Polyacrylonitrile-based fiber bundle for artificial hair, headdress product containing same, and method for manufacturing same

Abstract

A polyacrylonitrile-based fiber bundle for artificial hair includes polyacrylonitrile-based synthetic fibers A and polyacrylonitrile-based synthetic fibers B. The polyacrylonitrile-based synthetic fibers A have fiber cross-sections with one or more shapes of a C-shape, a figure-6-shape, and a hollow broad bean-shape. The polyacrylonitrile-based synthetic fibers B have fiber cross-sections with one or more shapes of a hollow drop-shape and a drop-shape. The polyacrylonitrile-based synthetic fibers A have a flatness ratio of less than 1.5. The polyacrylonitrile-based synthetic fibers B have a flatness ratio of 1.5 or more. The C-shape, the figure-6-shape, or the hollow bean-shape of the fiber cross-sections has an inscribed circle with a diameter of 15 to 50 μm. The hollow drop-shape of the fiber cross-sections has an inscribed circle with a diameter of more than 0 μm and less than 15 μm. The fiber cross-sections have a thickness of 13 to 40 μm.

1 . A polyacrylonitrile-based fiber bundle for artificial hair, comprising:
 polyacrylonitrile-based synthetic fibers A; and   polyacrylonitrile-based synthetic fibers B,   wherein the polyacrylonitrile-based synthetic fibers A have fiber cross-sections with one or more shapes selected from the group consisting of a C-shape, a figure-6-shape, and a broad bean-shape with a hollow portion,   the polyacrylonitrile-based synthetic fibers B have fiber cross-sections with one or more shapes selected from the group consisting of a drop-shape with a hollow portion and a drop-shape,   the polyacrylonitrile-based synthetic fibers A have a flatness ratio of less than 1.5, and the polyacrylonitrile-based synthetic fibers B have a flatness ratio of 1.5 or more,   the C-shape, the figure-6-shape, or the broad bean-shape with the hollow portion of the fiber cross-sections has an inscribed circle with a diameter of 15 to 50 μm,   the drop-shape with the hollow portion of the fiber cross-sections has an inscribed circle with a diameter of more than 0 μm and less than 15 μm,   fiber cross-sections of the polyacrylonitrile-based fiber bundle for artificial hair have a thickness of 13 to 40 μm,   the polyacrylonitrile-based fiber bundle for artificial hair has a total content of the C-shaped fiber cross-sections, the figure-6-shaped fiber cross-sections, and the broad bean-shaped fiber cross-sections with the hollow portions of 3 to 97%, and   the polyacrylonitrile-based fiber bundle for artificial hair has a total content of the drop-shaped fiber cross-sections with the hollow portions and the drop-shaped fiber cross-sections of 3 to 97%.   
     
     
         2 . The polyacrylonitrile-based fiber bundle for artificial hair according to  claim 1 , comprising one or more selected from the group consisting of polyacrylonitrile-based synthetic fibers A1 having C-shaped fiber cross-sections and polyacrylonitrile-based synthetic fibers A2 having figure-6-shaped fiber cross-sections. 
     
     
         3 . The polyacrylonitrile-based fiber bundle for artificial hair according to  claim 1 , comprising polyacrylonitrile-based synthetic fibers B1 having drop-shaped fiber cross-sections with hollow portions. 
     
     
         4 . The polyacrylonitrile-based fiber bundle for artificial hair according to  claim 1 , the polyacrylonitrile-based fiber bundle for artificial hair has the total content of the drop-shaped fiber cross-sections with the hollow portions and the drop-shaped fiber cross-sections of 3 to 60%. 
     
     
         5 . The polyacrylonitrile-based fiber bundle for artificial hair according to  claim 1 , wherein
 the C-shaped fiber cross-sections have a flatness ratio of 1.0 to 1.2,   the figure-6-shaped fiber cross-sections have a flatness ratio of 1.1 or more and less than 1.5, and   the broad bean-shaped fiber cross-sections with the hollow portion has a flatness ratio of 1.2 to 1.4.   
     
     
         6 . The polyacrylonitrile-based fiber bundle for artificial hair according to  claim 1 , wherein
 the drop-shaped fiber cross-sections with the hollow portions have a flatness ratio of 1.5 to 3.0, and   the drop-shaped fiber cross-sections have a flatness ratio of 2.5 to 3.0.   
     
     
         7 . The polyacrylonitrile-based fiber bundle for artificial hair according to  claim 1 , wherein a single fiber fineness is 35 to 65 dtex. 
     
     
         8 . The polyacrylonitrile-based fiber bundle for artificial hair according to  claim 1 , wherein
 each of the polyacrylonitrile-based synthetic fibers A and the polyacrylonitrile-based synthetic fibers B contains an acrylonitrile-based polymer, and   the acrylonitrile-based polymer comprises:
 a constituent unit derived from acrylonitrile in an amount of 30 to 80 mass %, 
 a constituent unit derived from a halogen-containing monomer in an amount of 20 to 70 mass %; and 
 a constituent unit derived from a sulfonic acid group-containing monomer in an amount of 0 to 5 mass %. 
   
     
     
         9 . A hair ornament product comprising the polyacrylonitrile-based fiber bundle for artificial hair according to  claim 1 . 
     
     
         10 . The hair ornament product according to  claim 9 , wherein the hair ornament product is at least one selected from the group consisting of weaving hair, a wig, a braid, a toupee, a hair extension, and a hair accessory. 
     
     
         11 . A method for producing the polyacrylonitrile-based fiber bundle for artificial hair according to  claim 1 , comprising:
 performing spinning by extruding a spinning solution containing an acrylonitrile-based polymer through a spinning nozzle into a coagulation bath, thereby obtaining coagulated filaments; and   water-washing the coagulated filaments obtained through the spinning,   wherein the spinning nozzle has a C-shaped cross-section with two ends apart from each other,   a discharge amount of the spinning solution per spindle of the spinning nozzle is 0.10 kg/min or more, and   the water-washing is performed at a temperature of 80° C. or lower.   
     
     
         12 . The method for producing the polyacrylonitrile-based fiber bundle for artificial hair according to  claim 11 , wherein the discharge amount of the spinning solution per spindle of the spinning nozzle is 0.10 to 15 kg/min. 
     
     
         13 . The method for producing the polyacrylonitrile-based fiber bundle for artificial hair according to  claim 11 , wherein
 each of the two ends of the C-shape cross-section of the spinning nozzle has a linear portion and a protrusion bulging outward, and   the linear portions of the two ends of the C-shape cross-section are parallel to each other, or one end of the C-shape cross-section is located on a side close to a hollow portion with respect to the other end of the C-shape cross-section.