Environmental protection pressure has prompted some traditional solvent-based products to gradually withdraw from the market and replace them with water-based, high solid content, powder products, etc.Waterborne polyurethane, as an important member of waterborne products, is facing unprecedented development opportunities with its unique excellent properties.In addition to the leather industry, it is used in textile finishing, coatings, medical materials, glass fiber, plastic parts, automotive interior parts, card production and other industries.The research topic related to waterborne polyurethane is becoming a hot topic in recent years. There are more and more research projects related to waterborne polyurethane, and more and more scientific research institutions and universities are participating in the exploration. Their work is mainly reflected in the following aspects.There are more and more research projects related to waterborne polyurethane, and more and more scientific research institutions and universities are participating in the exploration. Their work is mainly reflected in the following aspects.

Crosslinked modified waterborne polyurethane is mostly linear structure, its water resistance, solvent resistance and heat resistance is relatively poor, the introduction of crosslinked structure, can be effectively improved.According to the internal crosslinking method, partial branching and crosslinking structures can be formed by introducing three functional compounds.This kind of method can improve the performance of the film, its main disadvantage is that the molecular weight of the prepolymerization is large, resulting in emulsification difficulties, difficult to produce water-based polyurethane with high solid content, so the drying performance is relatively poor. The more feasible is to use the diplomatic association method, although the method is more troublesome in application, but it is really effective, and can significantly enhance the drying speed, and the improvement of performance is especially obvious.In which the key cross-linker cured at room temperature is water, which can disperse polyisocyanate and polyaziridine. In recent years, there are many researches on water-dispersible polyisocyanates, but not many have been published. Some domestic manufacturers are trying to launch, but the performance stability needs to be improved. Another kind of crosslinked modified product is closed waterborne polyurethane. The synthesis of this type of product is difficult to control, and the products produced are not stable, but it will be a key direction in the future, especially in the textile function finishing, paint printing and other industries have great room for display.