Binder composition for making casting molds

Abstract

To provide a binder composition for molding a mold, which can improve the final strength of the mold.SOLUTION: A binder composition for mold making, comprising: an acid-curable resin; and at least one surfactant selected from the group consisting of a nonionic surfactant and an anionic surfactant, wherein the nonionic surfactant comprises a glycol ether compound represented by the following general formula (I), and the anionic surfactant comprises an organic sulfate compound represented by the following general formula (II): R1-O - (AO) m-H (I) R2 - O - (AO) n - SO3M (II) SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a binder composition for mold making. [Background technology]

[0002] Generally, acid-curing molds are produced by supplying a foundry binder composition and a foundry hardener composition to a kneader through a pipe using a supply device, mixing them with refractory particles, and then filling a wooden or other master mold with the resulting mixed sand and curing the acid-curing resin. Examples of acid-curing resins include furan resins and phenolic resins. Furan resins include furfuryl alcohol-urea-formaldehyde resins, furfuryl alcohol-formaldehyde resins, furfuryl alcohol-phenol-formaldehyde resins, and other known modified furan resins. Such mold production methods allow for a high degree of freedom in molding operations and, due to the excellent thermal properties of the molds, can produce high-quality castings. Therefore, they are widely used in the casting of machine parts, construction machinery parts, automotive parts, and other castings.

[0003] Improving the strength of a mold is an important issue in making a mold and using the mold to cast a desired casting. The final strength of the mold is particularly important when producing large molds, and if the mold strength is insufficient, the mold may crack or the core may break during casting, which may pose a danger to workers or result in a defective casting.

[0004] Patent Document 1 discloses that high mold strength can be obtained by mixing an aromatic dialdehyde with an acid-hardening resin.

[0005] Patent Document 2 discloses that high mold strength can be obtained by using an acid-curing mold binder composition obtained by mixing or reacting an acid-curing resin with a compound having one or more aldehyde groups in the molecule, which is obtained from a sugar or starch. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 57-124543 [Patent Document 2] Japanese Patent Publication No. 61-235034 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the acid-setting mold binder compositions and the like disclosed in Patent Documents 1 and 2, the target mixtures have relatively low solubility in acid-setting resins such as furan resins, and therefore further improvement in the final strength of molds has been desired.

[0008] The present invention provides a binder composition for molding a foundry mold that can improve the final strength of the mold. [Means for solving the problem]

[0009] The present invention provides A binder composition for foundry molding, comprising an acid-hardening resin and one or more surfactants selected from a nonionic surfactant and an anionic surfactant, The nonionic surfactant contains a glycol ether compound represented by the following general formula (I): The binder composition for mold formation contains an organic sulfate ester salt compound represented by the following general formula (II) as the anionic surfactant. R 1 -O-(AO)mH (I) [In general formula (I), R 1 represents a linear or branched alkyl or alkenyl group having from 8 to 18 carbon atoms, AO represents an oxyalkylene group in which A is an alkanediyl group having from 2 to 3 carbon atoms, and m is the average number of moles of oxyalkylene groups added, which is from 1 to 15. R 2 -O-(AO)n-SO3M (II) [In the formula, R 2represents a linear or branched alkyl or alkenyl group having from 8 to 18 carbon atoms, AO represents an oxyalkylene group in which A is an alkanediyl group having from 2 to 3 carbon atoms, n is the average number of moles of oxyalkylene groups added and is a number of from 0 to 5, and M represents an alkali metal, an alkaline earth metal, ammonium, or an organic ammonium. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a binder composition for foundry molding that can improve the final strength of the mold. DETAILED DESCRIPTION OF THE INVENTION

