TDI : Basics

Toluene Di-Isocyanate: it is an aromatic compound having two Isocyanate functions on a toluene molecule.

Two isomers of TDI are used in the production of Polyurethane Foam: 2, 4 – TDI & 2, 6 – TDI. The difference between those two isomers is the position of the Isocyanate function on the carbon atom of the aromatic cycle.

TDI counts up to 34.1% of the Isocyanate market. In general both isomers are marketed in as a mixture 80 / 20 or 65 / 35. TDI 80 / 20 could be sometime referred to TDI – 80 or simply T-80 (This has nothing to do with the Russian Tank T -80 U ;)

TDI is a colorless liquid with low viscosity; however, if exposed to air for a period of time it can turn to pale yellow color. Density is about 1200 kg per cu.m.

Due to the fact that TDI has a relative high vapor pressure, it seems to be very irritating to handle with it without using proper safety measures.