PROCESS OF PREPARING CYCLIC UREA-FORMALDEHYDE PREPOLYMER

摘要

The preparation of a high parity cylic-urea-formadehyde prepolymer (cyclic urea prepolymer) is performed at a temperature of at least 85 DEG C and a pH between 7 and 9, whereby per mole of urea at least 4 mole formaldehyde and 0.5 - 1.2 mole of ammonia or primary amine is added. The obtained prepolymer must have a triazone content of at least 75 % as measured with C-13 NMR.