Rapid disassembly of metalized multilayer food packaging films using acid-based mild formulations

Metalised multilayer packaging films are widely used in food applications due to their exceptional barrier and mechanical properties, but pose major challenges for recycling because of their hybrid structure. These laminates typically combine incompatible polymers, metallic foils, and polyurethane-based adhesive tie layers, preventing clean material recovery. This study investigates acid-assisted delamination as a targeted delamination approach for recycling metalised multilayer films such as PE/Al/Paper, PET/Al/PE, and PP/Al. Laminates with total thicknesses in the range of 60–140 μm were treated using a series of acetic acid–based formulations containing controlled amounts of water and surfactants, optimised to selectively disrupt adhesive interfaces while preserving polymer integrity. The multilayers were found to be thermally stable under treatment conditions. Under optimised conditions, complete separation of PE/Al layers from Tetra Pak material was achieved within 15 minutes, resulting in a material recovery rate exceeding 95%. Formulation parameters and process temperature were varied within a Design of Experiments framework to understand their influence on delamination kinetics.