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Metal products require protection from corrosion during
transit and storage, for which generally Polyethylene film containing
special additives, called Volatile Corrosion Inhibitor (VCI), is
used. VCI film contains volatile chemicals and gets deposited on
the surface of metallic products to prevent corrosion. The major
sectors that need such film are: automotive, defence, electrical
and electronic.
Earlier, Nitrites were used for VCI film. However, findings indicate
that Nitrites are carcinogenic, hence their usage has been discontinued.
Currently, the variants of Nitrites are used in VCI film. These
additives are quite expensive and are difficult to incorporate in
the film. Hence VCI film is a speciality product, sold at approximately
US$5/kg. Such VCI film is available as a bag or in the form of shrink
film. Due to the dangers of damage to the environment and potential
risk of cancer from few of the volatile additives, another technology,
originally developed by Bell Laboratories, USA is used. This technology
is based on barrier materials, with copper being used as the moisture
barrier. However, currently, VCI film has a higher market share
of this application. The barrier film could provide better and longer
protection but at a higher cost as compared to VCI film. This speciality
film requires significant care during manufacture of PE films using
a VCI masterbatch. The handling of VCI masterbatch requires clear
understanding of its hazards. Respiratory mask and other protection
gear are essential for handling the masterbatch. VCI film, though
not as sensitive, require handling by gloves and good ventilation
in the plant.
More information about VCI film can be obtained from its major
manufacturer called Cortec Corporation, St Paul, USA.
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