（The foaming pressure is a noteworthy parameter in cast foam moulding (PUR). It has been determined that the foaming pressure varies with time during the casting and foaming of rigid polyurethane foam. After the reaction material is injected, the pressure rises gradually, reaches its highest value and then gradually decreases.
A. Foaming pressure is influenced by a number of factors
These factors are: the polyol's functionality, hydroxyl value and molecular structure, isocyanate species, catalyst species and dosage, foaming agent species and dosage, raw material temperature, mould temperature, product size and casting times, etc..
In other conditions are generally the same, generally speaking, the use of aromatic polyether polyol formula foaming pressure than the use of sorbitol polyether and other aliphatic polyether for the high; polyol hydroxyl value of equal, high functionality of the raw material foaming pressure is higher; catalyst dosage increases, foaming pressure also increases with.
B. Mould temperature has a significant influence on foaming pressure
Low mould temperatures result in low foaming pressures and conversely high pressures. Influence of mould temperature on foaming pressure and product surface properties
C. Example of a poured foam moulding formulation
The chemical formulation is determined by the performance requirements of the product. As rigid polyurethane foam has a wide range of applications and is used with varying performance requirements, it is difficult to use one or several chemical formulations to meet the needs of multiple applications.
