Effect of Coating Composition on UV-Curable Powder Coatings
UV-curable powder coatings are attractive due to the combination of properties of powder coatings and UV curing. This attractiveness can be expressed in being environmentally friendly, and having the ability for spray application, powder recycling, and relatively fast cure compared to conventional powder coatings.
Like conventional powder coatings, the UV powder coating formulation is processed by extrusion. Due to the semi-crystalline nature the extrusion temperature may not exceed 70 deg C, and the extrudate temperature may not be higher than 75 deg C. This temperature is above the glass transition temperature, but below the melting range of the crystalline regions. Above the melting temperature the melting of the crystalline regions leads to a dramatic reduction in viscosity, which makes extrusion virtually impossible.