JP2021041459A - Molding binder composition - Google Patents

Abstract

To provide a molding binder composition that allows for improving the productivity of flask release work after casting by improving the collapsibility of a mold, or reducing the strength of residual mold pressure.SOLUTION: A molding binder composition contains phenol resin and a cyclic ketal compound with a carbon number of 5 or more having a hydroxyl group.SELECTED DRAWING: None

Description

The present invention relates to a binder composition for molding.

A molding method is known in which a phenol resin is used as a binder and the phenol resin is cured with an organic ester or carbon dioxide gas having excellent safety.

The mold is required to have strength that can withstand handling and casting of molten metal, but on the other hand, high disintegration property is required in order to easily take out the casting after casting and shorten the time for unframe work.

Organic binders are said to have relatively good disintegration because the binder is thermally decomposed by the heat of casting, but phenolic resins are so-called secondary curing by heating at about 100 to 300 ° C. Since the mold strength is increased, the disintegration property of the portion heated in that range at the time of casting is reduced.

Japanese Unexamined Patent Publication No. 7-148546 Japanese Unexamined Patent Publication No. 10-1903033 Japanese Unexamined Patent Publication No. 9-57391

In response to the above problems, Patent Documents 1 to 3 propose a method of adding a metal salt compound or the like.

However, the conventional binder composition for molding is insufficient in terms of mold disintegration, and there is room for improvement.

INDUSTRIAL APPLICABILITY The present invention is a binder for mold molding, which can improve the disintegration property of a mold, that is, reduce the residual strength without lowering the mold strength at the time of mold molding, and improve the productivity of unframe work after casting. The composition is provided.

The binder composition for molding of the present invention contains a phenol resin and a cyclic ketal compound having a hydroxyl group and having 5 or more carbon atoms.

According to the present invention, a binder composition for mold molding, for mold molding, which can improve the disintegration property of the mold and improve the productivity of unframe work after casting without lowering the mold strength at the time of mold molding. It is possible to provide a composition, an additive for molding, and a method for producing a mold.

<Caking agent composition for molding>
The binder composition for molding of the present embodiment (hereinafter, also referred to as a binder composition) is a phenol resin and a cyclic ketal compound having a hydroxyl group and having 5 or more carbon atoms (hereinafter, also referred to as a cyclic ketal compound). It is a binder composition for molding which contains. According to the binder composition of the present embodiment, it is possible to suppress the improvement of the residual mold compressive strength of the mold after casting without lowering the mold strength at the time of mold molding, so that the disintegration property of the mold is improved. However, the productivity of unframe work of the mold after casting can be improved. Since the disintegration property of the mold is improved, lumps that cannot be broken into single sand particles generated during the crushing process of the casting sand are reduced, and the amount of waste is reduced. Further, since the residual resin during the regeneration of the cast sand is easily removed, the LOI (burning weight loss) of the recycled sand is reduced, and the strength of the mold using the recycled sand is improved. Further, since there is almost no secondary hardening due to heating, in the field of cast steel having a large solidification shrinkage, the mold can follow the solidification shrinkage of the casting after casting, so that it is considered that crack defects during the shrinkage of the casting are also reduced. The reason for exhibiting such an effect is not clear, but it is considered as follows.

When the composition for a mold contains a phenol resin, in general, the phenol resin undergoes secondary curing when the mold is heated by casting or the like, and the compressive strength of the mold is improved, so that the mold is less likely to collapse. However, the cyclic ketal compound having a hydroxyl group and having 5 or more carbon atoms contained in the binder composition of the present embodiment is appropriately compatible with the phenol resin in order to have an appropriate hydrophobicity, and the reaction site of the phenol resin. It is considered that the improvement of the residual mold compressive strength can be suppressed and the disintegration property of the mold can be improved by appropriately coordinating with the hydroxyl group of the phenol and suppressing the secondary curing of the phenol resin.

[Phenol resin]
The phenol resin is generally obtained by polycondensing a phenol compound and an aldehyde compound under alkaline conditions. Among these, phenol compounds include phenol, bisphenol A, bisphenol F, cresol, 3,5-xylenol, resorcinol, catechol, nonylphenol, p-tert-butylphenol, isopropenylphenol, phenylphenol, and other substituted phenols. , And a mixture of various phenolic compounds such as cashew nut shell liquid can be used by mixing one kind or two or more kinds. As the aldehyde compound, formaldehyde, acetaldehyde, furfural, glyoxal and the like can be used alone or in admixture of two or more. These compounds can be used as an aqueous solution if necessary. In addition, monomers that can be condensed with aldehyde compounds such as urea, melamine, and cyclohexanone, monovalent aliphatic alcohol compounds such as methanol, ethanol, isopropyl alcohol, normal propyl alcohol, and butyl alcohol, and water-soluble polymers are added to these. Polyacrylate, cellulose derivative polymer, polyvinyl alcohol, lignin derivative, etc. may be mixed.

Examples of the alkali catalyst used in the synthesis of the phenol resin include hydroxides of alkali metals such as LiOH, NaOH and KOH, and NaOH and KOH are particularly preferable. Further, these alkaline catalysts may be mixed and used.

The phenol resin is preferably an aqueous solution, and the solid content mass (solid mass after drying at 105 ° C. for 3 hours) is preferably 30% by mass or more, more preferably 50% by mass or more, from the viewpoint of improving the mold strength. preferable. The solid content mass of the phenol resin aqueous solution is preferably 85% by mass or less, more preferably 75% by mass or less, from the viewpoint of improving the mold strength and the workability. Further, the solid content mass of the phenol resin aqueous solution is preferably 30 to 80% by mass, more preferably 50 to 75% by mass, from the viewpoint of improving the mold strength and the workability.

The weight average molecular weight (Mw) of the phenol resin is preferably 500 or more, more preferably 800 or more, still more preferably 1200 or more, from the viewpoint of improving the template strength. The weight average molecular weight (Mw) of the phenol resin is preferably 8000 or less, more preferably 5000 or less, still more preferably 3000 or less, from the viewpoint of improving the mold strength and the workability. The weight average molecular weight (Mw) of the phenol resin is preferably 500 to 8000, more preferably 800 to 5000, and even more preferably 1200 to 3000 from the viewpoint of improving the mold strength and the workability. The weight average molecular weight of the phenol resin is measured by the method described in Examples.

