| 摘要 |
PROBLEM TO BE SOLVED: To provide a rubber composition for tire side section reinforcement that can improve high mileage and flat runnability in favorable balance; and a run flat tire.SOLUTION: A rubber composition for tire side section reinforcement includes: a rubber constituent; silica; and a silane coupling agent having a mercapto group. In the rubber composition, in 100 mass% of the rubber constituent, a content of a conjugated diene polymer that has a constitutional unit based on a conjugated diene and a constitutional unit shown by the following formula(I) and in which at least one terminal of the polymer is modified by a specific compound is at least 5 mass%, the total content of natural rubber and isoprene rubber is 15-80 mass%, a content of butadiene rubber containing a syndiotactic crystal is 15-80 mass%, a content of the silica is 5-150 parts by mass based on 100 parts by mass of the rubber constituent, a content of the silane coupling agent is 0.5-20 parts by mass of based on 100 parts by mass of the silica. The formula (I): -CH-CH(SiXXX)-. |
