Fiber for artificial hair, hair ornament, and method for producing fiber for artificial hair

Abstract

The present invention provides a fiber for artificial hair excellent in texture and lightweight feeling after hot water treatment.　According to the present invention, a fiber for artificial hair is provided. The fiber for artificial hair includes a hollow part extending in the longitudinal direction of the fiber for artificial hair. When fiber for artificial hair is heat-treated at 120°C for 5 minutes to obtain a fiber for artificial hair after 120°C heat treatment, and the fiber for artificial hair after 120°C heat treatment is further immersed in water at 90°C for 30 seconds and then dried to obtain a fiber for artificial hair after 90°C hot water treatment, the color difference ΔE * of the fiber for artificial hair after 90°C hot water treatment is 5 or less.

Description

Artificial hair fiber, hair accessory product, and method for manufacturing artificial hair fiber

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

[0002] Artificial hair is becoming increasingly important as an alternative to human hair in hair accessories such as wigs, hair accessories, 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. Furthermore, depending on the application, artificial hair fibers may be subjected to hot water treatment by immersing them in hot water after braiding or other processing, but the texture (color and gloss) of the artificial hair fibers may deteriorate after the hot water treatment, and this tendency is particularly noticeable in artificial hair fibers having hollow portions.

[0006] The present invention has been made in view of the above circumstances, and provides a fiber for artificial hair that has excellent texture and lightweight feel after hot water treatment.

[0007] According to the present invention, there is provided an artificial hair fiber, which comprises a hollow portion extending in the longitudinal direction of the artificial hair fiber, and the artificial hair fiber is heat-treated at 120°C for 5 minutes to obtain a 120°C heat-treated artificial hair fiber, and the 120°C heat-treated artificial hair fiber is further immersed in 90°C water for 30 seconds and then dried to obtain a 90°C hot water-treated artificial hair fiber, and the color difference ΔE between the 120°C heat-treated artificial hair fiber and the 90°C hot water-treated artificial hair fiber is ＊ The artificial hair fiber is provided, in which the value of the fiber thickness is 5 or less.

[0008] The present inventors have conducted extensive research and have found that the color difference ΔE between the color tone of an artificial hair fiber having a hollow portion when heat-treated under specific conditions and the color tone of an artificial hair fiber when immersed in hot water under specific conditions is ＊ The present inventors have found that by controlling the value of the fiber diameter within a specific range, it is possible to obtain artificial hair fibers that have excellent texture and lightweight feel after hot water treatment, and have completed the present invention.

[0009] Various embodiments of the present invention are exemplified below. The embodiments shown below can be combined with each other. [1] An artificial hair fiber, the artificial hair fiber having a hollow portion extending in the longitudinal direction of the artificial hair fiber, the artificial hair fiber being heat-treated at 120°C for 5 minutes to obtain a 120°C heat-treated artificial hair fiber, and the 120°C heat-treated artificial hair fiber being further immersed in 90°C water for 30 seconds and then dried to obtain a 90°C hot water-treated artificial hair fiber, the color difference ΔE between the 120°C heat-treated artificial hair fiber and the 90°C hot water-treated artificial hair fiber ＊ [2] The color difference ΔL between the artificial hair fiber after the 120°C heat treatment and the artificial hair fiber after the 90°C hot water treatment ＊The artificial hair fiber according to [1], wherein the ratio of the thickness of the hollow portion to the total area of ​​the artificial hair fiber is 3 or less. [3] The artificial hair fiber according to [1] or [2], wherein the hollow portion occupies 5 to 50% of the area of ​​a cross section perpendicular to the longitudinal direction of the artificial hair fiber. [4] The artificial hair fiber according to any of [1] to [3], which contains a vinyl chloride resin. [5] The artificial hair fiber according to any of [1] to [4], wherein the artificial hair fiber has a surface treatment composition on at least a portion of the surface of the synthetic fiber. [6] The artificial hair fiber according to any of [1] to [5], which is for use in a hair accessory product including a braid. [7] A hair accessory product comprising the artificial hair fiber according to any of [1] to [6]. [8] A method for producing artificial hair fibers according to any one of [1] to [7], the method comprising a surface treatment composition application step, a standing step, and a heat treatment step, wherein in the surface treatment composition application step, a surface treatment agent is applied to the surface of synthetic fibers to obtain surface treatment agent-adhered artificial hair fibers, in the standing step, the surface treatment agent-adhered artificial hair fibers are allowed to stand at 30°C or less to obtain artificial hair fibers after standing, and in the heat treatment step, the artificial hair fibers after standing are heat-treated to obtain the artificial hair fibers, the standing step starts when the surface treatment agent is applied to the surface of the synthetic fibers and ends at the start of the heat treatment step, and the standing step lasts for less than 90 minutes.

[0010] The artificial hair fiber according to the present invention has excellent texture and lightness after hot water treatment. The artificial hair fiber according to the present invention is particularly suitable for applications that involve exposure to hot water treatment by immersion in hot water, such as hair accessory products including braids. Furthermore, the hair accessory product according to the present invention has excellent texture and lightness after hot water treatment, and can be used, for example, for braids. According to the method for producing an artificial hair fiber according to one embodiment of the present invention, it is possible to obtain artificial hair fiber that has excellent texture and lightness after hot water treatment.

[0011] Figure 1 shows schematic cross-sectional views 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 with inner and outer protrusions, Figure 1C shows a bilobal cross-section formed by joining two C-shaped portions, Figure 1D shows a trilobal cross-section formed by joining three C-shaped portions, Figure 1E shows a substantially triangular cross-section, and Figure 1F shows a substantially rectangular cross-section.

