Process for making dicyclopentadiene polyetherester resins

摘要

A low-cost way to modulate the reactivity and acid number of polyetherester thermoset resins is disclosed. "Beginning" and "end" methods for making dicyclopentadiene (DCPD)-modified polyetherester resins are described. The "beginning" method comprises first heating a polyether, DCPD, a diol, an insertion catalyst, and a carboxylic acid derivative to produce a mixture that contains the polyether and a DCPD-diol diester adduct. Increasing the temperature causes insertion of the DCPD-diol diester into the polyether to give a DCPD polyetherester resin. The "end" method reacts a polyetherester resin made by insertion with DCPD to give a DCPD polyetherester resin. Compared with DCPD polyester resins, those of the invention give more flexible thermosets. Compared with unmodified polyetherester resins, the DCPD polyetherester resins offer formulators more control over curing, which eliminates mold distortion and shrinking or cracking of thermoset parts. Thermosets from blends of the subject resins and DCPD polyester resins show synergistic property improvements compared with thermosets from either resin alone.