Patent ID: 7390448

Claim:
A process for dispersion spinning non-melt-processible fluoropolymer fiber comprising the steps of: (a) forming a mixture of an aqueous dispersion of non-melt-processible polytetrafluoroethylene or modified polytetrafluoroethylene particles having an SSG of less than about 2.40, with an aqueous solution of a matrix polymer, said aqueous dispersion containing an aliphatic alcohol ethoxylate nonionic surfactant and containing less than about 0.5 weight % surfactants containing aromatic groups, said aliphatic alcohol ethoxylate having a 20% residuals temperature determined by thermogravimetric analysis (TGA) of less than about 290° C., and said dispersion having a fluorinated surfactant content of less than about 300 ppm; (b) extruding the mixture into a coagulation bath containing a concentration of ions which coagulate the matrix polymer to form an intermediate fiber structure; and (c) sintering the intermediate fiber structure to decompose the matrix polymer and coalesce the non-melt-processible fluoropolymer particles to form said fiber.