FORMULATION OF INJECTION MOLDING BINDER SYSTEMS

A polyethylene and three ethylene vinyl acetate (EVA) copolymers were evaluated to determine the best mix of binder components. The effect of plasticizers and processing aids was investigated. One weight percent of silane coupling agent was added to improve the ceramic and binder mix stability. These mixes were evaluated from the Brabender torque data and capillary viscosity. A limited number of molding experiments were also performed. The results showed that polyethylene and EVA copolymers with a melt index of around 25 are the most suitable binders, that plasticizers improve the flowability of the mix; and that processing aids containing a double bond and amines reduce viscosity and improve moldability. Combining plasticizers, processing aids and a small concentration of an appropriate coupling agent results in a low primary binder concentration. EVA mixes have shown better flow and moldability.