Fiber bundles and hair ornament products

Abstract

The object of this invention is to provide a fiber bundle having a soft texture. [Solution] One aspect of the present invention is a fiber bundle containing a plurality of artificial hair fibers, wherein the fiber density of the artificial hair fibers is 0.5 to 1.2 g / cm³. 3 This is a fiber bundle. Furthermore, for the above fiber bundle, 2.0 cm 2 When a compression test was performed using a circular planar terminal at a speed of 1 mm / second from 0 kPa to 49 kPa, the compressive stiffness LC was 0.12 or less.

Description

[Technical Field]

[0001] In hair accessories such as wigs, hairpieces, hair extensions, headbands, and doll hair, artificial hair is used in addition to human hair, or as a substitute for human hair. Materials that make up artificial hair fibers include acrylic resins, polyvinyl chloride resins, and polyester resins, and artificial hair fibers made from these resins are commercially available.

[0002] Patent Document 1 discloses artificial hair characterized by containing hollow fibers having a hollow portion with a hollow ratio of 10 to 50%. Patent Document 2 discloses a fiber for artificial hair characterized by 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% or more and 50% or less, the cross-sectional shape of the fiber cross-section being a flat multi-lobed shape, and the void having a first side and a second side that are inclined at an angle of 70 degrees or more and 110 degrees or less with respect to the long axis of the fiber cross-section. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2008-285772 [Patent Document 2] WO2014 / 196642 [Overview of the project] [Problems that the invention aims to solve]

[0004] When conventional artificial hair fibers were bundled together to form fiber bundles, they did not have the soft texture of human hair, which sometimes caused discomfort for the user.

[0005] This invention has been made in view of these circumstances, and aims to provide a fiber bundle having a soft texture. [Means for solving the problem]

[0006] Through diligent research, the inventors discovered that the above problems could be solved by adjusting the shape of the artificial hair fibers and fiber bundles, thereby setting the specific gravity of the artificial hair fibers and the compressive stiffness of the fiber bundles within a specific range, and thus completed the present invention.

[0007] According to the present invention, the following is provided: [1] A fiber bundle containing multiple artificial hair fibers, The fiber density of the above-mentioned artificial hair fibers is 0.5~1.2 g / cm³ 3 And, Regarding the above fiber bundle, 2.0 cm 2 A fiber bundle in which the compressive stiffness LC is 0.12 or less when a compression test is performed using a circular planar terminal at a speed of 1 mm / second from 0 kPa to 49 kPa. [2] The fiber bundle according to [1], wherein the major axis of the fiber cross-section perpendicular to the longitudinal direction of the artificial hair fiber is 50 to 100 μm. [3] The compression power WC obtained when the above compression test was performed on the above fiber bundle was 0.20 N·cm / cm 2 The fiber bundle described above, as in [1] or [2]. [4] The artificial hair fiber comprises a hollow portion extending in the longitudinal direction of the artificial hair fiber, The fiber bundle according to any one of [1] to [3], wherein the area occupied by the hollow portion in the fiber cross-section perpendicular to the longitudinal direction of the artificial hair fiber is defined as the hollow ratio, and the hollow ratio is 20% or more. [5] The fiber bundle according to any one of [1] to [4], wherein the fiber bundle has a helical shape. [6] The fiber bundle according to [5], wherein the pitch of the spiral shape of the fiber bundle is 2.0 to 12.0 mm. [7] The fiber bundle according to [5] or [6], wherein the spiral diameter of the spiral shape of the fiber bundle is 2.0 to 15.0 mm. [8] A fiber bundle according to any one of [5] to [7], wherein the length of the fiber bundle after forming the helical shape is 10 to 85% of the length of the fiber bundle before forming the helical shape, which is taken as the standard (100%). [9] A fiber bundle according to any one of [1] to [8], wherein each fiber bundle contains 300 to 2500 of the artificial hair fibers. A hair ornament product containing multiple fiber bundles as described in any of

[10] [1] to [9]. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a fiber bundle having a soft texture. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic cross-sectional view of an artificial hair fiber according to one embodiment of the present invention. Figure 1A shows a circular cross-section, Figure 1B shows a circular cross-section having an inner protrusion and an outer protrusion, Figure 1C shows a two-lobed cross-section formed by joining two C-shapes, Figure 1D shows a three-lobed cross-section formed by joining three C-shapes, Figure 1E shows a roughly triangular cross-section, and Figure 1F shows a roughly square cross-section. [Figure 2] Figure 2 is a schematic diagram of a fiber bundle having a helical shape according to one embodiment of the present invention, illustrating the helical pitch, helical diameter, and perimeter of the fiber bundle. [Figure 3] Figure 3 is a schematic diagram illustrating the spiral shape formation process in a method for manufacturing fiber bundles according to one embodiment of the present invention. [Figure 4] Figure 4 is a schematic diagram of the fiber cross-section of the artificial hair fiber in the embodiment. [Modes for carrying out the invention]

[0010] The present invention will now be described in detail. The present invention is not limited to these descriptions. The features of the embodiments shown below can be combined with each other. Furthermore, each feature constitutes an invention independently. In addition, any element of the embodiments below that is not defined in the claims is optional and can be omitted. In this specification, any number of zeros may be added to the end of numerical values. For example, one zero may be added after "1.4" to make it "1.40".

[0011] <Explanation of Terms> In this specification, for example, the description "X to Y" means X or more and Y or less.

[0012] 1 Fiber for artificial hair 1.1 Fiber density of fiber for artificial hair The fiber for artificial hair according to this embodiment has a fiber density of 0.5 to 1.2 g / cm 3 and preferably 0.6 to 1.1 g / cm 3 and more preferably 0.7 to 1.0 g / cm 3 Here, the "fiber density" in this specification means the mass per volume based on the outer edge of the fiber. Here, the "volume based on the outer edge of the fiber" means, for example, when the fiber for artificial hair has the hollow and / or voids described later, the volume including the hollow part and the voids. That is, the fiber density may not coincide with the density of the resin itself constituting the fiber for artificial hair. The volume based on the outer edge of the fiber can be estimated from the area based on the outer edge of the fiber (the outer surface 11 in FIG. 1) obtained by cutting the fiber for artificial hair perpendicular to the longitudinal direction, observing the cut surface with a laser microscope or a scanning electron microscope, and performing image analysis, and specifically, it can be obtained by the method described in the examples. The volume based on the outer edge of the fiber can be the average value when a plurality of fibers are observed, and for example, it can be the average value of n number (fiber number) 50. The fiber density of the fiber for artificial hair is, for example, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1 or 1.2 g / cm 3It may be any value exemplified herein, or may be within the range between any two of the exemplified numerical values. When the fiber density of the fiber for artificial hair is at least the lower limit value, the stiffness of the fiber bundle becomes sufficient, and thus the user is less likely to feel discomfort. Also, the strength of the fiber for artificial hair becomes sufficient and the shape of the fiber cross-section is easily maintained. When the fiber density of the fiber for artificial hair is at most the upper limit value, the fiber bundle has a soft touch, and thus the user is less likely to feel discomfort. The fiber density of the fiber for artificial hair can be adjusted, for example, by the composition of the resin composition constituting the fiber and the shape of the fiber for artificial hair (specifically, providing a hollow portion or voids described later and their sizes).

