Curing and heat transfer in polyurethane reaction molding

Temperature measurements were made on the adiabatic polymerization of three urethane systems; two casting formulations, one thermoplastic and the other thermosetting, and a commercial reaction injection molding (RIM) formulation with a 10 second gel time. The data were found to fit a simple nth order overall kinetic expression. These kinetic and heat of reaction results were used to model heat transfer in a 3.8 cm diameter cylinder with an isothermal wall. Experimental temperature profiles for the two casting urethanes were in good agreement with predictions. The kinetic data on the RIM material was used to model temperature profiles1 in 3 and 6 mm thick plaque molds. Experimental measurements of temperature near the mold center agreed with the model. Temperatures measured near the wall were higher due to failure of the isothermal wall assumption.