Artificial hair fibers and head accessories

Abstract

One aspect of the present invention is an artificial hair fiber formed from a polyvinyl chloride resin composition. When dynamic viscoelasticity of the artificial hair fiber is measured under the following conditions, the loss tangent tanδ value X1 at 70°C is 0.06 or more and 0.12 or less, and the fiber has a peak in the temperature range of 90°C or more and 110°C or less. (Dynamic viscoelasticity measurement conditions) The measurement is performed at a temperature rise rate of 4°C / min and a frequency of 1 Hz, with a bundle of 40 artificial hair fibers sandwiched between the fibers.

Description

[Technical Field]

[0001] The present invention relates to an artificial hair fiber and a head ornament. [Background technology]

[0002] Polyvinyl chloride fibers have excellent strength and elongation, and are widely used as fibers for artificial hair that constitute head ornaments. Patent Document 1 discloses polyvinyl chloride fibers for artificial hair, which are made of a resin composition of a vinyl chloride resin and a cross-linked polyvinyl chloride resin with a specified viscosity average molecular weight, and have a cross-sectional shape that is a combination of a circle, a parabola, or an ellipse. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2006 / 093009 Summary of the Invention [Problem to be solved by the invention]

[0004] The properties required for artificial hair fibers are a pleasant feel when touched with the fingers and a good appearance that does not cause visual discomfort due to glare caused by light reflection. The inventors of the present invention have studied the feel and appearance of artificial hair fibers and have found that improving the feel when touched with the fingers results in increased glare, resulting in an undesirable appearance. In other words, the inventors' studies have revealed that there is a trade-off between pleasant feel and pleasant appearance in artificial hair fibers, and that it is difficult to improve these properties in a balanced manner. Therefore, an object of the present invention is to provide a fiber for artificial hair that exhibits a good balance between a good feel and an appearance with reduced glitter. [Means for solving the problem]

[0005] According to the present invention, there is provided an artificial hair fiber formed from a polyvinyl chloride resin composition, which has a loss tangent tanδ value X1 of 0.06 or more and 0.12 or less at 70°C when dynamic viscoelasticity is measured under the following conditions, and has a peak in the temperature range of 90°C or more and 110°C or less. (Dynamic viscoelasticity measurement conditions) The temperature rise rate is 4°C / min, the frequency is 1Hz, and measurements are taken by clamping a bundle of 40 artificial hair fibers.

[0006] Furthermore, according to the present invention, there is provided a head ornament using the above-mentioned artificial hair fiber. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a technology relating to fibers for artificial hair that exhibit a good balance between a good feel and an appearance with reduced glitter. [Brief explanation of the drawings]

[0008] The above-mentioned objects, as well as other objects, features and advantages, will become more apparent from the preferred embodiments described below and the accompanying drawings.

[0009] [Figure 1] Figure 1(a) is a schematic cross-sectional view of an artificial hair fiber having a spectacle-shaped cross section, and Figure 1(b) is a schematic cross-sectional view of an artificial hair fiber having a Y-shaped cross section. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail.

[0011] (artificial hair fibers) The artificial hair fiber according to the embodiment is formed from a polyvinyl chloride resin composition, which preferably contains a non-crosslinked polyvinyl chloride resin (A) (hereinafter simply referred to as polyvinyl chloride resin (A)) and a crosslinked polyvinyl chloride resin (B).

[0012] The polyvinyl chloride resin (A) is not particularly limited, and can be a homopolymer resin, which is a homopolymer of vinyl chloride, or any of the various copolymer resins known in the art. Representative examples of such copolymer resins include copolymer resins of vinyl chloride and vinyl esters, such as vinyl chloride-vinyl acetate copolymer resin and vinyl chloride-vinyl propionate copolymer resin; copolymer resins of vinyl chloride and acrylic esters, such as vinyl chloride-butyl acrylate copolymer resin and vinyl chloride-2-ethylhexyl acrylate copolymer resin; copolymer resins of vinyl chloride and olefins, such as vinyl chloride-ethylene copolymer resin and vinyl chloride-propylene copolymer resin; and vinyl chloride-acrylonitrile copolymer resin. Preferred polyvinyl chloride resins (A) include homopolymer resins, which are homopolymers of vinyl chloride, vinyl chloride-ethylene copolymer resin, and vinyl chloride-vinyl acetate copolymer resin. The comonomer content of such copolymer resins is not particularly limited and can be determined depending on the moldability into fibers and the properties of the fibers.

