Artificial hair fiber and hair ornament product

Abstract

The present invention addresses the problem of providing artificial hair fibers having a reduced glossiness.　One embodiment of the present invention pertains to artificial hair fibers that are each provided with a plurality of hollow parts extending in the longitudinal direction. Preferably, a first hollow part among the plurality of hollow parts is present substantially at the center in a fiber cross section perpendicular to the longitudinal direction of each of the artificial hair fibers, and one or more second hollow parts among the plurality of hollow parts are each present, in said fiber cross section, closer to the outer edge of the corresponding one of the artificial hair fibers with as compared to the first hollow part.

Description

Artificial hair fibers and hair accessories

[0001] The present invention relates to an artificial hair fiber and a hair accessory product.

[0002] Artificial hair is becoming increasingly important as an alternative to human hair in head accessories such as wigs, hairpieces, hair extensions, hair bands, doll hair, etc. Materials for artificial hair fibers include acrylic resins, vinyl chloride resins, and polyester resins, and artificial hair fibers made from these resins are commercially available.

[0003] Patent Document 1 discloses artificial hair containing hollow fibers having hollow portions with a hollow ratio of 10 to 50%. Patent Document 2 discloses fibers for artificial hair having a void in the center of the fiber cross section, the ratio of the area of ​​the void to the total area of ​​the fiber cross section being 5% to 50%, the cross-sectional shape of the fiber cross section being flattened multi-lobed, and the void having first and second sides inclined at an angle of 70 to 110 degrees with respect to the major axis of the fiber cross section.

[0004] JP 2008-285772 A

[0005] In recent years, there has been a demand for lightweight artificial hair fibers, and for example, Patent Documents 1 and 2 disclose artificial hair fibers having hollow portions. However, conventional artificial hair fibers have a high glossiness, which gives them an artificial sheen, making it difficult to achieve a natural appearance similar to that of human hair.

[0006] The present invention has been made in view of the above circumstances, and provides a fiber for artificial hair with reduced glossiness.

[0007] As a result of extensive research, the present inventors have found that the above problems can be solved by providing a specific hollow structure in artificial hair fibers, and have thus completed the present invention.

[0008] According to the present invention, the following are provided: [1] An artificial hair fiber comprising a plurality of hollow portions extending in the longitudinal direction. [2] The artificial hair fiber according to [1], wherein a first hollow portion of the plurality of hollow portions is located approximately at the center of a fiber cross section perpendicular to the longitudinal direction of the artificial hair fiber, and one or more second hollow portions of the plurality of hollow portions are located further toward the outer edge of the artificial hair fiber than the first hollow portion in the fiber cross section. [3] The artificial hair fiber according to [1], wherein the largest hollow portion of the plurality of hollow portions occupies 5% to 50% of the area of ​​the fiber cross section perpendicular to the longitudinal direction, and the remaining one or more hollow portions occupy, on average, 0.1% to 4% of the area of ​​the fiber cross section. [4] The artificial hair fiber according to [3], wherein the largest hollow portion is located at the approximate center of the cross section of the artificial hair fiber perpendicular to the longitudinal direction, and the other one or more hollow portions are located in the direction of the outer edge of the artificial hair fiber from the largest hollow portion in the cross section of the fiber. [5] The area of ​​the largest hollow portion among the plurality of hollow portions in the cross section of the fiber perpendicular to the longitudinal direction is S Ｍ The total area of ​​one or more other hollow portions in the fiber cross section is S Ｏ When this is done, S Ｍ / S Ｏ [6] The length of the outer edge of the largest hollow portion among the plurality of hollow portions in the fiber cross section perpendicular to the longitudinal direction is L Ｍ The total length of the outer edge of one or more other hollow portions in the fiber cross section is L Ｏ When this is done, L Ｍ / L ＯThe fiber for artificial hair according to any one of [1] to [5], wherein the tensile strength of the fiber is 1.3 to 3.8. [7] The fiber for artificial hair according to any one of [1] to [6], wherein the shortest distance between the outer edges of adjacent hollow portions among the plurality of hollow portions is 3 μm to 30 μm. [8] The fiber for artificial hair according to any one of [2] to [7], wherein the cross section of the fiber comprises at least one of an inner protrusion protruding from one or more of the plurality of hollow portions toward one of the plurality of hollow portions from the other hollow portions, and an outer protrusion protruding from one or more of the plurality of hollow portions toward the outer edge of the fiber for artificial hair. [9] The fiber for artificial hair according to any one of [1] to [8], wherein the number of the plurality of hollow portions is three or more.

[10] The fiber for artificial hair according to any one of [1] to [9], which contains a vinyl chloride resin.

[11] A hair accessory product comprising the fiber for artificial hair according to any one of [1] to

[10] .

[12] The hair accessory product according to

[11] , which includes a braid.

[0009] According to the present invention, it is possible to provide a fiber for artificial hair with reduced glossiness.

[0010] Fig. 1 is a cross-sectional view showing a fiber cross-section perpendicular to the longitudinal direction of an artificial hair fiber according to a first embodiment. Fig. 2 is a cross-sectional view showing a fiber cross-section perpendicular to the longitudinal direction of an artificial hair fiber according to one embodiment of the present invention. The cross-sectional shapes of the artificial hair fibers are as follows: Fig. 2A is a bilobal shape with two C-shaped portions joined together; Fig. 2B is a trilobal shape with three C-shaped portions joined together; Fig. 2C is a substantially triangular shape; and Fig. 2D is a substantially rectangular shape. Fig. 3 is a cross-sectional view showing a fiber cross-section perpendicular to the longitudinal direction of an artificial hair fiber according to one embodiment of the present invention. Fig. 3A shows an artificial hair fiber without either inner or outer protrusions, Fig. 3B shows an artificial hair fiber with only outer protrusions, and Fig. 3C shows an artificial hair fiber with both inner and outer protrusions. Fig. 4 is an enlarged photograph of the fiber cross-section of an artificial hair fiber according to one example.

