CN113891771B

CN113891771B - Adhesive composition for casting mold

Info

Publication number: CN113891771B
Application number: CN202080038660.2A
Authority: CN
Inventors: 神泽智史; 石山翔午; 山谷满喜人; 中畑优
Original assignee: Kao Corp
Current assignee: Kao Corp
Priority date: 2019-09-09
Filing date: 2020-07-09
Publication date: 2024-05-10
Anticipated expiration: 2040-07-09
Also published as: WO2021049150A1; JP6798059B1; CN113891771A; JP2021041459A

Abstract

The present invention relates to a binder composition for mold molding, which 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, there can be provided a binder composition for molding a mold, which can improve the disintegration property of the mold (i.e., reduce the compressive strength of the residual mold) and improve the productivity of the demolding operation after casting.

Description

Adhesive composition for casting mold

Technical Field

The present invention relates to a binder composition for mold molding.

Background

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

While a mold is required to have a strength that can withstand handling and casting of molten metal, a high degree of disintegration is required to facilitate removal of a cast after casting and to shorten the time required for a mold stripping operation.

The organic binder is considered to have good disintegrating property because the binder is thermally decomposed by heat at the time of casting, but the phenolic resin is heated at about 100 to 300 ℃ to be cured for so-called 2 times, so that the mold strength is increased, and thus the disintegrating property of the part heated in this range at the time of casting is lowered.

In order to solve the above problems, JP-A-7-148546, JP-A-10-193033 and JP-A-9-57391 propose methods of adding a metal salt compound and the like.

Disclosure of Invention

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

The method for producing a mold of the present invention comprises: a mixing step of mixing refractory particles with the binder composition for mold molding to obtain a composition for mold molding; and a curing step of filling the composition for mold molding into a mold and curing the composition for mold molding.

The composition for molding of the present invention contains the binder composition for molding and refractory particles.

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

Detailed Description

The conventional binder composition for molding is insufficient in terms of the disintegrating property of the mold, and there is room for improvement.

The present invention provides a binder composition for mold molding, a composition for mold molding, an additive for mold molding, and a method for producing a mold, which can improve the productivity of a demolding operation after casting by improving the disintegrability of a mold (i.e., reducing the residual strength) without reducing the mold strength at the time of mold molding.

According to the present invention, there can be provided a binder composition for mold molding, a composition for mold molding, an additive for mold molding, and a method for producing a mold, which can improve the disintegration of a mold and improve the productivity of a demolding operation after casting without deteriorating the mold strength at the time of mold molding.

An embodiment of the present invention will be described below.

Adhesive composition for mold shaping

The binder composition for mold molding of the present embodiment (hereinafter, also referred to as binder composition) is a binder composition for mold molding, which contains a phenolic resin and a cyclic ketal compound having a hydroxyl group and having 5 or more carbon atoms (hereinafter, also referred to as cyclic ketal compound). According to the adhesive composition of the present embodiment, the residual mold compression strength of the cast mold can be suppressed from being increased without decreasing the mold strength at the time of molding the mold, and thus the disintegration of the mold can be increased, and the productivity of the demolding operation of the cast mold can be improved. Since the disintegration of the mold is improved, the amount of aggregates which are generated during the breaking treatment of the casting sand and cannot be broken into individual sand particles is reduced, and the amount of waste is reduced. In addition, the residual resin at the time of reclamation of the foundry sand is easily removed, so that the LOI (loss on ignition) of the reclaimed sand is reduced, and the mold strength using the reclaimed sand is improved. In addition, it is considered that since there is almost no 2 times of solidification due to heating, in the field of cast steel having a large solidification shrinkage, a mold can follow the solidification shrinkage of a cast piece after casting, and thus cracking defects at the time of shrinkage of the cast piece are also reduced. The reason for exhibiting such effects is not yet determined, but is considered as described below.

When the phenolic resin is contained in the composition for a mold, the phenolic resin is usually cured 2 times 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 disintegrate. However, it is considered that 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 moderately compatible with the phenolic resin because of its moderate hydrophobicity, and moderately coordinates to a phenolic hydroxyl group or the like that is a reaction site of the phenolic resin, and thus, it is possible to suppress the increase in the compressive strength of the residual mold and to improve the disintegrability of the mold by suppressing the 2-time curing of the phenolic resin.

[ Phenolic resin ]

The above phenolic resin is generally a product obtained by polycondensing a phenol compound with an aldehyde compound under alkaline conditions. Among them, as the phenol compound, a mixture of 1 or more kinds of phenol compounds or a mixture of 2 or more kinds of phenol compounds including phenol, bisphenol a, bisphenol F, cresol, 3, 5-xylenol, resorcinol, catechol, nonylphenol, p-tert-butylphenol, isopropenylphenol, phenylphenol, other substituted phenols, cashew nut shell liquid, and the like can be used. As the aldehyde compound, 1 or a mixture of 2 or more types of formaldehyde, acetaldehyde, furfural, glyoxal, and the like can be used. These compounds may be used in the form of an aqueous solution, as required. In addition, these may be mixed with a monomer capable of condensing with an aldehyde compound, such as urea, melamine, and cyclohexanone; 1-membered aliphatic alcohol compounds such as methanol, ethanol, isopropanol, n-propanol, butanol, etc.; polyacrylate of water-soluble polymer; cellulose derivative polymers, polyvinyl alcohol, lignin derivatives, and the like.

The alkali catalyst used for the synthesis of the phenolic resin includes hydroxides of alkali metals such as LiOH, naOH, KOH, and NaOH and KOH are particularly preferable. In addition, these base catalysts may be used in combination.

The phenolic resin is preferably prepared as an aqueous solution, and is preferably 30 mass% or more, more preferably 50 mass% or more, as the mass of the solid component (the mass of the solid after drying at 105 ℃ for 3 hours) from the viewpoint of improving the mold strength. From the viewpoint of improving the mold strength and workability, the mass of the solid content of the aqueous phenolic resin solution is preferably 85 mass% or less, more preferably 75 mass% or less. The mass of the solid content of the aqueous phenolic resin solution is preferably 30 to 80% by mass, more preferably 50 to 75% by mass, from the viewpoint of improving the mold strength and improving the workability.

