Fiber for artificial hair and hair ornament

Abstract

To provide a fiber for artificial hair containing zinc oxide particles and having antibacterial properties while suppressing coloring, and to provide a hair ornament including the fiber for artificial hair.SOLUTION: A fiber for artificial hair comprising: a resinous material; and zinc oxide particles, wherein an average primary particle diameter of the zinc oxide particles is 200nm or less, and a content of the zinc oxide particles is 0.30 to 7.0% by mass. The hair ornament includes the fiber for artificial hair.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to fibers for artificial hair, hair accessories, etc. [Background technology]

[0002] Artificial hair fibers (fibers used for artificial hair) can be used in hair accessories. The use of various resin materials for artificial hair fibers has been investigated to obtain an appearance similar to that of human hair (see, for example, Patent Document 1 below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-131824 Summary of the Invention [Problem to be solved by the invention]

[0004] Consumers who use hair accessories may not wash their hair frequently, which can lead to the inability to keep their scalp or hair accessories clean, which can lead to bacterial growth and the generation of unpleasant odors, etc. Therefore, antibacterial properties are required for artificial hair fibers used in hair accessories.

[0005] In response to this, the present inventors have focused on using zinc oxide particles as a constituent material of artificial hair fibers. However, according to the findings of the present inventors, artificial hair fibers containing zinc oxide particles may be colored (e.g., may be colored white) compared to artificial hair fibers that do not contain zinc oxide particles. Therefore, it is necessary to suppress coloration of artificial hair fibers containing zinc oxide particles in order to maintain an excellent appearance as artificial hair fibers.

[0006] One aspect of the present invention is to provide an artificial hair fiber containing zinc oxide particles, which is inhibited from discoloring and has antibacterial properties. Another aspect of the present invention is to provide a hair accessory comprising such an artificial hair fiber. [Means for solving the problem]

[0007] In some aspects, the present invention relates to the following [1] to [7], etc. [1] A fiber for artificial hair, comprising a resin material and zinc oxide particles, the zinc oxide particles having an average primary particle size of 200 nm or less, and the zinc oxide particle content being 0.30 to 7.0 mass %. [2] The artificial hair fiber according to [1], wherein the proportion of particles with a primary particle size of 250 nm or less among the zinc oxide particles is 90% or more. [3] The fiber for artificial hair according to [1] or [2], wherein the proportion of particles with a primary particle size of 100 nm or less among the zinc oxide particles is 90% or more. [4] The fiber for artificial hair according to any one of [1] to [3], wherein the zinc oxide particles have a span value of 5 or less. [5] The fiber for artificial hair according to any one of [1] to [4], wherein the zinc oxide particles include particles whose surfaces are at least partially surface-treated. [6] The artificial hair fiber according to [5], wherein the zinc oxide particles include particles whose surfaces are at least partially surface-treated with a silicone compound. [7] The fiber for artificial hair according to any one of [1] to [6], wherein the resin material contains a non-crosslinked vinyl chloride resin having a viscosity average degree of polymerization of 450 to 1700, and the content of the non-crosslinked vinyl chloride resin is 60 to 99 mass %. [8] A hair accessory comprising the artificial hair fiber according to any one of [1] to [7]. [Effects of the Invention]

[0008] According to one aspect of the present invention, there is provided an artificial hair fiber containing zinc oxide particles, which is inhibited from coloring and has antibacterial properties. According to another aspect of the present invention, there is provided a hair accessory comprising such an artificial hair fiber. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail.

[0010] A numerical range "A or greater" means a range exceeding A and A. A numerical range "A or less" means a range exceeding A and A. In the numerical ranges described in this specification, the upper or lower limit of a certain numerical range can be arbitrarily combined with the upper or lower limit of another numerical range. In the numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with a value shown in the examples. "A or B" may include either A or B, or both. Unless otherwise specified, the materials exemplified in this specification can be used alone or in combination of two or more. When multiple substances corresponding to each component are present in the composition, the content of each component in the composition refers to the total amount of the multiple substances present in the composition, unless otherwise specified. The term "process" does not only refer to an independent process, but also includes processes that cannot be clearly distinguished from other processes as long as the intended effect of the process is achieved. "(Meth)acrylic acid" refers to at least one of acrylic acid and its corresponding methacrylic acid. The same applies to other similar expressions such as "(meth)acrylate."

[0011] The artificial hair fiber according to this embodiment contains a resin material and zinc oxide particles. In the artificial hair fiber according to this embodiment, the average primary particle size of the zinc oxide particles (average primary particle size of all zinc oxide particles contained in the artificial hair fiber) is 200 nm or less, and the content of the zinc oxide particles is 0.30 to 7.0 mass% based on the total mass of the artificial hair fiber. The artificial hair fiber according to this embodiment can be used as artificial hair (for example, a base fiber for artificial hair) and can also be used to obtain artificial hair. The artificial hair fiber according to this embodiment may be a fiber that has been stretched or an unstretched fiber.

