Extrusion coating and lamination of aluminium foil are very efficient and commonly used converting procedures, with or without corona-treatment. Most of the foil is put through an annealing process, generating an optimised surface for unwinding ability at high speed, wettability and adhesion. Aluminium foil’s surface tension mostly lies far beyond that of any other substrate to be converted. There are, however, converters who insist on and others who refuse the use of corona treatment. Different aluminium foil surface qualities, non-annealed and annealed ones are coextrusion-coated with different grades of acid copolymer as bonding resin and polyethylene or a sealable top layer. Extrusion coating conditions and corona-intensities have been varied and surface changes by the corona treatment are described. The effects upon adhesion and bond durability when stored with filled good are discussed.
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