materials feature | Wood-plastic composites
Wacker’s Genioplast silicone
additives raise the manufac- turing efficien- cy of WPCs
while boosting product quality
the researchers. Numerical codes can help to overcome this, by cutting the amount of trial and error that is normally required. These types of simulation tool can help the designer to improve die channel geometry – through using either numerical-based trial and error procedures, or automatic algorithms that search for an optimised geometry. The flow balance for the WPC die was optimised, and computation times were reduced from around 7.5 hours to 1.25 hours. As the full optimisation took five runs, the total time was cut from 38.5 hours to 5.5 hours. Results showed that, even with
simple parallelisation, computation times could be reduced significantly for both types of die. “It is important to note that these results were
obtained without any complex memory management on the GPU, and therefore there is room for additional future improvements,” said the researchers.
Launched at K2016 At K2016, Imerys showcased an additive that boosts the performance of recycled polyolefins. ImerPlast is a compatibilised, mixed polymer compound, consisting of recycled PE and PP resin, with a mineral-based compatibilising agent. It extends the number of useful applications of recycled plastic feedstock, allowing a higher recycling rate and increasing the scope of recycled polymers, says the company. The engineered mineral – which also overcomes phase separation and ensures stable production – is already being used in pipes for drains and sewers and for wood plastic composite (WPC) decking. Also at the show, Struktol exhibited its RP 17
additive – a combination of lubricant and odour neutralising mask. It was originally designed for reducing or eliminating compounding and end-product odours in WPCs, and has now been modified for use in other recycling applications. Wacker launched a range of thermoplastic silicone
additives that raise the manufacturing efficiency of WPCs. Its Genioplast WPC additives improve processing when extruding plastic blends that contain wood, to make manufacturing more cost effective and less energy intensive. The additives also enhance the mechanical properties and water-repellency of the materials, says the company. To enable the separate components to bond
effectively – and to keep resistance in the process as low as possible – the additives are incorporated as lubricants. They contain a thermoplastic silicone
16 PIPE & PROFILE EXTRUSION | November/December 2016
elastomer. In comparison with conventional silicones – which cure irreversibly following vulcanization – ther- moplastic silicones behave thermoplastically within a certain temperature range. “A regular silicone wouldn’t melt under these
conditions – but ours does,” said Martin Schmid, senior marketing manager at Wacker Silicones. He says the company has developed the additives in
masterbatch form. Tests show that 1% of the additive can increase throughput by 15-25% – depending on the plastic blend and extruder used. This leads to lower unit costs in production. In comparison, says Wacker, conventional lubricants require WPC manufacturers to use 2-6% of additive to achieve the same effect during extrusion. Genioplast WPC additives can be blended easily as the thermoplastic silicone elastomer is already premixed with the corresponding plastic. At present, formulations with PP (PP 20A08) and PE (HDPE 20A03) are available, but the company is also working on a PVC version. Wacker says that the additives lead to end products with higher impact strength and flexural toughness, as well as reduced water absorption.
Click on the links for more information: ❙
www.trex.com ❙
www.dpdsi.com ❙
www.mtib.gov.my ❙
www.amiplastics.com ❙
www.wki.fraunhofer.de/en ❙
www.hifiventproject.eu ❙
www.starrett.com ❙
www.uef.fi ❙
www.uminho.pt ❙
www.imerys.com ❙
www.struktol.com ❙
www.wacker.com
www.pipeandprofile.com
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