Development of an effective and economical lasercleaning process to remove temporary floor care products
AiF 187 ZBG
One of the basic requirements for the cleaning ability of floorings is the optimisation of surface energy with the aim of minimizing soil adhesion. This often is achieved by applying temporary floor-care products.
These temporary coatings (based on polymers with and without wax) improve the cleaning properties and minimize the abrasion by daily use. This leads to substantially increased durability of the floorings.
After a certain time, however, the temporary films have to be removed by a water based stripper and the filming with a new temporary floor care product has to be carried out. Before new films can be applied, the cleaned flooring has to dry in a sufficient way. This drying time causes a lot of delays in the operational procedure of the cleaning service enterprises.
As a result the economic efficiency of cleaning enterprises is affected. A new method for the removal of temporary floor care products is the application of the laser technology.
The respective investigations were at first carried out with a CO2 laser (100 W power), as the absorbance of commercially available floor care dispersions is quite high (40-70 %) at the wavelength of the CO2 laser radiation (10,64 µm). This facilitates the decoating processes.
An efficient coating removal by means of a CO2 laser is, however, constrained by a very narrow experimental set up.
Even very small changes of laser parameters, layer thickness, floor care dispersion as well as soiling or ageing of the floorings have a negative impact on the decoating efficiency. Treating bigger areas (10 x 40 cm2) demands therefore an extensive adaptation of the laser process conditions.
Good coating removal was obtained at up to 30 % higher laser intensities (till 2100 W/cm2) and up to 30 % lower scan velocities (1.7 bis 2.3 m/s).
Residual thin films comprising soiling traces may be removed efficiently especially from PVC-floorings by means of a mechanical dry after-treatment by a scrubber dryer.
The non self-limiting character of the described laser process is a disadvantage. Consequently local overheating of the floorings due to relatively high laser absorbance may lead to irreversible damages.
Due to the low scan velocities mentioned above, the use of a CO2 laser resulted in a relatively low performance per time unit. Higher values resulted by using a Nd:YAG laser. The results show the feasibility of the laser-based removal of temporary coatings.
There still exists research demand regarding the minimization of the damage of the floorings. An approach for this purpose lies in the integration of a laser-reflective layer into the coatings. Therefore a follow-up proposal on that topic has been submitted to the funding organisation.
We thank the Arbeitsgemeinschaft industrieller Forschungvereinigungen e.V. (AiF) (Association of Industrial Research Organisations) for funding the project AiF 187 ZBG through a financial support by the Federal Ministry of Economic Affairs.
The research report is available on request from FRT.