UV and Visible Curing and Properties of Powder Coatings based Onallylether, Maleimide and Acrylic Binders

摘要

The curing performance of low temperature curable powder coatings based on mixtures of maleic/fumaric unsaturated polyesters with allylic unsaturated polyesters, malimide and acrylic crosslinker has been investigated. High conversion yields are obtained for all the systems studied. With a suitable PI, the powders can be used under visible light. Moreover, the MI/AE system can be cured without added PI under UV light. The MI/AE powders shows very high mechanical properties and a full curing is obtained with a suitable PI system but also by a post irradiation thermal process in the dark. The versatility of the chemistry of allyl ethers allowed to obtain powders having a very good physical storage stability and showing very good flowing properties. The properties of the cured coatings are very good and can be tuned by changing the allyl ether crosslinker. The curing mechanism in the presence of allyl ethers and oxygen involves a photo-oxidative crosslinking which leads to a post-crosslinking after exposure to light.