Multilayer technique: the addition of the plastic film was step one to help make brick containers impermeable to liquids and warmth-sealable. In the 1960s, an aluminum foil began to be included into the cardboard container to make sure much better safety and lengthen the shelf life of the packaged merchandise. http://cartongabletop.car.blog/2025/01/09/gabletop-pak-leading-the-way-in-sustainable-packaging-solutions/