Bright Prospects for Durable Paintwork

Lab assistant Stefanie Werkstätter compares the two panels: even after 1000 hours, the brilliant colors of the sample formulated with the new PRIMIS® AF 1000 dispersion (right) remain unchanged, whereas the commercial alternative (left) exhibits considerable weathering.

Pigments are blended into exterior paints and renders in order to add rich, vivid color to the walls of homes and other buildings. While organic pigments are known for their wide variety of shades, they are not particularly stable, especially when exposed to UV radiation. As a result, they fade and become increasingly pale over time due to the sun and weather. Inorganic pigments, by contrast, are better able to resist the elements, but do not offer the same variety of shades and hues.

The new PRIMIS® AF 1000 binder significantly increases the stability of organic pigments in paint formulations. “Mineralization is a more efficient way of protecting organic pigments from UV radiation,” Kotschi notes. As the WACKER chemist then goes on to explain, “They lose their brilliance and intensity much more slowly as a consequence, allowing exterior paints to retain their original shade longer.” This enhanced color consistency and paint longevity has also been verified in the lab using what is known as a QUV tester to simulate accelerated weathering. In these experiments, lab employees exposed the test materials to alternating cycles of UV light and moisture at high and low temperatures, thereby mimicking the effects of sunlight, dew, rain and spray. Scientists can simulate within a few days or weeks the damage caused by months of exposure to climate and weather.

Focusing on Four Pigments

The laboratory experts tested exterior paints containing the new PRIMIS® AF 1000 dispersion over a period of 1,000 hours and compared the results to those obtained using standard commercial alternatives based on vinyl acetate-ethylene and styrene-acrylate. The tests focused on four particularly critical organic pigments that produce attractive colors in the final formulation, but that, unfortunately, readily fade or bleach out.

Lab test results showed that the new PRIMIS® AF 1000 binder does a particularly good job of stabilizing the pigments for long periods of time. “Paints and renders formulated with new PRIMIS® AF 1000 provide optimum protection from wind and weather, and maintain brilliant colors – both for new buildings and renovated structures,” explains Dr. Markus Busold, global market manager for Coatings at WACKER POLYMERS.