Multilayer technique: the addition of a plastic film 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 defense and increase the shelf lifetime of the packaged item. http://cartongabletop.car.blog/2025/10/09/leading-gable-top-carton-manufacturers-eco-friendly-water-and-dairy-packaging/