META-TYPE WHOLLY AROMATIC POLYAMIDE FILAMENTS AND PROCESS FOR PRODUCING SAME

摘要

A process for producing a homogeneous and dense, meta-form wholly aromatic polyamide fiber which comprises: dissolving a meta-form wholly aromatic polyamide comprising m-phenylenediamine isophthalamide units as the main repeating units in an amide compound solvent to prepare a polymer solution; subjecting the polymer solution to a wet spinning step, wherein the polymer solution is ejected in a fiber form through the orifice of a spinneret into a coagulating bath comprising water and an amide compound solvent and containi ng substantially no salts and the resultant fibrous polymer solution which is running is coagulated in the coagulating bath; subjecting the resultant poro us unstretched fiber formed by the coagulation to a stretching step, wherein th e fiber is stretched in a plasticizing stretch bath comprising an aqueous solution of an amide compound solvent; washing the resultant stretched fiber with water; and then subjecting it to a heat treatment (e.g., further stretching the fiber in a stretch ratio of 0.7 to 4.0 while heating it at 25 0 to 400~C).