[0012] The artificial hair fiber according to this embodiment can suppress discoloration (e.g., white coloring) of a material containing zinc oxide particles, and can suppress discoloration compared to artificial hair fibers that do not contain zinc oxide particles. The artificial hair fiber according to this embodiment can achieve a ΔL (difference in L values) of, for example, 0.7 or less (preferably, 0.6 or less, 0.5 or less, 0.4 or less, 0.3 or less, etc.) in the evaluation method described in the Examples below.

[0013] The artificial hair fiber according to this embodiment has antibacterial properties, for example, antibacterial properties against Staphylococcus aureus. According to the artificial hair fiber according to this embodiment, an antibacterial activity value of, for example, 2.0 or more (preferably, 2.5 or more, 3.0 or more, 3.5 or more, etc.) against Staphylococcus aureus can be obtained in the evaluation method described in the Examples below.

[0014] One aspect of the artificial hair fiber according to this embodiment has excellent combability. According to one aspect of the artificial hair fiber according to this embodiment, a resistance of, for example, 350 gf or less (preferably, 300 gf or less, 250 gf or less, 200 gf or less, 150 gf or less, etc.) can be obtained in the evaluation method described in the Examples below.

[0015] According to one aspect of the fiber for artificial hair of this embodiment, excellent spinnability can be obtained when undrawn fibers are obtained by melt spinning. According to one aspect of the fiber for artificial hair of this embodiment, the number of thread breakages per 12 hours can be, for example, 9 or less (preferably 8 or less, 6 or less, 4 or less, 2 or less, etc.), as evaluated by the method described in the Examples below.

[0016] The artificial hair fiber according to this embodiment contains a resin material, such as vinyl chloride resin, polyester resin, or polyamide resin.

[0017] The resin material may contain a vinyl chloride resin from the viewpoint of excellent processability into hair accessories. The vinyl chloride resin is a polymer having structural units derived from vinyl chloride, i.e., a polymer having vinyl chloride as a monomer unit. The vinyl chloride resin can be obtained by bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, or the like.

[0018] Examples of vinyl chloride resins include homopolymers of vinyl chloride (homopolymers, polyvinyl chloride), copolymers of vinyl chloride with other monomers, and mixtures of these. Examples of copolymers of vinyl chloride with other monomers include copolymers of vinyl chloride with vinyl esters (e.g., vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl propionate copolymer), copolymers of vinyl chloride with (meth)acrylic acid compounds (e.g., (meth)acrylic acid, (meth)acrylic acid esters) (e.g., vinyl chloride-butyl acrylate copolymer, vinyl chloride-2-ethylhexyl acrylate copolymer), copolymers of vinyl chloride with the polyfunctional monomers described below, copolymers of vinyl chloride with olefins (e.g., vinyl chloride-ethylene copolymer, vinyl chloride-propylene copolymer), and vinyl chloride-acrylonitrile copolymer. Vinyl chloride resins do not necessarily have structural units derived from (meth)acrylic acid compounds.

[0019] The vinyl chloride resin may include a non-crosslinked vinyl chloride resin, a crosslinked vinyl chloride resin, or both a non-crosslinked vinyl chloride resin and a crosslinked vinyl chloride resin. The "non-crosslinked" in the non-crosslinked vinyl chloride resin means that the polymer chain has no branching points (e.g., branching points where side carbon chains branch from the main carbon chain) and is linear. The "crosslinked" in the crosslinked vinyl chloride resin means that the polymer chain has branching points (e.g., branching points where side carbon chains branch from the main carbon chain) and is non-linear.

[0020] Cross-linked vinyl chloride resins can be obtained by adding a polyfunctional monomer during the polymerization of vinyl chloride and then polymerizing the monomer. Examples of polyfunctional monomers include di(meth)acrylate compounds such as polyethylene glycol di(meth)acrylate and bisphenol A-modified di(meth)acrylate. Cross-linked vinyl chloride resins may be a mixture of a gel component having a cross-linked structure and primarily composed of structural units derived from vinyl chloride, and a polyvinyl chloride component (a component composed of structural units derived from vinyl chloride). The gel component tends to be insoluble in tetrahydrofuran, while the polyvinyl chloride component tends to be soluble in tetrahydrofuran.

[0021] The content of the non-crosslinked vinyl chloride resin may be within the following ranges based on the total mass of the vinyl chloride resin. From the viewpoint of easily suppressing coloration of the artificial hair fiber or easily achieving excellent spinnability, the content of the non-crosslinked vinyl chloride resin may be 50% by mass or more, more than 50% by mass, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, or 93% by mass or more. The content of the non-crosslinked vinyl chloride resin may be 99% by mass or less, 97% by mass or less, 96% by mass or less, or 95% by mass or less. From these viewpoints, the content of the non-crosslinked vinyl chloride resin may be 50 to 99% by mass, 70 to 99% by mass, 90 to 99% by mass, or 90 to 95% by mass.