[0013] The lower limit of the viscosity-average degree of polymerization of the polyvinyl chloride resin (A) is preferably 450 or more, more preferably 500 or more, and even more preferably 550 or more. The upper limit of the viscosity-average degree of polymerization of the polyvinyl chloride resin (A) is preferably 1700 or less, more preferably 1650 or less, and even more preferably 1600 or less. By setting the viscosity-average degree of polymerization of the polyvinyl chloride resin (A) to 450 or more, the entanglement of the polyvinyl chloride resin (A) can be increased, thereby increasing strength. Furthermore, by setting the viscosity-average degree of polymerization of the polyvinyl chloride resin (A) to 1700 or less, appropriate gelation occurs, making the fibers less susceptible to breakage and improving productivity. When a polyvinyl chloride homopolymer resin is used as the polyvinyl chloride resin (A), the viscosity-average degree of polymerization is preferably in the range of 650 to 1450 in order to achieve moldability and fiber properties. When a copolymer is used as the polyvinyl chloride resin (A), the viscosity-average degree of polymerization is preferably in the range of 1,000 or more and 1,700 or less, although this depends on the content of the comonomer. The viscosity-average degree of polymerization was calculated according to JIS-K6721 by dissolving 200 mg of polyvinyl chloride resin (A) in 50 mL of nitrobenzene, measuring the specific viscosity of the resulting polymer solution using an Ubbelohde viscometer in a thermostatic bath at 30°C.

[0014] The polyvinyl chloride resin (A) can be produced by emulsion polymerization, bulk polymerization, suspension polymerization, etc. Taking into consideration the initial colorability of the fiber, a polymer produced by suspension polymerization is preferred.

[0015] (Crosslinked polyvinyl chloride resin (B)) The crosslinked polyvinyl chloride resin (B) can be easily obtained by adding a polyfunctional monomer to the suspension, microsuspension, or emulsion polymerization of vinyl chloride in an aqueous medium. The polyfunctional monomer used in this case is preferably a diacrylate compound such as polyethylene glycol diacrylate or bisphenol A-modified diacrylate. The crosslinked polyvinyl chloride resin (B) has a crosslinked structure and is a mixture of a gel component mainly composed of vinyl chloride insoluble in tetrahydrofuran (THF) and a polyvinyl chloride component soluble in tetrahydrofuran.

[0016] The lower limit of the viscosity average degree of polymerization of the component soluble in tetrahydrofuran in the crosslinked polyvinyl chloride resin (B) is preferably 500 or more, more preferably 550 or more, and even more preferably 600 or more. The upper limit of the viscosity average degree of polymerization is preferably 2300 or less, more preferably 2200 or less, and even more preferably 2100 or less. By adjusting the viscosity-average degree of polymerization of the component soluble in tetrahydrofuran to 500 or more, the weaving properties of the resulting artificial hair fiber can be made sufficient. On the other hand, by adjusting the viscosity-average degree of polymerization to 2300 or less, the occurrence of thread breakage during spinning can be suppressed.

[0017] The viscosity-average degree of polymerization of the component of the crosslinked polyvinyl chloride resin (B) that dissolves in tetrahydrofuran is measured as follows. 1 g of crosslinked polyvinyl chloride resin (B) was added to 60 mL of tetrahydrofuran and allowed to stand for approximately 24 hours. The crosslinked polyvinyl chloride resin (B) was then thoroughly dissolved using an ultrasonic cleaner. The resulting tetrahydrofuran solution was then centrifuged (at 30,000 rpm for 1 hour) to separate the insoluble matter from the tetrahydrofuran solution, and the supernatant tetrahydrofuran solvent was collected. The tetrahydrofuran solvent was then evaporated, and the viscosity-average degree of polymerization of the remaining resin component was measured using the same method as for the polyvinyl chloride resin (A) described above.

