New organic yellow pigments with high fastness to light and weathering Part 1 Available to Purchase

Until recently only few organic yellow pigments with a sufficiently high standard of fastness —in particular fastness to light and weathering— were available for the manufacture of quality paints for outdoor use. In this article four new organic yellow pigments of high fastness are introduced. In a trial series these products were tested side by side with well‐established yellow pigments for their fastness to weathering in a stoving paint. For this purpose they were exposed to weathering in Florida for one year. The fastness to weathering was evaluated not only visually by the most widely used method, viz. comparison with the 5‐step Grey Scale, but also colorimetrically by determination of a ▵ AN value as a measure of any shade change which might have occurred. The values thus obtained are represented in various ways and compared with one another. Moreover, the fastness to weathering of the new and the old yellow pigments is compared with that of selected pigments of different shades which are also used for paints for outdoor use.