TDI 80-20 is a toxic and highly reactive organic compound. The chemical formula for TDI is CH3C6H3(NCO)2. TDI is often marketed as TDI 80/20. Commercial production of toluene diisocyanate involves the conversion of toluene to a diamine, which is reacted with phosgene to yield TDI, a clear to pale yellow liquid with a sharp odor. TCC’s TDI 80-20 is a mixture blend of 80% 2,4-toluene diisocyanate and 20% 2,6-toluene diisocyanate.