Foil technology extends chocolate shelf-life

German packaging company VAW has developed a new foil, which it claims extends the shelf-life of chocolate and other foil-wrapped foods.

Working with a standard thickness of 0.0063mm to 0.06mm, VAW has optimised the process of aluminium foil manufacturing even further by investigating the different exertions that foil is subjected to during the extrusion lamination process.

The quality of the foil is already decided during the casting of the aluminium. Until now it has only been by filtering the melt of the aluminium oxide or ceramic particles that the subsequent formation of pores can be avoided, and the strength ensured. Pores are a natural occurrence during the process, but minimising them enhances the capabilities of the foil.

To investigate pore formation further VAW carried tests at its R&D facility. The results of the tests were that the lowest porosity could be achieved with a pressure rubber of medium hardness against a cooling roll with a matt surface. The strip tension at the aluminium foil decoiler should also be kept at low tension to ensure quality.

Further tests showed that the speed of the foil uncoiling also affects the quality - the slower the uncoiling the better the quality. However, so as not to slow production, the VAW research team discovered that changing the angle of the uncoiling stand and increasing the diameter of the guiding rolls enhanced quality without slowing down the process. Additionally the team also found that limiting the gap between the production machine's two rolls to a maximum of 500mm also helped this process.In carrying out the project, VAW has devised a way of improving the quality of aluminium foil without affecting either the cost or the speed of the production process.