MultiRec (2022)

Packaging is projected to maintain one of the largest target applications for plastics, currently accounting for 39.6 % of the total plastic demand in the EU, fulfilling its functional role to guarantee a high product quality with an attractive appearance for the consumers. However, in the framework of the updated EU directive 94/62/EC on packaging waste, ambitious targets are put forward for the near future: a specific growth of the recycling percentage from 55 % (current) to 70 % in 2030 has been defined for plastic packaging. Striving to a circular economy and countering resource depletion, these challenging requirements are currently provoking a shift from multi-layer packaging concepts to mono-materials solutions. Hence, the extensive (and economically non-viable) separation/sorting schemes and waste stream contamination in recyclates can be largely avoided. More specifically, adding mechanically recycled polyolefin plastic streams into polyolefin packaging films is regarded as a promising route to combat the enormous plastic waste pile ending up in landfills or incinerators. Especially, the re-processing of mono-material polyolefin films, sorted from post-consumer plastic waste, into functional flexible packaging foils for non-food applications, is currently within the technological capabilities. However, even for commodity applications, the recycled foils need to exhibit the appropriate lifetime, mechanical properties, appearance and functional characteristics for their new application. These properties strongly depend on the present additives, also fulfilling a pivotal role in the (re-)processability and the associated degradation of plastics. Therefore, the need to track the concentration distribution and the remaining functionality of these additives in recyclates cannot be underestimated.

In the current call for CORNET/TETRA projects, research institutes over the entire EU will join forces with the packaging industry in the MULTIREC consortium, to showcase to what extent polyolefin packaging (focus on polyethylene-PE) can be reprocessed and how the functional packaging properties and additive concentrations evolve upon subsequent reprocessing cycles. The support, advice and involvement of the SMEs in the flexible packaging sector is indispensable to reach the ambitious objectives, elaborated in the following paragraphs.

1. Multiple mechanical recycling of virgin and waste polyolefin monomaterials (containing at least 90 % of PE) is performed by research partners in Germany and Poland (Fraunhofer Institute for process engineering and packaging IVV, Wroclaw University of Science and Technology, Fraunhofer Institute for Casting, Composite and Processing Technology). They investigate machine processability of recyclates in blown and cast film processing as well as the impact on functionalities as rheological and mechanical properties, sealing behavior, barrier properties and the coefficient of friction, depending on the type and origin of the waste material. The ecological impact (LCA) of reprocessing will also be studied by these research institutes.
2. Knowledge and insights in the evolution and functionality of present additives during reprocessing will be realized by chemical research at the ACC group.  Common polyolefin additives will be selected, and added in a controlled way to the matrix material, whereupon the processing-recycling sequence will be initiated. In the intermediate stages, the composition and functional behavior of the plastics will be analyzed, focusing on melting behavior, crystallinity, molecular weight distribution, the degree of cross linking/rigidity, chain scission/backbiting, oxidation and impurities. The additives will be chosen as such that they exhibit a wide range of molecular weights/boiling points affecting their migration/emission behavior, and correspond to the interests of the participating SMEs. The correlations between the loss of these additives throughout the recycling process and the chemical degradation of the host matrix are targeted, to be further translated in specific processing recommendations.
3. The multi-recycled polyolefin films (see 1-) can also find their application as transport packaging (stretch and/or shrink film) of palletized loads or secondary packaging. Analyzing mechanical properties and transport simulating testing of these reprocessed films are crucial, relying on the test infrastructure and expertise in the research group MPR&S. To increase the understanding in the relationship between reprocessing and application of rPE as transport packaging films (stretch and shrink foils), mechanical and chemical results will be related to each other and compared to virgin material foils.
4. ABSTRACT en LOI - MULTIREC

Project lead:

• Fraunhofer
• MPR&S (UHasselt/imo-imomec)

Project partners:

• ACC (UHasselt/imo-imomec)
• Fraunhofer
• IVLV
• WUST
• West Pomeranian Chemical Cluster “Green Chemistry