Q: We use an epoxy in our powder process here in our facility, and it doesn’t pass an accelerated exposure test. Should this kind of powder be able to pass the QUV test? We are having troubles with our customers.
A: Thank you for the question, this is a good one. The QUV test simulates the exposure a coating will experience in a high-intensity UV environment. The wavelengths are close but not identical to the sun. It is a decent comparative test for similar formulations.
Epoxies will not last long in a QUV chamber without fading and chalking. Similarly, a hybrid powder coating that also contains epoxy resin will not resist degradation in the QUV cabinet.
Powder coatings that have good to excellent QUV performance are based on the following chemistries: aliphatic polyurethanes, polyester TGIC, polyester HAA, acrylic, and fluoropolymer.
Pigmentation also has a strong influence on UV resistance. Mixed metal oxides have the best performance.