[0013] 1.2 Shape of the Fiber for Artificial Hair The shape of the fiber cross-section perpendicular to the longitudinal direction of the artificial hair fiber according to this embodiment (hereinafter simply referred to as "fiber cross-section") is not particularly limited as long as the fiber density is within the range described above. The artificial hair fiber according to this embodiment typically has a hollow portion extending in the longitudinal direction. In this specification, a "hollow portion" is defined as a portion that exists continuously for 3 cm or more in the longitudinal direction of the artificial hair fiber and has a major axis of 1 μm or more in the fiber cross-section. In some cases, a hollow portion of 3 cm (preferably 4 cm, 5 cm, or 10 cm) or more is continuously provided in the longitudinal direction of the artificial hair fiber via a solid portion of 1 cm (preferably 0.5 cm) or less. In this case, there is a partially discontinuous portion in the hollow portion in the longitudinal direction of the artificial hair fiber, but it is preferable that 80% (preferably 90%) or more of the total length in the longitudinal direction of the artificial hair fiber is a hollow portion. It is particularly preferable that the hollow portion is continuous in the longitudinal direction of the artificial hair fiber (i.e., 100% of the total length is a hollow portion). Although the fiber cross-sections shown in Figure 1 all have one hollow section, artificial hair fibers having fiber cross-sections with multiple hollow sections (for example, 2 to 10) are also one embodiment of the present invention. Furthermore, artificial hair fibers having one or more voids (voids that exist in the artificial hair fiber but are not hollow sections (i.e., those that do not exist continuously for 3 cm or more in the longitudinal direction of the artificial hair fiber, or whose major axis in the fiber cross-section is less than 1 μm)) are also one embodiment of the present invention. By having hollow sections and / or voids in artificial hair fibers, the compression power WC of the fiber bundle can be increased. In addition, by having hollow sections and / or voids in artificial hair fibers, the fiber density of the artificial hair fibers decreases, resulting in a softer feel for the fiber bundle.

[0014] Figure 1 shows an example of a fiber cross-section of an artificial hair fiber having a hollow portion according to one embodiment of the present invention. The outer edge shape of the cross-section perpendicular to the longitudinal direction of the artificial hair fiber according to this embodiment can be selected from a circular shape (Figures 1A and 1B), an elliptical shape, a two-lobed shape formed by joining two C-shapes (Figure 1C), a three-lobed shape formed by joining three C-shapes (Figure 1D), a four-lobed shape formed by joining four or more C-shapes, and a substantially triangular shape (Figure 1E), a substantially quadrilateral shape (Figure 1F), and a substantially polygonal shape.

[0015] The method for manufacturing the artificial hair fibers according to this embodiment is not particularly limited, but artificial hair fibers are generally obtained by melt spinning a resin composition. Artificial hair fibers having a hollow portion are formed, for example, by melt extrusion from a nozzle having one C-shaped nozzle hole or a nozzle having multiple holes. Here, at least a portion of the resin composition is divided while passing through the nozzle, but after being discharged from the nozzle hole, the resin composition pieces come into contact with each other and fuse together, forming a hollow portion. The artificial hair fibers according to this embodiment may have a joint surface 14 (shown by a dashed line in Figure 1) where the resin composition pieces are fused together during the melt extrusion process. Furthermore, the joint portion 13, which is the region including the joint surface 14, may have at least one of an inner projection 16 that protrudes toward the hollow portion and an outer projection 17 that protrudes toward the outside of the artificial hair fiber (Figure 1B). Figure 1B shows the case where the fiber cross-section is circular, but even if the fiber cross-section has other shapes, at least one of the following can be provided in the joint 13: an inner projection 16 that protrudes toward the hollow portion and an outer projection 17 that protrudes toward the outside of the artificial hair fiber. In this way, by providing projections and making the joint 13 thicker, the joint strength can be improved by increasing the area of ​​the joint surface 14 where the resin compositions are fused together. The manufacturing method will be described later.

[0016] When the artificial hair fiber according to this embodiment has a hollow portion, the hollow ratio is defined as the area occupied by the hollow portion in the fiber cross-section. The hollow ratio can be, for example, 10% or more, preferably 20% or more, and more preferably 25% or more. The upper limit of the hollow ratio can be, for example, 50%. The hollow ratio of the artificial hair fiber may be, for example, 10, 15, 20, 25, 30, 35, 40, 45, or 50%, and may be within the range of any two of the values ​​exemplified here. The hollow ratio can be calculated using the following formula. (Hollow ratio) = {(Area enclosed by inner surface 12) / (Area enclosed by outer surface 11)} × 100 The area enclosed by the outer surface 11 represents the cross-sectional area assuming that the artificial hair fiber has no hollow parts. Furthermore, if multiple hollow parts exist in a cross-section perpendicular to the longitudinal direction of the artificial hair fiber, the area enclosed by the inner surface 12 can be the sum of the areas enclosed by the inner surfaces of each hollow part. The hollow ratio can be determined by cutting the artificial hair fiber 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. The hollow ratio can be the average value when observing multiple fibers; for example, it can be the average value of n (number of fibers) 50. If the hollow ratio is above the lower limit, the fiber density of the artificial hair fiber decreases, resulting in a softer feel for the fiber bundle. If the hollow ratio is below the upper limit, structural defects (such as separation of joints or collapse of hollow parts) are suppressed. Furthermore, when the fineness is constant, the major diameter of the artificial hair fibers becomes smaller, which prevents an increase in compressive stiffness LC, and consequently results in a softer feel for the fiber bundle.

[0017] The major axis of the fiber cross-section perpendicular to the longitudinal direction of the artificial hair fiber according to this embodiment can be, for example, 30 to 300 μm, preferably 50 to 100 μm, more preferably 75 to 90 μm, and even more preferably 80 to 85 μm. In this specification, "major axis" refers to the largest distance when the fiber cross-section is sandwiched between two parallel lines. The major axis of the fiber cross-section of the artificial hair fiber may be 30, 50, 70, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 100, 150, 200, 250, or 300 μm, and may be within the range of any two of the values ​​exemplified here. The major axis of the fiber cross-section of artificial hair fibers can be determined by cutting the artificial hair fiber perpendicular to its 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. The major axis of the fiber cross-section of artificial hair fibers can be the average value obtained when observing multiple fibers, for example, the average value of n (number of fibers) 50. If the major axis of the fiber cross-section of artificial hair fibers is above the lower limit, the strength will be sufficient. If the major axis of the fiber cross-section of artificial hair fibers is below the upper limit, an increase in compressive stiffness LC can be prevented, and consequently, the fiber bundle will have a softer feel.

