Water-based coatings are environmentally compatible but they have one drawback—microorganisms such as bacteria can reproduce in the water and paints used and then adversely affect the quality of surface coating. Typically, biocides have been used to control these bacteria.
Now, a sterilization process for industrial water and paints that uses electric impulses is being developed to address this issue. The program is funded by the German Federal Ministry of Education and Research and coordinated by researchers at Karlsruhe Institute of Technology (Karlsruhe, Germany).
The new electric impulse technology, which focuses on both surface treatment for the automotive industry (cathodic immersion painting) and applications for general industry (coating of industrial goods by anodic immersion painting), works without chemical additives, reduces water consumption, and contributes to water protection
By means of electric impulses, cells or microorganisms are exposed to an electric field. The cell membrane is polarized, which means that electric poles form and aqueous pores open. This eventually results in the death of the microorganisms. As the electric impulses impart a purely physical effect, bacteria are not expected to develop resistances, as they do in the case of biocides.
In the automotive industry, painting the vehicle body consumes the highest amount of water (up to 600 L per car body). For this reason, the electric impulse technology is being integrated into a new, automated, resource-efficient water management and plant concept for pretreatment and immersion painting that will optimize the water cycle at the factory and reduce freshwater consumption.
Source: Karlsruhe Institute of Technology, www.kit.edu.