PROCÉDÉ DE FABRICATION D'UN ÉLÉMENT DE DISPERSION AQUEUSE DE POLYMÈRE CONTENANT DU FLUOR ET ÉLÉMENT DE DISPERSION AQUEUSE DE POLYMÈRE CONTENANT DU FLUOR PURIFIÉE

摘要

An object of the present invention is to provide methods for preparing a fluoropolymer aqueous dispersion that allow efficient removal of iron ions from fluoropolymer aqueous dispersions, and purified fluoropolymer aqueous dispersions. The present invention relates to a method for preparing a fluoropolymer aqueous dispersion, including: step (A) of preparing a fluoropolymer aqueous dispersion comprising a fluoropolymer having at least one selected from the group consisting of - SO 2 Y and -COOR (wherein Y is a halogen, and R is a C1 to C4 alkyl) by emulsion polymerization; step (B) of heating the fluoropolymer aqueous dispersion to 50°C or higher; and step (C) of contacting the fluoropolymer aqueous dispersion with an ion exchange resin for cation exchange after step (B), thereby providing a purified fluoropolymer aqueous dispersion, the fluoropolymer aqueous dispersion being adjusted to pH 7 or lower from the end of the polymerization in step (A) to the end of step (C).