Rubber composition for tires and pneumatic tire

Abstract

Provided are a rubber composition for tires that shows a balanced improvement in properties such as fuel economy, processability, heat aging resistance, abrasion resistance, wet-grip performance, performance on snow and ice, and handling stability, and a pneumatic tire formed from the rubber composition. The present invention relates to a rubber composition for tires, containing: a highly purified, modified natural rubber having a pH adjusted to 2-7; carbon black and/or a white filler; and a silane coupling agent represented by the following Formula (S1): wherein Rrepresents a monovalent group selected from —Cl, —Br, —OR, —O(O═)CR, —ON═CRR, —ON═CRR, —NRR, and —(OSiRR)(OSiRRR), wherein R, R, and Rare the same as or different from one another and each represent a hydrogen atom or a C1-C18 monovalent hydrocarbon group, and h represents a number whose average value is 1 to 4; Rrepresents R, a hydrogen atom, or a C1-C18 monovalent hydrocarbon group; Rrepresents R, R, a hydrogen atom, or the group: —[O(RO)]— wherein Rrepresents a C1-C18 alkylene group, and j represents an integer of 1 to 4; Rrepresents a C1-C18 divalent hydrocarbon group; Rrepresents a C1-C18 monovalent hydrocarbon group; and x, y, and Z are numbers satisfying the following relationships: x+y+2z=3, 0≦x≦3, 0≦y≦2, and 0≦z≦1.