[0022] The content of the cross-linked vinyl chloride resin may be within the following ranges based on the total mass of the vinyl chloride resin. The content of the cross-linked vinyl chloride resin may be 1% by mass or more, 3% by mass or more, 4% by mass or more, or 5% by mass or more. From the viewpoint of easily suppressing coloration of the artificial hair fiber or easily achieving excellent spinnability, the content of the cross-linked vinyl chloride resin may be 50% by mass or less, less than 50% by mass, 40% by mass or less, 30% by mass or less, 20% by mass or less, 10% by mass or less, or 7% by mass or less. From these viewpoints, the content of the cross-linked vinyl chloride resin may be 1 to 50% by mass, 1 to 30% by mass, 1 to 10% by mass, or 5 to 10% by mass.

[0023] The resin material may include a non-crosslinked vinyl chloride resin having the following viscosity-average degree of polymerization. The viscosity-average degree of polymerization may be 100 or more, 300 or more, 400 or more, 450 or more, 500 or more, 600 or more, 700 or more, or 800 or more. The viscosity-average degree of polymerization may be 3000 or less, 2500 or less, 2000 or less, 1700 or less, 1500 or less, 1200 or less, or 1100 or less. From these viewpoints, the viscosity-average degree of polymerization may be 100 to 3000, 100 to 1700, 100 to 1100, 450 to 3000, 450 to 1700, 450 to 1100, 800 to 3000, 800 to 1700, or 800 to 1100. The viscosity-average degree of polymerization can be calculated according to JIS K 6721 by measuring the specific viscosity of a solution obtained by dissolving 200 mg of a non-crosslinked vinyl chloride resin in 50 mL of nitrobenzene using an Ubbelohde viscometer in a thermostatic bath at 30°C.

[0024] The content of vinyl chloride resin in the resin material may be 50% by mass or more, more than 50% by mass, 70% by mass or more, 90% by mass or more, 95% by mass or more, 98% by mass or more, or 99% by mass or more, based on the total mass of the resin material. The resin material may be substantially composed of vinyl chloride resin (substantially 100% by mass of the resin material is vinyl chloride resin).

[0025] The resin material may include a mixture of vinyl chloride resin and components capable of forming a polymer alloy with the vinyl chloride resin, such as ethylene-vinyl acetate copolymer (EVA), acrylonitrile-butadiene rubber (NBR), thermoplastic polyurethane (TPU), thermoplastic polyester elastomer (TPEE), methyl methacrylate-butadiene-styrene resin (MBS), acrylonitrile-butadiene-styrene resin (ABS), acrylonitrile-styrene copolymer (AS), and polymethyl methacrylate (PMMA).

[0026] Examples of polyester resins include polyethylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, and polymethylene terephthalate.

[0027] Examples of polyamide resins include nylon 6, nylon 66, nylon 11, nylon 12, nylon 6 / 10, and nylon 6 / 12.

[0028] The content A of the resin material, the vinyl chloride resin (total content of vinyl chloride resins contained in the artificial hair fiber), or the content of the non-crosslinked vinyl chloride resin with the specific viscosity-average degree of polymerization (e.g., a non-crosslinked vinyl chloride resin with a viscosity-average degree of polymerization of 450 to 1700) may be within the following ranges based on the total mass of the artificial hair fiber. The content A may be 50% by mass or more, more than 50% by mass, 60% by mass or more, 70% by mass or more, 80% by mass or more, 85% by mass or more, 90% by mass or more, 91% by mass or more, 92% by mass or more, 93% by mass or more, or 94% by mass or more. The content A may be 99% by mass or less, 98% by mass or less, 96% by mass or less, 95% by mass or less, 94% by mass or less, 93% by mass or less, 92% by mass or less, or 91% by mass or less. From these viewpoints, the content A may be 50 to 99 mass%, 60 to 99 mass%, 80 to 99 mass%, 90 to 99 mass%, 50 to 95 mass%, 60 to 95 mass%, 80 to 95 mass%, 90 to 95 mass%, 50 to 94 mass%, 60 to 94 mass%, 80 to 94 mass%, or 90 to 94 mass%.

[0029] The artificial hair fiber according to this embodiment contains zinc oxide particles (particles containing zinc oxide). The zinc oxide particles may contain an oxide of zinc, and may contain ZnO or ZnO2.

[0030] The zinc oxide content in the zinc oxide particles may be 50% by mass or more, more than 50% by mass, 70% by mass or more, 90% by mass or more, 95% by mass or more, 98% by mass or more, or 99% by mass or more, based on the total mass of the zinc oxide particles. The zinc oxide particles may be substantially composed of zinc oxide (substantially 100% by mass of the zinc oxide particles is zinc oxide).

