Abstract: A fluorine-containing elastomer having excellent low temperature resistance and oil resistance comprises ethylene units (E) and fluorovinyl ether units (FV) having the formula CF.sub.2 .dbd.CFOX (X represents a C.sub.1 -C.sub.9 perfluoroalkyl group which can have one or more ether bond) at a molar ratio of (E) to (FV) of 95:5 to 30:70 and at a total content of (E) and (FV) of at least 70 mole %.

Abstract: Terpolymers of tetrafluoroethylene and ethylene essentially consist of components of from 40 to 60 mole % of tetrafluoroethylene, 40 to 60 mole % of ethylene and 0.1 to 10 mole % of fluorovinyl ether component having the formulaCF.sub.2 .dbd.CF--O--(CF.sub.2).sub.n --COXwherein X is selected from the group consisting of F, OH, OR.sup.1 and NR.sup.2 R.sup.3 and R.sup.1 represents a C.sub.1 -C.sub.10 alkyl group and R.sup.2 and R.sup.3 respectively represent hydrogen atom or R.sup.1 and n represents an integer of 1 to 10.Said terpolymer has a volumetric flow rate of 10 to 500 mm.sup.3 /sec. defined in the specification.The terpolymers of tetrafluoroethylene and ethylene are produced by copolymerizing tetrafluoroethylene and ethylene with a molar ratio of C.sub.2 F.sub.4 /C.sub.2 H.sub.4 being kept essentially higher than 40/60 in the reactor in the presence of a small amount of a perfluoroalkyl vinyl monomer having the formulaCF.sub.2 .dbd.CF--O--(CF).sub.n --COXwherein X and n are defined above.

Abstract: A fluorocopolymer is produced by copolymerizing a fluoroolefin and cyclohexyl vinyl ether in the presence of a polymerization initiator at -30.degree. to +150.degree. C. at a molar ratio of the fluoroolefin to cyclohexyl vinyl ether in charge of 95:5 to 5:95.