Binder composition for mold molding

Abstract

The mold forming binder composition of the present application contains a basic phenol resin, an imidazole compound represented by the following formula (1), and water. According to the present application, a mold forming binder composition and a mold forming composition having excellent storage stability, which suppresses thickening during storage and deterioration of fluidity and filling property of the mold forming composition, can be provided. (In the general formula (1), R 1 , R 2 , R 3 , and R 4 each independently represent hydrogen or a hydrocarbon group having 1 or more and 4 or less carbon atoms.)

Description

Technical Field

[0001] This invention relates to an adhesive composition for molding. Background Technology

[0002] There are known molding methods that use phenolic resin as a binder and cure the phenolic resin using organic esters, carbon dioxide, or amine gas. For example, in Japanese Patent Application Publication No. 2006-192477, an organic binder for molding phenolic carbamate-based gas-curing molds or self-curing molds is described as containing phenolic resin, polyisocyanate compounds, organic solvents, and specific organic nitrogen compounds, with the aim of achieving excellent mold strength (initial strength).

[0003] If phenolic resin-containing binders are left for extended periods, the phenolic resin thickens, leading to decreased storage stability. This results in problems such as reduced metering accuracy when automatically supplied by pumps, uneven mixing, decreased flowability of the mold-making composition containing refractory particles and binders, and poor filling properties into the mold. Poor filling properties of the mold-making composition can cause unevenness on the surface of the resulting mold, reduced surface strength of the mold, and casting defects such as sand inclusions, sand adhesion, penetrating sand adhesion, and rat tails in the resulting castings.

[0004] Regarding the aforementioned issue, Japanese Patent Application Publication No. 2000-15389 discloses a carbon dioxide curing adhesive composition that uses a mixture of water-soluble phenolic resin and cyclic urea compound, with the aim of improving the surface stability of the mold and suppressing the thickening of the adhesive while maintaining high mold strength. Summary of the Invention

[0005] The present invention is a molding binder composition containing an alkaline phenolic resin, an imidazole compound as shown in formula (1) below, and water.

[0006] [Chemistry 1]

[0007]

[0008] (In the above general formula (1), R) 1 R 2 R 3 and R 4 Each can independently represent hydrogen or a hydrocarbon group with 1 or more but less than 4 carbon atoms. Detailed Implementation

[0009] The technology described in Japanese Patent Application Publication No. 2000-15389 does not sufficiently improve storage stability by inhibiting the thickening of the binder.

[0010] The present invention provides a mold-forming binder composition with excellent storage stability that inhibits thickening during storage, inhibits the deterioration of the flowability and filling properties of the mold-forming composition, and a method for manufacturing a mold.

[0011] The present invention is a molding binder composition containing an alkaline phenolic resin, an imidazole compound as shown in formula (1) below, and water.

[0012] [Chemistry 2]

[0013]

[0014] (In the above general formula (1), R) 1 R 2 R 3 and R 4 Each can independently represent hydrogen or a hydrocarbon group with 1 or more but less than 4 carbon atoms.

[0015] According to the present invention, a mold-forming binder composition, a mold-forming composition, and a method for manufacturing a mold can be provided that have excellent storage stability, suppress thickening during storage, suppress deterioration of the flowability and filling properties of the mold-forming composition, and suppress thickening during storage.

[0016] Hereinafter, one embodiment of the present invention will be described.

[0017] <Binder Composition for Casting Molding>

[0018] The mold-forming adhesive composition of this embodiment (hereinafter also referred to as the adhesive composition) is a mold-forming adhesive composition containing an alkaline phenolic resin, an imidazole compound as shown in formula (1) below, and water.

[0019] [Chemistry 3]

[0020]

[0021] (In the above general formula (1), R) 1 R 2 R 3 and R 4 Each can independently represent hydrogen or a hydrocarbon group with 1 or more but less than 4 carbon atoms.

[0022] The binder composition according to this embodiment provides a binder composition with excellent storage stability that inhibits thickening during storage, especially during storage at high temperatures (e.g., 50°C), inhibits the deterioration of the flowability and filling properties of the molding composition. The reason why the binder composition of this embodiment achieves this effect is not certain, but can be considered as follows.

[0023] It is believed that the thickening of basic phenolic resin during storage is due to the condensation between hydroxymethyl groups. Therefore, it can be argued that by coordinating imidazole compounds with small stereostructures and lone pairs of electrons on the nitrogen atom to the hydroxymethyl groups, the condensation between hydroxymethyl groups can be suppressed.

[0024] [Alkaline phenolic resin]

[0025] The aforementioned alkaline phenolic resins are generally products obtained by polycondensation of phenolic and aldehyde compounds under alkaline conditions. The phenolic compounds can be one or a mixture of two or more, including phenol, bisphenol A, bisphenol F, cresol, 3,5-xylenol, resorcinol, catechol, nonylphenol, p-tert-butylphenol, isopropenylphenol, phenylphenol, and other substituted phenols; and mixtures of various phenolic compounds such as cashew nut shell extract. The aldehyde compounds can be one or a mixture of two or more, including formaldehyde, acetaldehyde, furfural, and glyoxal. These compounds can be used in aqueous solution as needed. Additionally, monomers capable of condensing with aldehyde compounds, such as urea, melamine, and cyclohexanone, can also be mixed in; monobasic aliphatic alcohols such as methanol, ethanol, isopropanol, n-propanol, and butanol; water-soluble polymers such as polyacrylates; cellulose derivatives; polyvinyl alcohol; and lignin derivatives.

