Scratches on plastic surfaces are an everyday occurrence, are annoying and often devalue what is frequently a high-quality object. Lasting protection against mechanical erosion and retention of the decorative appearance are, therefore, vitally important. Prime candidates to achieve these qualities are transparent, high-gloss, solventborne, two-pack PUR coating systems for plastic substrates, which require scratch resistance. Such coating systems play an important role in meeting the demand for lasting quality, since high-gloss finishes (piano lacquer effect) are increasingly present in our daily lives. Components for automotive interiors, LCD televisions, tablet computers and smart phones are just a few of the products whose appearance has changed from matte to high gloss in recent years.
This article presents innovative nanosilica particle technology based on a modified sol-gel process. The product, NANOPOL® C 784 from Evonik Industries AG, is a pure, solvent-based 50% w/w nanosilica composite for two-pack PUR coatings. The advantage of this technology is that the products are easy to handle, can be straightforwardly incorporated into a polyol matrix and can be used in a wide range of applications. This new nanosilica particle technology can thus be used in conjunction with common binders to develop high-gloss, two-pack PUR clearcoats with greatly increased abrasion resistance.