AQUEOUS POLYTETRAFLUOROETHYLENE DISPERSION COMPOSITION AND PROCESS FOR ITS PRODUCTION

摘要

A nonionic surfactant having an average molecular weight of 450 to 800 and a n inorganic/organic ratio of 1.07 to 1.50 is added to an aqueous polytetrafluoroethylene emulsion having a PTFE content of 10 to 50 wt.% obtained by polymerizing tetrafluoroethylene by emulsion polymerization in t he presence of an anionic perfluorocarboxylic acid salt surfactant (APFC), in a n amount of 2 to 20 wt.% based on the PTFE. Water is further added thereto in an amount of 10 to 800 wt.% based on the PTFE to obtain an aqueous PTFE dispersion having a PTFE content of 1 to 40 wt.%. The PTFE is concentrated b y sedimentation. An aqueous PTFE dispersion composition having a high concentration is separated from the supernatant. Thus, an aqueous high- concentration PTFE dispersion composition reduced in APFC concentration is obtained.