Curing agent, also known as hardener, curing agent or fixing agent, is a kind of substance or mixture that promotes or controls curing reaction. Resin curing is a process of irreversible change of thermosetting resin through condensation, closed-loop, addition or catalysis. Curing is accomplished by adding curing agent. Curing agent is an indispensable additive, whether as the binders, coatings and castables, otherwise epoxy resin can not be cured. Varieties of curing agents have great influence on the mechanical properties, heat resistance, water resistance and corrosion resistance of the cured products.

Curing agents are classified according to chemical composition

1. Aliphatic amines such as vinyltriamine DETA, aminoethyl piperazine AE
2. Aromatic amines such as m-PDA MPD diaminodiphenylmethane DDM HT-972 DEH-50
3. Amide Amines
4. Latent curable amines
5. Urea substitutes.