Patent ID: 7728074
Filing Date: 2010-06-01
Classification: C08F,C08L

Abstract:
1. A block copolymer composition comprising (i) a diblock copolymer comprising one block of a monovinylaromatic hydrocarbon and one block of a conjugated diene having a peak molecular weight from 30,000 to 78,000 and a vinyl content from 35 to 80 mol percent based on the number of repeat monomer units in the conjugated diene block, and (ii) a block copolymer comprising at least two blocks of monovinylaromatic hydrocarbon and at least one block of conjugated diene, the block copolymer selected from the group consisting of linear triblock copolymers having a peak molecular weight that is 1.5 to 3.0 times the peak molecular weight of the diblock copolymer, multiarm coupled block copolymers having a peak molecular weight that is 1.5 to 9.0 times the peak molecular weight of the diblock copolymer, and mixtures thereof, wherein each block copolymer has a vinyl content from 35 to 80 mol percent based on the number of repeat monomer units in the conjugated diene block, wherein the melt index for the block copolymer composition is from about 20 g/10 min to about 35 g/10 min as determined by ASTM D-1238, condition G (200° C., 5 kg) and wherein the ratio of (i) to (ii) in the block copolymer composition is greater than 1:1.