| 摘要 |
PROBLEM TO BE SOLVED: To provide a rubber composition for tire rim cushion or gum finishing that can combine low heat build-up, hardness, abrasion resistance, and setting resistance by a high level.SOLUTION: A composition comprises blending: 55-75 pts.mass of carbon black (1) in which a nitrogen adsorption specific surface area is at least 35 m/g and less than 50 m/g; and 5-20 pts.mass of carbon black (2) in which a nitrogen adsorption specific surface area is at least 50 m/g and at most 95 m/g based on 100 pts.mass of a rubber constituent including: 30-70 mass% of a butadiene rubber in which a cis-1,4 bond content is at least 97%, a Mooney viscosity (ML1+4) at 100°C is at least 45, and a ratio of a (T-cp)/(ML1+4) of 5 mass% toluene solution viscosity at 25°C(T-cp)(cps) to the Mooney viscosity is at least 2.0; and 30-70 mass% of other diene rubbers, wherein the sum of the carbon blacks (1) and (2) is 60-95 pts.mass. |