The content of the phenol resin in the binder composition is preferably 10% by mass or more, more preferably 25% by mass or more, still more preferably 40% by mass or more, from the viewpoint of improving the mold strength. The content of the phenol resin in the binder composition is preferably 95% by mass or less, more preferably 80% by mass or less, and more preferably 70% by mass, from the viewpoint of improving the mold strength and the workability. The following is further preferable, and 60% by mass or less is even more preferable. The content of the phenol resin in the binder composition is preferably 10 to 95% by mass, more preferably 25 to 80% by mass, from the viewpoint of improving the mold strength and the workability. 25 to 70% by mass is further preferable, and 40 to 60% by mass is even more preferable.

[Cyclic ketal compound having a hydroxyl group and having 5 or more carbon atoms]
The cyclic ketal compound has 5 or more carbon atoms, preferably 6 or more carbon atoms from the viewpoint of improving the disintegration property of the mold after casting. From the same viewpoint, the cyclic ketal compound has a carbon number of preferably 20 or less, more preferably 14 or less, still more preferably 10 or less, and even more preferably 8 or less.

The molecular weight of the cyclic ketal compound is preferably 110 or more, more preferably 115 or more, still more preferably 130 or more, from the viewpoint of improving the disintegration property of the mold after casting. From the same viewpoint, the molecular weight of the cyclic ketal compound is preferably 200 or less, more preferably 170 or less, still more preferably 150 or less, still more preferably 140 or less.

The number of cyclic ketal structures in one molecule of the cyclic ketal compound is preferably 2 or less, and more preferably 1 from the viewpoint of improving the disintegration property of the mold after casting.

The number of hydroxyl groups in one molecule of the cyclic ketal compound is preferably 4 or less, more preferably 3 or less, still more preferably 2 or less, from the viewpoint of improving the disintegration property of the mold after casting. Even more preferably, it is 1.

Further, the cyclic ketal compound has one cyclic ketal structure and two hydroxyl groups, and one cyclic ketal structure and one hydroxyl group from the viewpoint of improving the disintegration property of the mold after casting. A compound having one is preferable, and a compound having one cyclic ketal structure and one hydroxyl group is more preferable.

The cyclic ketal compound is obtained by reacting a trihydric or higher polyhydric alcohol with one or more selected from aldehydes and ketones.

The valence of the polyhydric alcohol is preferably trivalent or higher, preferably octavalent or lower, more preferably hexavalent or lower, still more preferably, from the viewpoint of improving the disintegration property of the mold after casting and from the viewpoint of availability. Is less than or equal to 4 valences.

Examples of trihydric or higher polyhydric alcohols include glycerin, trimethylolethane, trimethylolpropane, erythritol, pentaerythritol, xylitol, sorbitol, mannitol, dipentaerythritol and the like.

The carbon number of the aldehyde and the ketone is preferably 1 or more, more preferably 2 or more, and preferably 25 or less, from the viewpoint of improving the disintegration property of the mold after casting and from the viewpoint of availability. It is preferably 10 or less, more preferably 5 or less, even more preferably 4 or less, and even more preferably 3 or less.

Examples of aldehydes and ketones include formaldehyde, acetaldehyde, acetone, propionaldehyde, methyl ethyl ketone, butyraldehyde, barrel aldehyde, diethyl ketone and the like.

The cyclic ketal compound is preferably a compound represented by the following general formula (1) from the viewpoint of improving the disintegration property of the mold after casting.

(In the above general formula (1), R1 and R2 each represent hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, and R3 and R4 represent hydrogen or -CH ₂ OH groups, respectively. However, R3 and R4 simultaneously represent hydrogen or a -CH 2 OH group. Not hydrogen.)

The cyclic ketal compound is more preferably a compound represented by the following general formula (2) from the viewpoint of improving the disintegration property of the mold after casting.

(In the above general formula (2), R1 and R2 represent hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, respectively. However, R1 and R2 are not hydrogen at the same time.)

The hydrocarbon groups of R1 and R2 in the general formulas (1) and (2) are preferably alkyl groups from the viewpoint of improving the disintegration property of the mold after casting and from the viewpoint of availability.

The carbon numbers of R1 and R2 in the general formulas (1) and (2) are preferably 1 to 4, more preferably 1 to 4, from the viewpoint of improving the disintegration property of the mold after casting and from the viewpoint of availability. It is 3, more preferably 1-2, and even more preferably 2.

The hydrocarbon groups of R1 and R2 in the general formulas (1) and (2) are methyl group, ethyl group, n-propyl group, i from the viewpoint of improving the disintegration property of the mold after casting and from the viewpoint of availability. -Propyl group and n-butyl group are preferable, methyl group and ethyl group are more preferable, and methyl group is further preferable.

At least one of R1 and R2 in the general formulas (1) and (2) is preferably an alkyl group from the viewpoint of improving the disintegration property of the mold after casting and from the viewpoint of availability, and both are alkyl groups. Is more preferable.

In R1 and R2 in the general formulas (1) and (2), R1 is a methyl group and R2 is a methyl group, and R1 is a methyl group and R2 from the viewpoint of improving the disintegration property of the mold after casting and from the viewpoint of availability. Is an ethyl group, R1 is a methyl group and R2 is a hydrogen, R1 is an ethyl group and R2 is an ethyl group, R1 is a methyl group and R2 is a methyl group, R1 is a methyl group and R2 is an ethyl group, and R1 is. It is more preferable that the methyl group and R2 are hydrogen, R1 is a methyl group and R2 is a methyl group, R1 is a methyl group and R2 is hydrogen, and R1 is a methyl group and R2 is a methyl group. Is even more preferable.

_{R3 and R4 in the general formula (2) are preferably hydrogen in R1 and -CH 2} OH group in R2 from the viewpoint of improving the disintegration property of the mold after casting and from the viewpoint of availability. That is, the compound represented by the general formula (1) is preferably the compound represented by the general formula (2).

The content of the compound represented by the general formula (1) or the general formula (2) in the cyclic ketal compound is preferably 80% by mass or more from the viewpoint of improving the disintegration property of the mold after casting and from the viewpoint of availability. , More preferably 90% by mass or more, still more preferably 95% by mass or more, still more preferably 100% by mass.

