Dry decoating of resilient floorings with non-thermal atmospheric pressure plasmas
IGF 18035 BG
The coating applied on the surface of elastic floorings currently is based on polymers which reduce adhesion of soils and make cleaning much easier. Especially for areas of heavy use, basic cleaning is necessary on a regular basis, where the old coating has to be removed completely and a new coating is applied to obtain optically perfect flooring appearance again. Basic cleaning usually is achieved by use of large amounts of water and chemicals, which results in high water and chemical consumption values, high labor costs and long drying duration.
Therefore, currently a research project is carried out by wfk-Cleaning Technology Institute in Krefeld in collaboration with Forschungsinstitut für Leder und Kunststoffbahnen in Freiberg to overcome these disadvantages. In the frame of the project, a cleaning process to perform basic cleaning of elastic floorings by means of atmospheric-pressure plasma is developed. The process needs no water and chemicals for cleaning and consequently no long drying duration between basic cleaning and re-coating is necessary. Finally, the new process leads to increased area performance and additionally the floorings are usable shortly after basic cleaning process.
During the first working package of the research project, new coatings were developed, that are suitable for application of atmospheric-pressure plasmas. One the one hand, the properties of these coatings have to be adjusted in a way, that sufficient adhesion to the elastic flooring is achieved. On the other hand, the coating should be easily removed by plasma treatment. This is reached by development of a two layer coating.
The bottom layer contains small homogeneously distributed particles, so called “intumescence particles”, which are small liquid filled hollow spheres. During plasma treatment, the liquid inside the hollow spheres evaporates and the spheres expand strongly. This leads to breaking or “blasting” of the complete coating because of extensive reduction of the adhesion to the flooring.
To improve the “blasting” of the bottom layer, the upper layer of the new coating is modified to allow very good heat conduction to the lower layer. Consequently, the heat flow – generated by plasma – is conducted through the upper into the lower layer. Consequently, the desired interaction between plasma heat and intumescence particles is optimized.
At wfk-institute, coatings modified with intumescence media were developed which are suitable for use of atmospheric- pressure plasma.
The results show, that efficient, complete de-coating can be achieved without visible damage to various flooring materials (rubber, PVC, linoleum) by optimum settings of the plasma system. Furthermore, it was shown that even after repeated application and removal of the coating, the desired effect is achieved.
In addition, the behavior of the new resp. modified coating on various elastic floorings is investigated. This includes the examination of properties like adhesion, gloss or transparency of the modified coating. Results show that gloss and transparency of the modified coating are comparable to commercial available coatings. Currently, the adhesion force of the modified coating is optimized.
Parallel to the ongoing optimization of the adhesion of the modified coating, a concept for a mobile plasma cleaning device for de-coating of the modified coating is developed. The results are used for development of an experimental model for plasma based dry basic cleaning.
The research report is available on request from FRT.