MATERIALS | COMPATIBILISERS
be incorporated in food packaging applications. In a recent development, Evonik has invested in Interface Polymers – a UK manufacturer of high-performance additive technology to simplify processing and recycling of plastics – through its Sustainability Tech Fund. Interface Polymers says that it is observing
Above: Interface Polymers is receiving increasing requests from companies to solve the problem of how to recycle mixed plastics as well as plastics contaminated with other packaging media
“Typically, unsaturated monomers such as maleic anhydride (MSA), 2,3-epoxypropyl methacrylate (GMA), methacrylic anhydride (AA), which contain additional functional groups, are grafted onto the polymer by a radical addition mechanism. In this way, a large number of functional polymers with completely different properties can be created. The length of the polymer and the amount of grafted monomer can also be controlled during the reaction. A new product that BYK plans to launch is grafted PET based on recycling feedstock. The product can be used as a novel high-performance polymeric modifier to improve the intrinsic viscosity of recycled PET.” Evonik has developed novel compatibilisers for
recyclates. The company says that once recycled plastics have been cleaned, sorted and recovered they must be processed into new parts; however, two major problems exist. The first is that imperfect sorting results in incompatible plastics being mixed together, and the second is that during reprocess- ing the recycled plastic begins to release some odour that limits the end uses it can be applied to. For the first issue, Evonik has developed Tego Cycle CP 320 as a compatibiliser for polyolefins, polyes- ters and polyamines and Tego Cycle CP 310 as a compatibiliser for PP and PE. Incompatible impuri- ties in recycled plastics can have disastrous effects on the material properties, and the Tego Cycle CP products significantly improve the mechanical properties of recycled plastics that have been or could be contaminated this way. For odours released during polymer reprocessing, Evonik offers Tego Sorb products as a solid masterbatch in PP or PE or as a liquid. It says Tego Sorb is extreme- ly effective at reducing malodour caused by recycled polymer reprocessing, especially those caused by sulphur compounds or amines. Malo- dour absorption allows for more recycled plastic to
22 PLASTICS RECYCLING WORLD | May/June 2023
increasing requests from companies across the world to solve the problem of how to recycle mixed plastics as well as plastics contaminated with other packaging media. “As companies look to make their packaging more sustainable the option to recycle the packaging they already use, that has been optimised for performance and cost over many years, is the best solution,” says Simon Waddington, Business Development Director. “However, they are finding that the types of compatibiliser available is limited and therefore look to companies such as Interface Polymers with novel compatibilisation to solve the problem. The problems faced are most often in processing the mixed plastic or cross contaminated waste, where di-block compatibilsers offer the best performance to eliminate gels, flow defects and create smooth printable surfaces.”
Film challenge He continues: “The main trend influencing packag- ing is sustainability, so this is driving additives and polymers producers to divert significant efforts into solving the challenges. This is highlighted by the large demand for developmental machines, for example. When we started asking film producers what their issues were, they all stated that it was physical properties of the film. However, the polymer industry reacted quickly to demonstrate that this was not an issue, and we suspect that many companies were guessing at the problems. From actual trials now done with mixed or cross contami- nated plastic packaging the major challenges faced are in processing and surface finish, while the issues with physical properties can be easily overcome. This is where new technology is required to overcome issues with traditional compatibilisers which need to be added at a high level of greater than 10% and can cause processing issues. The new generation of products developed by Interface Polymers are effective at low levels often below 1%.” The company has developed Polarfin grades for
virgin and recycled polymers. The di-block com- patibilisers are suitable for a wide range of mixed plastics, such as PE/PA, PP/PA, PE/EVOH, PP/EVOH, PE/PET, PP/PET, PE/cellulose and PP/cellulose. Waddington adds that one key development has been with a producer of multi-layer PE/PA packaging. Currently, the company recycles
www.plasticsrecyclingworld.com
IMAGE: INTERFACE
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58
