Multilayer process: the addition of the plastic film was the first step to generate brick containers impermeable to liquids and heat-sealable. In the nineteen sixties, an aluminum foil began to be added for the cardboard container to be sure improved safety and lengthen the shelf lifetime of the packaged products. https://customliquidsoappackaging.blogspot.com/2025/05/sustainable-soap-packaging-for-greener.html