FOCUS WASTE AND RESOURCE RECOVERY
Research and industry discuss A A seminar has brought together research and industry to explain how they developed novel solutions for sensing and treating residual contaminants on HDPE milk bottles
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esearch and industry experts recently gathered at a Towards a Waste Free Future: Technology Readiness in Waste and Resource Recovery seminar in Sydney, co-hosted by the NSW Smart Sensing Network (NSSN) and Australian Academy of Technology and Engineering (ATSE). The seminar convened a team of research and industry partners that have banded together to enhance Australia’s recycling capability. Brought together by the NSSN, researchers from the University of Sydney, University of Technology Sydney (UTS) and University of New South Wales (UNSW) have collaborated with major Australian companies to develop novel solutions for sensing and treating residual contaminants on HDPE milk bottles. Project partners and industry experts involved include Labelmakers Group, Dairy Australia, Bega, Lactalis, as well as Saputo. Led by PEGRAS Asia Pacific, the industry-driven collaboration aims to support the transition towards a thriving circular economy. PEGRAS director and technology consultant Ian Byrne said the partnership took roots in 2017 when the Labelmakers Group approached PEGRAS about the glue used in labels and the impact they may have on recycling milk bottles. “The problem relates to the glue sticking the labels to the milk bottles made out of HDPE. The label is only about the thickness of a strand of hair and consists of five separate layers. About 12.5 per cent of the milk bottle surface is covered with label material that is stuck on with pressure sensitive adhesive. The glue is very hard to wash off when the milk bottle is being recycled as if we try to wash the adhesive off the flake, the adhesive permeates the entire system,” he said. 26 ProPack.pro June 2021
1. Jessica Walters (Labelmakers), Graeme Lang (Labelmakers), Dr Thomas Maschmeyer (University of Sydney) and Ad van Dijk (Bega)
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2. A Prof Yansong Shen (UNSW), A Prof Brian Hawkett (University of Sydney), Dr Melita Jazbec (UTS), Ian Byrne (PEGRAS) 3. Hugh Donnelly (FPC Food Plastics), Dr Stephanus Peters (PEGRAS), and Graeme Lang (Labelmakers) 4. Prof Benjamin Eggleton (NSSN, University of Sydney), Dr Donald McCallum (NSSN), Charles Watson (TRMC), Ivan Chua (NSSN), and Dr Tomonor Hu (NSSN)
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5. Gabrielle Upton (NSW MP) officiated the event
As such, Byrne said a QC method that yields an accurate measure of glue contamination was needed, in addition to finding a way to get rid of the glue before it permeated the system. The aim of the research project was to increase the recycling of plastics by sensing and treating label contamination. Fast forward four years and the partnership has developed a world-first for sensing residual glue levels on recycled HDPE, involving HDPE with labels and glue attached put through an impact delamination process to remove the labels and glue from the surface. A new chemical washing technology has also been developed to remove most residual glue from a commercial HDPE feed. The new QC method was then used to determine the glue content of the final HDPE. This method takes into
account the non-uniform nature of the recycled flake. A provisional patent covering this technology is being prepared. “Reaching this target requires an ongoing collaboration between industry, government and academia. Labelmakers has since designed four trial variations, printed 80,000 labels, and used over 4,000L of wash solution to remove them,” Byrne said. “But the speed of design upcycle needs to be increased. Labelmakers will be transferring testing to a project test read, currently under construction.” A new mechanical separation technology is also under development, based on impact delamination, to remove most of the labels and glue without washing. Labelmakers Group technical manager Graeme Lang said making www.propack.pro