Alumitex VCI Paper for Aluminum Corrosion Protection
Recently we have received several inquiries regarding the shelf life and useable term of VCI paper.
Specifically the question was asked as to whether VCI evaporates (sublimates) away when the VCI products are left exposed, indoors prior to their use for corrosion control of parts.
The correct answer is yes, but at a regulated rate of dispersion. This inherint property of VCI is necessary in order for the VCI to protect metals from corrosion. This is why vapor corrosion inhibitors are very effective for corrosion protection while parts or equipment is exposed to variable conditions during shipping & storage.
Storage of VCI Materials
In the case of VCI materials on rolls, the VCI in the inner layers of the rolls should be fine for at least 8 to 12+ months storage given average plant storage conditions in a plant in North America. In the original box and under most ambient conditions (indoors) the shelf life is 24 months + an "in use" period. Temperature and humidity affect the rate of the VCI depletion.
Generally speaking as the ambient temperatures and relative humidity is increased, the rate of release of the VCI from any VCI packaging or device increases. The rate of release of the VCI accelerates above 65 degrees F and 65 percent humidity.
Storing VCI paper or other VCI material on rolls, in the original container below 65 F is ideal. For extended periods of storage (beyond 18 months) placing the VCI paper or other VCI product with its original container inside a vapor barrier bag greatly increases the storage life of the corrosion control VCI products. Typcial vapor barrier bag materials include: 4 mil thick or greater plastic film, co-extruded plastic film, foil laminate or metalized bags. A double layer of a mono LDPE bag (double bagging) is good for this purpose. For an even longer shelf life, place the entire pack in a cool storage area, such as an air conditioned room.
Aluminum Parts Storage
Alumitex VCI Paper is a great interleave for use for aluminum, however depending on the intended storage period, transit times, time continguencies and the anticipated package exposure to ambient/environment conditions an outer layer VCI bag or VCI container liner is recommended. See this presentation for more information: VCI Corrosion Protection Packaging Design