High Performance Waterborne Coatings Based on Dispersions of a Solid Epoxy Resin and an Amine-Functional Curing Agent

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A novel, waterborne epoxy system comprised of non-ionic stabilized dispersions of a solid epoxy resin and an amine curing agent has been designed for ambient-cure coatings. The performance characteristics of coatings formulated from the new system have been compared to a standard system.

The new system produced formulated coatings with robust performance over a wide range of amine-to-epoxy stoichiometries (65 to 130%). At 100% stoichiometry, the new system was found to have lower VOC, faster hardness development, better gloss, and higher impact resistance than the standard system. The new formulations also exhibited superior water and salt spray resistance, and a definitive viscosity rise at the end of potlife.

Unlike the standard system, coating morphology of the new waterborne system was found to be similar to a solvent-based coating. For the new system, good coalescing solvents, as judged by gloss and gloss potlife, were found to have low solubility parameters and high boiling points.