| abstract |
ALLOPHANATE POLYISOCYANATES CONTAINING AT LEAST ONE AROMATICALLY BOUND-NCO GROUP ARE PREPARED BY REACTING AN N-SUBSTITUTED CARBAMIC ACID ESTER WITH ORGANIC MONO- OR POLYISOCYANATES IN THE PRESENCE OF A COMPOUND HAVING AN ALKYLATING EFFECT. THE ALLOPHANATE POLYISOCYANATES ARE OBTAINED FREE OF SECONDARY PRODUCTS HAVING ISOCYANURATE STRUCTURES, AND ARE ESPECIALLY USEFUL AS ISOCYANATE PRECURSORS IN THE PRODUCTION OF POLYUETHANE PLASTICS BY THE ISOCYANATE-POLYADDITION PROCESS. |