Valuable secondary raw material by chemical recycling of polyisocyanurate foams

The results showed that, despite the high thermal stability claimed for isocyanurates, a glycolysis process in presence of dipropylene glycol, as glycolysis agent, and potassium acetate, as catalyst, can be successfully carried out even with PIR foams with extremely high isocyanate index. Under proper conditions, the original highly cross-linked structure of the polymer can be converted into a liquid, single phase, mixture of highly branched oligomers terminated with hydrogen active groups which was suitable to be used in the synthesis of new rigid foams. Due to the high functionality of the glycolysis products and their compatibility with isocyanates, the mechanical properties of specimens based even on high amounts (up to 75%) of glycolysis polyols turned out to be higher or either very close to those of standard specimens based on virgin polyol only.