MATERIALS | POLYOLEFINS
Right:
Egeplast’s HexelOne SLM pipe has been used to extend a gas pipeline in Bavaria
applications such as domestic pipe,” said the patent document. Its aim with the material was to develop a resin with “improved hydrostatic strength at higher temperatures and high pressure, as well as excel- lent slow crack growth resistance and improved processability”. The company expects the resin to be used for both pipes and fittings, in applications including snow melt and heat recovery systems.
Blending advantage Borealis has developed a process for producing multi-modal PE blends – including ultra-high molecular weight compounds. The company says that producing these types of homogenous blends is usually difficult. However, it has discovered that this can be overcome by blending the UHMW PE component with a PE of lower molecular weight when the two elements are in at least partially liquid form. Such resins could be used in a range of applica-
tions, including injection moulded items, films and pipes.
In collaboration with sister company Borouge,
Borealis has also developed a PE pipe composition that it says overcomes sagging and improves extrusion properties. The formulation consists of a base resin – comprising a copolymer of ethylene and one other co-monomer – as well as carbon black (1-10wt%) and other additives. The patent also covers a process to make the
material and article – especially pressure pipes – from it. “There is a need for PE compositions – especially
for pressure pipe – which show an improved balance of low sagging behaviour and processability, so they are suitable for pipes with wall thicknesses of at least 100mm,” said the patent document.
High stability Last year, SABIC applied for a patent on a new ‘stabilised polyolefin’ composition. The material consists of “at least a homopolymer or copolymer of ethylene or propylene”, along with an anti-oxi- dant called cholestanyl ferulate. The resulting material is likely to have wide
application, in areas including food packaging, pharmaceutical products and pipes. Cholestanyl ferulate is a bio-based anti-oxidant
that SABIC says offers “improved radical scaveng- ing ability” compared to Vitamin E – which has also been used as an anti-oxidant in plastics. “There is a continuous need to provide im- proved stabilised polyolefin compositions having
20 PIPE & PROFILE EXTRUSION | March 2021
no dangerous effects when dispersed in the environment,” said the company in its application. Norwegian research organisation Norner has developed a process to make new multi-modal PE grades for pipes. In its patent application, it says polymerisation of
the material is done in two stages – both of which use a metallocene catalyst. “Currently, metallocene catalysts are exploited to a much lesser extent commercially for the production of PE for pipe production than Ziegler- Natta catalysts,” said the patent application. The application also covers a process for making pipes using the material, and the pipe itself.
CLICK ON THE LINKS FOR MORE INFORMATION: �
www.egeplast.de �
www.aquaspira.com �
www.birmingham.ac.uk �
www.gpsuk.com �
www.borealisgroup.com �
www.stwater.co.uk �
www.ukwir.org �
www.simona.de �
www.aquatherm.de �
www.unitedpolysystems.com �
www.uponor.com �
www.ads-pipe.com �
www.dow.com �
www.borealisgroup.com �
www.borouge.com �
www.sabic.com �
www.norner.no
www.pipeandprofile.com
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