Abstract: Tetrafluoroethylene-perfluorovinylether copolymer having a specific melt viscosity of 30.times.10.sup.4 to 200.times.10.sup.4 poises at 372.degree. C., which comprises 99% to 90% by weight of tetrafluoroethylene and 1% to 10% by weight of perfluoro(ethyl vinyl ether) can produce a film or sheet having good resistance to flex fatigue by molding.

Abstract: By using salicylaldoimino copper complex having the following formula as a cross-linking agent for a fluorine-containing elastomer containing at least one of iodine and bromine in the molecule, a vulcanization product with an improved heat resistance can be obtained and generation of harmful substances such as methyl iodine, methyl bromine, etc.

Abstract: An acrylic elastomer capable of giving a vulcanization product having a distinguished tensile strength and a good stretching even by cross-linking with an organic peroxide can be obtained by using an organic peroxide having a non-conjugated double bond as a polymerization initiator in polymerization of at least one of (a) alkyl acrylates having an alkyl group of 1 to 8 carbon atoms and (b) alkoxyalkyl acrylates having an alkoxylalkyl group of 2 to 8 carbon atoms.

Abstract: A fluorine-containing elastomer capable of giving a primary vulcanization product with a good permanent set through peroxide vulcanization is produced by homopolymerization or copolymerization of a fluorine-containing olefin having 2 to 8 carbon atoms in the presence of an iodine and bromine-containing compound represented by the general formula RBrnIm, wherein R represents a fluorohydrocarbon group, a chlorofluorohydrocarbon group, a chlorohydrocarbon group or a hydrocarbon group, and n and m each are integers of 1 and 2, and a small amount of perfluoro(vinylether) compound having a general formula of CF.sub.2 .dbd.CFO[CF.sub.2 CF(CF.sub.3)O]m(CF.sub.2)nX, wherein X is a bromine atom or an iodine atom and m and n each are 1, 2 or 3.

Abstract: An acrylic elastomer capable of giving a vulcanization product having a distinguished tensile strength and a good stretching even by cross-linking with an organic peroxide can be obtained by using an organic peroxide having a non-conjugated double bond as a polymerization initiator in polymerization of at least one of (a) alkyl acrylates having an alkyl group of 1 to 8 carbon atoms and (b) alkoxyalkyl acrylates having an alkoxyalkyl grouop of 2 to 8 carbon atoms.

Abstract: A fluorine-containing elastomer capable of giving a primary vulcanization product with a good permanent set through peroxide vulcanization is produced by homopolymerization or copolymerization of a fluorine-containing olefin having 2 to 8 carbon atoms in the presence of an iodine and bromine-containing compound represented by the general formula RBrnIm, wherein R represents a fluorohydrocarbon group, a chlorofluorohydrocarbon group, a chlorohydrocarbon group or a hydrocarbon group, and n and m are integers of 1 and 2, and a small amount of perfluoro(unsaturated compound) which is iodotrifluoroethylene, perfluoro(bromoalkylvinylether) or perfluoro(iodoalkylvinylether).

Abstract: This invention relates to a fluorine containing polymer as well as a curable composition containing the polymer and an organic peroxide. The fluorine containing polymer consists of a copolymer of (1) 3-bromoperfluoropropyl perfluorovinyl ether or 2-bromoperfluoropropyl perfluorovinyl ether, and (2) a fluorine containing monomer of 2 to 8 carbon atoms copolymerizable with said perfluoropropyl perfluorovinyl ether, the content of said perfluoropropyl perfluorovinyl ether in said copolymer being less than 5 mol %.

Abstract: A peroxide-vulcanizable, fluorine-containing elastomer having distinguished processability, vulcanization characteristics and physical properties of vulcanized products can be obtained by polymerization of fluorine-containing olefins having 2 to 8 carbon atoms in the presence of a bromine or iodine-containing aromatic or perfluoroaromatic compound, polysubstituted with (1) bromine atoms or bromoalkyl groups (2) iodine atoms or iodoalkyl groups.

Abstract: A useful carbonyl compound as an intermediate for producing perfluoro(lower alkyl vinyl ether) can be obtained by thermally decomposing a polyether compounds represented by the following general formulas at a temperature of about 180.degree. C.-about 400.degree. C. in the presence of an activated carbon catalyst:RfO(CF.sub.2 CF.sub.2 O).sub.a (CF.sub.2 O).sub.b (O).sub.c Rf',orRfO(CFXCF.sub.2 O).sub.