Abstract: There are disclosed methods and compositions for retarding the ambient temperature hardening of a phenolic resole resin alone or with an aggregate when such resin is contacted with a nitroalkane and a hardening agent such as lightburned magnesium oxide, an organic ester functional hardening agent, and mixtures of lightburned magnesium oxide and an organic ester functional hardening agent in an alkaline medium. There is also disclosed a hardener composition for phenolic resole resins wherein the hardener composition consists essentially of a solution of a nitroalkane in an organic ester functional hardening agent.

Abstract: The present invention provides methods for treating reclaimed sand obtained from dismantled foundry molds and cores which contain a cured binder derived from an ester cured alkaline phenolic resin. Treatment of the reclaimed sand with a silane solution, particularly an aqueous solution, enhances the tensile strengths of foundry molds and cores produced therefrom beyond those obtained with untreated reclaimed sand. Methods for producing foundry cores and molds which incorporate such a treatment process are also provided by this invention as are raw batch formulations.

Abstract: The present invention provides a binder solution having a low solids level which provides improved tensile properties when used with reclaimed sand. This binder solution comprises an alkaline phenolic resin which is cured at ambient temperature with an ester-functional curing agent. Also provided by this invention are raw batch formulations comprising sand, a binder solution having a low solids level, and a curing agent. These raw batch formulations include embodiments wherein the low solids levels are obtained by the separate addition of a solvent. The methods for producing foundry molds and cores of this invention included those procedures wherein dilution water is used to reduce the solids contents of conventional, relatively high solids content binder solutions.

Abstract: The present invention provides methods for treating reclaimed sand obtained from dismantled foundry molds and cores which contain a cured binder derived from an ester cured alkaline phenolic resin. Treatment of the reclaimed sand with a silane solution, particularly an aqueous solution, enhances the tensile strengths of foundry molds and cores produced therefrom beyond those obtained with untreated reclaimed sand. Methods for producing foundry cores and molds which incorporate such a treatment process are also provided by this invention as are raw batch formulations.

Abstract: The present invention provides methods for treating reclaimed sand obtained from dismantled foundry molds and cores which contain residue from a cured binder of an ester-cured alkaline phenolic resin. Treatment of the reclaimed sand with a silane solution containing one or more amines, particularly an aqueous solution containing a silane and one or more amines, enhances the tensile strengths of foundry molds and cores produced therefrom relative to those obtained with untreated reclaimed sand. Methods for producing foundry cores and molds which incorporate such a treatment process are also provided by this invention, as are raw batch formulations.

Abstract: The present invention provides a binder solution having a low solids level which provides improved tensile properties when used with reclaimed sand. This binder solution comprises an alkaline phenolic resin which is cured at ambient temperature with an ester-functional curing agent. Also provided by this invention are raw batch formulations comprising sand, a binder solution having a low solids level, and a curing agent. These raw batch formulations include embodiments wherein the low solids levels are obtained by the separate addition of a solvent. The methods for producing foundry molds and cores of this invention included those procedures wherein dilution water is used to reduce the solids contents of conventional, relatively high solids content binder solutions.

Abstract: A hardener composition for alkaline phenolic resole resin binders which comprises a solution of a benzylic ether resole resin in an ester. Binder compositions comprising this hardener with alkaline phenolic resole resins are further provided as are foundry molding compositions and methods for making foundry cores and molds using the molding compositions.

Abstract: A hardener composition for alkaline phenolic resole resin binders which comprises a solution of a benzylic ether resole resin in an ester. Binder compositons comprising this hardener with alkaline phenolic resole resins are further provided as are foundry molding compositions and methods for making foundry cores and molds using the molding compositions.