Binder compositions for laser sintering processes

The development of polymer binder compositions that provide novel binders for high temperature inorganic particulates, especially metal and ceramic particulates is described. These materials are especially useful in a laser beam sintering process known as SLS.TM. that forms accurately shaped high strength green objects. The new binders may be thermally removed in post-shaping operations without significant residual ash. The resulting structures contain only metal, ceramic, or metal ceramic materials. The inventive methods developed for producing the new polymeric binder materials are based in part on using emulsion forms of selected polymers at controlled low molecular weights and high melt flow. An important aspect of the process is the semi-batch addition of selected chain transfer agents to the reacting emulsion. This optimizes coating characteristics of the polymer binder and results in high part strengths of the prototype parts produced in the SLS.TM. process.