[0031] The zinc oxide particles have an average primary particle size of 200 nm or less from the viewpoint of suppressing discoloration of the artificial hair fiber or achieving antibacterial properties. From the viewpoint of easily suppressing discoloration of the artificial hair fiber, easily achieving antibacterial properties, easily achieving excellent combability, or easily achieving excellent spinnability, the zinc oxide particles may have an average primary particle size of 180 nm or less, 150 nm or less, 120 nm or less, 100 nm or less, 90 nm or less, 80 nm or less, 70 nm or less, 65 nm or less, 60 nm or less, 50 nm or less, 40 nm or less, 30 nm or less, 20 nm or less, or 18 nm or less. The zinc oxide particles may have an average primary particle size of 1 nm or more, 5 nm or more, 10 nm or more, 15 nm or more, 18 nm or more, 20 nm or more, 30 nm or more, 40 nm or more, 50 nm or more, 60 nm or more, 65 nm or more, 70 nm or more, 80 nm or more, 90 nm or more, or 100 nm or more. From these viewpoints, the average primary particle size of the zinc oxide particles may be 1 to 200 nm, 1 to 120 nm, 1 to 80 nm, 1 to 50 nm, 10 to 200 nm, 10 to 120 nm, 10 to 80 nm, 10 to 50 nm, 30 to 200 nm, 30 to 120 nm, or 30 to 80 nm. The average primary particle size of the zinc oxide particles is the average of the maximum diameters of the zinc oxide particles, and can be measured by the method described in the examples below.

[0032] The proportion of zinc oxide particles having a primary particle size of 250 nm or less (proportion of the number of particles) may be 90% or more, from the viewpoint of easily achieving antibacterial properties, excellent combability, or excellent spinnability. The proportion of zinc oxide particles having a primary particle size of 250 nm or less may be less than 90%.

[0033] The proportion of zinc oxide particles having a primary particle size of 100 nm or less (proportion of the number of particles) may be 90% or more, from the viewpoint of easily suppressing coloration of the artificial hair fiber, easily achieving antibacterial properties, easily achieving excellent combability, or easily achieving excellent spinnability. The proportion of zinc oxide particles having a primary particle size of 100 nm or less may be less than 90%.

[0034] From the viewpoint of easily suppressing coloration of artificial hair fibers, the span value of the zinc oxide particles may be 20 or less, 15 or less, 12 or less, 10 or less, 8 or less, 6 or less, 5 or less, or 4 or less. The span value of the zinc oxide particles may be 1 or more, 2 or more, 3 or more, 4 or more, 5 or more, 6 or more, 8 or more, or 10 or more. From these viewpoints, the span value of the zinc oxide particles may be 1 to 20, 1 to 10, 1 to 6, 4 to 20, 4 to 10, 4 to 6, 6 to 20, or 6 to 10. The span value is a numerical value expressed as "(D90-D10) / D50", where D90, D50, and D10 are the particle diameters at cumulative 90%, 50%, and 10% in the cumulative particle size distribution on a volume basis. The span value can be measured by the method described in the Examples below.

[0035] The zinc oxide particles may include particles that are not surface-treated, or may include particles having at least a portion (partially or entirely) of their surface treated from the viewpoint of easily suppressing discoloration of the artificial hair fiber, easily imparting antibacterial properties, easily imparting excellent combability, or easily imparting excellent spinnability. Particles having at least a portion (partially or entirely) of their surface treated with a surface treatment agent may have at least one compound selected from the group consisting of surface treatment agents and compounds derived from surface treatment agents on at least a portion of their surface. Examples of surface treatment agents include silicone compounds, organosilicon compounds (excluding silicone compounds), organotitanium compounds, silicon oxide, and aluminum hydroxide. The surface treatment agent may include a silicone compound from the viewpoint of easily suppressing discoloration of the artificial hair fiber, easily imparting antibacterial properties, easily imparting excellent combability, or easily imparting excellent spinnability. That is, the zinc oxide particles may include particles having at least a portion of their surface treated with a silicone compound.

[0036] Examples of silicone compounds include hydrogen dimethicone (dimethicone / methicone copolymer), methyl hydrogen polysiloxane (methicone), dimethyl polysiloxane (dimethicone), methylphenyl polysiloxane, triethoxysilylethyl polydimethylsiloxyethyl dimethicone, triethoxysilylethyl polydimethylsiloxyethyl hexyl dimethicone, acrylic silicone resin, triethoxycaprylylsilane, fluoroalkylsilane, etc. Silicone oil may be used as the silicone compound. From the viewpoint of easily suppressing coloration of artificial hair fibers, easily obtaining antibacterial properties, easily obtaining excellent combability, or easily obtaining excellent spinnability, hydrogen dimethicone (structure "-(SiO(CH3)2) m -(SiO(CH3)H) n -" (where m and n are integers of 1 or more)).

[0037] The content of zinc oxide particles is 0.30 to 7.0% by mass based on the total mass of the artificial hair fiber. When the content of zinc oxide particles is 0.30% by mass or more, antibacterial properties can be obtained. When the content of zinc oxide particles is 7.0% by mass or less, coloration of the artificial hair fiber can be suppressed and excellent combability can be obtained.

