Polyurethanes polyisocyanate starting materials

Reaction injection moulding is associated with polyurethanes and is different entirely from moulding techniques used commonly for thermoplastics in that the starting materials usually are liquids at room temperature. As the name implies, a chemical reaction takes place in the course of moulding and complex polyurethane items can be made in one step from mixtures comprising polyol, polyisocyanate, and a suitable promoter of the reaction. 

This plastic includes a large group of polyaddition polymers which are formed through the reaction of bifunctional or trifunctional alcohols with di- or polyisocyanates. By varying the starting materials, linear as well as crosslinked macromolecules with correspondingly different properties are formed. Alcohols with three functional groups and/or triisocyanate are used to make crosslinked polyurethane elastomers (PUR). 

Table 3.6 Polyisocyanate and polyol starting materials for polyurethanes...

Table 3.6. Polyisocyanate and Polyol Starting Materials for Polyurethanes[2 H28]... 

Although these new lightweight porous materials were envisioned as supportive materials as well as insulative materials in the base patents [3,4] their market development remained slow. This can be seen by the fact that even in 1952 polyisocyanates, mainly toluene diisocyanate (TDI), were available worldwide in quantities of less than 100 tonnes. After this rather hesitant start of polyurethane history and the first major switch from solid materials to porous foamed plastics, the industry has been characterised by significant changes in concept and the resulting industrial application of these switches. 

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