ORGANOPOLYSILOXANE, COMPOUNDING AGENT FOR RUBBER, RUBBER COMPOSITION CONTAINING THE AGENT AND TIRE

摘要

PROBLEM TO BE SOLVED: To provide an organopolysiloxane having improved dispersibility of silica, effective for improving various physical properties of a rubber composition and suitable for a rubber composition for tire tread. SOLUTION: The objective organopolysiloxane has a number-average molecular weight of 600-300,000 and contains a structural unit expressed by general formula R1-SiZ13 (R1 is a 1-18C substituted or non-substituted hydrocarbon group; Z1 is a group selected from OX group and siloxane residue; and at least one of the Z1 group is siloxane residue) and a structural unit expressed by general formula Z2p(CH3)(3-p)Si-R2-Sm-R2-Si-(CH3)(3-p)Z2p (R2 is a 1-10C bivalent hydrocarbon group; Z2 is a group selected from OX group and siloxane residue; at least one of the Z2 groups is siloxane residue; X is hydrogen atom or a univalent hydrocarbon group; (p) is 2 or 3; (m) is 1-10; and at least one of Z1 and Z2 is an alkoxy group) in the molecule.