Patent ID: 9574020
Date: 2017-02-21
CPC Classifications: C08F,C08L

Claim:
1. A method of producing an aqueous dispersion containing at least one fluoropolymer selected from the group consisting of polytetrafluoroethylene and tetrafluoroethylene/perfluoro(alkyl vinyl ether) copolymers, the method comprising polymerizing a fluoromonomer in an aqueous medium in the presence of a fluorosurfactant having a Log POW value of not higher than 3.4 and a polymerization initiator and at least one of a modifying monomer and a chain-transfer agent, the amount of the fluorosurfactant corresponding to 18000 to 500000 ppm of the aqueous medium, wherein the modifying monomer is at least one selected from the group consisting of hexafluoropropylene, chlorotrifluoroethylene, vinylidene fluoride, perfluoropropyl vinyl ether, perfluorobutylethylene, ethylene, perfluoromethyl vinyl ether, perfluorohexylethylene and a fluorinated vinyl ether represented by the formula CF the chain-transfer agent is at least one selected from the group consisting of methane, ethane, propane, butane, chloromethane, dichloromethane, difluoroethane, methanol, ethanol and hydrogen, the amount of the modifying monomer is 0.02-1.49 mol % based on the sum of the amounts of the monomers supplied, and the amount of the chain-transfer agent is 159-3000 ppm based on the sum of the amounts of the monomers supplied.