method of the present invention includes a step of applying the regenerated collagen fiber dye composition to the regenerated collagen fiber. The method for applying the dye composition for regenerated collagen fibers to regenerated collagen fibers may be any method that can bring the dye composition into contact with the regenerated collagen fibers, and examples thereof include a method of applying the composition to regenerated collagen fibers in a dry or wet state, and a method of immersing regenerated collagen fibers in the composition. Among the above, the method of applying the dye composition to regenerated collagen fibers in a dry state, or the method of immersing regenerated collagen fibers in a dry state in the dye composition is preferred. From the viewpoint of a balance between dyeability, fastness, and economy, the amount of dye composition applied to the regenerated collagen fibers is preferably a bath ratio (dry mass of regenerated collagen fibers:mass of dye composition) of 1:0.2 to 1:500, where 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. When the dye composition is applied to the regenerated collagen fibers, the amount of the dye composition to be applied to the regenerated collagen fibers, 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, is preferably 1:0.2 to 1:200 in terms of the bath ratio (dry mass of regenerated collagen fibers:mass of dye composition), even more preferably 1:0.2 to 1:100, even more preferably 1:0.2 to 1:50, even more preferably 1:0.2 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 1:0.8 to 1:3. Furthermore, when regenerated collagen fibers are immersed in the dye composition, the bath ratio (dry mass of regenerated collagen fibers:mass of dye composition) is more preferably 1:2 to 1:500, even more preferably 1:3 to 1:250, still more preferably 1:5 to 1:100, even more preferably 1:10 to 1:50, and still more preferably 1:10 to 1:20, 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.

[0103] In addition, in this process, the dyeing conditions for the fiber for headwear products may be set using the mass ratio [(B) / (A)] of component (B) in the fiber for headwear products to component (A) in the dye composition as an index. Specifically, for example, when the dye composition is applied to regenerated collagen fibers, the mass ratio of component (B) in the fiber for headwear products to component (A) in the dye composition [(B) / (A)] is, from the viewpoints of dye compatibility and dye levelness, preferably 5 or more, more preferably 10 or more, even more preferably 20 or more, still more preferably 50 or more, still more preferably 100 or more, and still more preferably 200 or more; and from the viewpoints of dyeability, storage stability and dye levelness of the dye composition, this step may be performed under conditions such that the mass ratio is preferably 20,000 or less, more preferably 10,000 or less, even more preferably 5,000 or less, still more preferably 2,000 or less, still more preferably 1,000 or less, still more preferably 700 or less, still more preferably 500 or less, and still more preferably 400 or less. That is, the mass ratio [(B) / (A)] is preferably 5 or more and 20,000 or less, more preferably 10 or more and 10,000 or less, even more preferably 20 or more and 5,000 or less, still more preferably 50 or more and 2,000 or less, still more preferably 100 or more and 1,000 or less, still more preferably 100 or more and 700 or less, still more preferably 100 or more and 500 or less, and still more preferably 200 or more and 400 or less. On the other hand, when regenerated collagen fibers are immersed in the dye composition, this step may be carried out under conditions such that the mass ratio [(B) / (A)] of component (B) in the fiber for headwear products to component (A) in the dye composition is preferably 0.1 or more, more preferably 1 or more, even more preferably 2 or more, still more preferably 5 or more, still more preferably 7 or more, and still more preferably 10 or more, from the viewpoints of dye compatibility, storage stability, and dye levelness of the dye composition; and is preferably 3000 or less, more preferably 1500 or less, even more preferably 750 or less, still more preferably 500 or less, still more preferably 300 or less, still more preferably 100 or less, and still more preferably 60 or less, from the viewpoints of dyeability and dye levelness. That is, the mass ratio [(B) / (A)] is preferably 0.1 or more and 3000 or less, more preferably 1 or more and 1500 or less, even more preferably 2 or more and 750 or less, still more preferably 5 or more and 500 or less, still more preferably 7 or more and 300 or less, still more preferably 7 or more and 100 or less, and still more preferably 10 or more and 60 or less.

[0104] Furthermore, the dyeing conditions for the fiber for headwear can be set using the mass ratio [(C) / (A)] of component (C) in the fiber for headwear to the basic dye in the dye composition as an index. Specifically, for example, when the dye composition is applied to regenerated collagen fibers, the mass ratio of component (C) in the fiber for head accessories to component (A) in the dye composition [(C) / (A)] is preferably 0.3 or more, more preferably 1 or more, even more preferably 2 or more, still more preferably 5 or more, even more preferably 10 or more, and still more preferably 25 or more, from the viewpoints of dye compatibility, storage stability, and dye levelness of the dye composition, and from the viewpoints of dyeability and dye levelness, is preferably 5000 or less, more preferably 2500 or less, even more preferably 1000 or less, still more preferably 500 or less, still more preferably 200 or less, and still more preferably 100 or less. That is, this mass ratio [(C) / (A)] is preferably 0.3 or more and 5000 or less, more preferably 1 or more and 2500 or less, even more preferably 2 or more and 1000 or less, still more preferably 5 or more and 500 or less, still more preferably 10 or more and 200 or less, and still more preferably 25 or more and 100 or less. On the other hand, when regenerated collagen fibers are immersed in the dye composition, this step can be carried out under conditions such that the mass ratio [(C) / (A)] of component (C) in the fiber for headwear to component (A) in the dye composition is preferably 0.04 or more, more preferably 0.1 or more, even more preferably 0.2 or more, still more preferably 0.5 or more, still more preferably 1.0 or more, still more preferably 1.5 or more, and still more preferably 3 or more, from the viewpoints of dye compatibility, storage stability, and dye levelness of the dye composition; and further, from the viewpoints of dyeability and dye levelness, it is preferably 750 or less, more preferably 500 or less, even more preferably 150 or less, still more preferably 75 or less, still more preferably 20 or less, still more preferably 15 or less, and still more preferably 12 or less. That is, the mass ratio [(C) / (A)] is preferably 0.04 or more and 750 or less, more preferably 0.1 or more and 500 or less, even more preferably 0.2 or more and 150 or less, still more preferably 0.5 or more and 75 or less, still more preferably 1.0 or more and 20 or less, still more preferably 1.5 or more and 15 or less, still more preferably 1.5 or more and 12 or less, and still more preferably 3 or more and 12 or less.

[0105] When the dye composition is applied to regenerated collagen fibers, the application time is preferably 10 seconds or more, more preferably 20 seconds or more, from the viewpoint of further improving dyeability and fastness, and is preferably 10 minutes or less, more preferably 5 minutes or less, from the viewpoint of improving productivity. When the dye composition is applied to 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.

[0106] After applying the dye 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 dyeability and fastness, 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 improving productivity. 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.

[0107] When regenerated collagen fibers are immersed in the dye composition, the immersion time is preferably 10 seconds or more, more preferably 30 seconds or more, from the viewpoint of further improving dyeability and fastness, and is preferably 3 hours or less, more preferably 2 hours or less, and even more preferably 1 hour 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 1 hour or less.

