Introduction to slow rebound polyether polyols

The slow rebound mechanism of polyurethane foam is due to the degree of phase separation of the polyurethane system and its special vitrification Caused by the transition temperature, the material has two glass transition temperatures, one glass transition temperature is between 0~100 ℃, and the other glass transition temperature is – Between 60~-20 ℃. Due to this particularity of the material, when subjected to external impact, both elastic deformation (energy-storage deformation, satisfying Hooke’s law) and plastic deformation (energy-consuming deformation, with irrecoverable characteristics) occur. Plastic deformation can absorb most of the impact energy, while part of the energy accumulated in elastic deformation can slowly return the slow-rebound polyurethane foam to its original shape after the external pressure is removed. Therefore, the preparation of slow rebound polyurethane foam usually requires the use of special slow rebound polyether polyols to change the glass transition temperature (Tg) of the material so that it has both viscous deformation and elastic deformation at the use temperature. characteristic. Slow rebound polyether polyol is not a single polyether polyol, but is generally a mixture of two or more polyether polyols, with a molecular weight between 100 and 1500. Mainstream foreign brands include 207 from the American Dow Company, 1030 produced by South Korea’s SKC Company, and LR00 produced by Japan’s Mitsui. Currently, the domestically developed slow rebound polyether polyols mainly include Shanghai Gaoqiao Petrochemical GLR2000 and Nanjing Zhongshan Chemical 1070, etc. .

Preparing slow rebound foam usually requires the use of special slow rebound polyether polyols. It is prepared to change the Tg of the material so that it has the dual characteristics of viscous deformation and elastic deformation at the use temperature. Many slow-rebound polyether polyols are similar to polyether polyols used in hard foam. They have lower molecular weight and more short branched structures in the molecules. Therefore, the foam produced has some shortcomings, such as tensile strength, elongation. The mechanical properties such as rate are poor; in addition, due to the formation of the initial network structure, the fluidity of the material in the early stage of foaming is poor.