| 摘要 |
PROBLEM TO BE SOLVED: To provide a rubber composition for a base tread in which rolling resistance performance, breaking strength, and processability can be improved in a good balance, and a pneumatic tire using the same.SOLUTION: The rubber composition for a base tread includes: a rubber component and silica, wherein the content of a conjugated diene polymer that has a structural unit based on a conjugated diene and a structural unit shown by formula (I) is at least 5 mass% based on 100 mass% of the rubber component, the conjugated diene polymer comprising such that at least a part of the polymer is modified by a specific compound, and the content of the silica is 5-150 pts.mass based on 100 pts.mass of the rubber component. In the formula (I), X, Xand Xeach independently denote a group shown by formula (Ia), a hydroxyl group, a hydrocarbyl group or a substituted hydrocarbyl group, and at least one of X, Xand Xdenotes a group shown by formula (Ia) or a hydroxyl group. In the formula (Ia), Rand Reach independently denote a 1-6C hydrocarbyl group, a 1-6C substituted hydrocarbyl group, a silyl group or a substituted silyl group, and Rand Rmay bond to form a ring structure with a nitrogen atom. |
