Patent ID: 8845938
Filing Date: 2014-09-30
Classification: D01D,D01F,D02J

Abstract:
1. A method of manufacturing a polyacrylonitrile fiber comprising a spinning process in which a spinning dope comprising polyacrylonitrile is spun; a first drawing process; a drying process; and a second drawing process in this order, the method comprising, as the second drawing process, any of the following hot drawing processes (a) to (c): (a) a process of performing, as the second drawing, hot drawing with a plurality of rolls, at least one of which is a hot roll, in the air setting a yarn temperature from a yarn separation point on the hot roll to a first yarn contact point on the subsequent roll to 130° C. or higher, wherein a distance from the yarn separation point on the preheating roll to the first yarn contact point on the subsequent roll is 20 cm or less; (b) a process of performing, as the second drawing, hot drawing with a plurality of rolls, at least one of which is a hot roll, setting a distance from the yarn separation point on the hot roll to the first yarn contact point on the subsequent roll to 20 cm or less; and (c) a process of performing the second drawing in a hot plate drawing zone where a hot plate is placed between two rolls, one of which is a preheating roll arranged forward of the hot plate drawing zone, while the hot plate is positioned so that a start point of contact between the hot plate and a yarn is at a distance of 30 cm or less from the yarn separation point on the preheating roll, and the surface speed of the preheating roll is set to 100 m/min or more.