Patent ID: 6410624
Filing Date: 2002-06-25
Classification: B60C,C08K,C08L,Y02T

Abstract:
A rubber composition comprised of, based upon 100 parts by weight rubber (phr), (A) about 25 to about 75 phr of styrene-rich segmented styrene/isoprene/butadiene terpolymer elastomer comprised of styrene/butadiene segments and polyisoprene segments and, correspondingly, about 25 to about 75 phr of at least one additional elastomer selected from at least one of cis 1,4-polyisoprene, styrene/butadiene copolymer, styrene/isoprene copolymer and 3,4-polyisoprene; wherein the content of the styrene/butadiene copolymer segments is in a range of about 15% to about 50% of the terpolymer and, correspondingly, the content of the polyisoprene segments is in a range of about 85% to about 50% of the terpolymer; wherein the styrene/butadiene segments are styrene-rich segments which contain about 20 to about 50 weight percent bound styrene; and wherein said segmented styrene/isoprene/butadiene terpolymer is characterized by having two Tg's, namely a first Tg of said styrene/butadiene segment in a range of about +10Â° C. to about âˆ’30Â° C. and a second Tg of said polyisoprene segments in a range of about âˆ’50Â° C. to about âˆ’70Â° C. and wherein said first and second Tg's are spaced apart by at least 20Â° C.