| 摘要 |
To an aqueous PTFE polymer emulsion having a PTFE content of from 10 to 50 mass% obtained by emulsion polymerization of tetrafluoroethylene in the presence of an anionic perfluorocarboxylate surfactant (APFC), from 2 to 20 mass%, based on the mass of PTFE, of a nonionic surfactant having an average molecular weight of from 450 to 800 and an inorganic/organic property ratio of from 1.07 to 1.50 and from 10 to 800 mass%, based on the mass of PTFE, of water are added to obtain an aqueous PTFE dispersion having a PTFE content of from 1 to 40 mass% of PTFE, and then PTFE is concentrated by sedimenting the PTFE and separating a PTFE-rich aqueous dispersion composition from the supernatant. According to the present invention, a PTFE-rich aqueous dispersion composition having a low APFC concentration can be obtained. |
