Abstract: In a rod sealing system, which comprises a buffer ring, a rod seal, and a dust seal, provided successively in this order from a fluid hydraulic side toward the outside in an annular clearance between two members in reciprocating motion, the buffer ring is made up of a thermoplastic polyurethane molding product obtained by subjecting a thermoplastic polyurethane molding product prepared by reaction of (A) a high molecular weight polycarbonatediol having a number average molecular weight Mn of 500-6,000, (B) an aromatic diisocyanate, and (C) a low molecular weight diol as a chain elongation agent in an NCO/OH ratio of 0.95-1.20, to heat treatment under conditions that a glass transition point (Tg) of hard phases becomes 170° C. or higher, preferably 170-230° C., and an endothermic peak area (?H) at Tg becomes 5 J/g or more, by differential scanning calorimetry.

Abstract: In a rod sealing system, which comprises a buffer ring, a rod seal, and a dust seal, provided successively in this order from a fluid hydraulic side toward the outside in an annular clearance between two members in reciprocating motion, the buffer ring is made up of a thermoplastic polyurethane molding product obtained by subjecting a thermoplastic polyurethane molding product prepared by reaction of (A) a high molecular weight polycarbonatediol having a number average molecular weight Mn of 500-6,000, (B) an aromatic diisocyanate, and (C) a low molecular weight diol as a chain elongation agent in an NCO/OH ratio of 0.95-1.20, to heat treatment under conditions that a glass transition point (Tg) of hard phases becomes 170° C. or higher, preferably 170-230° C., and an endothermic peak area (?H) at Tg becomes 5 J/g or more, by differential scanning calorimetry.

Abstract: A modified acrylic rubber having distinguished molding characteristics and O-ring compression set characteristic is produced by mixing an acrylic rubber having reactive functional groups such as active chlorine groups, carboxylic groups, epoxy groups, active ester groups, etc. with an unsaturated compound reactive with the reactive functional group with heating in the absence of a solvent.

Abstract: An acrylic elastomer obtained by copolymerization of about 60 to about 99.9% by weight of at least one of alkyl acrylate and alkoxyalkyl acrylate; about 10 to about 0.1% by weight of a halogen-containing vinyl compound having a secondary or tertiary halogenoalkyl group; and about 30 to 0% by weight of a monomer copolymerizable with the acrylate and the vinyl compound, sum total being 100% by weight, is an acrylic elastomer containing the halogen-containing vinyl compound as a cross-linking site monomer capable of forming an active halogen group cross-linkable with an organic peroxide or the like, and has a high vulcanization torque.

Abstract: A copolymer comprising an alkyl acrylate and an unsaturated ester compound represented by the following general formula:CH.sub.2 .dbd.CRCOO(CH.sub.2)nPhOR', (1)CH.sub.2 .dbd.CRCOO(CH.sub.2)nOCO(CH.sub.2)mPhOR', (2)CH.sub.2 .dbd.CHOCO(CH.sub.2)nOCO(CH.sub.2)mPhOR', (3)CH.sub.2 .dbd.CHO(CH.sub.2)nOCO(CH.sub.2)mPhOR' or (4)CH.sub.2 .dbd.CHPh(CH.sub.2)nOCO(CH.sub.2)mPhOR' (5)where R is a hydrogen atom or a methyl group; R' is a hydrogen atom, an acyl group or a trialkylsilyl group; and Ph is a phenylene group, forms a blend rubber having a good heat resistance and a good amine resistance with a fluorine-containing elastomer.

Abstract: A novel acrylic copolymer elastomer comprising ?I! an alkyl acrylate; ?II! (a) CH.sub.a .dbd.CRCOOR.sub.2 OCOR.sub.1, (b) CH.sub.2 .dbd.CRCO?O(CH.sub.2) pCO!qOR.sub.1 or (c) CH.sub.2 .dbd.CRCOOR.sub.2 ?CO(CH.sub.2)pO!qCOR.sub.1 ; and ?III! (1) CH.sub.2 .dbd.CRCOO(CH.sub.2)nPhOR', (2) CH.sub.2 .dbd.CRCOO(CH.sub.2)nOCO(CH.sub.2)mPhOR', (3) CH.sub.2 .dbd.CHOCO(CH.sub.2)mPhOR', (4) CH.sub.2 .dbd.CHOCO(CH.sub.2)nOCO(CH.sub.2)mPhOR', (5) CH.sub.2 .dbd.CHO(CH.sub.2)nOCO(CH.sub.2)mPhOR' or (6) CH.sub.2 .dbd.CHPh(CH.sub.2)nOCO(CH.sub.2)mPhOR' where R is a hydrogen atom or a methyl group, R.sub.1 is an alkyl group, R.sub.2 is an alkylene group, R' is a hydrogen atom, an acyl group or a trialkylsilyl group and Ph is a phenylene group, provides a blend rubber having an improved cold resistance and an intermediate heat resistance between the heat resistance of acrylic copolymer elastomer and that of fluorine-containing elastomer, when blended with the fluorine-containing elastomer.

Abstract: A rubber compound comprising a fluorine rubber component and an acrylic rubber component is produced by adding an acrylic monomer to an aqueous emulsion of fluorine-containing elastomer obtained by emulsion polymerization, using a fluorine-containing surfactant, followed by radical polymerization reaction. The obtained rubber compound can satify both of vulcanization moldability and heat aging resistance, and is at a lower cost than the expensive fluorine rubber.

Abstract: A copolymer comprising an alkyl acrylate and an. unsaturated ester compound represented by the following general formula:(1) CH.sub.2 .dbd.CRCOO(CH.sub.2)nPhOR',(2) CH.sub.2 .dbd.CRCOO(CH.sub.2)nOCO(CH.sub.2)mPhOR',(3) CH.sub.2 .dbd.CHOCO(CH.sub.2)nOCO(CH.sub.2)mPhOR',(4) CH.sub.2 .dbd.CHO(CH.sub.2)nOCO(CH.sub.2)mPhOR' or(5) CH.sub.2 .dbd.CHPh(CH.sub.2)nOCO(CH.sub.2)mPhOR'where R is a hydrogen atom or a methyl group; R' is a hydrogen atom, an acyl group or a trialkylsilyl group; and Ph is a phenylene group, forms a blend rubber having a good heat resistance and a good amine resistance with a fluorine-containing elastomer.