[0011] The present invention will be described in detail below. However, the present invention is not limited to these descriptions. The features of the following embodiments can be combined with each other. Furthermore, each feature can be an invention independently.

[0012] <Explanation of Terms> In this specification, for example, the expression "X to Y" means that X or more and Y or less.

[0013] 1. Artificial Hair Fiber 1.1 Shape of Artificial Hair Fiber Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this specification and drawings, components with the same reference numerals have substantially the same structure or function. In addition, the drawings may be drawn to a different scale from the actual scale to facilitate understanding.

[0014] 1.1.1 First embodiment Figure 1 is a cross-sectional view showing a fiber cross section perpendicular to the longitudinal direction of an artificial hair fiber 10 according to this embodiment (hereinafter simply referred to as "fiber cross section"). As shown in Figure 1, the artificial hair fiber 10 according to this embodiment comprises four hollow portions 20 (one 20A and three 20B) extending in the longitudinal direction. More specifically, the artificial hair fiber 10 comprises a hollow portion 20A and a solid portion 30 covering it. Furthermore, the solid portion 30 comprises three hollow portions 20B. In this specification, a "hollow portion" can be defined as a portion that exists continuously for 10 cm or more in the longitudinal direction of the artificial hair fiber 10 and has a major diameter of 3 µm or more in the fiber cross section. The artificial hair fiber 10 of this embodiment is lightweight because it has a hollow portion 20, and offers many advantages, such as being able to create the desired voluminous hairstyle with a small amount of wear, being able to achieve a wide range of hairstyles including heavy long styles, being able to reduce damage to one's own hair and scalp, and being able to reduce waste and environmental impact.

[0015] 1, the hollow section 20 according to this embodiment is such that the hollow section 20A is located approximately at the center of the fiber cross section, and the other hollow sections 20B are located from the hollow section 20A toward the outer edge 11 of the artificial hair fiber 10 in the fiber cross section (hereinafter, the hollow section 20 located approximately at the center of the fiber cross section will be referred to as the "first hollow section," and the hollow section 20 located more toward the outer edge of the fiber cross section will be referred to as the "second hollow section"). Here, "a hollow section located approximately at the center of the fiber cross section" means that the center of the fiber cross section is within the hollow section. By arranging the hollow sections 20 of the artificial hair fiber 10 in this manner, the gloss of the artificial hair fiber bundle is reduced, resulting in a natural appearance.

[0016] The outer edge shape of the fiber cross section of the artificial hair fiber 10 according to this embodiment is circular, but is not particularly limited to this. Figures 2 and 3 show examples of fiber cross sections of the artificial hair fiber 10 according to one aspect of the present invention. The outer edge shape of the fiber cross section can be any one selected from a circular shape ( Figures 1 and 3A ), an elliptical shape, an approximately circular shape ( Figures 3B and 3C ), a bilobal shape formed by joining two C-shaped shapes ( Figure 2A ), a trilobal shape formed by joining three C-shaped shapes ( Figure 2B ), a multilobal shape formed by joining four or more C-shaped shapes, an approximately triangular shape ( Figure 2C ), an approximately rectangular shape ( Figure 2D ), and an approximately polygonal shape.

[0017] The artificial hair fiber 10 according to this embodiment has a major diameter M １ is preferably 30 to 300 μm, and more preferably 50 to 150 μm. １ The major axis M of the cross section of the fiber for artificial hair 10 may be, for example, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, or 300 μm, or may be within a range between any two of the values ​​exemplified here. １ When the content of the fiber bundle for artificial hair is within this range, the texture of the fiber bundle for artificial hair is improved and the appearance is natural.

[0018] In the present embodiment, the shape of the hollow portion 20A in the cross section of the fiber is substantially circular, and the shape of the hollow portion 20B is also circular, but the shape of the hollow portion 20 in the cross section of the fiber is not particularly limited. The shape of the hollow portion 20 in the cross section of the fiber can be any one selected from a circular shape (hollow portion 20B in FIGS. 1 to 3 , hollow portion 20A in FIG. 3A and hollow portion 20A in FIG. 3B ), a substantially circular shape (hollow portion 20A in FIG. 1 and hollow portion 20A in FIG. 3C ), an elliptical shape and a substantially elliptical shape, a bilobal shape (hollow portion 20A in FIG. 2A ), a trilobal shape (hollow portion 20A in FIG. 2B ), a multilobal shape, a substantially triangular shape (hollow portion 20A in FIG. 2C ), a substantially quadrangular shape (hollow portion 20A in FIG. 2D ), and a substantially polygonal shape. Of the hollow portions 20, one or more hollow portions 20 other than the largest hollow portion (in this embodiment, hollow portion 20B) preferably have an elongated, approximately elliptical or elongated, approximately polygonal shape in the fiber cross section.

[0019] Among the hollow portions 20 according to this embodiment, the largest hollow portion (hollow portion 20A in this embodiment) has a major diameter M ２ is preferably 10 to 200 μm, and more preferably 20 to 100 μm. ２ The major axis M of the fiber cross section of the largest hollow portion may be, for example, 10, 11, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, or 200 μm, or may be within a range between any two of the values ​​exemplified here. ２ When the thickness is within this range, the artificial hair fiber bundle is excellent in lightness and can ensure sufficient structure retention.

