Unsaturated polyester powder coatings with improved surface cure

摘要

Low temperature curable unsaturated polyester powder coatings suited for heat sensitive substrates with improved surface cure through incorporation of active hydrogen groups into the unsaturated polyester molecule. The unsaturated polyesters containing active hydrogens are derived from ethylenically unsaturated polyfunctional carboxylic acids and active hydrogen containing polyols. Full cure on the surface is obtained without the need for polyethylene waxes or oxygen-reactive curative resins that are commonly employed in order to prevent atmospheric oxygen from inhibiting the free-radical induced cure at the surface of the coating.