[0011] <Binder composition for mold making> The binder composition for foundry molding of this embodiment (hereinafter also simply referred to as a binder composition) is a binder composition for foundry molding containing an acid-hardening resin and one or more surfactants selected from a nonionic surfactant and an anionic surfactant, The nonionic surfactant contains a glycol ether compound represented by the following general formula (I): The anionic surfactant contains an organic sulfate ester salt compound represented by the following general formula (II). R 1 -O-(AO)mH (I) [In general formula (I), R 1 represents a linear or branched alkyl or alkenyl group having from 8 to 18 carbon atoms, AO represents an oxyalkylene group in which A is an alkanediyl group having from 2 to 3 carbon atoms, and m is the average number of moles of oxyalkylene groups added, which is from 1 to 15. R 2 -O-(AO)n-SO3M (II) [In the formula, R 2represents a linear or branched alkyl or alkenyl group having from 8 to 18 carbon atoms, AO represents an oxyalkylene group in which A is an alkanediyl group having from 2 to 3 carbon atoms, n is the average number of moles of oxyalkylene groups added and is a number of from 0 to 5, and M represents an alkali metal, an alkaline earth metal, ammonium, or an organic ammonium. The binder composition of this embodiment can improve the final strength of the mold. The reason why the binder composition of this embodiment has such an effect is not clear, but is thought to be as follows.

[0012] It is believed that the surfactant reduces the surface tension of the binder composition, improving the wettability of the binder composition to the refractory particles, thereby increasing the contact area between the refractory particles and the acid-curing resin and the adhesion points between the refractory particles themselves, thereby improving the mold strength.

[0013] [Acid-curable resin] The acid-hardening resin may be any known resin. Examples of the acid-hardening resin include one or more selected from the group consisting of furan resin, condensates of melamine and aldehydes, and condensates of urea and aldehydes. The acid-hardening resin preferably contains a furan resin, from the viewpoints of improving the hardening rate of the mold and improving the strength of the mold.

[0014] The furan resin is obtained by polymerizing a monomer composition containing furfuryl alcohol, and can be used without any particular limitation as long as it can be used as a binder for mold making. Examples of the furan resin include one or more selected from the group consisting of furfuryl alcohol, condensates of furfuryl alcohol, condensates of furfuryl alcohol and aldehydes, condensates of furfuryl alcohol and urea, condensates of furfuryl alcohol, phenols and aldehydes, condensates of furfuryl alcohol, melamine and aldehydes, and condensates of furfuryl alcohol, urea and aldehydes (urea-modified furan resin), as well as co-condensates of two or more selected from the group.

[0015] From the viewpoint of improving the mold curing rate and mold strength, the furan resin is preferably one or more selected from the group consisting of furfuryl alcohol, condensates of furfuryl alcohol and aldehydes, condensates of furfuryl alcohol and urea, condensates of furfuryl alcohol, phenols and aldehydes, condensates of furfuryl alcohol, melamine and aldehydes, and condensates of furfuryl alcohol, urea and aldehydes, as well as one or more selected from the group consisting of co-condensates of two or more selected from the above group. From the viewpoint of the global environment, furfuryl alcohol, which can be produced from plants, which are non-petroleum resources, is preferred.

[0016] Examples of the aldehydes include formaldehyde, acetaldehyde, glyoxal, furfural, terephthalaldehyde, hydroxymethylfurfural, etc., and one or more of these can be used as appropriate. From the viewpoint of improving mold strength, it is preferable to use formaldehyde, and from the viewpoint of reducing the amount of formaldehyde generated during molding, it is preferable to use furfural, terephthalaldehyde, or hydroxymethylfurfural.

[0017] Examples of the phenols include phenol, cresol, resorcinol, bisphenol A, bisphenol C, bisphenol E, and bisphenol F, and one or more of these can be used.

[0018] The furan resin can be produced by a known method. For example, when the furan resin is a urea-modified furan resin, the urea-modified furan resin can be obtained by reacting 100 parts by mass of furfuryl alcohol with 0.6 to 30 parts by mass of urea and 0.4 to 50 parts by mass of paraformaldehyde.

[0019] The content of the furan-cured resin in the acid-curable resin is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more, from the viewpoint of improving mold strength. The content of the furan resin in the acid-curable resin is preferably 100% by mass or less, from the viewpoint of reducing viscosity. The content of the furan-cured resin in the acid-curable resin is preferably 50% by mass or more and 100% by mass or less, more preferably 70% by mass or more and 100% by mass or less, and even more preferably 90% by mass or more and 100% by mass or less, from the viewpoint of improving mold strength and reducing viscosity.

