Functionality-imparting composition

Abstract

Provided are a novel functionality-imparting composition and method for imparting functionality that make it possible to impart a functionality that imparts durability against washing to a target such as natural fibers.　The present invention provides a photothermal heating performance–imparting composition, an antimicrobial performance–imparting composition, a deodorant performance–imparting composition, or an antistatic performance–imparting composition that contains a melanin precursor.

Description

Functionality-imparting composition

[0001] The present invention relates to a composition for imparting functionality (photoheating performance, antibacterial performance, deodorizing performance, or antistatic performance), a method for imparting functionality, a method for producing functional fibers, and a method for producing photoheating leather.

[0002] In the clothing industry, the market for clothing with various functionalities, such as antibacterial, deodorizing, quick-drying, heat-retaining, shape-stable, UV protection, antistatic (antistatic), and conductive properties, is expanding. In particular, due to increasing consumer awareness of hygiene and cleanliness, there is a high demand for antibacterial products and deodorizing products that eliminate unpleasant odors such as sweat odor, tobacco odor, and body odor. Furthermore, for winter clothing, products with a warming function and an antistatic function that reduces static electricity-induced dust adhesion and clinging to clothing, thereby increasing comfort, are preferred. For example, proposed antibacterial fibers include synthetic or natural fibers that contain natural or organic synthetic antibacterial components, such as metal ions or tea catechins; deodorizing fibers that incorporate ceramic particles, metal ions, or other substances with adsorption or chemical decomposition properties for odor components; and antistatic fibers that incorporate hydrophilic polymers, highly conductive carbon fibers, conductive ceramic particles, or other fine particles. Common products of thermal functional fibers include fibers that absorb moisture and generate heat when sweating, as well as chemical fibers with ceramic particles kneaded into the core that have photothermal properties that convert light into heat. There is also a report of a wool fabric with photothermal properties being produced by adsorbing vanadium ions with photothermal properties onto wool (Patent Document 1).

[0003] On the other hand, melanin is a yellow to black pigment formed in animals and plants, and is known to have ultraviolet absorbing functions, radical scavenging functions, antioxidant functions, etc. Because melanin is a highly safe substance derived from living organisms, it is widely used as an ultraviolet absorber, antioxidant, pigment, etc. in cosmetics, foods, plastic products, etc.

[0004] In vivo, melanin is biosynthesized by the oxidation of the substrate compound tyrosine, catalytically catalyzed by the melanin-producing enzyme tyrosinase, to produce dihydroxyindoles (e.g., 5,6-dihydroxyindole, 5,6-dihydroxyindole-2-carboxylic acid) via dopa and dopaquinone, followed by polymerization of these dihydroxyindoles. When using melanin as a dye, it is difficult to penetrate and dye an object using melanin, a high-molecular-weight compound, directly. Therefore, melanin precursors, such as dihydroxyindoles, are used as dyes to form melanin within the object. For example, a method for dyeing cotton fibers or human gray hair using a dye solution containing 5,6-dihydroxyindole (Patent Document 2) and a method for dyeing fibers with an aqueous solution containing tyrosinase and tyrosine (Patent Document 3) have been reported. According to Patent Documents 2 and 3, cotton fibers and the like dyed black to dark brown can be obtained, but the function of melanin within fibers is completely unknown.

[0005] (Patent Document 1) JP 2021-42480 A (Patent Document 2) JP 2011-46658 A (Patent Document 3) JP 9-87977 A

[0006] The present invention relates to the following 1) to 16). 1) A composition for imparting photoheating performance, containing a melanin precursor. 2) A composition for imparting antibacterial performance, containing a melanin precursor. 3) A composition for imparting deodorizing performance, containing a melanin precursor. 4) A composition for imparting antistatic performance, containing a melanin precursor. 5) A method for imparting photoheating performance to an object, comprising applying a composition containing a melanin precursor to the object. 6) A method for imparting antibacterial performance to an object, comprising applying a composition containing a melanin precursor to the object. 7) A method for imparting deodorizing performance to an object, comprising applying a composition containing a melanin precursor to the object. 8) A method for imparting antistatic performance to an object, comprising applying a composition containing a melanin precursor to the object. 9) A method for producing fibers or leather imparted with photoheating performance, comprising applying a composition containing a melanin precursor to the fiber or leather. 10) A method for producing fibers imparted with antibacterial performance, comprising applying a composition containing a melanin precursor to the fiber. 11) A method for producing fibers imparted with deodorizing performance, comprising applying a composition containing a melanin precursor to the fiber. 12) A method for producing fibers imparted with antistatic properties, comprising applying a composition containing a melanin precursor to the fibers. 13) Use of a composition containing a melanin precursor as a composition for imparting photoheating properties. 14) Use of a composition containing a melanin precursor as a composition for imparting antibacterial properties. 15) Use of a composition containing a melanin precursor as a composition for imparting deodorizing properties. 16) Use of a composition containing a melanin precursor as a composition for imparting antistatic properties. Detailed Description of the Invention

[0007] Functional clothing made from natural fibers is in demand for consumers with sensitive skin and other sensitive skin. However, when functional particles are used to impart functionality such as photothermal performance to natural fibers, coating the functional particles with a binder is considered, but this is impractical in terms of the durability and texture of the fibers. Furthermore, natural fibers are prone to losing their functionality when washed with laundry detergent. Therefore, the present invention relates to providing a novel composition for imparting functionality and a method for imparting functionality that can impart washfastness to target objects such as natural fibers.

[0008] The present inventors have discovered that by using a melanin precursor to generate melanin inside an object, it is possible to impart photothermal performance, antibacterial performance, deodorizing performance, and antistatic performance to the object, and that the imparted photothermal performance, antibacterial performance, deodorizing performance, and antistatic performance are highly durable against washing.

[0009] According to the present invention, it is possible to impart photothermal performance, antibacterial performance, deodorizing performance or antistatic performance to objects such as textiles and leather, while also providing fastness to washing.

[0010] In this specification, the photoheat generating performance, antibacterial performance, deodorizing performance, and antistatic performance may be collectively referred to as "functionality."

