These high performance properties are the result of using highly crosslinked polyurethane coatings, which can be derived from high-functional polyester resins (PES) or polyacrylate resins (PAC) and aliphatic polyisocyanates. Typical applications include garage and hanger floors where resistance to brake fluid, Skydrol and tire staining are needed. These performance attributes have also made highly crosslinked polyurethane coatings useful as graffiti-resistant coatings, i.e., coatings that can be cleaned of graffiti paint with aggressive cleaners that will not destroy the original coating on the substrate.1,2 Until now, these highly crosslinked polyurethane coatings have only been available in solvent-based formulations. Significant amounts of solvent classified as VOCs can contribute to air pollution and/or offensive odors.
Waterborne polyurethanes with ultra-low VOCs, specifically designed for concrete floor coating applications, have recently been developed with performance properties approaching solventborne polyurethanes.3 This development has led us to wonder if waterborne polyurethane coatings could be used to function as graffiti-resistant coatings for concrete substrates. Additionally, these 2-component waterborne polyurethane topcoats would allow for graffiti resistance in a matte finish – something that the construction market is looking for.