Patent ID: 6162873
Filing Date: 2000-12-19
Classification: C08F

Abstract:
An aromatic vinyl-conjugated diene block copolymer composed of a bound aromatic vinyl unit and a bound conjugated diene unit and containing at least a block aromatic vinyl segment and a conjugated diene homopolymer block, wherein the block copolymer is obtained by polymerizing conjugated diene monomer in a hydrocarbon solvent using an active organometallic compound as an initiator and then polymerizing a mixture of conjugated diene monomer and aromatic vinyl monomer, and further wherein:(1) a content of the bound aromatic vinyl unit in the block copolymer is 3 to 60 wt. %;(2) a proportion of block aromatic vinyl segment portions having a molecular weight at most a third of a molecular weight (A-Mp) corresponding to a peak in a molecular weight distribution curve of the block aromatic vinyl segment (A) as determined by gel permeation chromatography (GPC) is 55 to 90 mol % based on the total content of the block aromatic vinyl segment (A);(3) a molecular weight (Mp) corresponding to a peak in a molecular weight distribution curve of the block copolymer as determined by GPC is 10,000 to 1,000,000; and(4) a proportion of the block aromatic vinyl segment (A) is 50 to 95 wt. % based on the total content of the bound aromatic vinyl unit.