[0020] The content of the acid-curing resin in the binder composition is preferably 65% ​​by mass or more, more preferably 70% by mass or more, and even more preferably 75% by mass or more, from the viewpoint of improving mold strength. The content of the acid-curing resin in the binder composition is preferably 98% by mass or less, more preferably 95% by mass or less, and even more preferably 90% by mass or less, from the viewpoint of reducing viscosity. The content of the acid-curing resin in the binder composition is preferably 65% ​​by mass or more and 98% by mass or less, more preferably 70% by mass or more and 95% by mass or less, and even more preferably 75% by mass or more and 90% by mass or less, from the viewpoint of improving mold strength and reducing viscosity.

[0021] [Surfactant] The surfactant contains at least one selected from nonionic surfactants and anionic surfactants from the viewpoint of improving the final strength of the mold.

[0022] [Nonionic surfactants] The nonionic surfactant can be any known surfactant without any particular limitation. Examples of the nonionic surfactant include polyoxyalkylene alkyl ether, polyoxyalkylene alkenyl ether, polyoxyethylene distyrenated phenyl ether, higher fatty acid sucrose ester, polyglycerin fatty acid ester, higher fatty acid mono- or diethanolamide, polyoxyethylene hydrogenated castor oil, polyoxyethylene fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbit fatty acid ester, alkyl saccharide, alkyl glyceryl ether, alkyl polyglucoside, etc. These may be used alone or in combination of two or more.

[0023] From the viewpoint of improving the final strength of the mold, the nonionic surfactant contains a glycol ether compound represented by the following general formula (I). R 1 -O-(AO)mH (I) [In general formula (I), R 1 represents a linear or branched alkyl or alkenyl group having from 8 to 18 carbon atoms, AO represents an oxyalkylene group in which A is an alkanediyl group having from 2 to 3 carbon atoms, and m is the average number of moles of oxyalkylene groups added, which is from 1 to 15.

[0024] R in the general formula (I) 1 From the viewpoint of improving the final strength of the mold, the number of carbon atoms in R is preferably 8 or more, more preferably 10 or more, and even more preferably 12 or more, and from the same viewpoint, it is preferably 18 or less, more preferably 16 or less, and even more preferably 14 or less. 1 The number of carbon atoms in the alkyl group is preferably 8 or more and 18 or less, more preferably 10 or more and 16 or less, and even more preferably 12 or more and 14 or less, from the viewpoint of improving the final strength of the mold.

[0025] AO in the general formula (I) may be one type of alkyleneoxy group or may contain two or more types of alkyleneoxy groups. From the viewpoint of improving solubility in the binder composition, AO in the general formula (I) is preferably one or more types selected from an ethyleneoxy group and a propyleneoxy group, and more preferably contains an ethyleneoxy group.

[0026] From the viewpoint of improving the final strength of the mold, m in the general formula (I) is preferably 1 or more, more preferably 2 or more, and from the same viewpoint, it is preferably 15 or less, more preferably 12 or less, even more preferably 9 or less, and still more preferably 4 or less. From the viewpoint of improving the final strength of the mold, m in the general formula (I) is preferably 1 or more and 15 or less, more preferably 2 or more and 12 or less, and even more preferably 2 or more and 9 or less.

[0027] From the viewpoint of improving the final strength of the mold, the content of the glycol ether compound represented by the general formula (I) in the nonionic surfactant is preferably 50% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and still more preferably 100% by mass.

[0028] [Anionic surfactants] The anionic surfactant may be any known surfactant without any particular limitation. Examples of the anionic surfactant include alkylbenzenesulfonates, alkyl or alkenyl ether sulfates, alkyl or alkenyl sulfates, olefinsulfonates, alkanesulfonates, saturated or unsaturated fatty acid salts, alkyl or alkenyl ether carboxylates, α-sulfofatty acid salts, N-acylamino acid salts, mono- or di-phosphate esters, and sulfosuccinate esters. These surfactants may be used alone or in combination of two or more.

