100% Solid Epoxy Hardener MTHPA 99% Purity Methyltetrahydrophthalic Liquid 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 Specifications AppearanceLight Yellow Transparent Liquid, No Mechanical Impurities Viscosity (mPa.s, 25 °C)40 Max Freezing Point (°C)0 Max Anhydride Content (%)41