Thermoplastic comp contng an elastomeric block

摘要

Thermoplastic elastomeric comp. contng. (1) a block copolymer A-B-A where both A's are similar or dissimilar polymer blocks of a mono-alkenyl aromatic hydrocarbon and B is a polymer block of a conjugated diene hydrocarbon, each block A having a mol. wt. of 25,000-500,000, and (2) an aromatic asphaltic bitumen having a C:H ratio in the range 0.6-1.25 and a penetration index of at most zero, the bitumen forming 5-50% of the total wt. of (1) and (2). The bitumen improves the flow of the block polymer to a greater extent than do the known polymeric extenders, e.g. polystyrene, and it does not alter the hardness of the block copolymer. The bitumen is also compatible with extender oils.