Multifunctional UVEB Curable Oligomers for Optical Coatings
Hard, optical clear, protective UV curable top coats are necessary for a variety of demanding applications in the automotive, aviation, electronics and scientific instrumentation markets. Coatings with special properties, such as anti-fog, conductivity, anti-Newton ring, anti-glare performance, are highly sought-after products. However, due to limited choices of oligomers, current coatings cannot easily meet customers’ varied demands. Oligomers with low functionality may hardly meet scratch (mar) resistance or hardness specifications. Some coatings can only be applied as very thin films due to brittleness. Furthermore, chemical resistance, anti-fog, anti-static and anti-glare properties all require artful formulation choices between monomers, oligomers, additives, photo-initiators and diluents. Lack of functionalized oligomers often restrict the creative venues for multipurpose applications. New oligomers have been developed that can solve problems like these. This presentation will discuss new polyurethane acrylate oligomers being developed using grafting and block copolymerization that, under adequate formulation, provide excellent optical properties while presenting great toughness after UV curing. Raw materials with different characteristics of hydrophilicity, hydrophobicity, conductivity, elasticity, mechanical properties, and/or formulation compatibility are selected in obtaining oligomers of desired properties. Oligomers targeting for anti-fog applications, glass adhesion, and soft touch application, will be discussed. Specifically, anti-fog coatings for Polycarbonate (PC) substrate has been evaluated extensively for performance against many real life use conditions. Some formulations were compared against other commercial products in the market place.