[0026] Examples of alkaline catalysts used in the synthesis of the aforementioned alkaline phenolic resins include alkali metal hydroxides such as LiOH, NaOH, and KOH, with NaOH and / or KOH being particularly preferred. Furthermore, these alkaline catalysts can be mixed into the binder composition. The amount of alkali metal hydroxide is preferably 0.01 to 6 moles relative to 1 mole of phenol, and more preferably 0.5 to 2.5 moles.

[0027] Generally, the above-mentioned basic phenolic resin is used in the form of an aqueous solution. From the viewpoint of improving mold strength, the content of basic phenolic resin in the above-mentioned basic phenolic resin aqueous solution (the solid mass of the above-mentioned basic phenolic resin aqueous solution after drying at 105°C for 3 hours) is preferably 30% by mass or more, more preferably 50% by mass or more. From the viewpoints of improving mold strength and improving operability, the content of basic phenolic resin in the above-mentioned basic phenolic resin aqueous solution is preferably 85% by mass or less, more preferably 75% by mass or less. Furthermore, from the viewpoints of improving mold strength and improving operability, the content of basic phenolic resin in the above-mentioned basic phenolic resin aqueous solution is preferably 30 to 85% by mass, more preferably 50 to 75% by mass.

[0028] From the viewpoint of improving mold strength, the weight-average molecular weight (Mw) of the aforementioned basic phenolic resin is preferably 500 or more, more preferably 800 or more, and even more preferably 1200 or more. From the viewpoints of improving mold strength and improving operability, the weight-average molecular weight (Mw) of the basic phenolic resin is preferably 8000 or less, more preferably 5000 or less, and even more preferably 3000 or less. Furthermore, from the viewpoints of improving mold strength and improving operability, the weight-average molecular weight (Mw) of the aforementioned basic phenolic resin is preferably 500 to 8000, more preferably 800 to 5000, and even more preferably 1200 to 3000. It should be noted that the weight-average molecular weight of the basic phenolic resin was determined using the method described in the examples.

[0029] From the viewpoint of improving mold strength, the content of the alkaline phenolic resin in the above-mentioned binder composition is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, and even more preferably 40% by mass or more. From the viewpoint of suppressing thickening of the binder composition during storage and improving the flowability of the mold-forming composition, the content of the alkaline phenolic resin in the above-mentioned binder composition is preferably 70% by mass or less, more preferably 60% by mass or less, even more preferably 55% by mass or less, even more preferably 53% by mass or less, even more preferably 52% by mass or less, even more preferably 50% by mass or less, even more preferably 49% by mass or less, even more preferably 48% by mass or less, and even more preferably 46% by mass or less. Furthermore, from the viewpoints of improving mold strength, suppressing thickening of the binder composition during storage, and improving the flowability of the mold-forming composition, the content of the alkaline phenolic resin in the binder composition is preferably 10-70% by mass, more preferably 20-60% by mass, even more preferably 30-60% by mass, even more preferably 40-60% by mass, even more preferably 40-55% by mass, even more preferably 40-53% by mass, even more preferably 40-52% by mass, even more preferably 40-50% by mass, even more preferably 40-49% by mass, even more preferably 40-48% by mass, and even more preferably 40-46% by mass.

[0030] [Imidazole compounds]

[0031] From the viewpoint of inhibiting thickening of the adhesive composition during storage, the above-mentioned imidazole compound contains R in the above general formula (1). 1 Compounds that represent hydrogen or hydrocarbon groups with 1 or more but less than 4 carbon atoms.

[0032] From the viewpoint of inhibiting thickening of the adhesive composition during storage, the above-mentioned imidazole compound contains R in the above general formula (1).2 Compounds that represent hydrogen or a hydrocarbon group having 1 or more but less than 4 carbon atoms, preferably compounds that represent hydrogen or a hydrocarbon group having 1 or more but less than 2 carbon atoms.

[0033] From the viewpoint of inhibiting thickening of the adhesive composition during storage, the above-mentioned imidazole compound contains R in the above general formula (1). 3 Compounds that represent hydrogen or a hydrocarbon group having 1 or more but less than 4 carbon atoms, preferably representing hydrogen or a hydrocarbon group having 1 or more but less than 2 carbon atoms, and more preferably representing hydrogen or a methyl group.

[0034] From the viewpoint of inhibiting thickening of the adhesive composition during storage, the above-mentioned imidazole compound contains R in the above general formula (1). 4 Compounds that represent hydrogen or a hydrocarbon group having 1 or more but less than 4 carbon atoms, preferably representing hydrogen or methyl, more preferably representing hydrogen.

