CORE-SHELL FLUOROPOLYMER DISPERSIONS

摘要

A dispersion of non-melt-processible fluoropolymer particles having an SSG of less than about 2.225 in aqueous medium. The fluoropolymer particles comprise a core of high molecular weight polytetrafluoroethylene having an average melt creep viscosity greater than about 1.5 x 10<10> Pa.s and a shell of lower molecular weight polytetrafluoroethylene or modified polytetrafluoroethylene. The shell has an average melt creep viscosity greater than about 9 x 10<9> Pa.s and comprises about 5 to about 30% by weight of the particles. The fluoropolymer in the dispersion of the invention is fibrillating.