Improvement of the Light Stability of Automotive Water Borne Coatings: a Difficult Task

Abstract

One of the most important current challenges for paint manufacturers is the reduction of volatile organic compounds （ VOC ） in their formulations. As a potential compliant technology for VOC reduction, water borne clear coats are predicted to develop strongly over the coming years. It must be stated that any impairment of the light stabilising performance of these water borne clear coats is unacceptable in the automotive industry. Due to the lack of techniques for the effective and homogeneous incorporation of light stabilisers, which are in general hydrophobic substances, into water borne clear coats, new product forms addressing this issue have become mandatory. Progress has been made with the development of water compatible product forms of water insoluble hydrophobic additives by using a Novel Encapsulated Additives Technology （ NEAT ） micro encapsulation techniques. NEAT enables the development of water borne clear coats for automotive application that show the same performance level as current state of the art solvent borne systems. By this novel encapsulation technology, the best UVA’s and HALS are made available for use in aqueous systems. The easy incorporation of the NEAT light stabilizers requires no need for co-solvents. NEAT light stabilizers offer a permanent protection due to a high wash-out resistance and they do not show a negative influence on transparency and gloss.