Multilayer Procedure: the addition of a plastic film was the first step to make brick containers impermeable to liquids and heat-sealable. In the nineteen sixties, an aluminum foil started to be additional for the cardboard container to be sure superior defense and lengthen the shelf life of the packaged item. https://sustainableboxoptions.blogspot.com/2025/04/how-gable-top-cartons-and-paper-water.html