| 摘要 |
PROBLEM TO BE SOLVED: To obtain a rubber composition excellent in heat resistance by including an acrylic rubber with a carbon black having an Lc, the average pile height in the direction of C axis of a layer plane within a crystallite, of a specified or higher value. SOLUTION: This composition comprises 100 pts.wt. acrylic rubber, 10-100 pts.wt. carbon black wherein the Lc, the pile height in the direction of C axis of a layer plane within a crystallite is at least 2μm, and optionally, 3-8 pts.wt. age resistor, a vulcanizing agent, a filler, a plasticizer, etc. The acrylic rubber is obtained by copolymerizing 100-40 wt.% acrylic ester monomer such as methyl acrylate with 0-10 wt.% crosslinking site monomer such as 2-chloroethyl vinyl ether, O-70 wt.% ethylene monomer, and 0-55 wt.% vinyl acetate monomer. The carbon black used is exemplified by acetylene black or furnace black and is desirably acetylene black having a mean particle diameter of at most 60 nm and a DBP absorption of 100-350 ml/100 g.
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