[0018] The lower limit of the content of the crosslinked polyvinyl chloride resin (B) per 100 parts by mass of the polyvinyl chloride resin (A) is preferably 2 parts by mass or more, more preferably 3 parts by mass or more, and even more preferably 4 parts by mass or more. The upper limit of the content of the crosslinked polyvinyl chloride resin (B) per 100 parts by mass of the polyvinyl chloride resin (A) is preferably 15 parts by mass or less, more preferably 12 parts by mass or less, and even more preferably 10 parts by mass or less.

[0019] By setting the lower limit of the content of the crosslinked polyvinyl chloride resin (B) within the above range, the glitter of the obtained artificial hair fiber can be suppressed and the feel can be improved. Also, by setting the upper limit of the content of the crosslinked polyvinyl chloride resin (B) within the above range, the glitter of the obtained artificial hair fiber can be suppressed and the feel can be improved, and spinnability can be made sufficient.

[0020] (Indicator obtained by dynamic viscoelasticity measurement) When the dynamic viscoelasticity of the artificial hair fiber of this embodiment is measured under the following conditions, the lower limit of the loss tangent tanδ value X1 at 70°C is 0.060 or more, preferably 0.065 or more, and more preferably 0.70 or more. The upper limit of X1 is 0.120 or less, preferably 0.115 or less, and more preferably 0.110 or less. Furthermore, when the artificial hair fiber of this embodiment is subjected to dynamic viscoelasticity measurement under the following conditions, the loss tangent tan δ has a peak in the temperature range of 90°C or higher and 110°C or lower. By making the loss tangent tanδ have a peak in the temperature range of 90°C or higher and 110°C or lower and by setting the value X1 of the loss tangent tanδ at 70°C within the above range, it is possible to suppress the glitter of the obtained artificial hair fiber and improve the feel. (Dynamic viscoelasticity measurement conditions) The temperature is raised at a rate of 4°C / min, the frequency is 1Hz, and the temperature is measured in the range of 25°C to 170°C by clamping a bundle of 40 artificial hair fibers.

[0021] Furthermore, when the dynamic viscoelasticity of the artificial hair fiber of this embodiment is measured under the above conditions, the lower limit of the loss tangent tanδ value X2 at 60°C is preferably 0.050 or more, more preferably 0.055 or more, and even more preferably 0.060 or more. The upper limit of X2 is preferably 0.100 or less, more preferably 0.095 or less, and even more preferably 0.090 or less. By setting the value X2 of the loss tangent tanδ at 60°C within the above range, the properties of the artificial hair fiber can be stabilized, the glitter of the obtained artificial hair fiber can be further suppressed, and the feel can be further improved.

[0022] Furthermore, it is preferable that the loss tangent tanδ of the artificial hair fiber of this embodiment obtained by the dynamic viscoelasticity measurement described above has a sub-peak in the range of 50° C. or more and less than 80° C. This can further reduce the glitter of the obtained artificial hair fiber and further improve the feel to the touch.

[0023] (additives) The polyvinyl chloride resin composition may contain an antistatic agent, a heat stabilizer, and a lubricant, if necessary.

[0024] (antistatic agent) Antistatic agents that can be used include nonionic (nonionic), cationic, anionic, and amphoteric agents. The content of the antistatic agent is preferably 0.01 to 1 part by mass per 100 parts by mass of the polyvinyl chloride resin (A) and the crosslinked polyvinyl chloride resin (B). By using an antistatic agent content of 0.01 parts by mass or more, static electricity can be prevented. As a result, problems that tend to occur due to static electricity, such as difficulty in gathering yarns and tangling during the winding process, leading to yarn breakage, can be prevented. Furthermore, using an antistatic agent content of 1 part by mass or less can be economically advantageous.

[0025] (heat stabilizer) Conventional heat stabilizers can be used. Among them, it is preferable to use one or more selected from Ca-Zn-based heat stabilizers, hydrotalcite-based heat stabilizers, tin-based heat stabilizers, zeolite-based heat stabilizers, epoxy-based heat stabilizers, and β-diketone-based heat stabilizers. Heat stabilizers are used to prevent thermal decomposition during molding, improve long-run properties, and improve the color tone of the filaments. A combination of a Ca-Zn-based heat stabilizer and a hydrotalcite-based heat stabilizer is particularly preferable, as it provides an excellent balance between molding processability and yarn properties.

