Fluoroplastic films have been exposed to natural and artificial weathering tests for over 30 years. In the process, these films have demonstrated that use over such a long period has no significant effect on their usability. The tests are carried out under high UV stress and humidity and with exposure to pollution. The UV-resistant films, which are naturally transparent without additives, remain unaffected and thus fulfil their role as protective films.
The films are largely self-cleaning (similar in their behaviour to Teflon, for example). This means that air pollution, bird excrement and other deposits will be washed off the next time it rains. Complex roof access systems for cleaning are not required and generally high cleaning costs are not incurred.
The most widely used ETFE film can be employed in a wide temperature range, is non-flammable and impresses with its extremely good mechanical properties (elongation at break at 20-160 °C about 150-200 %; tear resistance 180 N/mm). As described above, its resistance to weathering is outstanding and its transparency is around 95 % or more, depending on the thickness of the film. The penetration of UV radiation is only slightly reduced (greenhouse). Flammability is very low (DIN 4102-B1) and there is no dripping of material as it burns.
The high elasticity of the film means that destruction by hail is impossible. In the event of a fire, the film melts with no flammable dripping. Shading can be provided by controllable film layers in the cushions (covering in various patterns to make a completely closed surface).
Overall, roofing (membrane constructions) made of fluoroplastics offers many advantages and can provide cost savings of 30-50 % compared to traditional transparent roofing solutions. And for several years now, membrane construction has no longer been a difficult building task. Several research studies have shown that roofs made of “flexible glass”, façade elements and climate envelopes made of ETFE films are all achievable and can be costed. The behaviour in terms of structural physics has been extensively researched by the Fraunhofer IBP, among other bodies, and this complements the many years of experience of companies that have been planning and making membrane structures for a long time now.
CMC Klebetechnik has an adhesive tape (CMC 77700) in its range which can be used to easily repair damage to these film roofs/canopies. The base film is the tried and tested ETFE film from Nowofol. The adhesive used is adapted to the high demands and to surfaces in need of repair that are not particularly receptive to adhesive.
Thanks to the high transparency, virtually invisible repairs are also possible in other base materials such as glass-fabric-reinforced PTFE or PVC-coated polyester fabrics (no doubling of translucent material, which would make the repair visibly darker). The adhesive tapes are also used as abrasion protection, reinforcement and textile repair tape.
Other films from the portfolio of CMC Klebetechnik that are used for architectural applications include ageing-resistant, light-fast polyurethane films (CMC 63630). These have an extremely abrasion-resistant surface and they are very stretchable. They also have high water vapour permeability.
These highly transparent PU films are frequently used as surface protection where there are mechanical loads or to prevent creaking. They are not suitable as clamping film, however, because of their low thermal resistance up to about 120 °C and the associated softening.
Polymethyl methacrylate (also known as acrylic glass or Plexiglas®) is a glass-like plastic, the inherent properties of which give it high resistance to ageing, a very low tendency to yellowing and good resistance to weathering. CMC Klebetechnik offers a film made from this material, the surface of which is also treated with a thin fluoropolymer layer, giving it outstanding anti-graffiti and dirt-resistant characteristics. It is therefore possible to protect e.g. aluminium panels against weathering permanently and almost invisibly.
Teflon and glass-fabric-reinforced Teflon films (CMC 76700, CMC 75100) can, of course, also be supplied as adhesive tape. The disadvantage is the lack of transparency, but the extremely high mechanical strength stands out in the glass-fabric-reinforced film, which means that such films can easily be used as clamping films.
Adhesive tapes made of THV or FEP films can also be made, if required. In addition to their extreme durability, THV films have the advantage that they are also available as in high material thicknesses (e.g. 0.5 mm).
You can find information about the correct handling of adhesive tape rolls made of CMC 77700 here.
The information above and our technical advice on applications, whether verbal, written or as the result of experiments, is given to the best of our knowledge but is non-binding. Our advice does not exempt you from checking our latest information – in particular our datasheets and technical information – and our products in relation to their suitability for the intended processes and purposes.