Patent ID: 7589152

Claim:
A block copolymer composition comprising: a. a tetra-branched block copolymer (IV) represented by the general formula (A-B) 4 X; b. a tri-branched block copolymer (III) represented by the general formula (A-B) 3 X; c. a di-branched block copolymer (II) represented by the general formula (A-B) 2 X; and d. a linear diblock copolymer (I) represented by the general formula A-B; where: i. A represents a polymer block of a mono alkenyl arene; ii. B represents a polymer block of a mixture of isoprene and 1,3-butadiene having a random distribution in a weight ratio of isoprene to butadiene from 70:30 to 40:60; iii. X represents the residue of a multi-functional coupling agent selected from silicon halides, siloxanes, epoxy alkoxysilanes, esters of monohydric alcohols with carboxylic acids, epoxidized oils, epoxides and divinylaromatics; iv. the weight percent of A blocks is from 14% to 22%; v. the relative amounts of copolymers IV, III, II, and I are from 0 to 20 weight percent IV, from 50 to 80 weight percent III, from 0 to 20 weight percent II and from 20 to 50 weight percent I, where the total of I, II, III and IV equals 100 weight percent; and vi. the melt flow rate of the polymer composition is at least 2.0 g/10 minutes at 200° C./5 kg as measured by ASTM D1238 (D condition).