Coupled styrene-isoprene-butadiene rubber

摘要

The subject invention discloses a process for preparing a coupled styrene-isoprene-butadiene rubber which is particularly valuable for use in making automobile tire tread rubber compounds which comprises the steps of (1) solution terpolymerizing in an organic solvent from 5 weight percent to 40 weight percent styrene, from 1 weight percent to 10 weight percent isoprene, and from 50 weight percent to 94 weight percent 1,3-butadiene, based on total monomers, to a conversion of at least about 90% to produce a living styrene-isoprene-butadiene polymer, wherein the terpolymerization is initiated with an organolithium compound, and wherein the terpolymerization is conducted in the presence of a polar modifier at a molar ratio of the polar modifier to the organolithium compound, which is within the range of 0.5:1 to 5:1, and wherein the terpolymerization is conducted at a temperature which is within the range of 20°C to 150°C; and (2) coupling the living styrene-isoprene-butadiene polymer with a coupling agent selected from the group consisting of tin tetrachloride and silicon tetrachloride, wherein the molar ratio of the coupling agent to the organolithium compound is within the range of 1:3 to 1:6.