| 摘要 |
PROBLEM TO BE SOLVED: To provide a rubber composition for the outer layers of tires, which has excellent ozone resistance in a wide environmental temperature range and can well control discoloration, and to provide a pneumatic tire using the same.SOLUTION: A rubber composition for the outer layers of tires comprises natural rubber, polybutadiene, carbon black, paraffin waxes, sulfur and a sulfenamide-based vulcanization promoter, wherein: the content of the polybutadiene is 30-70 mass% in terms of 100 mass% of the rubber component; the content of ≤25C normal paraffin waxes is 10.0-16.0 mass% and the content of 26-32C normal alkanes is 30.5-38.5 mass%, in terms of the paraffin wax 100 mass%; and the content of the carbon black is 40-60 pts.mass, the content of the sulfur is ≤1.5 pts.mass, and the content of the sulfenamide-based vulcanization promoter is≤0.75 pt.mass, in terms of 100 mass% of the rubber component. |
