Copolymers of tetrafluoroethylene and process for their manufacture

摘要

The invention relates to a process for the copolymerization of tetrafluoroethylene with perfluorinated alkylvinyl ethers of the formula CF3-(CF2)n-O-CF=CF2 wherein n is 1 to 3, in the presence of hexafluoropropene, and the thermoplastic terpolymers so obtained. The copolymerization may be carried out according to the suspension process or the emulsion process in liquid phase in the presence of liquid chain transfer agents. In the presence of hexafluoropropene, the amount of perfluoro(alkyl vinyl) ethers incorporated in the copolymer is considerably increased. The terpolymers in accordance with this invention are distinguished by a number of interesting properties, and are useful for melt processing to shaped articles and as coating materials.