公开(公告)号：US20220235156A1

公开(公告)日：2022-07-28

申请号：US17659182

申请日：2022-04-14

Applicant: AGC INC.

Inventor： Shinya HIGUCHI ,  Masahiro TAKAZAWA ,  Yingwei LAI ,  Shiro EBATA ,  Takehiro KOSE

IPC: C08F114/26

Abstract: To provide a method for producing an aqueous dispersion of polytetrafluoroethylene, whereby formation of fluorinated oligomers as byproducts is little and CFT of a coating film to be formed is large.
A method for producing an aqueous dispersion of polytetrafluoroethylene, which comprises step A1 of polymerizing a non-fluorinated monomer in an aqueous medium to obtain a solution 1 containing a polymer comprising units based on said non-fluorinated monomer, step A2 of conducting polymerization of tetrafluoroethylene in said solution 1 without substantially adding a surfactant to said solution 1, to obtain an aqueous emulsion containing polytetrafluoroethylene particles, and step A3 of adding a nonionic surfactant to said aqueous emulsion, and then concentrating said aqueous emulsion to obtain an aqueous dispersion of polytetrafluoroethylene, wherein the amount of said non-fluorinated monomer used is at most 200 mass ppm to the amount of said tetrafluoroethylene supplied to the polymerization system.