The action mechanism of polyurethane defoamer is complex and diverse. Defoamer molecules can rapidly diffuse to the surface of foam, reduce the surface tension of foam liquid film, and make foam unstable and easy to break. Defoamer molecules can penetrate into the liquid membrane of foam, destroy its structural integrity, and make foam collapse rapidly. In addition to destroying the generated foam, defoamers can also form a film on the liquid surface to prevent the generation of new foam. Some defoamers can also slow down the generation of foam by increasing the viscosity of the system. In practical applications, the mechanism of action of defoamers is often the result of multiple mechanisms working together to achieve the best defoaming and anti foaming effects.

When selecting high-efficiency defoamer for polyurethane, the following criteria should be comprehensively considered: it can quickly destroy the foam structure, reduce the impact of foam on production, maintain the inhibition on foam for a long time, and prevent foam regeneration. Maintain good compatibility with polyurethane raw materials and additives, without affecting the performance and quality of the product. It can maintain stable performance under harsh conditions such as high temperature and high pressure. Compliant with environmental regulations and harmless to human health and the environment. In addition, factors such as the cost-effectiveness of defoamers and the service quality of suppliers need to be considered.