| 摘要 |
PROBLEM TO BE SOLVED: To obtain a composition for a sponge rubber having both excellent dimensional stability and foamability, and further to provide a vulcanized foamed and molded product. SOLUTION: This rubber composition for a sponge comprises (A) 100 pts.wt. copolymer rubber component comprising ethylene, a 3-20Cα-olefin and a nonconjugated polyene, and characterized by (a) molar ratio [ethylene/α-olefin] of the ethylene to the 3-20Cα-olefin regulated so as to be (40/60)-(90/10), (b) 1-50 content of the nonconjugated polyene expressed in terms of iodine value, and (c) 0.7-5 dl/g intrinsic viscosity [η] measured at 135 deg.C in decalin, and (B) 3-40 pts.wt. crystalline or amorphous synthetic resin, and is featured in the decrease of 5-40 points of Mooney viscosity at 100 deg.C after heat treatment compared to the one before the heat treatment when the heat treatment is carried out in 200 deg.C atmosphere for 10 min.
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