Abstract: To provide a novel crosslinking system of fluorine-containing elastomer giving a crosslinked product particularly having improved mechanical strength and compression set at high temperature. A fluorine-containing rubber composition comprising a fluorine-containing elastomer having carboxyl group and/or alkoxycarbonyl group at an end of a trunk chain and/or branched chain as a crosslinkable group.

Abstract: The present invention provides a graft or a block polymer in which a fluorine rubber and a silicone rubber are chemically bonded. The present invention is a graft or a block polymer comprising at least one kind of a silicone rubber segment and at least one kind of a fluorine elastomer segment. Furthermore, it is preferable that a fluorine containing elastomer segment is an elastomer segment comprising vinylidene fluoride or an elastomer segment comprising tetrafluoroethylene and that a silicone rubber segment has a unit of dimethylsiloxane and/or methyl-3,3,3-trifluoropropylsiloxane.

Abstract: The present invention provides a fluorine-containing elastomer composition excellent in heat resistance, comprising a fluorine-containing elastomer containing a vinylidene fluoride unit, which is capable of a crosslinking reaction, and a crosslinking agent. The present invention also provides a molded article, a sealing material, and a sealing material for an oxygen sensor excellent in heat resistance, which comprises the composition. The present invention is a fluorine-containing elastomer composition comprising (A) at least one compound selected form the group consisting of a compound containing at least two crosslinking reaction group s represented by the general formula (1), a compound represented by the general formula (2), a compound represented by the general formula (3) and a compound represented by the general formula (4); and (B) a fluorine-containing elastomer capable of a crosslinking reaction with the compound (A), comprising a vinylidene fluoride unit.

Abstract: This invention provides a novel compound which can be properly used as a surfactant, a method of producing a fluoropolymer, surfactant and a fluoropolymer aqueous dispersions using the novel compound. This invention is a fluoroalkylcarboxylic acid derivative which is represented by the general formula (i): Rf1(OCH2CF2CF2)n1OCX1X2CF2(Rf2)n2COOM??(i) wherein Rf1 represents a straight or branched fluoroalkyl group containing 1 to 20 carbon atoms, which fluoroalkyl group may optionally contain 1 to 5 oxygen atoms in the principal chain thereof, Rf2 represents a straight or branched fluoroalkylene group containing 1 to 25 carbon atoms, said fluoroalkylene group may optionally contain 1 to 5 oxygen atoms in the principal chain thereof, n1 represents an integer of 0 to 3, n2 represents an integer of 0 or 1, X1 and X2 are the same or different and each represents hydrogen atom or fluorine atom, and M represents NH4 or a monovalent metal element.

Abstract: The present invention provides a method of producing a fluoroelastomer excellent in dispersion stability at low cost, at a high rate of polymerization and in high yields. The present invention is a method of producing a fluoroelastomer comprising an emulsion polymerization of a fluorinated monomer in the presence of a water-soluble radical polymerization initiator, wherein the emulsion polymerization is carried out in the presence of a compound (1) containing a functional group reactive in radical polymerization and a hydrophilic group and a fluorinated compound (2) containing a fluorocarbon group comprising 1 to 6 continuously united carbon atom with fluorine atom directly bound to each of them as well as a hydrophilic group.

Abstract: This invention provides a novel compound which can be properly used as a surfactant, a method of producing a fluoropolymer, surfactant and a fluoropolymer aqueous dispersions using the novel compound. This invention is a fluoroalkylcarboxylic acid derivative which is represented by the general formula (i): Rf1(OCH2CF2CF2)n1OCX1X2CF2(Rf2)n2COOM??(i) wherein Rf1 represents a straight or branched fluoroalkyl group containing 1 to 20 carbon atoms, which fluoroalkyl group may optionally contain 1 to 5 oxygen atoms in the principal chain thereof, Rf2 represents a straight or branched fluoroalkylene group containing 1 to 25 carbon atoms, said fluoroalkylene group may optionally contain 1 to 5 oxygen atoms in the principal chain thereof, n1 represents an integer of 0 to 3, n2 represents an integer of 0 or 1, X1 and X2 are the same or different and each represents hydrogen atom or fluorine atom, and M represents NH4 or a monovalent metal element.

Abstract: The fluorine-containing polymer having a small number of ionic functional groups is prepared by a process, in which emulsion polymerization proceeds stably and produced polymer does not adhere to side walls of a polymerization reactor even without using an emulsifying agent, and the process comprises a first step for preparing a dispersion comprising fluorine-containing emulsified particles having ionic functional groups by polymerizing a fluorine-containing monomer mixture comprising a perhalo ethylenic monomer and a nonperhalo ethylenic monomer by using a water soluble radical polymerization initiator without adding an emulsifying agent, and a second step for preparing a fluorine-containing polymer having ionic functional groups in a small amount by emulsion polymerization of fluorine-containing monomers using a radical polymerization initiator in the presence of the fluorine-containing emulsified particles having ionic functional groups without adding an emulsifying agent, wherein the fluorine-containing e

Abstract: The invention provides a fluoropolymer composition capable of improving the characteristics of the cured material obtained therefrom. A fluoropolymer composition comprising a methylene group-containing fluoropolymer (A) and a hydrosilylation catalyst (B), wherein the methylene group-containing fluoropolymer (A) has methylene group-containing repeating units in the main chain thereof and is capable of hydrosilylation in the presence of the hydrosilylation catalyst (B) and one terminus of the chain is a carbon-carbon double bond or an Si—H group and the other terminus of the chain is an Si—H group or a carbon-carbon double bond.