[0018] The fineness of the artificial hair fibers according to this embodiment can be, for example, 35 to 55 d (denier), preferably 40 to 50 d, and more preferably 42 to 48 d. The fineness of the artificial hair fibers may be, for example, 35, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, or 55 d, and may be within the range of any two of the values ​​exemplified here. If the fineness of the artificial hair fibers is above the lower limit, the strength will be sufficient. If the fineness of the artificial hair fibers is below the upper limit, the fiber bundle will have a softer feel.

[0019] The fiber thickness in the fiber cross-section of the artificial hair fiber according to this embodiment can be, for example, 2 to 50 μm, preferably 5 to 40 μm, and more preferably 10 to 30 μm. In this specification, "fiber thickness" is synonymous with the major axis described above if there is no hollow portion, and means the shortest distance from the outer surface 11 to the inner surface 12 if there is a hollow portion. The fiber thickness in the fiber cross-section of an artificial hair fiber with a hollow portion can be determined by cutting the artificial hair fiber perpendicular to the longitudinal direction, observing the cut surface with a laser microscope or scanning electron microscope, and performing image analysis. Specifically, the fiber thickness in the fiber cross-section of a single fiber can be the average value of the shortest distance from the outer surface 11 to the inner surface 12 measured at any five locations on the outer surface 11 of the fiber cross-section of a single fiber. The fiber thickness in the fiber cross-section of an artificial hair fiber can be the average value when observing multiple fibers, for example, the average value of n (number of fibers) 50. The fiber thickness in the cross-section of the artificial hair fiber may be 2, 5, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 35, 40, 45, or 50 μm, and may be within the range of any two of the values ​​exemplified here. Since the artificial hair fiber according to this embodiment is preferably a hollow fiber, even with such a fiber thickness, sufficient strength is obtained, and the fiber bundle has a softer feel. If the fiber thickness is above the lower limit, the strength is sufficient. If the fiber thickness is below the upper limit, the fiber bundle has a softer feel.

[0020] 1.3 Composition of fibers for artificial hair 1.3.1 Resin composition The resin composition constituting the artificial hair fibers according to this embodiment is not particularly limited and may include at least one of the following: vinyl chloride resin, vinyl chloride-acrylonitrile copolymer, polyester resin such as polyethylene terephthalate, polyamide resin, polypropylene resin (PP resin), polyethylene resin (PE resin), polyacrylonitrile resin (PAN resin), polylactic acid resin (PLA resin), and acrylonitrile-styrene copolymer. The artificial hair fibers according to this embodiment preferably contain vinyl chloride resin from the viewpoint of making it easier for the fiber bundle to maintain a helical shape, making it easier to obtain a die swell effect, and making it easier to obtain a hollow fiber with a structure having a protruding portion that increases the area of ​​the joint surface where the resin compositions are fused together, thereby improving the bonding strength. Furthermore, the resin composition according to the embodiment preferably contains vinyl chloride resin and AS resin (acrylonitrile styrene resin).

[0021] The vinyl chloride resin according to this embodiment may include a vinyl chloride polymer containing monomer units derived from vinyl chloride monomer (vinyl chloride monomer units). The content of vinyl chloride monomer units per 100% by mass of the vinyl chloride resin may be, for example, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100% by mass, and may be within the range of any two of the values ​​exemplified herein. The vinyl chloride resin according to this embodiment may include a homopolymer obtained by homopolymerizing vinyl chloride monomer, and / or a copolymer containing a vinyl chloride monomer and monomer units derived from other monomers 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 vinyl chloride resin according to this embodiment may consist of one type of vinyl chloride polymer, or it may contain two or more types of vinyl chloride polymers.

[0022] The resin composition according to this embodiment preferably contains 50% by mass or more of vinyl chloride resin, and more preferably 65% ​​by mass or more, of the resin contained in 100% by mass of the resin in the resin composition. The content of vinyl chloride resin relative to 100% by mass of the resin contained in the resin composition may be, for example, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100% by mass, and may be within a range between any two of the values ​​exemplified herein.

[0023] The resin composition according to this embodiment preferably contains 50% by mass or more of vinyl chloride monomer units per 100% by mass of resin contained in the resin composition, and more preferably 65% ​​by mass or more. The content of vinyl chloride monomer units per 100% by mass of resin contained in the resin composition may be, for example, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100% by mass, and may be within a range between any two of the values ​​exemplified herein.

[0024] The resin composition according to this embodiment may also contain resins other than vinyl chloride resins, and may contain both vinyl chloride resins and resins other than vinyl chloride resins. When the resin composition according to this embodiment contains both a vinyl chloride resin and a resin other than a vinyl chloride resin, the resin other than the vinyl chloride resin preferably has excellent compatibility with the vinyl chloride resin, and compatibility can be adjusted by adjusting the type and amount of monomer units contained in the other resin and the molecular weight. An example of a resin other than a vinyl chloride resin used in combination with a vinyl chloride resin is an AS resin (acrylonitrile styrene resin). The AS resin is a copolymer having styrene monomer units and acrylonitrile monomer units, and may contain other monomer units copolymerizable with these as needed. The AS resin contains, for example, 60, 65, 70, 75, 80, 85, or 90% by mass of styrene monomer units per 100% by mass of the AS resin, and may be within a range between any two of the values ​​exemplified here. The AS resin contains, for example, 10, 15, 20, 25, 30, 35, or 40% by mass of acrylonitrile monomer units per 100% by mass of the AS resin, and may be within a range between any two of the values ​​exemplified herein.

[0025] The resin composition according to this embodiment may also contain other components as needed. Other components include stabilizers, antistatic agents, heat stabilizers, lubricants, colorants, processing aids, plasticizers, reinforcing agents, UV absorbers, antioxidants, fillers, flame retardants, pigments, initial color improvers, conductivity imparters, and fragrances. Examples of other components according to this embodiment include hydrotalcite compounds, zinc organic acid salts (e.g., zinc stearate), silica, β-diketone compounds (e.g., dibenzoylmethane), polyols (e.g., dipentaerythritol), epoxy compounds (e.g., epoxidized soybean oil), organic phosphite compounds (e.g., phosphorus-based chelating agents), polyethylene wax, and the like. The resin composition according to this embodiment may contain, for example, 10 parts by mass or less, and more preferably 5.5 parts by mass or less, of other components per 100 parts by mass of resin.

[0026] 1.3.2 Surface treatment agents The artificial hair fibers according to this embodiment may have a surface treatment agent attached to their surface. The surface treatment agent can be one or more selected from the group consisting of oils, nonionic surfactants, and cationic surfactants. The amount of surface treatment agent attached is preferably 0.05 to 1.0% by mass, and more preferably 0.1 to 0.5% by mass, based on 100% by mass of the artificial hair fibers. The amount of surface treatment agent attached may be, for example, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1.0% by mass, based on 100% by mass of the artificial hair fibers, and may be within the range of any two of the values ​​exemplified here.

