Studies of mold filling and curing in the reaction injection molding process

A model is developed for pressure rise, extent of reaction and temperature changes during filling and curing in thin rectangular molds for the reaction injection molding (RIM) process. The predictions of the model are shown to be in good agreement with experimental results obtained for several intrumented molds using polyurethane RIM chemical systems. The relevant dimensionless groups are identified. Criteria for good mold filling are developed.