Multilayer process: the addition of the plastic film was the first step for making brick containers impermeable to liquids and heat-sealable. Inside the nineteen sixties, an aluminum foil started to be added for the cardboard container to guarantee far better security and increase the shelf lifetime of the packaged solution. https://gabletoppak.wordpress.com/2025/01/09/gabletop-pak-pioneering-sustainable-packaging-solutions-for-a-greener-future/