COATING OF COMPLEX POLYMER FILMS ON PACKAGING STEEL

摘要

In metal food packaging, there is a growing demand of polymer coated materials, in order to avoid lacquering processes at the can maker. For this purpose, Corus has developed processes where ECCS and tinplate can be coated with e.g. PET or PP by (direct) extrusion coating or by film coating. In order to ensure sufficient adhesion of the coating to the steel strip, often high processing temperatures are required. Most commonly used is ECCS as a substrate. In the case where specialty films with designs (e.g. holographic or reflective) or where combination of stable and less stable films are used, this often results is a relatively small processing window. This paper describes two systems where enlargement of the processing window was required. The emphasis of the work lies on improvement of thermal stability of the base films. It was shown that specific combinations of polymer films and steel often require specifically modified films and that cooperation with film suppliers is often the key to success.