Siegwerk, a provider of printing inks, and APK AG, a specialist in the production of plastic recyclate from packaging waste, successfully completed de-inking trials of twofold printed LDPE-films leading to developing a technology enabling efficient recycling of flexible packaging.
‘Design for recycling, ideally enabling product to product recycling, is crucial to closing the loop for flexible packaging. 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 circular economy hub at Siegwerk.
In spring 2020 the R&D unit of APK AG tested several LDPE-film samples, which had been printed twofold with Siegwerk’s yellow, red, black and blue inks. The test series aimed to establish, whether the Newcycling, a solvent-based recycling technology could fully remove the inks from the polymer matrix.
The film samples were dissolved with the Newcycling solvent. The obtained polymer solution still contained printing ink-components, which were then dispersed and removed with a filter unit featuring a very high selectivity level. The tests of the red, black and blue samples produced a ‘near-virgin’ transparency, with yellow ink leaving a marginal hue after the treatment.
‘We consider the entire life cycle of the packaging, from design, to use phase and finally recycling. We are very pleased that printing inks from Siegwerk have proven to be suitable for solvent-based recycling processes. We have mastered a much-discussed challenge for efficient recycling of flexible packaging,’ said Ralf Leineweber, head of global technology development at Siegwerk.
‘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,’ added Klaus Wohnig, CEO of APK AG.
In line with the principles of the EU Green Deal and the new Circular Economy Action Plan the Newcycling technology aims at closing cycles for flexible packaging that are currently deemed un-recyclable.
‘We aspire to combine environmental benefits of recycling with high-quality performance of the recyclate,’ added Hagen Hanel, head of the Plastics Recycling Innovation Center at APK AG. ‘Newcycling comprises a step of physical pre-treatment of plastic waste, which is also done in conventional mechanical recycling processes. After this we add the solvent-based process step, which purifies the polymer from additives, such as printing inks from the cooperation partner Siegwerk. The result is a virgin-like recyclate. In contrast to chemical recycling the polymer’s molecular structure stays intact the entire process. Consequently, the energy that has been invested into polymerization is preserved.’