[0026] Examples of Ca-Zn-based heat stabilizers include zinc stearate, calcium stearate, zinc 12-hydroxystearate, and calcium 12-hydroxystearate. Examples of hydrotalcite-based heat stabilizers include Alcamizer manufactured by Kyowa Chemical Industry Co., Ltd. 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. Examples of epoxy-based heat stabilizers include epoxidized soybean oil and epoxidized linseed oil. Examples of the β-diketone heat stabilizer include stearoylbenzoylmethane (SBM) and dibenzoylmethane (DBM).

[0027] Specifically, the hydrotalcite-based heat stabilizer is a hydrotalcite compound, such as a complex salt compound composed of magnesium and / or an alkali metal with aluminum or zinc, or a complex salt compound composed of magnesium and aluminum. Furthermore, the hydrotalcite compound may be one from which water of crystallization has been dehydrated. Furthermore, the hydrotalcite compound may be a natural product or a synthetic product, and the synthetic product may be synthesized by a conventionally known method.

[0028] The content of the heat stabilizer is preferably 0.1 to 5.0 parts by mass per 100 parts by mass of the total of the polyvinyl chloride resin (A) and the crosslinked polyvinyl chloride resin (B). By setting the content of the heat stabilizer to 0.1 parts by mass or more, it is possible to prevent the resin composition from yellowing due to thermal degradation. Furthermore, by setting the content of the heat stabilizer to 5.0 parts by mass or less, it is possible to achieve economic advantages.

[0029] (lubricant) As the lubricant, any known lubricant can be used, but at least one selected from the group consisting of metal soap-based lubricants, polyethylene-based lubricants, higher fatty acid-based lubricants, higher alcohol-based lubricants, and ester-based lubricants is particularly preferred. Lubricants can reduce friction with the metal surface of a processing machine and friction between resins, improve fluidity, and improve processability.

[0030] Examples of metal soap-based lubricants include metal soaps such as stearates, laurates, palmitates, and oleates of elements such as Na, Mg, Al, Ca, and Ba. Examples of higher fatty acid-based 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. Examples of higher alcohol-based lubricants include stearyl alcohol, palmityl alcohol, myristyl alcohol, lauryl alcohol, and oleyl alcohol. Examples of ester-based lubricants include ester-based lubricants composed of alcohols and fatty acids, pentaerythritol-based lubricants such as monoesters, diesters, triesters, and tetraesters of pentaerythritol or dipentaerythritol with higher fatty acids, and mixtures thereof, and montanic acid wax-based lubricants such as esters of montanic acid with higher alcohols such as stearyl alcohol, palmityl alcohol, myristyl alcohol, lauryl alcohol, and oleyl alcohol.

[0031] The lubricant content is preferably 0.2 parts by mass or more and 5.0 parts by mass or less per 100 parts by mass of the total of the polyvinyl chloride resin (A) and the cross-linked polyvinyl chloride resin (B). By setting the lubricant content to 0.2 parts by mass or more, it is possible to prevent a decrease in fluidity and suppress a deterioration in processability. Furthermore, by setting the lubricant content to 5.0 parts by mass or less, it is possible to prevent a decrease in friction with the metal surface of the processing machine and to stably extrude the resin.

[0032] In this embodiment, other known compounding agents used in polyvinyl chloride resin compositions can be added depending on the purpose, provided that the effects of the present invention are not impaired. Examples of such compounding agents include processing aids, plasticizers, reinforcing agents, ultraviolet absorbers, antioxidants, fillers, flame retardants, pigments, initial color improvers, conductivity imparting agents, and fragrances.

