Abstract: Artificial hair fiber having shape memory and shape restoration function, artificial hair fiber having excellent flame resistance, and artificial hair fiber having low gloss appearance are provided. Provided is an artificial hair fiber including a resin composition including at least one polyamide, the artificial hair fiber satisfying at least one of constitutions (1) to (3): (1) the fiber has a modulus of elasticity of 2400 to 3000 N/mm2; (2) the polyamide has a weight average molecular weight Mw of 6.5×104 to 15×104 and the fiber has a modulus of elasticity of 500 to 15000 N/mm2; (3) the fiber has a modulus of elasticity of 500 to 15000 N/mm2 and the resin composition contains 5 to 20 parts by mass of fine particles with respect to 100 parts by mass of the polyamide.

Abstract: An artificial hair fiber is provided that is easy to curl or set. An artificial hair fiber is usually formed and processed within a temperature range from 90 to 150° C. The artificial hair fiber has a storage elastic modulus E? in the formation temperature range. A ratio (E?90/E?150) of a storage elastic modulus E? at a temperature of 90° C. to a storage elastic modulus E? at a temperature of 150° C. is 3 to 20. By this means, the artificial hair fiber can be well curled or transformed, maintaining a desired dynamic characteristic without being melted. The artificial hair fiber can be formed and processed into such a curled hair, so that it is possible to provide a hairpiece product that meets the fashion needs of users.

Abstract: The present invention provides an artificial hair fiber having a good balance between a feel and a curly characteristic. The present invention also provides an artificial hair fiber having a better hackling efficiency and weaving efficiency, a fiber bundle for artificial hair, and a process for producing the same. Artificial hair fibers possess desired properties, the fibers having a flexural rigidity of from 0.001 to 0.01 gf·cm2 or being subjected to crimping in which a crimp wave shape satisfies the following formulae: 0.2 mm?R?3 mm, 1 mm?L?15 mm, (wherein R is a length from the top to the bottom of a crimp wave shape), and (wherein L is a length between the tops (or between the bottoms) of a crimp wave shape).

Abstract: To provide a fiber bundle for artificial hair which has a well balanced combination of properties such as bulkiness, yarn separability, weaving efficiency and hot water-curling efficiency. The fiber bundle for artificial hair is a fiber bundle obtained by crimping fibers (A) having a flexural rigidity of from 0.7 to 2.5 gf·cm2 as measured by the KES method and has a crimp wave shape satisfying the following formula: 1 mm?R?20 mm wherein R is the distance between the top and the bottom of the crimp wave shape. Further, in the fiber bundle for artificial hair, the fibers (A) are vinyl chloride fibers obtained by melt-spinning a vinyl chloride resin composition.

Abstract: To provide fibers for artificial hair prepared under a low nozzle pressure with little gumming, and a fiber bundle for artificial hair having a soft touch close to human hair, while maintaining uniform curling. A fiber bundle for artificial hair comprising fibers (A) having a flexural rigidity of (1.2 to 3.5)×10?2 N·cm2 as determined by the KES method and fibers (B) having a flexural rigidity of (0.5 to 1.0)×10?2 N·cm2 as determined by the KES method, wherein both of the fibers (A) and the fibers (B) are made of vinyl chloride fibers. The fiber bundle for artificial hair, wherein the content of the fibers (A) is from 30 to 90 mass %, the sectional shape of the fibers (A) is at least one selected from the group consisting of Y-, U- and C-shapes, and the sectional shape of the fibers (B) is a spectacled sectional shape.

Abstract: The present invention is to provide a vinyl chloride fiber formed with a vinyl chloride resin composition containing (a) 100 parts by mass of a vinyl chloride resin, (b) 0.2-5.0 parts by mass of a hydrotalcite thermal stabilizer and (c) 0.2-10.0 parts by mass of a epoxy compound. The addition of (c) 0.2-10.0 parts by mass of the epoxy compound to the vinyl chloride resin composition improves a dispersion of the hydrotalcite thermal stabilizer so that a long-run and stable melt spinning is achieved. The vinyl chloride fiber manufactured shows a little color change when the fiber is curled at a curling process.