[0011] (Functionality-imparting composition) The functionality-imparting composition of the present invention contains a melanin precursor. The melanin precursor is a compound that is polymerized by air oxidation and converted to melanin. In the present invention, examples of melanin precursors include tyrosine, dopa, dopaquinone, and dihydroxyindoles. One or a combination of two or more melanin precursors can be used. Among them, from the viewpoint of efficiently imparting photothermal performance, antibacterial performance, deodorizing performance, or antistatic performance, one or two or more selected from tyrosine and dihydroxyindoles are preferred, and one or two or more selected from dihydroxyindoles are more preferred. Examples of dihydroxyindoles include compounds represented by the following general formula (1) or salts thereof:

[0012]

[0013] (wherein the dashed line indicates the presence or absence of a π bond. R 1 represents a hydroxyl group or an acetoxy group. 2 represents a hydrogen atom or -COOR (wherein R is a hydrogen atom, a methyl group, or an ethyl group). 3 represents a hydrogen atom, an acetyl group, a methyl group, or an ethyl group.

[0014] From the viewpoint of ease of penetration into the target object, it is preferable that the dashed line portion in general formula (1) has a π bond. 1 is preferably a hydroxyl group, and R 2 is preferably a hydrogen atom or —COOR (R is a hydrogen atom, a methyl group, or an ethyl group), and more preferably a hydrogen atom or —COOH. 3 is preferably a hydrogen atom.

[0015] Examples of the compound represented by general formula (1) include 5,6-dihydroxyindole, 5,6-dihydroxyindole-2-carboxylic acid, methyl 5,6-dihydroxyindole-2-carboxylate, ethyl 5,6-dihydroxyindole-2-carboxylate, N-methyl-5,6-dihydroxyindole, N-methyl-5,6-dihydroxyindole-2-carboxylic acid, N-ethyl-5,6-dihydroxyindole, N-ethyl-5,6-dihydroxyindole-2-carboxylic acid, N-acetyl-5,6-dihydroxyindole, N-acetyl-5,6-dihydroxyindole-2-carboxylic acid, 5-acetoxy-6-hydroxyindole, 5-acetoxy-6-hydroxyindole-2- Examples of the salt of the compound represented by general formula (1) include carboxylic acid, 5,6-dihydroxyindoline, 5,6-dihydroxyindoline-2-carboxylic acid, methyl 5,6-dihydroxyindoline-2-carboxylate, ethyl 5,6-dihydroxyindoline-2-carboxylate, N-methyl-5,6-dihydroxyindoline, N-methyl-5,6-dihydroxyindoline-2-carboxylic acid, N-ethyl-5,6-dihydroxyindoline, N-ethyl-5,6-dihydroxyindoline-2-carboxylic acid, N-acetyl-5,6-dihydroxyindoline, N-acetyl-5,6-dihydroxyindoline-2-carboxylic acid, 5-acetoxy-6-hydroxyindoline, and 5-acetoxy-6-hydroxyindoline-2-carboxylic acid. Examples of the salt of the compound represented by general formula (1) include hydrochloride, hydrobromide, sulfate, phosphate, acetate, propionate, lactate, citrate, and the like of the compound, and among these, hydrobromide is preferred from the viewpoint of availability. In general formula (1), R 2 is —COOH, the salt of the compound represented by general formula (1) may be a carboxylate thereof (R 2 Ga-COO - X + (X + is Na + , K. + alkali metal ions such as Ca + , Mg + and cations such as ammonium ion).

[0016] From the viewpoint of ease of penetration into the target object, the compound represented by general formula (1) or a salt thereof is preferably one or more selected from the group consisting of 5,6-dihydroxyindole, 5,6-dihydroxyindole-2-carboxylic acid, 5,6-dihydroxyindoline, 5,6-dihydroxyindoline-2-carboxylic acid, and salts thereof, more preferably one or more selected from the group consisting of 5,6-dihydroxyindole, 5,6-dihydroxyindole-2-carboxylic acid, and 5,6-dihydroxyindoline hydrobromide, even more preferably one or two selected from the group consisting of 5,6-dihydroxyindole and 5,6-dihydroxyindole-2-carboxylic acid, and even more preferably a combination of 5,6-dihydroxyindole and 5,6-dihydroxyindole-2-carboxylic acid.

[0017] When 5,6-dihydroxyindole and 5,6-dihydroxyindole-2-carboxylic acid are used in combination, from the viewpoint of imparting higher photothermal performance, antibacterial performance, deodorizing performance, or antistatic performance, and from the viewpoint of efficiently imparting photothermal performance, antibacterial performance, deodorizing performance, or antistatic performance, the molar ratio thereof is preferably in the range of 50:50 to 99:1, more preferably in the range of 80:20 to 99:1, and even more preferably in the range of 85:15 to 95:5. The molar ratio of 5,6-dihydroxyindole to 5,6-dihydroxyindole-2-carboxylic acid can be quantified by reverse-phase HPLC.

[0018] The melanin precursor may be commercially available or may be obtained by a previously reported enzymatic or chemical method. For example, the enzymatic method described in Japanese Patent No. 4578221 and the chemical method described in Japanese Patent No. 7212628 may be used as references.

[0019] The content of the melanin precursor in the functionality-imparting composition of the present invention is preferably 2 mM or more, more preferably 4 mM or more, more preferably 5 mM or more, even more preferably 6 mM or more, and even more preferably 10 mM or more, from the viewpoint of imparting high photothermal performance, antibacterial performance, deodorizing performance, or antistatic performance. The upper limit is not particularly limited, but from the viewpoint of cost, it is preferably 120 mM or less, more preferably 67 mM or less, more preferably 60 mM or less, more preferably 50 mM or less, even more preferably 40 mM or less, and even more preferably 30 mM or less. The content of the melanin precursor in the functionality-imparting composition is preferably 2 mM or more and 120 mM or less, more preferably 2 mM or more and 67 mM or less, more preferably 4 mM or more and 67 mM or less, even more preferably 5 mM or more and 67 mM or less, even more preferably 6 mM or more and 60 mM or less, even more preferably 6 mM or more and 50 mM or less, even more preferably 6 mM or more and 40 mM or less, and even more preferably 10 mM or more and 30 mM or less.