[0108] The temperature when the dye composition is applied to the regenerated collagen fibers is not particularly limited, but from the viewpoints of improving the handleability of the dye composition and suppressing thermal shrinkage of the regenerated collagen fibers, it is preferably 40°C or lower, more preferably 35°C or lower. Furthermore, from the viewpoint of further improving dyeability and fastness, it is preferably 5°C or higher, more preferably 10°C or higher. The temperature when the dye composition is applied to the regenerated collagen fibers is preferably 5°C or higher and 40°C or lower, more preferably 10°C or higher and 35°C or lower.

[0109] The dyeing method of the present invention preferably includes a step of rinsing the dye composition applied to the regenerated collagen fibers after applying the dye composition to the regenerated collagen fibers (hereinafter simply referred to as the "rinsing step"). The rinsing step is carried out, for example, by rinsing the dye 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.

[0110] The dyeing 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 dye 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 to actively reduce the moisture content of the regenerated collagen fibers.

[0111] [Colored modified regenerated collagen fiber] The present invention further provides colored modified regenerated collagen fibers containing the following components (A) and (B): (A) An acid dye having a sulfonic acid group and satisfying at least one of the following conditions (1) and (2): (1) Molecular weight of 500 or more (2) When the molecular weight is Mw, the difference (ab) between the number of sulfonic acid groups (a) and the number of cationic sites (b) divided by Mw [(ab) / Mw] is 0.0045 or less. (B) One or more compounds selected from the group consisting of the following components (B1) and (B2): (B1) Benzoic acid or its salts (B2) 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.

[0112] The colored modified regenerated collagen fibers are modified regenerated collagen fibers that have been modified with the component (B) and then colored with the component (A). From the viewpoint of further improving dyeability and fastness, the colored modified regenerated collagen fibers preferably further contain the component (C): a polyvalent metal, a salt thereof, or a complex thereof.

[0113] The colored modified regenerated collagen fiber of the present invention is preferably one in which the mass ratio [(B) / (A)] of component (B) in the fiber for headwear products to component (A) in the dye composition is controlled depending on the coloring method. That is, when the fiber is colored by application, the mass ratio of component (B) in the fiber for head accessories to component (A) in the dye composition [(B) / (A)] is, from the viewpoints of dye compatibility and dye levelness, preferably 5 or more, more preferably 10 or more, even more preferably 20 or more, still more preferably 50 or more, still more preferably 100 or more, and still more preferably 200 or more; and, from the viewpoints of dyeability, storage stability and dye levelness of the dye composition, it is preferably 20,000 or less, more preferably 10,000 or less, even more preferably 5,000 or less, still more preferably 2,000 or less, still more preferably 1,000 or less, still more preferably 700 or less, still more preferably 500 or less, and still more preferably 400 or less. That is, the mass ratio [(B) / (A)] is preferably 5 or more and 20,000 or less, more preferably 10 or more and 10,000 or less, even more preferably 20 or more and 5,000 or less, still more preferably 50 or more and 2,000 or less, still more preferably 100 or more and 1,000 or less, still more preferably 100 or more and 700 or less, still more preferably 100 or more and 500 or less, and still more preferably 200 or more and 400 or less. On the other hand, when the fiber is colored by immersion, the mass ratio [(B) / (A)] of component (B) in the fiber for head accessories to component (A) in the dye composition is preferably 0.1 or more, more preferably 1 or more, even more preferably 2 or more, still more preferably 5 or more, still more preferably 7 or more, and still more preferably 10 or more, from the viewpoints of dye compatibility, storage stability, and dye levelness of the dye composition, and is preferably 3000 or less, more preferably 1500 or less, even more preferably 750 or less, still more preferably 500 or less, still more preferably 300 or less, still more preferably 100 or less, and still more preferably 60 or less, from the viewpoints of dyeability and dye levelness. That is, the mass ratio [(B) / (A)] is preferably 0.1 or more and 3000 or less, more preferably 1 or more and 1500 or less, even more preferably 2 or more and 750 or less, still more preferably 5 or more and 500 or less, still more preferably 7 or more and 300 or less, still more preferably 7 or more and 100 or less, and still more preferably 10 or more and 60 or less.

[0114] Furthermore, the colored modified regenerated collagen fiber of the present invention is preferably one in which the mass ratio [(C) / (A)] of component (C) in the fiber for headwear products to component (A) in the dye composition is controlled depending on the coloring method. That is, in the case of fibers that are colored by application, when the dye composition is applied to the regenerated collagen fibers, the mass ratio of component (C) in the fiber for head accessories to component (A) in the dye composition [(C) / (A)] is, from the viewpoints of dye compatibility, storage stability, and dye levelness of the dye composition, preferably 0.3 or more, more preferably 1 or more, even more preferably 2 or more, still more preferably 5 or more, still more preferably 10 or more, and still more preferably 25 or more, and from the viewpoints of dyeability and dye levelness, is preferably 5000 or less, more preferably 2500 or less, even more preferably 1000 or less, still more preferably 500 or less, still more preferably 200 or less, and still more preferably 100 or less. That is, the mass ratio [(C) / (A)] is preferably 0.3 or more and 5000 or less, more preferably 1 or more and 2500 or less, even more preferably 2 or more and 1000 or less, still more preferably 5 or more and 500 or less, still more preferably 10 or more and 200 or less, and still more preferably 25 or more and 100 or less. On the other hand, when the fiber is colored by immersion, the mass ratio of component (C) in the fiber for head accessories to component (A) in the dye composition [(C) / (A)] is, from the viewpoints of dye compatibility, storage stability, and dye levelness of the dye composition, preferably 0.04 or more, more preferably 0.1 or more, even more preferably 0.2 or more, still more preferably 0.5 or more, still more preferably 1.0 or more, still more preferably 1.5 or more, and still more preferably 3 or more; and, from the viewpoints of dyeability and dye levelness, is preferably 750 or less, more preferably 500 or less, still more preferably 150 or less, still more preferably 75 or less, still more preferably 20 or less, still more preferably 15 or less, and still more preferably 12 or less. That is, the mass ratio [(C) / (A)] is preferably 0.04 or more and 750 or less, more preferably 0.1 or more and 500 or less, even more preferably 0.2 or more and 150 or less, still more preferably 0.5 or more and 75 or less, still more preferably 1.0 or more and 20 or less, still more preferably 1.5 or more and 15 or less, still more preferably 1.5 or more and 12 or less, and still more preferably 3 or more and 12 or less.

[0115] The colored modified regenerated collagen fibers can be obtained by preferably preparing modified regenerated collagen fibers containing one or more compounds (B) selected from the group consisting of component (B1) and component (B2) using the method described above, and then applying the dye composition for regenerated collagen fibers to the modified regenerated collagen fibers to dye them. The modified regenerated collagen fibers can preferably be dyed using the dyeing method of the present invention.

[0116] [Headdress products] The colored modified regenerated collagen fibers can be suitably used for head accessories. 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 for the above-mentioned head accessories. The head accessories may contain, at least in part, colored fibers for head accessories. In this application, fibers for head accessories also include human hair.

