Testing DfR against reality using a recyclability assessment framework: A case study on lamination adhesive for...

Laminated films provide essential mechanical, optical, and barrier functions in packaging but often hinder closed-loop film-to-film recycling. This study introduces a recyclability index (RI) framework to quantitatively assess the recycling performance and circularity potential of flexible packaging under realistic closed-loop conditions and evaluates whether a designed-for-recycling polyurethane (PUR) lamination adhesive supports future recycled-content targets. Five mono-material laminates (LDPE, MDOPE, barrier PE, BOPE, and metallized BOPE) and three multi-material laminates (BOPP, BOPA, and BOPET) were mechanically recycled by compounding laminate layers containing the PUR adhesive and reprocessing them by film-blowing extrusion. Processability, mechanical, and optical properties were evaluated and integrated into the RI. A dilution strategy was then applied to assess recyclability under relevant PPWR recycled-content scenarios. The DfR PUR adhesive caused only a limited reduction in recyclability of mono-material PE laminates, with RI decreasing by approximately 14% relative to controls, while stable film blowing was maintained (processability index: 0.92-1.00). BOPE exhibited the highest RI (0.85), whereas LDPE and metallized BOPE showed lower values (0.78), indicating differences among mono-material laminate designs. Multi-material structures showed greater limitations: BOPP achieved moderate recyclability (RI=0.72), while BOPA- and BOPET-containing laminates exhibited severe processing limitations and low RI values (0.18-0.21). These results demonstrate that laminate architecture, rather than adhesive design alone, governs closed-loop recyclability. The RI provides a quantitative tool for identifying design factors affecting recycling performance and supports the development of mono-material structures better suited to future circular packaging requirements.