Methyl tetrahydrophthalic anhydride, also known as methyl tetrahydrophthalic anhydride, referred to as MeTHPA, there are two isomers, namely 4-methyl tetrahydrophthalic anhydride and 3-methyl tetrahydrophthalic anhydride, melting point is 65℃ and 63℃, rarely used as a curing agent alone. The actual commodity is a liquid mixture of multiple isomers. Molecular weight 166.17. Light yellow transparent oily liquid, relative density 1.20 ~ 1.22. Freezing point < 20 ℃. Boiling point 115~155℃. Viscosity (25℃)40 ~ 80mPa·s. Refractive index 1.4960 ~ 1.4980. Anhydride content ≥40%. Neutralization equivalent of 81 to 85. Flash point 137 ~ 150℃. Soluble in acetone, ethanol, toluene, etc. Good stability in the air i not easy to precipitate crystallization. Low toxicity LD502102mg/kg.