Multilayer technique: the addition of the plastic film was step one to make brick containers impermeable to liquids and warmth-sealable. During the sixties, an aluminum foil started to be additional into the cardboard container to ensure far better safety and extend the shelf life of the packaged products. This involves https://share.evernote.com/note/c683562e-b29c-290b-e108-3aef974c977a