[0020] From the viewpoint of solubilizing the melanin precursor, the functionality-imparting composition of the present invention preferably further contains a solvent. Examples of the solvent include water; lower alcohols such as ethanol and isopropyl alcohol; low-molecular-weight diols and triols having 6 or less carbon atoms such as ethylene glycol, propylene glycol, 1,3-butylene glycol, and glycerin; and buffer solutions such as phosphate buffer and acetate buffer. One or a combination of two or more solvents can be used. Among these, water, ethanol, or a mixture thereof is preferred from the viewpoint of cost. From the viewpoint of antiseptic properties, the ethanol concentration in the solvent is preferably 5% by mass or more, more preferably 10% by mass or more, and preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less.

[0021] The functionality-imparting composition of the present invention may further contain metal ions from the viewpoint of imparting high antibacterial, deodorizing, or antistatic properties. The metal ions are not particularly limited as long as they have antibacterial, deodorizing, or antistatic properties. For example, Ag + Ion, Na + Monovalent metal ions such as Hg 2+ions, Cu 2+ ions, Au 2+ ions, Ni 2+ ions, Pb 2+ ions, Zn 2+ ions, Ti 2+ ions, Fe 2+ Ion, Co 2+ divalent metal ions such as Al ions; 3+ ions, Fe 3+ These may be used alone or in combination of two or more. Among them, from the viewpoint of imparting higher antibacterial or deodorizing performance, Ag + ions, Cu 2+ ions, Zn 2+ ions, Fe 2+ From the viewpoint of imparting higher antistatic properties, Cu ions are preferred. 2+ ions, Ni 2+ ions, Zn 2+ ions, Fe 2+ Ion, Co 2+ Ions are preferred. As the metal ions, supported systems in which metal ions are supported on a carrier, metal compounds such as silver oxide, silver nitrate, copper sulfate, and iron sulfate, metal complexes, etc. Examples of carriers for supporting metal ions include silicate-based carriers such as zeolite, phosphate-based carriers such as calcium phosphate and zirconium phosphate, and glass-based carriers such as soluble glass.

[0022] The content of the metal ions in the functionality-imparting composition of the present invention is preferably 0.1 molar or more, more preferably 0.2 molar or more, and even more preferably 0.5 molar or more, relative to the melanin precursor, from the viewpoint of imparting high antibacterial, deodorizing, or antistatic properties, and is preferably 1.5 molar or less, more preferably 1.2 molar or less, and even more preferably 1.0 molar or less, from the viewpoint of reducing the burden of waste liquid. The content of the metal ions in the functionality-imparting composition is preferably 0.1 molar or more and 1.5 molar or less, more preferably 0.2 molar or more and 1.2 molar or less, and even more preferably 0.5 molar or more and 1.0 molar or less, relative to the melanin precursor.

[0023] In addition to the melanin precursor, solvent, and metal ions, the functionality-imparting composition of the present invention may contain, as necessary, additives such as oxidases such as tyrosinase that catalyze the oxidation reaction of the melanin precursor, surfactants, stabilizers, buffers, fragrances, feel-improving agents, chelating agents, solubilizers, and preservatives. Furthermore, in order to control the oxidation rate of the melanin precursor, the composition may contain antioxidants such as sodium ascorbate and sodium sulfite. The content of the additives may be appropriately set within a range that does not impair the object of the present invention.

[0024] The form of the functionality-imparting composition of the present invention is not particularly limited, and examples thereof include a liquid (e.g., a suspension or solution), a gel, a paste, a solid, and the like. From the viewpoint of ease of penetration of the melanin precursor into the target object, a liquid form is preferred.

[0025] The pH (20°C) of the functional performance-imparting composition of the present invention is preferably 2 or more, more preferably 4 or more, and even more preferably 6 or more, from the viewpoint of promoting the oxidation of melanin precursors, and is preferably 12 or less, more preferably 10 or less, and even more preferably 7 or less, from the viewpoint of suppressing the decomposition of melanin. The pH (20°C) of the functional performance-imparting composition is preferably 2 or more and 12 or less, more preferably 4 or more and 10 or less, and even more preferably 6 or more and 7 or less.

[0026] As shown in the examples described below, by using a melanin precursor to generate melanin inside an object, it is possible to impart high photothermal, antibacterial, deodorizing, and antistatic properties to the object. Furthermore, these functionalities are retained even after laundering, resulting in excellent washfastness. That is, it is believed that the melanin generated by oxidative polymerization of the melanin precursor is fixed inside the object, for example, inside fibers, and imparts photothermal, antibacterial, deodorizing, and antistatic properties to the object. Therefore, in the present invention, a melanin precursor is used to impart photothermal, antibacterial, deodorizing, or antistatic properties to an object. Furthermore, by applying a composition containing a melanin precursor to an object, it is possible to impart photothermal, antibacterial, deodorizing, or antistatic properties to the object.

[0027] Furthermore, by combining melanin and metal ions, the antibacterial, deodorizing, and antistatic properties of the target object are improved. In the present invention, the melanin precursor and the metal ions may be applied in either order, or simultaneously. If they are not applied simultaneously, the interval between their applications can be appropriately selected as long as the antibacterial, deodorizing, or antistatic properties of the melanin produced by oxidative polymerization of the melanin precursor are enhanced.

[0028] In the present invention, the term "photothermal performance" refers to the ability to absorb light, such as sunlight, and convert it into heat.

[0029] In the present invention, "antibacterial" means inhibiting bacterial growth. Target bacteria include gram-positive bacteria, gram-negative bacteria, and drug-resistant bacteria thereof. In the present invention, the antibacterial agent is suitable for Staphylococcus bacteria such as Staphylococcus aureus (S. aureus), Klebsiella bacteria such as Klebsiella pneumoniae (K. pneumoniae), Pseudomonas bacteria such as Pseudomonas aeruginosa (P. aeruginosa), Escherichia coli such as E. coli O157, and Moraxella bacteria such as Moraxella osloensis (M. osloensis). In particular, the antibacterial agent is more suitable for Staphylococcus aureus (S. aureus).

