Tire rubber composition
A tire rubber composition that improves dry grip performance to or beyond conventional levels, while retaining grip performance sustainability and wear resistance during high-speed running is provided. A tire rubber composition comprising 40 to 180 parts by weight of carbon black having a nitrogen adsorption specific surface area of 80 to 400 m 2 /g and 1 to 100 parts by weight of aromatic copolymer blended in 100 parts by weight of diene rubber, the aromatic copolymer being a copolymer of an α-methylstyrene derivative represented by general formula (I) and indene.
1. A tire rubber composition comprising from greater than 70 parts by weight to 180 parts by weight or less of carbon black having a nitrogen adsorption specific surface area of from greater than 150 m 2 /g to 400 m 2 /g or less and 1 to 100 parts by weight of aromatic copolymer blended in 100 parts by weight of diene rubber, the aromatic copolymer being a copolymer of an α-methylstyrene derivative represented by general formula (I) and indene:
wherein R is an alkyl group having from 1 to 3 carbons.
2. The tire rubber composition according to claim 1 , wherein a softening point of the aromatic copolymer is 100 to 150° C.
3. A pneumatic tire comprising the tire rubber composition described in claim 1 .
4. A pneumatic tire comprising the tire rubber composition described in claim 2 .
5. The tire rubber composition according to claim 1 , wherein a content of styrene included in the styrene-butadiene rubber is from 25 to 50 weight %.
6. The tire rubber composition according to claim 1 , wherein a vinyl content in the styrene-butadiene rubber is from 10 to 75 weight %.
7. The tire rubber composition according to claim 1 , wherein a glass transition temperature (Tg) of the styrene-butadiene rubber is from −45 to −5° C.
8. The tire rubber composition according to claim 1 , wherein a weight average molecular weight of the styrene-butadiene rubber is from 500,000 to 2,000,000.
9. The tire rubber composition according to claim 1 , comprising from not less than 90 parts by weight to not greater than 140 parts by weight of the carbon black.
10. The tire rubber composition according to claim 1 , wherein the carbon black has a nitrogen adsorption specific surface area of from not less than 250 m 2 /g to not greater than 390 m 2 /g.