AQUEOUS DISPERSION OF POLYTETRAFLUOROETHYLENE AND PROCESS FOR PRODUCING THE SAME

摘要

An aqueous dispersion of polytetrafluoroethylene (PTFE) comprising from 55 to 70 mass% of PTFE fine particles having an average particle diameter of from 0.1 to 0.5 µm, from 0.0001 to 0.02 mass%, based on PTFE, of a specific C8 fluorine-containing carboxylic acid salt (APFO) such as ammonium perfluorooctanoate, from 1 to 20 mass%, based on PTFE, of a specific nonionic surfactant and from 0.01 to 0.3 mass%, based on PTFE, of a specific C 5-7 fluorine-containing carboxylic acid salt such as ammonium perfluorohexanoate. The aqueous dispersion of PTFE has excellent properties which can form crack-resistant coatings which do not undergo coloration during baking or form problematic ionic impurities by improving the friction stability of aqueous PTFE dispersions even at APFO concentrations without viscosity increase.