[0030] In the present invention, "deodorization" refers to making a target odor unnoticeable or weakening its perception. Examples of target odors include unpleasant odors such as sweat odor, aging odor, excretory odor, cigarette odor, and garbage odor, as well as the odors of their causative substances, such as ammonia, acetic acid, isovaleric acid, nonenal, hydrogen sulfide, methyl mercaptan, indole, acetaldehyde, pyridine, and trimethylamine. In the present invention, the deodorizing agent is suitable for deodorizing ammonia odor or unpleasant odors caused by ammonia.

[0031] In the present invention, "antistatic" refers to the function of controlling static electricity.

[0032] The subject matter to which the functionality-imparting composition of the present invention is applied is not particularly limited, as long as it requires or is desired to be imparted with photothermal, antibacterial, deodorizing, or antistatic properties. Preferred examples include fibers, leather, and blends thereof. Examples of fibers include natural fibers such as cotton, silk, hemp, wool, mulberry, mitsumata, and gampi; synthetic fibers such as nylon, polyester, and acrylic; regenerated cellulose fibers such as rayon; and cellulose fibers such as paper. Natural fibers such as cotton, silk, hemp, wool, mulberry, mitsumata, and gampi are preferred, with cotton, silk, hemp, and wool being more preferred. From the viewpoint of strength as clothing, the fiber thickness is preferably 0.1 μm or more, more preferably 1 μm or more, and even more preferably 2 μm or more. From the viewpoint of ease of penetration of melanin precursors, the fiber thickness is preferably 200 μm or less, more preferably 100 μm or less, and even more preferably 50 μm or less. Examples of leather include cowhide, pigskin, snakeskin, horseskin, goatskin, and crocodile leather.

[0033] A preferred embodiment of the present invention is a photoheating performance-imparting composition that imparts photoheating performance to fibers or leather. The photoheating temperature after photoheating performance is imparted by the photoheating performance-imparting composition of the present invention is preferably 7°C or higher, more preferably 9°C or higher. That is, the photoheating performance-imparting composition of the present invention is used, for example, to raise the photoheating temperature of an object to preferably 7°C or higher, more preferably 9°C or higher. The photoheating temperature is the temperature that rises upon irradiation with light, and can be measured by the method described in the examples below.

[0034] A preferred embodiment of the present invention is a composition for imparting antibacterial performance to fibers. The antibacterial activity value of the composition for imparting antibacterial performance of the present invention is preferably 2.0 or more. That is, the composition for imparting antibacterial performance of the present invention is used, for example, to impart antibacterial performance with an antibacterial activity value of 2.0 or more to an object. The antibacterial activity value is determined by a method in accordance with JIS L 1902 quantitative test (bacterial liquid absorption method). Specific measurement methods will be described in the examples below.

[0035] A preferred embodiment of the present invention is a deodorizing composition that imparts deodorizing performance to textiles. The odor reduction rate achieved by the deodorizing composition of the present invention is preferably 60% or more, more preferably 70% or more, and even more preferably 80% or more. That is, the deodorizing composition of the present invention is used, for example, to impart deodorizing performance with an odor reduction rate of 60% or more to a target object. The odor reduction rate can be determined, for example, by the test method specified in the Deodorizing Property Test - Textile Products (Textile Evaluation Technology Council Method). Specific measurement methods will be described in the examples below.

[0036] Furthermore, a preferred embodiment of the present invention is an antistatic performance-imparting composition that imparts antistatic performance to fibers. The antistatic performance of the antistatic performance-imparting composition of the present invention preferably satisfies a half-life of 10 seconds or less and a frictional electrification voltage of 3,000 V or less, or a half-life of 60 seconds or less and a frictional electrification voltage of 1,500 V or less. That is, the antistatic performance-imparting composition of the present invention is used, for example, to impart such antistatic performance to an object. In the present invention, the antistatic performance is determined by a frictional electrification voltage measurement method conforming to JIS L 1094 Method B, and the half-life is determined by a method conforming to JIS L 1094 Method A. Specific measurement methods will be described in the examples below.

[0037] (Method for imparting functionality) The method of the present invention for imparting photothermal performance, antibacterial performance, deodorizing performance, or antistatic performance to an object comprises applying a composition containing a melanin precursor to the object. As a result, melanin is produced and fixed inside the object, and the object can be imparted with high photothermal performance, antibacterial performance, deodorizing performance, or antistatic performance that is also robust to washing. Examples of objects are as described above.

[0038] The application method is not particularly limited, and may be any of a method of immersing an object in the composition containing the melanin precursor, a method of applying the composition containing the melanin precursor directly to the object, or a method of spraying the composition containing the melanin precursor onto the object. A method of immersing an object in a liquid composition containing the melanin precursor is preferred. This may be done while the composition is standing or under stirring. The application method may also be repeated multiple times, for example, two or three times.

[0039] The amount of the composition containing a melanin precursor used may be any amount that can impart photothermal performance, antibacterial performance, deodorizing performance, or antistatic performance to an object, and can be appropriately determined depending on the form of use. For example, in a method of immersing an object in a liquid composition containing a melanin precursor, the bath ratio of the composition, i.e., the mass ratio of composition / object, is preferably 4 or more, more preferably 6 or more, and even more preferably 8 or more, from the viewpoint of ease of immersion, and is preferably 30 or less, more preferably 25 or less, and even more preferably 20 or less, from the viewpoint of cost. The mass ratio of composition / object is preferably 4 or more and 30 or less, more preferably 6 or more and 25 or less, and even more preferably 8 or more and 20 or less.

[0040] The application time is preferably 0.5 hours or more, more preferably 1 hour or more, and even more preferably 2 hours or more from the viewpoint of sufficient oxidation of the melanin precursor, and is preferably within 24 hours, more preferably within 10 hours, even more preferably within 3 hours, and even more preferably within 2 hours from the viewpoint of productivity. The application time is preferably 0.5 hours to 24 hours, more preferably 1 hour to 10 hours, and even more preferably 2 hours to 3 hours.

[0041] The application temperature is preferably 5° C. or higher, more preferably 10° C. or higher, and even more preferably 15° C. or higher, from the viewpoint of sufficient oxidation of the melanin precursor, and is preferably 90° C. or lower, more preferably 40° C. or lower, and even more preferably 30° C. or lower, from the viewpoint of operability and safety. The application temperature is preferably 5° C. or higher and 90° C. or lower, more preferably 10° C. or higher and 40° C. or lower, and even more preferably 15° C. or higher and 30° C.

