Process for making a coupled low vinyl block copolymer composition and the resulting composition

Abstract

This invention relates to a process for making a coupled, low vinyl block copolymer composition, comprising the steps of: a) reacting a living lithium-terminated polymer having the formula P-Li, where P is a copolymer chain having at least one polymer block A composed of one or more mono alkenyl arenes having 8 to 18 carbon atoms and at least one polymer block B composed of one or more conjugated dienes having 4 to 12 carbon atoms, with an alkyltrialkoxysilane coupling agent having the formula R—Si—(OR′)3, where R is selected from branched alkyl radicals having from 3 to 12 carbon atoms, and R′ is a methyl group, and where the molar ratio of Si to Li is between 0.3 and 1.0, thereby forming a coupled block copolymer composition; and b) recovering the resulting coupled, low vinyl block copolymer composition. The invention also relates to the resulting coupled, low vinyl block copolymer compositions that are free from bromine-containing contaminants.

Dependencies are inferred from the claim text.