A cradle-to-grave life cycle assessment of multilayer plastic film food packaging materials, comparing to a paper-based alternative

Abstract

This study evaluates alternatives to polymers with high environmental impact in plastic-based multilayer packaging (PMP). This Life Cycle Assessment (LCA) quantifies energy demand, fossil resource scarcity (FRS), and greenhouse gases (GHG) associated with 14 PMP films, with comparisons to coated paper-based packaging (CPP). Two functional units, one ton and one m³ of packaging, were considered. End-of-life scenarios, including landfilling and incineration, were based on average US use for plastic waste, along with recycling for CPP paper. Production of polyamide 6 (PA 6) has four times the GHG impact of polymers like high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE) due to its natural gas demand, and almost twice that of polystyrene (PS), the second highest environmental burden for a skin layer on a volume basis. Polyethylene terephthalate (PET) is a promising alternative to PA 6, offering improved functionality and reduced environmental impact. As a core layer, ethylene vinyl alcohol (EVOH) has lower impacts than PA 6 in terms of energy (−35%), GHGs (−74%), and FRS (−34%). Among PMPs, HDPE-EVOH, LDPE-EVOH, LLDPE-EVOH, and PP-EVOH have lower environmental impacts while meeting required O₂ and water permeability. CPP production is more environmentally-friendly than PMPs in energy (25–34% improvement), FRS (81–83% improvement), and GHGs (34–62% improvement). Using 75% recovered paper in CPP production improves energy, FRS, and GHG impacts by up to 41%, 16%, and 11%, respectively, compared to using virgin paper. This study offers a framework for layered packaging impact assessments, guiding manufacturers toward environmentally-friendly options that retain essential functions.