Pneumatic tire having improved abrasion resistance
AssigneeThe Yokohama Rubber Co., Ltd.
InventorsShingo Midorikawa, Kinya Kawakami, Yasushi Kikuchi, Motoji Fujita
Life of this patent
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Abstract
The cap tread portion composed of a rubber composition having a tan.delta. (0.degree. C.) of at least 0.45 and a tan.delta. (60.degree. C.) of at least 0.25 comprising (i) a p-phenylenediamine type antioxidant, 2,2,4-trimethyl-1,2-dihydroquinoline etc, and carbon black having a nitrogen specific surface area of at least 70 m.sup.2 /g and a 24M4DBP of at least 80 ml/100 g or (ii) a p-phenylenediamine based antioxidant, a 2,2,4-trimethyl-1,2-dihydroquinoline or other polymer mixture of a specific polymer content, and carbon black having a nitrogen specific surface area of at least 70 m.sup.2 /g and a 24M4DBP of at least 80 ml/100 g, blended with a rubber.
Claims1
A pneumatic tire having a cap tread portion composed of a rubber composition having a tan.delta. (0.degree. C.) of at least 0.45 and a tan.delta. (60.degree. C.) of at least 0.25, which composition comprises a blend of:
- (i) 1 to 10 parts by weight of a p-phenylenediamine antioxidant,
- (ii) 1 to 10 parts by weight of a mixture of the polymers of 2,2,4-trimethyl-1,2-dihydroquinoline where the dimer content is at least 20% by weight, the trimer content is at least 15% by weight, and the tetramer content is at least 5% by weight, wherein the total content of the di-to tetra-mers is at least 45% by weight;
- (iii) 30 to 100 parts by weight of carbon black having a nitrogen specific surface area of at least 70 m.sup.2 /g and a 24M4DBP of at least 80 ml/100 g;
- and
- 100parts by weight of a rubber, wherein at least 50% of the total rubber is styrene-butadiene copolymer rubber.
Dependencies are inferred from the claim text.