Multilayer method: the addition of a plastic movie was the first step to make brick containers impermeable to liquids and heat-sealable. While in the 1960s, an aluminum foil started to be extra for the cardboard container to ensure far better protection and extend the shelf life of the packaged merchandise. https://sustainablewaterpackaging.car.blog/2025/01/09/gabletop-pak-durable-and-eco-friendly-packaging-for-every-need/