The content of the cyclic ketal compound in the binder composition is preferably 0.2% by mass or more, more preferably 0, from the viewpoint of improving the disintegration property of the mold after casting and improving the mold strength. It is 5.5% by mass or more, more preferably 1% by mass or more, further preferably 2% by mass or more, still more preferably 4% by mass or more, still more preferably 8% by mass or more, and from the same viewpoint, it is preferable. It is 30% by mass or less, more preferably 25% by mass or less, still more preferably 20% by mass or less. The content of the cyclic ketal compound in the binder composition is preferably 0.2 to 30% by mass, more preferably 0.2 to 30% by mass, from the viewpoint of improving the disintegration property of the mold after casting and improving the mold strength. 0.5 to 30% by mass, more preferably 1 to 25% by mass, still more preferably 1 to 20% by mass, still more preferably 2 to 20% by mass, still more preferably 4 to 20% by mass, still more preferably. It is 8 to 20% by mass.

The content of the cyclic ketal compound with respect to 100 parts by mass of the phenol resin is preferably 0.5 parts by mass or more, more preferably 1 part by mass, from the viewpoint of improving the disintegration property of the mold after casting and improving the mold strength. Parts or more, more preferably 2 parts by mass or more, still more preferably 4 parts by mass or more, still more preferably 8 parts by mass or more, still more preferably 16 parts by mass or more, and from the same viewpoint, preferably 65 parts by mass or more. Hereinafter, it is more preferably 50 parts by mass or less, still more preferably 40 parts by mass or less. The content of the cyclic ketal compound with respect to 100 parts by mass of the phenol resin is preferably 0.5 to 65 parts by mass, more preferably 0, from the viewpoint of improving the disintegration property of the mold after casting and improving the mold strength. .5 to 50 parts by mass, more preferably 0.5 to 40 parts by mass, still more preferably 1 to 40 parts by mass, still more preferably 2 to 40 parts by mass, still more preferably 4 to 40 parts by mass, still more. It is preferably 8 to 40 parts by mass, and even more preferably 16 to 40 parts by mass.

[Other ingredients]
The binder composition may further contain additives such as water, alcohol, a silane coupling agent, an oxyanion compound, and a surfactant to the extent that the effects of the present embodiment are not impaired.

[alcohol]
The binder composition preferably contains alcohol from the viewpoint of improving the template strength. As the alcohol, one or more selected from polyhydric alcohols, glycol ethers, alicyclic glycol compounds and aromatic alcohols are preferable. Examples of the alcohol include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polyhydric alcohols such as 2,2-dimethyl-1,3-propanediol and glycerin, and ethylene glycol monomethyl. Ether, ethylene glycol monoethyl ether, ethylene glycol mono n-propyl ether, ethylene glycol monoisopropyl ether, ethylene glycol mono n-butyl ether, ethylene glycol monoisobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol Monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, propylene glycol monomethyl ether, ethylene glycol monophenyl ether, diethylene glycol monophenyl ether, triethylene glycol monophenyl ether, tetraethylene glycol monophenyl ether and dipropylene glycol monomethyl Glycol ethers such as ethers, alicyclic glycol compounds such as cyclohexanediol and cyclohexanedimethanol, phenoxyalcohols such as 2-phenoxyethanol, 2-phenoxypropanol, 1-phenoxy-2-propanol and aromatic alcohols such as benzyl alcohol can be mentioned. Be done. When carbon dioxide gas is used as the curing agent, one or more selected from glycol ether and aromatic alcohol is preferable from the viewpoint of improving the template strength, and it is selected from triethylene glycol monoethyl ether, diethylene glycol monoethyl ether and 2-phenoxyethanol. One or more are more preferable.

The content of one or more selected from the polyhydric alcohol, glycol ether, alicyclic glycol compound and aromatic compound alcohol in the alcohol is preferably 80% by mass from the viewpoint of improving the disintegration property of the mold after casting. As mentioned above, it is more preferably 90% by mass or more, further preferably 95% by mass or more, and even more preferably 100% by mass.

The content of the alcohol in the binder composition is preferably 0.5% by mass or more, more preferably 1% by mass or more, still more preferably 2% by mass or more, still more, from the viewpoint of improving the template strength. It is preferably 4% by mass or more, preferably 15% by mass or less, more preferably 12% by mass or less, still more preferably 10% by mass, from the viewpoint of improving the disintegration property of the mold after casting and improving the mold strength. Below, it is even more preferably 9% by mass or less, even more preferably 7% by mass or less, and even more preferably 6% by mass or less. The content of the alcohol in the binder composition is preferably 0.5 to 15% by mass, more preferably 1 to 1 from the viewpoint of improving the disintegration property of the mold after casting and improving the mold strength. It is 12% by mass, more preferably 2 to 10% by mass, still more preferably 2 to 9% by mass, still more preferably 2 to 7% by mass, still more preferably 4 to 6% by mass.

The content of the alcohol with respect to 100 parts by mass of the phenol resin is preferably 1 part by mass or more, more preferably 2 parts by mass or more, still more preferably 4 parts by mass or more, still more preferably 8 from the viewpoint of improving the template strength. It is more than 40 parts by mass, preferably 40 parts by mass or less, more preferably 35 parts by mass or less, still more preferably 20 parts by mass or less, from the viewpoint of improving the disintegration property of the mold after casting and improving the mold strength. It is more preferably 18 parts by mass or less, and even more preferably 13 parts by mass or less. The content of the alcohol with respect to 100 parts by mass of the phenol resin is preferably 1 to 40 parts by mass, more preferably 2 to 35 parts by mass, from the viewpoint of improving the disintegration property of the mold after casting and improving the mold strength. , More preferably 4 to 35 parts by mass, even more preferably 4 to 20 parts by mass, even more preferably 4 to 18 parts by mass, even more preferably 4 to 13 parts by mass, still more preferably 8 to 13 parts by mass. is there.

The content of the cyclic ketal compound in the binder composition containing alcohol is preferably 0.2% by mass or more from the viewpoint of improving the disintegration property of the mold after casting and improving the mold strength. More preferably 0.5% by mass or more, further preferably 1% by mass or more, still more preferably 2% by mass or more, still more preferably 4% by mass or more, and from the same viewpoint, preferably 18% by mass or less. It is more preferably 15% by mass or less, further preferably 10% by mass or less, and even more preferably 7% by mass or less. The content of the cyclic ketal compound in the binder composition is preferably 0.2 to 18% by mass, more preferably 0.2 to 18% by mass, from the viewpoint of improving the disintegration property of the mold after casting and improving the mold strength. 0.2 to 15% by mass, more preferably 0.2 to 10% by mass, still more preferably 1 to 10% by mass, still more preferably 2 to 10% by mass, still more preferably 4 to 10% by mass, and more. More preferably, it is 4 to 7% by mass.

