The use of gypsum as an additive in waterborne base coats for automotive coating

Abstract

The Automobile industry focuses interest in waterborne base coat lately due to low production output, long flash off time and adhesion before curing. Efforts are been made in researching for base coat formulation to ensure reduction of flash off time while maintaining and improving their properties. The paper investigates the effect of gypsum in waterborne base coats for automotive coating, formulation, preparation and drying of the waterborne base coat samples at various temperatures. The samples of deposited coat were weighed and analysed in Minitab software using Taguchi design. The waterborne base coat was observed when sprayed, having no splashing and droplet on the sample surface. The gypsum facilitated the evaporation of moisture from the film in a shorter time at low temperature of 50˚C which is called the flash off time before curing with clear coat. The flash off time of 7-8minutes was determined at 50˚C for the formulation. Adhesion test was carried out on the films and good adhesion between the primer, base coat and clear coat were achieved. Drying at 50˚C helps in the reduction of energy consumption in the automobile industry.