Multilayer System: the addition of a plastic film was step one to produce brick containers impermeable to liquids and heat-sealable. During the sixties, an aluminum foil began to be added into the cardboard container to guarantee improved safety and prolong the shelf lifetime of the packaged solution. Taking this idea https://share.evernote.com/note/362ce13f-b851-6e01-c253-74e443569409