[0117] With respect to the above-mentioned embodiments, the present invention discloses the following. <1> A dye composition for regenerated collagen fibers, comprising: The dye composition contains the following component (A) and water, A dye composition for regenerated collagen fibers, wherein the regenerated collagen fibers comprise modified regenerated collagen fibers containing the following component (B): (A) An acid dye having a sulfonic acid group and satisfying at least one of the following conditions (1) and (2): (1) Molecular weight of 500 or more (2) When the molecular weight is Mw, the difference (ab) between the number of sulfonic acid groups (a) and the number of cationic sites (b) divided by Mw [(ab) / Mw] is 0.0045 or less. (B) One or more compounds selected from the group consisting of the following components (B1) and (B2): (B1) Benzoic acid or its salts (B2) 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 number (a) of sulfonic acid groups in the component (A) is preferably 1 or more and 6 or less, more preferably 1 or more and 5 or less, even more preferably 1 or more and 4 or less, still more preferably 1 or more and 3 or less, and still more preferably 2 or more and 3 or less. <1> A dye composition for regenerated collagen fibers. <3> the cationic moiety comprises at least one selected from the group consisting of a quaternary ammonium cationic moiety and an iminium cationic moiety, and preferably comprises an iminium cationic moiety; <1> or <2> A dye composition for regenerated collagen fibers. <4> The number (b) of cationic moieties in the component (A) is preferably 0 or more and 5 or less, more preferably 0 or more and 4 or less, even more preferably 0 or more and 3 or less, still more preferably 0 or more and 2 or less, and still more preferably 1 or more and 2 or less. <1> ~ <3> Any one of the above dye compositions for regenerated collagen fibers. <5> the difference (ab) between the number of sulfonic acid groups (a) in the component (A) and the number of cationic sites (b) in the component (A) is preferably 1 or more and 5 or less, more preferably 1 or more and 4 or less, even more preferably 1 or more and 3 or less, and still more preferably 1 or more and 2 or less; <1> ~ <4> Any one of the above dye compositions for regenerated collagen fibers. <6> When the component (A) satisfies the above (1), the molecular weight of the component (A) is preferably 500 or more and 1,500 or less, more preferably 500 or more and 1,200 or less, even more preferably 500 or more and less than 1,000, still more preferably 500 or more and 900 or less, still more preferably 500 or more and 800 or less, still more preferably 500 or more and 780 or less, still more preferably 520 or more and 750 or less, still more preferably 520 or more and 750 or less, and still more preferably 540 or more and 750 or less. <1> ~ <5> Any one of the above dye compositions for regenerated collagen fibers. <7> When the component (A) satisfies the condition (2), [(ab) / Mw] is preferably 0.0005 or more and 0.0045 or less, more preferably 0.0005 or more and 0.0040 or less, even more preferably 0.0010 or more and 0.0035 or less, and still more preferably 0.0010 or more and 0.0025 or less. <1> ~ <6> Any one of the above dye compositions for regenerated collagen fibers. <8> When the component (A) satisfies the above (2), the molecular weight Mw is preferably 250 or more and 1,500 or less, more preferably 250 or more and 1,200 or less, 250 or more and even more preferably less than 1,000, still more preferably 250 or more and 900 or less, still more preferably 280 or more and 800 or less, still more preferably 280 or more and 780 or less, still more preferably 280 or more and 750 or less, still more preferably 300 or more and 750 or less, and still more preferably 320 or more and 750 or less. <1> ~ <7> Any one of the above dye compositions for regenerated collagen fibers. <9> The component (A) is preferably Acid Black 52 (Color Index No. 15711), Acid Green 1 (Color Index No. 10020), Food Black 1 (Color Index No. 28440), Food Green 3 (Color Index No. 42053), Acid Green 5 (Color Index No. 42095), Acid Blue 9 (Color Index No. 42090), Acid Blue 5 (Color Index No. 42052), Acid Green 3 (Color Index No. 42085), Acid Green 25 (Color Index No. 61570), Acid Brown 13 (Color Index No. 10410), Acid Red 52 (Color Index No. 45100), Acid Black 1 (Color Index No. 20470), Acid Red 18 (Color Index No. 16255), Acid Red 27 (Color Index No. 16185), Acid Blue 3 (Color Index No. 42051), Acid Green 50 (Color Index No. 44090), Acid Red 73 (Color Index No. 27290), Acid Blue 1 (Color Index No. 42045), Acid Red 184 (Color Index No. 15685), Acid Red 35 (Color Index No. 18065), Acid Red 14 (Color Index No. 14720), Food Red 6 (Color Index No. 16155), Acid Orange 3 (Color Index No. 10385), Acid Orange 24 (Color Index No. 20170), Acid Violet 43 (Color Index No. 60730), Acid Blue 62 (Color Index No. 62045), Acid Red 88 (Color Index No. 15620), Acid Yellow 11 (Color Index No.18820)、Acid Yellow 36(Color Index No.13065)、Acid Yellow 1(Color Index No.10316)、Acid Orange 7(Color Index No.15510)、Acid Orange 20(Color Index No.14600)、Acid Orange 6(Color Index No.14270)、Food Red 17(Color Index No.16035)、Acid Red 41(Color Index No.16290)、Acid Red 1(Color Index No.18050)、Acid Red 155(Color Index No.18130)、Acid Red 180(Color Index No.18736)、Acid Yellow 17(Color Index No.18965)、Acid Yellow 23(Color Index No.19140)、Acid Red 163(Color Index No.24790)、Food Black 2(Color Index No.27755)、Direct Orange 39(Color Index No.40215)、Acid Blue 7(Color Index No.42080)、Acid Green 9(Color Index No.42100)、Acid Green 22(Color Index No.42170)、Acid Blue 104(Color Index No.42735)、Acid Violet 9(Color Index No.45190)、Acid Red 50(Color Index No.45220)、Acid Violet 50(Color Index No.50325)、Acid Black 2(Color Index No.50420)、Acid Blue 80(Color Index No.61585)、Acid Blue 87(Color Index No.74180)、Acid Red 195(Color Index No.18760)、Acid Red 249(Color Index No.18134), Acid Red 131, and Acid Red 337 (Color Index No. 17102), <1> ~ <8> A dye composition for regenerated collagen fibers according to any one of the above. <10> The component (A) is more preferably Acid Black 52 (Color Index No. 15711), Acid Green 1 (Color Index No. 10020), Food Black 1 (Color Index No. 28440), Food Green 3 (Color Index No. 42053), Acid Green 5 (Color Index No. 42095), Acid Blue 9 (Color Index). No.42090), Acid Blue 5(Color Index No.42052), Acid Green 3(Color Index No.42085), Acid Green 25(Color Index No.61570), Acid Brown 13(Color Index No.10410), Acid Red 52(Color Index No.45100), Acid Black 1(Color Index No.20470), Acid Red 18(Color Index No.16255), Acid Red 27(Color Index and Acid Violet 50 (Color Index No. 50325), more preferably Food Green 3 (Color Index No. 42053), Acid Green 5 (Color Index No. 42095), Acid Blue 9 (Color Index No. 42090), Acid Blue 5 (Color Index No. 42052), Acid Green 6 (Color Index No. 60325), Acid Red 73 (Color Index No. 27290), Acid Blue 1 (Color Index No. 42045), Acid Blue 7 (Color Index No. 42080), Acid Green 9 (Color Index No. 42100), Acid Blue 104 (Color Index No. 42735), and Acid Violet 50 (Color Index No. 50325), and more preferably Food Green 3 (Color Index No. 42053), Acid Green 5 (Color Index No. 42095), Acid Blue 9 (Color Index No. 42090), Acid Blue 5 (Color Index No. 42052), Acid Green 3 (Color Index No.Acid Blue 3 (Color Index No. 42051), Acid Green 50 (Color Index No. 44090), and Acid Blue 1 (Color Index No. 42045), and even more preferably Acid Blue 9 and Acid Red 52; <9> A dye composition for regenerated collagen fibers.