[0012] The present invention will be described in detail below by illustrating embodiments of the present invention. The present invention is not limited by these descriptions. The features of the embodiments of the present invention described below can be combined with each other. Furthermore, each feature can be an invention independently.

[0013] 1. Artificial Hair Fiber The artificial hair fiber according to the present invention comprises a hollow portion extending in the longitudinal direction of the artificial hair fiber, and the artificial hair fiber is heat-treated at 120°C for 5 minutes to obtain 120°C heat-treated artificial hair fiber, and the 120°C heat-treated artificial hair fiber is further immersed in 90°C water for 30 seconds and then dried to obtain 90°C hot water-treated artificial hair fiber, and the color difference ΔE between the 120°C heat-treated artificial hair fiber and the 90°C hot water-treated artificial hair fiber is ＊ is 5 or less.

[0014] 1.1 Shape of Artificial Hair Fiber The artificial hair fiber according to the present invention has a hollow portion extending in the longitudinal direction of the artificial hair fiber. In the artificial hair fiber according to the present invention, the hollow portion can be continuous for 10 cm or more in the longitudinal direction of the artificial hair fiber. The artificial hair fiber according to the present invention has many advantages, such as being lightweight due to the hollow portion, allowing the desired voluminous hairstyle to be created with a small amount of wear, allowing a wide range of hairstyles to be achieved, including heavy long styles, reducing damage to one's own hair and scalp, and reducing waste and environmental impact.

[0015] An example of a cross section perpendicular to the longitudinal direction of an artificial hair fiber according to one embodiment of the present invention is shown in Figure 1. The cross section perpendicular to the longitudinal direction of an artificial hair fiber according to one embodiment of the present invention can have any one shape selected from a circular shape (Figures 1A and 1B), an elliptical shape, a bilobal shape formed by joining two C-shaped shapes (Figure 1C), a trilobal shape formed by joining three C-shaped shapes (Figure 1D), a quadrilobal shape formed by joining four or more C-shaped shapes, a substantially triangular shape (Figure 1E), a substantially square shape (Figure 1F), and a substantially polygonal shape.

[0016] While the method for producing the artificial hair fiber according to the present invention is not particularly limited, artificial hair fibers are generally obtained by melt-spinning a resin composition for artificial hair fibers. Artificial hair fibers having a hollow portion are formed by melt-extrusion from a nozzle having a single C-shaped nozzle hole or a nozzle having multiple holes, as shown in FIG. 1 of Patent Document 1, for example. Here, the resin composition is at least partially fragmented while passing through the nozzle, but after being discharged from the nozzle hole, the resin composition comes into contact with each other and fuses, forming a hollow portion. The artificial hair fiber according to one embodiment of the present invention can have a bonding surface 14 (shown by a dashed line in FIG. 1) where the resin composition fuses with each other during the melt-extrusion process. Furthermore, the bonding surface 13, which is the region including the bonding surface 14, may have at least one of an inner protrusion 16 protruding toward the hollow portion and an outer protrusion 17 protruding toward the outside of the artificial hair fiber (FIG. 1B). 1B shows a case where the fiber cross section is circular, but even when the hollow portion has another shape, the joint can be provided with at least one of an inner protrusion protruding toward the hollow portion and an outer protrusion protruding toward the outside of the artificial hair fiber. In this way, by providing a protrusion to thicken the joint 13 and increasing the area of ​​the joint surface 14 where the resin compositions are fused together, the joint strength can be improved. The manufacturing method will be described later.

[0017] The artificial hair fiber according to one embodiment of the present invention may have a major diameter of 30 to 300 μm in a cross section perpendicular to the longitudinal direction of the artificial hair fiber, 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.

[0018] The artificial hair fiber according to one embodiment of the present invention preferably has a hollow ratio of 5 to 50%, where the hollow ratio is the area ratio of the hollow portions 15 in a cross section perpendicular to the longitudinal direction of the artificial hair fiber. The hollow ratio may be, for example, 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50%, or may be within a range between any two of the values ​​exemplified here.

[0019] The hollow ratio can be calculated using the following formula: hollow ratio = (area surrounded by the inner surface 12) / (area surrounded by the outer surface 11) × 100. The area surrounded by the outer surface 11 refers to the cross-sectional area when the artificial hair fiber is assumed to have no hollow portions. The hollow ratio can be calculated 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 calculated by the method described in the Examples. By setting the hollow ratio at or above the lower limit, the advantages of having hollow portions can be more reliably obtained. A hollow ratio exceeding the upper limit is undesirable because it leads to an increase in structural defects (an increase in fibers with separated joints or crushed hollow portions), increased rigidity due to an increase in fiber diameter, and a deterioration in tactile feel.

[0020] It is believed that the deterioration in texture after immersion in hot water, which is one of the problems of the present invention, occurs particularly markedly in artificial hair fibers with hollow parts. The reason why artificial hair fibers with hollow parts are prone to deterioration in texture after immersion in hot water is not clear, but it is presumed that this is because artificial hair fibers with hollow parts have a larger distribution of structural strain than solid artificial hair fibers, and are therefore more likely to develop micro-defects such as voids due to immersion in hot water. In conventional technology, it was difficult to suppress the deterioration in texture after immersion in hot water in artificial hair fibers with hollow parts, but according to the present invention, the manufacturing conditions can be set to ΔE ＊ It is believed that by highly adjusting the value of β-hydroxybenzoate so that it is within a specific numerical range, it is possible to suppress the occurrence of minute defects such as voids due to immersion in hot water, and as a result, it is possible to obtain a fiber for artificial hair that is excellent in texture and lightness after hot water treatment.

