| 초록 |
Wastes of PU foams are being generated in recycling centers of refrigerators and automotives. Current technologies for the recycling of PU wastes are limited to some physical recycling of powders and chemical recycling. Recently, we have developed a non-phosgene process to prepare polyisocyanates from aminolysis products of polyurethane wastes. The recycled polyisocyanates prepared from depolymerized product of waste rigid polyurethane foam were mixed with a commercial polymeric 4,4-diphenyl methane diisocyanate (p-MDI) and used to prepared rigid polyurethane foams (PUF) with a poly (propylene glycol), PPG-640. Reactivities and densities of the PU system based on PPG-640 and various polyisocyanate mixtures are given in Table 1. Reactivity of the PU system was lowered with increasing the contents of recycled polyisocyanates. The PU foams obtained from the mixture of polyisocyanates have comparable properties with those of the PU foams prepared with p-MDI only. |
