Isocyanate-Free Michael Addition Cured Aliphatic Topcoats

By M. Gessner, A. Nanda, R. Subramanian, D. Sauer, W. DeGooyer, E. McCracken, L. Lindsey,, F.G.H. van Wijk

In 2015, the breakthrough of a novel blocked catalyst and kinetic control additive package used in conjunction with Michael Addition chemistry was announced at the European Coating Conference.¹ Prototype paint formulae highlight the very fast drying 2K system (<15 min, ambient) and the unique decoupling of dry time and pot life (>5 h), expected to trigger new paint and process solutions.

The fast-cure system was designed as a topcoat over epoxy primers for use in the industrial market. The advantages of fast cure, long pot life, and low- to no-baking were described at other conferences since the introduction. However, most factory-applied systems do not fully make use of these advantages. Air-dry-only applications fully use the advantages of this new technology. Furthermore, the base-catalyzed system is a natural consideration for use over alkaline surfaces such as concrete. Very low-VOC/air-dried coatings can be made using reactive diluents, which can reduce paint viscosity, but also greatly increase the crosslink density. There are also available low-viscosity crosslinkers, which reduce the viscosity of the paint, yield good paint properties, and have excellent appearance.

This article shows the low-VOC potential while the fast-dry nature allows fast return-to-service for flooring and other applications.