Provided is casting sand including sand and a solid acid catalyst mixed with the sand.

A method for producing a sand mold includes mixing artificial sand with a furan resin composition including a furan resin precursor, preparing molding sand having the artificial sand and a surface-modified layer containing a resin cured product covering the artificial sand and including a curing agent attached to the surface-modified layer by mixing the curing agent including xylene sulfonic acid with the artificial sand with which the furan resin composition is mixed, and curing the furan resin composition, after mixing the artificial sand with the furan resin composition, and curing an added portion of the binder in the molding sand by adding the binder to the molding sand. In the step of curing the added portion of the binder, the curing agent for curing the furan resin composition is used also as a curing agent for curing the binder.

The present invention relates to a method for the layer-by-layer production of a cured three- dimensional shaped body, wherein the method comprises at least: (i) providing a binder comprising at least the following components: a) monomeric furfuryl alcohol and optionally a resin component comprising at least a furan resin, wherein about 60% by weight to 100% by weight of monomeric furfuryl alcohol, based on the sum of monomeric furfuryl alcohol and resin component are present in the binder, and b) a hardener component selected from methanesulfonic acid, benzenesulfonic acid, and mixtures thereof, (ii) providing a layer of a refractory molding material to provide a molding material layer, (iii) selectively applying a component a) or b) of the binder separately from the refractory molding material to at least a part of the molding material layer, (iv) applying the other component of the binder separately from the component mentioned in step (iii), wherein step (iv) can be carried out before or after step (iii), or step (iv) can be combined with step (ii), and (v) optionally repeating steps (ii), (iii), and (iv) once or several times. Shaped bodies obtainable thereby as well as their use are disclosed as well.

The invention relates to a method for producing three-dimensionally layered shaped bodies by means of layer-by-layer construction using a resin component which contains at least one furane resin, and more than 5% by weight and less than 50% by weight monomer furfuryl alcohol, and an acid. The shaped bodies produced in this manner are suitable inter alia as casting molds and casting cores for metal casting.

A method for additive manufacturing is provided, including: mixing a hardener with a sand material, so that the hardener is evenly coated on a surface of the sand material, and then spraying a binder through a nozzle, reacting the binder sprayed through the nozzle with the surface of the sand material evenly coated with the hardener to harden a sand mold. Therefore, the problem of nozzle clogging may be overcome, and a solid with a particle size of less than 0.6 μm may be obtained by the additive manufacturing. In addition, the hardening speed can be adjusted according to the size of the sand mold. Compared with a general sand mold product, the hardening speed may be increased and the storage life of the binder may be prolonged when the sand mold has a large size.

The present invention relates to a mold material mixture for producing moldings for the foundry industry, in particular for producing foundry molds, cores or feeders for the foundry industry, which comprises A) one or more pourable, refractory fillers, B) a binder system comprising i) formaldehyde, a formaldehyde donor and/or precondensates of formaldehyde and ii) an amino acid. The present invention additionally relates to the use of amino acids in a mold material mixture for producing moldings for the foundry industry or for producing moldings for the foundry industry, a process for producing a mold material mixture and a process for producing a molding for the foundry industry.

A method for producing a sand mold includes mixing artificial sand with a furan resin composition including a furan resin precursor, preparing molding sand having the artificial sand and a surface-modified layer containing a resin cured product covering the artificial sand and including a curing agent attached to the surface-modified layer by mixing the curing agent including xylene sulfonic acid with the artificial sand with which the furan resin composition is mixed, and curing the furan resin composition, after mixing the artificial sand with the furan resin composition, and curing an added portion of the binder in the molding sand by adding the binder to the molding sand. In the step of curing the added portion of the binder, the curing agent for curing the furan resin composition is used also as a curing agent for curing the binder.

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.

The subject matter of the invention is mold material mixtures for producing molds or cores for metal casting, consisting of at least one refractory base mold material, a binder and an additive based on factice. The invention also relates to a component system, a method for producing molds and cores using the mold material mixtures or the component system respectively, and to molds and cores produced by said method.

The invention relates to a method of producing an article selected from the group consisting of casting mold, core, feeder and molding compound for production of part of a casting mold, core or feeder, comprising the following steps: (S1) producing or providing in the foundry: a first component (A), comprising a first binder component (b1) of a binder system and an amount of a first mold base material and, spatially separated therefrom, a second component (B), comprising a second binder component (b2) of the binder system and an amount of a second mold base material wherein the first binder component (b1) and the second binder component (b2) are suitable for chemical reaction with one another and for curing of a mixture of the first component (A) and the second component (B), (S2) mixing by contacting the first component (A) and the second component (B) in a particular mass ratio, so as to result in a self-curing molding compound.