Patent ID: 9243080
Filing Date: 2016-01-26
CPC Classification: C08F,C08L

Claim Text:
1. A method of producing a polytetrafluoroethylene aqueous dispersion, comprising the steps of: (1) polymerizing a fluoromonomer in an aqueous medium in the presence of a fluorosurfactant and a polymerization initiator to provide an aqueous dispersion containing particles of at least one fluoropolymer selected from the group consisting of polytetrafluoroethylene and melt-processible fluororesins excluding polytetrafluoroethylene; and (2) polymerizing tetrafluoroethylene alone or tetrafluoroethylene and a modifying monomer in an aqueous medium in the presence of the fluoropolymer particles and a polymerization initiator to provide an aqueous dispersion containing polytetrafluoroethylene particles, the fluoropolymer particles having an equivalent weight (EW) of not less than 6,000 and a volume average particle size of not smaller than 0.1 nm but smaller than 20 nm.