Toluene Diisocyanate 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. TDI 80-20 is a mixture blend of 80% 2,4-toluene diisocyanate and 20% 2,6-toluene diisocyanate. The clear to pale yellow liquid organic compound is toxic, has a sharp odor, and is highly reactive. Applications: It is used in the manufacture of polyurethane flexible foam (slab/molding) and non-foam urethanes. Packaging: 250kg Steel drums.