A leader in PU expertise
Polyurethanes (PU) are a leading member of the wide-ranging and highly diverse family of plastics. They play a vital role in our society, although many people are unaware of the numerous applications that provide comfort in our daily lives. The key to the success of PU foams is their seemingly endless variety. Recticel contributes to daily comfort with foam filling for seats, mattresses and box-springs of top brands; acoustic, sealing and thermal insulation material for the building, transport and industrial markets; and an extensive range of other industrial and domestic products.
Recticel’s core competence is leveraging the transformation of polyurethane chemistries into flexible foams, rigid foams and elastomers to create value-added solutions that meet existing and emerging client needs. Polyurethane transformation, although not its sole technology, remains Recticel's answer to these market needs.
How is polyurethane produced?
The petrochemical industry refines 95% of the crude oil it processes into fuels (naphtha and allied products). A wide variety of other chemicals can be distilled in one or more stages from the 5% residue, including polyol compounds and isocyanates, the main raw materials used in the production of polyurethane.
Polyurethane foam is made by reacting di-isocyanates and polyols (alcohol). This reaction is called the 'gelling' reaction since it contributes to the formation of a polymer network, or gel. The 'blowing' reaction comes from the reaction of isocyanate with water; this results in CO2 gas which expands to 'blow' the foam. Polyols may also be made from natural oils from renewable sources. When these ingredients are mixed, they react and foam.
Classification of polyurethanes
Polyurethane foams can be classified in various ways:
d ~10-100 kg/m³
d ~10-1000 kg/m³
d ~1200 kg/m³
|Slabstock||Moulded||Moulded (RIM etc)||Moulded, Spray|
|Rigid||Polyether (+PIR)||Polyether + (PIR)
A first classification can be made by differentiating non-cellular (pure polymer without foam (d ~1200 kg/m³) and cellular polyurethanes (foam with a density d ~10-100 kg/m³)). In between, micro-cellular polyurethanes have a cellular core and a non-cellular skin (d ~200-1000 kg/m³).
A second classification can be made according the hardness of the product (i.e., the force needed to obtain a deformation of the product): flexible foams, semi-rigid or rigid. It is not easy to define a clear boundary in between these categories.
A third classification can be done according to the chemical basis of the raw materials used: the base polyol being a polyether-polyol or polyester-polyol.
Finally, a fourth classification can be made according to the production process:
- Continuous block foaming (slabstock)
- Continuous foaming between two layers (double conveyor)
- Discontinuous foaming in moulds (moulding and casting)
Flexible polyurethane foams are manufactured through either a continuous slabstock production process or 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 120 metres, cured and stored for further processing.
This image shows a continuous slabstock production process.
Rigid polyurethane foams are manufactured as ready-to-use panels or in large blocks, which are then converted into more complex components. Such foams are primarily used for thermal insulation. Usually, such panels are made through continuous foaming between two layers (double conveyer).
Our R&D expertise has resulted in the development of PU with new finishes and properties. The Group primarily produces and markets semi-finished products.