META-TYPE FULLY AROMATIC POLYAMIDE FIBER HAVING EXCELLENT HIGH-TEMPERATURE PROCESSABILITY AND METHOD FOR PRODUCTION THEREOF

摘要

[PROBLEMS] To provide a novel meta-type fully aromatic polyamide fiber which can prevent the tinting or discoloration of a product and also prevent the generation of any harmful or organic gas even during the processing or use under high temperature conditions. [MEANS FOR SOLVING PROBLEMS] Disclosed is a meta-type fully aromatic polyamide fiber which has a residual solvent content of 1.0% or less, a dry-heat shrinkage rate of 3% or less at 300°C, and a fiber strength of 3.0 cN/dtex or higher. The fiber can be produced by wet-spinning a polymer solution into a fiber, wherein the polymer solution comprises a meta-type fully aromatic polyamide mainly composed of a meta-phenylenediamine isophthalamide skeleton and an amide solvent containing a salt. The method for production of the fiber comprises the following steps (1) to (4): (1) ejecting the polymer solution into a coagulation bath comprising an amide solvent and water and containing a low concentration of a salt to coagulate the polymer solution in the form of a porous linear material (i.e., a fibrous material); (2) stretching the porous linear material in a plastic stretching bath comprising an aqueous solution of an amide solvent; (3) washing the stretched material with water and subsequently thermally treating the washed material in a saturated water vapor atmosphere; and (4) treating the resulting material with dry heat.