Abstract: A rubber composition comprising 2.5 to 7.5 parts by weight of an ethylene/?-olefin copolymer having a melting point of 100° C. or higher and a glass transition temperature Tg of ?55° C. or lower, based on 100 parts by weight of ethylene/butene/diene copolymer rubber. The rubber composition can improve processability, such as roll processability and bite of the compound into the screw and maintain excellent compression set characteristics under the operating environment of fuel cells, while maintaining the characteristics of ethylene/butene/diene copolymer rubber, such as compression set characteristics (95° C., 500 hours) and low temperature elastic recovery test (evaluated by the TR10 value and TR70 value).

Abstract: A rubber composition comprising a nitroxide compound crosslinking agent containing 2.3 to 5.0 parts by weight of organic peroxide having a one-hour half-life temperature of 110 to 130° C., based on 100 parts by weight of an ethylene-butene-non-conjugated diene copolymer. Then, the ethylene-butene-non-conjugated diene copolymer can be used by being blended with EPDM in an amount of 50 wt % or less in the total amount of the ethylene-butene-non-conjugated diene copolymer and EPDM. A sealing material for fuel cell separators comprising a crosslinked molded article of the rubber composition, having functions required as a sealing material for separators, and having improved low temperature sealing properties and scorch resistance as well as excellent injection molding properties.

Abstract: A rubber composition comprising 1 to 10 parts by weight of an organic peroxide crosslinking agent having a one-hour half-life temperature of 110 to 130° C., based on 100 parts by weight of an ethylene-butene-non-conjugated diene copolymer. The ethylene-butene-non-conjugated diene copolymer can be used by being blended with EPDM in an amount of 50 wt % or less in the total amount of the ethylene-butene-non-conjugated diene copolymer and EPDM. A sealing material for fuel cell separators comprising a crosslinked molded article of the rubber composition has, in addition to functions required as a sealing material for separators, improved low temperature sealing properties.

Abstract: It is an object of the present invention to provide a rubber composition having: excellent sealing properties, heat resistance and acid resistance; a low reaction force, low hardness and low compression set; and excellent low-temperature recovery properties that contribute to sealing properties particularly in low-temperature environment. It is another object of the invention to provide uses of the rubber composition and main bodies on which the rubber composition has been mounted. The rubber composition of the present invention comprises a specific ethylene/?-olefin/non-conjugated polyene copolymer [A], a SiH group-containing compound [B] having two SiH groups in one molecule, and a SiH group-containing compound [C] having three SiH groups in one molecule.

Abstract: Provided is a rubber composition capable of providing a molding having: excellent sealing properties, heat resistance, and acid resistance; a low reaction force and low hardness; a reduced compression set; and especially an improved compression set and unsusceptibility to compression cracking at high temperatures. Also provided are a use of the rubber composition and a main body comprising the rubber composition mounted thereon. The rubber composition contains a specific ethylene/?-olefin/non-conjugated polyene copolymer [A], carbon black [B], and surface-modified silica [C] that is obtained by subjecting precipitated silica to surface modification and has a BET specific surface area of 30 to 80 m2/g, a particle diameter of 1.0 to 4.0 ?m as measured by the Coulter counter method, and an M value of 50 or more.

Abstract: It is an object of the present invention to provide a rubber composition having: excellent sealing properties, heat resistance and acid resistance; a low reaction force, low hardness and low compression set; and excellent low-temperature recovery properties that contribute to sealing properties particularly in low-temperature environment. It is another object of the invention to provide uses of the rubber composition and main bodies on which the rubber composition has been mounted. The rubber composition of the present invention comprises a specific ethylene/?-olefin/non-conjugated polyene copolymer [A], a SiH group-containing compound [B] having two SiH groups in one molecule, and a SiH group-containing compound [C] having three SiH groups in one molecule.