[0027] 1.3.2.1 Oil content The surface treatment agent according to this embodiment preferably contains oil. Examples of oils according to this embodiment include fatty acid skeleton-containing compounds (fatty acids, glycerides, and organic acid glycerides), polyalkylene glycols, alkyl alkylates, and mineral oils.

[0028] 1.3.2.2 Nonionic surfactants Examples of nonionic surfactants according to this embodiment include polyoxyethylene fatty acid esters, polyoxyalkylene alkyl ethers, polyoxyethylene alkyl ethers, polyoxyethylene hydrogenated castor oil ethers, polyoxyethylene alkylphenyl ethers, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, sucrose fatty acid esters, glycerin fatty acid esters, polyoxyethylene polyoxypropylene block polymers, polyoxyethylene alkylamine ethers, and fatty acid alkanolamides.

[0029] 1.3.2.3 Cationic surfactants Examples of cationic surfactants according to this embodiment include quaternary ammonium salts having alkyl groups such as oxyalkylene groups, alkyltrimethylammonium salts, dialkyldimethylammonium salts and alkyldimethylethylammonium salts, ammonium salts having ester bonds such as stearooxymethylpyridinium salts, fatty acid triethanolamine and fatty acid triethanolamine formate, and amine derivatives having alkyl chains such as polyoxyethylene alkylamine, N-alkylpropyleneamine and N-alkyl polyethylene polyamine.

[0030] 1.4 Method for manufacturing fibers for artificial hair The method for producing artificial hair fibers according to this embodiment includes a resin composition preparation step and a spinning step, and may further include a stretching step, a heat treatment step and a gear processing step. Furthermore, the method for producing artificial hair fibers according to this embodiment may include a surface treatment agent application step.

[0031] 1.4.1 Resin composition preparation process In the resin composition preparation process, a resin composition can be obtained by mixing raw materials containing a resin. Here, the raw materials include a base resin and may contain other components as needed.

[0032] The mixing method is not particularly limited, and conventionally known methods can be used. For example, a powdered resin composition (powder compound) can be obtained using known mixing equipment such as a Henschel mixer, a super mixer, and a ribbon blender, and then the powder compound can be melt-mixed to obtain a pelletized resin composition (pellet compound). The method for producing the powder compound can be either hot blending or cold blending. For example, in order to reduce volatile matter from the resin composition, hot blending can be performed with a cut-off temperature of 105 to 155°C during mixing. The method for producing the pellet compound can be the same as the method for producing a general vinyl chloride resin pellet compound. For example, a pellet compound can be produced using a kneader such as a single-screw extruder, an asymmetric twin-screw extruder, a conical twin-screw extruder, a co-screw extruder, a cone 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 lower in order to prevent thermal degradation of the resin composition. Furthermore, a mesh can be installed near the tip of the screw to remove small amounts of metal fragments from the screw or fibers from protective gloves that may be mixed into the pellet compound. The cold-cut method can be used for pellet production. Measures may be taken to remove metal shavings (fine powder generated during pellet production) that may be mixed in during the cold-cut process. Also, since the cutter blades may become dull and more prone to generating metal shavings after prolonged use, it is preferable to replace them as needed.

[0033] 1.4.2 Spinning Process In the spinning process, the resin composition is melt-spun to obtain fibers for artificial hair. As an example, the resin composition (e.g., pellet compound) can be extruded from a heated cylinder through a nozzle and melt-spun. Conventional extruders can be used as the extruder, such as single-screw extruders, opposite-direction twin-screw extruders, and conical twin-screw extruders.

[0034] The melt spinning conditions can be appropriately set according to the composition of the resin composition so that the resin melts. In one embodiment of the present invention, the melt spinning conditions can be appropriately set so that the joints are joined and a hollow portion is formed. For example, the cylinder temperature can be 150 to 190°C, and the nozzle temperature can be 155 to 195°C. The extrusion speed is preferably 5 to 20 kg / h, and more preferably 8 to 18 kg / h. When the temperature and extrusion speed are within this range, a hollow portion is easily formed, resulting in a suitable size.

[0035] The undrawn yarn, melt-spun from the nozzle, is introduced into a heating cylinder (e.g., heating cylinder temperature 250°C) for instantaneous heat treatment and can be wound up by a take-up machine installed directly below the nozzle (e.g., approximately 4.5 m).

[0036] The shape of the nozzle for melt extrusion of the artificial hair fibers according to this embodiment can be appropriately selected according to the shape and hollowness of the artificial hair fibers to be obtained. For example, when manufacturing artificial hair fibers having a circular cross-section and a hollow portion as shown in Figure 1A, a nozzle with a C-shaped nozzle hole can be used. When manufacturing artificial hair fibers having a two-lobed cross-section formed by joining two C-shapes and a hollow portion as shown in Figure 1C, a nozzle with two C-shaped nozzle holes can be used. When manufacturing artificial hair fibers having a three-lobed cross-section formed by joining three C-shapes and a hollow portion as shown in Figure 1D, a nozzle with three C-shaped nozzle holes can be used. Furthermore, when manufacturing artificial hair fibers having a roughly triangular cross-section and a hollow portion as shown in Figure 1E, a nozzle with three rod-shaped nozzle holes can be used. When manufacturing artificial hair fibers having a roughly square cross-section and a hollow portion as shown in Figure 1F, a nozzle with four rod-shaped nozzle holes can be used. Although at least a portion of the resin composition is separated during melt extrusion due to the spacing between the nozzle holes, after being discharged from the nozzle holes, the resin composition pieces come into contact and fuse together, forming a hollow space. In addition, in this embodiment, the resin composition discharged from the nozzle holes expands due to the die swell effect, causing the formation of inner and / or outer protrusions.

[0037] 1.4.3 Stretching process The method for producing artificial hair fibers according to this embodiment may also include a stretching step. In the stretching step according to this embodiment, the unstretched artificial hair fibers obtained in the melt spinning step described above are stretched in a stretching machine to obtain post-stretching artificial hair fibers. For example, in the stretching step, the unstretched artificial hair fibers can be stretched to 2 to 5 times their original length at 90 to 110°C in an air atmosphere, for example.

[0038] 1.4.4 Heat treatment process The method for manufacturing artificial hair fibers according to this embodiment may also include a heat treatment step. In the heat treatment step according to this embodiment, the artificial hair fibers after the stretching step can be heat-treated using a heat treatment machine. For example, in the heat treatment step, the artificial hair fibers after the stretching step can be heat-treated at 90 to 120°C in an air atmosphere to reduce their size to 0.5 to 0.99 times, thereby thermally shrinking the entire length of the fibers and obtaining artificial hair fibers after the heat treatment step with a desired fineness. The "relaxation rate during heat treatment" is a value calculated as (rotation speed of the winding roller during annealing) / (rotation speed of the feed roller during annealing).