[0021] 1.2 Materials Constituent of Artificial Hair Fibers 1.2.1 Synthetic Fibers The artificial hair fiber according to one embodiment of the present invention can include a synthetic fiber (substrate), and the artificial hair fiber according to one embodiment of the present invention can include a synthetic fiber and a surface treatment composition on at least a portion of the surface of the synthetic fiber. The synthetic fiber can be composed of a resin composition for artificial hair fibers. The resin contained in the resin composition for artificial hair fibers is not particularly limited and can include at least one of polyamide-based resins, polyester-based resins, vinyl chloride-based resins, AS-based resins (acrylonitrile styrene-based resins), PP resins, PET resins, PE resins, PAN-based resins, and PLA-based resins (polylactic acid-based resins). The artificial hair fiber according to one embodiment of the present invention preferably includes synthetic fibers containing a vinyl chloride-based resin, from the viewpoints of easily achieving a die swelling effect, obtaining a structure with protrusions that increase the area of ​​the bonding surface where the resin compositions are fused together, and easily obtaining an artificial hair fiber having a structure with improved bonding strength. Furthermore, the artificial hair fiber according to one embodiment of the present invention preferably comprises synthetic fibers containing at least one of vinyl chloride resin and AS resin (acrylonitrile styrene resin).

[0022] A vinyl chloride resin according to one embodiment of the present invention may comprise a vinyl chloride polymer containing monomer units (vinyl chloride monomer units) derived from vinyl chloride monomer. The vinyl chloride resin according to the present invention 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 vinyl chloride resin according to the present invention may comprise one type of vinyl chloride polymer, or may comprise two or more types of vinyl chloride polymers.

[0023] The resin composition for artificial hair fibers constituting the synthetic fiber according to one embodiment of the present invention contains 50 to 99 mass% of vinyl chloride resin, preferably 65 to 98 mass%, and more preferably 65 to 97 mass%, per 100 mass% of the resin composition. Specifically, the content may be, for example, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 99 mass%, and may be within a range between any two of the values ​​exemplified herein. The resin composition for artificial hair fibers constituting the synthetic fiber according to one embodiment of the present invention contains 50 to 100 mass parts of vinyl chloride resin, preferably 65 to 100 mass parts, per 100 mass parts of resin contained in the resin composition. Specifically, the content may be, for example, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 99, or 100 mass%, and may be within a range between any two of the values ​​exemplified herein.

[0024] 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 here. 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 here.

[0025] The deterioration of texture after immersion in hot water, which is one of the problems of the present invention, is considered to occur particularly significantly in artificial hair fibers that include synthetic fibers containing resins with low water absorption. Therefore, when the synthetic fibers contain resins with low water absorption, such as vinyl chloride resins or AS resins containing styrene monomer units, ΔE ＊ It is believed that the effect of suppressing deterioration in texture after immersion in hot water by adjusting the amount is particularly pronounced.

[0026] The synthetic fiber according to one embodiment of the present invention may contain other components as needed, such as antistatic agents, heat stabilizers, lubricants, colorants, processing aids, plasticizers, reinforcing agents, UV absorbers, antioxidants, fillers, flame retardants, pigments, initial color improvers, conductivity imparting agents, and fragrances.

[0027] The synthetic fiber according to one embodiment of the present invention preferably contains a colorant. An example of the colorant is carbon black. The resin composition constituting the synthetic fiber according to one embodiment of the present invention may contain 0.1 to 5 parts by mass of a colorant (particularly carbon black) per 100 parts by mass of the resin contained in the resin composition. The content of the colorant (particularly carbon black) per 100 parts by mass of the resin contained in the resin composition may be, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, or 5.0 parts by mass, and may be within a range between any two of the values ​​exemplified here.

[0028] 1.2.2 Surface Treatment Composition The surface treatment composition according to one embodiment of the present invention preferably contains at least one of an oil and a surfactant, and more preferably contains an oil and a surfactant.

[0029] The oil component is not particularly limited, but examples thereof include fatty acid skeleton-containing compounds, polyalkylene glycols, silicones, and liquid paraffin.

[0030] Examples of the fatty acid skeleton-containing compound include fatty acids such as saturated fatty acids such as stearic acid, palmitic acid, myristic acid, lauric acid, and capric acid, and unsaturated fatty acids such as oleic acid; glycerides such as monostearate glyceride, monopalmitic acid glyceride, monomyristic acid glyceride, monolaurate glyceride, monocaprate glyceride, and diglycerides and triglycerides thereof; and organic acid glycerides such as citric acid monoglyceride, succinic acid monoglyceride, and lactic acid monoglyceride.

[0031] Examples of polyalkylene glycols include polyethylene glycol, polypropylene glycol, and polyethylene glycol-polypropylene glycol copolymers. The average degree of polymerization of the polyalkylene glycol is preferably 2 to 50, more preferably 3 to 40, even more preferably 4 to 30, and particularly preferably 4 to 20. The average degree of polymerization of the polyalkylene glycol may be, for example, 2, 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, 30, 35, 40, 45, or 50, or may be within a range between any two of the values ​​exemplified here. When the average degree of polymerization of the polyalkylene glycol is within this range, the artificial hair fiber will have more appropriate slip resistance.

[0032] The oil may be used alone or in combination of two or more. When the surface treatment composition contains an oil, the fiber bundle becomes less slippery and the softness of the fiber bundle can also be improved.

[0033] The surfactant is not particularly limited, but examples thereof include nonionic surfactants, cationic surfactants, and anionic surfactants. Among these, it is preferable to include at least one of a nonionic surfactant and a cationic surfactant.

[0034] Examples of nonionic surfactants 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.

