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UV plastic sorting R&D gets €1 million grant

A technology platform using invisible inks that can automatically sort food-grade and non-food-grade plastics in recycling streams has received £772,000 (€980,000) in financial support from the UK government.

The cash influx will allow the Plastic Packaging Recycling Using Intelligent Separation Technologies for Materials (PRISM) consortium to continue work over the next two years. Its technology has already been trialled, showing that by adding inks that are luminescent in ultraviolet (UV) light to packaging labels, it is possible to accurately discriminate between different polymer types in mixed waste streams.

This is important, as cross-contamination by as little as 0.1% can impact the quality – and hence price paid – for a recycled plastic.

Different codes can also be used to discriminate between containers made of the same material – like polyethylene terephthalate (PET). Importantly this could allow the rapid sorting of food-grade from other classes plastic at a material recovery centre (MRF), creating a new source for recyclable food contact plastics.

Claire Shrewsbury is packaging programme area manager at the Waste & Resources Action Programme (WRAP), one of nine members of the PRISM group. She says: ‘The new technology could help boost recycling plant yields, and UK plastics recycling as a whole, with more efficient ways of sorting materials such as polypropylene packaging, high-density polyethylene milk bottles and sleeved PET.’

The partners have already reported recycling plastics with a 98% yield and 95% purity in the first phase of its work. The same technique may also have applications in recovering materials from waste electrical and electronic equipment (WEEE).

The next step, which the government funding will bankroll, is to develop a new UV-detectable ink chemistry for PRISM from metal oxides and fluorescent materials from waste light bulbs. One key point to determine is how the inks will endure through a pack’s life, and whether they will breakdown during reprocessing.

Importantly the PRISM approach allows for automatic sensing at high speed and is described by PRISM as low-cost, but it will require a moderate investment in UV sources for MRFs.

The money has been given to the consortium by Innovate UK, and the Engineering and Physical Sciences Research Council (EPSRC), from funds allocated by central government. A similar sum will be devoted to the project collectively from the PRISM partners.

In addition to WRAP, the PRISM project members are: Brunel University, CCL Label, Enlightened Lamp Recycling, Evolve Polymers (until mid-February known as Eco Plastics Recycling), Johnson Matthey, Mirage Inks, Nextek and Tomra Sorting.

This article comes from Food Contact World, which provides exclusive news and analysis on developments in digital print trends, markets, and technologies.