METHOD FOR PRODUCING AQUEOUS FLUORINE-CONTAINING POLYMER DISPERSING ELEMENT, AND PURIFIED AQUEOUS FLUORINE-CONTAINING POLYMER DISPERSING ELEMENT

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).