Polyurethane catalyst (foam) The most commonly used ones are tertiary amines, quaternary amines, amine salts and metal carboxylates acid salt (such as Sn2+, Sn4+, or K+). Tertiary amines show high selectivity for foaming reactions and also influence gelation and cross-linking reactions. Amine salts and heat-sensitive amines, such as salts of triethylenediamine, are primarily used to provide delayed reactions.
The reaction selectivity of the foam system is measured by the storage time of the system, the shape of the product, and the demoulding time. The selectivity of the catalyst affects the reaction equilibrium, the type and sequence of formation of polymers with different linkage methods, and the fluidity of the foam system. Catalysts also affect the physical properties of the final resulting foam.
Polyurethane foams are available in a wide variety of polymer structures and, therefore, address a wide range of commercial needs. Polyurethane catalyst The choice of type profoundly affects the gelation and foaming reactions of the foam. The choice of catalyst affects the overall reaction of the foam system, as well as the selectivity for a specific reaction.
Amine catalysts mainly affect the reaction between water and isocyanate. They are often called foaming catalysts. However, they have varying degrees of activity and promote reactions between polyols and isocyanates. This property of amine catalysts is unique for polyols with high inherent reactivity. In some formulations, only amine catalysts are used. There are also some ultra-concentrated amine-free catalysts, such as some antimony compounds, that can be used as foaming catalysts.
Tin compounds are a type of catalyst used to promote the reaction between polyols and isocyanates. Therefore, they are known as gel catalysts. As with amine catalysts, some formulations use only organotin catalysts. Metal carboxylates have strong gel reactions.
