Linear block copolymers, process for their preparation and adhesive compositions containing them.

摘要

Block copolymers of the structure A-B-C-D of improved processability derived from a vinyl aromatic monomer and a conjugated diene, having a total bound vinyl aromatic content in the range of from 10 to 40 wt%, wherein the conjugated diene has been polymerized in a 1,2 or 3,4 addition in an amount of from 1 to 20% of the total bound conjugated diene, and wherein A represents a predominantly poly(vinylaromatic)block, B represents a predominantly poly(conjugated diene), C represents a tapered block of the conjugated diene occurring in the block B and a vinyl aromatic monomer constituting the block D, which represents a predominantly poly(vinylaromatic)block wherein the tapering in block C shows an increasing content of vinyl aromatic monomer in the direction to block D, wherein the weight ratio of the conjugated diene occurring in block B and the conjugated diene occurring in block C is in the range of from 5:5 to 9:1, and the total apparent molecular weight of which is in the range of from 130.000 to 300.000; process for their preparation and adhesive compositions comprising them.