Multilayer plastic, or MLP, is packaging made of several layers of different materials bonded together, for example PET, polyethylene, polypropylene, aluminium foil or paper. Chip packets, biscuit wrappers, sachets and laminated pouches are typical examples.
Each layer has a job: a barrier against oxygen and moisture, strength, printability or heat sealing. The combination protects food very efficiently, but the layers cannot easily be separated, so MLP is the hardest plastic packaging to recycle mechanically. In India it has its own EPR category under the Plastic Waste Management Rules. Much of it currently goes to co-processing in cement kilns or waste-to-energy. The longer-term answer is design for recycling: single-polymer structures that deliver similar performance.
