US Patent 7696281 Polyolefin blends and pipe

A polyolefin blend comprising:(a) from 30 to 80 weight % of a low molecular weight copolymer comprising from 85 to 100 weight % of ethylene and from 15 to 0 weight % of one or more C4-8 alpha olefins having a density from 0.953 to 0.965 g/cm3 and a melt flow rate (2.16 kg 190° C.) from 0.1 to 20.0 g/10 minutes; and(b) from 70 to 20 weight % of a high molecular weight copolymer comprising from 85 to 99.9 weight % of ethylene and from 15 to 0.1 weight % of one or more C4-8 alpha olefins having a density from 0.915 to 0.940 g/cm3 and a melt flow rate (21.6 kg 190° C.) from 0.05 to 5.0 g/10 minutes, said copolymer being prepared with a single site catalyst is useful in the preparation of pipe.