[0042] After applying the composition containing the melanin precursor to the object, the composition is washed with water, dried, etc. as needed. As a result, the melanin produced from the melanin precursor is fixed inside the object, and the object is endowed with photothermal performance, antibacterial performance, deodorizing performance, or antistatic performance, resulting in an object endowed with such functionality. The content of the melanin precursor in the composition, the composition structure, the pH of the composition, etc. are the same as those described in the section on the functionality-imparting composition above.

[0043] (Method for producing functional fibers or photothermal leather) The method for producing fibers imparted with photothermal, antibacterial, deodorizing, or antistatic properties of the present invention includes applying a composition containing a melanin precursor to fibers. This generates and fixes melanin inside the fibers, resulting in fibers imparted with photothermal, antibacterial, deodorizing, or antistatic properties. The method for producing leather imparted with photothermal properties of the present invention includes applying a composition containing a melanin precursor to leather. This generates and fixes melanin inside the leather, resulting in leather imparted with photothermal properties. The photothermal, antibacterial, deodorizing, or antistatic fibers (antistatic fibers) of the present invention possess photothermal, antibacterial, deodorizing, or antistatic properties that are highly fast to washing, and are therefore useful as light-absorbing, heat-generating, antibacterial, deodorizing, or antistatic materials for clothing, etc. Examples of fibers or leathers, application means, and composition configurations are as described above.

[0044] In relation to the above-described embodiments, the present invention further discloses the following composition for imparting functionality, method for imparting functionality, or method for producing functional fibers. <1> A composition for imparting photoheating performance, containing a melanin precursor. <2> A composition for imparting antibacterial performance, containing a melanin precursor. <3> A composition for imparting deodorizing performance, containing a melanin precursor. <4> A composition for imparting antistatic performance, containing a melanin precursor. <5> The composition according to any one of <1> to <4>, wherein the melanin precursor contains one or more dihydroxyindoles selected from tyrosine and compounds represented by the following general formula (1) or salts thereof:

[0045]

[0046] (wherein the dashed line indicates the presence or absence of a π bond. R 1 represents a hydroxyl group or an acetoxy group. 2 represents a hydrogen atom or -COOR (wherein R is a hydrogen atom, a methyl group, or an ethyl group). 3represents a hydrogen atom, an acetyl group, a methyl group, or an ethyl group.) <6> The composition according to any one of <1> to <5>, wherein the melanin precursor contains one or two members selected from the group consisting of 5,6-dihydroxyindole and 5,6-dihydroxyindole-2-carboxylic acid. <7> The composition according to any one of <1> to <6>, wherein the content of the melanin precursor in the composition is 2 mM or more. <8> The composition according to any one of <1> to <7>, wherein the pH of the composition at 20°C is 2 or more and 12 or less. <9> The composition according to any one of <1> or <5> to <8>, which imparts photothermal properties to fibers or leather. <10> The composition according to any one of <2> to <8>, which imparts antibacterial properties, deodorizing properties, or antistatic properties to fibers. <11> The composition according to any one of <1> to <10>, further comprising an oxidase that catalyzes the oxidation reaction of the melanin precursor. <12> The composition according to any one of <6> to <11>, wherein, when 5,6-dihydroxyindole and 5,6-dihydroxyindole-2-carboxylic acid are used in combination as melanin precursors, the molar ratio of 5,6-dihydroxyindole to 5,6-dihydroxyindole-2-carboxylic acid is 50:50 to 99:1. <13> The composition according to any one of <9> to <12>, wherein the fiber to be imparted with photothermal performance, antibacterial performance, deodorizing performance, or antistatic performance is one or more types selected from the group consisting of cotton, silk, hemp, wool, mulberry, mitsumata, and gampi. <14> The composition according to any one of <9> and <11> to <12>, wherein the leather to be imparted with photothermal performance is one or more types selected from the group consisting of cowhide, pigskin, snakeskin, horseskin, goatskin, and crocodile leather. <15> The composition according to any one of <1> to <13>, further containing a metal ion.

[0047] <16> A method for imparting photothermal performance to an object, comprising applying a composition containing a melanin precursor to the object. <17> A method for imparting antibacterial performance to an object, comprising applying a composition containing a melanin precursor to the object. <18> A method for imparting deodorizing performance to an object, comprising applying a composition containing a melanin precursor to the object. <19> A method for imparting antistatic performance to an object, comprising applying a composition containing a melanin precursor to the object.

[0048] <20> The method according to any one of <16> to <19>, wherein the means for applying the composition containing a melanin precursor to the object is a method of immersing the object in the composition containing a melanin precursor, or a method of directly applying or spraying the composition containing a melanin precursor to the object. <21> The method according to any one of <17> to <20>, further comprising applying a metal ion.

[0049] <22> A method for producing fibers or leather imparted with photothermal performance, comprising applying a composition containing a melanin precursor to the fibers or leather. <23> A method for producing fibers imparted with antibacterial performance, comprising applying a composition containing a melanin precursor to fibers. <24> A method for producing fibers imparted with deodorizing performance, comprising applying a composition containing a melanin precursor to fibers. <25> A method for producing fibers imparted with antistatic performance, comprising applying a composition containing a melanin precursor to fibers.

[0050] <26> The method according to any one of <23> to <25>, further comprising applying a metal ion.

