Brief Analysis of Three Types of Polyurethane Catalyst Products

Brief Analysis of Three Types of Polyurethane Catalyst Products

Polyurethane products can generally be divided into foam, elastomer and polyurethane resin. The following sections will analyze the selection of polyurethane catalysts for these three types of products.

1、 Selection of Polyurethane foam Catalyst

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

1. Foam is produced in the polyurethane reaction system by physical and chemical methods, and foam is evenly dispersed in the reaction system. The main foaming method is to use water and isocyanate to produce carbon dioxide to foam.

2. The production process of foam requires that the viscosity of the reaction system increases with the increase in order to stabilize the foam from escaping.

3. When the foam formation reaches the required number and size, the reaction system viscosity 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 foaming reaction. Generally, amine catalysts are selected; The other is to promote the reaction of isocyanate with polyether or alcohol, that is, the reaction of polyurethane molecular chain growth and cross-linking. Generally, metal catalysts are used. Therefore, during the synthesis of polyurethane foam, we usually choose amine catalyst and organometallic catalyst to cooperate with each other, so as to produce synergistic effect to achieve the best effect. The specific types and proportions of amine catalysts and organometallic catalysts need to be adjusted and selected by experiments or experience according to different products, so we will not make too much statement here.

2、 Selection of Polyurethane Elastomer Catalyst

The reaction of polyurethane elastomer with NCO and water should be strictly avoided. Therefore, metal catalysts are generally used, such as organic tin, organic bismuth, and even eliminated organic mercury.

3、 Selection of Polyurethane Resin Catalyst

The reaction between NCO and water should also be avoided during the synthesis of polyurethane resin, so organic bismuth and organic tin are generally selected.