Multilayer technique: the addition of the plastic movie was the initial step to make brick containers impermeable to liquids and warmth-sealable. From the nineteen sixties, an aluminum foil started to be extra towards the cardboard container to ensure much better security and prolong the shelf life of the packaged product. https://gablecarton.blogspot.com/2025/02/the-growing-demand-for-eco-friendly.html