[0035] Examples of cationic surfactants include quaternary ammonium salts having an oxyalkylene group, quaternary ammonium salts having an alkyl group such as alkyltrimethylammonium salts, dialkyldimethylammonium salts, and alkyldimethylethylammonium salts, ammonium salts having an ester bond such as stearoxymethylpyridinium salts, fatty acid triethanolamines, and fatty acid triethanolamine formates, and amine derivatives having an alkyl chain such as polyoxyethylene alkylamines, N-alkylpropyleneamines, and N-alkylpolyethylenepolyamines.

[0036] The surfactant may be used alone or in combination of two or more. The presence of a surfactant tends to further improve softness, slipperiness, combability, and manageability.

[0037] The surface treatment composition according to one embodiment of the present invention may contain other components as needed, provided that the effects of the present invention are not impaired. Examples of such other components include alkyl alkylates, silicone oils (e.g., amino-modified silicones), and mineral oils.

[0038] The artificial hair fiber according to one embodiment of the present invention has a surface treatment composition on at least a part of the surface of the synthetic fiber, which makes it possible to adjust the ease of penetration of hot water, and ΔE ＊ That is, it is thought that ΔE can be adjusted by adjusting the type and amount of each agent contained in the surface treatment composition. ＊ can be adjusted.

[0039] The amount of the surface treatment composition attached to the artificial hair fiber according to one embodiment of the present invention can be 0.05 to 1.0% by mass relative to 100% by mass of the synthetic fiber. The amount of the surface treatment composition attached to 100% by mass of the synthetic fiber 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, or may be within a range between any two of the values ​​exemplified here. When the lower limit of the amount of the surface treatment composition attached to the artificial hair fiber is within this range, the artificial hair fiber bundle will have excellent combability. When the upper limit of the amount of the surface treatment composition attached to the artificial hair fiber is within this range, the artificial hair fiber bundle will have a more appropriate degree of slipperiness.

[0040] 1.3 Characteristics of Artificial Hair Fiber The artificial hair fiber according to the present invention is prepared by heat-treating the artificial hair fiber at 120°C for 5 minutes to obtain 120°C heat-treated artificial hair fiber, which is then immersed in 90°C water for 30 seconds and dried to obtain 90°C hot water-treated artificial hair fiber. The color difference ΔE between the 120°C heat-treated artificial hair fiber and the 90°C hot water-treated artificial hair fiber is ＊ is 5 or less.

[0041] Depending on the application, artificial hair fibers may be subjected to a hot water treatment in which they are immersed in hot water after braiding or other processing. However, the texture (color and luster) of the artificial hair fibers may deteriorate after the hot water treatment, and this tendency is particularly noticeable in artificial hair fibers having hollow portions, for example. Here, the reason why the texture of artificial hair fibers deteriorates after hot water treatment is not clear, but it is thought to be related to the occurrence of minute defects such as voids due to immersion in hot water. In conventional techniques, it has been difficult to prevent the deterioration of texture in artificial hair fibers after immersion in hot water, but according to the present invention, the manufacturing conditions can be set to ΔE ＊ It is believed that by highly adjusting the value of β-hydroxybenzoate so that it is within a specific numerical range, it is possible to obtain a fiber for artificial hair that is less likely to develop micro-defects such as voids due to immersion in hot water, and it is therefore possible to obtain a fiber for artificial hair that is excellent in texture and lightness after hot water treatment.

[0042] Color difference ΔE ＊ The measurement method for ΔE can be as described in the Examples. Specifically, artificial hair fibers are bundled to a length of 400 mm and a mass of 5.1 g to prepare an artificial hair fiber bundle for evaluation. First, the artificial hair fiber bundle for evaluation is heat-treated at 120°C for 5 minutes to obtain 120°C heat-treated artificial hair fibers, and the color tone of the 120°C heat-treated artificial hair fibers is measured using a color tone meter. Here, the 5-minute heating at 120°C can be a dry process in an atmospheric environment. Next, the 120°C heat-treated artificial hair fibers are immersed in 90°C water for 30 seconds and then dried to obtain 90°C hot water-treated artificial hair fibers, and the color tone of the 90°C hot water-treated artificial hair fibers is measured using a color tone meter. Next, ΔE is calculated from the difference in color tone between the 120°C heat-treated artificial hair fibers and the 90°C hot water-treated artificial hair fibers. ＊ , ΔL ＊ Calculate ΔE ＊ , ΔL ＊ The color tone of the artificial hair fiber after heat treatment at 120°C is ＊ =L １２０ ＊ , a ＊ = a １２０ ＊ , b ＊ = b １２０ ＊After hot water treatment at 90°C, the color tone of the artificial hair fiber was ＊ =L ９０ ＊ , a ＊ = a ９０ ＊ , b ＊ = b ９０ ＊ When this is the case, it can be calculated as follows: ＊ =|L ９０ ＊ -L １２０ ＊ | Δa ＊ = | a ９０ ＊ -a １２０ ＊ | Δb ＊ = | b ９０ ＊ -b １２０ ＊ | ΔE ＊ = [(ΔL ＊ ) ２ + (Δa ＊ ) ２ + (Δb ＊ ) ２ 〕 １／２

[0043] In the above measurement method, the step of heat-treating the artificial hair fiber at 120°C for 5 minutes is carried out with the intention of resetting the change in color tone that occurs in the hot water treatment step. Artificial hair fibers (e.g., artificial hair fibers with hollow sections) may experience a change in color tone after undergoing the hot water treatment step, but by performing the heat treatment step at 120°C for 5 minutes, the color tone returns to the same level as before the hot water treatment step. Therefore, according to the above measurement method, even if the artificial hair fiber being evaluated has already undergone a hot water treatment step, the color tone change is reset before the hot water treatment step is performed. Therefore, whether the artificial hair fiber being evaluated is an artificial hair fiber that has undergone a hot water treatment step or not, it is possible to evaluate the change in color difference that may occur in a single hot water treatment step under specific conditions.