In the binder composition containing alcohol, the content of the cyclic ketal compound with respect to 100 parts by mass of the phenol resin is preferably from the viewpoint of improving the disintegration property of the mold after casting and improving the mold strength. It is 0.5 parts by mass or more, more preferably 2 parts by mass or more, further preferably 4 parts by mass or more, still more preferably 8 parts by mass or more, and from the same viewpoint, preferably 30 parts by mass or less, more preferably 25 parts by mass or more. It is less than or equal to parts by mass, more preferably 18 parts by mass or less, and even more preferably 14 parts by mass or less. In the binder composition containing alcohol, the content of the cyclic ketal compound with respect to 100 parts by mass of the phenol resin is preferably from the viewpoint of improving the disintegration property of the mold after casting and improving the mold strength. 0.5 to 30 parts by mass, more preferably 0.5 to 25 parts by mass, still more preferably 0.5 to 20 parts by mass, still more preferably 2 to 20 parts by mass, still more preferably 4 to 20 parts by mass. It is even more preferably 8 to 18 parts by mass, and even more preferably 8 to 14 parts by mass.

The total content of the cyclic ketal compound and the alcohol in the binder composition is preferably 1% by mass or more, more preferably from the viewpoint of improving the disintegration property of the mold after casting and improving the mold strength. Is 2% by mass or more, more preferably 4% by mass or more, still more preferably 8% by mass or more, and preferably 20% by mass from the viewpoint of improving the disintegration property of the mold after casting and improving the mold strength. Hereinafter, it is more preferably 15% by mass or less, still more preferably 12% by mass or less. The total content of the cyclic ketal compound and the alcohol in the binder composition is preferably 1 to 20% by mass, from the viewpoint of improving the disintegration property of the mold after casting and improving the mold strength. It is preferably 2 to 20% by mass, more preferably 4 to 20% by mass, still more preferably 4 to 15% by mass, and even more preferably 8 to 12% by mass.

The total content of the cyclic ketal compound and the alcohol with respect to 100 parts by mass of the phenol resin is preferably 2 parts by mass or more, more preferably 2 parts by mass or more from the viewpoint of improving the disintegration property of the mold after casting and improving the mold strength. It is 4 parts by mass or more, more preferably 8 parts by mass or more, still more preferably 16 parts by mass or more, and preferably 40 parts by mass or less from the viewpoint of improving the disintegration property of the mold after casting and improving the mold strength. , More preferably 35 parts by mass or less, still more preferably 25 parts by mass or less. The total content of the cyclic ketal compound and the alcohol with respect to 100 parts by mass of the phenol resin is preferably 2 to 40 parts by mass, more preferably from the viewpoint of improving the disintegration property of the mold after casting and improving the mold strength. Is 4 to 40 parts by mass, more preferably 4 to 35 parts by mass, still more preferably 8 to 35 parts by mass, and even more preferably 16 to 25 parts by mass.

The ratio of the content of the cyclic ketal compound to the total content of the alcohol and the cyclic ketal compound is preferably 0.1 or more, more preferably 0.2 or more, from the viewpoint of improving the disintegration property of the mold after casting. , More preferably 0.3 or more, still more preferably 0.4 or more, and from the viewpoint of improving the mold strength, preferably 0.8 or less, more preferably 0.7 or less, still more preferably 0.6 or less. Is. The ratio of the content of the cyclic ketal compound to the total content of the alcohol and the cyclic ketal compound is preferably 0 from the viewpoint of improving the disintegration property of the mold after casting and improving the mold strength. .1 to 0.8, more preferably 0.2 to 0.8, still more preferably 0.4 to 0.6, and preferably 0.4 to 0.4 from the viewpoint of improving the disintegration property of the mold after casting. It is 0.8, preferably 0.2 to 0.7, and more preferably 0.2 to 0.6 from the viewpoint of improving the mold strength.

[Silane coupling agent]
The binder composition preferably contains a silane coupling agent from the viewpoint of improving the mold strength. Examples of the silane coupling agent include γ- (2-amino) propylmethyldimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and N-β-. (Aminoethyl) γ-aminopropylmethyldimethoxysilane and the like can be mentioned. The content of the silane coupling agent in the binder composition is preferably 0.1 to 5% by mass, more preferably 0.3 to 1% by mass, from the viewpoint of improving the template strength.

[Oxyanion compound]
When the binder composition is cured with carbon dioxide gas, it is preferable to contain an oxyanion compound from the viewpoint of improving the mold strength and the curing rate of the mold. This is because it is considered that the oxyanion compound forms an ionomer only after absorbing carbon dioxide gas to polymerize the water-soluble phenol resin. Examples of the oxyanion compound include boric acid and borate, aluminate, stannate and the like. Examples of the borate include sodium tetraborate tetrahydrate (borax), potassium tetraborate pentahydrate, sodium metaborate, sodium pentaborate, potassium pentaborate and the like. Examples of the aluminate include sodium aluminate. The content of the oxyanion compound in the binder composition is preferably 0.1 to 30% by mass, more preferably 0.5 to 30% by mass, from the viewpoint of improving the mold strength and the curing rate of the mold. It is 12% by mass, more preferably 1 to 8% by mass.

<Molding method>
In the mold manufacturing method of the present embodiment, the mold can be manufactured by using the conventional mold manufacturing process as it is. As a preferred method for producing a mold, at least a mixing step of mixing the fire-resistant particles and the binder composition to obtain a composition for molding, and packing the composition for molding into a mold for the molding. Examples thereof include a method for producing a mold having a curing step of curing the composition.

[Mixing process]
[Refractory particles]
As the refractory particles that can be used in the method for producing the mold of the present embodiment, conventionally known particles such as silica sand, chromate sand, zircon sand, olivine sand, alumina sand, mullite sand, synthetic mullite sand, and alumina ball sand are used. In addition, recycled sand obtained by recovering and regenerating used refractory particles can also be used. The refractory particles can be used alone or in combination of two or more.

The average particle size of the refractory particles is preferably more than 50 μm, more preferably 70 μm or more, further preferably 120 μm or more, still more preferably 150 μm or more, and from the same viewpoint, preferably 600 μm or less, more preferably 400 μm. Below, it is more preferably 300 μm or less, and even more preferably 250 μm or less. In this specification, the average particle size is measured by the method described in Examples.