[0039] 1.4.5 Surface treatment agent application process The method for manufacturing artificial hair fibers according to this embodiment may also include a surface treatment agent application step. The surface treatment agent application step is not particularly limited as long as the surface treatment agent can be applied to the fibers, and any application method can be used. For example, the surface treatment agent may be applied to the fibers by a roll transfer method, or the fibers may be immersed in a solution containing the surface treatment agent to apply it. The amount of surface treatment agent applied can be adjusted by adjusting the amount of preparation or by adjusting the concentration of each component other than the solvent in the solution containing the surface treatment agent.

[0040] 1.4.6 Gear Machining Process The method for manufacturing artificial hair fibers according to this embodiment may also include a gear processing step. In the gear processing step, crimping can be applied by passing a fiber bundle between two meshing, high-temperature gears. The material of the gears used in the gear processing step, the shape of the gear's wave, the number of teeth on the gear, etc., are not particularly limited. In the gear processing step, the shape of the resulting artificial hair fibers can be controlled by appropriately adjusting the depth of the gear's wave groove, the gear's surface temperature, the processing speed, the pressure conditions between the gears, etc., taking into consideration the fiber material and fineness. There are no particular limitations on these processing conditions, but as an example, the depth of the gear's wave groove can be 0.2 to 6 mm, preferably 0.5 to 5 mm, the gear's 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.

[0041] In this invention, the term "artificial hair fibers" includes artificial hair fibers after spinning, and encompasses artificial hair fibers before the stretching process, after the stretching process, before the heat treatment process, after the heat treatment process, before the surface treatment agent application process, after the surface treatment agent application process, before the gear processing process, and after the gear processing process.

[0042] 2 Fiber bundles The fiber bundle according to this embodiment includes a plurality of artificial hair fibers, including the artificial hair fibers described above. In addition, in one embodiment of the present invention, the fiber bundle may include artificial hair fibers other than those described above (for example, solid artificial hair fibers) and / or human hair. The composition of the solid artificial hair fibers can be the same as that of the artificial hair fibers described above, and the solid artificial hair fibers can be obtained by changing the shape of the nozzle in the spinning process in the manufacturing method described above for dispensing solid fibers. In the fiber bundle according to this embodiment, when the total amount of fibers in the fiber bundle is taken as 100% by mass, the content of the artificial hair fibers described above can be 50% by mass or more, for example, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 or 100% by mass, and may be within the range of any two of the values ​​exemplified here. The fiber bundle according to this embodiment preferably consists only of the artificial hair fibers described above.

[0043] 2.1 Fiber bundle structure The number of artificial hair fibers contained in one fiber bundle according to this embodiment is, for example, 100 to 3000, preferably 300 to 2500, more preferably 400 to 2200, and even more preferably 500 to 2000. The number of artificial hair fibers contained in one fiber bundle may be, for example, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 2000, 2200, 2500, or 3000, and may be within the range of any two of the values ​​exemplified here. If the number of artificial hair fibers contained in one fiber bundle is greater than or equal to the lower limit, the pitch of the spiral shape tends to become larger when the spiral shape described later is formed, and consequently the value of the compressive stiffness LC is reduced. If the number of artificial hair fibers contained in one fiber bundle is below the upper limit, the pitch of the spiral shape tends to become smaller when the spiral shape described later is formed, and consequently the value of the compression power WC increases.

[0044] The mass of one fiber bundle according to this embodiment is, for example, 3.0 to 14.0 g. The mass of one fiber bundle may also be, for example, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, 10.5, 11.0, 11.5, 12.0, 12.5, 13.0, 13.5, or 14.0 g, and may be within the range of any two of the values ​​exemplified here.

[0045] The total length of the fiber bundle according to this embodiment (i.e., the total length of each fiber before forming the helical shape described later) is, for example, 500 to 3000 mm, preferably 700 to 2000 mm, and more preferably 1000 to 1500 mm. The total length of the fiber bundle may also be, for example, 500, 600, 700, 800, 900, 1000, 1200, 1300, 1400, 1500, 2000, 2500, or 3000 mm, and may be within the range of any two of the values ​​exemplified herein.

[0046] 2.2 Spiral shape of fiber bundles The fiber bundle according to this embodiment typically has a helical shape. The helical shape of the fiber bundle reduces the compressive stiffness LC of the fiber bundle, resulting in a softer feel.

[0047] The spiral shape according to this embodiment will be explained with reference to Figure 2. Figure 2 is a schematic diagram of a fiber bundle, showing a state in which one end of the fiber bundle 200 is fixed to a support 21 and the fiber bundle 200 is suspended in the vertical direction. The fiber bundle according to this embodiment has a spiral shape (approximately spiral shape), and can be a helical spiral shape in which the fiber bundle is wound around a virtual cylinder. In this specification, "pitch" means the distance in the direction of the central axis of the spiral when the spiral completes one rotation around the virtual cylinder, and can also be the distance (wavelength) between the peaks of a wave shape obtained by projecting the spiral shape onto a plane parallel to the central axis of the spiral shape. In this specification, "spiral diameter" means the diameter of the spiral, and can also be the amplitude of the wave shape obtained by projecting the spiral shape onto a plane parallel to the central axis of the spiral shape. In this specification, "perimeter" means the circumference of the spiral when the fiber bundle has a spiral shape, and can also be the circular circumference obtained by projecting the spiral shape onto a plane perpendicular to the central axis of the spiral shape. On the other hand, "perimeter" refers to the minimum perimeter when the fiber bundles are bundled so that their cross-section is approximately circular, assuming the fiber bundles do not have a spiral shape.

[0048] In this embodiment, the spiral pitch of the fiber bundle is preferably 2.0 to 12.0 mm, and more preferably 3.0 to 9.0 mm. The spiral pitch of the fiber bundle may be, for example, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, or 12.0 mm, and may be within the range of any two of the values ​​exemplified here. The spiral pitch of the fiber bundle can be, for example, the average value of the 2nd to 11th spirals (n=10) from the top immediately after fixing one end of the fiber bundle to a support and suspending the fiber bundle vertically. If the spiral pitch of the fiber bundle is above the lower limit, the value of the compressive stiffness LC is reduced. If the spiral pitch of the fiber bundle is below the upper limit, the value of the compressive power WC is increased. The pitch of the spiral shape of the fiber bundle can be controlled by adjusting the type and amount of fibers contained in the fiber bundle, as well as the method of winding the fiber bundle during the spiral shape formation process.

[0049] In this embodiment, the spiral diameter of the helical shape of the fiber bundle is preferably 2.0 to 15.0 mm, more preferably 3.0 to 13.0 mm, and even more preferably 5.0 to 10.0 mm. The spiral diameter of the helical shape of the fiber bundle may be, for example, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, 12.0, 13.0, 14.0, or 15.0 mm, and may be within the range of any two of the values ​​exemplified here. The spiral diameter of the helical shape of the fiber bundle can be, for example, the average value of the 2nd to 11th helix (n=10) from the top immediately after fixing one end of the fiber bundle to a support and suspending the fiber bundle vertically. If the spiral diameter of the helical shape of the fiber bundle is greater than or equal to the lower limit, the value of the compressive stiffness LC is reduced, and the value of the compressive power WC is increased, making the fiber bundle softer. The spiral diameter of the fiber bundle can be controlled by adjusting the type and amount of fibers contained in the bundle, as well as the diameter of the jig used to wind the fiber bundle during the spiral formation process.