[0044] Color difference ΔE between artificial hair fiber after heat treatment at 120°C and artificial hair fiber after hot water treatment at 90°C ＊ is 5 or less, and more preferably 3 or less.＊ is, for example, 0, 1, 2, 3, 4, 5, or may be within a range between any two of the values ​​exemplified here.

[0045] Color difference ΔE ＊ can be adjusted by highly controlling the manufacturing conditions of the artificial hair fiber, for example, by adjusting the type and amount of resin and colorant contained in the resin composition for artificial hair fiber, the draw ratio, the standing time, the heat treatment temperature, etc.

[0046] Color difference ΔL between artificial hair fiber after heat treatment at 120°C and artificial hair fiber after hot water treatment at 90°C ＊ is 3 or less, and more preferably 2 or less. ＊ is, for example, 0, 1, 2, 3, or may be in a range between any two of the values ​​exemplified here.

[0047] Color difference ΔL ＊ can be adjusted by highly controlling the manufacturing conditions of the artificial hair fiber, for example, by adjusting the type and amount of resin and colorant contained in the resin composition for artificial hair fiber, the draw ratio, the standing time, the heat treatment temperature, etc.

[0048] After heat treatment at 120°C, the L of artificial hair fiber １２０ ＊ The L of the artificial hair fiber after heat treatment at 120°C is preferably 25 or less. １２０ ＊ is, for example, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, and may be within a range between any two of the values ​​exemplified here. Generally, artificial hair fibers after 90°C hot water treatment have more micro defects than artificial hair fibers after 120°C heat treatment, and L ９０ ＊ Is, L １２０ ＊ It's often larger.

[0049] After heat treatment at 120°C, the L of artificial hair fiber １２０ ＊can be adjusted by highly controlling the manufacturing conditions of the artificial hair fiber, for example, by adjusting the type and amount of the colorant contained in the resin composition for artificial hair fiber. １２０ ＊ In other words, in the case of dark-colored artificial hair fibers, the deterioration of texture after immersion in hot water is easily noticeable, and ΔE ＊ It is believed that the effect of suppressing deterioration in texture after immersion in hot water by adjusting the amount is particularly pronounced.

[0050] 1.4 Uses of Artificial Hair Fiber The artificial hair fiber according to one embodiment of the present invention can be used for hair decoration products, particularly for hair decoration products including braids. The artificial hair fiber according to one embodiment of the present invention has a hollow portion and has many advantages of having a hollow portion, while also having excellent texture and a lightweight feel after hot water treatment, making it suitable for hair decoration products, particularly for hair decoration products including braids.

[0051] 2. Manufacturing Method of Artificial Hair Fiber Bundle The manufacturing method of the artificial hair fiber of the present invention is not particularly limited. The manufacturing method of the artificial hair fiber according to one embodiment of the present invention can include a surface treatment composition application step, a standing step, and a heat treatment step. In the surface treatment composition application step, a surface treatment agent is applied to the surface of the synthetic fiber to obtain the surface treatment agent-applied artificial hair fiber. In the standing step, the surface treatment agent-applied artificial hair fiber is allowed to stand at 30°C or less to obtain the artificial hair fiber after standing. In the heat treatment step, the artificial hair fiber after standing is heat-treated to obtain the artificial hair fiber. The standing step starts when the surface treatment agent is applied to the surface of the synthetic fiber after drawing and ends at the start of the heat treatment step, and can be less than 90 minutes. The manufacturing method of the artificial hair fiber according to one embodiment of the present invention may include a step of preparing a resin composition for artificial hair fiber, a spinning step, a drawing step, and a gear processing step.

[0052] 2.1 Preparation of Resin Composition for Artificial Hair Fibers In the preparation of a resin composition for artificial hair fibers, raw materials containing resins are mixed to obtain a resin composition for artificial hair fibers. Here, the raw materials include a base resin and may contain other components as necessary. The resin composition for artificial hair fibers is as described above.

[0053] 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 vinyl 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.

[0054] 3.2 Spinning Process In the spinning process, the resin composition for artificial hair fibers can be melt-spun to obtain (undrawn) synthetic fibers. As an example, the resin composition (e.g., pellet compound) can be extruded from a heated cylinder through a nozzle to melt-spin. Conventional known extruders can be used as the extruder, such as a single-screw extruder, a counter-rotating twin-screw extruder, or a conical twin-screw extruder.

[0055] The melt spinning conditions can be appropriately set depending on the type of resin composition so that the resin melts and a bonded structure can be formed. For example, the cylinder temperature can be 150 to 190°C, and the nozzle temperature can be 180±15°C.

[0056] 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).

[0057] The nozzle for melt extrusion of synthetic fibers according to one embodiment of the present invention can be appropriately selected depending on the shape and hollowness of the artificial hair fiber to be obtained. For example, when producing an artificial hair fiber having a circular cross section as shown in Fig. 1A, a nozzle having a C-shaped nozzle hole can be used. When producing an artificial hair fiber having a bilobal cross section with two C-shaped holes joined together as shown in Fig. 1C, a nozzle having two C-shaped nozzle holes can be used. When producing an artificial hair fiber having a trilobal cross section with three C-shaped holes joined together as shown in Fig. 1D, a nozzle having three C-shaped nozzle holes can be used. Furthermore, when producing an artificial hair fiber having a substantially triangular cross section as shown in Fig. 1E, a nozzle having three rod-shaped nozzle holes can be used. When producing an artificial hair fiber having a substantially rectangular cross section as shown in Fig. 1F, a nozzle having four rod-shaped nozzle holes can be used.