[0118] <11> the content of the component (A) in all acid dyes in the dye composition is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and still more preferably 95% by mass or more and 100% by mass or less; <1> ~ <10> Any one of the above dye compositions for regenerated collagen fibers. <12> The content of component (A) in the dye composition is preferably 0.001% by mass or more and 3.0% by mass or less, more preferably 0.002% by mass or more and 3.0% by mass or less, even more preferably 0.005% by mass or more and 1.0% by mass or less, still more preferably 0.01% by mass or more and 0.8% by mass or less, still more preferably 0.02% by mass or more and 0.6% by mass or less, still more preferably 0.03% by mass or more and 0.5% by mass or less, and still more preferably 0.05% by mass or more and 0.2% by mass or less, <1> ~ <11> Any one of the above dye compositions for regenerated collagen fibers. <13> The content of dyes other than acid dyes in the dye composition is preferably 0.1% by mass or less, more preferably 0.05% by mass or less, even more preferably 0.02% by mass or less, still more preferably 0.01% by mass or less, still more preferably 0.001% by mass or less, still more preferably 0.0001% by mass or less, and may be 0% by mass. <1> ~ <12> Any one of the above dye compositions for regenerated collagen fibers. <14> The content of water in the dye composition is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 85% by mass or more, and is preferably 99.999% by mass or less. <1> ~ <13> Any one of the above dye compositions for regenerated collagen fibers. <15> The pH of the dye composition is preferably 2.0 or more and 6 or less, more preferably 2.2 or more and 5 or less, and even more preferably 2.5 or more and 4 or less. <1> ~ <14> Any one of the above dye compositions for regenerated collagen fibers. <16> The dye composition is in the form of a liquid, paste, cream, gel, foam, spray, or wax, preferably a liquid. <1> ~ <15> Any one of the above dye compositions for regenerated collagen fibers. <17> The component (B1) contains one or more selected from the group consisting of benzoic acid, sodium benzoate, and potassium benzoate, and preferably contains one or more selected from the group consisting of benzoic acid and sodium benzoate. <1> ~ <16> Any one of the above dye compositions for regenerated collagen fibers. <18> the component (B2) 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> ~ <17> Any one of the above dye compositions for regenerated collagen fibers. <19> In the component (B2), 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> ~ <18> Any one of the above dye compositions for regenerated collagen fibers. <20> The acid value of the component (B2) 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> ~ <19> Any one of the above dye compositions for regenerated collagen fibers.

[0119] <21> The weight average molecular weight of the component (B2) 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> ~ <20> Any one of the above dye compositions for regenerated collagen fibers. <22> The component (B) preferably contains the component (B2), more preferably contains a styrene-maleic acid copolymer. <1> ~ <21> Any one of the above dye compositions for regenerated collagen fibers. <23> 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> ~ <22> Any one of the above dye compositions for regenerated collagen fibers. <24> The modified regenerated collagen fibers further contain a polyvalent metal, a salt thereof, or a complex thereof as component (C). <1> ~ <23> Any one of the above dye compositions for regenerated collagen fibers. <25> 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; <24> A dye composition for regenerated collagen fibers. <26> 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. <24> or <25> A dye composition for regenerated collagen fibers. <27> A method for dyeing regenerated collagen fibers, comprising: The dyeing method includes a step of applying a dye composition for regenerated collagen fibers to the regenerated collagen fibers, The dye composition contains the following component (A) and water, A method for dyeing regenerated collagen fibers, wherein the regenerated collagen fibers include modified regenerated collagen fibers containing the following component (B): (A) An acid dye having a sulfonic acid group and satisfying at least one of the following conditions (1) and (2): (1) Molecular weight of 500 or more (2) When the molecular weight is Mw, the difference (ab) between the number of sulfonic acid groups (a) and the number of cationic sites (b) divided by Mw [(ab) / Mw] is 0.0045 or less. (B) One or more compounds selected from the group consisting of the following components (B1) and (B2): (B1) Benzoic acid or its salts (B2) 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. <28> The method for applying the dye 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 applying the dye composition to regenerated collagen fibers in a dry state, or a method of immersing regenerated collagen fibers in a dry state in the dye composition. <27> Dyeing method. <29> The amount of the dye composition applied to the regenerated collagen fibers is preferably 1:0.2 to 1:500 in terms of bath ratio (dry mass of regenerated collagen fibers:mass of dye composition), 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. <27> or <28> Dyeing method. <30> When the dye composition is applied to the regenerated collagen fibers, the amount of the dye composition applied to the regenerated collagen fibers, 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, is preferably 1:0.2 to 1:200 in terms of the bath ratio (dry mass of regenerated collagen fibers:mass of dye composition), even more preferably 1:0.2 to 1:100, still more preferably 1:0.2 to 1:50, still more preferably 1:0.2 to 1:20, more preferably 1:0.5 to 1:10, still more preferably 1:0.5 to 1:5, and still more preferably 1:0.8 to 1:3. <29> Dyeing method.

[0120] <31> When regenerated collagen fibers are immersed in the dye composition, the bath ratio (dry mass of regenerated collagen fibers:mass of dye composition) is more preferably 1:2 to 1:500, even more preferably 1:3 to 1:250, still more preferably 1:5 to 1:100, still more preferably 1:10 to 1:50, and still more preferably 1:10 to 1:20, 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. <29> Dyeing method. <32> When the dye 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. <28> ~ <31> Either one of the staining methods. <33> After applying the dye 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. <28> ~ <30> , <32> Either one of the staining methods. <34> When the regenerated collagen fibers are immersed in the dye 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 1 hour or less. <28> , <29> , <31> Either one of the staining methods. <35> The temperature when the dye composition is applied to the regenerated collagen fibers is preferably 5°C or higher and 40°C or lower, more preferably 10°C or higher and 35°C or lower. <27> ~ <34> Either one of the staining methods. <36> a step of applying the dye composition to the regenerated collagen fibers and then rinsing the dye composition applied to the regenerated collagen fibers; <27> ~ <35> Either one of the staining methods. <37> a step of drying the regenerated collagen fibers after applying the dye composition to the regenerated collagen fibers, and after performing a rinsing step, if any; <27> ~ <36> Either one of the staining methods. <38> A colored modified regenerated collagen fiber containing the following components (A) and (B): (A) An acid dye having a sulfonic acid group and satisfying at least one of the following conditions (1) and (2): (1) Molecular weight of 500 or more (2) When the molecular weight is Mw, the difference (ab) between the number of sulfonic acid groups (a) and the number of cationic sites (b) divided by Mw [(ab) / Mw] is 0.0045 or less. (B) One or more compounds selected from the group consisting of the following components (B1) and (B2): (B1) Benzoic acid or its salts (B2) 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. <39> The colored modified regenerated collagen fiber further contains the component (C): a polyvalent metal, a salt thereof, or a complex thereof. <38> Colored modified regenerated collagen fiber. <40> <38> or <39> A fiber for headwear products, comprising colored modified regenerated collagen fiber.

