Den-Mat Corporation

Rachel R Pineda

Thomas C Chadwick

Robert L Ibsen

Alan B Matthews

Methods for making molding casts by a process typically referred to as &ldquo;investment casting&rdquo; using a novel composition is described. The composition is a phosphate bonded material that contains mono-ammonium phosphate (MAP), magnesium oxide and silica filler (quartz, cristobalite, or a mixture thereof). It has been discovered that controlling the amount and ratio of these components has a significant impact on gas permeability (porosity), set time, cast smoothness and cast softness. The most outstanding feature of the new investments is the short mold fabrication and processing time that they allow due to their high gas permeability. The investments can be placed in a burn out furnace while still wet and can be heated rapidly to the firing temperature. The casts can be broken by sandblasting the casts with glass beads. Molds made from the casts have smooth surfaces indicating that the casts are free of visible inclusions and other defects.

Phosphate investment compositions and methods of use thereof

An investment composition is described for use in investment casting (also called lost wax casting). The composition is a phosphate bonded material that contains mono-ammonium phosphate (MAP), magnesium oxide and silica filler (quartz, cristobalite, or a mixture thereof). It has been discovered that controlling the amount and ratio of these components has a significant impact on gas permeability (porosity), set time, cast smoothness and cast softness. The most outstanding feature of the new investments is the short mold fabrication and processing time that they allow due to their high gas permeability. The investments can be placed in a bum out furnace while still wet and can be heated rapidly to the firing temperature. The casts can be broken by sandblasting the casts with glass beads. Molds made from the casts have smooth surfaces indicating that the casts are free of visible inclusions and other defects.

Phosphate investment compositions

The instant invention relates to an anhydrous dentifrice (toothpaste, brushing gel, etc . . . ) The dentifrice is a homogeneous mixture of the following compounds: (1) organic polyols, such as glycerin; (2) cooked starch gelling agents; (3) mildly abrasive fillers such as silica, alumina and dicalcium phosphate; and, optionally, (4) compounds selected from the group consisting of anti-caries agents, anti-plaque agents, anti-calculus agents, bleaching agents, peroxide stabilizers, desensitizing agents, whiteners, anti-stain agents, breath fresheners, flavorants, sweeteners, colorants, buffers, surfactants, and anti-bacterial agents, with the proviso that if bleaching agents are employed then peroxide stabilizers must also be employed. Preferably, the dentifrice does not contain any gelling agent other than the cooked starch particles.

Growing community of inventors

Santa Maria, CA, United States of America

Rachel R Pineda