Polyurethane foam products are mainly synthesized from polyether, isocyanate, blowing agent, catalyst, etc. The main process of foam formation is generally considered as follows: 1. Foam is generated in the polyurethane reaction system by physical and chemical methods, and the foam is evenly dispersed in the reaction system. The main foaming method is to use water and isocyanate to produce carbon dioxide. Bubble. 2. The foam generation process requires the viscosity of the reaction system to increase in order to stabilize the foam from escaping. 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-linking system to stabilize the foam and shape it into a product.
In this case, we need at least two catalysts to adjust the reaction. One catalyst is to promote the reaction of isocyanate and water, that is, to promote the foaming reaction. Usually, an amine catalyst is selected; The first is the need to promote the reaction between isocyanate and polyether or alcohol, that is, the reaction of polyurethane molecular chain growth and crosslinking, and metal catalysts are generally used. Therefore, in the synthesis of polyurethane foam, we generally use amine catalysts and organometallic catalysts in combination to produce synergistic effects to achieve the best results. The types and ratios of the specific amine catalysts and organometallic catalysts need to be adjusted and selected according to different products through experiments or experience, so I will not make too many statements here.
