Amine: Basic

Amine is commonly used in manufacturing flexible foam.

Amine accelerates the blowing reaction between water and TDI as well as to a lesser extent, the gelling reaction between TDI and Polyol.

For this reason, some foam manufactures use combinations of various amine types in the attempt to balance the gelling and blowing reaction. This helps in some ways to control the foaming process.

Out of the three types of amine that exist, only tertiary amines are used as catalyst in the foaming process.

Primary and secondary amines have free hydrogen atoms that will react very fast with TDI. However, tertiary amine has no free hydrogen atom so that it serves (by the free electron pair on the nitrogen atom) as a catalyst rather than as a reagent.