Amine-Functional Curatives for Low Temperature Cure Epoxy Coatings

By D.J. Weinmann, K. Dangayach, C. Smith

An active area of technology development is the design of improved epoxy/amine binder systems for low temperature cure coatings. Low temperature cure epoxy coatings allow applicators to ex-tend the painting season because coatings can be applied even when the temperature falls below 50°F. This paper begins with a basic overview of the curing agent technologies available for low temperature epoxy/amine coatings.

The coatings performance of several low temperature curatives with standard liquid epoxy resin is studied in this work. Differential scanning calorimetry is used to monitor the binder systems’ cure rate at 40°F over a 14-day period. The coatings performance in clear varnish formulations is presented; cured at standard ambient conditions (77°F, 55%RH) and at sub-ambient, high humidity conditions (50°F, 90% elative humidity and 40°F, 80%relative humidity).

This study concludes with evaluation of a new approach to low temperature cure epoxy coatings. This approach uses low temperature curatives in combination with polyacrylated epoxy resins. The results show that these new binder systems give improved clarity, blush resistance, and cure development under low temperature, high humidity conditions.