Waterborne acrylic-epoxy coatings

Waterborne two-component acrylic-epoxy coatings are gaining popularity as topcoats in moderate duty industrial and high performance architectural (HIPAC) applications. This increased popularity is due to their attractive handling, application, and performance properties, along with their low solvent content and odor. The objectives of this work were to characterize the cure and property development of these coatings, evaluate performance properties of cured films, and investigate a new epoxy resin dispersion in existing acrylic-epoxy formulations. These evaluations confirmed that existing acrylicepoxy coatings have long pot life and short dry times while displaying a range of chemical resistance and physical properties. IR spectroscopy and differential scanning calorimetry (DSC) results indicated that the extent of cure at ambient conditions over a 21-day period was minimal; however, dynamic mechanical analysis (DMA) and solvent swell results did illustrate noticeable crosslink density development under these conditions. DSC results demonstrated more complete reaction and cure after heating. Direct substitution of a novel epoxy resin dispersion into these formulas resulted in lower required solvent content, shorter dry time, higher gloss, higher crosslink density, and improved water and scrub resistance.