Multilayer method: the addition of a plastic film was the first step to create brick containers impermeable to liquids and heat-sealable. Within the 1960s, an aluminum foil started to be added to the cardboard container to make sure far better safety and lengthen the shelf life of the packaged product. https://ecofriendlypackagingwater.blogspot.com/2025/05/shaping-sustainable-future-with-eco.html