As a method of mixing each raw material in the mixing step, a known general method can be used, for example, a method of adding each raw material by a batch mixer and kneading, or a method of supplying each raw material to a continuous mixer and kneading. There is a way to do it.

The ratio of the refractory particles to the binder composition can be appropriately set, but from the viewpoint of improving the mold strength and the viewpoint of economy, the refractory particles with respect to 1000 parts by mass of the binder composition. The content of is preferably 10 parts by mass or more, and preferably 100 parts by mass or less. Further, the phenol resin is preferably 5 parts by mass or more, and preferably 80 parts by mass or less with respect to 1000 parts by mass of the refractory particles.

In the mixing step, when the molding composition is obtained, the cyclic ketal compound may be further mixed separately from the binder composition. In that case, the content of the cyclic ketal compound in the molding composition is preferably in the range of the content of the cyclic ketal compound with respect to 100 parts by mass of the phenol resin.

It is also possible to obtain a molding composition by mixing a binder composition containing refractory particles and a phenol resin but not a cyclic ketal compound and the cyclic ketal compound. The blending amount of the cyclic ketal compound in this case is the same as the content described in the binder composition.

Further, the refractory particles, the phenol resin, the cyclic ketal compound and other components used in the binder composition can be separately mixed to obtain a molding composition. In this case, the content of the phenol resin is preferably 5 parts by mass or more, and preferably 80 parts by mass or less with respect to 1000 parts by mass of the refractory particles. The blending amount of the cyclic ketal compound and other components used in the binder composition is the same as the content described in the binder composition.

When the cyclic ketal compound is mixed separately from the binder composition as described above, the cyclic ketal compound is an additive for molding. The molding additive of the present embodiment contains a cyclic ketal compound having a hydroxyl group and having 5 or more carbon atoms. The mold molding additive can reduce the residual strength of the mold after casting, improve the disintegration property of the mold, and improve the productivity of the unframe work after casting. The preferred embodiment of the cyclic ketal compound in the mold molding additive of the present invention is the same as the preferred embodiment of the cyclic ketal compound in the molding binder composition.

[Curing process]
In the curing step, the molding composition is packed in a mold and the molding composition is cured. As a method for curing the molding composition, a known general method can be used. Examples of the method for curing the molding composition include a method of curing with a curing agent. Examples of the curing agent include organic ester compounds and carbon dioxide gas.

Examples of the organic ester compound include lactones having 3 to 10 carbon atoms, an organic ester derived from a monohydric or polyhydric alcohol having 1 to 10 carbon atoms and an organic carboxylic acid having 1 to 10 carbon atoms, or 1 to 8 carbon atoms. The alkylene carbonate of is used alone or in combination. In the self-hardening molding method, γ-butyrolactone, propion lactone, ε-caprolactone, ethyl formate, ethylene glycol diacetate, ethylene glycol monoacetate, triacetin, ethylene carbonate, propylene carbonate and the like are preferably used, and an organic ester is used. Methyl formate is preferably used in the gas curable molding method.

When an organic ester is used as the curing agent, the amount of the organic ester is 10 with respect to 100 parts by mass of the binder composition from the viewpoint of improving the template strength, improving the curing rate, and economically. It is preferably parts by mass or more, more preferably 15 parts by mass or more, preferably 35 parts by mass or less, and more preferably 30 parts by mass or less.

When an organic ester is used as the curing agent, the amount of the organic ester is 20 parts by mass or more with respect to 100 parts by mass of the phenol resin from the viewpoint of improving the mold strength, improving the curing rate, and economically. Preferably, 30 parts by mass or more is more preferable, 70 parts by mass or less is preferable, and 60 parts by mass or less is more preferable.

When using carbon dioxide as the curing agent, the flow rate of carbon dioxide, from the viewpoint of improving the mold strength, mold 100 cm ³ per preferably 0.2 L / min or more, more preferably 1L / min or more, economical efficiency from the point of view, the mold 100 cm ³ per preferably not more than 30L / min, more preferably 15L / min or less, more preferably 7L / min or less, still more preferably not more than 4L / min. The flow time of carbon dioxide gas is preferably 10 seconds or longer, more preferably 20 seconds or longer, further preferably 30 seconds or longer, and preferably 90 seconds or shorter, more preferably 90 seconds or longer, from the viewpoint of improving the mold strength. Is 70 seconds or less, more preferably 50 seconds or less. The temperature at the time of curing is preferably −5 ° C. or higher, more preferably 5 ° C. or higher, still more preferably 10 ° C. or higher from the viewpoint of improving the mold strength, and preferably 45 ° C. or lower from the viewpoint of economic efficiency. It is preferably 40 ° C. or lower, more preferably 35 ° C. or lower.

When carbon dioxide gas is used as the curing agent, the amount of carbon dioxide gas is 25 with respect to 100 parts by mass of the binder composition from the viewpoint of improving the mold strength, improving the curing rate, and economically. It is preferably parts by mass or more, more preferably 30 parts by mass or more, preferably 100 parts by mass or less, and more preferably 75 parts by mass or less.

When carbon dioxide gas is used as the curing agent, the amount of carbon dioxide gas is 50 parts by mass or more with respect to 100 parts by mass of the phenol resin from the viewpoint of improving the mold strength, improving the curing rate, and economically. Preferably, 60 parts by mass or more is more preferable, 200 parts by mass or less is preferable, and 150 parts by mass or less is more preferable.

<Composition for molding>
The molding composition of the present embodiment contains refractory particles and the binder composition. That is, the molding composition of the present embodiment contains refractory particles, a phenol resin, and the cyclic ketal compound.

The content of the binder composition is as described in the mixing step of the method for producing the mold with respect to the refractory particles.

The content of the phenol resin is as described in the mixing step of the method for producing the mold with respect to the refractory particles. The content of the cyclic ketal compound is as described in the binder composition with respect to the phenol resin.

[Inorganic particles]
The mold molding composition of the present embodiment preferably contains inorganic particles from the viewpoint of improving the disintegration property of the mold after casting. It is considered that the inorganic particles are present in the cured binder composition, and since the coefficient of thermal expansion of the inorganic particles is different from the coefficient of thermal expansion of the cured binder composition, it is considered that the decrease in residual strength after heating is promoted. Be done.

Examples of the inorganic particles include silica, mullite, kaolin, and fly ash.
The inorganic particles may be amorphous or crystalline.

