More than 85 companies and organisations are assessing the viability of digital watermarks for plastics to improve sorting and recycling rates in the EU, according to the European Brands Association (AIM, Brussels / Belgium; www.aim.be), which is managing the research. Participants in the “HolyGrail 2.0” project are said to include Coca-Cola, Dr. Oetker, Henkel, Kraft Heinz, L'Oreal, Nestle, Unilever, and a wide range of plastics producers, retailers, and packaging, recycling and materials processing companies. Consumer goods giant Procter & Gamble (P&G) has been studying the technology since 2019 (see Plasteurope.com of 01.11.2019).

“Digital watermarks may have the potential to revolutionise the way packaging is sorted in the waste management system, as it opens new possibilities that are currently not feasible with existing technologies,” the association said. AIM noted that the “New Plastics Economy” programme of the Ellen MacArthur Foundation (EMF, Cowes / UK; www.ellenmacarthurfoundation.org) has investigated different innovations to improve post-consumer recycling, and digital watermarks were found to be the most promising technology and have passed a basic proof of concept on a test sorting line.

The current research project will take place on a much greater scale and scope, AIM said. Plans include the launch of an industrial pilot to prove the viability of digital watermarks for more accurate sorting of packaging and higher-quality recycling, as well as the business case at large scale.

AIM said one of the most pressing challenges in achieving a circular economy for packaging is to better sort post-consumer waste by accurately identifying packaging, resulting in more efficient and higher-quality recycling.

Digital watermarks are imperceptible codes, the size of a postage stamp, covering the surface of consumer goods packaging. They can carry a wide range of attributes such as manufacturer, plastics type, composition of multilayer objects, and other information. The aim is that once the packaging has entered into a waste sorting facility, the digital watermark can be detected and decoded by a standard high resolution camera on the sorting line, which then – based on the transferred attributes – is able to sort the packaging into corresponding streams.