The weight average molecular weight (Mw) of the phenolic resin is preferably 500 or more, more preferably 800 or more, and even more preferably 1200 or more, from the viewpoint of improving the mold strength. From the viewpoint of improving the mold strength and workability, the weight average molecular weight (Mw) of the phenolic resin is preferably 8000 or less, more preferably 5000 or less, and further preferably 3000 or less. The weight average molecular weight (Mw) of the phenolic 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 workability. The weight average molecular weight of the phenolic resin was measured by the method described in examples.

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

[ Cyclic ketal Compound having hydroxyl group and having 5 or more carbon atoms ]

The cyclic ketal compound has a carbon number of 5 or more, preferably 6 or more, from the viewpoint of improving the disintegrability of the cast mold after casting. From the same viewpoint, the cyclic ketal compound preferably has a carbon number of 20 or less, more preferably 14 or less, still more preferably 10 or less, and still more preferably 8 or less.

The molecular weight of the cyclic ketal compound is preferably 110 or more, more preferably 115 or more, and even more preferably 130 or more, from the viewpoint of improving the disintegrability of the cast 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, further preferably 150 or less, and further preferably 140 or less.

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

The number of hydroxyl groups in 1 molecule of the cyclic ketal compound is preferably 4 or less, more preferably 3 or less, further preferably 2 or less, and still further preferably 1, from the viewpoint of improving the disintegrability of the mold after casting.

In addition, from the viewpoint of improving the disintegrability of the mold after casting, the cyclic ketal compound is preferably a compound having 1 cyclic ketal structure and having 2 hydroxyl groups, and a compound having 1 cyclic ketal structure and having 1 hydroxyl group, and more preferably a compound having 1 cyclic ketal structure and having 1 hydroxyl group.

The cyclic ketal compound can be obtained by reacting a 3-or more-membered polyol with 1 or more selected from aldehydes and ketones.

The number of the polyol is preferably 3 or more, preferably 8 or less, more preferably 6 or less, and even more preferably 4 or less, from the viewpoint of improving the disintegrability and the acquirability of the cast mold.

The 3-or more-membered polyol includes: glycerol, trimethylolethane, trimethylolpropane, erythritol, pentaerythritol, xylitol, sorbitol, mannitol, dipentaerythritol, and the like.

The carbon number of the aldehyde and ketone is preferably 1 or more, more preferably 2 or more from the viewpoint of improving the disintegrability and the acquirability of the cast mold after casting, and is preferably 25 or less, more preferably 10 or less, more preferably 5 or less, more preferably 4 or less, more preferably 3 or less from the same viewpoint.

The aldehydes and ketones include: formaldehyde, acetaldehyde, acetone, propionaldehyde, methyl ethyl ketone, butyraldehyde, valeraldehyde, 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 disintegrability of a cast mold after casting.

[ Chemical formula 1]

( In the general formula (1), R1 and R2 each represent hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, and R3 and R4 each represent hydrogen or a-CH ₂ OH group. But R3 and R4 are not both hydrogen. )

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

[ Chemical formula 2]

( In the general formula (2), R1 and R2 each represent hydrogen or a hydrocarbon group having 1 to 10 carbon atoms. But R1 and R2 are not both hydrogen. )

The hydrocarbyl group denoted by R1 and R2 in the formulae (1) and (2) is preferably an alkyl group, from the viewpoint of improving the disintegrating property and the availability of the cast mold.

From the viewpoint of improving the disintegration property and the availability of the cast mold after casting, the carbon numbers of R1 and R2 in the above general formulae (1) and (2) are preferably 1 to 4, more preferably 1 to 3, still more preferably 1 to 2, and still more preferably 2.

The hydrocarbon groups of R1 and R2 in the above general formulae (1) and (2) are preferably methyl, ethyl, n-propyl, isopropyl, n-butyl, more preferably methyl and ethyl, and still more preferably methyl, from the viewpoint of improving the disintegrability and the acquirability of the cast mold.

From the viewpoint of improving the disintegration property and the availability of the cast mold after casting, at least one of R1 and R2 in the above general formulae (1) and (2) is preferably an alkyl group, more preferably both are alkyl groups.

Regarding R1 and R2 in the above general formulae (1) and (2), from the viewpoint of improving the disintegrability and the acquirability of the cast mold after casting, it is preferable that R1 is methyl and R2 is methyl, R1 is methyl and R2 is ethyl, R1 is methyl and R2 is hydrogen, R1 is ethyl and R2 is ethyl, more preferably R1 is methyl and R2 is methyl, R1 is methyl and R2 is ethyl, R1 is methyl and R2 is hydrogen, still more preferably R1 is methyl and R2 is methyl.

In the above general formula (2), R3 and R4 are preferably selected from the group consisting of R1 is hydrogen and R2 is-CH ₂ OH group, from the viewpoint of improving the disintegrability and the availability of the cast mold after casting. That is, the compound represented by the above general formula (1) is preferably a compound represented by the above 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, more preferably 90% by mass or more, still more preferably 95% by mass or more, still more preferably 100% by mass, from the viewpoint of improving the disintegrability and the availability of the cast mold after casting.

The content of the cyclic ketal compound in the binder composition is preferably 0.2 mass% or more, more preferably 0.5 mass% or more, still more preferably 1 mass% or more, still more preferably 2 mass% or more, still more preferably 4 mass% or more, still more preferably 8 mass% or more, and from the same viewpoint, preferably 30 mass% or less, more preferably 25 mass% or less, and still more preferably 20 mass% or less. The content of the cyclic ketal compound in the binder composition is preferably 0.2 to 30% by mass, more preferably 0.5 to 30% by mass, still 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, and still more preferably 8 to 20% by mass, from the viewpoint of improving the disintegrability of a cast mold after casting and from the viewpoint of improving the mold strength.

