Hydrophobic UV-Curable Powder Clear Coatings: Study on the Synthesis of New Crosslinking Agents Based on Raw Materials Derived from Renewable Sources

Abstract

Methods for the synthesis of urethane acrylates used as new crosslinking agents for hydrophobic UV-curable powder clear coatings were developed. In the synthesis of urethane acrylates, isophorone diisocyanate, glycerin, xylitol, polyethylene glycol and polysiloxane KF-6000, as well as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate, were used. In order to increase the functionality of urethane acrylates, glycerin and xylitol derived from renewable sources were introduced. The chemical structure of the urethane acrylates was verified by IR spectroscopy. UV-curable powder clear coatings were obtained through a combination of urethane acrylates with unsaturated polyester resins. The thermal behavior and crosslinking density were examined using DMA. The obtained coatings were evaluated by performing the following tests: roughness, gloss, scratch resistance, hardness, adhesion to steel and water contact angle. As part of this research, high hydrophobicity and scratch resistance of UV-curable powder clear coatings were developed, which are a VOC-free and economically attractive alternative method for low thermal resistance surface protection, such as for composites, wood and wood-based materials.

Keywords

• UV-curable powder coatings
• crosslinking agent
• urethane acrylates
• xylitol
• DMA