The Study of Cure Mechanism of a Fusion-bonded Epoxy Powder Coating

The degree of cure (DOC) of a new type of epoxy/dicyandiamide powder coatings was detected by using solvent extraction on the free film cured at temperatures from 160℃to 230℃ for different time and the kinetic process was analyzed. The results revealed that the cure reaction yielded a single Arrhenius activation energy (91.4kJ/mol), which indicated that there might be only one overall reaction mechanism in the range of the temperature tested. The cure reaction of epoxy/dicyandiamide powder system was complex, involving two principal reactions between epoxide and amine hydrogen, and between hydroxyl groups and —CN. The cure mechanism was also discussed.