The content of the cyclic ketal compound is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, still 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 less, more preferably 50 parts by mass or less, still more preferably 40 parts by mass or less, relative to 100 parts by mass of the phenolic resin, from the viewpoint of improving the disintegrability of the cast mold after casting and from the viewpoint of improving the mold strength. The content of the cyclic ketal compound is preferably 0.5 to 65 parts by mass, more preferably 0.5 to 50 parts by mass, still 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 preferably 8 to 40 parts by mass, and still more preferably 16 to 40 parts by mass, relative to 100 parts by mass of the phenolic resin, from the viewpoint of improving the disintegrability of a cast mold after casting and from the viewpoint of improving the mold strength.

[ Other Components ]

The adhesive composition may further contain additives such as water, alcohols, silane coupling agents, oxyanion compounds, surfactants, and the like to such an extent that the effects of the present embodiment are not impaired.

[ Alcohol ]

The binder composition preferably contains an alcohol from the viewpoint of improving the mold strength. The alcohol is preferably 1 or more selected from the group consisting of polyhydric alcohols, glycol ethers, alicyclic glycol compounds and aromatic alcohols. Examples of the alcohol include: polyhydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 2-dimethyl-1, 3-propanediol, and glycerin; glycol ethers such as 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, dipropylene glycol monomethyl ether, and the like; alicyclic diol compounds such as cyclohexanediol and cyclohexanedimethanol; phenoxy alcohols such as 2-phenoxyethanol, 2-phenoxypropanol, and 1-phenoxy-2-propanol, and aromatic alcohols such as benzyl alcohol. When carbon dioxide is used as the curing agent, 1 or more selected from the group consisting of glycol ethers and aromatic alcohols is preferable, and 1 or more selected from the group consisting of triethylene glycol monoethyl ether, diethylene glycol monoethyl ether and 2-phenoxyethanol is more preferable from the viewpoint of improving the mold strength.

From the viewpoint of improving the disintegrability of the cast mold after casting, the content of 1 or more selected from the group consisting of polyhydric alcohols, glycol ethers, alicyclic glycol compounds and aromatic compound alcohols is preferably 80 mass% or more, more preferably 90 mass% or more, still more preferably 95 mass% or more, and still more preferably 100 mass% or more.

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

The content of the alcohol 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 parts by mass or more, based on 100 parts by mass of the phenolic resin, from the viewpoint of improving the mold strength after casting, and from the viewpoint of improving the mold disintegrability after casting, preferably 40 parts by mass or less, more preferably 35 parts by mass or less, still more preferably 20 parts by mass or less, still more preferably 18 parts by mass or less, and still more preferably 13 parts by mass or less. From the viewpoint of improving the disintegrability of the cast mold after casting and the viewpoint of improving the mold strength, the content of the alcohol is preferably 1 to 40 parts by mass, more preferably 2 to 35 parts by mass, still more preferably 4 to 20 parts by mass, still more preferably 4 to 18 parts by mass, still more preferably 4 to 13 parts by mass, and still more preferably 8 to 13 parts by mass, relative to 100 parts by mass of the phenolic resin.

The content of the cyclic ketal compound in the binder composition containing the alcohol is preferably 0.2 mass% or more, more preferably 0.5 mass% or more, still more preferably 1 mass% or more, still more preferably 2 mass% or more, still more preferably 4 mass% or more, from the viewpoint of improving the disintegrability of the cast mold after casting and from the viewpoint of improving the mold strength, and from the same viewpoint, preferably 18 mass% or less, more preferably 15 mass% or less, still more preferably 10 mass% or less, still more preferably 7 mass% or less. The content of the cyclic ketal compound in the adhesive composition is preferably 0.2 to 18% by mass, more preferably 0.2 to 15% by mass, still 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 still more preferably 4 to 7% by mass, from the viewpoint of improving the disintegrability of a cast mold after casting and from the viewpoint of improving the mold strength.

In the binder composition containing the alcohol, the content of the cyclic ketal compound is preferably 0.5 parts 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 parts by mass or more, from the viewpoint of improving the disintegrability of the cast mold after casting and from the viewpoint of improving the mold strength, and from the same viewpoint, preferably 30 parts by mass or less, more preferably 25 parts by mass or less, still more preferably 18 parts by mass or less, and still more preferably 14 parts by mass or less, relative to 100 parts by mass of the phenolic resin. In the binder composition containing the alcohol, the content of the cyclic ketal compound is preferably 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, still more preferably 8 to 18 parts by mass, and still more preferably 8 to 14 parts by mass, relative to 100 parts by mass of the phenolic resin, from the viewpoint of improving the disintegrability of a cast after casting and improving the strength of the cast.

The total content of the cyclic ketal compound and the alcohol in the binder composition is preferably 1% by mass or more, more preferably 2% by mass or more, still more preferably 4% by mass or more, still more preferably 8% by mass or more, from the viewpoint of improving the disintegrability of the cast after casting and from the viewpoint of improving the mold strength, preferably 20% by mass or less, more preferably 15% by mass or less, and 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, more preferably 2 to 20% by mass, further preferably 4 to 20% by mass, still more preferably 4 to 15% by mass, and still more preferably 8 to 12% by mass, from the viewpoint of improving the disintegrability of the cast mold after casting and from the viewpoint of improving the mold strength.

The total content of the cyclic ketal compound and the alcohol is preferably 2 parts by mass or more, 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, relative to 100 parts by mass of the phenolic resin, from the viewpoint of improving the disintegrability of the cast mold after casting and from the viewpoint of improving the mold strength, and is preferably 40 parts by mass or less, more preferably 35 parts by mass or less, and still more preferably 25 parts by mass or less. From the viewpoint of improving the disintegrability of the cast mold after casting and from the viewpoint of improving the mold strength, the total content of the cyclic ketal compound and the alcohol is preferably 2 to 40 parts by mass, more preferably 4 to 40 parts by mass, still more preferably 4 to 35 parts by mass, still more preferably 8 to 35 parts by mass, and still more preferably 16 to 25 parts by mass, relative to 100 parts by mass of the phenolic resin.

