| 摘要 |
PROBLEM TO BE SOLVED: To obtain a tire tread rubber compsn. which is excellent in on-ice frictional force by compounding a raw rubber blend contg. a diene rubber with a specified amt. of polytetrafluoroethylene specified in average mol.wt. and average particle size and fluorinated even at the molecular ends. SOLUTION: 100 pts.wt. raw rubber blend comprising 50wt.% or higher diene rubber (e.g. a natural or a polybutadiene rubber) and other rubbers is compounded with 1-20 pts.wt. polytetrafluoroethylene having an average mol.wt. of 500-10,000 and an average particle size of 10μm or lower and fluorinated even at the molecular ends, 0.1-10 pts.wt. silane coupling agent e.g. bis-[3-(triethoxysilyl)-propyl] tetrasulfide}, and required amts. of a carbon black, a vulcanizing agent, a vulcanization accelerator, a vulcanizing aid, an antioxidant, etc., and kneaded to give a tire tread rubber compsn. The compsn. is thermally vulcanized to give a tire tread having a JIS hardness of 45-75, a difference in hardness between at 20 deg.C and at 0 deg.C of 5-15, a strength at break of 13MPa or higher, and an elongation at break of 450% or higher.
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