The strategic collaboration between Siegwerk, a German producer of printing inks for packaging applications and labels, and APK AG, a specialist in the production of high-quality plastic recyclate from packaging waste, has delivered its first significant results, the companies report.
Since October 2019, Siegwerk and APK have been working together on ways to close the loop for flexible packaging through better design for recycling.
“For Siegwerk this means providing innovative printing inks and lacquers, which facilitate high-quality recycling – for example by allowing easy de-inking while keeping full performance during the use phase,” said Alina Marm, head of the Circular Economy Hub at Siegwerk. Printing inks are vital for the appearance and functionality of packaging, yet they also manufacturing high-quality plastic recyclate. “The goal of a quality-driven recycling process is to create a recyclate, which is as transparent as feasible and which can once more be reused in packaging applications. Successful de-inking is essential,” Klaus Wohnig, CEO of APK AG, explained.
Over the past months, the research- and development unit at APK AG tested a number of LDPE-film samples printed with yellow, red, black and blue inks from Siegwerk, with the aim of establishing whether APK AG’s solvent-based Newcycling recycling technology could fully remove Siegwerk’s inks from the polymer matrix.
APK’s Newcycling technology consists of a first physical pre-treatment of plastic waste, after which a solvent-based process step is used to purify the polymer from additives such as Siegwerk’s printing inks. The result is a virgin-like recyclate with a smaller carbon footprint and a 47-88% lower emission rate compared to virgin plastic. Unlike in chemical recycling, the molecular structure of the polymer remains intact, thus preserving the energy invested in the polymerisation process. The tested film samples were treated with the Newcycling solvent and dissolved. The obtained polymer solution still contained printing ink-components. The dispersed inks were then removed with a filter unit explicitly designed for the de-inking process step and featuring a very high selectivity level. The de-inking tests of the red, black and blue samples produced a ‘near-virgin’ transparency; in the film with the yellow printing a marginal yellowness remained after the treatment.
"We have mastered a much-discussed challenge for efficient recycling of flexible packaging’, said Ralf Leineweber, Head of Global Technology Development at Siegwerk.
"In line with the principles of the EU Green Deal and the new Circular Economy Action Plan our Newcycling technology aims at closing cycles for flexible packaging solutions that are deemed ‘un-recyclable’ up to now. We aspire to combine environmental benefits of recycling with high-quality performance of the recyclate," said Hagen Hanel, head of the Plastics Recycling Innovation Center at APK AG.