[0050] The circumference of the spiral shape of the fiber bundle according to this embodiment is preferably 5 to 50 mm, preferably 8 to 45 mm, and more preferably 10 to 40 mm. The circumference of the fiber bundle may be, for example, 5, 8, 10, 15, 20, 25, 30, 35, 40, 45, or 50 mm, and may be within the range of any two of the values ​​exemplified herein.

[0051] In this embodiment, the length of the fiber bundle after forming the spiral shape is preferably 100 to 1100 mm, more preferably 150 to 800 mm, and even more preferably 200 to 700 mm. The length of the fiber bundle after forming the spiral shape is, for example, 100, 150, 200, 250, 300, 350, 400, 450, 500, 600, 700, 800, 900, 1000, or 1100 mm, and may be within the range of any two of the values ​​exemplified here. The length of the fiber bundle after forming the spiral shape can be the length when the fiber bundle is laid flat. The length of the fiber bundle after forming the spiral shape can be controlled by adjusting the pitch and diameter of the spiral shape, the type and amount of fibers included in the fiber bundle, and the method of winding the fiber bundle in the spiral shape formation process.

[0052] Furthermore, regarding the length of the fiber bundle before and after the formation of the spiral shape according to this embodiment, when the length of the fiber bundle before the formation of the spiral shape is taken as the base (100%), the length of the fiber bundle after the formation of the spiral shape is preferably 10-85%, more preferably 15-60%, and even more preferably 25-35%. When the length of the fiber bundle before the formation of the spiral shape is taken as the base (100%), the length of the fiber bundle after the formation of the spiral shape is, for example, 10, 15, 20, 25, 30, 35, 40, 50, 60, 70, 80, or 85%, and may be within the range of any two of the values ​​exemplified here. Note that the "length of the fiber bundle before the formation of the spiral shape" may be measured before the formation of the spiral shape, or it may be measured by dissolving the spiral shape of the fiber bundle after the formation of the spiral shape and fixing both ends. If the ratio of the length of the fiber bundle after the formation of the spiral shape to the length of the fiber bundle before the formation of the spiral shape is greater than or equal to the lower limit, the value of the compressive stiffness LC is reduced. When the ratio of the length of the fiber bundle after forming the spiral shape to the length of the fiber bundle before forming the spiral shape is below the upper limit, the value of the compression power WC increases.

[0053] 2.3 Characteristics of Fiber Bundles 2.3.1 Compressive stiffness Regarding the fiber bundle according to this embodiment, 2.0 cm 2When a compression test is performed at a speed of 1 mm / second from 0 kPa to 49 kPa using the circular planar terminal, the compression rigidity LC is 0.12 or less, preferably 0.11 or less, more preferably 0.10 or less, and even more preferably 0.08 or less. For the fiber bundle, the compression rigidity LC when a compression test is performed may be, for example, 0.12, 0.11, 0.10, 0.09, 0.08, 0.07, 0.06, 0.05, 0.04, 0.03, 0.02, 0.01 or 0, or may be within the range between any two of the values exemplified here. Note that the "compression rigidity LC" is a parameter representing the compression hardness, and the closer the value is to 1, the harder the compression. When the compression is not performed, the value of the compression rigidity LC is 1. When the compression rigidity LC of the fiber bundle is below the upper limit value, it results in a soft touch, and thus the user is less likely to feel discomfort. The compression test can be carried out using a KES-G5 compression tester (manufactured by Kato Tech Co., Ltd.) on a test fiber bundle in which both ends of a plurality (specifically, 20 bundles) of fiber bundles are bundled together, and the measurement can be made with the approximate center of the test fiber bundle aligned with the center of the terminal (such that the approximate center of the test fiber bundle contacts the center of the terminal during compression). Specifically, it can be the value measured under the following conditions. Device: KES-G5 compression tester (manufactured by Kato Tech Co., Ltd.) Compression speed: 1 mm / second Pressing area: 2.0 cm 2 (Circular plane) Load: from 0 kPa to 49 kPa The compression rigidity LC can be decreased, for example, by forming the fiber bundle into a spiral shape, and can be further adjusted by the major diameter and hollow ratio in the fiber cross-section of the artificial hair fiber, the number of artificial hair fibers per fiber bundle, and the pitch and spiral diameter of the spiral shape of the fiber bundle.

[0054] 2.3.2 Compression work rate For the fiber bundle according to the present embodiment, the compression work rate WC when the above compression test is performed is 0.20 N·cm / cm 2 or more, preferably 0.25 N·cm / cm 2 or more, more preferably 0.30 N·cm / cm2 Preferably, the above values ​​are obtained. When a compression test is performed on the fiber bundle, the compression power WC is, for example, 0.20, 0.22, 0.24, 0.26, 0.28, 0.30, 0.32, 0.34, 0.36, 0.38, 0.40, 0.45, or 0.50 N·cm / cm 2 It may be any other value, or it may be within the range of any two of the values ​​exemplified here. Note that "compression power WC" is a parameter that represents how easily something can be compressed; the larger the value, the easier it is to compress. If the compression power WC of the fiber bundle is above the lower limit, it will have a softer feel, and consequently the user will feel less discomfort. Compression power WC can be increased by reducing the specific gravity (i.e., fiber density) of the artificial hair fibers, for example, by providing hollow sections that extend in the longitudinal direction. Furthermore, compression power WC can be adjusted by the outer diameter and hollow ratio in the fiber cross-section of the artificial hair fibers, the number of artificial hair fibers per fiber bundle, and the pitch and diameter of the spiral shape of the fiber bundle.

[0055] 2.4 Method for manufacturing fiber bundles The method for manufacturing fiber bundles according to this embodiment may include a helical shape formation step.

[0056] 2.4.1 Spiral shape formation process In the spiral shape formation process, a fiber bundle containing the artificial hair fibers described above is heated while wrapped around a cylindrical jig to obtain a fiber bundle having a spiral shape. The spiral shape formation process will be described below with reference to Figure 3. As an example, in the spiral shape formation process, a fiber bundle 300 is wrapped around a metal pipe 31, and the metal pipe 31 with the fiber bundle 300 wrapped around it is placed in an oven and heated to obtain a fiber bundle having a spiral shape.

[0057] The cylindrical jig (pipe 31) is not particularly limited as long as it is heat-resistant, and the diameter of the jig can be, for example, 0.5 to 20 mm, preferably 2.0 to 15 mm. The diameter of the jig may also be, for example, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 6.0, 7.0, 8.0, 9.0, 10, 11, 12, 13, 14, 15, or 20 mm, and may be within the range of any two of the values ​​exemplified here.

