With the expansion of the application field of polyurethane, various requirements have been put forward for the properties of polyether polyol. On the basis of continuous research, many special polyether polyols with special functions have been developed. For example, high-activity polyether polyol is developed to increase the reaction rate of polyurethane; Flame retardant polyether polyol containing halogen and other elements is developed to improve the flame retardant property of polyurethane; graft modified polyether polyol is developed to promote the resilience of products; polyether polyol with heat resistance containing different heterocyclic structures and polyether polyol with very narrow molecular weight distribution and high molecular wight are developed to improve the heat resistance of products.
Here is the introduction of high-activity polyether polyol:
The production of early polyurethane foam products adopted thermal maturation process. In order to improve the productivity and reduce the cost, when studying various catalysts, people also studied the polyether polyol in depth. They found that the polyether polyol produced by the ring-opening polymerization of propylene epoxide were all secondary hydroxyl groups. If they are converted into primary hydroxyl or amidogen, the reaction rate between these polyhydric alcohols and isocyanates will be greatly increased, and a type of high-activity polyether can be developed based on this theory. Thus, new technologies such as cold curing process and reaction injection moulding as well as new products such as self-skinning foam and high resilience foam are introduced.
At present, two approaches are basically adopted in the preparation of polyether polyol with high activity: substitute primary hydroxyl group or amidogen for the secondary hydroxyl group of a common polyether end group.