Selection of polyurethane foam catalyst

Polyurethane foam products are mainly synthesized by polyether, isocyanate, blowing agent, catalyst, etc. The main process of foam formation is generally considered as follows:

        1. Use physical and chemical methods to produce foam in the polyurethane reaction system, and make the foam uniformly dispersed in the reaction system. The main foaming method is to use water and isocyanate to produce carbon dioxide for foaming.
 
        2. The foam generation process requires that the viscosity of the reaction system increase to stabilize the foam from being escaped.

        3. When the foam formation reaches the required number and size, the viscosity of the reaction system needs to continue to increase or even form a cross-linked system to stabilize the foam and shape it into a product.

        In this case, we need at least two catalysts to adjust the progress of the reaction. One catalyst is to promote the reaction of isocyanate and water, that is, to promote the foaming reaction. Usually, amine catalysts are selected; the other is required To promote the reaction of isocyanate and polyether or alcohol, that is, the reaction of polyurethane molecular chain growth and crosslinking, metal catalysts are generally used. Therefore, in the synthesis process of polyurethane foam, we generally choose amine catalysts and organometallic catalysts to cooperate in order to produce a synergistic effect to achieve the best effect. The types and proportions of specific amine catalysts and organometallic catalysts need to be adjusted and selected according to different products by experiment or experience.