Sand compositions for foundry cores and molds comprising alkali metal silicate binders and acrylamide polymer or water-soluble sulfonated alkenyl aromatic polymer additives, their preparation and use

Claim 1

THE METHOD OF CASTING METALS WHICH COMPRISES MIXING BETWEEN ABOUT 97 AND ABOUT 90 PERCENT BY WEIGHT, BASED ON THE WEIGHT OF THE RESULTING COMPOSITION, OF SAND WITH BETWEEN ABOUT 3 AND ABOUT 10 PERCENT BY WEIGHT, BASED ON THE WEIGHT OF THE RESULTING COMPOSITION, OF AN AQUEOUS DISPERSION OF AN ALKALI METAL SILICATE OF AN ALKALI METAL OF ATOMIC NUMBER 3 TO 19 HAVING A SILICATE CONCENTRATION OF AT LEAST ABOUT 10 PERCENT BY WEIGHT AND A SILICA TO ALKALI METAL RATIO OF AT LEAST 0.5:1, SAID COMPOSITION CONTAINING A MINOR PROPORTION OF BETWEEN ABOUT 0.001 AND 0.1 PERCENT BY WEIGHT, BASED ON THE WEIGHT OF THE AQUEOUS DISPERSION OF ALKALI METAL SILICATE IN THE WET SAND COMPOSITION, OF A POLYMERIC ORGANIC ADDITIVE SELECTED FROM THE GROUP CONSISTING OF WATER-SOLUBLE ACRYLAMIDE POLYMERS THAT CONTAIN IN THE POLYMER MOLECULE AT LEAST ABOUT 85 PERCENT BY WEIGHT OF POLYMERIZED ACRYLAMIDE, ANY BALANCE BEING ANOTHER POLYMERIZED MONETHYLENICALLY UNSATURATED MONMERIC MATERIAL MATERIAL THAT IS COPOLYMERIZABLE WITH ACRYLAMIDE, WATER-SOLUBLE SULFONATED ALKENYL AROMATIC POLYMERS CONSISTING OF AT LEAST ONE POLYMERIZED ALKENYL AROMATIC COMPOUND HAVING THE GENERAL FORMULA: G-CX=CH2, WHEREIN G IS AN AROMATIC RADICAL AND X IS TAKEN FROM THE CLASS CONSISTING OF HYDROGEN AND METHYL, AND THEIR MIXTURES; FORMING A MOLD OF THE RESULTING SAND COMPOSITION; POURING THE METAL WHILE MOLTEN IN THE RESULTING MOLD; AND THEREAFTER SOLIDIFYING THE METAL IN SAID MOLD BY COOLING IT THEREIN TO A TEMPERATURE BENEATH ITS MELTING POINT.

Claim 2

THE METHOD OF CASTING METALS WHICH COMPRISES MIXING BETWEEN ABOUT 97 AND ABOUT 90 PERCENT BY WEIGHT, BASED ON THE WEIGHT OF THE RESULTING COMPOSITION, OF SAND WITH BETWEEN ABOUT 3 AND ABOUT 10 PERCENT BY WEIGHT, BASED ON THE WEIGHT OF THE RESULTING COMPOSITION, OF AN AQUEOUS DISPERSION OF AN ALKALI METAL SILICATE OF AN ALKALI METAL OF ATOMIC NUMBER 3 TO 19 HAVING A SILICATE CONCENTRATION OF AT LEAST ABOUT 10 PERCENT BY WEIGHT AND A SILICA TO ALKALI METAL RATIO OF AT LEAST 0.5:1, SAID COMPOSITION CONTAINING A MINOR PROPORTION OF BETWEEN ABOUT 0.001 AND 0.1 PERCENT BY WEIGHT, BASED ON THE WEIGHT OF THE AQUEOUS DISPERSION OF ALKALI METAL SILICATE IN THE WET SAND COMPOSITION, OF A POLYMERIC ORGANIC ADDITIVE SELECTED FROM THE GROUP CONSISTING OF WATER-SOLUBLE ACRYLAMIDE POLYMERS THAT CONTAIN IN THE POLYMER MOLECULE AT LEAST ABOUT 85 PERCENT BY WEIGHT OF POLYMERIZED ACRYLAMIDE, ANY BALANCE BEING ANOTHER POLYMERIZED MONETHYLENICALLY UNSATURATED MONMERIC MATERIAL MATERIAL THAT IS COPOLYMERIZABLE WITH ACRYLAMIDE, WATER-SOLUBLE SULFONATED ALKENYL AROMATIC POLYMERS CONSISTING OF AT LEAST ONE POLYMERIZED ALKENYL AROMATIC COMPOUND HAVING THE GENERAL FORMULA: G-CX=CH2, WHEREIN G IS AN AROMATIC RADICAL AND X IS TAKEN FROM THE CLASS CONSISTING OF HYDROGEN AND METHYL, AND THEIR MIXTURES; FORMING A MOLD OF THE RESULTING SAND COMPOSITION; POURING THE METAL WHILE MOLTEN IN THE RESULTING MOLD; AND THEREAFTER SOLIDIFYING THE METAL IN SAID MOLD BY COOLING IT THEREIN TO A TEMPERATURE BENEATH ITS MELTING POINT.