Transfer project T06 within SFB-TR 87

Low-maintenance continuous Air2Air PECVD film coating by In-Plasma concept

In food packaging, plastics provide protection against germs or mechanical influences and thus make an important contribution to preventing food waste. However, the plastics used for this purpose, such as polyethylene terephthalate (PET), do not have sufficient barrier properties against gases and flavorings for certain applications, so they have to be equipped with an additional barrier. One way of providing plastics with a barrier without impairing their recyclability is plasma enhanced chemical vapor deposition (PECVD). This is a vacuum-based coating process in which optically transparent coatings with a thickness of just a few tens of nanometers and high barrier efficiency (often SiOx coatings) are polymerized on a substrate with the aid of a plasma. Compared to the already industrially established use of this method for the coating of PET bottles, PECVD for the coating of film webs is not yet widespread because the currently available technology only allows a discontinuous (batch-wise) process so far and continuous coating processes could not yet be implemented economically. One goal of this transfer project is to overcome the challenges of such continuous processes, such as low layer deposition rates or particle entrainment and dust formation in the reactor, and to make PECVD for coating films in-line capable, low-maintenance and suitable for mass production. This will make recyclable material solutions more attractive for the packaging industry and strengthen the circular economy in Germany.

In this transfer project, the plant concept presented will be implemented and a laboratory reactor set up. Subsequently, the plant system will be evaluated with regard to operational safety and necessary cleaning cycles, and the scalability of the system will be investigated. Spectroscopy and probe-based plasma diagnostic methods will be used to monitor the plasma properties and establish a control system for the process. The broad consortium of industrial partners covers the entire spectrum of the industries involved, providing the project with strong practical expertise.