VCI Paper or VCI Poly Bags?
From strictly a corrosion inhibitor standpoint, paper has been a better inhibitor of rust due the way that VCI is contemporarily coated onto the paper, and is very quickly released into the air and onto the metal product. Due to its characteristics and the immediate availability, VCI paper is able to protect a part quicker coming off of a paper, than polyethylene. This does not mean that VCI poly is not an excellent product. However, from a pure rust inhibitor issue, paper has proven to be slightly more effective especially in terms of quick protection for metal parts. This is particularly important for metal parts that are porous such as cast iron, and metals that are prone to flash rust or quick corrosion.
VCI poly film has several advantages over VCI paper as a corrosion inhibiting packaging medium. The biggest advantage is that it provides a moisture barrier in addition to corrosion inhibiting properties. VCI poly bags also offer the easiness for usage by directly placing a metal product into a treated VCI poly bag. VCI poly bags provide medium long term protection against rust and corrosion, for 1 year maximum. Moreover, VCI poly bags are also transparent hence product can be easily identified, inspected, inventoried, etc, without the need to remove them from the VCI. This is something that VCI paper lacks of. Therefore, to identify which one is better between VCI paper and VCI poly it depends entirely on the specific application, needs, priorities and preferences. And in some conditions, the best solution might be to combine both VCI paper and VCI poly bags.