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Plasma Pretreatment of Polymer Films as a Key Issue for High Barrier Food Packagings

 
: Moosheimer, U.; Bichler, C.

:

Surface and coatings technology 116/119 (1999), S.812-819
ISSN: 0257-8972
Englisch
Zeitschriftenaufsatz
Fraunhofer IVV ()
adhesion; Al; AlOx; barrier coating; biaxially oriented polypropylene; BOPP; permeation; SiOx

Abstract
The food packaging industry demands cheap polymer films possessing a high barrier agains permeation of gases, moisture and flavor. Candidates for the most successful materials fulfilling these requirements are newly developed laminates of biaxial oriented polypropylene (BOPP) films containing a thin inorganic barrier layer and possessing an oxygen permeability lower than 3 cm3/(m2/dbar) and a moisture permeability lower than 0.05 g/m2 day). The thin barrier layers are produced by vacuum web coating of BOPP films. In order to achieve high barrier laminates, one key issue along the whole production chain - from film extrusion to lamination - is given by the surface properties of the non-coated films. Non-coated BOPP film surfaces were modified by different kinds of plasma pretreatment and characterized before the vacuum coating process. The functionality - as adhesion and permeation - of coated barrier films and final high barrier laminates was studied as a function of pretreatment parameters. The BOPP homopolymer or copolymer films were either pretreated subsequent to the film production by a standard corona atmosphere plasma or in situ before the vacuum web coating by an oxygen low-pressure plasma. The topography of non-treated and pretreated films was analyzed by atomic force microscopy (AFM) and the chemical surface properties by contact angle measurement as well as X-ray photoelectron spectroscopy (XPS). These BOPP films were vacuum web coated with aluminium (Al), aluminium oxide (AlOx) or silicon oxide (SiOx) and laminated with a two-component adhesive system. Typical pretreatment parameters of BOPP films necessary for high barrier laminates after coating and lamination could be identified.

: http://publica.fraunhofer.de/dokumente/N-522.html