Polyurethanes are generally made by reacting a diisocyanate, such as toluene diisocyanate (TDI) or methylene diphenyl diisocyanate (MDI), and a blended polyol. When a polyurethane foam is desired, the process uses additional chemicals, such as amine and/or metallic salt catalysts, auxiliary blowing agents, and silicone surfactants, to achieve the desired properties.
Amine catalysts are used to control and/or balance both the gelling reaction and the gas-forming or foaming reaction responsible for foam formation. Although several organometallic compounds or salts may be used as catalysts in the production of polyurethanes, many polyurethane manufacturers use either tertiary aliphatic amines or alkanolamines. Amine catalysts are typically 0.1 to 5.0 percent of a polyurethane formulation.