Quick-Setting Polyurethane Adhesives.

As an introduction general treatment is given to the effect of accelerators in PU systems as well as to factors influencing the accelerator effect. On the basis of concrete examples the relationship between the pot life, the open time and the setting process on the one hand and the accelerator concentration on the other is represented. Rules can be set up on the relationship between these factors which are of considerable importance for practical work with adhesives. No difference was found in the strength of adhesives with and without accelerators in the course of aging tests under various environmental conditions. Special treatment is given to the industrial use of accelerated PU adhesives in particular in the manufacture of composite materials. Here the deployment of automatic proportionating mixers plays an important role since highly accelerated adhesives can only be processed by this means.