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, still more preferably 0.3 or more, still more preferably 0.4 or more, from the viewpoint of improving the disintegrability of the cast, preferably 0.8 or less, more preferably 0.7 or less, still more preferably 0.6 or less, from the viewpoint of improving the cast strength. 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 to 0.8, more preferably 0.2 to 0.8, still more preferably 0.4 to 0.6, from the viewpoint of improving the disintegrability of the cast after casting, preferably 0.4 to 0.8, and from the viewpoint of improving the strength of the cast, preferably 0.2 to 0.7, more preferably 0.2 to 0.6, from the viewpoint of improving the disintegrability of the cast after casting.

[ Silane coupling agent ]

From the viewpoint of improving the mold strength, the adhesive composition preferably contains a silane coupling agent. The silane coupling agent may be: gamma- (2-amino) propylmethyldimethoxy silane, gamma-aminopropyl trimethoxy silane, gamma-aminopropyl triethoxy silane, gamma-glycidoxypropyl trimethoxy silane, N-beta- (aminoethyl) gamma-aminopropyl methyldimethoxy silane, etc. The content of the silane coupling agent in the adhesive composition is preferably 0.1 to 5% by mass, more preferably 0.3 to 1% by mass, from the viewpoint of improving the mold strength.

[ Oxyanion Compound ]

In the case of curing the binder composition with carbon dioxide, it is preferable to contain an oxyanion compound from the viewpoint of improving the strength of the mold and from the viewpoint of improving the curing speed of the mold. This is because it is considered that the oxyanion compound forms an ionomer after absorbing carbon dioxide, and thus the water-soluble phenol resin is polymerized. Examples of the oxyanion compound include: boric acid, borates, aluminates, stannates, and the like. Examples of the borate include: sodium tetraborate 10 hydrate (borax), potassium tetraborate 10 hydrate, sodium metaborate, sodium pentaborate, potassium pentaborate and the like. As the aluminate, sodium aluminate is exemplified. The content of the oxyanion compound in the binder composition is preferably 0.1 to 30% by mass, more preferably 0.5 to 12% by mass, and even more preferably 1 to 8% by mass, from the viewpoint of improving the mold strength and the curing speed of the mold.

Method for producing mold

In the method of manufacturing a mold according to the present embodiment, a mold can be manufactured directly by a conventional mold manufacturing process. A preferred method for producing a mold includes a method for producing a mold having at least the following steps: a mixing step of mixing the refractory particles with the binder composition to obtain a composition for molding; and a curing step of filling the composition for mold molding into a mold and curing the composition for mold molding.

[ Mixing procedure ]

[ Refractory particles ]

As the refractory particles that can be used in the method for producing a mold according to the present embodiment, conventionally known materials such as silica sand, chromite sand, zircon sand, olivine sand, alumina sand, mullite sand, synthetic mullite sand, and alumina ball sand can be used, and reclaimed sand obtained by reclaiming and reclaiming the used refractory particles can be used. The refractory particles may be used alone or in combination of 2 or more.

The average particle diameter of the refractory particles is preferably greater than 50. Mu.m, more preferably 70. Mu.m, still more preferably 120. Mu.m, still more preferably 150. Mu.m, and from the same point of view, it is preferably 600. Mu.m or less, more preferably 400. Mu.m, still more preferably 300. Mu.m, still more preferably 250. Mu.m. In the present specification, the average particle diameter is measured by the method described in examples.

In the above-mentioned mixing step, as a method for mixing the raw materials, a known general method can be used, and examples thereof include: a method of kneading by adding each raw material by a batch mixer, and a method of kneading by supplying each raw material to a continuous mixer.

The ratio of the refractory particles to the binder composition may be appropriately set, and from the viewpoint of improving the mold strength and from the viewpoint of economy, the content of the binder composition is preferably 10 parts by mass or more, and preferably 100 parts by mass or less, relative to 1000 parts by mass of the refractory particles. The phenolic 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 a composition for molding is obtained, the cyclic ketal compound may be further mixed in addition to the binder composition. In this case, the content of the cyclic ketal compound in the molding composition is preferably in a range of 100 parts by mass of the phenolic resin.

Further, a binder composition containing refractory particles and a phenolic resin but containing no cyclic ketal compound may be mixed with the cyclic ketal compound to obtain a composition for molding. The amount of the cyclic ketal compound blended in this case is the same as the content described in the above adhesive composition.

Further, the refractory particles, the phenolic resin, the cyclic ketal compound, and other components used in the binder composition may be mixed to obtain a composition for molding a mold. The content of the phenolic resin in this case is preferably 5 parts by mass or more, and preferably 80 parts by mass or less, relative to 1000 parts by mass of the refractory particles. The amount of the cyclic ketal compound blended with other components used in the adhesive composition is the same as the content described in the adhesive composition.

In the case where the cyclic ketal compound is mixed in addition to the binder composition as described above, the cyclic ketal compound is an additive for mold shaping. The additive for mold formation of the present embodiment contains a cyclic ketal compound having a hydroxyl group and having 5 or more carbon atoms. The additive for molding a mold can reduce the residual strength of a cast mold after casting, improve the disintegration of the mold, and improve the productivity of the mold stripping operation after casting. The preferred mode of the cyclic ketal compound in the additive for mold formation of the present invention is the same as the preferred mode of the cyclic ketal compound in the binder composition for mold formation.

[ Curing Process ]

In the curing step, the composition for mold molding is charged into a mold, and the composition for mold molding is cured. As a method for curing the composition for molding, a known general method can be used. As a method for curing the composition for mold molding, a method of curing with a curing agent is mentioned. The curing agent may be: organic ester compounds, carbon dioxide, and the like.