[0058] 3.3 Drawing Step In the drawing step, the undrawn synthetic fiber obtained in the melt spinning step is drawn in a drawing machine to obtain a drawn synthetic fiber. As an example, in the drawing step, the undrawn synthetic fiber can be drawn 2 to 5 times at 90 to 110°C in an air atmosphere. The draw ratio is, for example, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, or 5.0 times, or may be within a range between any two of the values ​​exemplified here. By adjusting the drawing conditions, particularly the draw ratio, ΔE ＊ In the present invention, the term "synthetic fiber" refers to a synthetic fiber after spinning, and includes a synthetic fiber before the surface treatment composition is applied.

[0059] 3.4 Surface Treatment Composition Application Step In the surface treatment composition application step, a surface treatment agent is applied to the surface of the synthetic fiber to obtain a surface treatment agent-applied artificial hair fiber. Any application method can be used in the surface treatment composition application step. For example, the surface treatment composition may be applied to the synthetic fiber by a roll transfer method, or the synthetic fiber may be immersed in the surface treatment composition to apply the composition. The amount of the surface treatment composition applied can be adjusted by adjusting the amount charged or the concentration of each component of the surface treatment composition other than the solvent.

[0060] 3.5 Standing Step In the standing step, the artificial hair fiber with the surface treatment agent applied thereto is allowed to stand at 30°C or below to obtain the artificial hair fiber after standing. The standing step begins when the surface treatment agent is applied to the surface of the synthetic fiber (stretched synthetic fiber) and ends at the start of the heat treatment step. Here, the standing step can begin at the end of the surface treatment composition application step, i.e., when the surface treatment agent is applied to the surface of the stretched synthetic fiber. The standing step can also end at the start of the heat treatment step, i.e., when the artificial hair fiber after standing is placed in a heat treatment machine for heat treatment. The temperature in the standing step can be 10 to 30°C, for example, 10, 15, 20, 25, or 30°C, or it can be within a range between any two of the values ​​exemplified here. The time from the start to the end of the standing step (standing time) is preferably less than 90 minutes. The standing time is, for example, 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, or 85 minutes, and may be within a range between any two of the values ​​exemplified here. By adjusting the standing conditions, particularly the standing time, ΔE ＊ It is possible to adjust ΔE ＊ Although the mechanism by which this can be adjusted is not clear, it is presumed to be related to the occurrence of relaxation of orientation after the stretching step while the film is left standing at a relatively low temperature (for example, 10 to 30°C).

[0061] 3.6 Heat Treatment Step In the heat treatment step, the artificial hair fiber is heat-treated after standing to obtain an artificial hair fiber. For example, in the heat treatment step, the artificial hair fiber is heat-treated in an air atmosphere at 90 to 120°C after standing, causing the entire length of the fiber to thermally shrink so that the relaxation rate after heat treatment is 0.50 to 0.99 times, thereby obtaining an artificial hair fiber (after heat treatment) with the desired fineness. The relaxation rate during heat treatment is calculated by dividing the rotational speed of the take-up roller during annealing by the rotational speed of the delivery roller during annealing. The heat treatment temperature is, for example, 90, 95, 100, 105, 110, 115, or 120°C, and may be within a range between any two of the values ​​exemplified here. The heat treatment time can be 3 to 10 minutes. The heat treatment time is, for example, 3, 4, 5, 6, 7, 8, 9, or 10 minutes, and may be within a range between any two of the values ​​exemplified here. The start of the heat treatment step can be the time when the artificial hair fiber starts to be exposed to an atmosphere at a set temperature, for example, 90°C or higher. The heat treatment device used in the heat treatment step is preferably preheated to the heat treatment temperature, and the heat treatment step can be started when the artificial hair fiber is placed in an oven preheated to the set temperature. By adjusting the heat treatment conditions, particularly the heat treatment temperature, it is possible to reduce ΔE ＊ can be adjusted.

[0062] 3.7 Gear Processing Step The method for producing artificial hair fibers according to one embodiment of the present invention 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 gears used in this gear processing step, the shape of the gear waves, and the number of gear fractions are not particularly limited. In this gear processing step, the shape of the resulting artificial hair fibers 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 account the fiber material and fineness. These processing conditions are not particularly limited, but as an example, the depth of the gear wave grooves can be 0.2 mm to 6 mm, preferably 0.5 mm to 5 mm, the gear surface temperature can be 30°C to 100°C, preferably 40°C to 80°C, and the processing speed can be 0.5 to 10 m / min, preferably 1.0 m / min to 8.0 m / min.

[0063] 3.8 Other Steps The method for producing artificial hair fibers according to one embodiment of the present invention may include other steps as necessary, such as a processing step to form a hair accessory product (specifically, a processing step such as braiding) or a hot water treatment step of immersion in hot water. In the present invention, artificial hair fibers include artificial hair fibers after spinning, and encompass artificial hair fibers before the drawing step, after the drawing step, before the surface treatment composition application step, after the surface treatment composition application step, before the standing step, after the standing step, before the heat treatment step, after the heat treatment step, before the gear processing step, after the gear processing step, before the processing step to form a hair accessory product, after the processing step to form a hair accessory product, before the hot water treatment step of immersion in hot water, and after the hot water treatment step of immersion in hot water.

[0064] 4. Artificial Hair Fiber Bundle and Hair Accessory Product An artificial hair fiber bundle according to one embodiment of the present invention comprises the above-mentioned artificial hair fiber. Also, a hair accessory product according to one embodiment of the present invention comprises the above-mentioned artificial hair fiber bundle.