[0033] (Cross-sectional shape of artificial hair fibers) The artificial hair fiber preferably has a substantially uniform cross-sectional shape along its length. From the viewpoint of further suppressing glare in the resulting artificial hair fiber and further improving the feel, the cross-section of the artificial hair fiber preferably has a shape selected from the group consisting of polygonal, eyeglass-shaped, Y-shaped, and star-shaped. Furthermore, from the viewpoint of reducing the surface area to suppress light reflection and more effectively suppressing glare, the cross-section of the artificial hair fiber more preferably has a shape selected from the group consisting of polygonal, eyeglass-shaped, and Y-shaped. The polygon is preferably a pentagon or an octagon. FIG. 1(a) is a schematic cross-sectional view of an artificial hair fiber 10 having a spectacle-shaped cross section. FIG. 1(b) is a schematic cross-sectional view of an artificial hair fiber 10 having a Y-shaped cross section. As shown in FIG. 1(a), when the cross-sectional shape of the artificial hair fiber 10 is spectacle-shaped, it has two circular or elliptical regions 1 and 2 and a connecting region 3 connecting region 1 and region 2. As shown in FIG. 1(b), the Y-shaped cross section has protrusions 21, 22, and 23 protruding in three directions from a center C. The length L1 of protrusion 21 in the protruding direction (the length from the center C to the tip of protrusion 21), the length L2 of protrusion 22 in the protruding direction (the length from the center C to the tip of protrusion 22), and the length L3 of protrusion 23 in the protruding direction (the length from the center C to the tip of protrusion 23) may be equal, or the length of any one protrusion may be longer than the other two protrusions. The lengths of the three protrusions may also be different from each other. In addition, an artificial hair fiber bundle made up of multiple artificial hair fibers may contain artificial hair fibers with two or more of the cross-sectional shapes described above. From the viewpoint of spinnability, it is preferable that the lengths L1, L2, and L3 are in the range of 50 μm or more and 90 μm or less.

[0034] (Manufacturing method for artificial hair fibers) The artificial hair fibers are preferably produced by mixing all the raw materials, forming a pellet compound, and then subjecting the pellet compound to known melt spinning.

[0035] (Mixing and pellet preparation) Polyvinyl chloride resin (A), crosslinked polyvinyl chloride resin (B), and optionally antistatic agent, heat stabilizer, lubricant, and other compounding ingredients are mixed in predetermined proportions, stirred and mixed in a conventional mixer, and then extruded into a pellet compound (pellet-shaped resin composition). For example, a powder compound (powdered resin composition) obtained by mixing using a conventional mixer such as a Henschel mixer, super mixer, or ribbon blender is melt-mixed to obtain a pellet compound.

[0036] The powder compound may be produced by hot blending or cold blending, and normal production conditions may be used. Preferably, hot blending is used, in which the cutting temperature during blending is increased to 105°C or higher and 155°C or lower, in order to reduce the volatile content in the composition.

[0037] The pellet compound can be produced using a method similar to that used for producing conventional vinyl chloride pellet compounds. For example, pellet compounds can be produced using kneaders such as a single-screw extruder, a counter-rotating twin-screw extruder, a conical twin-screw extruder, a co-rotating twin-screw extruder, a co-kneader, a planetary gear extruder, or a roll mixer. The conditions for producing the pellet compound are not particularly limited, but it is preferable to set the resin temperature to 185°C or less to prevent thermal degradation of the polyvinyl chloride resin composition. A mesh can also be installed near the tip of the screw to remove small amounts of metal chips from the screw or fibers attached to protective gloves that may be mixed into the pellet compound. A cold-cut method can also be used to produce pellets. A means for removing chips (fine particles generated during pellet production) that may be mixed in during cold cutting may also be used. Furthermore, since the cutter blade may chip and generate chips easily after prolonged use, it is recommended that it be replaced as needed.

[0038] (spinning) The pellets obtained as described above are melt-spun by extruding the resin through a nozzle with projections on three sides under conditions that favor spinnability, with a cylinder temperature of 150° C. to 190° C. and a nozzle temperature of 180±15° C. The cross-sectional shape of the nozzle is set so that the cross section of the resulting artificial hair fiber has the desired shape.

[0039] The undrawn yarn (fiber of polyvinyl chloride resin composition) melt-spun from the nozzle is introduced into a heating cylinder (heating cylinder temperature: 250°C) and instantaneously heat-treated, and then taken up by a take-up machine installed approximately 4.5 m directly below the nozzle. The strand remains undrawn. During this winding, the take-up speed is adjusted so that the fineness of the undrawn yarn is 175 denier or more and 185 denier or less.