[0051] <27> Use of a composition containing a melanin precursor as a composition for imparting photoheating performance. <28> Use of a composition containing a melanin precursor as a composition for imparting antibacterial performance. <29> Use of a composition containing a melanin precursor as a composition for imparting deodorizing performance. <30> Use of a composition containing a melanin precursor as a composition for imparting antistatic performance. <31> The use according to any one of <27> to <30>, wherein the melanin precursor contains tyrosine, and one or more dihydroxyindoles selected from compounds represented by the following general formula (1) or salts thereof:

[0052]

[0053] (wherein the dashed line indicates the presence or absence of a π bond. R 1 represents a hydroxyl group or an acetoxy group. 2 represents a hydrogen atom or -COOR (wherein R is a hydrogen atom, a methyl group, or an ethyl group). 3 represents a hydrogen atom, an acetyl group, a methyl group, or an ethyl group.) <32> The use according to any one of <27> to <31>, wherein the melanin precursor contains one or two species selected from the group consisting of 5,6-dihydroxyindole and 5,6-dihydroxyindole-2-carboxylic acid. <33> The use according to any one of <27> to <32>, wherein the content of the melanin precursor in the composition is 2 mM or more. <34> The use according to any one of <27> to <33>, wherein the pH of the composition containing a melanin precursor at 20°C is 2 or more and 12 or less. <35> The use according to any one of <28> to <34>, wherein the composition containing a melanin precursor further contains a metal ion.

[0054] <Experimental Materials> - Fibers The following cotton, wool, silk, Japanese paper, and leather were used in Examples 1 to 10 and Comparative Examples 1 to 6. Cotton, wool, and silk were purchased from Okadaya Co., Ltd. (https: / / www.okadaya.co.jp / shop / c / c10 / ). Cotton: Fabric: Oeko-Tex sheeting (ECO6600). White was used in the fiber treatment experiments, and black was used as a comparative example. Wool: Fabric: Wool soft georgette (32-1266). Color: Ivory. Silk: Fabric: Silk spun twill 24 momme (KBTH241). Color: Natural. Japanese paper: Handmade Japanese paper for dyeing, medium thickness (Aikuma Dye Co., Ltd.) was used.

[0055] The following cotton and wool were used in Examples 11 to 24 and Comparative Examples 7 to 9. Cotton: Antibacterial test standard cloth obtained from the Japan Textile Evaluation Technology Council was used. Wool: Wool serge cloth purchased from Shikisensha Co., Ltd. was used.

[0056] 5,6-Dihydroxyindole (hereinafter referred to as "DHI") was prepared according to the method described in the prior art (Japanese Patent No. 7212628). Details are as follows: Tyrosinase (manufactured by SIGMA Co., Ltd., product number T3825) was used.

[0057] <DHI Preparation Method> A 5L glass three-neck flask was equipped with a stirrer equipped with a half-moon blade and used as a reactor. 2L of water was charged into the reactor, and nitrogen gas was vented from the top of the flask. DOPA was added to the reactor to a concentration of 0.33 wt% and dissolved by stirring at 200 rpm. The liquid temperature was adjusted to 35°C using a hot water bath. An oxidant solution was prepared by dissolving 16.8 wt% potassium hexacyanoferrate(III) and 7.2 wt% potassium bicarbonate in water. 0.288 mL of the oxidant solution was added to the reactor containing the DOPA aqueous solution and reacted for 4 hours to obtain an aqueous DHI solution. The pH was adjusted to 5.0 by adding 10 wt% phosphoric acid solution to the DHI aqueous solution. The following operations were performed in a glove box with an oxygen concentration of 0.1% or less using nitrogen venting. The DHI aqueous solution was filtered through a PES 0.2 μm filter. The filtered DHI aqueous solution was added to a 5L glass bottle, followed by the addition of 2L of ethyl acetate as an extractant. The bottle was then manually shaken to agitate the solution and perform extraction. The bottle was then left to stand, and 1.5L of the resulting upper layer (ethyl acetate layer) was collected in another glass bottle. 0.7L of wash water (salt concentration: 8.33 wt%, dipotassium hydrogen phosphate / potassium dihydrogen phosphate (mass ratio) = 5.12) prepared by dissolving dipotassium hydrogen phosphate and potassium dihydrogen phosphate in water was added, and the bottle was manually shaken to agitate and wash the solution. The bottle was then left to stand, and 1.0L of the resulting upper layer (ethyl acetate layer) was collected in a recovery flask. The collected ethyl acetate layer was completely evaporated using an evaporator (water bath temperature 45°C). 20wt% ethanol was added to the dried product to adjust the DHI concentration to 1wt%. The pH was adjusted to 8 by dropwise addition of 6N aqueous sodium hydroxide, resulting in a 1% DHI solution.

[0058] Examples 1 to 10 and Comparative Examples 1 to 6: A 1% DHI solution (67 mM) was diluted with water to the concentrations shown in Table 1 to prepare a DHI treatment solution. A treatment solution containing tyrosine as the active ingredient was also prepared. Tyrosine was added to 20 mM potassium phosphate buffer (pH 7.0) to a concentration of 26.2 mM, and tyrosinase was further added to a concentration of 1000 U / mL.

[0059] <Textile Treatment Method> For the photoheat-generating performance-imparting compositions other than those of Comparative Example 2, the treatment solution was added to approximately 15 x 15 cm pieces of cotton, wool, silk, leather, or Japanese paper (hereinafter also referred to as fibers, etc.) in an amount 30 times the mass of the fibers, etc. (bath ratio 30), and the mixture was left to stand at 30°C for 24 hours. After treatment, the fibers, etc. were thoroughly washed with tap water and air-dried. For Comparative Example 2, the black cotton fabric was cut to approximately 15 x 15 cm and used.

[0060] <Photo-generated temperature measurement> Evaluation was carried out in accordance with the light absorption heat retention test (Boken standard BQE A 036). The above-mentioned fibers were placed 30 cm away from a PRF300W reflector lamp (Iwasaki Electric) and irradiated with light at 100 V for 10 minutes (illuminance of the irradiated surface: 12 klx). A thermocouple was placed on the back of the fibers, and the temperature rise was measured from the temperature difference before and after irradiation. The photo-generated temperature was calculated as (temperature rise of treated fabric) - (temperature rise of untreated fabric).

[0061] <Color measurement method> The L, a, and b values ​​of the above fibers were measured using a color difference meter (CR-400, manufactured by Konica Minolta). The difference in L, a, and b values ​​from the fibers before and after dyeing was defined as Δ, and the color difference ΔE = {(ΔL)} 2 + (Δa) 2 +(Δb) 2} 0.5 was calculated.

[0062] <Washing method> The fabrics were washed repeatedly using a washing machine (Hitachi PS-50AS). Washing: 10 L of water, 5 g of detergent (Kao Corporation Attack Zero) for 10 min. Rinse: 10 L of water, 5 min, once.

