Bedeutung des Kaschierprozesses auf die Sauerstoff- und Wasserdampfbarriere von Verbunden mit anorganischer Barriereschicht

Abstract

The packaging industry replaces more and more heavy packaging materials by lighter materials, especially flexible packaging systems. The total packaging surface of flexible films possessing a high barrier against the permeation of gases, moisture and flavor covers about 16 % of all used packagings. The demanded for high barrier properties by lower material consumption can be achieved by using additional barrier layers, as vacuum evaporated Al, AlOx and SiOx layers. The production chain of high barrier laminates is film production, vacuum web coating and lamination. Along this process chain each single step must be optimized itself and be adapted to the whole chain. Here, each step was analyzed on laboratory as well as industrial scale, whereas the following components were used: substrate films: polyethylene terephthalate (PET) and biaxially oriented polypropylene (BOPP); barrier layers: Al, AlOx and SiOx; adhesives: polyurethane and ORMOCER; lamination films: biaxially oriented polypropylene (BOPP) and polyethylene films (PE). As final process step, the lamination process is the key issue for the barrier of the total laminate against oxygen, moisture and flavor, because on the one hand it can destroy the functionality of the vacuum evaporated barrier layer and on the other hand it can improve the barrier by an order of magnitude due to the synergetic effect between the barrier layer and the adhesive