It is used in conjunction with desiccant salts precisely to prevent moisture from oxidizing the metal on long ship voyages, but is also used for long-term protection of machinery and other products, for example, for storage if long-term storage is planned.
This material is mainly composed of aluminum and polyethylene. Depending on the manufacturer, the proportion of each material and even the type of plastic used may vary. For example, sometimes polyester, PET plastic or polypropylene are added. As for polyethylene, it can be of high or low density.
Some barrier materials have more plastic than aluminum or vice versa. The quality and correct protection of the product will depend to a large extent on the total thickness of the barrier film from which the bags are made and how many grams it weighs per square meter, as well as the proportion of aluminum it contains. The more aluminum the material contains to the detriment of plastic, the lower the vapor transmission inside the container.
This material is waterproof and resistant to external factors such as ultraviolet rays.
Generally we can find this material in rolls whose measures can vary according to the customer’s needs, although it is also common to find manufacturers and companies that sell ready-made bags with the measures that the customer deems appropriate.
The aluminium foil barrier bag can also be vacuum sealed if desired, with the help of special machines that absorb oxygen from inside the bag. In this way, the product is better protected against oxidation.
There are several ways of sealing this bag. As its name suggests, the most common way is with heat, although we can also opt for plastic closures that seal the container.
This material can also be printed, so it is common for a company to print its own corporate logo, as well as the specifications of the material and the temperature to which it must be subjected for sealing.
This material must be manufactured in compliance with DIN 55531-1, which is the German and European standard in general.
Other world standards equivalent to this norm that can be found are the following:
- USA: MIL-B-131.
- France: NF H 00310.
- Germany (military classification): TL 8135-0003.
- United Kingdom (military classification): DEF STAN 81-75/1.
To conclude, it is convenient to point out the main difference between aluminum barrier material and other plastic materials that we will see later, such as shrink film or VCI. For long boat trips, adverse weather conditions or long storage periods, aluminum is the most convenient option for the correct protection of the product against plastic compounds, since it is much more resistant.