Recycling of multilayer food packaging waste: Techniques, applications, and future prospects: A review

The use of multilayer flexible food packaging has fundamentally revolutionized the global food system by allowing the product to have an extended shelf life, safer storage and highly efficient distribution of packaged foods on a scale never experienced before. However, the complexity of material that makes such performance in service creates immense difficulties at the end of the service since the combination of several polymers, barrier layers, adhesives, and inks place harsh demands on recyclability. Because of this, bulk post-consumer packaging of snacks is often not recycled through standard recycle streams and instead goes to landfills, incineration, or scattered about in nature. This review critically examines the main recycling options that can be used in the recycling of packaging waste, and they include mechanical recycling, chemical recycling and newer upcycling avenues. The most practical but least energy-intensive recycling method is mechanical recycling, which has limitations due to polymer incompatibility, contamination and degradation of material during recycling. Another path that is provided through chemical recycling is the production of complex laminates into fuels, monomers and virgin-equivalent polymers, though barriers in terms of energy requirements, expenses, and integration of the process still exist. Also, increased upcycling and hybrid recycling designs are addressed as a possible measure of producing functionalized polymers, customized blends and specialty materials with previously unrecyclable waste. The review also explores diverse applications in infrastructure and high-value polymers while establishing a rigorous framework to evaluate the Technology Readiness Levels (TRL) and Operational Expenditure (OPEX) of recycling routes. It identifies the industrial shift toward mono-material design-for-recycle structures as a primary solution to material incompatibility. Ultimately, the study highlights the role of integrated systems and policy in fostering a circular economy and reducing the environmental impact of multilayer packaging.