Patent ID: 8470942

Claim:
A method for producing a melt-moldable tetrafluoroethylene copolymer comprising: radical suspension-polymerizing tetrafluoroethylene and perfluoro(alkyl vinyl ether) in an aqueous medium in the presence of a radical polymerization initiator, at least one chain transfer agent selected from the group consisting of methane, ethane, a hydrochlorocarbon, a hydrofluorocarbon and a hydrochlorofluorocarbon, and 3 to 32.1 ppm of a fluoroemulsifier, based on the total mass of the aqueous medium, by charging the perfluoro(alkyl vinyl ether) all at once at the initiation of the polymerization, wherein said melt-moldable tetrafluoroethylene copolymer comprises repeating units (a) based on tetrafluoroethylene and repeating units (b) based on perfluoro(alkyl vinyl ether), wherein the amount of the repeating units (a) is from 97.4 to 99.5 mass % based on the total mass of the repeating units (a) and the repeating units (b), and the amount of the repeating units (b) is from 0.5 to 2.6 mass % based on the total mass of the repeating units (a) and the repeating units (b), the melting point of said melt-moldable tetrafluoroethylene copolymer is from 320 to 335° C., and the volume flow rate of said melt-moldable tetrafluoroethylene copolymer is from 0.1 to 1000 mm 3 /s.