MODIFIED POLYSILOXANE, RUBBER COMPOSITION MADE BY USING IT, AND RUBBER COMPOSITION FOR TIRE TREAD

摘要

PROBLEM TO BE SOLVED: To give hardness with reduced temperature dependence, obtain excellent tanδbalance and improve the gripping force on the ice or snow and the wear resistance while making it possible to maintain low modulus by blending a tire tread rubber composition with polysiloxanes modified with a liquid polymer and having specified structures. SOLUTION: A rubber in an amount of 100 pts.wt. is compounded with a polysiloxane having siloxane structures of formula I and/or formula II (wherein R<1> is a 1-6C alkyl or a 1-21C acyl; a is 1 to 200; and t is 2 or 3) and formula III (wherein b is 1 to 200; and r is 1 to 100) and/or a polysiloxane having siloxane structures of formula I and/or formula II and formula IV (wherein R<2> is a 2-4C alkylene; R<3> is a monovalent hydrocarbon group; c is 1 to 200; and s is 1 to 100), in an amount of 1-50 pts.wt. A rubber selected from natural rubber, polybutadiene rubbers, styrene/butadiene copolymer rubbers, etc., in an amount of 100 pts.wt. may be compounded with a carbon black in an amount of 45-80 pts.wt. and the polysiloxanes in an amount of 5-50 pts.wt.