Fraunhofer FEP scientists have - over the past year - been commissioning and testing their new atmoFlex system. The developments have been driven by the desire to broaden their capabilities offered to customers by being able to offer processing at standard atmospheric pressure.
In addition to its electron beam system, the process line also provides contactless slot die coating. Further, all of the guide rollers within the conveyance machinery are larger than in comparable plants to minimise the mechanical loading on substrate materials. This has resulted in a wide range of film laminating techniques is available for research and fabrication of custom film composites.
The Fraunhofer FEP scientists said the initial results are promising - for example, they can combine layers that were fabricated using PVD (physical vapour deposition) and fabricated using lacquering processes.
According to the Fraunhofer FEP scientists films used for a wide range of applications can be coated with the new process line, from decorative film for furniture to permeation barriers for food packaging and organic electronics. Specialised modifications to the conveyor design permit the utilisation of both smooth and textured films so that either high-gloss surfaces or decorative finishes can be produced for furnishings, for example.
Figure: Fraunhofer FEP - atmosFlex - standard atmosphere pressure coating equipment
High temperatures normally necessary for drying coatings can impair very thin substrate films. An alternative drying and curing process is therefore employed in atmoFlex. This new process uses electron beams for curing coatings as well as for surface treatment. The electron beams are even able to penetrate a protective film applied over top and cure the layers beneath. Processing under clean-room conditions to keep layers free of particulates is therefore not necessary.
The new process line is capable of treating not only plastic films but also is capable of coating other flexible substrates such as metal foil, thin glass, and textiles.
Substrates widths up to 1,250 mm can be processed at speeds of up to 150 m/min. The modular character of the process line also offers sufficient adaptability for integrating future technological advancements and researching new processes. The new plant has recently been fitted with a web cleaning system. Contaminants already present on substrate films can be effectively removed this way.
The recently launched OptiPerm project, funded by the Saxony State Ministry for Economy, Employment, and Transportation (reference 3000651169), will be investigating the interrelationships of individual technologies.
This project will research the fabrication of improved systems of barrier coatings for functional films with PVD layers in combination with varnishes and cured by electron beams, and research on optical properties of the film.
Dr. Steffen Günther, group manager responsible for the research at Fraunhofer FEP, said, "atmoFlex considerably broadens the spectrum of our services. It will enable fragile and extremely thin vacuum-deposited layers to be protected by coatings applied directly at normal atmospheric pressure, for example. These types of combined layers are even reliable enough for outdoor use."