Patent ID: 7276550

Claim:
A silica reinforced rubber composition which consists essentially of (1) a rubbery polymer, (2) an elongated silica, wherein the elongated silica has a width that is within the range of about 5 nm to about 40 nm and wherein the elongated silica has a length of about 40 nm to about 300 nm, (3) a silica coupling agent of the structural formula: Z-Alk-S n -Alk-Z, wherein Z is selected from the group consisting of wherein R is an alkyl group of 1 to 4 carbon atoms, a cyclohexyl group or a phenyl group; wherein R′ is an alkoxy group containing 1 to 8 carbon atoms or a cycloalkoxy group containing 5 to 8 carbon atoms; and wherein Alk is a divalent hydrocarbon of 1 to 18 carbon atoms, and wherein n represents an integer of 2 to 8 carbon atoms, and (4) optionally, at least one conventional rubber compounding ingredient selected from the group consisting of carbon black, sulfur, fillers, accelerants, oils, waxes, scorch inhibiting agents, and processing aids.