A process for production of high strength, as-spun fiber from optically anisotropic dopes of poly(p-phenyleneterephthalamide) is taught in Blades U.S. Pat. No. 3,767,756. The desirability of improving the fatigue resistance of the filaments produced by the Blades' process was noted in the prior art, e.g., U.S. Pat. No. 4,374,977, and various procedures are disclosed therein purporting to yield fiber with excellent fatigue resistance. An objective of the present invention is the attainment of fiber with superior fatigue resistance to those described in said Blades patent and preferably with only simple process modifciation.
USPTO Backgrounds
USPTO Backgrounds