Multilayer method: the addition of a plastic film was the first step to make brick containers impermeable to liquids and heat-sealable. While in the nineteen sixties, an aluminum foil started to be additional to the cardboard container to guarantee superior protection and lengthen the shelf lifetime of the packaged product. https://customgabletopcarton.blogspot.com/2025/08/water-in-paper-pak-smart-sustainable.html