The shape of the inorganic particles may be spherical, lumpy, amorphous, or the like, but is preferably spherical particles from the viewpoint of improving the disintegration property of the mold after casting and improving the mold strength.
The average particle size of the inorganic particles is preferably 0.05 μm or more, more preferably 0.1 μm or more, still more preferably 1 μm or more, still more preferably 2 μm or more, from the viewpoint of improving the disintegration property of the mold after casting. From the same viewpoint, it is preferably 50 μm or less, more preferably 25 μm or less, still more preferably 18 μm or less.

The content of the inorganic particles with respect to 100 parts by mass of the phenol resin is preferably 5 parts by mass or more, more preferably 7 parts by mass or more, from the viewpoint of improving the disintegration property of the mold after casting and improving the mold strength. It is more preferably 12 parts by mass or more, still more preferably 15 parts by mass or more, and from the same viewpoint, preferably 50 parts by mass or less, more preferably 35 parts by mass or less, still more preferably 30 parts by mass or less, still more preferably. Is 25 parts by mass or less. The content of the inorganic particles with respect to 100 parts by mass of the phenol resin is preferably 5 to 50 parts by mass, more preferably 7 to 35 parts by mass, from the viewpoint of improving the disintegration property of the mold after casting and improving the mold strength. Parts, more preferably 12 to 30 parts by mass, even more preferably 15 to 25 parts by mass.

With respect to the embodiments described above, the present invention further discloses the following embodiments.
<1> A binder composition for molding, which contains a phenol resin and a cyclic ketal compound having a hydroxyl group and having 5 or more carbon atoms.
<2> The binder composition for molding according to <1>, wherein the cyclic ketal has 20 or less carbon atoms.
<3> The binder composition for molding according to <1> or <2>, wherein the cyclic ketal compound contains a compound represented by the following general formula (1).
(In the above general formula (1), R1 and R2 each represent hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, and R3 and R4 represent hydrogen or -CH ₂ OH groups, respectively. However, R3 and R4 simultaneously represent hydrogen or a -CH 2 OH group. Not hydrogen.)
<4> The binder composition for molding according to <1> or <2>, wherein the cyclic ketal compound contains a compound represented by the following general formula (2).
(In the above general formula (2), R1 and R2 represent hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, respectively. However, R1 and R2 are not hydrogen at the same time.)
<5> In the general formulas (1) and (2), R1 and R2 are R1 being a methyl group and R2 being a methyl group, R1 being a methyl group and R2 being an ethyl group, R1 being a methyl group and R2 being a hydrogen, and R1. The binder composition for molding according to <3> or <4>, wherein is one or more selected from the group consisting of an ethyl group and R2 is an ethyl group.
<6> In any one of <3> to <5>, the content of the compound represented by the general formula (1) or the general formula (2) in the cyclic ketal is 80% by mass or more. The binder composition for molding described.
<7> The invention according to any one of <1> to <6>, wherein the content of the cyclic ketal compound is 0.2% by mass or more and 20% by mass or less in the binder composition for molding. Binder composition for molding.
<8> The template according to any one of <1> to <7>, wherein the content of the cyclic ketal compound is 0.5 parts by mass or more and 40 parts by mass or less with respect to 100 parts by mass of the phenol resin. Molding binder composition.
<9> A phenol resin, a cyclic ketal compound having a hydroxyl group and having 5 or more carbon atoms, and an alcohol are contained, and the alcohol is selected from polyhydric alcohols, glycol ethers, alicyclic glycol compounds, and aromatic alcohols. A binder composition for molding, which comprises seeds or more. <10> The binder composition for molding according to <9>, wherein the cyclic ketal has 20 or less carbon atoms.
<11> The binder composition for molding according to <9> or <10>, wherein the cyclic ketal compound contains a compound represented by the following general formula (1).
(In the above general formula (1), R1 and R2 each represent hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, and R3 and R4 represent hydrogen or -CH ₂ OH groups, respectively. However, R3 and R4 simultaneously represent hydrogen or a -CH 2 OH group. Not hydrogen.)
<12> The binder composition for molding according to <9> or <10>, wherein the cyclic ketal compound contains a compound represented by the following general formula (2).
(In the above general formula (2), R1 and R2 represent hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, respectively. However, R1 and R2 are not hydrogen at the same time.)
<13> In the general formulas (1) and (2), R1 and R2 are R1 being a methyl group and R2 being a methyl group, R1 being a methyl group and R2 being an ethyl group, R1 being a methyl group and R2 being a hydrogen, and R1. The binder composition for molding according to <11> or <12>, wherein is one or more selected from the group consisting of an ethyl group and R2 is an ethyl group.
<14> In any one of <11> to <13>, the content of the compound represented by the general formula (1) or the general formula (2) in the cyclic ketal is 80% by mass or more. The binder composition for molding described.
<15> Of <9> to <14>, the content of one or more selected from the polyhydric alcohol, glycol ether, alicyclic glycol compound and aromatic compound alcohol in the alcohol is 80% by mass or more. The binder composition for molding according to any one of them. <16> The invention according to any one of <9> to <15>, wherein the content of the cyclic ketal compound is 0.2% by mass or more and 10% by mass or less in the binder composition for molding. Binder composition for molding.
<17> The mold molding according to any one of <9> to <16>, wherein the content of the alcohol is 0.5% by mass or more and 15% by mass or less in the binder composition for mold molding. Cinder composition for use.
<18> The template according to any one of <9> to <17>, wherein the content of the cyclic ketal compound is 0.5 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the phenol resin. Molding binder composition.
<19> The caking for molding according to any one of <9> to <18>, wherein the alcohol content is 2 parts by mass or more and 35 parts by mass or less with respect to 100 parts by mass of the phenol resin. Agent composition.
<20> One of <9> to <19>, wherein the total content of the cyclic ketal compound and the alcohol is 1% by mass or more and 20% by mass or less in the binder composition for molding. The above-mentioned binder composition for molding.
<21> The method according to any one of <9> to <20>, wherein the total content of the cyclic ketal compound and the alcohol is 4 parts by mass or more and 40 parts by mass or less with respect to 100 parts by mass of the phenol resin. Cinder composition for molding.
<22> One of <9> to <21>, wherein the ratio of the content of the cyclic ketal compound to the total content of the alcohol and the cyclic ketal compound is 0.1 or more and 0.8 or less. The binder composition for molding described.
<23> A mixing step of mixing the fire-resistant particles and the binder composition for molding according to any one of <1> to <22> to obtain a composition for molding, and for the molding. A method for producing a mold, which comprises a curing step in which the composition is packed in a mold and the composition for molding is cured.
<24> The method for producing a mold according to <23>, wherein the curing agent that cures the molding composition in the curing step is an organic ester compound or carbon dioxide gas.
<25> The casting composition containing the binder composition for molding and the refractory particles according to any one of <1> to <22>.
<26> The composition for molding according to <25>, wherein the content of the binder composition is 10 parts by mass or more and 100 parts by mass or less with respect to 1000 parts by mass of the refractory particles.
<27> A composition for molding, which contains a phenol resin, a cyclic ketal compound having a hydroxyl group and having 5 or more carbon atoms, and refractory particles.
<28> The composition for molding according to <27>, wherein the cyclic ketal has 20 or less carbon atoms.
<29> The composition for molding according to <27> or <28>, wherein the cyclic ketal compound contains a compound represented by the following general formula (1).
(In the above general formula (1), R1 and R2 each represent hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, and R3 and R4 represent hydrogen or -CH ₂ OH groups, respectively. However, R3 and R4 simultaneously represent hydrogen or a -CH 2 OH group. Not hydrogen.)
<30> The composition for molding according to <27> or <28>, wherein the cyclic ketal compound contains a compound represented by the following general formula (2).
(In the above general formula (2), R1 and R2 represent hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, respectively. However, R1 and R2 are not hydrogen at the same time.)
<31> In the general formulas (1) and (2), R1 and R2 are R1 being a methyl group and R2 being a methyl group, R1 being a methyl group and R2 being an ethyl group, R1 being a methyl group and R2 being a hydrogen, and R1. The composition for molding according to <29> or <30>, wherein is one or more selected from the group consisting of an ethyl group and R2 is an ethyl group.
<32> In any one of <29> to <31>, the content of the compound represented by the general formula (1) or the general formula (2) in the cyclic ketal is 80% by mass or more. The above-mentioned composition for molding.
<33> The composition for molding according to <25> to <32>, wherein the content of the phenol resin is 5 parts by mass or more and 80 parts by mass or less with respect to 1000 parts by mass of the refractory particles.
<34> The template according to any one of <25> to <33>, wherein the content of the cyclic ketal compound is 0.5 parts by mass or more and 40 parts by mass or less with respect to 100 parts by mass of the phenol resin. Molding composition.
<35> The composition for molding according to any one of <25> to <34>, which further contains inorganic particles having an average particle diameter of 0.1 to 50 μm.
<36> The composition for molding according to <35>, wherein the content of the inorganic particles is 5 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the phenol resin.
<37> An additive for molding, which contains a cyclic ketal compound having a hydroxyl group and having 5 or more carbon atoms.
<38> The additive for molding according to <37>, wherein the cyclic ketal has 20 or less carbon atoms.
<39> The additive for molding according to <37> or <38>, wherein the cyclic ketal compound contains a compound represented by the following general formula (1).
(In the above general formula (1), R1 and R2 each represent hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, and R3 and R4 represent hydrogen or -CH ₂ OH groups, respectively. However, R3 and R4 simultaneously represent hydrogen or a -CH 2 OH group. Not hydrogen.)
<40> The additive for molding according to <37> or <38>, wherein the cyclic ketal compound contains a compound represented by the following general formula (2).
(In the above general formula (2), R1 and R2 represent hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, respectively. However, R1 and R2 are not hydrogen at the same time.)
<41> In the general formulas (1) and (2), R1 and R2 are R1 being a methyl group and R2 being a methyl group, R1 being a methyl group and R2 being an ethyl group, R1 being a methyl group and R2 being a hydrogen, and R1. The mold molding additive according to <39> or <40>, wherein is one or more selected from the group consisting of an ethyl group and R2 is an ethyl group.
<42> In any one of <39> to <41>, the content of the compound represented by the general formula (1) or the general formula (2) in the cyclic ketal is 80% by mass or more. The above-mentioned additive for molding.