The organic ester compound may be a lactone having 3 to 10 carbon atoms, an organic ester produced by a polyol having 1 to 10 carbon atoms or a 1-or a polyol and an organic carboxylic acid having 1 to 10 carbon atoms, or an alkylene carbonate having 1 to 8 carbon atoms, singly or in combination. Among the self-curing mold forming methods, gamma-butyrolactone, propiolactone, epsilon-caprolactone, ethyl formate, ethylene glycol diacetate, ethylene glycol monoacetate, triacetin, ethylene carbonate, propylene carbonate and the like are preferably used, and among the gas-curing mold forming methods using an organic ester, methyl formate is preferably used.

In the case of using an organic ester as the curing agent, the amount of the organic ester is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, and further preferably 35 parts by mass or less, more preferably 30 parts by mass or less, based on 100 parts by mass of the adhesive composition, from the viewpoint of improving the mold strength, improving the curing speed, and improving the economy.

In the case of using an organic ester as the curing agent, the amount of the organic ester is preferably 20 parts by mass or more, more preferably 30 parts by mass or more, and further preferably 70 parts by mass or less, more preferably 60 parts by mass or less, based on 100 parts by mass of the phenolic resin, from the viewpoint of improving the mold strength, improving the curing speed, and improving the economy.

In the case of using carbon dioxide as the curing agent, the flow rate of carbon dioxide is preferably 0.2L/min or more, more preferably 1L/min or more per 100cm ³ of the mold from the viewpoint of improving the mold strength, and is preferably 30L/min or less, more preferably 15L/min or less, more preferably 7L/min or less, still more preferably 4L/min or less per 100cm ³ of the mold from the viewpoint of economy. The flow time of carbon dioxide is preferably 10 seconds or more, more preferably 20 seconds or more, further preferably 30 seconds or more from the viewpoint of improving the mold strength, and is preferably 90 seconds or less, more preferably 70 seconds or less, further preferably 50 seconds or less from the viewpoint of economy. The temperature at the time of curing is preferably-5℃or higher, more preferably 5℃or higher, further preferably 10℃or higher, from the viewpoint of improving the mold strength, and from the viewpoint of economy, it is preferably 45℃or lower, more preferably 40℃or lower, further preferably 35℃or lower.

In the case of using carbon dioxide as the curing agent, the amount of carbon dioxide is preferably 25 parts by mass or more, more preferably 30 parts by mass or more, and further preferably 100 parts by mass or less, more preferably 75 parts by mass or less, relative to 100 parts by mass of the binder composition, from the viewpoints of improving the mold strength, improving the curing speed, and improving the economy.

In the case of using carbon dioxide as the curing agent, the amount of carbon dioxide is preferably 50 parts by mass or more, more preferably 60 parts by mass or more, and further preferably 200 parts by mass or less, more preferably 150 parts by mass or less, per 100 parts by mass of the phenolic resin, from the viewpoints of improving the mold strength, improving the curing speed, and improving the economy.

Composition for mold shaping

The composition for molding of the present embodiment contains refractory particles and the binder composition. That is, the composition for mold molding of the present embodiment contains refractory particles, a phenolic resin, and the cyclic ketal compound.

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

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

[ Inorganic particles ]

From the viewpoint of improving the disintegrability of the cast mold after casting, the composition for molding a cast mold of the present embodiment preferably contains inorganic particles. It is considered that the inorganic particles are present in the cured adhesive composition, and that the thermal expansion coefficient of the inorganic particles is different from that of the cured adhesive composition, and thus the decrease in the residual strength after heating is promoted.

The inorganic particles include: silica, mullite, kaolin, fly ash (fly ash). The inorganic particles may be amorphous or crystalline.

The inorganic particles may be spherical, massive, amorphous, or the like, but are preferably spherical particles from the viewpoint of improving the disintegrability of the cast after casting and from the viewpoint of improving the strength of the cast.

The average particle diameter 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 disintegrability of the cast mold after casting, and is preferably 50 μm or less, more preferably 25 μm or less, still more preferably 18 μm or less, from the same viewpoint.

The content of the inorganic particles is preferably 5 parts by mass or more, more preferably 7 parts by mass or more, still more preferably 12 parts by mass or more, still more preferably 15 parts by mass or more, based on 100 parts by mass of the phenolic resin, from the viewpoint of improving the disintegrating property of the cast mold after casting and from the viewpoint of improving the mold strength, 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 25 parts by mass or less. The content of the inorganic particles is preferably 5 to 50 parts by mass, more preferably 7 to 35 parts by mass, still more preferably 12 to 30 parts by mass, and still more preferably 15 to 25 parts by mass, relative to 100 parts by mass of the phenolic resin, from the viewpoint of improving the disintegrability of the cast mold after casting and from the viewpoint of improving the mold strength.

With respect to the above embodiments, the present invention further discloses the following embodiments.

[1] A binder composition for mold molding, which contains a phenolic resin and a cyclic ketal compound having a hydroxyl group and having 5 or more carbon atoms.

The binder composition for casting mold according to <2 > to < 1 >, wherein the cyclic ketal has a carbon number of 20 or less.

< 3 > The binder composition for mold molding according to < 1 > or < 2 >, wherein the cyclic ketal compound comprises a compound represented by the following general formula (1).

[ Chemical formula 3]

< 4 > The binder composition for mold shaping according to < 1 > or < 2 >, wherein the cyclic ketal compound comprises a compound represented by the following general formula (2).

[ Chemical formula 4]

The binder composition for mold molding according to the general formulae (1) and (2) above, wherein R1 and R2 are at least 1 selected from the group consisting of R1 is methyl, R2 is methyl, R1 is methyl, R2 is ethyl, R1 is methyl, R2 is hydrogen, R1 is ethyl, and R2 is ethyl.

The binder composition for molding according to any one of < 3 > - < 5 >, wherein the content of the compound represented by the general formula (1) or the general formula (2) in the cyclic ketal is 80 mass% or more.

The binder composition for mold molding according to any one of < 1 > - < 6 >, wherein the content of the cyclic ketal compound in the binder composition for mold molding is 0.2 mass% or more and 20 mass% or less.

