Patent ID: 7608669

Claim:
A composition for producing impact-resistant thermoplastic materials consisting of a block copolymer that comprises as monomers an alkadiene and a vinyl aromatic monomer, wherein the block copolymer being selected from the group consisting of linear, radial, perfect and partially randomized blocks having the formula (I): [(B—(B/S) i —S) j ] k -Z (I), wherein i, j and k are an integer equal to or greater than 1; Z is a residue of a coupling or a termination agent; S is the vinyl aromatic monomer; and B is the alkadiene, which may optionally be totally or partially hydrogenated; wherein the block copolymer has a B/S ratio from 70/30 to 60/40; and at least one block of the vinyl aromatic monomer in the block copolymer is polydispersed having a polydispersity from 1.01 to 4.