Abstract: It is an object of the present invention to provide a rubber composition which has been improved in mechanical properties with maintaining excellent various properties and is favorably used for a fuel cell sealing member, a hard disc drive top cover gasket member and an electric wire connector sealing member. It is another object of the present invention to provide main bodies mounted with the above respective members obtained by the use of the rubber composition. The rubber composition of the invention comprises a specific ethylene/?-olefin/non-conjugated polyene copolymer in which the non-conjugated polyene is a norbornene-based compound, a specific SiH group-containing compound, and if necessary, an organopolysiloxane. Such a rubber composition of the invention is excellent in mechanical properties and can be particularly favorably used for a fuel cell sealing member, a hard disc drive top cover gasket, an electric wire connector sealing member, etc.

Abstract: It is an object of the present invention to provide a rubber composition which has been improved in mechanical properties with maintaining excellent various properties and is favorably used for a fuel cell sealing member, a hard disc drive top cover gasket member and an electric wire connector sealing member. It is another object of the present invention to provide main bodies mounted with the above respective members obtained by the use of the rubber composition. The rubber composition of the invention comprises a specific ethylene/?-olefin/non-conjugated polyene copolymer in which the non-conjugated polyene is a norbornene-based compound, a specific SiH group-containing compound, and if necessary, an organopolysiloxane. Such a rubber composition of the invention is excellent in mechanical properties and can be particularly favorably used for a fuel cell sealing member, a hard disc drive top cover gasket, an electric wire connector sealing member, etc.

Abstract: A seal molding material for cell electrolytic solution, which comprises an EPDM composition comprising a peroxide-crosslinkable EPDM and an organic peroxide, the seal molding material being for use at the electrode site of a nickel-hydrogen cell, wherein the EPDM composition comprises preferably 100 parts by weight of a peroxide-crosslinkable EPDM, 10 to 150 parts by weight of a filler and 1 to 8 parts by weight of an organic peroxide, and not more than 40 parts by weight of hydrocarbon-based oil can be further contained. The seal material molded from the seal molding material for cell electrolytic solution has a sufficient durability against a potassium hydroxide-based electrolytic solution and a longer life, and is free from any deterioration, when energized at the electrode site of a nickel-hydrogen cell.

Abstract: A seal molding material for cell electrolytic solution, which comprises an EPDM composition comprising a peroxide-crosslinkable EPDM and an organic peroxide, the seal molding material being for use at the electrode site of a nickel-hydrogen cell, wherein the EPDM composition comprises preferably 100 parts by weight of a peroxide-crosslinkable EPDM, 10 to 150 parts by weight of a filler and 1 to 8 parts by weight of an organic peroxide, and not more than 40 parts by weight of hydrocarbon-based oil can be further contained. The seal material molded from the seal molding material for cell electrolytic solution has a sufficient durability against a potassium hydroxide-based electrolytic solution and a longer life, and is free from any deterioration, when energized at the electrode site of a nickel-hydrogen cell.

Abstract: A seal molding material for cell electrolytic solution, which comprises an EPDM composition comprising a peroxide-crosslinkable EPDM and an organic peroxide, the seal molding material being for use at the electrode site of a nickel-hydrogen cell, wherein the EPDM composition comprises preferably 100 parts by weight of a peroxide-crosslinkable EPDM, 10 to 150 parts by weight of a filler and 1 to 8 parts by weight of an organic peroxide, and not more than 40 parts by weight of hydrocarbon-based oil can be further contained. The seal material molded from the seal molding material for cell electrolytic solution has a sufficient durability against a potassium hydroxide-based electrolytic solution and a longer life, and is free from any deterioration, when energized at the electrode site of a nickel-hydrogen cell.

Abstract: A peroxide-vulcanizable fluorine-containing elastomer containing iodines as cross-linking sites, capable of producing vulcanization products having a distinguished heat resistance is produced by polymerization reaction of a fluorinated olefin having 2 to 8 carbon atoms in the presence of a diiodide compound represented by the following general formula:I--R--where R is a divalent fluorohydrocarbon group, chlorofluorohydrocarbon group or hydrocarbon group, having 2 to 8 carbon atoms, respectively, and 2,2-difluoroiodoethylene.