The binder composition for molding according to any one of < 1 > - < 7 >, wherein the content of the cyclic ketal compound is 0.5 parts by mass or more and 40 parts by mass or less based on 100 parts by mass of the phenolic resin.

< 9 > An adhesive composition for mold molding comprising a phenolic resin, a cyclic ketal compound having a hydroxyl group and having 5 or more carbon atoms, and an alcohol comprising 1 or more selected from the group consisting of a polyhydric alcohol, a glycol ether, an alicyclic glycol compound and an aromatic alcohol.

The binder composition for casting mold according to < 10 > to < 9 >, wherein the cyclic ketal has a carbon number of 20 or less.

< 11 > The binder composition for mold shaping according to < 9 > or < 10 >, wherein the cyclic ketal compound comprises a compound represented by the following general formula (1).

[ Chemical formula 5]

< 12 > The binder composition for mold shaping according to < 9 > or < 10 >, wherein the cyclic ketal compound comprises a compound represented by the following general formula (2).

[ Chemical formula 6]

The binder composition for molding according to any one of < 14 > to < 11 > to < 13 >, wherein the content of the compound represented by the general formula (1) or the general formula (2) in the cyclic ketal is 80 mass% or more.

The binder composition for casting mold according to any one of < 9 > - < 14 >, wherein the content of 1 or more selected from the group consisting of polyhydric alcohols, glycol ethers, alicyclic glycol compounds and aromatic compound alcohols in the above-mentioned alcohol is 80% by mass or more.

The binder composition for mold molding according to any one of < 9 > - < 15 >, wherein the content of the cyclic ketal compound in the binder composition for mold molding is 0.2 mass% or more and 10 mass% or less.

The binder composition for mold molding of any one of < 9 > - < 16 >, wherein the content of the alcohol in the binder composition for mold molding is 0.5 mass% or more and 15 mass% or less.

The binder composition for molding of any one of < 9 > - < 17 >, wherein the content of the cyclic ketal compound is 0.5 parts by mass or more and 20 parts by mass or less based on 100 parts by mass of the phenolic resin.

The binder composition for molding of any one of < 9 > - < 18 >, wherein the alcohol content is 2 parts by mass or more and 35 parts by mass or less based on 100 parts by mass of the phenolic resin.

The binder composition for mold molding according to any one of < 9 > - < 19 >, wherein the total content of the cyclic ketal compound and the alcohol is 1 mass% or more and 20 mass% or less in the binder composition for mold molding.

The binder composition for molding of any one of < 21 > to < 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 based on 100 parts by mass of the phenolic resin.

The binder composition for molding of any one of < 22 > to < 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 to 0.8.

< 23 > A method for producing a mold, comprising: a mixing step of mixing refractory particles with the binder composition for mold molding of any one of < 1 > - < 22 > to obtain a composition for mold molding; and a curing step of filling the composition for mold molding into a mold and curing the composition for mold molding.

The method for producing a mold according to < 24 > or < 23 >, wherein the curing agent used for curing the composition for molding a mold in the curing step is an organic ester compound or carbon dioxide.

A composition for molding comprising the binder composition for molding of any one of < 1 > - < 22 > and refractory particles.

The composition for molding of < 26 > to < 25 >, wherein the content of the binder composition is 10 parts by mass or more and 100 parts by mass or less based on 1000 parts by mass of the refractory particles.

< 27 > A composition for molding comprising a phenolic resin, a cyclic ketal compound having a hydroxyl group and having 5 or more carbon atoms, and refractory particles.

The composition for molding of < 28 > according to < 27 >, wherein the cyclic ketal has a carbon number of 20 or less.

The composition for molding of < 29 > according to < 27 > or < 28 >, wherein the cyclic ketal compound comprises a compound represented by the following general formula (1).

[ Chemical formula 7]

The composition for molding of < 30 > according to < 27 > or < 28 >, wherein the cyclic ketal compound comprises a compound represented by the following general formula (2).

[ Chemical formula 8]

The composition for molding of < 31 > according to < 29 > or < 30 > wherein, in the general formulae (1) and (2), R1 and R2 are selected from 1 or more of R1 is methyl, R2 is methyl, R1 is methyl, R2 is ethyl, R1 is methyl, R2 is hydrogen, R1 is ethyl, and R2 is ethyl.

The composition for molding of any one of < 32 > to < 29 > - < 31 >, wherein the content of the compound represented by the general formula (1) or the general formula (2) in the cyclic ketal is 80 mass% or more.

The composition for molding of any one of < 33 > to < 25 > to < 32 >, wherein the content of the phenolic resin is 5 to 80 parts by mass inclusive with respect to 1000 parts by mass of the refractory particles.

The composition for molding of any one of < 25 > - < 33 >, wherein the content of the cyclic ketal compound is 0.5 parts by mass or more and 40 parts by mass or less based on 100 parts by mass of the phenolic resin.

The composition for molding of any one of < 35 > to < 25 > to < 34 >, which further comprises inorganic particles having an average particle diameter of 0.1 to 50. Mu.m.

The composition for molding of < 36 > to < 35 >, wherein the content of the inorganic particles is 5 parts by mass or more and 50 parts by mass or less based on 100 parts by mass of the phenolic resin.

< 37 > An additive for mold molding comprising a cyclic ketal compound having a hydroxyl group and having 5 or more carbon atoms.

The additive for molding of < 38 > and < 37 > wherein the cyclic ketal has a carbon number of 20 or less.

The additive for molding of < 39 > according to < 37 > or < 38 >, wherein the cyclic ketal compound comprises a compound represented by the following general formula (1).

[ Chemical formula 9]

The additive for molding according to < 40 > to < 37 > or < 38 >, wherein the cyclic ketal compound comprises a compound represented by the following general formula (2).

[ Chemical 10]

The additive for molding of < 41 > according to < 39 > or < 40 > wherein, in the general formulae (1) and (2), R1 and R2 are at least 1 selected from the group consisting of R1 is methyl, R2 is methyl, R1 is methyl, R2 is ethyl, R1 is methyl, R2 is hydrogen, R1 is ethyl, and R2 is ethyl.

