Multilayer method: the addition of the plastic film was the initial step for making brick containers impermeable to liquids and heat-sealable. Within the nineteen sixties, an aluminum foil began to be additional on the cardboard container to be sure improved safety and lengthen the shelf life of the packaged solution. https://ecowaterpackaging.blogspot.com/2025/03/paper-bottle-manufacturers-gabletop.html