Abstract: The present invention relates to an annular seal material comprising a core and an outer layer covering a periphery of the core, wherein the outer layer has a thick film portion and a non-thick film portion in a cross section in a circumferential direction. According to the present invention, provided are an annular seal material that is constituted of a core and an outer layer and that suppresses cracking in the outer layer and protrusion of the core from the outer layer, and a method for manufacturing the same.

Abstract: The present invention relates to a method for manufacturing an annular seal material comprising a core and an outer layer covering a periphery of the core, comprising: a preforming step of providing one or two or more rope-like preforms comprising an uncrosslinked core made of a crosslinkable rubber composition for a core, and an uncrosslinked outer layer, made of a crosslinkable rubber composition for an outer layer, covering a periphery of the uncrosslinked core; a first hot pressing step of placing the rope-like preform in a first mold to hot press mold a portion other than end portions of the rope-like preform; and a second hot pressing step of contacting two end portions of the rope-like preform with each other and placing the same in a second mold to carry out hot press molding, in presented order.

Abstract: Provided are an elastomer composition including a first fluoroelastomer that is a copolymer of tetrafluoroethylene and perfluoro (alkoxyvinyl ether) and a second fluoroelastomer different from the first fluoroelastomer, and a sealing material including a crosslinked product of the elastomer composition.

Abstract: Provided are a perfluoroelastomer composition which contains 100 parts by weight of a perfluoroelastomer containing a constituent unit derived from a nitrile group-containing monomer, and 0.01 to 5 parts by weight of ketjen black; and a sealing material including a crosslinked product of the perfluoroelastomer composition.

Abstract: Provided are an elastomer composition including a first fluoroelastomer that is a copolymer of tetrafluoroethylene and perfluoro (alkoxyvinyl ether) and a second fluoroelastomer different from the first fluoroelastomer, and a sealing material including a crosslinked product of the elastomer composition.

Abstract: Provided are a perfluoroelastomer composition which contains 100 parts by weight of a perfluoroelastomer containing a constituent unit derived from a nitrile group-containing monomer, and 0.01 to 5 parts by weight of ketjen black; and a sealing material including a crosslinked product of the perfluoroelastomer composition.