Abstract: A rubber composition for a torsional damper, comprising 10 to 200 parts by weight of carbon black having an iodine adsorption of 100 to 600 mg/g, a DBP oil absorption of 138 to 330 cm3/100 g and a nitrogen adsorption specific surface area of 100 to 530 m2/g, and 5 to 100 parts by weight of a liquid polyolefin oligomer having a number average molecular weight Mn of 3,000 to 4,000, based on 100 parts by weight of at least one of ethylene-propylene-non-conjugated diene terpolymer rubber, ethylene-butene-non-conjugated diene terpolymer rubber and ethylene-propylene copolymer rubber, wherein in the total amount of ethylene and propylene or butene, the content of propylene or butene is 35 to 55 wt. %.

Abstract: A rubber composition for a torsional damper has (A) a minimum value of tan ? at ?30° C. to 120° C. of 0.140 or more, (B) a ratio of tan ? at ?30° C. to tan ? at 60° C. of 3.5 or less, and (C) a ratio of E? at ?30° C. to E? at 60° C. of 21 or less.

Abstract: A rubber composition for a torsional damper has (A) a minimum value of tan ? at ?30° C. to 120° C. of 0.140 or more, (B) a ratio of tan ? at ?30° C. to tan ? at 60° C. of 3.5 or less, and (C) a ratio of E? at ?30° C. to E? at 60° C. of 21 or less.

Abstract: A rubber composition is provided which is excellent in crosslinking characteristics and processability and is excellent in durability and heat resistance after crosslinking by using a sulfur-based crosslinking agent and a peroxide crosslinking agent in combination. The rubber composition includes 100 parts by mass of ethylene-propylene non-conjugated polyene copolymer, 1 to 3 parts by mass of peroxide crosslinking agent, and 0.1 to 0.6 parts by mass of thiazole-based crosslinking promoter. A content ratio of propylene is 30 to 55 percent by the total content of ethylene and propylene in the EPDM polymer.

Abstract: A rubber composition for a torsional damper has (A) a minimum value of tan ? at ?30° C. to 120° C. of 0.140 or more, (B) a ratio of tan ? at ?30° C. to tan ? at 60° C. of 3.5 or less, and (C) a ratio of E? at ?30° C. to E? at 60° C. of 21 or less.

Abstract: An acrylic rubber composition comprising 5 to 80 parts by weight, preferably 10 to 60 parts by weight, more preferably 20 to 40 parts by weight, of a styrene-based resin, based on 100 parts by weight of acrylic rubber. A vibration insulation member having an excellent tan ? value at a high temperature and improved vibration insulation properties can be molded by adding a specific ratio of a styrene-based resin to acrylic rubber. This acrylic rubber composition can be effectively used as a molding material for a mount, a grommet, or the like in the vicinity of an automobile engine used in a high temperature environment.

Abstract: Provided are a halogenated butyl rubber composition which can be made low in hardness, being excellent in damping property and having excellent balance of the physical properties among kneading, roll-processing and crosslinking, and a vibration-insulating grommet using the halogenated butyl rubber composition. The halogenated butyl rubber composition contains 100 parts mass of halogenated butyl rubber and 3 to 20 parts mass of liquid unsaturated polybutadiene, and preferably further contains 0.1 to 5 parts mass of fatty acid amide. The halogenated butyl rubber composition is suitable for producing a vibration-insulating grommet.

Abstract: An acrylic rubber composition comprising 5 to 80 parts by weight, preferably 10 to 60 parts by weight, more preferably 20 to 40 parts by weight, of a styrene acrylic-based resin containing a functional group other than a carboxyl group, based on 100 parts by weight of acrylic rubber. A vibration insulation member having an excellent tan ? value at a high temperature and improved vibration insulation properties can be molded by adding a specific ratio of a styrene acrylic-based resin to acrylic rubber. This acrylic rubber composition can be effectively used as a molding material for a mount, a grommet, or the like in the vicinity of an automobile engine used in a high temperature environment.

Abstract: An object of the present invention is to provide an SBR composition for a torsional damper in which the SBR composition has a good physical property balance of high load-bearing properties, low CS properties, and the kneadability and roll processability of a rubber material, and to provide a torsional damper. The object is achieved in such a manner that the SBR composition for the torsional damper comprises at least: (a) an SBR polymer having a combined styrene content of 10 wt % to 50 wt %; (b) carbon black comprising FEF grade carbon black and HAF grade carbon black blended at a ratio of FEF:HAF=1:3 to 3:1; (c) a crosslinking system including sulfur, a sulfur-donating compound, and an organic peroxide compound; and (d) a co-crosslinking agent, wherein 60 parts by weight to 100 parts by weight of the carbon black as total parts by weight of the FEF grade carbon black and the HAF grade carbon black is blended based on 100 parts by weight of the SBR polymer, 0.4 part by weight to 2.