[0121] <41> <38> or <39> A headwear product comprising colored modified regenerated collagen fibers. <42> The headwear product is a hair wig, a hairpiece, a weaving, a hair extension, a braided hair, a hair accessory, or a doll hair. <39> Fibers for head accessories, or <40> Head ornament products.

[0122] <43> A dye composition for regenerated collagen fibers, comprising: The dye composition contains the following component (A) and water, A dye composition for regenerated collagen fibers, wherein the regenerated collagen fibers comprise modified regenerated collagen fibers containing the following component (B): (A) Acid Black 52 (Color Index No.15711), Acid Green 1 (Color Index No.10020), Food Black 1 (Color Index No.28440), Food Green 3 (Color Index No.42053), Acid Green 5 (Color Index No.42095), Acid Blue 9 (Color Index No.42090), Acid Blue 5 (Color Index No.42052), Acid Green 3 (Color Index No.42085), Acid Green 25 (Color Index No.61570), Acid Brown 13 (Color Index No.10410), Acid Red 52 (Color Index No.45100), Acid Black 1 (Color Index No.20470), Acid Red 18 (Color Index No.16255), Acid Red 27(Color Index one or more acid dyes selected from the group consisting of Acid Blue 3 (Color Index No. 16185), Acid Green 50 (Color Index No. 44090), Acid Red 73 (Color Index No. 27290), Acid Blue 1 (Color Index No. 42045), Acid Orange 7 (Color Index No. 15510), Acid Red 249 (Color Index No. 18134), Acid Red 131 (no Color Index No.), and Acid Red 337 (Color Index No. 17102). (B) One or more compounds selected from the group consisting of the following components (B1) and (B2): (B1) Benzoic acid or its salts (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 3,000 or more and 15,000 or less.

[0123] <44> A method for dyeing regenerated collagen fibers, comprising: The dyeing method includes a step of applying a dye composition for regenerated collagen fibers to the regenerated collagen fibers, The dye composition contains the following component (A) and water, A method for dyeing regenerated collagen fibers, wherein the regenerated collagen fibers include modified regenerated collagen fibers containing the following component (B): (A) Acid Black 52 (Color Index No.15711), Acid Green 1 (Color Index No.10020), Food Black 1 (Color Index No.28440), Food Green 3 (Color Index No.42053), Acid Green 5 (Color Index No.42095), Acid Blue 9 (Color Index No.42090), Acid Blue 5 (Color Index No.42052), Acid Green 3 (Color Index No.42085), Acid Green 25 (Color Index No.61570), Acid Brown 13 (Color Index No.10410), Acid Red 52 (Color Index No.45100), Acid Black 1 (Color Index No.20470), Acid Red 18 (Color Index No.16255), Acid Red 27(Color Index one or more acid dyes selected from the group consisting of Acid Blue 3 (Color Index No. 16185), Acid Green 50 (Color Index No. 44090), Acid Red 73 (Color Index No. 27290), Acid Blue 1 (Color Index No. 42045), Acid Orange 7 (Color Index No. 15510), Acid Red 249 (Color Index No. 18134), Acid Red 131 (no Color Index No.), and Acid Red 337 (Color Index No. 17102). (B) One or more compounds selected from the group consisting of the following components (B1) and (B2): (B1) Benzoic acid or its salts (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 3,000 or more and 15,000 or less.

[0124] <45> A colored modified regenerated collagen fiber containing the following component (A) and component (B): A colored modified regenerated collagen fiber obtained by dyeing a modified regenerated collagen fiber containing component (B) with a dye composition containing component (A). (A) Acid Black 52 (Color Index No.15711), Acid Green 1 (Color Index No.10020), Food Black 1 (Color Index No.28440), Food Green 3 (Color Index No.42053), Acid Green 5 (Color Index No.42095), Acid Blue 9 (Color Index No.42090), Acid Blue 5 (Color Index No.42052), Acid Green 3 (Color Index No.42085), Acid Green 25 (Color Index No.61570), Acid Brown 13 (Color Index No.10410), Acid Red 52 (Color Index No.45100), Acid Black 1 (Color Index No.20470), Acid Red 18 (Color Index No.16255), Acid Red 27(Color Index one or more acid dyes selected from the group consisting of Acid Blue 3 (Color Index No. 16185), Acid Green 50 (Color Index No. 44090), Acid Red 73 (Color Index No. 27290), Acid Blue 1 (Color Index No. 42045), Acid Orange 7 (Color Index No. 15510), Acid Red 249 (Color Index No. 18134), Acid Red 131 (no Color Index No.), and Acid Red 337 (Color Index No. 17102). (B) One or more compounds selected from the group consisting of the following components (B1) and (B2): (B1) Benzoic acid or its salts (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 3,000 or more and 15,000 or less.

[0125] <46> Component (A) comprises one or more selected from the group consisting of Food Green 3 (Color Index No. 42053), Acid Green 5 (Color Index No. 42095), Acid Blue 9 (Color Index No. 42090), Acid Blue 5 (Color Index No. 42052), Acid Green 3 (Color Index No. 42085), Acid Red 52 (Color Index No. 45100), Acid Blue 3 (Color Index No. 42051), Acid Green 50 (Color Index No. 44090), and Acid Blue 1 (Color Index No. 42045), Acid Blue 7 (Color Index No. 42080), Acid Green 9 (Color Index No. 42100), Acid Blue 104 (Color Index No. 42735), and Acid Violet 50 (Color Index No. 50325); <43> A dye composition comprising the compound <44> or <45> Colored modified regenerated collagen fiber. <47> The content of component (A) in the dye composition is 0.03% by mass or more and 0.1% by mass or less. <43> or <46> A dye composition comprising the compound <44> or <46> or <45> or <46> Colored modified regenerated collagen fiber.

[0126] <48> The component (B2) contains 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, <43> , <46> and <47> any one of the dye compositions <44> , <46> and <47> Any one of the staining methods, or <45> ~ <47> Any one of the colored modified regenerated collagen fibers. <49> The modified regenerated collagen fiber contains, as component (B2), 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. <43> and <46> ~ <48> any one of the dye compositions <44> and <46> ~ <48> Any one of the staining methods, or <45> ~ <48> Any one of the colored modified regenerated collagen fibers. <50> Component (B) contains component (B2), <43> and <46> ~ <49> any one of the dye compositions <44> and <46> ~ <49> Any one of the staining methods, or <45> ~ <49> Any one of the colored modified regenerated collagen fibers. <51> The content of compound (B) in the modified regenerated collagen fiber is 20% by mass or more and 40% by mass or less. <43> and <46> ~ <50> any one of the dye compositions <44> and <46> ~ <50> Any one of the staining methods, or <45> ~ <50> Any one of the colored modified regenerated collagen fibers.

[0127] <52> The modified regenerated collagen fibers contain aluminum or a salt or complex thereof as component (C). <43> and <46> ~ <51> any one of the dye compositions <44> and <46> ~ <51> Any one of the staining methods, or <45> ~ <51> Any one of the colored modified regenerated collagen fibers. <53> The content of component (C) in the modified regenerated collagen fiber is 2.0% by mass or more and 10% by mass or less in terms of the amount of metal elements. <52> A dye composition comprising the compound <52> or <52> Colored modified regenerated collagen fiber.