The additive for molding according to any one of < 39 > < 41 >, wherein 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.

Examples

Hereinafter, embodiments and the like specifically showing the present invention will be described.

< Evaluation method of raw Material >)

[ 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 sample was neutralized by adding ion-exchanged water to the same weight and adding 0.1 mass% of H2SO 4. The precipitate thus formed was isolated by filtration, washed with water and dried. This was dissolved in tetrahydrofuran to prepare a sample for GPC.

(B) Column: 1 of the protection columns TSX (manufactured by Toyo Sedum Co., ltd.) was used, 1 of the protection columns TSK3000HXL (7.8 mm. Phi. Times.30 cm), and 1 of the protection columns TSK2500HXL (7.8 mm. Phi. Times.30 cm) were used. The connection was made from the injection port side in the order of protection column-3000 HXL-2500 HXL.

(C) Standard substance: monodisperse polystyrene having a known weight-average molecular weight (manufactured by Toyo Cao industries Co., ltd.)

(D) Eluent: THF (flow rate: 1cm ³/min)

(E) Column temperature: 25 DEG C

(F) A detector: ultraviolet spectrophotometer (quantification at the wavelength of the maximum peak of ultraviolet absorption of phenol)

(G) Segmentation method for molecular weight calculation: time division (2 seconds)

[ Average particle diameter ]

(In the case of particles of 53 μm or more)

The particle diameter of 50% by mass was measured using a sieve of 850, 600, 425, 300, 212, 150, 106, 75, 53 μm based on JIS Z2601 (1993) 'test method for foundry sand' specified in appendix 2, and the mass-cumulative particle diameter was set as the average particle diameter.

(In the case of particles smaller than 53 μm)

The average particle diameter was 50% of the volume cumulative average particle diameter measured by a laser diffraction particle size distribution measuring apparatus (LA-920 manufactured by horiba, ltd.). The analysis conditions are as follows.

Measurement method: flow (flow) method

Dispersion medium: ion exchange water

Dispersion method: stirring and internally placing ultrasonic waves for 3 minutes

Sample concentration: 2mg/100cc

Preparation of aqueous phenolic resin solution

In a2 liter glass vessel equipped with a thermometer and a stirrer, 380g of phenol, 670g of 48 mass% aqueous potassium hydroxide solution, 165g of water, and 265g of 92% paraformaldehyde were mixed and reacted at 85℃to obtain an aqueous phenolic resin solution. The solid content concentration of the aqueous phenolic resin solution was 63.9 mass%. The weight average molecular weight (Mw) of the water-soluble phenol resin was 1820.

Examples 1 to 16 and comparative examples 1 to 14 >

[ Preparation of adhesive composition ]

74 Parts by mass of the above aqueous phenolic resin solution (47.3 parts by mass of phenolic resin), 3 parts by mass of sodium aluminate, 6 parts by mass of sodium tetraborate 10 hydrate (borax), 1 part by mass of 3-glycidoxypropyl trimethoxysilane (KBM-403 manufactured by Xinyue chemical industry Co., ltd.) and the compounds shown in Table 1 were mixed together in predetermined amounts, and then water was mixed so as to obtain 100 parts by mass of the adhesive composition.

[ Refractory particles ]

Silica sand ("Sanhe silica sand R No. 6", sanhe silica Co., ltd.) was used as the refractory particles. The average particle diameter was 181. Mu.m.

[ Preparation of sample for evaluation of residual mold compressive Strength ]

In a kitchen mixer ("KENMIX. AICOH. CHEF", manufactured by Kagaku Co., ltd.) equipped with an aluminum mixer stirring blade, 30 parts by mass of the binder composition was charged to 1000 parts by mass of refractory particles, and the mixture was mixed at 300rpm for 2 minutes, followed by filling the mixture into a 50 mm. Times.50 mm. Phi. Wood pattern for test pieces. Thereafter, carbon dioxide was introduced at 25℃at a flow rate of 2.5L/min for 30 seconds to obtain a test piece for evaluation. The test piece was left standing at 25℃for 24 hours, and then an aluminum foil ("Myfoil" manufactured by UACJ) was wound so as to cover the entire surface, and then heated in an electric furnace heated to 200℃for 1 hour. Thereafter, the mixture was allowed to stand at 25℃for 1 hour. Thereafter, the aluminum foil was removed to obtain a sample for evaluating the compressive strength of the residual mold.

[ Method for evaluating residual mold compression Strength ]

The residual mold compressive strength was calculated from the load at the time of fracture by evaluating a sample for residual mold compressive strength evaluation at a speed of 5 mm/sec using a compressive strength evaluation tester ("SDW 2000SH model", manufactured by Kogyo Co., ltd.). In addition, the mold compression strength of the test piece after standing at 25℃for 24 hours was also measured. The results are shown in tables 1 and 2. The smaller the difference between the residual mold compression strength (a) and the mold compression strength (B), the more suppressed the increase in the residual mold compression strength, and the better the mold disintegrability.

TABLE 1

TABLE 2

As is clear from table 1, the binder compositions of examples 1 to 5 have smaller differences between the residual mold compression strength (a) and the mold compression strength (B) than the binder compositions of comparative example 2 and comparative examples 4 to 14, and are suppressed in the increase in the residual mold compression strength and excellent in the mold disintegration property. In addition, the difference between the residual mold compression strength (a) and the mold compression strength (B) of the adhesive compositions of comparative examples 1 and 3 was small, but the mold compression strength after standing at 25 ℃ for 24 hours was low, and was not practical.

As is clear from Table 2, the binder compositions of examples 6 to 16 containing alcohol improved the mold compression strength, and the difference between the residual mold compression strength (A) and the mold compression strength (B) was also small.

