Recycling processes for multilayer composites

Nowadays the use of multilayer plastic packaging is wide-spread. Different materials are combined to create packaging with adapted property profiles in terms of shelf-life, resistance, and design. Besides the common packaging plastics PE, PP, and/or PET, plastics with special barrier functions like EVOH, PVDC, or PA provide additional functionalities. Other materials like aluminum or ceramic coatings, aluminum foil, and adhesives may be used as well. Multilayer composites allow a significant reduction of input material, while meeting the high market requirements in terms of product-tailored packaging.

Complete material breakdown and sorting the materials into pure fractions is indispensable for high-quality recycling. Conventional sorting and recycling processes for packaging waste reach their limits with these complex systems of different compositions. Therefore, multilayer composites are currently not subject to high-quality recycling but rather to energy recovery processes.

The aim of this study is to identify and describe the available processing technologies for multilayer composite packaging within the scope of a literature and market research. The required input criteria for the respective processes are presented. The results provide a basis for possible adaptations on material and process level in order to reinsert the valuable packaging materials from multilayer composites into closed-loop material cycles.