Urea-formaldehyde resin should gradually improve its water resistance and aging resistance

Urea-formaldehyde resin adhesive is the most synthetic synthetic resin adhesive used in China's wood industry, accounting for more than 60% of the total consumption of wood processing industry adhesives, accounting for about 90% of the amount of plastic used in wood-based panels. Urea-formaldehyde resin adhesive has many advantages: high bonding strength, high cold water resistance, moderate heat-resistant water performance; rapid curing; good miscibility with water, easy to adjust suitable viscosity and concentration. But the fundamental reason for its large amount is the price advantage - it is the lowest price among synthetic resin adhesives. However, urea-formaldehyde resin adhesives and their glued products will continuously release formaldehyde during use, which is harmful to the human body, which greatly limits its scope of use.

Li Jianzhang, an associate professor at the School of Materials Science and Technology, Beijing Forestry University, mentioned in the article "Research Progress in Low-toxicity Modifiers for Urea-Formaldehyde Resin Adhesives" that the addition of modifiers is an important direction in the study of low toxicity of urea-formaldehyde resin adhesives. The latest research results are reviewed from the sources of toxicity of urea-formaldehyde resin adhesives, the research progress of urea-formaldehyde resin adhesive low-toxicity modifiers at home and abroad, and the selection principle of modifiers. He believes that the main problems faced by urea-formaldehyde resin adhesive low-toxicity modifiers are still high cost, other physical and chemical properties such as the bonding strength of modified resin, and the decrease of production efficiency of artificial board (prolonged hot pressing time). . In the future, research should be strengthened on the reaction mechanism between low-toxicity modifiers and resins, in order to study and develop modifiers with good effect, low dosage and low cost, so that the urea-formaldehyde resin low-toxicity modifier can achieve a real large scale. Industrial production and application.

The "Research Progress of Urea-Formaldehyde Resin Adhesives" also suggested that urea-formaldehyde resin adhesives have the disadvantages of poor water resistance, high brittleness of cured products, poor aging resistance and high free formaldehyde content, thus limiting their use range, especially the high free formaldehyde content. The problem. In the future, the development direction of urea-formaldehyde resin is still to develop and promote products with low free formaldehyde content and low formaldehyde emission of cemented products, and improve their water resistance and aging resistance. With the introduction and application of various new methods, new ideas and new technologies, various problems of urea-formaldehyde resin adhesives will be gradually solved.