| 摘要 |
PROBLEM TO BE SOLVED: To provide a rubber composition for a rim cushion suppressing the reduction in the elongation at break after traveling, while maintaining hardness, and a pneumatic tire using it. SOLUTION: The rubber composition for rim cushion comprises (A) (i) at least 30 pts.wt. of a low and constant viscosity natural rubber in a solid state which has been prepared by drying a natural rubber latex, in which 0.001 wt.% or more of a constant viscosity agent is contained relative to the weight of a solid natural rubber and a magnesium content is reduced to 0.02 wt.% or less relative to the weight of the solid natural rubber by the addition of a water-soluble ammonium salt, by the atomization drying method using a pulse wave, and (ii) 100 pts.wt. of a rubber capable of being sulfur-vulcanized containing 20-50 pts.wt. of polybutadiene rubber, and (B) 50-90 pts.wt. of carbon black having an iodine adsorption amount (IA) of 50-120 mg/g and a DBP absorption amount of 60-140 ml/100 g. The pneumatic tire using it for the rim cushion is also provided. COPYRIGHT: (C)2009,JPO&INPIT
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