Hereinafter, examples and the like that specifically demonstrate the present invention will be described.

<Raw material evaluation method>
[Weight average molecular weight (Mw) of water-soluble phenol resin]
The weight average molecular weight (Mw) of the water-soluble phenol resin was measured by GPC (gel permeation chromatography) under the following conditions.
(A) Sample preparation: The same weight of ion-exchanged water was added to the sample, and 0.1% by mass of H2SO4 was added for neutralization. The resulting precipitate was filtered off, washed with water and dried. This was dissolved in tetrahydrofuran (THF) to prepare a sample for GPC.
(B) Column: One guard column TSX (manufactured by Toyo Soda Kogyo Co., Ltd.) HXL (6.5 mmφ x 4 cm), one TSK3000HXL (7.8 mmφ x 30 cm), and one TSK2500HXL (7.8 mmφ x 30 cm). use. The guard column-3000HXL-2500HXL was connected in this order from the inlet side.
(C) Standard substance: Monodisperse polystyrene with known weight average molecular weight (manufactured by Toyo Soda Kogyo Co., Ltd.)
(D) Eluate: THF (flow velocity: 1 cm ³ / min)
(E) Column temperature: 25 ° C.
(F) Detector: Ultraviolet spectrophotometer (quantified at the wavelength of the maximum peak of ultraviolet absorption of phenol)
(G) Division method for molecular weight calculation: Time division (2 sec)

[Average particle size]
(For particles of 53 μm or more)
Measured using a sieve of 850, 600, 425, 300, 212, 150, 106, 75, 53 μm based on the method specified in Annex 2 of JIS Z2601 (1993) “Test method for foundry sand”, and mass accumulation. The particle size of 50% is defined as the average particle size.
(For particles smaller than 53 μm)
It is an average particle diameter with a cumulative volume of 50% measured using a laser diffraction type particle size distribution measuring device (LA-920 manufactured by HORIBA, Ltd.). The analysis conditions are as follows.
・ Measurement method: Flow method ・ Dispersion medium: Ion-exchanged water ・ Dispersion method: Stirring, built-in ultrasonic wave 3 minutes ・ Sample concentration: 2 mg / 100 cc

<Preparation of aqueous phenol resin solution>
380 g of phenol, 670 g of 48 mass% potassium hydroxide aqueous solution, 165 g of water and 265 g of 92% paraformaldehyde were mixed in a 2 liter glass container equipped with a thermometer and a stirrer, and then reacted at 85 ° C. to obtain a phenol resin aqueous solution. .. The solid content concentration of the phenol resin aqueous solution is 63.9% by mass. The weight average molecular weight (Mw) of the water-soluble phenol resin is 1820.

