Multilayer Program: the addition of the plastic film was step one to help make brick containers impermeable to liquids and warmth-sealable. Inside the sixties, an aluminum foil started to be added to the cardboard container to be certain much better safety and prolong the shelf lifetime of the packaged product. https://share.evernote.com/note/9cc8e768-8134-5d9e-0f2c-09673b48b645