Process for recovering polysocyanates from the distillation residues obtained in the production of tolylene diisocyanate

摘要

A process for recovering a distillate of tolylene diisocyanate and an isocyanate-group-containing sump product containing less than 200 ppm (by weight) tolylene diisocyanate from A) distillation residues obtained in the production of tolylene diisocyanate by mixing of the distillation residues A) with B) optionally urethane- and/or allophanate-modified polyisocyanates or polyisocyanate mixtures of the diphenyl methane series, heating of the mixture to 190 DEG to 250 DEG C. and simultaneously or subsequently working up by distillation.