Multilayer technique: the addition of the plastic movie was the initial step to help make brick containers impermeable to liquids and heat-sealable. In the 1960s, an aluminum foil started to be added to the cardboard container to guarantee much better safety and prolong the shelf life of the packaged merchandise. https://wateringabletop.home.blog/2025/10/09/gable-top-cartons-for-milk-water-and-beverages-recyclable-renewable-and-reliable/