Recent Advances in High Solids Coating Technologies

Abstract

Recently, high solids coatings are widely used in the industrial coatings fields, especially in automobile coating field, in the United States. In Japan, the use of high solids coationgs has been gradually increasing.
Since the melamine cured high solids coatings usually consist of the oligomeric polyol resin, low molecular weight melamine resin and sulfonic acid catalyst, it is very important to elucidate the influences of molecular weight of oligomer and curing mechanisms on the film appearance, such as sagging and the orientation of aluminum pigment, and also on the film properties.
In this paper, recent works on the developments of the raw materials for high solids coatings including acrylic oligomers, polyester oligomers and rheology control agents were reviewed. Then the recent works on the basic problems of high solids coatings, such as rheological properties of oligomer solution, prediction of solution viscosity, viscosity behavior during thermal curing, reaction mechanisms of hexamethoxymethylmelamine, mechanical properties and weathering properties of cured films were reviewed.