Multilayer system: the addition of the plastic film was the first step to create brick containers impermeable to liquids and heat-sealable. During the 1960s, an aluminum foil started to be added for the cardboard container to ensure improved defense and increase the shelf life of the packaged product or service. https://eco-friendlygabletopforoil.blogspot.com/2024/12/embracing-sustainability-with-gable-top.html