[0029] The anionic surfactant contains an organic sulfate ester salt compound represented by the following general formula (II) from the viewpoint of improving the final strength of the mold. R 2 -O-(AO)n-SO3M (II) [In general formula (II), R 2 represents a linear or branched alkyl or alkenyl group having from 8 to 18 carbon atoms, AO represents an oxyalkylene group in which A is an alkanediyl group having from 2 to 3 carbon atoms, n is the average number of moles of oxyalkylene groups added and is a number of from 0 to 5, and M represents an alkali metal, an alkaline earth metal, ammonium, or an organic ammonium.

[0030] R in the general formula (II) 2 From the viewpoint of improving the final strength of the mold, the number of carbon atoms in R is preferably 8 or more, more preferably 9 or more, even more preferably 10 or more, and even more preferably 11 or more, and from the same viewpoint, it is preferably 18 or less, more preferably 15 or less, and even more preferably 12 or less. 2 From the viewpoint of improving the final strength of the mold, the number of carbon atoms is preferably 8 or more and 18 or less, more preferably 9 or more and 15 or less, even more preferably 10 or more and 12 or less, and still more preferably 11 or more and 12 or less.

[0031] In the general formula (II), AO may be one type of alkyleneoxy group or may contain two or more types of alkyleneoxy groups. From the viewpoint of improving solubility in the binder composition, AO in the general formula (II) is preferably one or more types selected from an ethyleneoxy group and a propyleneoxy group, and more preferably contains an ethyleneoxy group.

[0032] In the general formula (II), n is preferably 0 or more, more preferably 1 or more, and even more preferably 2 or more from the viewpoint of improving the final strength of the mold, and from the same viewpoint, n is preferably 5 or less, more preferably 4 or less, and even more preferably 3 or less. In the general formula (II), n is preferably 0 or more and 5 or less, more preferably 1 or more and 4 or less, and even more preferably 2 or more and 3 or less from the viewpoint of improving the final strength of the mold.

[0033] In the general formula (II), M represents an alkali metal, an alkaline earth metal, ammonium, or an organic ammonium, and is preferably an alkali metal, more preferably sodium, from the viewpoint of improving solubility in the binder composition.

[0034] From the viewpoint of improving the final strength of the mold, the content of the organic sulfate ester salt compound represented by the general formula (II) in the anionic surfactant is preferably 50% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and still more preferably 100% by mass.

[0035] From the viewpoint of improving the final strength of the mold, the total content of the nonionic surfactant and the anionic surfactant in the surfactant is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 100% by mass.

[0036] From the viewpoint of improving the final strength of the mold, the content of the surfactant in the binder composition is preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, and even more preferably 1.0 part by mass or more, relative to 100 parts by mass of the acid-curing resin. From the viewpoint of improving the final strength of the mold, the content of the surfactant in the binder composition is preferably 10 parts by mass or less, more preferably 5.0 parts by mass or less, and even more preferably 2.0 parts by mass or less, relative to 100 parts by mass of the acid-curing resin. From the viewpoint of improving the final strength of the mold, the content of the surfactant in the binder composition is preferably 0.1 part by mass or more and 10 parts by mass or less, more preferably 0.5 parts by mass or more and 5.0 parts by mass or less, and even more preferably 1.0 part by mass or more and 2.0 parts by mass or less, relative to 100 parts by mass of the acid-curing resin.

[0037] From the viewpoint of improving the final strength of the mold, the content of the surfactant in the binder composition is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1.0% by mass or more. From the viewpoint of improving the final strength of the mold, the content of the surfactant in the binder composition is preferably 10% by mass or less, more preferably 5.0% by mass or less, and even more preferably 2.0% by mass or less. From the viewpoint of improving the final strength of the mold, the content of the surfactant in the binder composition is preferably 0.1% by mass or more and 10% by mass or less, more preferably 0.5% by mass or more and 5.0% by mass or less, and even more preferably 1.0% by mass or more and 2.0% by mass or less.

[0038] [Curing accelerator] The binder composition may contain a hardening accelerator to improve mold strength. Specific examples and amounts of the hardening accelerator are described in WO 2015 / 098642.