Abstract: The present invention has for its object to provide a fluorocopolymer which is available at low cost, has fluidity at room temperature, and is curable, a method of producing the same copolymer and a curable composition having good processability and in situ moldability. The present invention is directed to a fluorocopolymer which is fluid at room temperature and curable, and which is obtainable from a trifluorovinyl group-containing monomer with an ethylenically unsaturated double bond moiety being a trifluorovinyl group.

Abstract: The invention provides a fluoropolymer composition capable of improving the characteristics of the cured material obtained therefrom. A fluoropolymer composition comprising a methylene group-containing fluoropolymer (A) and a hydrosilylation catalyst (B), wherein the methylene group-containing fluoropolymer (A) has methylene group-containing repeating units in the main chain thereof and is capable of hydrosilylation in the presence of the hydrosilylation catalyst (B) and one terminus of the chain is a carbon-carbon double bond or an Si—H group and the other terminus of the chain is an Si—H group or a carbon-carbon double bond.

Abstract: The present invention provides a novel fluorine-containing rubber composite material having both of excellent fuel impermeability and excellent cold resistance, a fuel impermeable sealing material comprising the composite material and a process for preparing the composite material. The fluorine-containing rubber composite material comprises crosslinked particles of fluorine-containing silicone rubber dispersed in a fluorine-containing rubber. It is preferable that the fluorine-containing rubber comprises a vinylidene fluoride/tetrafluoroethylene/perfluoro vinyl ether copolymer, and the composite material has cold resistance of not more than ?35° C. and fuel permeability of not more than 500 g·mm/m2·day. The fuel impermeable sealing material comprises the composite material. The process for preparing the composite material comprises a step for co-coagulation of a fluorine-containing rubber emulsion and an emulsion of crosslinked fluorine-containing silicone rubber.

Abstract: The present invention provides a method for producing a fluoroelastomer using an emulsifier which is inexpensive and hardly remains in product polymers. The present invention is related to a method for producing a fluoroelastomer, wherein vinylidene fluoride and at least one fluoroolefin monomer other than vinylidene fluoride are copolymerized in the manner of an emulsion polymerization in the presence of an emulsifier represented by C5F11COOM, wherein M represents H, NH4 or an alkali metal.

Abstract: The present invention provides a peroxide-vulcanizable fluorine-containing elastomer composition which is remarkably improved in fluidity and thereby exhibits improved processability, though conventional fluorine-containing elastomer compositions could be molded only by a molding process having a problem in its productivity, for instance, compression molding or transfer molding which has been used so far as a general molding process. The present invention further provides a molded article obtained by vulcanizing the composition. The present invention also provides a fluorine-containing elastomer composition in which a large amount of a filler can be blended.

Abstract: The present invention provides a process for preparing a fluorine-containing polymer having few branched chains and little weight change in high temperatures, which is a new process wherein composition distribution substantially does not occur. The fluorine-containing polymer is prepared by a batch copolymerization process conducted under conditions of reduced temperature of at least 0.95 and reduced pressure of at least 0.80 of the critical constant calculated from critical temperature, critical pressure and composition ratio of each monomer in the gaseous phase of the reaction vessel using the Peng-Robinson formula.

Abstract: The present invention provides a process for preparing a fluorine-containing elastomer in a high productivity comparable to that of non-iodine transfer polymerization process by carrying out an iodine transfer polymerization at high pressure. The present invention also provides a fluorine-containing elastomer prepared by this process, and fluorine-containing molded articles. The process is a batch copolymerization process conducted under conditions that the reduced temperature of the critical constant is at least 0.95 and the reduced pressure of the critical constant is at least 0.80 wherein the reduced temperature and the reduced pressure are calculated using the Peng-Robinson formula from the critical temperature, the critical pressure and the composition ratio of each of the monomers in the gaseous phase in a reaction vessel, in which ethylenically unsaturated compounds containing at least one fluoroolefine are copolymerized in the presence of a compound having the formula: Rf1.

Abstract: The present invention provides a crosslinkable composition comprising a fluorine-containing rubber, a crosslinking agent and an additive, a laminated article having a rubber layer formed by using the composition, and a hose.

Abstract: The present invention provides a fluorine-containing elastomer composition comprising a fluorine-containing elastomer (A) and a fluorine-containing elastomer (B) having a fluorine amount of at least 67% by weigh and a lower molecular weight than the fluorine-containing elastomer (A), wherein the fluorine amount of the fluorine-containing elastomer (B) is larger than a fluorine amount of the fluorine-containing elastomer (A). The present invention also provides a molded article obtained by crosslinking the fluorine-containing elastomer composition.

Abstract: The present invention provides a process for preparing a fluorine-containing polymer having few branched chains and little weight change in high temperatures, which is a new process wherein composition distribution substantially does not occur. The fluorine-containing polymer is prepared by a batch copolymerization process conducted under conditions of reduced temperature of at least 0.95 and reduced pressure of at least 0.80 of the critical constant calculated from critical temperature, critical pressure and composition ratio of each monomer in the gaseous phase of the reaction vessel using the Peng-Robinson formula.

Abstract: To provide a novel crosslinking system of fluorine-containing elastomer giving a crosslinked product particularly having improved mechanical strength and compression set at high temperature. A fluorine-containing rubber composition comprising a fluorine-containing elastomer having carboxyl group and/or alkoxycarbonyl group at an end of a trunk chain and/or branched chain as a crosslinkable group.

Abstract: The present invention provides a process for preparing a fluorine-containing elastomer in a high productivity comparable to that of non-iodine transfer polymerization process by carrying out an iodine transfer polymerization at high pressure. The present invention also provides a fluorine-containing elastomer prepared by this process, and fluorine-containing molded articles. The process is a batch copolymerization process conducted under conditions that the reduced temperature of the critical constant is at least 0.95 and the reduced pressure of the critical constant is at least 0.