Mehrstufiges Verfahren zur kontinuierlichen Herstellung von organischen Polyisocyanaten

摘要

The invention relates to a multi-step method for the continuous preparation of organic polyisocyanates, preferably aliphatic or cycloaliphatic diisocyanates, by conversion of the corresponding organic polyamines with carbonic acid derivatives and alcohols into monomeric polyurethanes and thermal cleavage thereof, in which the prepared polyiisocyanates and unutilizable residues are separated off in specific reaction steps and the reutilizable by-products are fed back into preliminary steps.