[0039] 〔water〕 The binder composition may further contain water. For example, when producing various condensates, such as a condensate of furfuryl alcohol and aldehydes, the raw materials are used in aqueous solution form, or condensation water is generated, so the condensate is usually obtained in the form of a mixture with water. When using such a condensate in the binder composition, the water may be removed by topping, if necessary, but it is not necessary to remove it during production as long as the curing reaction rate can be maintained. Furthermore, water may be further added to the binder composition for the purpose of adjusting the viscosity of the binder composition to an easy-to-handle value. When water is further added to adjust the viscosity of the binder composition to an easy-to-handle value, the viscosity of the binder composition (at 25°C) is preferably 70 mPa·s or less, and more preferably 50 mPa·s or less, from the viewpoint of workability during mold production. When the binder composition contains water, the content of water in the binder composition is preferably 1% by mass or more, and more preferably 5% by mass or more, from the viewpoint of adjusting the viscosity of the binder composition to an easy-to-handle level, and is preferably 50% by mass or less, and more preferably 40% by mass or less, and even more preferably 30% by mass or less, from the viewpoint of improving the strength of the mold.

[0040] [Silane coupling agent] The binder composition may further contain additives such as a silane coupling agent. For example, the binder composition preferably contains a silane coupling agent, since this can further improve the final strength of the mold. Specific examples of silane coupling agents include those described in International Publication No. 2015 / 098642. From the viewpoint of improving the strength of the mold, preferred silane coupling agents include aminosilanes such as N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltriethoxysilane, and 3-aminopropyltrimethoxysilane, with N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane being more preferred. The content of the silane coupling agent in the binder composition is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, from the viewpoint of improving the final strength of the mold. From the same viewpoint, the content of the silane coupling agent in the binder composition is preferably 0.5% by mass or less, and more preferably 0.3% by mass or less.

[0041] The binder composition is suitable for use in the production of self-hardening molds. Here, a self-hardening mold is a mold in which, when the binder composition and a hardener are mixed with sand, a polymerization reaction progresses over time, resulting in hardening of the mold. The temperature of the sand used in this process is in the range of -20°C to 50°C, and preferably 0°C to 40°C. By selecting an appropriate amount of hardener for the sand at such a temperature and adding it to the sand, the mold can be properly hardened.

[0042] From the viewpoint of improving the final strength of the mold, the surface tension of the binder composition is preferably 40 mN / m or less, more preferably 37 mN / m or less, and even more preferably 34 mN / m or less. From the viewpoint of improving the ejection stability of the binder composition, the surface tension of the binder composition is preferably 26 mN / m or more, more preferably 29 mN / m or more, and even more preferably 32 mN / m or more. From the viewpoint of improving the final strength of the mold and the ejection stability of the binder composition, the surface tension of the binder composition is preferably 26 mN / m or more and 40 mN / m or less, more preferably 29 mN / m or more and 37 mN / m or less, and even more preferably 32 mN / m or more and 34 mN / m or less.

[0043] <Mold making composition> The foundry molding composition of this embodiment contains the binder composition and a curing agent that cures the acid-curing resin contained in the binder composition, and has the same effects as the binder composition.

[0044] [Curing agent] The curing agent can be any curing agent that can cure the binder composition without any particular limitation. Examples of the curing agent include acid-based curing agents, and one or more of conventionally known curing agents can be used, such as sulfonic acid compounds such as xylenesulfonic acid (particularly m-xylenesulfonic acid), toluenesulfonic acid (particularly p-toluenesulfonic acid), and methanesulfonic acid, phosphoric acid, phosphoric acid compounds such as acidic phosphate esters, and sulfuric acid.

[0045] From the viewpoint of ease of handling, the curing agent may be used in the form of a curing agent composition containing water, one or more solvents selected from the group consisting of alcohols, ether alcohols, and esters.

[0046] The content of the curing agent in the curing agent composition is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more from the viewpoint of improving the final strength of the mold. The content of the curing agent in the curing agent composition is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 80% by mass or less from the viewpoint of dissolving the curing agent.

[0047] The mass ratio of the binder composition to the curing agent is preferably 10 to 60 parts by mass of the curing agent per 100 parts by mass of the binder composition, from the viewpoint of improving the curing speed and the final strength of the mold.

[0048] <Mold composition> The foundry composition of this embodiment contains refractory particles, the binder composition, and the curing agent, and has the same effects as the binder composition.