[0020] Among the hollow portions 20 according to this embodiment, one or more hollow portions other than the largest hollow portion (in this embodiment, hollow portion 20B) have a major diameter M in the fiber cross section. ３ The major axis M of one or more hollow portions other than the largest hollow portion (hollow portion 20B in this embodiment) in the fiber cross section is preferably 3 to 30 μm, and more preferably 5 to 15 μm. ３The major axis M of one or more hollow portions other than the largest hollow portion in the fiber cross section may be, for example, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30 μm, or may be within a range between any two of the values ​​exemplified here. ３ When the content is within this range, the artificial hair fiber bundle can be guaranteed to have a sufficient structural retention, and the glossiness is reduced, resulting in a natural appearance.

[0021] Of the hollow portions 20 according to this embodiment, the largest hollow portion (hollow portion 20A in this embodiment) preferably occupies 5 to 50% of the area of ​​the fiber cross section. The largest hollow portion may occupy, for example, 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50% of the area of ​​the fiber cross section, or may be within a range between any two of the numerical values ​​exemplified here. When the area ratio of the largest hollow portion in the fiber cross section is within this range, the artificial hair fiber bundle is lightweight and can ensure sufficient structural retention. The area ratio of the hollow portion 20 in the fiber cross section can be calculated using the following formula: (Area ratio of hollow portions 20 in fiber cross section) = {(Area surrounded by outer edge 21 of hollow portions 20) / (Area surrounded by outer edge 11 of artificial hair fiber 10)} x 100 The area surrounded by outer edge 11 of artificial hair fiber 10 means the cross-sectional area when it is assumed that artificial hair fiber 10 does not have hollow portions 20. The area ratio of hollow portions 20 in fiber cross section can be determined by cutting artificial hair fiber 10 perpendicular to the longitudinal direction, observing the cut surface with a laser microscope or scanning electron microscope, etc., and performing image analysis; specifically, it can be determined by the method described in the examples.

[0022] Of the hollow portions 20 according to this embodiment, one or more hollow portions other than the largest hollow portion (hollow portion 20B in this embodiment) preferably occupy, on average, 0.1 to 4% of the area of ​​the fiber cross section. The one or more hollow portions other than the largest hollow portion may, on average, occupy, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, or 4% of the area of ​​the fiber cross section, or may be within a range between any two of the numerical values ​​exemplified here. When one or more hollow portions other than the largest hollow portion occupy such an area in the fiber cross section, the gloss of the artificial hair fiber bundle is reduced, resulting in a more natural appearance.

[0023] In this embodiment, the hollow portion 20A is the largest hollow portion and is located approximately at the center in the fiber cross section. The hollow portions 20B are each a hollow portion other than the largest hollow portion and are located in the direction of the outer edge 11 of the artificial hair fiber 10 from the hollow portion 20A in the fiber cross section. Thus, it is preferable that the largest hollow portion of the hollow portions 20 is the first hollow portion and that one or more hollow portions other than the largest hollow portion are the second hollow portions. Such a hollow portion 20 structure can maintain its structure even when subjected to gear processing, etc.

[0024] Among the hollow portions 20 according to this embodiment, the area of ​​the largest hollow portion (hollow portion 20A in this embodiment) in the fiber cross section is S Ｍ The total area of ​​one or more other hollow portions (in this embodiment, the hollow portion 20B) in the fiber cross section is S Ｏ When this is done, S Ｍ / S Ｏ is preferably 5 to 40. Ｍ and S Ｏ are respectively replaced with the total area ratio of the largest hollow portion in the fiber cross section and the area ratio of one or more other hollow portions in the fiber cross section, to obtain S Ｍ / S Ｏ may be calculated. Ｍ / S Ｏ For example, S may be 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, or 40, or may be within a range between any two of the values ​​exemplified herein.Ｍ / S Ｏ When the value of is within this range, the artificial hair fiber 10 has excellent structure retention, and the glossiness of the artificial hair fiber bundle is reduced, resulting in a natural appearance.

[0025] The length of the outer edge 21 of the largest hollow portion (hollow portion 20A in this embodiment) in the fiber cross section among the hollow portions 20 according to this embodiment is L Ｍ The total length of the outer edge 21 of one or more other hollow portions (in this embodiment, the hollow portion 20B) in the fiber cross section is set to L Ｏ When this is done, L Ｍ / L Ｏ is preferably 1.3 to 3.8. Ｍ / L Ｏ L may be, for example, 1.3, 1.4, 1.6, 1.8, 2.0, 2.2, 2.4, 2.6, 2.8, 3.0, 3.2, 3.4, 3.6, or 3.8, or may be within a range between any two of the values ​​exemplified herein. Ｍ / L Ｏ When the value of is such, the artificial hair fiber 10 has excellent structure retention, and the glossiness of the artificial hair fiber bundle is reduced, resulting in a natural appearance. The length of the outer edge 21 of the hollow portion 20 in the fiber cross section can be determined by cutting the artificial hair fiber 10 perpendicular to the longitudinal direction, observing the cut surface with a laser microscope or scanning electron microscope, and performing image analysis, and specifically, it can be determined by the method described in the examples.

