Patent ID: 6429245
Filing Date: 2002-08-06
Classification: B60C,C08K,C08L,Y10T

Abstract:
A pneumatic tire having a tread of a rubber composition characterized by being comprised of, based on 100 parts by weight rubber, a combination of a minor amount of elastomers having a high Tg in a range of about âˆ’30Â° C. to about +10Â° C. and a major amount of elastomers having a low Tg in a range of about âˆ’85Â° C. to about âˆ’110Â° C. and exclusive of elastomers having a Tg between âˆ’30Â° C. and âˆ’85Â° C.;(A) elastomers consisting of about 20 to 50 phr of at least one synthetic elastomer having a Tg in a range of âˆ’30Â° C. to about +10Â° C. selected from the group consisting of (1) isoprene/butadiene copolymer containing about 10 to about 90 percent units derived from isoprene; (2) 3,4-polyisoprene having a 3,4-microstructure content of at least 60 percent; and (3) emulsion polymerization prepared styrene/butadiene copolymer having from about 45 to about 65 percent units derived from styrene and a vinyl 1,2-content based on the butadiene component thereof in a range of about 8 to about 15 percent; and/or solution polymerization prepared styrene/butadiene copolymer having from about 15 to about 40 percent units derived from styrene and a vinyl 1,2-content based on the butadiene component thereof in a range of 15 to 60 percent; and (B) elastomers consisting of from at least 50 to about 80 phr of at least one synthetic elastomer having a Tg in a range of âˆ’85Â° C. to about âˆ’110Â° selected from the group consisting of (1) isoprene/butadiene copolymer having about 10 to about 30 percent units derived from isoprene; and (2) cis 1,4-polybutadiene rubber having about 90 to about 98 percent cis 1,4-microstructure, and a vinyl 1,2-content in a range of about 2 to about 10 percent with the remainder being primarily of a trans 1,4-microstructure; and (C) about 40 to about 100 phr of particulate reinforcing filler selected from (1) carbon black or (2) carbon black and silica with a weight ratio of carbon black to silica in a range of about 1/20 to about 20/1; and (D) at least one silica coupler for the silica, if silica is used, having a moiety reactive with the surface of said silica and another, sulfur based, moiety interactive with said elastomer.