[0038] The content of zinc oxide particles may be in the following ranges based on the total mass of the artificial hair fiber: From the viewpoint of easily obtaining antibacterial properties, the content of zinc oxide particles may be 0.40% by mass or more, 0.50% by mass or more, 0.60% by mass or more, 0.80% by mass or more, 1.0% by mass or more, 1.2% by mass or more, 1.5% by mass or more, 1.8% by mass or more, 2.0% by mass or more, 2.5% by mass or more, 3.0% by mass or more, 3.5% by mass or more, 4.0% by mass or more, 4.5% by mass or more, or 5.0% by mass or more. From the viewpoint of easily suppressing coloration of the artificial hair fiber, easily obtaining excellent combability, or easily obtaining excellent spinnability, the content of zinc oxide particles may be 6.5% by mass or less, 6.0% by mass or less, 5.5% by mass or less, 5.0% by mass or less, 4.5% by mass or less, 4.0% by mass or less, 3.5% by mass or less, 3.0% by mass or less, 2.5% by mass or less, 2.0% by mass or less, 1.8% by mass or less, 1.5% by mass or less, 1.2% by mass or less, 1.0% by mass or less, 0.80% by mass or less, 0.60% by mass or less, or 0.50% by mass or less. From these viewpoints, the content of the zinc oxide particles may be 0.30 to 6.0 mass%, 0.30 to 5.0 mass%, 0.30 to 3.0 mass%, 0.30 to 1.0 mass%, 0.50 to 7.0 mass%, 0.50 to 6.0 mass%, 0.50 to 5.0 mass%, 0.50 to 3.0 mass%, 0.50 to 1.0 mass%, 1.0 to 7.0 mass%, 1.0 to 6.0 mass%, 1.0 to 5.0 mass%, 1.0 to 3.0 mass%, 3.0 to 7.0 mass%, 3.0 to 6.0 mass%, or 3.0 to 5.0 mass%.

[0039] The content of the zinc oxide particles may be in the following ranges relative to 100 parts by mass of the resin material or 100 parts by mass of the vinyl chloride resin: From the viewpoint of easily obtaining antibacterial properties, the content of the zinc oxide particles may be 0.30 parts by mass or more, 0.40 parts by mass or more, 0.50 parts by mass or more, 0.60 parts by mass or more, 0.80 parts by mass or more, 1.0 parts by mass or more, 1.2 parts by mass or more, 1.5 parts by mass or more, 1.8 parts by mass or more, 2.0 parts by mass or more, 2.5 parts by mass or more, 3.0 parts by mass or more, 3.5 parts by mass or more, 4.0 parts by mass or more, 4.5 parts by mass or more, or 5.0 parts by mass or more. From the viewpoint of easily suppressing coloration of the artificial hair fiber, easily obtaining excellent combing properties, or easily obtaining excellent spinnability, the content of zinc oxide particles may be 7.0 parts by mass or less, 6.5 parts by mass or less, 6.0 parts by mass or less, 5.5 parts by mass or less, 5.0 parts by mass or less, 4.5 parts by mass or less, 4.0 parts by mass or less, 3.5 parts by mass or less, 3.0 parts by mass or less, 2.5 parts by mass or less, 2.0 parts by mass or less, 1.8 parts by mass or less, 1.5 parts by mass or less, 1.2 parts by mass or less, 1.0 parts by mass or less, 0.80 parts by mass or less, 0.60 parts by mass or less, or 0.55 parts by mass or less. From these viewpoints, the content of the zinc oxide particles may be 0.30 to 7.0 parts by mass, 0.30 to 6.0 parts by mass, 0.30 to 5.0 parts by mass, 0.30 to 3.0 parts by mass, 0.30 to 1.0 parts by mass, 0.50 to 7.0 parts by mass, 0.50 to 6.0 parts by mass, 0.50 to 5.0 parts by mass, 0.50 to 3.0 parts by mass, 0.50 to 1.0 parts by mass, 1.0 to 7.0 parts by mass, 1.0 to 6.0 parts by mass, 1.0 to 5.0 parts by mass, 1.0 to 3.0 parts by mass, 3.0 to 7.0 parts by mass, 3.0 to 6.0 parts by mass, or 3.0 to 5.0 parts by mass.

[0040] The artificial hair fiber according to this embodiment may contain components other than those mentioned above (resin materials, zinc oxide particles, etc.), such as heat stabilizers, lubricants, antistatic agents, flame retardants, flame retardant assistants, ultraviolet absorbers, light stabilizers, fluorescent agents, antioxidants, plasticizers, etc.

[0041] Examples of the heat stabilizer include Ca-Zn-based heat stabilizers, hydrotalcite-based heat stabilizers, tin-based heat stabilizers, epoxy-based heat stabilizers, β-diketone-based heat stabilizers, etc. The heat stabilizer may contain at least one selected from the group consisting of Ca-Zn-based heat stabilizers and hydrotalcite-based heat stabilizers, from the viewpoint of extending the life of the artificial hair fiber and easily suppressing discoloration of the fiber, or easily suppressing thermal decomposition of the composition when forming the fiber.

[0042] Examples of Ca-Zn-based heat stabilizers include zinc stearate, calcium stearate, zinc 12-hydroxystearate, and calcium 12-hydroxystearate.

[0043] Examples of hydrotalcite-based heat stabilizers include complex salt compounds consisting of magnesium and / or alkali metals and aluminum or zinc, complex salt compounds consisting of magnesium and aluminum, and compounds obtained by dehydrating the water of crystallization of these complex salt compounds.

