The "Sun Wukong" of the light-curing resin industry, watch me transform into 72 different forms

In the large family of photocurable resins, in addition to the "tough guy" epoxy acrylate, another important type of resin is polyurethane acrylate, which is abbreviated as PUA. This all-round talent has shown his prowess in the fields of photocurable coatings, inks, adhesives, etc. Although it is slightly inferior to epoxy acrylate, it is also quite popular. It is synthesized from raw materials such as long-chain diols, polyisocyanates and hydroxy acrylates. Since these three raw materials have a variety of structures and models to choose from, through clever molecular design, whether it is flexibility, hardness or wear resistance, PUA can be "designed" in advance to meet the needs of different scenarios. This flexibility makes PUA the one with the "most product brands" among photocurable resins.

Its synthesis process is through precisely controlled chemical reactions，to combine the active group isocyanate (-NCO) in isocyanate with the hydroxyl group (-OH) in long-chain diol and acrylate hydroxy ester，to form a stable carbamate (-NHCOO-) structure.

In the PUA family, according to the structural classification of isocyanates，polyurethane acrylates can be divided into aliphatic PUA and aromatic PUA . Aliphatic PUA is a PUA made from aliphatic and alicyclic isocyanates. It is famous for its excellent light resistance, weather resistance, non-yellowing, low viscosity, and good flexibility. It has good overall performance, but the price is relatively high. Aromatic PUA, which is synthesized from aromatic isocyanates, appears rigid because it contains benzene rings. The mechanical strength and hardness of the cured film are very high, the heat resistance is good, and the price is affordable, but it is a bit "easy to yellow" and has poor weather resistance.

According to the number of functional groups, common polyurethane acrylates include difunctional, trifunctional, tetrafunctional, hexafunctional, nonafunctional, etc. Theoretically, the more functional groups there are, the faster the curing rate, the higher the hardness, the better the wear resistance and the better the chemical resistance.

According to the structural type of long-chain diols, polyurethane acrylates can be divided into polyether and polyester polyurethane acrylates. Polyether polyurethane acrylates are known for their excellent flexibility and low viscosity. Due to the low cohesive energy of the ether bonds in the polyether, the material is endowed with good flexibility, making the cured film soft and elastic. However, polyether products are relatively weak in mechanical properties and heat resistance and are suitable for applications requiring high flexibility. In contrast, polyester polyurethane acrylates stand out for their excellent mechanical strength and heat resistance. The polyester bond gives the material higher tensile strength and modulus, making it perform well in applications requiring high mechanical properties. However, polyester bonds are easily hydrolyzed in alkaline environments, which limits its application in certain specific environments.

As one of the key resins in the field of photocuring, polyurethane acrylate plays an increasingly important role in modern industry with its unique performance advantages. Although its price is slightly higher than that of traditional epoxy acrylate, polyurethane acrylate has shown irreplaceable value in improving product performance. In photocuring formulas, polyurethane acrylate is usually not used as the main resin, but as an auxiliary resin to optimize product performance. For example, due to its excellent flexibility and adhesion，difunctional polyurethane is often used to adjust the flexibility of the cured film， and reduce the shrinkage rate during the curing process , thereby improving the durability and stability of the product. Hexafunctional polyurethane is used to increase the hardness of the cured film, promote surface drying, and enhance the product's wear resistance due to its hardness and wear resistance. When choosing polyurethane acrylate, it should be decided based on the performance requirements of the cured film of the final product.

With the continuous advancement of light-curing technology, the application potential of polyurethane acrylate is gradually being explored. By carefully designing the formula and selecting the appropriate polyurethane acrylate, BOSSIN, as a manufacturer of photocurable resin, can provide polyurethane acrylate products with excellent performance for various application fields. You are welcome to call us for consultation.