PURPOSE: To enable economic and efficient production of a copolymer of excellent dynamic properties, heat resistance, solvent resistance and chemical resistance by effecting the copolymerization of ethylene and tetrafluoroethylene using a specific polymerization initiator and a catalyst, as the concentration of the copolymer is kept in a certain range.
CONSTITUTION: In the production of ethylene-tetrafluoroethylene copolymer by polymerization of the monomers in a medium, a hydrofluoro-carbon of 3 to 10 carbon atoms (where 1≤ hydrogen atom number ≤ fluorine atom number) is used as a polymerization catalyst, a part of the copolymer formed is taken out, while the starting monomers are continuously or intermittently fed so that the copolymer concentration is kept at 0.01 to 0.15g/cc of the hydrofluorocarbon during the polymerization thereby the objective ethylene- tetrafluoroethylene copolymer. The copolymerization is effected at 40/60-90/10 tetrafluoroethylene/ethylene feed molar ratio in a hydrofluorocarbon.
TAKAKURA TERUO
MIYAKE HARUHISA
