Polyurethane is a rigid foam which is produced by joining polyol and isocyanate under special conditions with the presence of catalysts and other materials.
It is a foam in which most of the foam cells remain closed. This gives the foam a high thermal insulation performance. Polyurethane can be produced in any required density. To obtain the required thermal conductivity and load bearing capability, the foam`s density should be between 40 kg/m3 and 42 kg/m3. Rigid polyurethane foam is a dimensionally stable material. It can not be saturated. The maximum service temperature for rigid polyurethane is 70°C – 80°C.Polyurethane stays thermally stable up to 100°C – 110°C. Above these temperatures, disintigration starts. It is a bacterial growth free material.
Since polyurethane has a high compressive strength, it is used in wide-range applications. PIR (Polyisocyanurate) is an improved type of polyurethane and used for composite section insulated panels. PIR foam is thermal stability much stronger and can meet the requirements of Euroclass B.