Multilayer system: the addition of the plastic film was the initial step to help make brick containers impermeable to liquids and heat-sealable. From the nineteen sixties, an aluminum foil began to be added into the cardboard container to ensure much better defense and extend the shelf life of the packaged https://share.evernote.com/note/c683562e-b29c-290b-e108-3aef974c977a