Extrusion International 1-2022

38 Extrusion International 1/2022 RECYCLING – FROM THE RESEARCH Printing inks have a major impact on the recyclability of plastic fi lms, the recycling process, the quality of regranu- lates as well as their processability. The PrintCYC initiative started two years ago to investigate this impactmore close- ly and drive circular economy. Today, the initiative is once again providing insights into its research work: Currently focusing on the impact of pigments on the recycling pro- cess, PrintCYC has found that standard pigments for fl exo- and rotogravureprinting showexcellent compatibilitywith recycling and enable recyclates comparable to virgin fi lm. This opens a wide range of reuse possibilities in different fi lm and packaging applications. The PrintCYC consortium was established in 2019 to sup- port the transformationof printedpolyole fi ne-basedpack- aging fi lms towards a circular economy by evidence-based industrial trials. Key stakeholders are leading machine manufacturers such as Brückner Maschinenbau, Erema, Kiefel and PackSYS Global, the printing ink manufacturer hubergroup Print Solutions, and Profol, one of the market leaders for PP cast fi lms. The initiative is coordinated by Dr Annett Kaeding-Koppers, an independent packaging ex- pert and sustainability consultant. PrintCYC is connected to converters and in continuous dialogue with brandowners, recyclers, and platforms such as Ce fl ex and ForumRezyklat to discuss and share results. In the starting phase of the project in 2019/2020, Print- CYC successfully produced PP and PE fi lm and packaging samples containing more than 50%of recyclate from post industrial sources. Focusing on the recyclability of the bind- ers NC (nitrocellulose), PU (polyurethane) and PVB (polyvi- nylbutyral), the initiative identi fi ed the binder PU as most temperature resistant and, thus, as best recycling-ready solution for mechanical recycling without de-inking. At thebeginningof this year, PrintCYC started into thenext project phase, investigating the impact of pigments on the recyclability of printedpackaging fi lms. Inorganic pigments are mostly temperature stable and therefore supposed to be recyclable without degradation. However, organic azo- pigments like most standard red and yellow pigments are more temperature sensitive and might re-split into critical components. The pigments yellow (Pigment Yellow 17) and red (Pigment Red 57:1) are commercially available standard pigments for fl exo- and rotogravure printing and were selected for the recycling trials. Both pigment types showed excellent recyclability, leading to odour- and defect-free, colour-stable PP recyclates. The material properties of the coloured recyclates were analy- sed technically and analytically. After the fi rst recycling loop, PrintCYC found no signi fi cant impactonmaterialpropertiescomparedtovirginreference. Based on a speci fi cmigration screening test, the renowned Swiss quality testing laboratory SQTS evaluated the PP recy- clates according to the limits of the Commission Regulation (EU) No 10/2011 and Swiss Ordinance 823.023.21 on mate- rials and articles in contact with food. The positive results open awide range of reuse in different fi lmand packaging applications. For the next project phases, PrintCYC is looking for part- ners to test and evaluate closed loop printed PP packaging scenarios and to further improve relevant design for recy- cling guidelines. PrintCYCstarted inMarch2019. The initiativewas launched by a group of companies within the value chain of printed fi lms. The acronym PrintCYC stands for printed polypro- pylene (PP) and polyethylene (PE) fi lms for mechanical re- cycling. AKK INNOVATION Dr. Annett Kaeding-Koppers annett.kaeding@akk-innovation.de Research Evaluates the Impact of Printing Inks on Recyclability of Plastic Films PrintCYC provides important input for design for recycling guidelines