When shipping metal products overseas, one must consider the possibility of product corrosion. Corrosion is a chemical reaction that occurs when a metal surface is exposed to an electrolyte and moisture (and oxygen). Electrolytes are substances that carry free ions such as acids, bases or salts. The higher the level of moisture and ions present, the faster the corrosion.
The most common strategy for retarding corrosion is to keep moisture and or electrolytes from reacting with the metal surfaces. Shipping product by sea brings both moisture and salt into play big time.
There are several methods one could employ to protect cargo from corrosion. The exact method used depends on the product size, configuration, type of metal and the affect that corrosion has on the functionality and appearance of the product. The following are common methods:
Temporary Coatings: Substances can be applied to the product that essentially prevents moisture and salt from contacting the surface. The substance forms a thin layer that can be easily washed off after delivery. This product tends to work well with larger, bulkier parts. The material can be applied by spray, foam or immersion. Since the substance must resist moisture, the washing process usually requires use of a cleaning agent that will break down the substances before it can be washed away. The main disadvantage of this process is that a cleaning operation is required to remove the material after the product is shipped.
Sealed bag or Container: Putting the product in a sealed moisture proof container or bag can reduce the likelihood of exposure to the corrosion producing elements. But is not foolproof when it comes to keeping moisture away. Even if the container or bag is impervious to water, condensation can occur unless the container is vacuumed sealed. Vacuum sealing removes air from the container (along with humidity). Vacuum sealing may be impractical and difficult for some applications. Often desiccants are placed in the sealed container to absorb moisture. Desiccants generally work in small bags, but they can rip or tear during transit handling as well.
Cortec VpCI packaging products offer a near foolproof solution. The VpCI packaging films and bags actually emit a vapor that saturates the air and attaches to metal surfaces. This vapor contains VpCI molecules that bond to the metal surface and prevent the metal from reacting to the surrounding atmosphere. The VpCI saturated air is contained within the Cortec package. Once the bag is opened the VpCI molecules dissipate into the open air. There is no need to clean metal surface.
The advantage of the Cortec VpCI products is that there is no added labor in packaging or un-packaging and no special treatment of the product before or after shipment is needed. Most of these types of products are getting packaged anyway, so there are no added steps in the packaging process. The VpCI packaging materials are available in the form of pouches, shrink film, foam sheets, poly sheeting, bags and paper. All Cortec products are safe for humans as well as for the environment.