Vinylidene fluoride resin fiber and process for producing the same

摘要

A vinylidene fluoride resin fiber having an increased tensile strength is obtained by spinning by melt-extrusion of a vinylidene fluoride resin having a large polymerization degree under the conditions of a small extrusion rate and a large draft ratio into a small diameter of spun fiber. The thus obtained fiber is characterized by having no crystal melting point based on the vinylidene fluoride chains at a temperature below 178 DEG C., and having a mean crystal length in the molecular chain direction of 200 A or longer and a birefringence of 30x10-3 or larger.