Method for reprocessing and recycling of aqueous rinsing liquids from car painting with water-based paints in automobile industry

In the paint processes of modern car plants the paint to be applied on the car bodies change after every few numbers. In order to avoid intermixtures of different lacquers the application systems has to be cleaned before every change by means of a rinsing liquid. Water based lacquers require water based cleaning agents. For these rinsing waters a new recycling process based on an evaporation process, a fractionated condensation and an after treatment of the condensates is described. The compatibility of the recycled system for lacquers is investigated. After a test with ten recycling loops no accumulation of harmful substances occurs. In comparison to original agents the recycled rinsing liquids show comparable or better cleaning abilities. The comparison of the energy consumption and the disposal of CO₂ and of volatile organic compounds between the application of fresh rinsing liquid with disposal after usage and recycled rinsing liquid show major advantages of the recycling process.