High-Speed, Low-Cost ALD Barrier Film on BOPP Web for Commercial Packaging Applications

Atomic layer deposition (ALD) has been widely shown to produce ideal barrier materials because this technique yields coatings with unique properties, such as extremely conformal, pin-hole free coverage, and high density with low coating stress.  It has been reported that ALD is compatible with numerous substrates, including polyesters.   Polyesters are suitable for some commercial packaging applications, but polypropylene is often preferred due to cost advantages.  Polypropylene can be challenging to grow oxide films on since it consists of only carbon and hydrogen, and notably lacks reactive oxygen sites that polyesters have.  As a result, there have been few solutions for vacuum-coated, transparent barrier oxide films on polypropylene web.  In this paper, we demonstrate a high-speed, low-cost process that utilizes plasma-enhanced ALD to deposit a transparent barrier film on BOPP suitable for commercial packaging applications.