PROCESS FOR THE PREPARATION OF OPTICALLY TRANSPARENT MELAMINE-FORMALDEHYDE OLIGOMER

摘要

A process for the preparation of optically transparent melamine-formaldehyde oligomer involves polycondensation of melamine and formaldehyde, distillation, oligomer cross-linking. To improve optical characteristics and to simplify the process the melamine and formaldehyde polycondensation is carried out in the presence of polyols in one step at 80-100 °С for 45 min., and distillation is carried out at 110 °С for 60 min. with following oligomer cross-linking at 110-120 °С for 6 hours.