[0128] <54> When the dye composition is a coating type, the mass ratio [(B) / (A)] of the component (B) in the fiber for headwear to the component (A) in the dye composition is 200 or more and 400 or less. <43> and <46> ~ <53> Any one of the dye compositions. <55> When the dye composition is a dip-type dye, the mass ratio [(B) / (A)] of the component (B) in the fiber for headwear to the component (A) in the dye composition is 10 or more and 60 or less. <43> and <46> ~ <53> Any one of the dye compositions. <56> When the dye composition is a coating type, the mass ratio [(C) / (A)] of the component (C) in the fiber for headwear to the component (A) in the dye composition is 25 or more and 100 or less. <43> and <52> ~ <54> Any one of the dye compositions. <57> When the dye composition is a dip-type dye, the mass ratio [(C) / (A)] of the component (C) in the fiber for headwear to the component (A) in the dye composition is 3 or more and 12 or less. <43> , <52> ~ <53> and <55> Any one of the dye compositions.

[0129] <58> When applied by coating, the mass ratio [(B) / (A)] of the component (B) in the fiber for headwear products to the component (A) in the dye composition is 200 or more and 400 or less. <44> and <46> ~ <53> Either one of the staining methods. <59> When applied by immersion, the mass ratio [(B) / (A)] of the component (B) in the fiber for headwear products to the component (A) in the dye composition is 10 or more and 60 or less. <44> and <46> ~ <53> Either one of the staining methods. <60> When applied by coating, the mass ratio [(C) / (A)] of the component (C) in the fiber for headwear products to the component (A) in the dye composition is 25 or more and 100 or less. <52> ~ <53> and <58> Either one of the staining methods. <61> When applied by immersion, the mass ratio [(C) / (A)] of the component (C) in the fiber for headwear products to the component (A) in the dye composition is 3 or more and 12 or less. <52> ~ <53> and <59> Either one of the staining methods.

[0130] <62> When it is colored by coating, the mass ratio [(B) / (A)] of component (B) in the fiber for the headdress product and component (A) in the dye composition is 200 or more and 400 or less, and it is any one of <45> to <53> of the colored and modified regenerated collagen fiber. <63> When it is colored by immersion, the mass ratio [(B) / (A)] of component (B) in the fiber for the headdress product and component (A) in the dye composition is 10 or more and 60 or less, and it is any one of <45> to <53> of the colored and modified regenerated collagen fiber. <64> When it is colored by coating, the mass ratio [(C) / (A)] of component (C) in the fiber for the headdress product and component (A) in the dye composition is 25 or more and 100 or less, and it is any one of <52> to <53> and <62> of the colored and modified regenerated collagen fiber. <65> When it is colored by immersion, the mass ratio [(C) / (A)] of component (C) in the fiber for the headdress product and component (A) in the dye composition is 3 or more and 12 or less, and it is any one of <52> to <53> and <63> of the colored and modified regenerated collagen fiber.

[0131] <66> A headdress product containing any one of <45> to <53> and <62> to <65> of the colored and modified regenerated collagen fiber.

Example

[0132] 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 carried out by the following methods.

[0133] <pH measurement> Using a pH meter (F-72, manufactured by Horiba, Ltd.), the pH at 25 °C was measured.

[0134] <Quantification of benzoic acid in the modified regenerated collagen fiber> In this specification, the amount of benzoic acid contained in the modified regenerated collagen fiber B1 obtained in Production Example 2 was determined by the following method. ·reagent 6N Hydrochloric acid: Titrant for volumetric analysis, manufactured by Kanto Chemical Co., Ltd. Sodium acetate: Special grade, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Acetic acid: Special grade, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Acetonitrile: LC / MS grade, manufactured by Kanto Chemical Co., Ltd. Sodium benzoate: Special grade, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Ultrapure water: Milli-Q ultrapure water production system, manufactured by Millipore ·Quantitative method The sample (modified regenerated collagen fiber B1) was conditioned at 20°C and 65% relative humidity for 24 hours, then finely chopped. Approximately 10 mg of the fiber was precisely weighed, and 3 mL of 6N hydrochloric acid was added. The fiber was then heated and dissolved at 50°C for 15 hours. After cooling, the fiber was filtered to prepare the sample solution. Separately, sodium benzoate was dissolved in the mobile phase to prepare a benzoic acid concentration of 0.1 to 100 μg / mL. This was used as the standard solution for constructing the calibration curve. Liquid chromatography (HPLC) measurements were performed using the sample solution and the standard solution, and the amount of benzoic acid was calculated from the ratio of the peak area of ​​the sample solution to that of the standard solution. Measurement conditions Detector: UV-visible spectrophotometer Measurement wavelength: 230nm Column: A stainless steel tube having an inner diameter of 21 mm and a length of 150 mm was packed with 5 μm octadecylsilanized silica gel for liquid chromatography. Column temperature: constant temperature around 40°C Mobile phase: Approximately 0.68 g of sodium acetate and 0.91 g of acetic acid were dissolved in 750 mL of ultrapure water, and then 250 mL of acetonitrile was added and mixed. ·HPLC / UV conditions Device: UltiMate 3000 system (Thermo Fisher Scientific) Column: L column 2 ODS 5 μm 2.1 × 150 mm (Chemicals Evaluation and Research Institute, Japan) Column temperature: 40℃ Mobile phase: 20 mM ammonium acetate, 25% acetonitrile buffer Analysis time: 10 minutes Detector: DAD (Diode Array Detector) Detection wavelength: 230 nm Flow rate: 0.3 mL / min (isocratic elution) Injection volume: 10μL

[0135] <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 was calculated in terms of polystyrene. (1) Reagents 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 pretreatment method Approximately 50 mg of sample was precisely weighed, 0.5 mL of ultrapure water was added, and 10 mL of the mobile phase described below was added to dissolve the solution, which was then filtered to prepare a sample solution. (3) Measurement Using the sample solution and the standard solution, gel permeation chromatography (GPC) measurement was carried out under the following conditions to determine the weight average molecular weight in terms of polystyrene. ·Flow rate: 1mL / min Mobile phase: 60 mM phosphoric acid, 50 mM LiBr in DMF Column: TSKgel α (Alpha) column (Tosoh Corporation) Detector: RI (Differential Refractive Index Detector)

[0136] <Quantitative determination of styrene-maleic acid copolymer in modified regenerated collagen fibers> In this specification, the amount of styrene-maleic acid copolymer in the modified regenerated collagen fiber B2 obtained in Production Example 3 was determined 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.

[0137] <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 that, several drops of sulfuric acid were added, and the mixture was heated again until no more white smoke was emitted. It was then 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

[0138] 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 at 20°C and 65% relative humidity for 24 hours. A 5% aqueous solution of sodium hydroxide was then added in portions over approximately 1 to 5 hours to adjust the final pH of the solution to 4.5 to 5.0 after 5 hours. The fibers were then left in the solution for another 3 hours and thoroughly washed with water to obtain regenerated collagen fibers C0.

