Abstract
Despite extensive sorting, packaging waste often contains a mixture of different materials that make high-quality recycling difficult, especially in the case of flexible packaging. This is partly due to the widespread use of multi-layer laminates and packaging consisting of different inseparably combined materials. To improve the post-consumer recyclate quality and develop optimised recycling processes, it is important to generate a comprehensive understanding of the composition of the sorted packaging waste streams. Therefore, in this study, polyolefin sorting fractions for flexible packaging waste from three European countries are analysed in detail. By selective extraction of the different plastics, their mass fractions in the waste streams are determined. This shows that the PE-rich sorting fractions for flexible packaging are made up of 85-90% of PE, but also contain a certain proportion of foreign materials. A detailed analysis of the layer structures of various types of packaging also provides information on the prevalence of multi-layer packaging and the polymer and non-polymer materials used therein. This shows that particularly in food packaging, with 63-84% of multi-layer and 50-70% of multi-material packaging, a high proportion of foreign materials is used and introduced into the sorting fractions. These insights provide a valuable contribution to the development of recyclable packaging, potential sorting streams and recycling processes, especially with regard to the challenges of the closed-loop recycling of food packaging.