Process for the thermal stabilization of acrylic fibers

Claim 1

An improved process for the thermal stabilization of an acrylic fibrous material selected from the group consisting of an acrylonitrile homopolymer and acrylonitrile copolymers containing at least about 85 mol percent of acrylonitrile units and up to about 15 mol percent of one or more monovinyl units copolymerized therewith comprising: (a) contacting said fibrous material with a dilute solution of aniline and Group IA metal hydroxide which is provided at an elevated temperature for a residence time of approximately 5 to 30 minutes whereby said fibrous material is rendered capable of undergoing thermal stabilization on a more expeditious basis, (b) removing the excess quantity of said solution adhering to said fibrous material following said contact, and (c) heating said resulting fibrous material in an oxygen-containing atmosphere at a temperature of approximately 200° to 360° C. until a stabilized fibrous material formed which is black in appearance, retains its original configuration substantially intact and which is non-burning when subjected to an ordinary match flame.