[0063] <Results> Before and after treatment, the temperature rises of cotton, wool, silk fiber cloth, leather, and Japanese paper when irradiated with light were measured, and the photothermal temperature was evaluated. The results are shown in Table 1.

[0064]

[0065] As can be seen from Table 1, the use of an aqueous solution containing a melanin precursor gave the target object photothermal properties. In particular, the use of DHI showed remarkable photothermal properties.

[0066] The fibers of Examples 6, 7 and 8 were washed repeatedly, and the changes in the photo-generated temperature were measured. The results are shown in Table 2.

[0067]

[0068] From Table 2, it was confirmed that the photoheat generating performance was stably maintained even after washing.

[0069] <Color measurement method> The L, a, and b values ​​of the above fiber were measured using a color difference meter (CR-400 manufactured by Konica Minolta). The difference in L, a, and b values ​​from the fiber before dyeing was defined as Δ, and the color difference ΔE = {(ΔL)} 2 + (Δa) 2 +(Δb) 2} 0.5 was calculated.

[0070] <Method for evaluating antibacterial performance> The antibacterial activity of the fiber was evaluated according to the bacterial liquid absorption method (quantitative test) of JIS L1902:2015. The bacterial species used was Staphylococcus aureus NBRC12732, and the bacterial count was measured using the pour plate culture method. The antibacterial activity was calculated using the following formula.

[0071] Number of bacteria before incubation on standard cotton fabric before treatment: C0 Number of bacteria after 18 hours of incubation on standard cotton fabric before treatment: Ct Number of bacteria before incubation on treated cotton fabric before treatment: T0 Number of bacteria after 18 hours of incubation on treated cotton fabric before treatment: Tt Antibacterial activity = (LogCt-LogC0)- (LogTt-LogT0)

[0072] <Method for evaluating deodorizing performance> The deodorizing performance of textile fabrics was evaluated in accordance with the Deodorizing Test for Textile Products (Textile Evaluation Technology Council Method). Ammonia was used as the test gas, and the concentration was quantified using the detector tube method.

[0073] <Method for evaluating antistatic properties> According to JIS L 1094 Method A, a voltage of 10 kV was applied to a test piece for 30 seconds, and the time it took for the charged voltage to decrease by half (half-life) was measured. In addition, according to JIS L 1094 Method B, the frictional electrification voltage was measured using cotton as the test fabric.

[0074] Examples 11-15 and Comparative Examples 7 and 8 <Fiber Treatment Method> The following procedures were performed using a glove box to avoid contact of the DHI solution and fiber pieces with oxygen. A 0.05 M sodium phosphate buffer (pH 9.0) containing DHI at the concentrations shown in Table 3 was prepared as a DHI treatment solution. The DHI treatment solution was added to approximately 21 x 30 cm of fiber at a bath ratio of 20 and allowed to stand at room temperature for 3 hours. FeSO4 was then added to the concentration shown in Table 3 and allowed to stand for 30 minutes. The fiber was then exposed to air and allowed to stand for 30 minutes, after which it was thoroughly washed with tap water and air-dried. A treatment solution containing tyrosine as the active ingredient was also prepared. Tyrosine was added to 0.05 M sodium phosphate buffer (pH 7.0) to a concentration of 12.0 mM, and tyrosinase was added to a concentration of 100 U / mL. The treatment solution was added to a fiber measuring approximately 21 x 30 cm so that the bath ratio was 20, and the fiber was then reciprocally shaken at 25°C and 100 rpm for 20 hours. Thereafter, the fiber was thoroughly washed with tap water and air-dried.

[0075] <Washing Method> The treated fabrics were repeatedly washed using a washing machine NA-W50B1 (manufactured by Panasonic). Washing: 5 mL of a solution of 20 mL of Emal 20C (active ingredient: polyoxyethylene alkyl ether sulfate) and 30 mL of distilled water was added dropwise to 20 L of water, and the fabric was washed for 10 minutes in standard mode. Rinse: 20 L of water was added, and the fabric was washed for 2 minutes in standard mode.

[0076] The changes in bacterial counts and antibacterial activity were evaluated on the standard cotton fabric and the DHI-treated cotton fabric. The results are shown in Table 3.

[0077]

[0078] As is clear from Table 3, bacterial growth was inhibited in fibers treated with a melanin precursor, demonstrating antibacterial effects. In particular, high antibacterial activity was observed when DHI was used. Furthermore, while treatment with iron ions alone showed almost no antibacterial effect, the combination of iron ions with DHI demonstrated significant antibacterial activity. Furthermore, the results of washing the fibers of Example 14 10 times (Example 15) confirmed that the antibacterial performance was stably maintained even after washing.

[0079] Examples 16-20 <Fiber Treatment Method> The following procedures were carried out in a glove box, avoiding contact of the DHI solution and fiber pieces with oxygen. A 0.05 M sodium phosphate buffer solution (pH 9.0) containing DHI at the concentrations shown in Table 4 was prepared as a DHI treatment solution. The DHI treatment solution was added to approximately 15 x 35 cm of fiber at a bath ratio of 20 and allowed to stand at room temperature for 3 hours. FeSO4 was then added to the concentration shown in Table 4 and allowed to stand for 30 minutes. The fiber was then removed from the air and allowed to stand for 30 minutes, after which it was thoroughly washed with tap water and air-dried. A treatment solution containing tyrosine as the active ingredient was also prepared. Tyrosine was added to 0.05 M sodium phosphate buffer solution (pH 7.0) to a concentration of 12.0 mM, and tyrosinase was added to a concentration of 100 U / mL. The treatment solution was added to a fiber measuring approximately 15 x 35 cm so that the bath ratio was 20, and the fiber was then reciprocally shaken at 25°C and 100 rpm for 20 hours. Thereafter, the fiber was thoroughly washed with tap water and air-dried.

[0080] <Washing Method> In the same manner as in Example 15, the treated cloth was repeatedly washed.

[0081] The ammonia deodorizing performance of the standard cotton fabric of Comparative Example 7 and the DHI-treated cotton fabric was evaluated. The results are shown in Table 4.

