Process for preparing a water-based (waterborne) coating composition, and water-based coating composition

摘要

An environmentally friendly method is described of coating articles using a water-based coating composition which contains a liquid epoxy resin which is emulsifiable in water, a curing agent for said resin and, if desired, other conventional additives, the epoxy resin and the curing agent being introduced separately into an aqueous system with a viscosity of from approximately 25 to 100 poise and the two systems being mixed. The mixture is then diluted with an aqueous component C to achieve a spray viscosity of approximately 14 to 30 seconds, determined in a DIN 4 mm cup (DIN 53211). The finished coating composition contains a special anticorrosion system in a quantity of from approximately 5 to 25% by weight and a liquid, external plasticiser in a quantity of from approximately 0.1 to 5% by weight. This additive system has a favourable effect on the overall properties of the coated articles, such as the appearance, hardness, adhesion strength, water resistance, protection against corrosion and resistance to chemicals.