Experimental investigation of the drying process of automotive base paints

To achieve a better understanding of the heat and mass transfer phenomena in automotive base paints during drying, laboratory scale experiments are carried out. The convective drying of one and two subsequently coated paint layers on steel substrates were examined in an air flow parallel to the sample surface. The evaporation of organic solvents and water is examined by gravimetric and gas-phase FTIR measurements. During the drying process the temperature of the sample is recorded. Experiments are conducted at different humidity (2 g/kgdry air–22 g/kgdry air), air temperature (20 °C–80 °C) and air velocity (0.5 m/s–2 m/s). A metallic industrial paint and a simplified model paint are used in the experiments. The variation of the drying climate shows an influence on the composition of the paint during and at the end of the drying process. This might influence the final coating’s quality.