Process for core removal from molded products

Abstract

A method of removing a core from a molded product in which the core is formed of a particulate inert material, such as .[.sand-bound.]. .Iadd.sand, bound .Iaddend.together by a cured binder of a water soluble carbohydrate alone or mixed with a silicate is disclosed. The silicate is preferably an alkali earth metal silicate, preferably sodium silicate, and the carbohydrate is preferably a saccharide or starch. The binder is cured by heat. The core and molded product are exposed to water, preferably heated water in a bath or steam, to rapidly disintegrate the core and remove it from the molded product.

We claim: 
     
       1. A method of removing a molding core from a molded product wherein said core comprises a particulate inert material which is formed into a discrete configuration conforming to the configuration of at least a portion of the molded product and the particulate inert material is bound in said configuration by a .Iadd.heat .Iaddend.cured binder comprising .Iadd.a silicate salt and .Iaddend.a water soluble carbohydrate, said method comprising exposing said bound core with said .[.water soluble carbohydrate.]. .Iadd.binder .Iaddend.therein and said molded product to water after the product has been molded to disintegrate and remove the core from the molded product. .[.2. The method of claim 1, wherein said 
     
     
        binder also includes a silicate..].3. The method of claim .[.2.]. .Iadd.1.Iaddend., wherein said silicate .Iadd.salt .Iaddend.is an alkali 
     
     
        earth metal silicate. 4. The method of claim 3, wherein said silicate 
     
     
        .Iadd.salt .Iaddend.is sodium silicate. 5. The method of claim 1, wherein said water soluble carbohydrate is selected from the group consisting of 
     
     
        saccharides and starches. 6. The method of claim 5, wherein said saccharide is selected from the group consisting of dextrose and molasses. 
     
     
        . The method of claim 5, wherein said starch is corn starch. .[.8.  The method of claim 2, wherein said water soluble carbohydrate is selected 
     
     
        from the group consisting of saccharides and starches..].9. The method of claim 1, wherein the particulate inert material is selected from the group consisting of sand, metal shot, plastic polymers, glass, alumina, clays 
     
     
        and mixtures thereof. .[.10.  The method of claim 2, wherein the particulate inert material is selected from the group consisting of sand, metal shot, plastic polymers, glass, alumina, clays and mixtures 
     
     
        thereof..].11. The method of claim 1, wherein said water is heated. 12. The method of claim 11, wherein the heated water has a temperature of 
     
     
        less than about 100° C. 13. The method of claim 1, wherein said 
     
     
        water is steam. 14. The method of claim 1, wherein the core and molded product are immersed in a bath of said water to disintegrate and remove 
     
     
        the core. 15. The method of claim 1, wherein said molded product is formed of a material selected from the group consisting of plastics and metals. 
     
     
        .[.16.  The method of claim 2, wherein said molded product is formed of a 
     
     
        material selected from the group consisting of plastics and metals..].17. The method of claim .[.16.]. .Iadd.15.Iaddend., wherein said silicate salt is sodium silicate, said water soluble carbohydrate is selected from the group consisting of saccharides and starches, and wherein the core and molded product are immersed in a bath of heated water 
     
     
        to disintegrate and remove the core. 18. The method of claim 17, wherein the particulate inert material is selected from the group consisting of sand, metal shot, plastic polymers, glass, alumina, clays and mixtures thereof. .[.19. The method of claim 1, wherein said binder is cured by 
     
     
        heating..].20. The method of claim .[.19.]. .Iadd.1.Iaddend., wherein said .[.heating.]. .Iadd.binder .Iaddend.is .Iadd.heat cured .Iaddend.by microwave energy. .[.21. The method of claim 2, wherein said binder is 
     
     
        cured by heating..]..[.22.  The method of claim 21, wherein said heating 
     
     
        is by microwave energy..]..[.23.  The method of claim 5, wherein said 
     
     
        binder is cure by heating..].24. The method of claim .[.23.]. .Iadd.5.Iaddend., wherein said .[.heating.]. .Iadd.binder .Iaddend.is .Iadd.heat cured .Iaddend.by microwave energy. .[.25. The method of claim 
     
     
        9, wherein said binder is cured by heating..].26. The method of claim .[.25.]. .Iadd.9.Iaddend., wherein said .[.heating.]. .Iadd.binder .Iaddend.is .Iadd.heat cured .Iaddend.by microwave energy. .[.27. The 
     
     
        method of claim 11, wherein said binder is cured by heating..].28. The method of claim .[.27.]. .Iadd.11.Iaddend., wherein said .[.heating.]. .Iadd.binder .Iaddend.is .Iadd.heat cured .Iaddend.by microwave energy. .[.29. The method of claim 18, wherein said binder is cured by 
     
     
        heating..]. 0. The method of claim .[.29.]. .Iadd.18.Iaddend., wherein said .[.heating.]. .Iadd.binder .Iaddend.is .Iadd.heat cured .Iaddend.by microwave energy.