[0065] The artificial hair fiber according to the present invention can be used in hair accessory products. Examples of hair accessory products include wigs, hairpieces, braids, hair extensions, doll hair, hair wigs, false hair, and hair bands. Hair accessory products obtained from the artificial hair fiber according to the present invention have hollow portions and exhibit excellent texture and lightness after hot water treatment. Hair accessory products obtained from the artificial hair fiber according to one embodiment of the present invention have many advantages, including hollow portions, excellent texture and lightness after hot water treatment, lightweight, the ability to create the desired voluminous hairstyle with a small amount of application, the ability to achieve a wide range of hairstyles, including heavy long styles, reduced damage to natural hair and scalp, reduced waste and environmental impact, and minimal change in texture after processing, allowing customers to achieve the desired finish. The hair accessory product according to one embodiment of the present invention, having the above characteristics, can be applied to a variety of styles, but is particularly suitable for braids, including braids and twists.

[0066] The present invention will be described in more detail below based on examples, but the present invention should not be construed as being limited to these examples.

[0067] Example 1 Preparation of Resin Composition for Artificial Hair Fibers 100 parts by mass of vinyl chloride resin (manufactured by Taiyo PVC Co., Ltd., product name: TH1000), 0.5 parts by mass of carbon black (manufactured by Mitsubishi Chemical Corporation, product name: #950 Carbon), and 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) 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)CO ３ ・3H ２ O) 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.

[0068] <Spinning step> The obtained pellet-shaped resin composition for artificial hair fibers was spun using a φ40 mm single-screw melt spinning machine. The discharge rate and winding speed were adjusted to produce undrawn yarn from the molten resin discharged from the nozzle. The nozzle used had three C-shaped nozzle holes in cross section. The cylinder temperature and nozzle temperature of the spinning machine were set to 140 to 190°C.

[0069] <Drawing step, surface treatment composition application step, standing step, and heat treatment step> The obtained undrawn yarn (undrawn synthetic fiber) was drawn in a drawing machine at 100°C at a draw ratio of 3 to obtain a drawn synthetic fiber. The drawn synthetic fiber was immersed in a surface treatment composition containing polyethylene glycol (manufactured by Aoki Oil & Fats Co., Ltd., product name: PEG-200, average degree of polymerization 4) and a quaternary ammonium salt-type cationic surfactant (manufactured by Yoshimura Oil Chemical Co., Ltd., product name: F-20) to adhere the surface treatment composition to the drawn synthetic fiber, thereby obtaining a surface treatment agent-applied artificial hair fiber. The surface treatment agent-applied artificial hair fiber was allowed to stand at room temperature (23°C) for 10 minutes from the time when the surface treatment composition adhered to the drawn artificial hair fiber, and an artificial hair fiber was obtained after standing. After leaving the fiber for artificial hair at rest for 10 minutes, the fiber was placed in a heat treatment device and the heat treatment was started at 115°C. After the heat treatment, the fiber for artificial hair was obtained. The heat treatment device was preheated, and the fiber for artificial hair was placed in a furnace with an atmospheric temperature of 115°C. The relaxation rate during the heat treatment was set to 0.50 to 0.99 times. The relaxation rate during the heat treatment is a value calculated by dividing the rotational speed of the take-up roller during annealing by the rotational speed of the delivery roller during annealing.

[0070] (Examples 2 to 10, Comparative Examples 1 to 3) Artificial hair fibers were obtained in the same manner as in Example 1, except that the composition of the resin composition for artificial hair fibers, the type of nozzle, the draw ratio, the standing time, and the heat treatment temperature were changed. In Example 10, a vinyl copolymer resin containing 68% by mass of styrene monomer units and 32% by mass of acrylonitrile monomer units (manufactured by Denka Co., Ltd., product name: GR-AT-6S) was used as the AS-based resin. In Examples 8, 9, 10, and Comparative Example 2, nozzles having different nozzle hole cross-sectional shapes were used to adjust the hollow ratio.

[0071] The obtained artificial hair fibers were evaluated by the following method. <Hollow ratio> The artificial hair fibers were cut to an appropriate length, and the resulting bundle was wrapped in vinyl tape. The bundle was then cut perpendicular to the longitudinal direction with a cutter knife to prepare a cross section, which was then observed. A cross-sectional photograph of the fiber was taken at 400x magnification using a laser microscope, and the area ratio of hollow portions in the cross section (hollow ratio) was measured. Hollow ratio = area surrounded by the inner surface / area surrounded by the outer surface. The hollow ratio was calculated using a controller VK-X150 manufactured by Keyence Corporation. The hollow ratio was taken as the average value for 50 samples.

[0072] <L before immersion ＊ value, ΔE ＊ , ΔL ＊ > The artificial hair fibers of the Examples and Comparative Examples were bundled to a length of 400 mm and a mass of 5.1 g to prepare an artificial hair fiber bundle for evaluation. First, the artificial hair fiber bundle for evaluation was heat-treated at 120°C for 5 minutes in an air atmosphere in a Perfect Oven (PH302, manufactured by ESPEC Corporation), to obtain 120°C heat-treated artificial hair fibers. The color tone of the 120°C heat-treated artificial hair fibers was measured using a color tone meter (CM-36dGV, manufactured by Konica Minolta). Next, the 120°C heat-treated artificial hair fibers were immersed in 90°C water for 30 seconds and then dried to obtain 90°C hot water-treated artificial hair fibers. The color tone of the 90°C hot water-treated artificial hair fibers was measured using a color tone meter (CM-36dGV, manufactured by Konica Minolta Corporation). From the difference in color tone of the artificial hair fiber after heat treatment at 120°C and the color tone of the artificial hair fiber after hot water treatment at 90°C, ΔE ＊ , ΔL ＊ was calculated. ＊ , ΔL ＊ The color tone of the artificial hair fiber after heat treatment at 120°C is ＊ =L １２０ ＊ , a ＊ = a １２０ ＊ , b ＊ = b １２０ ＊ After hot water treatment at 90°C, the color tone of the artificial hair fiber was ＊ =L ９０ ＊ , a ＊ = a ９０＊ , b ＊ = b ９０ ＊ When this is the case, it can be calculated as follows: ＊ =|L ９０ ＊ -L １２０ ＊ | Δa ＊ = | a ９０ ＊ -a １２０ ＊ | Δb ＊ = | b ９０ ＊ -b １２０ ＊ | ΔE ＊ = [(ΔL ＊ ) ２ + (Δa ＊ ) ２ + (Δb ＊ ) ２ 〕 １／２