[0044] Examples of tin-based heat stabilizers include mercaptotin-based heat stabilizers such as dimethyltin mercapto, dimethyltin mercaptide, dibutyltin mercapto, dioctyltin mercapto, dioctyltin mercapto polymer, and dioctyltin mercaptoacetate; maleatetin-based heat stabilizers such as dimethyltin maleate, dibutyltin maleate, dioctyltin maleate, and dioctyltin maleate polymer; and lauratetin-based heat stabilizers such as dimethyltin laurate, dibutyltin laurate, and dioctyltin laurate.

[0045] Examples of epoxy-based heat stabilizers include epoxidized soybean oil and epoxidized linseed oil.

[0046] Examples of the β-diketone-based heat stabilizer include stearoylbenzoylmethane and dibenzoylmethane.

[0047] The content of the heat stabilizer may be 0.1 to 5.0 parts by mass or 1.0 to 3.0 parts by mass per 100 parts by mass of the resin material or 100 parts by mass of the vinyl chloride resin. By having the content of the heat stabilizer within these ranges, the life of the artificial hair fiber is extended, discoloration of the fiber is easily suppressed, and thermal decomposition of the composition during fiber formation is easily suppressed.

[0048] Examples of the lubricant include metal soap-based lubricants, higher fatty acid-based lubricants, ester-based lubricants, higher alcohol-based lubricants, etc. By using such lubricants, a good feel to the touch can be easily obtained, and the molten state of the composition and the adhesion state between the composition and metal surfaces of the screw, cylinder, die, etc. in the extruder can be easily controlled.

[0049] Examples of metal soap-based lubricants include metal soaps, such as stearates, laurates, palmitates, and oleates of Na, Mg, Al, Ca, Ba, and the like.

[0050] Examples of higher fatty acid lubricants include saturated fatty acids such as stearic acid, palmitic acid, myristic acid, lauric acid, and capric acid; unsaturated fatty acids such as oleic acid; and mixtures thereof.

[0051] Examples of higher alcohol lubricants include stearyl alcohol, palmityl alcohol, myristyl alcohol, lauryl alcohol, and oleyl alcohol.

[0052] Examples of ester-based lubricants include ester-based lubricants composed of alcohol and fatty acid; pentaerythritol-based lubricants such as monoesters, diesters, triesters, tetraesters of pentaerythritol or dipentaerythritol with higher fatty acids, or mixtures thereof; and montanic acid wax-based lubricants such as esters of montanic acid and higher alcohols (stearyl alcohol, palmityl alcohol, myristyl alcohol, lauryl alcohol, oleyl alcohol, etc.).

[0053] The content of the lubricant may be 0.2 to 5.0 parts by mass or 1.0 to 4.0 parts by mass per 100 parts by mass of the resin material or 100 parts by mass of the vinyl chloride resin. When the content of the lubricant is within these ranges, die pressure increases, yarn breakage, nozzle pressure increases, and the like during yarn obstruction are easily suppressed, which tends to improve production efficiency.

[0054] The monofilament fineness of the artificial hair fiber according to this embodiment may be 300 decitex or less, or 200 decitex or less when unstretched, from the viewpoint that the draw ratio can be reduced to obtain finer artificial hair fibers, and that the artificial hair fiber is less likely to develop gloss after stretching.

[0055] The monofilament fineness of the artificial hair fiber according to this embodiment after drawing may be in the following ranges. The monofilament fineness may be 20 dtex or more, 30 dtex or more, 50 dtex or more, or 60 dtex or more. The monofilament fineness may be 100 dtex or less, 90 dtex or less, 80 dtex or less, or 70 dtex or less. From these viewpoints, the monofilament fineness may be 20 to 100 dtex.

[0056] The method for producing artificial hair fibers according to this embodiment may include a spinning step of spinning a composition containing a resin material and zinc oxide particles. In the spinning step, the composition containing a resin material and zinc oxide particles can be melt-spun (melt-deformed).

[0057] The method for producing artificial hair fibers according to this embodiment may include a kneading step of melt-kneading a composition containing a resin material and zinc oxide particles prior to the spinning step. Various common kneaders can be used as the melt-kneading device. Examples of kneaders include single-screw extruders, twin-screw extruders, rolls, Banbury mixers, and kneaders.

[0058] The method for producing fibers for artificial hair according to this embodiment may include, after the spinning step, a drawing step in which the yarn (undrawn yarn) obtained in the spinning step is subjected to a drawing treatment.

[0059] The draw ratio in the drawing step may be 1.5 times or more, or 2.0 times or more, from the viewpoint of facilitating the development of fiber strength. The draw ratio may be 5.0 times or less, or 4.0 times or less, from the viewpoint of preventing yarn breakage during drawing. From these viewpoints, the draw ratio may be 1.5 to 5.0 times.

[0060] The drawing treatment may be carried out by a two-step method in which the undrawn yarn is once wound onto a bobbin and then drawn in a step not subsequent to the spinning step, or by a direct spinning drawing method in which the undrawn yarn is drawn in a step subsequent to the spinning step without being wound onto a bobbin. The drawing treatment may be carried out by a one-stage drawing method in which the yarn is drawn to the desired draw ratio in one step, or by a multi-stage drawing method in which the yarn is drawn to the desired draw ratio by two or more drawing steps.

