Circular Economy Concept with PA-Recyclate Introduced at K 2022
During K 2022 W&H introduced several sustainability concepts. With the focus on recyclable solutions or solutions using recyclates several applications have been presented. The joint project with BASF and DOW on PA-Recyclate demonstrates for the first time the recyclability of barrier or high barrier films.
In recent years, the issue of recyclability has become increasingly important in the packaging industry. Especially products with barrier function pose great challenges when it comes to recyclability. Polymers like PA or EVOH are required to extend the shelf life of valuable goods such as food. So far, these polymers have not been known to be recyclable. The project partners BASF, DOW and Windmöller & Hölscher addressed this challenge by exploring a number of strategies, that led to the development of an industrial grade PA recycling. In order to prove that barrier films with PA are recyclable and can be reprocessed to high quality barrier films again, the project partners adopted the following approach:
Several 9-layer barrier films containing PA6, CoPA, EVOH and PE were produced from virgin resins in the technical center of W&H. These films were recycled in a standard repelletizing process. To optimize the quality of the recyclate further, the use of compatibilizers was investigated. In a second step, the recycled material was incorporated into the core layer of a 3-layer film for general packaging applications. The processability of the recycled material in the blown film process was very stable. The optical and mechanical properties of the films were comparable to virgin formulations, even though they contained approximately 16-21% of recycled content.
The outcomes of these trials were very convincing. “Flexible food packaging will always require high oxygen barrier. The results of this project prove the recyclability of multi-material barrier films. Depending on the recycled content, the extruded films in the secondary process show excellent processability on W&H machines. By the use of compatibilizers, the properties of the re-extruded films are very consistent.” comments Martin Backmann, R&D Director Business Unit Extrusion at W&H. Following this research co-extruded PA films were removed from the list of incompatibilities for recycling by the German Environmental Agency in September 2022.
