Epoxy Coatings Curing Agent MTHPA 99% Purity Light Yellow Liquid Hardener Methyltetrahydrophthalic anhydride (MTHPA) is a chemical compound belonging to the family of cyclic anhydrides. It is primarily used as an epoxy curing agent, converting liquid epoxy resin into a solid, durable and thermoset material. Product Details Appearance: Light Yellow Transparent Liquid, No Mechanical Impurities Viscosity (mPa.s, 25°C): 40 Max Freezing Point (°C): 0 Max Anhydride Content (%): 41