[0040] A conventionally known extruder can be used to form the polyvinyl chloride resin composition into an undrawn thread. For example, a single-screw extruder, a counter-rotating twin-screw extruder, or a conical twin-screw extruder can be used. It is particularly preferable to use a single-screw extruder with a nozzle diameter of 35 mm to 85 mm or a conical extruder with a nozzle diameter of 35 mm to 50 mm. If the nozzle diameter is too large, the extrusion rate will be high and the nozzle pressure will be too high, which may increase the resin temperature and lead to deterioration.

[0041] (Stretching and Heat Treatment) Next, the undrawn yarn is drawn 3 times in a drawing machine (for example, at 105°C in an air atmosphere), and then heat-treated using a heat treatment machine (for example, at 120°C in an air atmosphere) to draw the yarn to, for example, 0.75 times (the fiber is heat-shrunk until the entire length is 75% of the length before treatment), so that the fineness is 58 denier or more and 62 denier or less, and artificial hair fiber is produced.

[0042] (Gear processing) The artificial hair fiber may be gear-processed as needed. Gear processing is a method of crimping a fiber bundle by passing it between two meshing, high-temperature gears. The material of the gears used, the shape of the gear waves, and the number of gears are not particularly limited. The crimp wave shape can vary depending on the fiber material, fineness, and pressure conditions between the gears. In this embodiment, the crimp wave shape can be controlled by the depth of the gear wave grooves, the gear surface temperature, and the processing speed. There are no particular restrictions on these processing conditions, but preferably, the depth of the gear wave grooves is 0.2 mm to 6 mm, more preferably 0.5 mm to 5 mm, the gear surface temperature is 30°C to 100°C, more preferably 40°C to 80°C, and the processing speed is 0.5 m / min to 10 m / min, more preferably 1.0 m / min to 8.0 m / min.

[0043] The total fineness of the fiber bundles used in gear processing is not particularly limited, but is preferably 100,000 decitex or more and 2,000,000 decitex or less, more preferably 500,000 decitex or more and 1,500,000 decitex or less. By setting the total fineness of the fiber bundles to 100,000 decitex or more, the productivity of gear processing can be increased and yarn breakage during gear crimp processing can be suppressed. On the other hand, by setting the total fineness of the fiber bundles to 2,000,000 decitex or less, a more uniform wave shape can be obtained.

[0044] The artificial hair fiber according to the embodiment described above can exhibit a good balance between a good feel and an appearance with reduced glare.

[0045] In this embodiment, artificial hair fibers that satisfy the above-mentioned parameters can be obtained by appropriately adjusting the types and blending ratios of each component contained in the artificial hair fiber and the preparation method of the polyvinyl chloride resin (A) and the cross-linked polyvinyl chloride resin (B). In addition, the above-mentioned parameters can be satisfied by selecting the cross-sectional shape of the artificial hair fiber from the shapes described above.

[0046] (head accessories) The artificial hair fiber according to the embodiment can be used for head ornaments. Examples of the head ornaments include wigs, hair pieces, braids, and hair extensions. The head ornaments obtained from the artificial hair fiber according to the embodiment exhibit effects similar to those of human hair.

[0047] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations can also be adopted. Below, examples of reference forms are given. 1. An artificial hair fiber formed from a polyvinyl chloride resin composition, When dynamic viscoelasticity measurements were performed under the following conditions, The value X1 of the loss tangent tanδ at 70 ° C is 0.06 or more and 0.12 or less, Artificial hair fiber with a peak temperature range of 90℃ to 110℃. (Dynamic viscoelasticity measurement conditions) The temperature rise rate is 4°C / min, the frequency is 1Hz, and a bundle of 40 artificial hair fibers is sandwiched between the fibers. 2. The artificial hair fiber according to 1, wherein the value X2 of the loss tangent tanδ at 60°C obtained by the dynamic viscoelasticity measurement is 0.05 or more and 0.10 or less. 3. The artificial hair fiber according to 1. or 2., wherein the cross section of the artificial hair fiber has a shape selected from the group consisting of a polygon, a glasses-shaped, and a Y-shaped. 4. The polyvinyl chloride resin composition contains a non-crosslinked polyvinyl chloride resin and a crosslinked polyvinyl chloride resin, The fiber for artificial hair according to any one of 1. to 3., wherein the content of the cross-linked polyvinyl chloride resin per 100 parts by mass of the non-cross-linked polyvinyl chloride resin is 2 parts by mass or more and 15 parts by mass or less. 5. The artificial hair fiber according to 4, wherein the viscosity-average degree of polymerization of the non-crosslinked polyvinyl chloride resin is 450 or more and 1700 or less. 6. Artificial hair fiber according to 4. or 5., wherein the crosslinked polyvinyl chloride resin has a viscosity-average degree of polymerization of a component that dissolves in tetrahydrofuran of 500 or more and 2,300 or less. 7. A head ornament using the artificial hair fiber described in any one of 1. to 6. [Example]

[0048] EXAMPLES The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these.