[0058] The heating temperature and heating time can be appropriately set according to the material constituting the fibers contained in the fiber bundle. Preferably, the heating temperature and heating time are set to a temperature and time at which the resin contained in the fibers shrinks sufficiently. For example, the heating temperature may be 70, 75, 80, 85, 90, 95, 100, 105, or 110°C, and may be within the range of any two of the values ​​exemplified here. For example, the heating time may be 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100 minutes, and may be within the range of any two of the values ​​exemplified here.

[0059] The cooling time and cooling temperature after heating are preferably set to a temperature and time that allows the helical shape formed by heating to be sufficiently memorized. For example, the cooling temperature may be 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50°C, and may be within the range of any two of the values ​​exemplified here, for example, room temperature (1 to 30°C). For example, the cooling time may be 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, or 60 minutes, and may be within the range of any two of the values ​​exemplified here.

[0060] In the spiral shape formation process, the pitch of the fiber bundles after winding them around the pipe 31 is preferably 1.0 to 10.0 mm, and more preferably 2.0 to 8.0 mm. The pitch of the spiral shape of the fiber bundles may be, for example, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, or 10.0 mm, and may be within the range of any two of the values ​​exemplified here.

[0061] In the spiral shape forming process, it is preferable to wrap the fiber bundles around the pipe 31 such that the length X of the fiber bundles in the longitudinal direction of the pipe 31 after wrapping is 50 to 600 mm (preferably 100 to 500 mm or 150 to 300 mm). The length X of the fiber bundles in the longitudinal direction of the pipe 31 after wrapping is, for example, 50, 60, 70, 80, 90, 100, 120, 140, 150, 160, 180, 200, 250, 300, 400, 500, or 600 mm, and may be within the range of any two of the values ​​exemplified here. It is preferable to wrap the fiber bundles around the pipe at equal intervals.

[0062] By setting the conditions in the spiral shape formation process as described above, the characteristics of the resulting fiber bundle, particularly the characteristics related to the spiral shape, can be adjusted to a higher degree, making it easier to obtain fiber bundles with a softer texture.

[0063] 3 Hair accessories The fiber bundles according to this embodiment can be used in hair ornament products. That is, one embodiment of the present invention is a hair ornament product that includes a plurality of the above-described fiber bundles. The hair ornament product according to this embodiment may include 2 to 30 of the above-described fiber bundles, for example, 2, 5, 10, 15, 20, 25, or 30 bundles, and may be within a range between any two of the numbers exemplified here.

[0064] The hair ornament product according to this embodiment can be used by attaching it to the user's hair (natural hair). The method of attachment is not particularly limited, and known methods can be used. One example is tying the hair ornament product to the natural hair. The user can attach 1 to 50 of the hair ornament products according to this embodiment to their head (hair). For example, they can attach 1, 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50 pieces, and the number may be within the range of any two of the numbers exemplified here. Because the hair ornament product according to this embodiment contains the aforementioned fiber bundles, it has a soft texture, and as a result, the user is less likely to feel discomfort. The hair ornament product according to this embodiment is applicable to various styles, but is particularly suitable for Afro Kinky Hair. [Examples]

[0065] The present invention will be described in more detail below based on the following examples. The examples described below are merely representative examples of the present invention and should not be interpreted as narrowing the scope of the invention.

[0066] (Example 1) <Resin composition preparation process> 80 parts by mass of vinyl chloride resin (manufactured by Taiyo Vinyl Chloride Co., Ltd., product name: TH1000), 20% by mass of AS resin (vinyl copolymer resin with 68% by mass of styrene monomer units and 32% by mass of acrylonitrile monomer units (manufactured by Denka Co., Ltd., GR-AT-6S)), 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 material was kneaded using a φ40 mm single-screw extruder to obtain a resin composition in the form of spinning pellets.

[0067] The stabilizer composition used to obtain the resin composition has the following components and composition. • Hydrotalcite compound (Mg4Al2(OH) 12CO3·3H2O) 72.6 parts by mass • Zinc stearate 13.1 parts by mass • Silica (Carplex® #80, manufactured by DSL. Japan Co., Ltd.) 2.2 parts by mass • Dibenzoylmethane 2.3 parts by mass • Dipentaerythritol 0.9 parts by mass • Polyvinyl chloride resin (manufactured by Taiyo Vinyl Chloride Co., Ltd., product name: TH1000) 8.9 parts by mass

[0068] Other additives used to obtain the resin composition are as follows: • Epoxy soybean oil: ADEKA Corporation's "ADEKA Sizer (registered trademark) O-130P" • Phosphorus-based chelating agent: "ADEKA Stab (registered trademark) 1030" manufactured by ADEKA Corporation. • Polyethylene wax: Manufactured by Mitsui Chemicals, Inc.

[0069] <Spinning Process> The obtained pellet-shaped resin composition was spun using a φ40 mm single-screw melt spinning machine. Undrawn yarn was produced from the molten resin discharged from the nozzle by adjusting the discharge rate and winding speed. The nozzle used had a cross-sectional shape with three shallow C-shaped nozzle holes. The obtained fibers had the cross-sectional shape shown in the schematic diagram in Figure 4.

[0070] <Stretching process and heat treatment process> The obtained undrawn yarn (artificial hair fiber before the drawing process) was drawn at 100°C with a draw ratio of 3, and then placed in a heat treatment device and subjected to a heat treatment process at 115°C to obtain artificial hair fiber after the heat treatment process. The relaxation ratio during heat treatment was set to 0.50 to 0.99 times.

[0071] <Adhesion Process> Surface treatment agent A was applied to artificial hair fibers using a roll transfer method. The roll transfer conditions were as follows: the roll radius was 125 mm, the roll was immersed in the solution containing surface treatment agent A up to a height of 20 mm from the bottom end of the roll, and the roll rotation speed was 0.2 to 8 m / min. The amount of surface treatment agent A applied was 0.1% by mass relative to 100% by mass of the artificial hair fiber.

[0072] The surface treatment agent A used contains the following components: Surface treatment agent A: • Oil content: Mineral oil (Mineral Oil manufactured by DKSH Japan Co., Ltd.) Nonionic surfactant: Polyoxyethylene alkyl ether ("Poly(oxyethylene) oleyl ether" manufactured by Nikko Chemicals Co., Ltd.) • Cationic surfactant: Quaternary ammonium salt type cationic surfactant (F-20, manufactured by Yoshimura Oil Chemical Co., Ltd.)

[0073] <Spiral shape formation process> The fibers were cut to a total length of 1300 mm, and 1200 of these cut fibers were taken to create fiber bundles. The fiber bundles were wound onto a 2 mm diameter pipe (made of aluminum) with a winding pitch of 5 mm, so that the length X of the fiber bundle in the longitudinal direction of the pipe after winding was 200 mm (see Figure 3). This was heated in a 95°C oven for 60 minutes, and then cooled at room temperature (1-30°C) for 30 minutes. After cooling, the fiber bundles were removed from the pipe, and spiral-shaped fiber bundles were obtained.