[0049] [Fire-resistant particles] The refractory particles may be one or more of conventionally known refractory particles such as silica sand, chromite sand, zircon sand, olivine sand, alumina sand, mullite sand, synthetic mullite sand, etc., or may be recovered or recycled used refractory particles. Of these, silica sand is preferred.

[0050] In the mold composition, the mass ratio of the refractory particles, the binder composition, and the hardener can be appropriately set. From the viewpoint of improving the hardening rate and the final strength of the mold, it is preferable that the binder composition is in the range of 0.5 to 1.5 parts by mass and the hardener is in the range of 0.07 to 1 part by mass per 100 parts by mass of the refractory particles.

[0051] <Mold manufacturing method> The binder composition can be used to manufacture molds.

[0052] [First embodiment] The method for producing a mold of the first embodiment includes a mixing step of mixing the refractory particles, the binder composition, and the hardener to obtain the mold composition, and a hardening step of filling a mold with the mold composition and hardening the mold composition. The method for producing a mold has the same effects as the method for producing the binder composition.

[0053] In the mixing step, the order in which the binder composition, the curing agent, and the refractory particles are added and mixed is not particularly limited. The binder composition and the curing agent may be mixed to produce the mold-making composition, and then the mold-making composition and the refractory particles may be mixed. Alternatively, the binder composition, the curing agent, and the refractory particles may be added and mixed separately. However, from the viewpoints of storage stability and mold productivity, it is preferable to mix the binder composition, the curing agent, and the refractory particles to obtain the mold-making composition. Furthermore, from the viewpoint of improving the final mold strength, it is preferable to add the curing agent to the refractory particles and mix them, and then add the binder composition and mix them. Furthermore, when two or more curing agents are used, the respective curing agents may be mixed and then added, or each curing agent may be added separately.

[0054] The contents of the respective components in the binder composition, the foundry molding composition, and the foundry molding composition can be considered to be the blending amounts of the respective components in the binder composition, the foundry molding composition, and the foundry molding composition.

[0055] In the mixing step, the raw materials can be mixed using a known general method, for example, a method in which the raw materials are added and kneaded using a batch mixer, or a method in which the raw materials are supplied to a continuous mixer and kneaded.

[0056] In the mold manufacturing method of this embodiment, the mold can be manufactured by utilizing the conventional mold manufacturing process as is, except for the mixing step.

[0057] Second Embodiment The method for producing a mold according to the second embodiment includes a mixing step of mixing the refractory particles, the acid-curing resin, the curing agent, and the surfactant to obtain a mold composition, and a curing step of filling a mold with the mold composition and curing the mold composition. This mold production method has the same effects as the binder composition.

[0058] In the mixing step, the order in which the refractory particles, the acid-hardening resin, the curing agent, and the surfactant are added and mixed is not particularly limited. However, it is preferable to first mix the acid-hardening resin and the surfactant to form a mixture, and then mix the mixture with the refractory particles and the curing agent to obtain a mold composition. Furthermore, from the viewpoint of improving the final strength of the mold, it is preferable to add the curing agent to the refractory particles and mix them, and then add the mixture of the binder composition and the surfactant and mix them. Furthermore, when two or more curing agents are used, the respective curing agents may be mixed and then added, or each curing agent may be added separately.

[0059] The content of each component in the foundry composition can be considered as the blending amount of each component in the foundry composition.

[0060] In the mixing step, the raw materials can be mixed using a known general method, for example, a method in which the raw materials are added and kneaded using a batch mixer, or a method in which the raw materials are supplied to a continuous mixer and kneaded.

[0061] In the mold manufacturing method of this embodiment, the mold can be manufactured by utilizing the conventional mold manufacturing process as is, except for the mixing step. [Example]

[0062] <Methods for measuring physical properties> [Water content] Measurement was carried out using an automatic moisture measuring device (Hiranuma Sangyo Co., Ltd., AQV-2200A) based on the Karl Fischer method specified in JIS K 0068.

[0063] [Surface tension of binder composition for foundry molding] An automatic surface tensiometer (DY-200) manufactured by Kyowa Interface Science Co., Ltd. was used to automatically measure the surface tension by the Wilhelmy method.