[0061] The temperature for the drawing treatment may be 80 to 120° C. If the temperature is 80° C. or higher, it is easy to ensure sufficient fiber strength and yarn breakage is unlikely to occur. If the temperature is 120° C. or lower, it is easy to obtain a favorable fiber feel.

[0062] The method for producing an artificial hair fiber according to this embodiment may include a heat treatment step of annealing the yarn (drawn yarn) obtained in the drawing step after the drawing step. By performing the heat treatment step, the thermal shrinkage rate of the drawn yarn can be reduced.

[0063] The heat treatment temperature may be 100° C. or higher, or 120° C. or higher. The heat treatment temperature may be 200° C. or lower, or 150° C. or lower. From these viewpoints, the heat treatment temperature may be 100 to 200° C. The heat treatment may be carried out immediately after the stretching treatment, or may be carried out after taking up the film.

[0064] The hair accessory according to this embodiment comprises the artificial hair fiber according to this embodiment. The hair accessory according to this embodiment is an article that can be attached to or detached from the head, and may be in a form consisting of the artificial hair fiber according to this embodiment (for example, a fiber bundle of the artificial hair fiber). Examples of hair accessories include wigs, hairpieces, braids, hair extensions, and false hair. [Example]

[0065] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0066] <Production of artificial hair fibers> A vinyl chloride resin composition was obtained by mixing a non-crosslinked vinyl chloride resin (manufactured by Taiyo Vinyl Corporation, product name: TH1000, vinyl chloride homopolymer, viscosity-average degree of polymerization: 980-1080), a crosslinked vinyl chloride resin (manufactured by Shin-Etsu Chemical Co., Ltd., product name: GR800T), zinc oxide particles listed in Table 1, and additives (thermal stabilizer, lubricant, etc.) in a blender. This vinyl chloride resin composition was compounded using an extruder with a diameter of 65 mm at a cylinder temperature of 130-170°C to produce pellets. These pellets were melt-spun using an extruder with a diameter of 40 mm to obtain fiber A. The cylinder temperature during melt spinning was 150-195°C. Fiber A was heat-treated for approximately 0.5-1.5 seconds in a heating cylinder installed directly below the nozzle to obtain fiber B with a weight of 150 dtex. Fiber B was stretched 300% in an air atmosphere at 100°C, and then heat-shrunk in an air atmosphere at 120°C until the entire fiber length was 75% of its pre-treatment length, yielding a 67-dtex artificial hair fiber. The contents of non-crosslinked vinyl chloride resin, crosslinked vinyl chloride resin, and zinc oxide particles based on the total mass of the artificial hair fiber are shown in Table 1. The content of additives is the remainder obtained by subtracting the contents of non-crosslinked vinyl chloride resin, crosslinked vinyl chloride resin, and zinc oxide particles from the total mass of the artificial hair fiber.

[0067] As the zinc oxide particles, the following zinc oxide particles A to G were used. Zinc oxide particles A: Sakai Chemical Industry Co., Ltd., product name "ABZ-10", no surface treatment Zinc oxide particles B: Sakai Chemical Industry Co., Ltd., product name "ABZ-10-KS", surface treated with hydrogen dimethicone Zinc oxide particles C: Hakusui Tech Co., Ltd., product name "ZINCOX SUPER F-1", no surface treatment Zinc oxide particles D: Hakusui Tech Co., Ltd., product name "ZINCOX SUPER F-2", no surface treatment Zinc oxide particles E: Sakai Chemical Industry Co., Ltd., product name "NANOFINE-50", no surface treatment Zinc oxide particles F: Feilong Co., Ltd., product name "Nano Zinc Oxide Powder", no surface treatment Zinc oxide particles G: Sakai Chemical Industry Co., Ltd., product name "Zinc oxide type 1", no surface treatment

[0068] The primary particle size of zinc oxide particles was measured using the following procedure. First, artificial hair fibers were dissolved in tetrahydrofuran (THF) to recover powder. Next, the shape of the zinc oxide particles was identified by qualitative analysis of zinc element using a scanning electron microscope (SEM-EDS, Hitachi High-Tech Corporation, product name: FE-SEM (S-4800) + EDX). The primary particle size (maximum diameter) of 500 zinc oxide particles randomly selected from the SEM image was then measured. The average primary particle size and particle size distribution of the 500 zinc oxide particles were then obtained. Furthermore, for zinc oxide particles E and F, the span value "(D90 - D10) / D50" was calculated based on the particle size distribution. The information obtained for each zinc oxide particle is as follows. Table 2 shows whether the proportion of particles with a primary particle size of 250 nm or less was 90% or more, and whether the proportion of particles with a primary particle size of 100 nm or less was 90% or more.