[0082]

[0083] As is clear from Table 4, the gas concentration was significantly reduced in the melanin precursor-treated fibers, demonstrating a deodorizing effect. In particular, a high deodorizing effect was observed when DHI was used. Furthermore, the combined use of DHI and iron ion improved the deodorizing effect. Furthermore, the results of washing the fibers of Example 19 10 times (Example 20) confirmed that the deodorizing performance was stably maintained even after washing.

[0084] Examples 21-24 and Comparative Example 9 <Fiber Treatment Method> The following procedures were performed using a glove box, avoiding contact of the DHI solution and fiber pieces with oxygen. A 0.05 M sodium phosphate buffer (pH 9.0) containing DHI at the concentrations shown in Table 5 was prepared as a DHI treatment solution. The DHI treatment solution was added to a fiber measuring approximately 120 x 120 cm at a bath ratio of 20 and allowed to stand at room temperature for 3 hours. FeSO4 was then added to the concentration shown in Table 5 and allowed to stand for 30 minutes. The fiber was then exposed to air and allowed to stand for 30 minutes, after which it was thoroughly washed with tap water and air-dried. A treatment solution containing tyrosine as the active ingredient was also prepared. Tyrosine was added to 0.05 M sodium phosphate buffer (pH 7.0) to a concentration of 12.0 mM, and tyrosinase was added to a concentration of 100 U / mL. The treatment solution was added to a fiber measuring approximately 120 x 120 cm so that the bath ratio was 20, and the fiber was then reciprocally shaken at 25°C and 100 rpm for 20 hours. Thereafter, the fiber was thoroughly washed with tap water and air-dried.

[0085] <Washing Method> In the same manner as in Example 15, the treated cloth was repeatedly washed.

[0086] The half-life and frictional electrification voltage were measured for the woolen fabric and the DHI-treated woolen fabric. The results are shown in Table 5.

[0087]

[0088] As is clear from Table 5, the changes in half-life and electrostatic potential confirmed that DHI treatment exhibited an antistatic effect. Furthermore, the combined use of DHI and metal ions improved antistatic performance. Furthermore, the results of washing the fibers of Example 23 10 times (Example 24) confirmed that the antistatic performance was stably maintained even after washing.

Claims

1. A photothermal performance imparting composition containing a melanin precursor.

2. A composition for imparting antibacterial properties containing a melanin precursor.

3. A composition for imparting deodorizing performance containing a melanin precursor.

4. A composition for imparting antistatic properties containing a melanin precursor.

5. A composition according to any one of claims 1 to 4, wherein the melanin precursor contains tyrosine and one or more dihydroxyindoles selected from the group consisting of compounds represented by the following general formula (1) and salts thereof: (wherein the dashed line indicates the presence or absence of a π bond. R 1 represents a hydroxyl group or an acetoxy group. 2 represents a hydrogen atom or -COOR (wherein R is a hydrogen atom, a methyl group, or an ethyl group). 3 represents a hydrogen atom, an acetyl group, a methyl group, or an ethyl group.

6. The composition according to any one of claims 1 to 5, wherein the melanin precursor contains one or two members selected from the group consisting of 5,6-dihydroxyindole and 5,6-dihydroxyindole-2-carboxylic acid.

7. The composition according to any one of claims 1 to 6, wherein the content of melanin precursor in the composition is 2 mM or more.

8. The composition according to any one of claims 1 to 7, wherein the pH of the composition at 20°C is 2 or more and 12 or less.

9. The composition according to any one of claims 2 to 8, further comprising a metal ion.

10. The composition according to any one of claims 1 to 9, which imparts photothermal, antibacterial, deodorizing or antistatic properties to textiles.

11. The composition according to claim 1, which imparts photothermal properties to leather.

12. A method for imparting photothermal properties to an object, comprising applying a composition containing a melanin precursor to the object.

13. A method for imparting antibacterial properties to an object, comprising applying to the object a composition containing a melanin precursor.

14. A method for imparting deodorizing properties to an object, comprising applying a composition containing a melanin precursor to the object.

15. A method for imparting antistatic properties to an object, comprising applying a composition containing a melanin precursor to the object.

16. The method of any one of claims 13 to 15, further comprising applying metal ions.

17. A method for producing fibers or leather having photothermal properties, comprising applying a composition containing a melanin precursor to the fibers or leather.

18. A method for producing a fiber having antibacterial properties, comprising applying a composition containing a melanin precursor to the fiber.

19. A method for producing a fiber having deodorizing properties, comprising applying a composition containing a melanin precursor to the fiber.

20. A method for producing fibers having antistatic properties, comprising applying a composition containing a melanin precursor to the fibers.

21. The method of any one of claims 18 to 20, further comprising applying metal ions.

22. Use of a composition containing a melanin precursor as a composition for imparting photothermal performance.

23. Use of a composition containing a melanin precursor as a composition for imparting antibacterial properties.

24. Use of a composition containing a melanin precursor as a composition for imparting deodorizing performance.

25. Use of a composition containing a melanin precursor as a composition for imparting antistatic properties.

26. The use according to any one of claims 22 to 25, wherein the melanin precursor contains tyrosine and, as dihydroxyindoles, one or more compounds selected from the group consisting of compounds represented by the following general formula (1) and salts thereof: (wherein the dashed line indicates the presence or absence of a π bond. R 1 represents a hydroxyl group or an acetoxy group. 2 represents a hydrogen atom or -COOR (wherein R is a hydrogen atom, a methyl group, or an ethyl group). 3 represents a hydrogen atom, an acetyl group, a methyl group, or an ethyl group.

27. The use according to any one of claims 22 to 26, wherein the melanin precursor contains one or two members selected from the group consisting of 5,6-dihydroxyindole and 5,6-dihydroxyindole-2-carboxylic acid.

28. The use according to any one of claims 22 to 27, wherein the content of melanin precursor in the composition is 2 mM or more.

29. The use according to any one of claims 22 to 28, wherein the pH of the composition containing the melanin precursor at 20°C is 2 or more and 12 or less.

30. The use according to any one of claims 23 to 29, wherein the composition containing a melanin precursor further contains a metal ion.

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