Goods in danger of corrosion must be protected in a “climatic packaging” for sea transport, polar and tropical shipment and during long-term storage. The packed goods are sealed into steamtight Tropac® layer films (aluminium barrier film or polyethylene barrier film) that closes off the packed goods hermetically against the outer air. The inner atmosphere is kept securely below 50 % rh with the volume of TROPAgel. desiccant units calculated accordingly, which adsorbs the residual moisture in the sealed packaging.
TROPACK recommends two material versions of sealing layer films:Polyethylene barrier film as standard packaging for a transport and storage time of no more than 1 year. A 200-µm thick foil with maximum permeability of 0.5 g/m2 in 24 hours and at 23 °C/ 85 % rh (see DIN 55122) offers the required protection.
Aluminum barrier film TL 8135-0003 - is an aluminum sandwich foil that is suitable for a feed and a storage time from one year to five years. Long-term packing must be e.g. sealing in an aluminum sandwich foil, Tropac. barrier layer sandwich foil.
Every film type has a differentiated steam permeability. Therefore, calculation requires consideration of the continually penetrating volume of moisture – see DIN 55474. The following points are important for this:
- Climate zones that are crossed
- Duration of transport and/or storage
- Water vapor permeability of the foil
- Packaging surface in m2 (all 6 sides)