[0026] In this embodiment, the shortest distance D between the outer edges 21 of adjacent hollow sections 20 is preferably 3 to 30 μm. The shortest distance D may be, for example, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30 μm, or may be within a range between any two of the values ​​exemplified here. When the lower limit of the shortest distance D is within this range, the artificial hair fiber 10 has excellent structural retention. Furthermore, when the upper limit of the shortest distance D is within this range, the artificial hair fiber 10 has excellent lightness. The shortest distance D between the outer edges 21 of the hollow sections 20 can be determined by cutting the artificial hair fiber 10 perpendicular to the longitudinal direction, observing the cut surface with a laser microscope or scanning electron microscope, and performing image analysis. Specifically, it can be determined by the method described in the examples.

[0027] The artificial hair fiber 10 according to this embodiment further comprises, in the fiber cross section, inner protrusions 22 that protrude from one of the plurality of hollow portions 20B toward one hollow portion 20A among the plurality of hollow portions 20. In this manner, it is preferable that an inner protrusion 22 is provided that protrudes from one or more of the remaining hollow portions 20 toward one of the plurality of hollow portions 20. FIG. 3 is a cross-sectional view showing a fiber cross section perpendicular to the longitudinal direction of an artificial hair fiber 10 according to another embodiment. As shown in FIG. 3A, an embodiment that does not comprise either the inner protrusions 22 or the outer protrusions 24 described below is also an aspect of the present application. On the other hand, as shown in FIG. 3B, the artificial hair fiber 10 according to another embodiment comprises, in the fiber cross section, outer protrusions 24 that protrude from multiple hollow portions 20B among the plurality of hollow portions 20 toward the outer edge 11 of the artificial hair fiber 10. 3C, an artificial hair fiber 10 according to another embodiment has, in the fiber cross section, inner protrusions 22 that protrude from one hollow portion 20A out of the plurality of hollow portions 20 from the remaining hollow portions 20B, and outer protrusions 24 that protrude from a plurality of hollow portions 20B out of the plurality of hollow portions 20 toward the outer edge 11 of the artificial hair fiber 10. Thus, in the fiber cross section, it is preferable that outer protrusions 24 are provided that protrude from one or more of the plurality of hollow portions 20 toward the outer edge 11 of the artificial hair fiber 10. It is preferable that the fiber cross section has at least one of the inner protrusions 22 and the outer protrusions 24. With this structure, the artificial hair fiber 10 has excellent structure retention. Furthermore, from the viewpoint of improving the feel of the artificial hair fiber 10, it is preferable that the outer protrusions 24 are small in size and frequency, and it is preferable that the outer protrusions 24 are smaller or less frequent than the inner protrusions 22, and it is even more preferable that only the inner protrusions 22 are provided.

[0028] Although the number of hollow sections 20 in this embodiment is four, there is no particular limitation as long as it is two or more. The number of hollow sections 20 may be 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15, and may be within a range between any two of the numerical values ​​exemplified here. When the lower limit of the number of hollow sections 20 is such a value, the glossiness of the fiber bundle for artificial hair is reduced, resulting in a natural appearance. When the upper limit of the number of hollow sections 20 is such a value, the fiber for artificial hair 10 has excellent structure retention.

[0029] Next, modified examples of the artificial hair fiber 10 of the above-described embodiment will be described. In the artificial hair fiber 10 according to this embodiment, the multiple hollow portions 20 extending in the longitudinal direction may all have the same size (long diameter, area occupied in the fiber cross section). In this case, any one of the "largest hollow portions" can be selected. Furthermore, in the artificial hair fiber 10 according to this embodiment, the largest hollow portion among the hollow portions 20 extending in the longitudinal direction may not be located approximately in the center. Such an artificial hair fiber 10 also constitutes one embodiment of the present invention.

[0030] 1.2 Composition The resin composition constituting the artificial hair fiber 10 according to this embodiment is not particularly limited, and may contain at least one of polyamide-based resin, polyester-based resin, vinyl chloride-based resin, AS-based resin (acrylonitrile styrene-based resin), PP resin, PET resin, PE resin, PAN-based resin, and PLA-based resin (polylactic acid-based resin). From the viewpoint of easily achieving the die swelling effect described below, the artificial hair fiber 10 according to this embodiment preferably contains a vinyl chloride-based resin. Furthermore, the artificial hair fiber 10 according to this embodiment preferably contains a vinyl chloride-based resin and an AS-based resin.

[0031] The polyvinyl chloride resin according to the present embodiment may comprise a vinyl chloride polymer containing monomer units (vinyl chloride monomer units) derived from vinyl chloride monomer. The polyvinyl chloride resin according to the present embodiment may comprise a homopolymer obtained by homopolymerizing vinyl chloride monomer, and / or a copolymer containing monomer units derived from vinyl chloride monomer and another monomer copolymerizable with vinyl chloride monomer. Examples of copolymers include copolymers of vinyl chloride and vinyl esters, such as vinyl chloride-vinyl acetate copolymer and vinyl chloride-vinyl propionate copolymer; copolymers of vinyl chloride and olefins, such as vinyl chloride-ethylene copolymer and vinyl chloride-propylene copolymer; and vinyl chloride-acrylonitrile copolymer. Furthermore, the polyvinyl chloride resin according to the present embodiment may comprise one type of vinyl chloride polymer, or may comprise two or more types of vinyl chloride polymers.

[0032] The resin composition constituting the artificial hair fiber 10 according to this embodiment contains 50 to 99% by mass, preferably 65 to 95% by mass, and more preferably 65 to 90% by mass of vinyl chloride resin per 100% by mass of the resin composition. Specifically, the content is, for example, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 99% by mass, and may be within a range between any two of the values ​​exemplified here.

