In the polyurethane industry, catalysts are used to control the rate of the reaction between isocyanates and hydroxyl groups. This reaction is responsible for the formation of polyurethane polymers. The type of catalyst used will depend on the desired properties of the final polyurethane product.

There are many different types of catalysts used in polyurethane production. Some of the most common types include:

Amines: Amines are the most commonly used catalysts in polyurethane production. They efficiently catalyze the reaction between isocyanates and hydroxyl groups. However, amines also lead to the formation of undesired by-products, such as amines and amides.
Organotin compounds: Organotin compounds are also effective in catalyzing the reaction between isocyanates and hydroxyl groups. However, they are more expensive and difficult to handle than amines.
Metal salts: Metal salts, such as zinc chloride, can also be used as polyurethane catalysts. They are less expensive than amines and organotin compounds, but they are not as effective at catalyzing the reaction between isocyanates and hydroxyl groups.
The choice of catalyst depends on many factors, including the type of polyurethane resin used, the desired properties of the final product, and the cost of the catalyst.

Catalysts are an important part of the polyurethane manufacturing process. They help ensure that polyurethane resins are cured properly and that the final product has the desired properties.