ABSTRACT
With reinforced reaction injection molding (RRIM), parts are more resistant to temperature changes than those from unreinforced reaction injection molding (RIM). In RIM two highly reactive liquid monomers are carefully metered, brought together in a mixhead, and immediately injected into a heated mold under low pressure. The economics affecting these choices are based on his production volumes and technical capabilities. A variety of reinforcing materials has been used with varying degrees of success. Milled glass fibers are most commonly used and presently are the product of choice. In either case, proper storage and handling to protect the materials from contamination degradation are vital. Moisture contamination can be prevented by topping the storage tanks with a blanket of dry gas, preferably nitrogen. OSHA regulations and safety requirements for reaction injection molding apply equally to RRIM. Exact properties are influenced by the urethane system, the reinforcement material, the material characteristics, and the reinforcement loading.
