Patent ID: 6867258

Claim:
A high transparency composition consisting essentially of (1) from 30% to 95% of polystyrene homopolymer; (2) from 70% to 5% of a composition of one or more vinylarene-conjugated diene block copolymers; the percentage sum of (1) and (2) being equal to 100; wherein composition (2) consists essentially of (2a) from 30% to 60% by weight of one or more copolymers with a linear structure; (2b) from 70% to 40% by weight of one or more copolymers with a branched structure; wherein (i) the copolymers with a linear structure (2a) have structure of the type B-T-A; (ii) the copolymers with a branched structure (2b) have formula (I): wherein: 1) A is a polyvinylarene block; 2) b is a monomeric unit of conjugated diene; 3) T is a vinylarene conjugated diene random copolymer; 4) x is the number of monomer units which form a polydiene block B; 5) B is the polydiene block; 6) n and m are the number of branches of the copolymer, n+m is from 1 to 5; 7) B-T-A is the partially block copolymer grafted on the polydiene function -(-b-) x - or on the diene units of the random copolymer T, the weight average molecular weight of the above composition (2) is from 30,000 to 400,000, and the conjugated diene blocks are unsaturated, wherein a 2.0 mm thick sample of the high transparency composition has a transparency of 80-89%.