Polyolefin multilayer pipe

摘要

Polyolefin multilayer pipes consisting at least one of the layers of a β-nucleated propylene homopolymer and/or β-nucleated copolymers from 90.0 to 99.9% by weight of propylene and 0.1 to 10.0% by weight of α-olefins. The pipes are to be classified in ring stiffness class ≧4. The pipes are suitable for non pressure pipe applications, preferably for outdoor use, for above as well as underground drainage and sewerage pipe systems, surface water pipes, pipes for cable protection, pipes for cold climate conditions and for indoor use, soil and waste water pipes.

主权项

1. A multilayer pipe comprised of a plurality of layers, at least one of the layers being comprised of:
a β-nucleated propylene polymer that is: a propylene homopolymer having melt index of 0.05 to 10 g/10 min at 230° C. at a load of 2.16 kg that is β-nucleated, a propylene block copolymer of 90.0 to 99.9% by weight propylene and 0.1 to 10.0% by weight of one or more α-olefins having 2 or 4 to 18 carbon atoms and a melt index of 0.05 to 15 g/10 min at 230° C. at a load of 2.16 kg that is β-nucleated, or a mixture of both; wherein the normalized impact energy ED of the multilayer pipe is at least 600 Nm/m, and further wherein the β-nucleated propylene homopolymer has an IRτ≧0.98, a tensile modulus of ≧1500 MPa at +23° C. and a notched Charpy impact strength at −20° C., of ≧3 kJ/m2 and the β-nucleated propylene block copolymer has an IRτ≧0.98, a tensile modulus of ≧1100 MPa at +23° C. and a notched Charpy impact strength ≧6 kJ/m2 at −20° C.