PU foams can basically be categorized in two ways:
1. type of application or properties of the foam: rigid, semi-rigid, flexible foam
2. type of blowing agent used: chemically foamed (water), physically foamed
In addition, there are special systems as well as combinations of the individual methods, with water being the most frequently used chemical foaming agent. It reacts with the isocyanate present and forms amines and CO2, which acts as a blowing agent.
Here, the different chemical reactions that take place and the prevailing boundary conditions must be precisely coordinated in order to ultimately produce a PU foam with good properties. The starting components, the foaming behaviour and the foam cells (open-cell – closed-cell) that are created ultimately determine the area of application.
Typical applications for PU foams are Upholstery materials, mattresses, automotive interior, sound and heat insulation and many more.
PU foams are primarily characterized by the processing properties of the starting components and the foaming behaviour as well as the hardness, pressure properties and cell structure of the resulting component.