Novel Concept for Low Temperature Curing Powder Coatings Based on Hyperbranched Polyesters

By Mats Johansson , Eva Malmström, Andreas Jansson, Anders Hult

The concept of using hyperbranched polymers as scaffolds for solid thermoset resin applications is described. A series of semi-crystalline methacrylate-functional aliphatic poly-esters has been synthesized and characterized for applications as solid thermoset resins, e.g., powder coating resins. The polyester resins have been crosslinked by UV irradiation producing either amorphous or semi-crystalline crosslinked films depending on the initial structure.

The resins are based on hyperbranched aliphatic polyesters onto which crystalline linear aliphatic polyester chains have been grafted and end-capped with meth-acrylate moieties. The resins exhibit a rheological behavior suitable for low temperature curing powder coatings, i.e., films that can be readily formed and UV cured at temperatures below 80°C.