Polyurethane-prepolymers are used to make a variety of materials and products, including foams, glues and hot melts, gaskets, coatings and solid rubber. Prepolymers are made by reacting polyols with isocyanates. Isocyanates are a group of highly reactive chemicals characterised by the presence of an isocyanate group (–N=C=O). Some isocyanates such as toluene diisocyanate (TDI), are considered highly hazardous and toxic. After reaction, the isocyanate levels in the product are excessive. To achieve a safe and competitive product that meets international regulations, this excess must be removed.
Link to further information: Case Study Isocyanates