How is PU foam made?

Polyurethane foam is made by reacting di‐isocyanates and polyols. Both of these products are derived from crude oil. Polyols may also be made of natural oils from renewable sources. When these ingredients are mixed, they react and foam.

We can influence the properties of the foam during production by using different types of chemicals, adding other materials or through specific processing techniques. This flexibility offers tremendous opportunities

Flexible polyurethane foam (‘PU foam’) is a thermosetting plastic. It is used in a very wide range of durable applications, notably in mattresses, upholstered furniture and in vehicles. As an example, nearly 90% of mattresses produced in the EU contain polyurethane foam and over 90% of furniture upholstery is made of PU foam. The EU’s production of flexible polyurethane foam is of around 900,000 tonnes per annum.

PU flexible foams are manufactured through a continuous slabstock production process or through a discontinuous (moulded) process. In the continuous process, the foam rises within seconds after mixing the ingredients on a moving conveyor and then solidifies. In theory foam blocks of several kilometres in length could be produced this way. In reality, the foam blocks are typically cut at a length of between 15 and 120m, cured and stored for further processing. 
 

Polyurethane foam. We rarely see it, yet it is all around us: in cars, mattresses, sofas, clothing... This video explains how it is actually made.