Tire treads are required to have high-level properties, such as mainly high fuel economy and high abrasion resistance. Various techniques for improving these properties have been examined.
For example, fuel economy is known to be improved by introducing a functional group having an affinity for filler into the polymer chain end, while abrasion resistance is known to be improved by using a high molecular weight polymer having a molecular weight of 250,000 or more.
However, the introduction of a functional group having an affinity for filler and the use of a high molecular weight polymer unfortunately lead to an increase in the hardness of rubber compositions and deterioration of the processability.
Patent Literature 1 discloses a tire rubber composition having fuel economy and abrasion resistance that are improved by incorporation of a liquid resin having a softening point of −20° C. to 45° C. and a specific silica. However, there is still room for improvement in achieving a balanced improvement in these properties while providing good processability.