PRISM

Plastic Packaging Recycling using Intelligent Separation technologies for Materials or PRISM is a technology being developed by a British consortium to quickly sort different kinds of plastics in recycling processes. PRISM uses fluorescent labels on plastic packages that can be read by high-speed optical sorting machines.

Several high-value materials in plastic packaging are not re-used because it is difficult to sort them. As a result, they end up as residues in recycling facilities. Nearly 77,000 tonnes of food-grade plastic can be separated and reused, according to the consortium.

PRISM aims to solve this by developing fluorescent markers that can be printed on plastic packaging sleeves and labels. The label can be read by an ultraviolent light source fixed inside high-speed automatic sorting equipment.

The process can distinguish between food-grade and non food-grade polymers. It can identify black plastics and tag full-length shrink-sleeves. It helps efficiently sort out polypropylene or PP packaging for food materials, sleeved PET, and high-density polyethylene or HDPE milk bottles. It is complementary to existing NIR technology.

The luminescent materials would be developed from compounds that don’t use rare earth elements and from materials recovered from fluorescent lamp recycling. The labels get completed removed during the recycling process.

The targeted waste streams include food-contact plastics, bioplastics, chemical packaging, automotive plastics, black plastics and different grades of one plastic.

PRISM can be used in existing high-speed optical sorting systems with minor modifications. In pilot runs, it demonstrated 96% purity with yield in excess of 95%, which meets the European Union’s standards for 95% purity in PET food grade plastic.

The partners of the consortium are Nextek, Brunel University, Tomra, CCL, Mirage Inks, Johnson Matthey, Enlightened Lamp Recycling (ELR), Cleantech Europe and WRAP.

In 2015 PRISM received a three-year research grant from the Engineering and Physical Sciences Research Council.