Viscoelastic behaviour of powder coatings cured at low temperature

 
The most important mega trend in the powder coating market is the move to lower temperatures to achieve full curing. This change directly affects the main stages in powder coatings film formation: melting, flow, gel point and cure completion. These stages determine both the final paint aesthetic and protective properties. In this study, rheological measurements have been utilised to determine the different phases taking place during the film formation process of powder coatings cured at low temperature. The use of dynamic viscosity/time (temperature) cure curves is a powerful technique to quantify formulation and resin parameters. The final aim is to identify the effect of certain resin features on the curing process to enhance resin design. A variety of powder coatings were used in this study to cover the core market offer: HAA and TGIC polyester and hybrid epoxy-polyester systems.