[0033] The AS resin (acrylonitrile-styrene-based resin) is a copolymer containing styrene-based monomer units and acrylonitrile-based monomer units, and may contain other monomer units copolymerizable therewith, as necessary. The AS resin may contain, for example, 60, 65, 70, 75, 80, 85, or 90% by mass of styrene-based monomer units relative to 100% by mass of the AS resin, or may be within a range between any two of the values ​​exemplified herein. The AS resin may contain, for example, 10, 15, 20, 25, 30, 35, or 40% by mass of acrylonitrile-based monomer units relative to 100% by mass of the AS resin, or may be within a range between any two of the values ​​exemplified herein.

[0034] The artificial hair fiber 10 according to this embodiment may contain other components as needed, such as antistatic agents, heat stabilizers, lubricants, colorants, processing aids, plasticizers, strengthening agents, UV absorbers, antioxidants, fillers, flame retardants, pigments, initial color improvers, conductivity imparting agents, and fragrances.

[0035] 1.3 Manufacturing Method of Artificial Hair Fiber The manufacturing method of the artificial hair fiber 10 according to this embodiment includes a step of preparing a resin composition for artificial hair fiber and a spinning step, and may further include a drawing step, a heat treatment step, and a gear processing step.

[0036] 1.3.1 Preparation of Resin Composition for Artificial Hair Fiber In the preparation of a resin composition for artificial hair fiber, raw materials containing resins are mixed to obtain a resin composition for artificial hair fiber. Here, the raw materials include a base resin and may contain other components as necessary.

[0037] The mixing method is not particularly limited, and conventionally known methods can be employed. For example, a powdered resin composition (powder compound) can be obtained using known mixing devices such as a Henschel mixer, super mixer, or ribbon blender, and the powder compound can then be melt-mixed to obtain a pellet-shaped resin composition (pellet compound). The powder compound can be produced by either hot blending or cold blending. For example, to reduce volatiles from the resin composition, hot blending can be performed at a cut temperature of 105 to 155°C during mixing. The pellet compound can be produced by a method similar to that used to produce pellet compounds of general polyvinyl chloride resins. 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 kneader. 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 resin composition. A mesh can also be installed near the tip of the screw to remove small amounts of metal chips from the screw and fibers from protective gloves that may be mixed into the pellet compound. The cold-cut method can be used to produce pellets. A means of removing chips (fine particles generated during pellet production) that may be mixed in during cold cutting can also be used. Since the cutter blades can chip and generate chips easily after prolonged use, it is recommended to replace them as needed.

[0038] 1.3.2 Spinning Process In the spinning process, the resin composition for artificial hair fibers is melt-spun to obtain artificial hair fibers 10. As an example, the resin composition (e.g., pellet compound) can be extruded from a heated cylinder through a nozzle to melt-spin. Any conventionally known extruder can be used, such as a single-screw extruder, a counter-rotating twin-screw extruder, or a conical twin-screw extruder.

[0039] The melt spinning conditions can be appropriately set depending on the type of resin composition so that the resin melts and the hollow portion 20B is formed. As an example, the cylinder temperature can be set to 150 to 190°C, and the nozzle temperature can be set to 155 to 195°C. The extrusion rate is preferably 5 to 20 kg / h, and more preferably 8 to 18 kg / h. When the temperature and extrusion rate are within these ranges, the hollow portion 20B is easily formed and has a suitable size.

[0040] The undrawn yarn melt-spun from the nozzle is introduced into a heating cylinder (for example, heating cylinder temperature 250°C) and instantaneously heat-treated, and can be taken up by a take-up machine installed directly below the nozzle (for example, about 4.5 m away).

[0041] The nozzle for melt extrusion of the artificial hair fiber 10 according to this embodiment can be appropriately selected depending on the shape of the artificial hair fiber 10 to be obtained, the hollow ratio, the number of hollows, the size of the hollows, etc. As an example, when producing an artificial hair fiber 10 having a circular or nearly circular cross section and three hollow portions 20B as shown in Figures 1 and 3, a nozzle with three shallow C-shaped nozzle holes can be used. When producing an artificial hair fiber 10 having a bilobal cross section and two hollow portions 20B as shown in Figure 2A, a nozzle with two deep C-shaped nozzle holes can be used. When producing an artificial hair fiber 10 having a trilobal cross section and three hollow portions 20B as shown in Figure 2B, a nozzle with three deep C-shaped nozzle holes can be used. Furthermore, when producing an artificial hair fiber 10 having a substantially triangular cross section and three hollow portions 20B as shown in Figure 2C, a nozzle having three rod-shaped nozzle holes can be used, and when producing an artificial hair fiber 10 having a substantially square cross section and four hollow portions 20B as shown in Figure 2D, a nozzle having four rod-shaped nozzle holes can be used. In this way, the number of nozzle holes can be set according to the number of hollow portions 20B located in the direction from the hollow portion 20A located approximately in the center toward the outer edge 11 of the artificial hair fiber 10, or the number of hollow portions 20 located near the outer edge 11 of the artificial hair fiber 10 (in other words, the solid portion 30). Furthermore, due to the presence of spaces between the nozzle holes, at least a portion of the resin composition is separated during melt extrusion, but after being discharged from the nozzle holes, the resin compositions come into contact with each other and fuse to form the hollow portions 20. In addition, in one embodiment of the present invention, the resin composition discharged from the nozzle hole swells due to the die swelling effect, and can form the inner protrusions 22 and / or the outer protrusions 24 .

