Transparent Barrier Coatings for Environmental-Friendly Packaging Applications

摘要

The end market for transparent flexible barrier films is larger than for metallized films and currently isdominated by polymeric barrier layers. Some of these coatings are under scrutiny and discussionsince they contain chemicals like chlorine, which are not considered to be environmentally friendly.An alternative for thick polymeric coatings can be a vacuum coating process with a coating thicknessseveral orders of magnitude thinner and in the range of only ～ 10 nanometers achieving the same orbetter barrier properties compared with polymeric coatings. Another advantage of vacuum basedprocesses, the source materials for the barrier layers are usually natural occurring oxides like SiOx orAlOx. By coating on substrates like PLA, fully biodegradable barrier films can be produced.Environmental aspects, barrier and optical properties are all important, but equally important are costaspects, process flexibility regarding different base films and coating robustness to survive the downstream converting processes.