[0139] 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 and comparative example. (Step 2) Component (B1), benzoic acid (Wako Special Grade Reagent, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., molecular weight: 122), was dissolved in water, and the pH was adjusted to 6.0 with a pH adjuster (sodium hydroxide) to prepare a fiber treatment agent containing 25.4% by mass of benzoic acid. The fiber bundles were immersed in a volume of fiber treatment agent such that the bath ratio (mass of fiber bundle after drying in step 1: mass of fiber treatment 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 3 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 flow of the fibers was adjusted with a comb. (Step 6) Each fiber bundle was hung in a dryer set at 60°C, and a 250g 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 7) The fiber bundle was removed from the dryer, allowed to cool to room temperature, and the weight was removed.

[0140] The content of benzoic acid in the modified regenerated collagen fiber B1 produced in Production Example 2 above was 27.3 mass % as benzoic acid, and the content of aluminum was 5.7 mass %.

[0141] Production Example 3 (Production of Modified Regenerated Collagen Fiber B2) The regenerated collagen fiber C0 obtained in Production Example 1 was treated according to the following procedure to obtain modified regenerated collagen fiber B2. (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 B2a agent shown in Table 2, the following (Procedure 2) to (Procedure 5) were carried out. Agents B2a and B2b shown in Table 2 were prepared by blending and mixing the components listed in Table 2 using styrene-maleic acid copolymer (XIRAN1000HNa, manufactured by Polyscope, weight average molecular weight (Mw): 9195, acid value: 475 mgKOH / g, styrene / maleic acid molar ratio: 1 / 1) as component (B2). (Step 2) The fiber bundles prepared in (Procedure 1) were immersed in an amount of B2a agent such that the bath ratio (mass of fiber bundle after drying in Procedure 1: mass of B2a 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 B2b shown in Table 2 instead of the agent B2a. 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.

[0142] [Table 2] The blending amounts (mass %) shown in Table 2 are all amounts of active ingredients. The modified regenerated collagen fiber B2 produced in Production Example 3 above had a styrene-maleic acid copolymer content of 31.4 mass % and an aluminum content of 5.5 mass %.

[0143] <Preparation of dye composition for regenerated collagen fibers> Examples 1 to 7, Comparative Example 1 The components shown in Table 3 were blended in the blending ratios shown in Table 3 and mixed until uniform. The pH was then adjusted to 3.0 using lactic acid or sodium hydroxide to prepare a dye composition for regenerated collagen fibers.

[0144] <Evaluation of dye composition for regenerated collagen fibers> Examples 8 to 15, Comparative Example 2 The dyeing properties and fastness of the obtained dye compositions were evaluated by the following methods. The results are shown in Table 3.

[0145] <Dyeability (color difference before and after dyeing ΔE * ab1)> (dying process) A fiber bundle having a length of 10 cm and a mass of 1 g was prepared using the modified regenerated collagen fibers shown in Table 3. The fiber bundle was washed with plain shampoo having the following composition, then rinsed with warm water at 40°C, and thoroughly dried with a dryer. The color (L0 * ,a0 * ,b0 * ) was measured using a color difference meter (CR-400, Konica Minolta, Inc.). * ,a0 * ,b0 * The values ​​were measured at six points per fiber bundle and the average value was calculated. Next, the fiber bundle was immersed in a container in an amount of dye composition such that the bath ratio (calculated based on 1 g of dry fiber mass) shown in the table was obtained when the fiber mass after conditioning at 20°C and 65% relative humidity for 24 hours was taken as the dry mass, and the container was then sealed. The container was then placed in a dryer (SOFW-450SB, AS ONE Corporation) set to the temperature shown in the table. After leaving for 30 minutes, the fiber bundle was rinsed with 40°C warm water for 30 seconds to wash away the dye composition, and then the fiber bundle was lathered with a plain shampoo of the following composition for 15 seconds and then rinsed with 40°C warm water for 15 seconds, this operation being repeated twice. Next, a plain conditioner of the following composition was applied for 15 seconds, and the fiber bundle was rinsed with 40°C warm water for 15 seconds, and then thoroughly dried with cold air from a dryer. The dried fiber bundle (dyed fiber bundle) was measured for hue (L1) using a color difference meter in the same manner as above. * ,a1 * ,b1 * ) was measured. The color difference ΔE before and after dyeing of the fiber bundle is calculated using the following formula: * ab1 was calculated and shown in Table 3. ΔE * A larger ab1 value means higher staining.

[0146] ΔE * ab1=〔(L1 * -L0 * ) 2 +(a1 * -a0 * ) 2 +(b1 * -b0 * ) 2 〕 1 / 2

[0147] (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)

[0148] (Plain conditioner composition) Ingredients (mass %) Trimethylstearylammonium chloride (*1) 1.01 Distearyldimethylammonium chloride (*2) 2.0 Propylene glycol 5.0 Cetyl alcohol (*3) 2.0 Isopropyl alcohol 0.4 Methyl parahydroxybenzoate(*4) 0.1 Refined water residue Total 100.0 *1: 3.6% by mass of Kotamin 86W (manufactured by Kao Corporation, active ingredient 28% by mass) *2: 2.7% by mass of Kotamin D86P (manufactured by Kao Corporation, active ingredient 75% by mass) *3: Kalcol 6870 (Kao Corporation) *4: Mekkinsu M (manufactured by Ueno Pharmaceutical Co., Ltd.)

[0149] <Fastness (color difference ΔE before and after washing) * ab2)> The dyed fiber bundle obtained in the above-mentioned "dyeability" evaluation was used as the "fiber bundle before washing." The fiber bundle before washing was immersed in a container containing 15 g of a solution prepared by diluting the plain shampoo 10 times with purified water, and 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 to 40°C. The container was rotated at a rotation speed of 80 rpm, and heated and stirred for 90 minutes. The container containing the fiber bundle was removed from the dryer and returned to room temperature. The fiber bundle was then removed from the container, rinsed with running tap water at 40°C for 30 seconds, and thoroughly dried with cold air from a dryer. The dried fiber bundle (fiber bundle after washing) was measured for hue (L2 * ,a2 * ,b2 * ) was measured. The color difference ΔE before and after cleaning of the fiber bundle is calculated using the following formula: * ab2 was calculated and shown in Table 3. ΔE * The smaller the ab value, the higher the robustness.

[0150] ΔE * ab2=〔(L1 * -L2 * ) 2 +(a1 * -a2 * ) 2 +(b1 * -b2 * ) 2 〕 1 / 2 The blending amounts (mass %) shown in Table 3 are all amounts of active ingredients.

[0151] [Table 3]

[0152] Table 3 shows that the dye composition of the present invention has better dye fastness to the specified modified regenerated collagen fibers than the dye composition of Comparative Example 1, which uses an acid dye that does not fall under component (A).

[0153] 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 3 to obtain modified regenerated collagen fiber B3. Next, the modified regenerated collagen fiber B3 is treated in the same manner as above using the dye composition shown in Table 3, following the procedure shown under <Dyeability>.

[0154] The effects of the present invention can be achieved even when the stain composition of Formulation Example 2 shown in Table 4 or the stain compositions of Formulation Examples 3 to 8 shown in Table 5 is used.