[0049] Table 1 shows the ingredients and amounts used to prepare the artificial hair fibers of each Example and Comparative Example. The details of the components shown in Table 1 are as follows: Vinyl chloride resin: vinyl chloride homopolymer, viscosity average polymerization degree 500 (manufactured by Taiyo Vinyl Corporation, TH-1000) The viscosity average degree of polymerization was calculated according to JIS-K6721 by dissolving 200 mg of vinyl chloride in 50 mL of nitrobenzene, measuring the specific viscosity of this polymer solution using an Ubbelohde viscometer in a thermostatic bath at 30°C. Cross-linked polyvinyl chloride resin: Partially cross-linked polyvinyl chloride resin, THF-soluble content, viscosity average degree of polymerization 1600 (Shin-Etsu Chemical Co., Ltd., GR-1300T) The viscosity-average degree of polymerization of the tetrahydrofuran (THF)-soluble fraction was measured as follows. 1 g of crosslinked polyvinyl chloride resin was added to 60 mL of tetrahydrofuran and allowed to stand for approximately 24 hours. The resin was then dissolved using an ultrasonic cleaner. The insoluble fraction in the THF solution was separated using an ultracentrifuge (30,000 rpm x 1 hour), and the supernatant THF solvent was collected. The THF solvent was then evaporated, and the viscosity-average degree of polymerization was measured in the same manner as for the polyvinyl chloride resin (A) described above. Antistatic agent: NOF Corporation's New Elegant ASK Heat stabilizer: Nissan Chemical Industries, Ltd., CP-410A Lubricant: Riken Vitamin Co., Ltd., EW-100

[0050] Example 1 The vinyl chloride resin compositions according to the ingredients and blending amounts shown in Table 1 were mixed in a ribbon blender, and the mixture was melt-kneaded using an extruder with a diameter of 40 mm at a cylinder temperature in the range of 130°C to 170°C to prepare pellets. The pellets were melt-spun in a 30 mm diameter extruder with a nozzle having 120 eyeglass-shaped holes at a cylinder temperature of 140°C to 190°C and a nozzle temperature of 180±15°C at an extrusion rate of 10 kg / h. The melt-spun fibers were then heat-treated for 0.5 to 1.5 seconds in a heating cylinder (in an atmosphere of 200 to 300°C) placed directly below the nozzle to produce 150 dtex fibers. The melt-spun fibers were then stretched 300% in an air atmosphere at 100°C, and then heat-shrunk in an air atmosphere at 120°C until the entire length of the fibers was 75% of the length before treatment, yielding 67 dtex artificial hair fibers of Example 1.

[0051] (Examples 2, 3 and 6, Comparative Examples 1 and 2) Artificial hair fibers of Examples 2, 3 and 6 and Comparative Examples 1 and 2 were produced in the same manner as in Example 1, except that vinyl chloride resin compositions having the components and blending amounts shown in Table 1 were used.

[0052] Example 4 The artificial hair fiber of Example 4 was produced in the same manner as in Example 1, except that the vinyl chloride resin composition having the components and amounts shown in Table 1 was used and melt-spinning was carried out using an extruder with pentagonal holes.

[0053] Example 5 The artificial hair fiber of Example 5 was produced in the same manner as in Example 1, except that the vinyl chloride resin composition having the components and amounts shown in Table 1 was used and melt-spinning was carried out using an extruder with a Y-shaped hole.

[0054] Example 7 The artificial hair fiber of Example 7 was produced in the same manner as in Example 1, except that the vinyl chloride resin composition having the components and amounts shown in Table 1 was used and melt-spinning was carried out using an extruder with star-shaped holes.

