Multilayer process: the addition of a plastic film was the initial step to produce brick containers impermeable to liquids and heat-sealable. While in the sixties, an aluminum foil began to be added towards the cardboard container to be sure improved protection and extend the shelf life of the packaged solution. https://dairycartonsustainability.blogspot.com/2025/06/greener-today-sustainable-carton.html