UV and Visible Curing of Powder Coatings Based on Unsaturated Polyesters with Allylic Binders

Powder coatings are very attractive, environmentally friendly alternatives to liquid finishes since they are VOC-free. Resins that cure under UV light have already been developed for applications in powder coatings. Most studies deal with acrylic materials or unsaturated polyesters for free radical mechanism and epoxy materials for cationic mechanism.
Fumaric and/or maleic unsaturations lead to a crosslinking reaction in the presence of electronrich double bonds like vinyl ether through a charge-transfer and radical mechanism. these systems (maleate or maleic-anhydride/vinyl ether) are used in UV Curable powder New polymers which can be used in UV and visible cured powder coatings were developed, i.e. unsaturated polyesters terminated with allylic monomers. New light curable powders using these not conventional crosslinking system based on maleic/fumaric unsaturations and allyl ethers were developed. Allyl ethers are cheaper than vinyl ethers, available in a wide variety of functionalities and structures. By using allyl ethers, the properties of the coatings can be tuned and adapted to a large variety of applications.