Fillers for investment and refractory die materials
AssigneeJeneric/Pentron Incorporated
InventorsArun Prasad, Carlino Panzera
Life of this patent
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Abstract
Phosphate-bonded investments and refractory die materials are provided upon which dental porcelains and/or alloy powders can be sintered. Inorganic fillers are mixed with appropriate binders to produce mold materials which exhibit very high thermal expansion properties without exhibiting any large or sudden change in their thermal expansion verse temperature profile. Investments and refractory die materials having thermal expansions of greater than 0.80% in the range of 25.degree.-500.degree. C. are provided by incorporating leucite (KAlSi.sub.2 O.sub.6) or calcium difluoride (CaF.sub.2), or both, as fillers for investments and refractory die materials.
Claims18
An investment and refractory die material upon which a dental porcelain or alloy is heated, said investment and refractory die material comprising by weight:
- (A) about 50 to about 80 percent filler, said filler containing greater than about 50 percent by weight based on said filler of at least one member selected from the group consisting of leucite and calcium difluoride;
- and
- (B) about 20 to about 50 percent of a phosphate-containing binder, wherein the thermal expansion of said investment and refractory die material is greater than about 0.8 percent when heated from about 25.degree. C. to about 500.degree. c.
An investment and refractory die material upon which a dental porcelain or alloy powder is sintered, said investment and refractory die material consisting essentially of:
- (A) about 50 to about 80% by weight filler, said filler containing greater than about 50% by weight based on said filler of at least one members selected from the group consisting of leucite and calcium difluoride;
- and
- (B) about 20 to about 50% by weight of a phosphate-containing binder, wherein the thermal expansion of said investment and refractory die material is greater than about 0.8% when heated from about 25.degree. C. to about 500.degree. C.
Dependencies are inferred from the claim text.