Polyolefin multilayer pipe
AssigneeBorealis Technology Oy
InventorsCarl-Gustaf Ek, Hans Sandberg, Siegfried Liedauer, James McGoldrick
Life of this patent
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Abstract
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.
Claims21
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.
A process for producing a multilayer pipe, comprising extruding a multilayer pipe in which at least one the layer is extruded from a melt comprising β-nucleated propylene polymer which is a β-nucleated propylene homopolymer having melt index of 0.05 to 10 g/10 min at 230° C./2.16 kg, β-nucleated propylene copolymer of 90.0 to 99.9 wt % propylene and 0.1 to 10.0 wt % α-olefins of 2 or 4 to 18 carbon atoms and having melt index of 0.1 to 15 g/10 min at 230° C./2.16 kg, or a mixture of both, the β-nucleated propylene polymer having an Irτ≧0.98, wherein the β-nucleated propylene polymer comprises the at least one layer.
A process for producing a multilayer pipe, comprising injection molding at least one layer of the multilayer pipe from a melt comprising β-nucleated propylene polymers which is a β-nucleated propylene homopolymer having melt index of 0.05 to 10 g/10 min at 230° C./2.16 kg, a β-nucleated propylene copolymer of 90.0 to 99.9 wt % propylene and 0.1 to 10.0 wt % α-olefins of 2 or 4 to 18 carbon atoms and having melt indexes of 0.1 to 15 g/10 min at 230° C./2.16 kg, or a mixture of both, the β-nucleated propylene polymer has an IRτ≧0.98, wherein the β-nucleated propylene polymer comprises the at least one layer.
Dependencies are inferred from the claim text.