Multilayer technique: the addition of the plastic film was step one to help make brick containers impermeable to liquids and heat-sealable. Inside the nineteen sixties, an aluminum foil started to be additional on the cardboard container to be certain improved protection and prolong the shelf life of the packaged products. https://sustainablewaterpackaging.car.blog/2025/08/10/the-packaging-industry-has-been-changed-by-water-in-sustainable-pak/