PURPOSE: To obtain a racing tire which is improved in the durability aganst high-speed heating, by specifying the structure of styrene butadiene, the I2 absorption amount of carbon black, the rubber compositions and the post-vulcanization characteristics, in a cap tread rubber.
CONSTITUTION: A cap tread rubber having a complex elastic modulus at 100°C after vulcanization of 2W50MPa and a loss elastic modulus of 0.2 to 0.6 is formed by blending more than 70pts.wt. of styrene butadiene copolymer rubber in which a bound styrene is of 30W50wt%, the content of 1, 2 vinyle coupling in the butadiene part is in a range of 10W50wt%, the Mooney viscosity ML1+4 at 100°C is more than 60, the glass transient temperature is in a range of -45W -10°C, and more than 35pts.wt. thereof have more than one atomic groups of perdetermined structure formulae coupled to molecular chains by carbon-carbon coupling, with 90W300pts.wt. of carbon black having an I2 absorption amount of 100W200mg/g. With this arrangement the durability of the tire is enhanced to obtain a racing tire.
HIRAKAWA HIROSHI
KAWAKAMI KINYA
TOKIEDA AKINORI
| JP42024174A | ||||
| JPS58189203A | 1983-11-04 |
| US3109871A | 1963-11-05 |
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