Abstract: An iodine-containing compound consisting of at least two repeating units selected from the formulae:--(CH.sub.2 CF.sub.2 CF.sub.2 O).sub.a ----(CHClCF.sub.2 CF.sub.2 O).sub.b ----(CCl.sub.2 CF.sub.2 CF.sub.2 O).sub.c ----(CHFCF.sub.2 CF.sub.2 O).sub.d ----(CFClCF.sub.2 CF.sub.2 O).sub.e ----(CF.sub.2 CF.sub.2 CF.sub.2 O).sub.f --wherein a, b, c, d, e and f are each 0 or a positive integer and satisfy the following equations:2.ltoreq.a+b+c+d+e+f.ltoreq.200 and1.ltoreq.a+c+d+fand an iodine atom at at least one end of a molecule, which can provide a block copolymer which is useful as a grease.

Abstract: A denture base at least a part of which comprises a thermoplastic fluoroelastomer exhibits excellent characteristics as a denture base and particularly as a relining material for a denture base.

Abstract: A polymeric dielectric material comprising a terpolymer which comprises 30 to 90% by mole of VdF, 5 to 70% by mole of TrFE and 0.1 to 20% by mole of HFP, having large permittivity, which is improved by heat treatment.

Abstract: A fluorine-containing polymer substantially comprising (A) at least one fluorine-containing olefin of the formula:CF.sub.2 =CXYwherein X is a hydrogen atom or a fluorine atom and Y is a hydrogen atom, a chlorine atom, a fluorine atom, a trifluoromethyl group, a difluoromethyl group, a C.sub.1 -C.sub.3 perfluoroalkoxy group or a group of the formula:--(CF.sub.2).sub.m COOMwherein m is an integer of 0 to 3 and M is a hydrogen atom, a C.sub.1 -C.sub.4 alkyl group, a sodium atom or a potassium atom but when X is a hydrogen atom, Y is always a hydrogen atom, (B) one or more C.sub.4 -C.sub.8 fluorine-containing dienes, (C) at least one iodine atom and (D) at least one saturated or unsaturated fluoro or chlorofluorohydrocarbon group, the molar ratio of the diene (B) and the olefin (A) being from 1.times.10.sup.-4 to 5.times.10.sup.-2, the iodine atom(s) (C) being from 0.001 to 10% by weight based on the weight of the polymer and the molar ratio of the group (D) and the olefin (A) being from 1.times.10.sup.-5 to 5.

Abstract: An easily cross linkable fluorine-containing polymer comprising: (1) a polymeric chain comprising one or more polymer segments, at least one polymer segment of which consists of units of at least one fluorine-containing ethylenically unsaturated compound having 2 to 8 carbon atoms, or units of said fluorine-containing ethylenically unsaturated compound and at least one other monomer selected from the group consisting a fluorine-free ethylenically unsaturated compound having 2 to 4 carbon atoms and a fluorine-containing diene having 4 to 8 carbon atoms, (2) at least one bromine atom liberated from a brominated compound of the formula: RBr.sub.x (wherein R is a saturated hydrocarbon residue and x is a number corresponding to the bonding valency of the residue R) in an amount of 0.

Abstract: A fluorine-containing elastomeric copolymer which comprises units of at least one fluorovinyl ether of the formula: ##STR1## wherein X is C.sub.1 -C.sub.3 perfluoroalkyl, C.sub.1 -C.sub.3 .omega.-hydroperfluoroalkyl or C.sub.1 -C.sub.3 .omega.-chloroperfluoroalkyl, Y is hydrogen, chlorine, fluorine, trifluoromethyl, difluoromethyl or chlorodifluoromethyl and n is an integer of 1 to 4 and units of at least one other fluorine-containing monomer copolymerizable therewith, the content of the fluorovinyl ether units being 15 to 50 mol %, which has excellent resistance to low temperatures.

Abstract: A polyfluoroallyl ether of the formula: ##STR1## wherein each X, which is the same or different, is a chlorine atom or a fluorine atom and each Y, which is the same or different, is a hydrogen atom, a chlorine atom or a fluorine atom, which is useful as a modifier for polymers.

Abstract: A process for producing a readily crosslinkable liquid, fluorine-containing polymer having a narrow range of molecular weight distribution and containing iodine in the molecule in an amount of 1 to 30% by weight based on the weight of the polymer, which comprises polymerizing vinylidene fluoride and at least one other fluoroolefin in the presence of a radical-producing source and an iodinated compound of the formula: Rf/I.sub.x wherein Rf is a saturated perfluorocarbon group, a saturated perfluorochlorocarbon group or a saturated fluorochlorohydrocarbon group and x is an integer of not less than 1 corresponding to the bonding valency of Rf while maintaining the proportion of the mole number of the monomeric components (M) to the mole number of the iodinated compound (I) in a range between 10 and 1,200.

Abstract: A co-crosslinkable blend composition which comprises (1) an iodine-containing fluoroelastomer, (2) at least one of silicone oligomers, silicone elastomers, fluorosilicone elastomers, phosphonitrilic fluoroelastomers, tetrafluoroethylene/propylene copolymers and hexafluoropropylene/ethylene copolymers and (3) an organic peroxide.

Abstract: An easily cross linkable fluorine-containing polymer substantially comprising: (1) a polymeric chain comprising one or more polymer segments, of which at least one polymer segment consisting of units of vinylidene fluoride alone or of units of vinylidene fluoride and one or more of other fluoroolefins, and (2) at least one iodine atom liberated from an iodinated compound of the formula: RI.sub.x (wherein R is a saturated or unsaturated fluorohydrocarbon or chlorofluorohydrocarbon residue having 1 to 8 carbon atoms and x is an integer of 1 or 2 corresponding to the bonding valency of the residue R) in an amount of 0.

Abstract: A polymeric dielectric having an outstanding dielectric constant, which essentially consists of a copolymer of vinylidene fluoride and triflouroethylene in a molar ratio of from about 95:5 to 10:90, preferably of from about 85:15 to 20:80, more preferably of from about 75:25 to 35:65.

Abstract: A segmented polymer comprising a sequence of two or more polymer segments, an iodine atom liberated from an iodinated compound bonded at a terminal position of said sequence and a fragment of the iodinated compound from which at least one iodine atom has been removed bonded at another terminal position of said sequence, whereby said sequence intervenes between said iodine atom and said fragment, wherein adjacent polymer segments are different in steric configuration or monomeric composition, at least one of said polymer segments containing fluorine and each polymer segment having a molecular weight of not less than 10,000 but at least one polymer segment having a molecular weight of not less than 30,000. The polymer may contain additional moieties which originate from the monomers which constitute the polymer segments and from the iodinated compound, when the latter has a polymerizable double bond. The segmented polymers are prepared in a sequence of steps involving radical polymerization.

Abstract: A process for production of modified polychlorotrifluoroethylene having a low crystallinity with a good processability, which comprises polymerizing, as a monomeric component, chlorotrifluoroethylene or its mixture with at least one of other polymerizable monomers in an amount of not more than about 50 mol% based on the monomeric component in the presence of a fluorine-containing elastomeric polymer, preferably in the coexistence of water and 1,1,2-trichloro-1,2,2-trifluoroethane.

Abstract: Ion exchanger comprising a water-insoluble copolymer prepared by post-polymerizing at least one fluoroolefin monomer to a perfluorovinylacetic acid-vinylidene fluoride copolymer containing not less than 25% by mole of the perfluorovinylacetic acid unit in an aqueous solution of said copolymer in the presence of an organic or inorganic peroxide. The ion exchanger has excellent heat and chemical resistances and dimensional stability.