Multilayer Technique: the addition of the plastic movie was the first step for making brick containers impermeable to liquids and heat-sealable. From the 1960s, an aluminum foil began to be added on the cardboard container to be sure much better safety and prolong the shelf lifetime of the packaged product. https://ecowaterpackaging.blogspot.com/2025/03/paper-bottle-manufacturers-gabletop.html