[0042] 1.3.4 Drawing Step and Heat Treatment Step The method for producing artificial hair fiber 10 according to one embodiment of the present invention may also include a drawing step and a heat treatment step. In the drawing step, the undrawn artificial hair fiber 10 obtained in the melt spinning step described above is drawn using a drawing machine to obtain drawn artificial hair fiber 10. As an example, in the drawing step, the undrawn artificial hair fiber 10 can be drawn 2 to 5 times at 90 to 110°C in an air atmosphere. Furthermore, in the heat treatment step, the drawn artificial hair fiber 10 can be heat-treated using a heat treatment machine. As an example, in the heat treatment step, the drawn artificial hair fiber 10 is heat-treated in an air atmosphere at 90 to 110°C to 0.5 to 0.99 times its original size, causing heat shrinkage of the entire fiber length, thereby obtaining heat-treated artificial hair fiber 10 with the desired fineness.

[0043] 1.3.5 Gear Processing Step The manufacturing method for artificial hair fiber 10 according to this embodiment can also include a gear processing step. In this gear processing step, crimping can be achieved by passing the fiber bundle between two meshing high-temperature gears. The material of the gear used in the gear processing step, the shape of the gear waves, and the number of gear fractions are not particularly limited. In the gear processing step, the shape of the resulting artificial hair fiber 10 can be controlled by appropriately adjusting the depth of the gear wave grooves, the gear surface temperature, the processing speed, and the pressure conditions between the gears, taking into consideration the fiber material and fineness. While there are no particular limitations on these processing conditions, as an example, the depth of the gear wave grooves can be 0.2 to 6 mm, preferably 0.5 to 5 mm, the gear surface temperature can be 30 to 100°C, preferably 40 to 80°C, and the processing speed can be 0.5 to 10 m / min, preferably 1.0 to 8.0 m / min.

[0044] The method for manufacturing the artificial hair fiber 10 according to one embodiment of the present invention may include other steps, for example, a surface treatment agent application step.

[0045] In the present invention, the artificial hair fiber 10 includes the artificial hair fiber 10 after spinning, and also encompasses the artificial hair fiber 10 before the drawing process, after the drawing process, before the heat treatment process, after the heat treatment process, before the gear processing process, and after the gear processing process.

[0046] 2. Artificial Hair Fiber Bundle The artificial hair fiber bundle according to this embodiment includes the above-mentioned artificial hair fiber 10. The artificial hair fiber bundle according to this embodiment is preferably made of the above-mentioned artificial hair fiber 10. Note that the above-mentioned "major diameter M in the fiber cross section of the artificial hair fiber" in the artificial hair fiber bundle １ "," "long diameter of hollow portion in fiber cross section," "area ratio of hollow portion in fiber cross section," "length of outer edge of hollow portion in fiber cross section," "number of hollow portions," "S Ｍ / S Ｏ "," "L Ｍ / L Ｏ " indicates the average value of the contained artificial hair fibers 10. These values ​​can be average values ​​based on the observation results of 30 fiber cross sections, for example.

[0047] 2.1 Volume The artificial hair fiber bundle according to this embodiment preferably has a volume (specific volume) of 5 cc / g or more, more preferably 9 cc / g or more. The volume may be, for example, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 cc / g, or may be within a range between any two of the values ​​exemplified here.

[0048] 2.2 Glossiness The artificial hair fiber bundle according to this embodiment preferably has a glossiness of 6.6 or less, more preferably 6.5 or less, and even more preferably 6.2 or less. The lower limit of the artificial hair fiber bundle according to this embodiment is not particularly limited, but is, for example, 4.0. The glossiness may be, for example, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, or 6.6, or may be within a range between any two of the values ​​exemplified here. The glossiness can be measured using a photometer, specifically, by the method described in the examples.

[0049] 2.3 Appearance The artificial hair fiber bundle according to this embodiment preferably has a good appearance. Good appearance means that it has natural variations in color and luster, like human hair. The appearance of the artificial hair fiber bundle can be evaluated visually by an artificial hair fiber processing technician (with at least 5 years of work experience).

[0050] 2.3 Structure Retention In the artificial hair fiber bundle according to this embodiment, the structure retention rate of the fiber cross section of the artificial hair fiber 10 is preferably 90% or more. The structure retention rate may be, for example, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, or 100%, and may be within a range between any two of the values ​​exemplified here. The structure retention rate indicates the percentage of artificial hair fibers 10 in which the hollow portion 20 is entirely covered by the solid portion 30 and the hollow portion 20 has an uncollapsed cross section. Specifically, it can be calculated by the method described in the examples. For example, it can be calculated using the following formula based on the observation results of 300 fiber cross sections: Structure retention rate = (300 - i - j) / 300 i: number of fibers having one or more hollow portions 20 that are not entirely covered by solid portions 30 j: number of fibers whose hollow portions have been crushed and whose inner surfaces have come into contact with each other "Fibers having hollow portions that are not entirely covered by solid portions" refers to a state in which, for example, when the cross section of a fiber has a circular outer edge shape, the cross section is not doughnut-shaped but C-shaped, with some portions separated.

[0051] 3. Hair Accessory Product The hair accessory product according to this embodiment comprises the above-described artificial hair fiber. Also, the hair accessory product according to one embodiment of the present invention comprises the above-described artificial hair fiber bundle.

[0052] The artificial hair fiber bundle according to this embodiment can be used for hair accessory products, such as wigs, hair pieces, braids, hair extensions, doll hair, hair wigs, false hair, and hair bands. Hair accessory products obtained from the artificial hair fiber bundle according to this embodiment have a natural appearance with a color and luster similar to that of human hair.

