Coating under atmospheric and vacuum conditions – an innovative combination
Thursday, 5 March 2015
Fraunhofer FEP expands its pilot plant park by a coating plant, which uses electron beams under vacuum conditions for the crosslinking of varnishes and surface treatment.
In vacuum processes extremely thin functional layers are applied to surfaces. Mobile phones, computer monitors or the golden coffee packaging would be unthinkable without them. However, these layers are very sensitive due to their low thickness. A new research area, which was established at the Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology, examines this aspect among other things.
Replacing high temperatures
The scientists of Fraunhofer FEP see enormous potential in the combination of coatings produced by means of vacuum and atmospheric pressure processes. The sensitive vacuum coatings can be protected by thicker coating layers. The innovative idea is that high temperatures, which usually occur during varnish drying, will be replaced by alternative drying and cross-linking procedures. Therefore, Fraunhofer FEP relies on a new roll-to-roll plant for flexible substrates (plastic or metal film, thin glass), which uses electron beams under vacuum conditions for the crosslinking of varnishes and for surface treatment – the atmoFlex.
Dr. Steffen Günther, project manager, describes the advantages of the new plant concept: "The plant, which was designed specifically according to our requirements, will provide an electron beam system and the possibility for touchless slot-die-coating. The processing of substrates, which have already been vacuum-coated, will be considered specifically by this touchless varnish application process. The mechanical stress on the substrates will be minimized within the track due to the fact that all deflecting rollers are designed larger than in comparable plants. Beside the use of smoothing or stamping films will be possible due to special modifications in the track control concept. Thus extremely smooth surfaces or decorative films for furniture can be produced.”
Encapsulation of sensitive electronic components
The company 3D-Micromac is currently developing the atmoFlex, which shall be put in operation at Fraunhofer FEP in 2015. The plant will be able to process substrates up to a width of 1250 mm and will offer a processing speed of up to 150 meters per minute. The modular construction of the plant will provide various possibilities to integrate technological add-ons and to investigate new processes in the future.
The scientists are looking forward to the new plant, which allows to make processes more efficient in order to provide a competitive advantage to their customers in the future. Fraunhofer FEP addresses various application fields with this new approach. On the one hand, the objective for durable and defect-free encapsulation of sensitive electronic components like OLED, organic and inorganic solar cells (CIGS, DSSC) will be pursued. On the other hand, innovatively structured layers will be realised, which will be used for high-value packaging. Further, layer developments for outdoor products will play a major role. The possibility for the modification of materials by electron beam irradiation will initiate new comprehensive developments.