[0155] [Table 4]

[0156] [Table 5] [Industrial Applicability]

[0157] According to the present invention, a dye composition for regenerated collagen fibers that uses a dye and has excellent fastness after dyeing can be provided.< / ph>

Claims

1. A dye composition for regenerated collagen fibers, comprising: The dye composition contains the following component (A) and water, A dye composition for regenerated collagen fibers, wherein the regenerated collagen fibers comprise modified regenerated collagen fibers containing the following component (B): (A) An acid dye having a sulfonic acid group and satisfying at least one of the following (1) and (2): (1) Molecular weight of 500 or more (2) When the molecular weight is Mw, the difference (a-b) between the number of sulfonic acid groups (a) and the number of cationic sites (b) divided by Mw [(a-b) / Mw] is 0.0045 or less. (B) One or more compounds selected from the group consisting of the following components (B1) and (B2): (B1) Benzoic acid or its salt (B2) 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. The component (A) is Acid Black 52 (Color Index No.15711), Acid Green 1 (Color Index No.10020), Food Black 1 (Color Index No.28440), Food Green 3 (Color Index No.42053), Acid Green 5 (Color Index No.42095), Acid Blue 9 (Color Index No.42090), Acid Blue 5 (Color Index No.42052), Acid Green 3 (Color Index No.42085), Acid Green 25 (Color Index No.61570), Acid Brown 13 (Color Index No.10410), Acid Red 52 (Color Index No.45100), Acid Black 1 (Color Index No.20470), Acid Red 18 (Color Index No.16255), Acid Red 27 (Color Index No.16185), Acid Blue 3 (Color Index No.42051), Acid Green 50 (Color Index No.44090), Acid Red 73 (Color Index No.27290), Acid Blue 1 (Color Index No.42045), Acid Red 184 (Color Index No.15685), Acid Red 35 (Color Index No.18065), Acid Red 14 (Color Index No.14720), Food Red 6 (Color Index No.16155), Acid Orange 3 (Color Index No.10385), Acid Orange 24 (Color Index No.20170), Acid Violet 43 (Color Index No.60730), Acid Blue 62 (Color Index No.62045), Acid Red 88 (Color Index No.15620), Acid Yellow 11 (Color Index No.18820)、Acid Yellow 36(Color Index No.13065)、Acid Yellow 1(Color Index No.10316)、Acid Orange 7(Color Index No.15510)、Acid Orange 20(Color Index No.14600)、Acid Orange 6(Color Index No.14270)、Food Red 17(Color Index No.16035)、Acid Red 41(Color Index No.16290)、Acid Red 1(Color Index No.18050)、Acid Red 155(Color Index No.18130)、Acid Red 180(Color Index No.18736)、Acid Yellow 17(Color Index No.18965)、Acid Yellow 23(Color Index No.19140)、Acid Red 163(Color Index No.24790)、Food Black 2(Color Index No.27755)、Direct Orange 39(Color Index No.40215)、Acid Blue 7(Color Index No.42080)、Acid Green 9(Color Index No.42100)、Acid Green 22(Color Index No.42170)、Acid Blue 104(Color Index No.42735)、Acid Violet 9(Color Index No.45190)、Acid Red 50(Color Index No.45220)、Acid Violet 50(Color Index No.50325)、Acid Black 2(Color Index No.50420)、Acid Blue 80(Color Index No.61585)、Acid Blue 87(Color Index No.74180)、Acid Red 195(Color Index No.18760)、Acid Red 249(Color Index No.18134), Acid Red 131, and Acid Red 337 (Color Index No. 17102).

3. The component (A) is Acid Black 52 (Color Index No. 15711), Acid Green 1 (Color Index No. 10020), Food Black 1 (Color Index No. 28440), Food Green 3 (Color Index No. 42053), Acid Green 5 (Color Index No. 42095), Acid Blue 9 (Color Index). No.42090), Acid Blue 5 (Color Index No.42052), Acid Green 3 (Color Index No.42085), Acid Green 25 (Color Index No.61570), Acid Brown 13 (Color Index No.10410), Acid Red 52 (Color Index No.45100), Acid Black 1 (Color Index No.20470), Acid Red 18 (Color Index No.16255), Acid Red 27 (Color Index No.16185), Acid Blue 3 (Color Index 3. The dye composition for regenerated collagen fibers according to claim 2, comprising one or more dyes selected from the group consisting of Acid Green 50 (Color Index No. 42051), Acid Green 50 (Color Index No. 44090), Acid Red 73 (Color Index No. 27290), Acid Blue 1 (Color Index No. 42045), Acid Orange 7 (Color Index No. 15510), Acid Red 249 (Color Index No. 18134), Acid Red 131 (no Color Index No.), and Acid Red 337 (Color Index No. 17102).

4. The dye composition for regenerated collagen fibers according to claim 1 , wherein the number of cationic sites (b) is 1 or more.

5. 5. The dye composition for regenerated collagen fibers according to claim 4, wherein the component (A) comprises one or more dyes selected from the group consisting of Food Green 3 (Color Index No. 42053), Acid Green 5 (Color Index No. 42095), Acid Blue 9 (Color Index No. 42090), Acid Blue 5 (Color Index No. 42052), Acid Green 3 (Color Index No. 42085), Acid Red 52 (Color Index No. 45100), Acid Blue 3 (Color Index No. 42051), Acid Green 50 (Color Index No. 44090), and Acid Blue 1 (Color Index No. 42045), Acid Blue 7 (Color Index No. 42080), Acid Green 9 (Color Index No. 42100), Acid Blue 104 (Color Index No. 42735), and Acid Violet 50 (Color Index No. 50325).

6. 2. The dye composition for regenerated collagen fibers according to claim 1, wherein the content of said component (A) in said dye composition is 0.001% by mass or more and 3.0% by mass or less.

7. The dye composition for regenerated collagen fibers according to claim 1 , wherein the component (B) comprises a component (B2).

8. The dye composition for regenerated collagen fibers according to any one of claims 1 to 7, wherein the component (B2) comprises a styrene-maleic acid copolymer.

9. A method for dyeing regenerated collagen fibers, comprising: The dyeing method includes a step of applying a dye composition for regenerated collagen fibers to the regenerated collagen fibers, The dye composition contains the following component (A) and water, A method for dyeing regenerated collagen fibers, wherein the regenerated collagen fibers include modified regenerated collagen fibers containing the following component (B): (A) An acid dye having a sulfonic acid group and satisfying at least one of the following (1) and (2): (1) Molecular weight of 500 or more (2) When the molecular weight is Mw, the difference (a-b) between the number of sulfonic acid groups (a) and the number of cationic sites (b) divided by Mw [(a-b) / Mw] is 0.0045 or less. (B) One or more compounds selected from the group consisting of the following components (B1) and (B2): (B1) Benzoic acid or its salt (B2) 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.

10. A colored modified regenerated collagen fiber containing the following components (A) and (B): (A) An acid dye having a sulfonic acid group and satisfying at least one of the following (1) and (2): (1) Molecular weight of 500 or more (2) When the molecular weight is Mw, the difference (a-b) between the number of sulfonic acid groups (a) and the number of cationic sites (b) divided by Mw [(a-b) / Mw] is 0.0045 or less. (B) One or more compounds selected from the group consisting of the following components (B1) and (B2): (B1) Benzoic acid or its salt (B2) 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.

11. A headwear product comprising the colored modified regenerated collagen fiber according to claim 10.

Images