Abstract: Provided are a halogenated butyl rubber composition which can be made low in hardness, being excellent in damping property and having excellent balance of the physical properties among kneading, roll-processing and crosslinking, and a vibration-insulating grommet using the halogenated butyl rubber composition. The halogenated butyl rubber composition contains 100 parts mass of halogenated butyl rubber and 3 to 20 parts mass of liquid unsaturated polybutadiene, and preferably further contains 0.1 to 5 parts mass of fatty acid amide. The halogenated butyl rubber composition is suitable for producing a vibration-insulating grommet.

Abstract: An acrylic rubber composition comprising 5 to 80 parts by weight, preferably 10 to 60 parts by weight, more preferably 20 to 40 parts by weight, of a styrene acrylic-based resin containing a functional group other than a carboxyl group, based on 100 parts by weight of acrylic rubber. A vibration insulation member having an excellent tan ? value at a high temperature and improved vibration insulation properties can be molded by adding a specific ratio of a styrene acrylic-based resin to acrylic rubber. This acrylic rubber composition can be effectively used as a molding material for a mount, a grommet, or the like in the vicinity of an automobile engine used in a high temperature environment.

Abstract: An acrylic rubber composition comprising 5 to 80 parts by weight, preferably 10 to 60 parts by weight, more preferably 20 to 40 parts by weight, of a styrene-based resin, based on 100 parts by weight of acrylic rubber. A vibration insulation member having an excellent tan ? value at a high temperature and improved vibration insulation properties can be molded by adding a specific ratio of a styrene-based resin to acrylic rubber. This acrylic rubber composition can be effectively used as a molding material for a mount, a grommet, or the like in the vicinity of an automobile engine used in a high temperature environment.

Abstract: An object of the present invention is to provide an SBR composition for a torsional damper in which the SBR composition has a good physical property balance of high load-bearing properties, low CS properties, and the kneadability and roll processability of a rubber material, and to provide a torsional damper. The object is achieved in such a manner that the SBR composition for the torsional damper comprises at least:(a) an SBR polymer having a combined styrene content of 10 wt % to 50 wt %; (b) carbon black comprising FEF grade carbon black and HAF grade carbon black blended at a ratio of FEF:HAF=1:3 to 3:1; (c) a crosslinking system including sulfur, a sulfur-donating compound, and an organic peroxide compound; and (d) a co-crosslinking agent, wherein 60 parts by weight to 100 parts by weight of the carbon black as total parts by weight of the FEF grade carbon black and the HAF grade carbon black is blended based on 100 parts by weight of the SBR polymer, 0.4 part by weight to 2.

Abstract: An EPDM composition for a torsional damper. The EPDM composition is made of (a) an EPDM polymer, (b) liquid polyolefin oligomer, and (c) carbon black, the EPDM composition containing 100 parts by weight of EPDM polymer that is the EPDM polymer of (a) having a propylene content of 35 to 50 wt % in the total amount of ethylene and propylene, 5 to 30 parts by weight of liquid polyolefin oligomer that is the liquid polyolefin oligomer of (b) having a number average molecular weight Mn within a range of 3,000 to 4,000, and 10 to 120 parts by weight of carbon black that is the carbon black of (c) having a nitrogen adsorption specific surface area within a range of 100 to 150 m2/g, an iodine adsorption within a range of 110 to 160 mg/g, and a DBP oil absorption within a range of 70 to 135 cm3/100 g.

Abstract: An EPDM composition for a torsional damper. The EPDM composition is made of (a) an EPDM polymer, (b) liquid polyolefin oligomer, and (c) carbon black, the EPDM composition containing 100 parts by weight of EPDM polymer that is the EPDM polymer of (a) having a propylene content of 35 to 50 wt % in the total amount of ethylene and propylene, 5 to 30 parts by weight of liquid polyolefin oligomer that is the liquid polyolefin oligomer of (b) having a number average molecular weight Mn within a range of 3,000 to 4,000, and 10 to 120 parts by weight of carbon black that is the carbon black of (c) having a nitrogen adsorption specific surface area within a range of 100 to 150 m2/g, an iodine adsorption within a range of 110 to 160 mg/g, and a DBP oil absorption within a range of 70 to 135 cm3/100 g.