[0053] Furthermore, the hair accessory product obtained from the artificial hair fiber bundle according to this embodiment maintains the hollow structure of each fiber with high accuracy, and therefore is lightweight, allowing the desired voluminous hairstyle to be achieved with a small amount of attachment, enabling a wide range of hairstyles including heavy long styles to be realized, reducing damage to one's own hair and scalp, and reducing waste and environmental impact. The hair accessory product according to one embodiment of the present invention, which has the above-mentioned characteristics, can be applied to a variety of styles, but is particularly suitable for braids, including braids and twists.

[0054] The present invention will be described in more detail below with reference to examples. Note that the examples described below are representative examples of the present invention and should not be construed as narrowing the scope of the present invention.

[0055] Example 1 Preparation of Resin Composition for Artificial Hair Fibers 70 parts by mass of polyvinyl chloride resin (manufactured by Taiyo Vinyl Corporation, product name: TH1000), 30 parts by mass of vinyl copolymer resin (manufactured by Denka Company, GR-AT-6S) containing 68% by mass of styrene monomer units and 32% by mass of acrylonitrile monomer units, a total of 5 parts by mass of additives such as plasticizers, stabilizers, and lubricants (specifically, 3 parts by mass of stabilizer composition, 1 part by mass of epoxidized soybean oil, 0.4 parts by mass of phosphorus-based chelating agent, and 0.6 parts by mass of polyethylene wax), and 0.5 parts by mass of carbon black were mixed in a blender. The blended materials were kneaded using a φ40 mm single-screw extruder to obtain a resin composition for artificial hair fibers in the form of pellets for spinning. The stabilizer composition used to obtain the resin composition had the following components and composition: Hydrotalcite compound (Mg ４ Al ２ (OH) １２ CO ３ ・3H ２O) 72.6 parts by mass Zinc stearate 13.1 parts by mass Silica ("Carplex (registered trademark) #80" manufactured by DSL Japan Co., Ltd.) 2.2 parts by mass Dibenzoylmethane 2.3 parts by mass Dipentaerythritol 0.9 parts by mass Vinyl chloride resin (product name: TH1000 manufactured by Taiyo PVC Co., Ltd.) 8.9 parts by mass Other additives used to obtain the resin composition are as follows: Epoxidized soybean oil: "ADEKA CIZER (registered trademark) O-130P" manufactured by ADEKA Corporation Phosphorus-based chelating agent: "ADEKA STAB (registered trademark) 1030" manufactured by ADEKA Corporation Polyethylene wax: manufactured by Mitsui Chemicals, Inc.

[0056] <Spinning step> The obtained resin composition for artificial hair fibers in pellet form was spun using a φ40 mm single-screw melt spinning machine. The number of nozzle holes and extrusion speed at this time are shown in Table 1. Undrawn yarn was produced from the molten resin discharged from the nozzle. The cylinder temperature of the spinning machine was set to 180°C, and the nozzle temperature was set to 190°C.

[0057] <Drawing step and heat treatment step> The obtained undrawn yarn was drawn at 100°C and then annealed at 100 to 200°C to obtain a fiber for artificial hair. The draw ratio was 3 times, and the relaxation rate during annealing was 0.5 to 0.99 times. The relaxation rate during annealing is a value calculated by (rotational speed of the take-up roller during annealing) / (rotational speed of the delivery roller during annealing).

[0058] (Examples 2 to 8, Comparative Example 1) By changing the nozzle used in the spinning process, as well as the conditions for the spinning process, drawing process, and heat treatment, artificial hair fibers with different sizes and numbers of hollow portions were obtained. The artificial hair fibers of the Examples and Comparative Examples thus produced were subjected to the tests and evaluations described below, and the results are shown in Table 1.

[0059] <Observation of Fiber Cross Section> First, multiple artificial hair fibers were cut to an appropriate length, and the resulting yarn bundle was wrapped in vinyl tape. The artificial hair fiber bundle was then cut perpendicular to the longitudinal direction with a utility knife to prepare a fiber cross section. A cross-sectional photograph of the fiber was taken at 400x magnification using a laser microscope. Figure 4 shows an enlarged photograph of the cross section of the artificial hair fiber of Example 3. As shown in Figure 4, the outer edge shape of the fiber cross section of all of the artificial hair fibers obtained in each Example and Comparative Example was approximately circular. Furthermore, the largest hollow portion was located approximately in the center of the fiber cross section (i.e., the largest hollow portion was the first hollow portion), and the other hollow portions were located toward the outer edge of the artificial hair fiber from the largest hollow portion (i.e., the other hollow portions were the second hollow portions). Furthermore, the fiber cross section of each Example had inward protrusions that protruded from the other hollow portions (second hollow portions) toward the largest hollow portion (first hollow portion). Based on the photographs of the obtained fiber cross sections, the major diameters of the artificial hair fibers and hollow portions, the number of hollow portions, the shortest distance between the outer edges of adjacent hollow portions, the area ratio of the hollow portions in the fiber cross section, and the length of the outer edges of the hollow portions in the fiber cross section were measured. Each value was calculated as an average using a controller VK-X150 manufactured by Keyence Corporation with an N number of 30. The major diameter M of the fiber cross section of the artificial hair fibers obtained in each Example and Comparative Example was １ The major axis M of the fiber cross section of the largest hollow portion (first hollow portion) was 50 to 150 μm. ２ Furthermore, the major axis M of the fiber cross section of the hollow portion (second hollow portion) other than the largest hollow portion was in the range of 20 to 100 μm. ３ was in the range of 5 to 15 μm.

