Convective and radiant (IR) curing of bulk and waterborne epoxy coatings as thin layers. Part II: Infrared curing

In the first part of this paper, a method for studying the curing of 100-mu m-thick epoxy-based layers on steel substrates was described. In this seco nd part, we extend our study to radiative (infrared) heating conditions. A simple waterborne epoxy reactive system based on a diglycidylether of bisph enol-A prepolymer and a polyether triamine was used. The chemical kinetics during infrared heating were studied with the reaction kinetics recorded du ring convective heating. A second order autocatalytic model described the d ata. The curing mode had no significant influence on the heating kinetics b ut the heating rate had a significant influence on the curing kinetics. Hig her heating rates can be achieved by infrared heating conditions compared w ith convective heating. The gelation phenomenon was changed for infrared co nditions. Microdielectrometry can be used to record in situ the extent of r eaction of the epoxy reactive system for thin layers during radiant heating .