High-Rate Roll-to-Roll Vacuum Metallisation for Flexible Packaging Materials: A Life Cycle Assessment Study

Barrier layers are an essential component of flexible packaging for products susceptible to degradation or spoiling through ingress of water vapour or oxygen, which can readily penetrate conventional polymeric films. Vacuum metallisation of thin films for polymer packaging is widely employed to provide these barrier properties and hence extend the shelf life of the product. However, the environmental impacts associated with producing this metallised layer for packaging solutions are yet to be fully investigated or reported in the literature in the form of a Life Cycle Assessment (LCA). Using 87% primary data derived directly from industry, this study considers in detail all inputs, consumables, and outputs necessary to commercially produce a vacuum-metallised layer onto a high-area roll-to-roll polymer film substrate. A rating of “excellent quality” as per the industry-recognised pedigree matrix, along with validation of the data and acquisition procedures by relevant industrial experts throughout the production chain and adherence to (ISO) 14040:2006 and (ISO) 14044:2006, ensures the highest standards of quality assurance and rigour. The Life Cycle Impact Assessment (LCIA) was performed for impact categories of climate change, freshwater consumption, and energy consumption, using the ReCiPe 2016 midpoint (H) methodology. Whilst the metalliser operation contributed the greatest energy use in the process, half of the climate change emissions and the majority of freshwater consumption were attributed to the raw materials and transportation. It should be noted that other converting processes experience a higher energy consumption (more than double) due to additional drying steps. A comparative LCA study was conducted, employing only secondary data found from publicly available literature and databases. The findings from this comparative study highlight significant overestimation of environmental impact, hence emphasising the importance of using up-to-date primary data wherever possible to reduce uncertainty in environmental impact from LCA.