Many industrial sectors today use foil coatings on aluminum surfaces for temporary protection against damage. They are also frequently used in architectural applications. However, if film or adhesive residues remain on coated or anodized aluminium, this has a negative effect on the visual appearance. This can also reduce the adhesion properties of the surface. The Verband für die Oberflächenveredelung von Aluminium e. V. (VOA - Association for the Surface Finishing of Aluminum), together with its member companies and specialist companies from its network, addressed this issue and carried out extensive tests with various films on finished aluminum surfaces.
Collected expertise in condensed form
The association has now summarized the collected expertise in the leaflet A 09 B 07 "Protective foiling of aluminium surfaces". It is aimed at anodizers, coaters and other interested parties.
Typical application problems
Application problems are also addressed. For example, the protective films on the building elements are removed at the last moment for the final acceptance of a new building. However, if the film is left on the surface for too long, due to sunlight, strongly fluctuating temperatures or the use of an unsuitable adhesive, adhesive residues remain on the surface after removal. Different influencing factors can interact here and produce different defect patterns. Correction usually requires time-consuming and cost-intensive measures.
Practical experience and simulations
At the suggestion of VOA member companies, the interdisciplinary "Foiling" project group has gathered practical experience and expanded this by simulating different adhesives on the surfaces. They have now been recorded in the new information sheet in order to provide practical tips for companies in the surface finishing industry.
Four powder coatings from two manufacturers tested
The VOA project group's tests on foil and adhesive residues on finished aluminum included four powder coatings from two manufacturers. The workpieces coated with these were provided with four different protective films - designed for the architectural sector - also from two manufacturers, one applied smoothly and one with folds. For an even more meaningful result, the VOA used protective films with different adhesive characteristics. Two tests followed: one was the so-called QUV-B test 313 nm over 350 hours with alternating irradiation at 60 °C and moisture exposure at 40 °C and the other was the climate change test based on the Volkswagen factory standard VW PV 1200. In the end, depending on the pairing of the four different powder coatings and films, the results were sometimes very different. The tests therefore make it clear that many aspects play a role in the selection of suitable protective films, which the VOA addresses in its new information sheet.