[0060] <Volume> 120 g of artificial hair fiber bundle was prepared using artificial hair fiber cut to 120 cm, and the artificial hair fiber bundle was placed in a partition with a width of 39.5 mm, folded back at a length of 60 cm. The height of the sample was then measured, and the specific volume was calculated based on the following formula: Partition width × sample length × sample height ÷ fiber mass = specific volume (cc / g)

[0061] <Glossiness> Artificial hair fiber bundles were prepared using artificial hair fibers cut to an appropriate length. The glossiness of each artificial hair fiber bundle was measured using the following device and conditions: Device: Goniophotometer GP-700 manufactured by Murakami Color Research Laboratory Co., Ltd. Incident angle: 45° Sensitivity adjustment dial value (COARSE): 906 Sensitivity adjustment dial value (FINE): 737

[0062] <Appearance> The appearance was evaluated by visually inspecting artificial hair fiber bundles prepared by bundling the artificial hair fibers of Examples and Comparative Examples to a length of 250 mm and a mass of 20 g by 10 artificial hair fiber processing technicians (with at least 5 years of work experience) according to the following criteria. Note that "good appearance" means that the color and luster have natural variations, like human hair. A: 9 or more technicians evaluated the appearance as good B: 6 to 8 technicians evaluated the appearance as good C: 3 to 5 technicians evaluated the appearance as good D: 2 or less technicians evaluated the appearance as good

[0063] <Structure Retention> As in the above <Observation of Fiber Cross Section>, the fiber cross section was photographed at 400x magnification using a laser microscope. Then, the structure retention rate was calculated based on the following formula with an N number of 300. The structure retention rate was calculated using the following formula: Structure retention rate = (300 - i - j) / 300 i: number of fibers having one or more hollow portions 20 that are not entirely covered by solid portions 30 j: number of fibers whose hollow portions have collapsed and whose inner surfaces are in contact with each other "Fibers having hollow portions that are not entirely covered by solid portions" refers to a state in which the cross section is not doughnut-shaped but C-shaped, with some portions separated.

[0064]

[0065] 10: Artificial hair fiber, 11: Outer edge of artificial hair fiber, 20: Hollow portion, 20A: Hollow portion located approximately at the center of the fiber cross section, 20B: Hollow portion located in the direction of the outer edge of the artificial hair fiber from the hollow portion located approximately at the center of the fiber cross section, 21: Outer edge of hollow portion, 22: Inner protrusion, 24: Outer protrusion, 30: Solid portion, M １ : Major axis of artificial hair fiber in fiber cross section, M ２ : major axis of the hollow portion 20A in the fiber cross section, M３ : Major diameter of hollow portion 20B in fiber cross section

Claims

1. An artificial hair fiber, comprising a plurality of hollow portions extending in the longitudinal direction.

2. The artificial hair fiber according to claim 1, wherein a first hollow portion among the plurality of hollow portions is located approximately at the center in a fiber cross section perpendicular to the longitudinal direction of the artificial hair fiber, and one or more second hollow portions among the plurality of hollow portions are each located toward the outer edge of the artificial hair fiber from the first hollow portion in the fiber cross section.

3. The artificial hair fiber according to claim 1, wherein the largest hollow portion among said plurality of hollow portions occupies 5% to 50% of the area of ​​the fiber cross section perpendicular to the longitudinal direction, and the remaining one or more hollow portions occupy, on average, 0.1% to 4% of the area of ​​the fiber cross section.

4. The artificial hair fiber according to claim 3, wherein the largest hollow portion is located approximately at the center of a cross section of the artificial hair fiber perpendicular to the longitudinal direction, and the other one or more hollow portions are each located toward the outer edge of the artificial hair fiber from the largest hollow portion in the cross section of the fiber.

5. The area of ​​the largest hollow portion among the plurality of hollow portions in the fiber cross section perpendicular to the longitudinal direction is S Ｍ The total area of ​​one or more other hollow portions in the fiber cross section is S Ｏ Then, S Ｍ / S Ｏ 2. The fiber for artificial hair according to claim 1, wherein the molecular weight is 5 to 40.

6. The length of the outer edge of the largest hollow portion among the plurality of hollow portions in the fiber cross section perpendicular to the longitudinal direction is L. Ｍ The total length of the outer edge of one or more other hollow portions in the fiber cross section is L Ｏ When this is done, L Ｍ / L Ｏ The fiber for artificial hair according to claim 1, wherein the fiber length is 1.3 to 3.

8.

7. The artificial hair fiber according to any one of claims 1 to 6, wherein the shortest distance between the outer edges of adjacent hollow portions among the plurality of hollow portions is 3 μm to 30 μm.

8. An artificial hair fiber according to any one of claims 2 to 6, comprising, in the fiber cross section, at least one of an inner protrusion protruding from one or more of the remaining hollow portions toward one of the plurality of hollow portions, and an outer protrusion protruding from one or more of the plurality of hollow portions toward the outer edge of the artificial hair fiber.

9. The artificial hair fiber according to any one of claims 1 to 6, wherein the number of the plurality of hollow portions is three or more.

10. The fiber for artificial hair according to any one of claims 1 to 6, which contains a vinyl chloride resin.

11. A hair accessory product comprising the artificial hair fiber according to any one of claims 1 to 6.

12. A hair accessory product according to claim 11, comprising a braid.

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