| 摘要 |
PROBLEM TO BE SOLVED: To provide a rubber composition having both cutting resistance and chipping resistance by making high hardness compatible with high elongation before and after aging. SOLUTION: The rubber composition is obtained by mixing not less than 5 pts.wt. of silica and carbon black having nitrogen absorption specific surface area of not less than 90 m<SP>2</SP>/g, the amount of the sum of the carbon black and the silica being 40 to 60 pts.wt., (a) pts.wt. of sulfur, (b) pts.wt. of a compounding agent B represented by the formula: R<SB>2</SB>N-(C=S)-S-S-(CH<SB>2</SB>)<SB>x</SB>-S-S-(C= S)-NR<SB>2</SB>(wherein R is C<SB>6</SB>H<SB>5</SB>CH<SB>2</SB>and x is 6) and one or more sulphenamide-based vulcanization accelerators, their sum amount being (c) pts.wt. with 100 pts.wt. of a rubber component comprising natural rubber and/or polyisoprene rubber wherein (a), (b) and (c) satisfy the following three relating formulas at the same time: b≥0.2, 1.0≤a+b/2≤1.5 and 0.4≤c/(a+b/2)≤0.8. COPYRIGHT: (C)2004,JPO
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