Patent ID: 7220798

Claim:
A process for making a hydrogenated block copolymer, comprising the steps of: a. reacting a living lithium-terminated polymer having the formula P-Li where P is a copolymer chain of one or more conjugated dienes having from 4 to 12 carbon atoms and one or more mono alkenyl arenes having from 8 to 18 carbon atoms with an alkoxy silane coupling agent having the formula R x —Si—(OR′) y , where x is 0 or 1, x+y=4, R and R′ are the same or different, R is selected from aryl hydrocarbon radicals, linear alkyl hydrocarbon radicals and branched alkyl hydrocarbon radicals, and R′ is selected from linear and branched alkyl hydrocarbon radicals, and where the molar ratio of Si to Li is from about 0.35 to about 0.7, thereby forming a coupled polymer; b. hydrogenating the coupled polymer under hydrogenation conditions to substantially saturate at least the olefinically derived double bonds of said coupled polymer without substantial degradation of the coupled polymer; and c. recovering the resulting hydrogenated polymer; wherein the resulting hydrogenated block copolymer comprises a mixture of from 0 to 5 weight percent tetra-branched block copolymer, from 0 to 60 weight percent tri-branched block copolymer, from 40 to 95 weight percent di-branched block copolymer and from 2 to 10 weight percent linear diblock copolymer.