Diisocyanates are a family of chemical building blocks mainly used to make polyurethane products, such as rigid and flexible foams, coatings, adhesives, sealants and elastomers. Many of the products we rely upon every day are safer and more comfortable through the use of polyurethanes made possible by diisocyanates.

Polyurethane chemistry is complex, but the basics are relatively easy to understand. Polyurethanes are produced by combining diisocyanates with polyols and other chemical additives. Because a variety of diisocyanates and a wide range of polyols can be used to produce polyurethane and the speed of the reaction can be adjusted, a broad spectrum of materials can be produced to meet specific application needs. Diisocyanates are important in the production of countless products, particularly in the transportation and construction industries.

There are two primary aromatic diisocyanates: toluene diisocyanate (TDI) and methylenediphenyl diisocyanate (MDI). There are two primary aromatic diisocyanates: toluene diisocyanate (TDI) and methylenediphenyl diisocyanate (MDI).

TDI is used primarily in the production of flexible foams. MDI is used in the production of a variety of polyurethane products like elastomers, sealants, adhesives and coatings.