Glass Transition Temperature of Epoxy Paints

California Materials Expert Discusses The Temperature Performance of Two Part Epoxy Coating:
Most users think that, because epoxies are listed as thermoset plastics, epoxies do not soften at elevated temperatures. Actually, after initial hardening epoxies demonstrate softening at temperatures above the initial cure temperature. This was the case for epoxy paint used to coat the inside of sanitary water holding tanks. The tanks were painted in winter; so, the initial cure was at approximately 55° F. When the weather warmed the surface of the tank reached 115°F, and the epoxy paint was found to be soft and rubbery.However, over time the epoxy paint became hard at the elevated temperature as the higher temperature became the effective curing temperature. The common view is that epoxies are thermoset plastics; however, they can soften under certain conditions