| abstract |
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), D represents a predominantly poly(vinylaromatic)block, and C represents a tapered block of the conjugated diene occurring in the block B and a the vinyl aromatic occuring in the block D, 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 wherein the total apparent molecular weight of which is in the range of from 130,000 to 300,000. |