<Examples 1 to 16, Comparative Examples 1 to 14>
[Preparation of binder composition]
74 parts by mass of the phenol resin aqueous solution (47.3 parts by mass of phenol resin), 3 parts by mass of sodium aluminate, 6 parts by mass of sodium tetraborate tetrahydrate (borax), 3-glycidoxypropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd.) KBM-403) manufactured by Kogyo Co., Ltd. and 1 part by mass of each of the compounds shown in Table 1 were mixed in a predetermined amount, and then water was mixed so as to have 100 parts by mass to obtain a binder composition.

[Refractory particles]
As the refractory particles, silica sand (“Mikawa silica sand R product No. 6” manufactured by Mikawa silica stone Co., Ltd.) was used. The average particle size was 181 μm.

[Preparation of sample for evaluation of residual template compression strength]
A kitchen mixer equipped with an aluminum beater stirring blade ("Kenmix Aiko Chef" manufactured by Aikosha Seisakusho Co., Ltd.) is charged with 30 parts by mass of the binder composition with respect to 1000 parts by mass of refractory particles and rotated. After mixing at a speed of 300 rpm for 2 minutes, the mixture was filled into a 50 mm × 50 mmφ test piece wooden mold. Then, at 25 ° C., carbon dioxide gas was aerated at a flow rate of 2.5 L / min for 30 seconds to obtain a test piece for evaluation. The test piece was allowed to stand at 25 ° C. for 24 hours, wrapped with aluminum foil (manufactured by UACJ Corporation, "My Foil") so as to cover the entire surface, and then heated in an electric furnace heated to 200 ° C. for 1 hour. Then, it was allowed to stand for 1 hour in an environment of 25 ° C. After that, the aluminum foil was removed to obtain a sample for evaluating the residual mold compressive strength.

[Evaluation method of residual mold compression strength]
A sample for evaluating the residual mold compressive strength was evaluated at a speed of 5 mm / sec using a compressive strength evaluation tester (“SDW 2000SH special type” manufactured by Imada Seisakusho Co., Ltd.), and the residual mold compressive strength was calculated from the load at break. .. The mold compression strength of the test piece after being allowed to stand at 25 ° C. for 24 hours was also measured. The results are shown in Tables 1 and 2. The smaller the difference between the residual mold compressive strength (A) and the mold compressive strength (B), the more the improvement of the residual mold compressive strength is suppressed and the better the mold disintegration property is shown.

From Table 1, the binder compositions of Examples 1 to 5 are different from the binder compositions of Comparative Examples 2 and 4 to 14 in the residual mold compression strength (A) and the mold compression strength (B). It can be seen that the size is small, the improvement of the residual mold compression strength is suppressed, and the mold disintegration property is excellent. Further, in the binder compositions of Comparative Example 1 and Comparative Example 3, the difference between the residual mold compression strength (A) and the mold compression strength (B) is small, but the mold compression strength after standing at 25 ° C. for 24 hours is high. It is low and unusable for practical use.

From Table 2, the binder compositions of Examples 6 to 16 containing alcohol have improved mold compression strength, and the difference between the residual mold compression strength (A) and the mold compression strength (B) is also small.

<Examples 17 to 21>
In a kitchen mixer equipped with an aluminum beater stirring blade (“Kenmix Aiko Chef” manufactured by Aikosha Seisakusho Co., Ltd.), 30 parts by mass of the binder composition of Example 10 was added to 1000 parts by mass of fire-resistant particles. 3 parts by mass of the inorganic particles shown in 4 were charged, mixed at a rotation speed of 300 rpm for 2 minutes, and then filled in a wooden mold for a test piece having a size of 50 mm × 50 mmφ. Then, at 25 ° C., carbon dioxide gas was aerated at a flow rate of 2.5 L / min for 30 seconds to obtain a test piece for evaluation. Using the obtained evaluation test piece, the same evaluation as in Example 10 was performed. The results are shown in Table 3. Table 4 shows the properties of the inorganic particles used.

From the above results, by incorporating the inorganic particles into the mold composition, the difference between the residual mold compression strength (A) and the mold compression strength (B) is further small, the improvement of the residual mold compression strength is suppressed, and the mold collapses. It turns out that it is excellent in sex.

Claims (12)

A binder composition for molding, which contains a phenol resin and a cyclic ketal compound having a hydroxyl group and having 5 or more carbon atoms. The binder composition for molding according to claim 1, wherein the content of the cyclic ketal compound is 0.2% by mass or more and 30% by mass or less in the binder composition for molding. The binder composition for molding according to claim 1 or 2, wherein the content of the cyclic ketal compound is 0.5 parts by mass or more and 65 parts by mass or less with respect to 100 parts by mass of the phenol resin. The binder composition for molding according to any one of claims 1 to 3, wherein the cyclic ketal compound having a hydroxyl group has 20 or less carbon atoms. The binder composition for molding according to any one of claims 1 to 4, wherein the cyclic ketal compound is a compound represented by the following general formula (1).
(In the above general formula (1), R1 and R2 each represent hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, and R3 and R4 represent hydrogen or -CH ₂ OH groups, respectively. However, R3 and R4 simultaneously represent hydrogen or a -CH 2 OH group. Not hydrogen.) A mixing step of mixing the fire-resistant particles and the binder composition for molding according to any one of claims 1 to 5 to obtain a composition for molding, and a mold for the composition for molding. A method for producing a mold, which comprises a curing step of filling in a mold and curing the molding composition. The method for producing a mold according to claim 6, wherein the curing agent for curing the molding composition in the curing step is an organic ester compound or carbon dioxide gas. A mold molding composition containing the mold molding binder composition according to any one of claims 1 to 5 and refractory particles. A composition for molding containing a phenol resin, a cyclic ketal compound having 5 or more carbon atoms having a hydroxyl group, and refractory particles. The composition for molding according to claim 8 or 9, further containing inorganic particles having an average particle diameter of 0.1 to 50 μm. The composition for molding according to claim 10, wherein the content of the inorganic particles is 5 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the phenol resin. An additive for molding containing a cyclic ketal compound having a hydroxyl group and having 5 or more carbon atoms.