[0064] <Examples and Comparative Examples> [Production of furan resin composition] 100 parts by mass of furfuryl alcohol, 35 parts by mass of paraformaldehyde, and 13 parts by mass of urea were mixed in a three-neck flask and adjusted to pH 9 with a 25% by mass aqueous solution of sodium hydroxide. The reaction mixture was heated to 100°C and reacted at the same temperature for 1 hour. The pH was adjusted to 4.5 with 37% by mass hydrochloric acid and further reacted at 100°C for 1 hour. The pH was then adjusted to 7 with a 25% by mass aqueous solution of sodium hydroxide, and 5 parts by mass of urea was added. The reaction was continued at 100°C for 30 minutes to obtain a furan resin composition containing a furan resin (urea-modified furan resin). The composition of the furan resin composition was 76.3% by mass of urea-modified furan resin, 15.3% by mass of furfuryl alcohol, and 8.5% by mass of water.

[0065] [Preparation of Binder Composition] Furfuryl alcohol, water, a silane coupling agent, and various surfactants were added to the furan resin composition and mixed to obtain the compositions shown in Table 1, thereby obtaining binder compositions for mold formation according to Examples 1 to 7 and Comparative Examples 1 and 2. The components shown in Table 1 were as follows: Polyoxyethylene (2) alkyl (C12-14) ether: DEHYDOL LS2 manufactured by Thai Ethoxylate Co., Ltd. Polyoxyethylene (5) alkyl (C12-14) ether: DEHYDOL LS5 manufactured by Thai Ethoxylate Co., Ltd. Polyoxyethylene (7) alkyl (C12-14) ether: DEHYDOL LS7 manufactured by Thai Ethoxylate Co., Ltd. Polyoxyethylene (9) alkyl (C12-14) ether: DEHYDOL LS9 manufactured by Thai Ethoxylate Co., Ltd. Sodium decyl sulfate: EMAL 3F manufactured by Kao Corporation Sodium lauryl sulfate: EMAL 24D manufactured by Kao Corporation Polyoxyethylene (2) lauryl ether sodium sulfate: Kao Corporation Sodium dodecylbenzenesulfonate: Kao Corporation, Neopelex G-25, 25% aqueous solution

[0066] <Evaluation method> [Evaluation of compressive strength of mold] Under conditions of 25°C and 55% RH, 0.40 parts by mass of a hardener composition (Kao Lightner C-17, manufactured by Kao-Quaker Corporation) was added to 100 parts by mass of furan reclaimed silica sand, followed by 0.8 parts by mass of a binder composition obtained by adding and mixing the components shown in Table 1 in predetermined amounts. The mixture was then mixed to obtain foundry compositions according to each Example and Comparative Example. The resulting foundry compositions were filled into cylindrical test piece frames measuring 50 mm in diameter and 50 mm in height. After 2 hours, the frames were demolded. 24 hours after filling, the compressive strength (MPa) was measured according to the method described in JIS Z 2604-1976. The evaluation results are shown in Table 1.

[0067] [Table 1]

Claims

1. A binder composition for foundry molding, comprising an acid-hardening resin and one or more surfactants selected from a nonionic surfactant and an anionic surfactant, The nonionic surfactant contains a glycol ether compound represented by the following general formula (I): The binder composition for mold formation, wherein the anionic surfactant contains an organic sulfate ester salt compound represented by the following general formula (II): R １ -O-(AO)m-+ (-) [In general formula (I), R １ represents a linear or branched alkyl or alkenyl group having from 8 to 18 carbon atoms, AO represents an oxyalkylene group in which A is an alkanediyl group having from 2 to 3 carbon atoms, and m is the average number of moles of oxyalkylene groups added, which is a number of from 1 to 15. R ２ -O-(AO).-O ３ M (-I) [In the formula, R ２ represents a linear or branched alkyl or alkenyl group having from 8 to 18 carbon atoms, AO represents an oxyalkylene group in which A is an alkanediyl group having from 2 to 3 carbon atoms, n is the average number of moles of oxyalkylene groups added and is a number of from 0 to 5, and M represents an alkali metal, an alkaline earth metal, ammonium, or an organic ammonium.

