Branched block copolymers and their manufacture

Abstract From the Canadian patent

Branched block copolymers of from 60 to 95% by weight of a monovinyl-aromatic compound and from 40 to 5% by weight of a conjugated diene, of which the olefinic double bonds are selectively hydrogenated. The copolymers have a structure of the general formula (A-13)n-X, where A is a polymer segment exhibiting, polymodal distribution, based on the monovinyl-aromatic compound B, is a hydrogenated polymer segment based on the conjugated diene having a crystallinity of less then 5% X is the radical Or an at, least trifunctional coupling agent and n is an integer not less than 3. The copolymers may be used for the manufacture of highly transparent shaped articles, especially packaging materials.