PURPOSE: To increase a drying rate of a polybenzazole fiber containing a large amount of water due to washing by water after its coagulation, without forming any deficiency like void, etc., in the fiber, by drying it under a specific condition.
CONSTITUTION: A polybenzazole fiber having a residual water content of 30 wt.% or more is passed continuously through a multiple steps of different drying temperature ranges to dry the fiber until its residual water content of not more than 12wt.%, preferably not more than 2wt.%. The temperature of the each step is set in reference to a maximum drying temperature curve 10 of not forming any void in the fiber and in accordance with the residual water content of the fiber, and a temperature in a following step is set at a higher temperature than that of a previous step. Usually the fiber is dried in a state of multiple winding on a pair of heating rolls to prevent lowering of temperature during transfer between rolls or a pair of rolls for further increase in the rate of drying.
MURASE HIROTAKA
KITAGAWA SUSUMU
JIYAN HAI IMU
CHII CHIYUN CHIYAU