2. 2. The binder composition for mold formation according to claim 1, wherein the content of the surfactant is 0.1 parts by mass or more and 10 parts by mass or less per 100 parts by mass of the acid-curing resin.

3. 2. The binder composition for mold formation according to claim 1, wherein the content of the surfactant is 0.1% by mass or more and 10% by mass or less.

4. 2. The binder composition for mold formation according to claim 1, wherein the content of the glycol ether compound represented by general formula (I) in the nonionic surfactant is 50% by mass or more and 100% by mass or less.

5. 2. The binder composition for mold formation according to claim 1, wherein the content of the organic sulfate ester salt compound represented by general formula (II) in the anionic surfactant is 50% by mass or more and 100% by mass or less.

6. 2. The binder composition for mold formation according to claim 1, which has a surface tension of 40 mN / m or less.

7. 2. The binder composition for mold formation according to claim 1, wherein the acid-curable resin contains a furan resin.

8. 8. The binder composition for mold formation according to claim 7, wherein the content of the furan-curing resin in the acid-curing resin is 50% by mass or more and 100% by mass or less.

9. A composition for mold formation, comprising the binder composition for mold formation according to any one of claims 1 to 8 and a curing agent that cures the acid-curing resin contained in the binder composition for mold formation.

10. A foundry composition comprising refractory particles, the binder composition for foundry formation according to any one of claims 1 to 8, and a curing agent that cures the acid-curing resin contained in the binder composition for foundry formation.

11. A method for manufacturing a mold, comprising: a mixing step of mixing refractory particles, the binder composition for mold formation according to any one of claims 1 to 8, and a curing agent that cures an acid-curable resin contained in the binder composition for mold formation to obtain a foundry composition; and a curing step of filling a form with the foundry composition and curing the foundry composition.

12. A method for manufacturing a mold, comprising: a mixing step of mixing refractory particles, an acid-hardening resin, a curing agent for curing the acid-hardening resin, and one or more surfactants selected from a nonionic surfactant and an anionic surfactant to obtain a foundry composition; and a curing step of filling a mold with the foundry composition and curing the foundry composition, The nonionic surfactant contains a glycol ether compound represented by the following general formula (I): The binder composition for mold formation, wherein the anionic surfactant contains an organic sulfate ester salt compound represented by the following general formula (II): R １ -O-(AO)m-+ (-) [In the formula, R １ represents a linear or branched alkyl or alkenyl group having from 8 to 18 carbon atoms, AO represents an oxyalkylene group in which A is an alkanediyl group having from 2 to 3 carbon atoms, and m is the average number of moles of oxyalkylene groups added, which is a number of from 1 to 15. R ２ -O-(AO).-O ３ M (-I) [In the formula, R ２ represents a linear or branched alkyl or alkenyl group having from 8 to 18 carbon atoms, AO represents an oxyalkylene group in which A is an alkanediyl group having from 2 to 3 carbon atoms, n is the average number of moles of oxyalkylene groups added and is a number of from 0 to 5, and M represents an alkali metal, an alkaline earth metal, ammonium, or an organic ammonium.

13. A use of a binder composition for foundry molding, which contains an acid-hardening resin and one or more surfactants selected from a nonionic surfactant and an anionic surfactant, for producing a foundry mold, comprising: The nonionic surfactant contains a glycol ether compound represented by the following general formula (I): The anionic surfactant contains an organic sulfate ester salt compound represented by the following general formula (II): R １ -O-(AO)m-+ (-) [In general formula (I), R １ represents a linear or branched alkyl or alkenyl group having from 8 to 18 carbon atoms, AO represents an oxyalkylene group in which A is an alkanediyl group having from 2 to 3 carbon atoms, and m is the average number of moles of oxyalkylene groups added, which is a number of from 1 to 15. R ２ -O-(AO).-O ３ M (-I) [In the formula, R ２ represents a linear or branched alkyl or alkenyl group having from 8 to 18 carbon atoms, AO represents an oxyalkylene group in which A is an alkanediyl group having from 2 to 3 carbon atoms, n is the average number of moles of oxyalkylene groups added and is a number of from 0 to 5, and M represents an alkali metal, an alkaline earth metal, ammonium, or an organic ammonium.

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