In polyurethane pouring foaming molding, foaming pressure is a reliable parameter. Through measurement, it is known that during the pouring foaming process of rigid polyurethane foam, the foaming pressure changes with time. After the reaction raw materials are injected, the pressure

Gradually increase, and gradually decrease after reaching the highest value.

1、 Foaming pressure is affected by many factors

These factors include: functionality of polyol, hydroxyl value and molecular structure, isocyanate type, catalyst type and amount, foaming agent type and amount, raw material temperature, molding temperature, product size and pouring times

Generally speaking, the foaming pressure of the formulation using aromatic polyether polyols is higher than that using aliphatic polyethers such as sorbitol polyethers when other conditions are roughly the same; When the hydroxyl value of polyols is equal, the foaming pressure of materials with high functionality is higher; The foaming pressure increases with the increase of catalyst amount.

2、 Influence of mold temperature on foaming pressure

If the mold temperature is low, the foaming pressure is low, otherwise, the pressure is high. The influence of mold temperature on foaming, pressure and product surface properties,

3、 Example of pouring foaming molding formula

The chemical formula is determined according to the performance requirements of the product. The dry rigid polyurethane foam plastic has a wide range of applications. When used, its performance requirements are different. Therefore, it is difficult to use one or more chemical formulas to meet the needs of multiple uses.