a plurality of corona - treated polymeric films , and metal foils or sheets , are alternately arranged and laminated together to form a laminate suitable for e . g . insulating panels . construction of this absolute or near - absolute barrier can be simultaneous or sequential . the metal foils may be of the same type , or may differ . aluminum and steel are preferred metal foils . at sufficient thicknesses , the sheet can be stamped or shaped . both outermost surfaces of the laminate can comprise polymeric film , or both surfaces can comprise metal foils . alternatively , one outer surface can be a polymeric film and the other outer surface can be a metal foil .