| 摘要 |
PROBLEM TO BE SOLVED: To provide a high-hardness vulcanized rubber composition which can be produced with a good processibility, has a sufficient hardness in spite of its low sulfur content, is excellent in physical properties such as tensile strength and elongation, has a low temperature dependence of stiffness even when the contents of a reinforcement and a softener are high, and exhibits a low compression set and excellent sealing properties. SOLUTION: This high-hardness vulcanized rubber composition contains (a) a high-mol.-wt. ethylene/α-olefin/diene copolymer rubber and (b) a copolymer rubber selected from among (b1) low-mol.-wt. ethylene/α-olefin/diene copolymer rubbers and (b2) modifications thereof in a wt. ratio of (b)/(a) of (3/100)-(40/100), is prepared by vulcanizing a rubber composition containing sulfur as a vulcanizing agent, and comprises (A) a vulcanized ethylene/α-olefin/diene rubber phase having a JIS A hardness of 65-85 and (B) high-crosslink-density vulcanized ethylene/α-olefin/diene rubber particles dispersed therein, both formed by the vulcanization. The JIS A hardness of this vulcanized rubber composition is higher than that of the vulcanized rubber phase (A) by at least 3.
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