There are many types of hardeners in epoxy resin adhesives, usually it is classified according to the following methods.
① according to the different chemical structure can be divided into alkaline and acidic curing agent two types. Alkaline curing agents include fatty amines, aromatic amines, modified amines and other nitrogen-containing compounds such as imidazoles and dicyandiamide. Acidic curing agents such as organic acids, anhydrides and boron trifluoride.
② According to the different curing mechanism of epoxy resin is divided into curing agent reaction and curing agent catalytic type (latent type) two categories. Primary amines, low molecular polyamides, organic acids and anhydrides are reactive curing agents, imidazoles, dicyandiamide and boron trifluoride are catalytic curing agent.
③ According to the different curing temperature can be divided into room temperature, medium temperature and high temperature hardeners.