PRODUCTION OF TETRAFLUOROETHYLENE/FLUORINATED ALKYL VINYL ETHER COPOLYMER

PURPOSE:To obtain the titled copolymer in good efficiency, by effecting aqueous suspension polymerization at low temperatures with the aid of a specified polymerization initiator and thus making it possible to prevent a marked increase in viscosity of the polymerization system and to improve the dispersibility of the formed polymer. CONSTITUTION:Tetrafluoroethylene and a fluorinated alkyl vinyl ether of formula I (wherein X is H or F, x is 0-4, and y is 0-7), e.g., perfluoro(methyl vinyl ether), are subjected to aqueous suspension polymerization at 0-25 deg.C in the presence of a polymerization initiator of formula II, whrein n is 1-10, in a mixed solvent (volume ratio: 1:1-10:1) consisting of water and a fluorohydrocarbon (e.g., perfluorocyclobutane) or a chlorofluorohydrocarbon (e.g., 1,1,2-trichloro- 1,2,2-trifluoroethane). Because the viscosity of the polymerization system does not increase so much, the polymer formed can be well dispersed in water, its agitation is easy, the yield of copolymer per solvent can be improved markedly to above 0.4 (in weight ratio), the amount of an expensive solvent can be saved, and the separation and recovery of the formed polymer are easy.