[0055] (Cross-sectional shape observation) The cross sections of the obtained artificial hair fibers were observed using a digital microscope, VHX-500, manufactured by Keyence Corporation, and the cross-sectional shapes of the artificial hair fibers were classified. The observation results of the cross-sectional shapes of each artificial hair fiber are shown in Table 1.

[0056] (Dynamic viscoelasticity measurement conditions) Using a DMS6100 manufactured by SII Nano Technology, Inc., a bundle of 40 artificial hair fibers was clamped at a heating rate of 4°C / min, a frequency of 1Hz, and a chuck distance of 3mm, and the loss tangent tanδ was measured in the range of 25°C to 170°C. The values ​​of the loss tangent tanδ at 60°C and 70°C were obtained, and the presence or absence of a peak in the loss tangent tanδ in the range of 90°C to 110°C was also investigated. The results are shown in Table 1.

[0057] (Tactile sensation) A bundle of approximately 20,000 artificial hair fibers was gently held and evaluated for softness, flexibility, and appropriate elasticity (touch), as well as the ease of running fingers through the bundle (smoothness). Specifically, five artificial hair fiber processing technicians evaluated and judged the bundle according to the following criteria. Evaluation criteria More than 90% of the technicians who rated the product as being very smooth and having a particularly good feel were given a "○", while 70% to 90% of the technicians who rated the product as being slightly less smooth but having a good feel were given a "△", and less than 70% of the technicians who rated the product as not smooth and having a bad feel were given an "×". The evaluation results are shown in Table 1.

[0058] (glare) A bundle of approximately 20,000 artificial hair fibers was exposed to light (sunlight) and evaluated for excessive glare from bright spots caused by the reflection of light. Five artificial hair fiber processing technicians evaluated and judged the fibers according to the following criteria. Evaluation criteria More than 90% of the technicians who rated the product as having no glare, a natural gloss, and a particularly good appearance rated it as "○", while 70% to 90% of the technicians who rated the product as having a certain amount of glare but not enough to bother them rated it as "△", and less than 70% of the technicians who rated the glare as being too strong, unnatural, and visually unpleasant rated it as "×". The evaluation results for glare are shown in Table 1. [Table 1]

[0059] As shown in Table 1, it was confirmed that the artificial hair fibers of Examples 1 to 7 exhibited a good feel and a good appearance with reduced glitter. Among these, the artificial hair fibers of Examples 1, 4, and 5 showed particularly good results in both feel and glitter. In contrast, Comparative Example 1 had poor glare, and Comparative Example 2 had poor tactile feel.

[0060] This application claims priority based on Japanese Patent Application No. 2018-224036, filed November 29, 2018, the disclosure of which is incorporated herein by reference in its entirety.

Claims

1. An artificial hair fiber formed from a polyvinyl chloride resin composition, the polyvinyl chloride resin composition contains a non-crosslinked polyvinyl chloride resin and a crosslinked polyvinyl chloride resin, and the content of the crosslinked polyvinyl chloride resin per 100 parts by mass of the non-crosslinked polyvinyl chloride resin is 2 parts by mass or more and 10 parts by mass or less; In the crosslinked polyvinyl chloride resin, the viscosity-average degree of polymerization of a component soluble in tetrahydrofuran is 500 or more and 1600 or less, The cross section of the artificial hair fiber has a shape selected from the group consisting of a polygon, a glasses shape, and a Y shape, When dynamic viscoelasticity measurements were performed under the following conditions, The value X1 of the loss tangent tanδ at 70 ° C is 0.06 or more and 0.12 or less, Artificial hair fibers having a peak temperature in the range of 90°C or higher and 110°C or lower. (Dynamic viscoelasticity measurement conditions) The temperature is raised at a rate of 4° C. / min and at a frequency of 1 Hz, and a bundle of 40 artificial hair fibers is sandwiched between the fibers.

2. 2. The artificial hair fiber according to claim 1, wherein the value X2 of loss tangent tanδ at 60° C. obtained by the dynamic viscoelasticity measurement is 0.05 or more and 0.10 or less.

3. 3. The artificial hair fiber according to claim 1, wherein the viscosity average degree of polymerization of said non-crosslinked polyvinyl chloride resin is 450 or more and 1,700 or less.

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