CPC B22C 1/02 (2013.01) [B22C 1/2273 (2013.01)] | 20 Claims |
1. A foundry mix composition, comprising:
a polyurethane binder precursor, provided in two parts, the first part comprising a polyol component and the second part comprising a polyisocyanate component;
a liquid curing catalyst;
a foundry aggregate; and
a halloysite clay, present in the range of from about 1 to about 4 wt %, based on the weight of the foundry aggregate.
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15. A method for preparing a foundry mix, comprising the steps of:
adding a halloysite clay to a foundry aggregate and mixing, wherein the halloysite clay is present in an amount in the range of about 1 to about 4 wt %, based on the weight of the foundry aggregate;
adding, to the mixed halloysite clay and foundry aggregate, a first part of a polyurethane binder precursor and a liquid curing catalyst and mixing, the first part of the polyurethane binder precursor comprising a polyol component; and
adding a second part of the polyurethane binder precursor, the second part of the polyurethane binder precursor comprising a polyisocyanate component.
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19. A foundry mold or core, comprising the foundry mix composition according to claim 1.
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20. A no bake process for preparing a foundry shape, comprising the steps of:
providing an amount of the foundry mix composition of claim 1;
mixing intimately the halloysite clay with the foundry aggregate;
preparing a foundry molding compound by separately mixing the polyurethane binder precursor and the liquid curing catalyst with the mixed halloysite clay and foundry aggregate;
inserting the foundry molding compound into a pattern, allowing the mixture to cure into a foundry shape, and
removing the foundry shape from the pattern.
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