[0073] The artificial hair fiber bundle for evaluation according to Example 1 was subjected to color measurement once using the above-mentioned measurement method (i.e., the artificial hair fiber was heat-treated at 120°C for 5 minutes, immersed in water at 90°C for 30 seconds, and then dried), and the same artificial hair fiber bundle for evaluation was subjected to color measurement again using the above-mentioned measurement method. ＊ The color tone of the artificial hair fiber bundle for evaluation according to Comparative Example 1 was also measured once by the above-mentioned method, and then the color tone of the same artificial hair fiber bundle for evaluation was measured again by the above-mentioned method. ＊ The result of the second measurement was the same as that of the first measurement.

[0074] <Texture> A braided structure was prepared using the artificial hair fibers of the Examples and Comparative Examples, each having a length of 400 mm and a mass of 5.1 g, and then the braided structure was immersed in water at 90°C for 30 seconds. Next, the braided structure was removed from the water, and the surface of the braided structure was lightly rubbed three times to wipe off the water. The braided structure was then left to dry naturally at room temperature (25°C) for 24 hours or more, after which the color and luster were evaluated visually and by touch. Ten hair fiber treatment technicians (with at least 5 years of work experience) visually and by touch and evaluated the texture using two ranks: "good texture" or "poor texture," according to the following criteria: A: 9 or more people rated the texture as good; B: 5 to 8 people rated the texture as good; C: 1 to 4 people rated the texture as good; D: 0 people rated the texture as good

[0075] <Lightweight Feeling> A braided structure was prepared using the artificial hair fibers of the Examples and Comparative Examples, each having a length of 400 mm and a mass of 5.1 g, and then the braided structure was immersed in water at 90°C for 30 seconds. Next, the braided structure was removed from the water, and the surface of the braided structure was lightly rubbed three times to wipe off the water. The braided structure was then left to dry naturally at room temperature (25°C) for 24 hours or more, and evaluated for its lightweight feel when touched with the hand. Ten hair fiber treatment technicians (with at least 5 years of work experience) evaluated the braided structure using two ranks: "feels lightweight" or "does not feel lightweight," and the evaluation was based on the following criteria: A: 9 or more people rated it as feeling lightweight; B: 5 to 8 people rated it as feeling lightweight; C: 1 to 4 people rated it as feeling lightweight; D: 0 people rated it as feeling lightweight.

[0076]

[0077] 100: Cross section of artificial hair fiber, 11: Outer surface, 12: Inner surface, 13: Joint portion, 14: Joint surface, 15: Hollow portion, 16: Inner protrusion, 17: Outer protrusion

Claims

1. A fiber for artificial hair, wherein the fiber for artificial hair has a hollow portion extending in the longitudinal direction of the fiber for artificial hair, the fiber for artificial hair is heat-treated at 120° C. for 5 minutes to obtain a fiber for artificial hair after the heat treatment at 120° C., and further, after the fiber for artificial hair after the heat treatment at 120° C. is immersed in water at 90° C. for 30 seconds and then dried to obtain a fiber for artificial hair after the heat treatment with hot water at 90° C., the color difference ΔE ＊ between the fiber for artificial hair after the heat treatment at 120° C. and the fiber for artificial hair after the heat treatment with hot water at 90° C. is 5 or less.

2. The color difference ΔL between the fiber for artificial hair after the heat treatment at 120°C and the fiber for artificial hair after the hot water treatment at 90°C ＊ is 3 or less, and the fiber for artificial hair according to claim 1.

3. The artificial hair fiber according to claim 1 or 2, wherein the hollow portion occupies an area of 5 to 50% in a cross-section perpendicular to the longitudinal direction of the artificial hair fiber.

4. The artificial hair fiber according to claim 1 or 2, comprising a vinyl chloride-based resin.

5. The artificial hair fiber according to claim 1 or 2, wherein the artificial hair fiber has a surface treatment composition on at least a part of the surface of a synthetic fiber.

6. The artificial hair fiber according to claim 1 or 2, which is for a hair decoration product including a blade.

7. A hair decoration product comprising the artificial hair fiber according to claim 1 or 2.

8. A method for manufacturing the artificial hair fiber according to claim 1 or 2, the manufacturing method including a surface treatment composition adhesion step, a standing step, and a heat treatment step, in the surface treatment composition adhesion step, a surface treatment agent is adhered to the surface of a synthetic fiber to obtain a surface treatment agent-adhered artificial hair fiber, in the standing step, the surface treatment agent-adhered artificial hair fiber is left standing at 30°C or lower to obtain a post-standing artificial hair fiber, in the heat treatment step, the post-standing artificial hair fiber is heat-treated to obtain the artificial hair fiber, the standing step starts when the surface treatment agent adheres to the surface of the synthetic fiber and ends at the start of the heat treatment step, and the standing step is less than 90 minutes.

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