GRANULAR FILLED POLYTETRAFLUOROETHYLENE AND PROCESS FOR PRODUCING THE SAME

摘要

A granular polytetrafluoroethylene which contains a static-free filler and is obtained by stirring in water a mixture comprising 98 to 50 wt.% polytetrafluoroethylene powder having an average particle diameter of 120 mu m or smaller and 2 to 50 wt.% filler having water repellency imparted thereto by treatment with a phenylsilane coupling agent, in the presence of an organic liquid which forms a liquid/liquid interface with water and of a silicone compound and a surfactant, to granulate the mixture. The granular filled PTFE has a high apparent density, a small average particle diameter, a narrow particle size distribution, excellent powder flowability, and a small charge amount and gives a large molding extremely reduced in coloration.