Patent ID: 7262254
Filing Date: 2007-08-28
Classification: B60C,C08C,C08K,C08L

Abstract:
1. A tire having a tread of a rubber which is comprised of, based upon parts by weight per 100 parts by weight rubber (phr): (A) about 30 to about 80 phr of a siloxane functionalized styrene/butadiene copolymer elastomer composite (SBR composite) comprised of a styrene/butadiene copolymer elastomer (SBR-1) and a siloxane functional styrene/butadiene copolymer elastomer (SBR-2) which contains at least silicon atom within said elastomer with associated pendent alkoxy groups, and optionally hydroxyl groups, from said silicon atom, as a part of the (SBR-2) elastomer chain to thereby divide said elastomer into at least two segments thereof (SBR-2A and SBR-2B) with the silicon atom containing said siloxy group, and optionally said hydroxyl group, therebetween, wherein said SBR composite is thereby comprised of a polymodal molecular weight configuration comprised about 35 to about 55 weight percent thereof of said (SBR-1) having a number average molecular weight (Mn) in a range of about 200,000 to about 300,000 and, correspondingly, about 65 to about 35 weight percent thereof of said (SBR-2) having a number average molecular weight (Mn) in a range of about 400,000 to 550,000; wherein said elastomer contains from zero to a maximum of ten weight percent of at least one additional styrene/butadiene copolymer elastomer (SBR-3) pendent to said silicon atom and having an number average molecular weight (Mn) of greater than 550,000, (B) about 20 to about 70 phr of at least one additional conjugated diene based elastomer selected from the group consisting of polymers of the group consisting one of isoprene or 1,3-butadiene and copolymers of styrene with at least one of isoprene and 1,3-butadiene; (C) about 10 to about 120 phr of reinforcing filler for said tread rubber composition wherein said reinforcing filler is comprised of: