Rubber composition and tire

摘要

The present invention has its object to provide a rubber composition excellent in low-exothermic property, breaking strength, and crack growth resistance, and a pneumatic tire including at least one of a base tread, a cushion, a carcass and a tie gum that are prepared using the rubber composition. The present invention relates to a rubber composition including: a rubber component which contains
(a) 10 to 30% by mass of at least one of a butadiene rubber modified by a compound represented by the formula (1):;
and a tin-modified polybutadiene rubber resulting from polymerization with a lithium initiator
(b) 10 to 40% by mass of a modified styrene-butadiene rubber having a bound-styrene content of 21% by mass or less; and(c) 20 to 80% by mass of a diene rubber other than (a) and (b), and(d) 7 to 50 parts by mass of silica per 100 parts by mass of the rubber component.

主权项

1. A pneumatic tire comprising:
at least one of a base tread, a cushion, and a tie gum that are prepared using a rubber composition comprising: a rubber component which contains (a) 10 to 30% by mass in 100% by mass of the rubber component of at least one of a butadiene rubber modified by a compound represented by the formula (1): wherein R1, R2 and R3 are the same or different and independently represent an alkyl group, an alkoxy group, a silyloxy group, an acetal group, a carboxyl group, a mercapto group, or a derivative thereof; R4 and R5 are the same or different and independently represent a hydrogen atom or an alkyl group; and n represents an integer, and a tin-modified polybutadiene rubber resulting from polymerization with a lithium initiator and having a tin atom content of 50 to 3000 ppm, a vinyl-bond content of 5 to 50% by mass, and a molecular weight distribution (Mw/Mn) of 2 or less; (b) 10 to 40% by mass of a modified styrene-butadiene rubber having a bound-styrene content of 21% by mass or less; and (c) 20 to 80% by mass of a diene rubber other than (a) and (b); (d) 7 to 50 parts by mass of silica per 100 parts by mass of the rubber component; and (e) 5 to 50 parts by mass of carbon black per 100 parts by mass of the rubber component, said carbon black having a nitrogen adsorption specific surface area of 20 to 50 m2/g.