[0074] (Examples 2-9, Comparative Examples 1-3) In the spinning process, the shape of the fiber cross-section and the hollow ratio were adjusted by changing the nozzle. In the spiral shape formation process, the number of fibers to be separated, the size of the jig used for spiral shape formation, and the method of setting the fiber bundle were changed. Except for these changes, fiber bundles according to Examples 2-9 and Comparative Examples 1-3 were prepared in the same manner as Example 1. Examples 1-9 and Comparative Example 1 were artificial hair fibers with a continuous hollow section in the longitudinal direction (i.e., 100% of the total length was hollow), while Comparative Examples 2 and 3 were solid artificial hair fibers without a hollow section. Comparative Examples 1 and 3 did not undergo the spiral shape formation process. The mass per fiber bundle prepared ranged from 3.0 to 13.4 g.

[0075] <Observation of fiber cross-section and hollowness> After the heat treatment process, bundles of fibers cut to appropriate lengths were wrapped with vinyl tape. A fiber bundle for cross-sectional observation was then cut perpendicular to the longitudinal direction using a utility knife to create a fiber cross-section. A laser microscope was used to take cross-sectional photographs of the fibers at a magnification of 400x. (Fiber density) From the obtained images, the volume per unit length was calculated from the outer edge of the fiber in the cross-section (the area enclosed by the outer surface). The volume per unit length was the average value for n (number of fibers) 50. Furthermore, the mass per unit length of the artificial hair fiber was measured, and the fiber density was calculated using the following formula. (Fiber density) = (Mass per unit length) / (Volume per unit length) (Hollow rate) From the obtained images, the area ratio of the hollow portion in the cross-section (hollow ratio) was measured. A controller VK-X150 (manufactured by Keyence Corporation) was used to calculate the hollow ratio. The hollow ratio was the average value for n (number of fibers) 50. In Examples 1 to 9 and Comparative Example 1, hollow portions were present in all fibers. (Hollow ratio) = {(Area enclosed by inner surfaces) / (Area enclosed by outer surfaces)} × 100 (Longest diameter) The major axis of the fiber cross-section was measured from the obtained images. The major axis was taken as the average value for n(n) (number of fibers) of 50. (Fiber thickness) From the obtained images, the fiber thickness in the fiber cross-section was measured. If there was no hollow portion, the fiber thickness was defined as the major axis as described above. If there was a hollow portion, the average value of the shortest distance from the outer surface to the inner surface was calculated for five arbitrary points on the outer surface of the fiber cross-section of a single fiber, and this was then used as the average value for n(number of fibers) 50.

[0076] <Fineness> The fibers, after the heat treatment process, were cut to a length of 50 cm and their mass was measured. The amount in grams per 9000 m length was then calculated.

[0077] <Circumference of the fiber bundle> The circumference of the fiber bundle was calculated based on the spiral diameter (described later) if the fiber bundle had a spiral shape. If the fiber bundle did not have a spiral shape, the minimum circumference was measured when the fiber bundle was bundled so that its cross-section was approximately circular.

[0078] <Pitch and diameter of the spiral shape> One end of the fiber bundle was fixed to a support with a clip, and the pitch and diameter of the spiral shape were measured immediately after the fiber bundle was suspended vertically (see Figure 2). The measurement was performed within 5 minutes of suspending the fiber bundle vertically.

[0079] <Length of fiber bundle> The fiber bundles were laid flat on a plane, and their lengths were measured.

[0080] <Compression Test> The compressive stiffness LC and compressive power WC of fiber bundles were measured using a KES-G5 compression tester (manufactured by Kato Tech Co., Ltd.). Multiple (specifically, 20 bundles) of fiber bundles were prepared, with each end of the bundles tied together. The test bundles were positioned so that the approximate center of each bundle aligned with the center of the terminal (so that the approximate center of each bundle contacted the center of the terminal during compression), and measurements were taken under the following conditions. Equipment: KES-G5 compression tester (manufactured by Kato Tech Co., Ltd.) Compression speed: 1 mm / second Pressure area: 2.0 cm 2 (Circular plane) Load: 0kPa to 49kPa

[0081] <Softness> The softness of the fiber bundles was evaluated by a hair accessory processing technician (with more than 5 years of practical experience) based on the following evaluation criteria. (Evaluation Criteria) ◎: The fiber bundles are soft and there is absolutely no discomfort. ○: The fiber bundles are soft, but there is a slight feeling of discomfort. △: Can't say either way ×: The fiber bundle is stiff.

[0082] [Table 1] [Explanation of symbols]

[0083] 100 Cross-section of hollow fiber 11 Exterior 12. Inner self 13 Joint 14 Joint surface 15 Hollow part 16 Inner protrusion 17 Outer protrusion 200 fiber bundles 21 Support 300 fiber bundles 31. Pipe (Jig)

Claims

1. A fiber bundle containing multiple artificial hair fibers, The fiber density of the aforementioned artificial hair fibers is 0.5 to 1.2 g / cm³. ３ And, Regarding the aforementioned fiber bundle, 2.0 cm ２ A fiber bundle in which the compressive stiffness LC is 0.12 or less when a compression test is performed using a circular planar terminal at a speed of 1 mm / second from 0 kPa to 49 kPa.

2. The fiber bundle according to claim 1, wherein the major axis of the fiber cross-section perpendicular to the longitudinal direction of the artificial hair fiber is 50 to 100 μm.

3. The compression power WC obtained when the aforementioned fiber bundle was subjected to the aforementioned compression test was 0.20 N·cm / cm ２ The fiber bundle described in claim 1 is as described above.

4. The artificial hair fiber comprises a hollow portion extending in the longitudinal direction of the artificial hair fiber, The fiber bundle according to claim 1, wherein the area occupied by the hollow portion in the fiber cross-section perpendicular to the longitudinal direction of the artificial hair fiber is defined as the hollow ratio, and the hollow ratio is 20% or more.

5. The fiber bundle according to claim 1, wherein the fiber bundle has a spiral shape.

6. The fiber bundle according to claim 5, wherein the pitch of the spiral shape of the fiber bundle is 2.0 to 12.0 mm.

7. The fiber bundle according to claim 5, wherein the spiral diameter of the spiral shape of the fiber bundle is 2.0 to 15.0 mm.

8. The fiber bundle according to claim 5, wherein, when the length of the fiber bundle before the formation of the helical shape of the fiber bundle is taken as the reference (100%), the length of the fiber bundle after the formation of the helical shape is 10 to 85%.

9. The fiber bundle according to claim 1, wherein the number of artificial hair fibers contained in one fiber bundle is 300 to 2500.

10. A hair ornament product comprising a plurality of fiber bundles according to any one of claims 1 to 9.

Images