Multilayer process: the addition of the plastic movie was the initial step to make brick containers impermeable to liquids and warmth-sealable. While in the sixties, an aluminum foil started to be included on the cardboard container to ensure much better defense and increase the shelf life of the packaged product. https://wateringabletop.game.blog/2025/09/24/water-in-sustainable-pak-a-choice-that-protects-generations/