Examples 17 to 21 >

In a kitchen mixer ("KENMIX. AICOH. CHEF", manufactured by Kagaku Co., ltd.) equipped with an aluminum mixer stirring blade, 30 parts by mass of the binder composition of example 10 and 3 parts by mass of the inorganic particles shown in Table 4 were charged to 1000 parts by mass of the refractory particles, and the mixture was mixed at 300rpm for 2 minutes, and then the mixture was filled into a 50 mm. Times.50 mm. Phi. Wood mold for test pieces. Thereafter, carbon dioxide was introduced at 25℃at a flow rate of 2.5L/min for 30 seconds to obtain a test piece for evaluation. The same evaluation as in example 10 was performed using the obtained test piece for evaluation. The results are shown in Table 3. The properties of the inorganic particles used are shown in Table 4.

TABLE 3

TABLE 4

From the above results, it is found that by containing inorganic particles in the mold composition, the difference between the residual mold compressive strength (a) and the mold compressive strength (B) is smaller, and the improvement of the residual mold compressive strength is suppressed, and the mold disintegrating property is excellent.

Claims

1. A binder composition for mold molding, which comprises a phenolic resin and a cyclic ketal compound having a hydroxyl group and having 5 or more carbon atoms, wherein the cyclic ketal compound comprises a compound represented by the following general formula (1),

In the general formula (1), R1 and R2 each represent hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, R3 and R4 each represent hydrogen or a-CH ₂ OH group, but R3 and R4 are not simultaneously hydrogen.

2. The binder composition for mold shaping according to claim 1, wherein the content of the cyclic ketal compound in the binder composition for mold shaping is 0.2 mass% or more and 30 mass% or less.

3. The binder composition for mold shaping according to claim 1 or 2, wherein the content of the cyclic ketal compound in the binder composition for mold shaping is 0.2 mass% or more and 20 mass% or less.

4. The binder composition for mold shaping 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 phenolic resin.

5. The binder composition for mold shaping according to claim 1 or 2, 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 phenolic resin.

6. The binder composition for mold shaping according to claim 1 or 2, wherein the cyclic ketal compound has a carbon number of 20 or less.

7. The binder composition for mold shaping according to claim 1 or 2, wherein in the general formula (1), R1 and R2 are 1 or more selected from the group consisting of R1 is methyl and R2 is methyl, R1 is methyl and R2 is ethyl, R1 is methyl and R2 is hydrogen, R1 is ethyl and R2 is ethyl.

8. The binder composition for mold shaping according to claim 1 or 2, wherein the content of the compound represented by the general formula (1) in the cyclic ketal is 80 mass% or more.

9. The binder composition for mold molding according to claim 1 or 2, further comprising an alcohol containing 1 or more selected from the group consisting of a polyhydric alcohol, a glycol ether, an alicyclic glycol compound and an aromatic alcohol.

10. The binder composition for mold molding according to claim 9, wherein the content of 1 or more selected from the group consisting of polyhydric alcohols, glycol ethers, alicyclic glycol compounds and aromatic compound alcohols in the alcohol is 80% by mass or more.

11. The binder composition for mold shaping according to claim 9, wherein the content of the cyclic ketal compound in the binder composition for mold shaping is 0.2 mass% or more and 18 mass% or less.

12. The binder composition for mold shaping according to claim 9, wherein the content of the alcohol in the binder composition for mold shaping is 0.5 mass% or more and 15 mass% or less.

13. The binder composition for mold shaping according to claim 9, wherein the content of the cyclic ketal compound is 0.5 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the phenolic resin.

14. The binder composition for mold molding according to claim 9, wherein the alcohol content is 1 part by mass or more and 40 parts by mass or less per 100 parts by mass of the phenolic resin.

15. The binder composition for mold shaping according to claim 9, wherein a total content of the cyclic ketal compound and the alcohol is 1 mass% or more and 20 mass% or less in the binder composition for mold shaping.

16. The binder composition for mold shaping according to claim 9, wherein a total content of the cyclic ketal compound and the alcohol is 2 parts by mass or more and 40 parts by mass or less per 100 parts by mass of the phenolic resin.

17. The binder composition for mold shaping according to claim 9, wherein a ratio of a content of the cyclic ketal compound to a total content of the alcohol and the cyclic ketal compound is 0.1 or more and 0.8 or less.

18. A method for producing a mold, comprising: a mixing step of mixing refractory particles with the binder composition for mold molding according to any one of claims 1 to 17 to obtain a composition for mold molding; and a curing step of filling the composition for mold molding into a mold and curing the composition for mold molding.

19. The method for producing a mold according to claim 18, wherein the curing agent used for curing the composition for molding a mold in the curing step is an organic ester compound or carbon dioxide.

20. A composition for molding comprising the binder composition for molding according to any one of claims 1 to 17 and refractory particles.

21. The composition for molding of claim 20, 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.

22. A composition for molding comprising a phenolic resin, a cyclic ketal compound having a hydroxyl group and having 5 or more carbon atoms, and refractory particles, wherein the cyclic ketal compound comprises a compound represented by the following general formula (1),

23. The composition for molding of any one of claims 20 to 22, wherein the phenolic resin is contained in an amount of 5 to 80 parts by mass inclusive with respect to 1000 parts by mass of the refractory particles.

24. The composition for molding according to any one of claims 20 to 22, wherein the content of the cyclic ketal compound is 0.5 parts by mass or more and 65 parts by mass or less based on 100 parts by mass of the phenolic resin.

25. The composition for molding according to any one of claims 20 to 22, wherein the content of the cyclic ketal compound is 0.5 parts by mass or more and 40 parts by mass or less based on 100 parts by mass of the phenolic resin.

26. The composition for molding according to any one of claims 20 to 22, further comprising inorganic particles having an average particle diameter of 0.1 μm to 50 μm.

27. The composition for molding of claim 26, 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 phenolic resin.

28. An additive for molding, which comprises a cyclic ketal compound having a hydroxyl group and having 5 or more carbon atoms, wherein the cyclic ketal compound comprises a compound represented by the following general formula (1),

29. The additive for molding according to claim 28, wherein the content of the compound represented by the general formula (1) in the cyclic ketal is 80 mass% or more.