[0069] Zinc oxide particles A: Average primary particle size 100 nm (proportion of particles with a primary particle size of 300 nm or less: 90%) Zinc oxide particles B: Average primary particle size 100 nm (proportion of particles with a primary particle size of 300 nm or less: 90%) Zinc oxide particles C: Average primary particle size 100 nm (proportion of particles with a primary particle size of 200 nm or less: 90%) Zinc oxide particles D: Average primary particle size 65 nm (proportion of particles with a primary particle size of 130 nm or less: 90%) Zinc oxide particles E: Average primary particle size 20 nm (proportion of particles with a primary particle size of 80 nm or less: 90%), span value 10 Zinc oxide particles F: Average primary particle size 18 nm (proportion of particles with a primary particle size of 50 nm or less: 90%), span value 4 Zinc oxide particles G: average primary particle size 750 nm

[0070] The above-mentioned zinc oxide particles A to G were separately prepared, and the average primary particle size and particle size distribution of 500 zinc oxide particles were measured in the same manner as for the above-mentioned zinc oxide particles A to G used to produce artificial hair fibers. As a result, it was confirmed that the average primary particle size and particle size distribution of the zinc oxide particles A to G used to produce artificial hair fibers were not significantly different from the average primary particle size and particle size distribution of the zinc oxide particles A to G not used to produce artificial hair fibers (significance level 0.05 in F-test and t-test).

[0071] <Evaluation> (Color) The above-mentioned artificial hair fibers were bundled to obtain a fiber bundle having a length of 250 mm and a mass of 25 g. The color of this fiber bundle was then measured using a spectrophotometer (manufactured by Kurabo Industries, product name: COLOR-7X, D-65 light source, measurement area 5 mm x 12 mm square) to determine the L value. Furthermore, artificial hair fibers were produced in the same manner as the above-mentioned artificial hair fibers, except that zinc oxide particles were not used, and the L value of this artificial hair fiber was measured. The color was evaluated based on the difference ΔL between these L values. ΔL is shown in Table 2.

[0072] (Antibacterial) The antibacterial properties of the above-mentioned artificial hair fibers were evaluated based on JIS L 1902. Staphylococcus aureus was used as the test bacterium, and the antibacterial activity value (difference in viable cell count) was measured before and after leaving the sample at 37°C for 18 hours. The results of the antibacterial activity value measurements are shown in Table 2. The "antibacterial activity value" is a value obtained by the following formula, which is defined by the bacterial liquid absorption method. Antibacterial activity value = (log Ct -logC0)-(logT t -logT0) C t : Common logarithm of the arithmetic mean of the viable bacterial counts of the three target samples after 18 hours of incubation C0: Common constant of the arithmetic mean of the viable bacterial counts of the three target samples immediately after inoculation T t : Common logarithm of the arithmetic mean of the viable bacterial counts of three test samples after 18 hours of incubation T0: Common logarithm of the arithmetic mean of the viable bacterial counts of the three test samples immediately after inoculation

[0073] (Combability) The artificial hair fibers described above were shaped using a gear machine (NEW YAKI BRAID CRIMPING M / C-2.5mm / SUNG JIN INDUSTRIAL CO., LTD.) under the following conditions: gear pitch 2.5 mm, preheating to 90°C, gear roll temperature 90°C, and gear roll rotation speed 1 mm / min. The fibers were then bundled to obtain a fiber bundle 300 mm long and weighing 10 g. The maximum resistance force (unit: gf) when combing from a position 90 mm from the tip of the fiber bundle toward the tip of the fiber bundle at a moving speed of 10 mm / sec and a moving distance of 100 mm was measured using a static and dynamic friction tester (manufactured by TRINITY-LAB, product name: TL201Tt). The resistance force measurement results are shown in Table 2. The lower the resistance force, the better the combability (touch, roughness) was judged to be.

[0074] (Spinnability) In the production of the above-mentioned artificial hair fiber, the occurrence of thread breakage per 12 hours during the melt spinning to produce Fiber A was visually observed. The number of thread breakages is shown in Table 2.

[0075] [Table 1]

[0076] [Table 2]

Claims

1. Contains a resin material and zinc oxide particles, the zinc oxide particles have an average primary particle size of 200 nm or less, The fiber for artificial hair has a content of the zinc oxide particles of 0.30 to 7.0% by mass.

2. 2. The artificial hair fiber according to claim 1, wherein the proportion of particles having a primary particle size of 250 nm or less in said zinc oxide particles is 90% or more.

3. 2. The artificial hair fiber according to claim 1, wherein the proportion of particles having a primary particle size of 100 nm or less in said zinc oxide particles is 90% or more.

4. 2. The artificial hair fiber according to claim 1, wherein the zinc oxide particles have a span value of 5 or less.

5. The artificial hair fiber according to claim 1 , wherein the zinc oxide particles include particles having at least a portion of their surfaces treated.

6. The artificial hair fiber according to claim 5 , wherein the zinc oxide particles include particles at least a portion of whose surface has been treated with a silicone compound.

7. the resin material contains a non-crosslinked vinyl chloride resin having a viscosity-average degree of polymerization of 450 to 1700, 2. The fiber for artificial hair according to claim 1, wherein the content of the non-crosslinked vinyl chloride resin is 60 to 99% by mass.

8. A hair accessory comprising the artificial hair fiber according to any one of claims 1 to 7.

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