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US 6,048,954 AGranted
Binder compositions for laser sintering processes
AssigneeUniversity of Texas System Board of Regents
InventorsJoel W. Barlow, Neal K. Vail
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AssigneeUniversity of Texas System Board of Regents
InventorsJoel W. Barlow, Neal K. Vail
Estimating the term…
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.
An amorphous polymeric binder composition comprising an 80/20 molar ratio p(MMA-co-nBMA) methacrylate copolymer that has at least 95% mer units containing quaternary carbon atoms on the mer backbone wherein said copolymer has a T.sub.g of between about 40.degree. C. and about 100.degree. C., a melt flow index of 20-50 g/10 min and a particle size between about 50-250 nm.
An amorphous polymeric binder composition comprising a methacrylate copolymer that has at least 95% mer units containing quaternary carbon atoms on the mer backbone wherein said copolymer has a T.sub.g of between about 40.degree. C. and about 100.degree. C., a melt flow index of 20-50 g/10 min and a particle size between about 50-250 nm and further including about 2-5 mol % of a termonomer adhesion promoter.
An amorphous polymeric binder composition comprising a copolymer of methyl methacrylate and n-butylmethacrylate with a T.sub.g of about 80 to about 89.degree. C. and a melt index of about 25 g/10 min at 200.degree. C. and 75 psi extrusion pressure.
A polymer binder prepared by continuous addition of a water soluble monomer of metbacrylic acid ester and n-butylmethacrylic acid ester to an aqueous emulsion of an ionic initiator and a chain transfer agent wherein said continuous addition promotes formation of a copolymer product having a particle size of about 100 nm and a melt flow index of between 1-50 g/10 min at 200.degree. C. and 75 psi extrusion pressure.
An amorphous polymeric binder composition comprising dimethyl amino ethyl methacrylate and methacrylamide or methyl methacrylate and butyl methacrylate copolymer that has at least 95% mer units containing quaternary carbon atoms on the mer backbone wherein said copolymer has a T.sub.g of between about 40.degree. C. and about 100.degree. C., a melt flow index of 20-50 g/10 min and a particle size between about 50-250 nm.
A copolymeric methacrylate amorphous binder composition having the following properties:
A copolymeric methacrylate amorphous binder composition having the following properties:
Dependencies are inferred from the claim text.