Multilayer Method: the addition of a plastic film was the initial step to generate brick containers impermeable to liquids and heat-sealable. While in the sixties, an aluminum foil started to be additional to your cardboard container to make sure greater defense and extend the shelf life of the packaged product. https://www.tumblr.com/sustainablemilkcartons/785844032121208832/sustainable-revolution-from-paper-water-bottle-to?source=share