The present invention relates primarily to a mixture that is suitable for use in the no-bake process for producing cores and molds for the foundry industry, and a reaction mixture comprising said mixture and an acid hardener (i.e. an acid catalyst). The present invention further relates to a method of producing a mixture according to the invention and a method of producing a mold or a core. The invention also relates to a mold or a core for producing metal objects and a kit comprising a mixture according to the invention and certain acid hardeners. The invention further relates to the use of a mixture according to the invention as cold-setting binder and the use of said mixtures or reaction mixtures in a no-bake process for producing metal objects.

The present invention is a granular material that can be well recoated regardless of the type of the granular material, and enables a refractory aggregate in an unprinted portion to be used without any regeneration process, in the manufacture of a three-dimensional laminated and shaped mold. This granular material is a granular material for use in three-dimensional laminated mold shaping, and obtained by adding a material that causes a hydration reaction having a moisture absorbing function and generates a catalytic effect to a coating material mixed with or coated with an acid as a catalyst which activates and hardens an organic binder for binding the granular material.

The present invention relates to a binder composition for making self-hardening foundry molds that is capable of improving the hardening speed of the molds and the strength of the molds, and is excellent in storage stability; and a method for producing a foundry mold, using this composition. The binder composition for making self-hardening foundry molds of the present invention is a binder composition for making self-hardening foundry molds, comprising a furan resin and an ion compound, wherein the ion compound contains at least one anion selected from the group consisting of a hydrogensulfite ion, a sulfite ion, a pyrosulfite ion, a thiosulfate ion, a thionate ion, and a dithionite ion; the content of the anion is from 0.006 to 0.60 parts by weight for 100 parts by weight of the furan resin; and the composition has a pH of 6 or less at 25 C.

A binder composition for making foundry molds, comprising an acid-hardening resin, one or more 5-position-substituted-furfural compounds selected from the group consisting of 5-hydroxymethylfurfural and 5-acetoxymethylfurfural, and one or more compounds selected from the group consisting of urea and derivatives of urea, wherein the content of the 5-position-substituted-furfural compound(s) by percentage is from 1 to 60% by weight of the binder composition. The content of the compound(s) by percentage selected from the group consisting of urea and derivatives of urea is preferably from 0.3 to 10% by weight of the binder composition.

In order to well perform recoating regardless of the type of granular material and reuse a refractory aggregate in an unprinted portion without any regeneration process in the manufacture of a three-dimensional lamination-shaped mold, this invention provides a granular material for use in shaping a three-dimensional laminated mold, which is coated with an acid as a catalyst which activates and cures an organic binder for binding the granular material. The acid contains at least one of sulfuric acid, phosphoric acid, a sulfonic acid and a carboxylic acid, and is one of a mixture of sulfuric acid and another acid, phosphoric acid only, a mixture of phosphoric acid and another acid, sulfonic acid only, a mixture of sulfonic acid and another acid and a mixture of a carboxylic acid and another acid.

What is described is the use of a composition containing one or more formaldehyde scavengers for production of a coating on a main body of a mold or core for metal casting that emits formaldehyde when heated, wherein the coating forms a surface of the mold or core that comes into contact with a metal melt in the casting operation.

Boric acid is used as an adjuvant for the liquid catalyst used to cure furan-based binder systems for forming a foundry mold in a warm box process. The binder system comprises furfuryl alcohol, a furan resin, and a furan monomer or oligomer containing at least two terminal hydroxymethyl groups. The binder system also comprises a latent acid curing catalyst and the boric acid. The boric acid improves tensile strength of the foundry mix as well as through cure of the binder.

The subject of the invention is a process for the layer-by-layer production of a building structure using furfuryl alcohol and novolaks as a viscosity modifier, building structures produced in this way, such as cores or molds for metal casting and their use, as well as a binder and a kit comprising binder and, separately therefrom, hardener.