Patent ID: 8415447

Claim:
Polyolefin coated steel pipe having high dynamic fracture toughness of the coating of the steel pipe during installation handling and in service, comprising a steel pipe core and a polyolefin coating, the polyolefin coating comprising β-nucleated propylene block copolymers of from 90.0 to 99.9 wt % of propylene and 0.1 to 10.0 wt % of α-olefins of 2 or 4 to 18 carbon atoms and having an IRτ of the propylene homopolymer block of ≧0.98 and melt indices of 0.1 to 8 g/10 min at 230° C/2.16 kg, a test polyolefin pipe fabricated from the β-nucleated propylene copolymer having a critical pressure of >25 bars and a dynamic fracture toughness of >3.5 MNm −3/2 .