Application of the magnetron activated deposition process (MAD-process) to coat polymer films with alumina in web coaters

Abstract

There is an increasing interest in thin transparent oxide layers as permeation barrier for packaging applications. Nevertheless, these products are entering high volume industrial production only slowly. One main barriers to the broad introduction of thin oxide layers are the high investment costs for a new production plant. A possible way to promote the commercialization of aluminum oxide layers is to modify already existing roll coaters. This concept leads to three technological tasks: (a) reactive evaporation of aluminium from boat evaporators at high deposition rates; (b) process control for quality assurance of alumina coatings; (c) plasma-activated deposition at high deposition rates and large web width. From this point of view, the plasma activated deposition process of alumina layers in a conventional roll coater has been studied at high web speeds.