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US 6,303,664 B1Granted
Treatment for reducing residual carbon in the lost foam process
AssigneeStyroChem Delaware, Inc.
InventorsFred Sonnenberg, Kyösti Matti Taristo, Tom Verner Johannes Johansson
Life of this patent
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Abstract
The evaporative casting of molten metals has been shown to produce castings having smooth surfaces with significantly less signs of carbon deposits thereon by using an expandable vinyl aromatic polymer containing a bromine-attached aliphatic or aromatic flame retardant.
Claims19
A process for preparing a pattern for use in making metal castings which have significantly less residual carbon on the surface comprising:
- (a) adding an amount, effective for the purpose, of a hexabromocyclododecane or tetrabromocyclooctane flame retardant to a vinyl aromatic monomer;
- (b) suspending the monomer in water using a suitable suspending agent system;
- (c) adding a suitable blowing agent to the partially polymerized suspension and heating to impregnate the particles;
- and
- (d) separating the impregnated beads from the aqueous suspension, washing and drying the beads,
- wherein said surface is selected from the group consisting of bronze, brass, ductile, modular or grey iron, magnesium and steel.
3 more elements
A process for preparing a pattern for use in making metal castings, which have significantly less residual carbon on the surface comprising:
- (a) adding an amount, effective for the purpose, of a flame retardant selected from the group consisting of hexabromocyclododecane and tetrabromocyclooctane to a vinyl aromatic monomer;
- (b) suspending the monomer in water using a suitable suspending agent system;
- (c) adding a suitable blowing agent to the partially polymerized suspension and heating to impregnate the particles;
- and
- (d) separating the impregnated beads from the aqueous suspension, washing and drying the beads,
- wherein said surface is selected from the group consisting of bronze, brass, ductile, modular or grey iron, magnesium and steel.
3 more elements
Dependencies are inferred from the claim text.