[0035] From the viewpoint of inhibiting thickening of the binder composition during storage and improving the flowability of the composition for molding, the above-mentioned imidazole compound contains R in the above general formula (1). 1 R 2 R 3 and R 4 The compound having a total carbon number of 8 or less, more preferably 7 or less, further preferably 6 or less, even more preferably 5 or less, even more preferably 4 or less, even more preferably 3 or less, even more preferably 2 or less, even more preferably 1 or less, and even more preferably 0.

[0036] Specific examples of the aforementioned imidazole compounds include one or more selected from imidazole, 1-methylimidazolium, 1,2-dimethylimidazolium, 2-ethylimidazolium, 2-ethyl-4-methylimidazolium, 1-isobutyl-2-methylimidazolium, 1-isopropylimidazolium, 2-isopropylimidazolium, 1-tert-butylimidazolium, 1-propylimidazolium, 2-propylimidazolium, 1-vinylimidazolium, 1,2,4,5-tetramethylimidazolium, 1-butylimidazolium, 2-butylimidazolium, 1-ethylimidazolium, 2-methyl-1-vinylimidazolium, 1-allylimidazolium, 4-methylimidazolium, and 4-ethylimidazolium. From the viewpoint of suppressing thickening of the binder composition during storage and improving the flowability of the composition for molding, the imidazole compound preferably contains one or more selected from imidazole, 1-methylimidazole, 1,2-dimethylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, and 1-isobutyl-2-methylimidazole; more preferably, it contains one or more selected from imidazole, 1-methylimidazole, 1,2-dimethylimidazole, 2-ethylimidazole, and 2-ethyl-4-methylimidazole; even more preferably, it contains one or more selected from imidazole, 1-methylimidazole, 1,2-dimethylimidazole, and 2-ethylimidazole; even more preferably, it contains one or more selected from imidazole, 1-methylimidazole, and 1,2-dimethylimidazole; even more preferably, it contains imidazole and / or 1-methylimidazole; and even more preferably, it contains imidazole. Furthermore, from the viewpoint of availability, the imidazole compound preferably contains imidazole and / or 2-ethyl-4-methylimidazole.

[0037] From the viewpoint of suppressing thickening of the binder composition during storage and improving the flowability of the composition for molding, the content of the imidazole compound in the binder composition is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, even more preferably 0.7% by mass or more, even more preferably 2% by mass or more, even more preferably 4% by mass or more, even more preferably 7% by mass or more, even more preferably 9% by mass or more, and even more preferably 13% by mass or more. From the viewpoint of improving mold strength, the content of the imidazole compound in the binder composition is preferably 30% by mass or less, more preferably 25% by mass or less, even more preferably 20% by mass or less, and even more preferably 17% by mass or less. Furthermore, from the viewpoints of suppressing thickening of the binder composition during storage, improving the flowability of the mold-forming composition, and improving mold strength, the content of the imidazole compound in the binder composition is preferably 0.1 to 30% by mass, more preferably 0.1 to 25% by mass, even more preferably 0.1 to 20% by mass, even more preferably 0.1 to 17% by mass, even more preferably 0.7 to 17% by mass, even more preferably 2 to 17% by mass, even more preferably 4 to 17% by mass, even more preferably 7 to 17% by mass, even more preferably 9 to 17% by mass, and even more preferably 13 to 17% by mass.

[0038] From the viewpoint of suppressing thickening of the binder composition during storage and improving the flowability of the composition for molding, the content of the imidazole compound in the binder composition relative to 100 parts by weight of the alkaline phenolic resin is preferably 0.2 parts by weight or more, more preferably 1 part by weight or more, further preferably 4 parts by weight or more, even more preferably 8 parts by weight or more, even more preferably 14 parts by weight or more, even more preferably 20 parts by weight or more, and even more preferably 27 parts by weight or more. From the viewpoint of improving mold strength, the content of the imidazole compound in the binder composition relative to 100 parts by weight of the alkaline phenolic resin is preferably 60 parts by weight or less, more preferably 50 parts by weight or less, further preferably 45 parts by weight or less, even more preferably 40 parts by weight or less, and even more preferably 35 parts by weight or less. Furthermore, from the viewpoints of suppressing thickening of the binder composition during storage, improving the fluidity of the composition for molding, and increasing the strength of the mold, the content of the imidazole compound in the binder composition relative to 100 parts by weight of the alkaline phenolic resin is preferably 0.2 to 60 parts by weight, more preferably 0.2 to 50 parts by weight, even more preferably 0.2 to 45 parts by weight, even more preferably 0.2 to 40 parts by weight, even more preferably 0.2 to 35 parts by weight, even more preferably 1 to 35 parts by weight, even more preferably 4 to 35 parts by weight, even more preferably 8 to 35 parts by weight, even more preferably 14 to 35 parts by weight, even more preferably 20 to 35 parts by weight, and even more preferably 27 to 35 parts by weight.

[0039] 〔water〕

[0040] From the viewpoints of suppressing thickening of the binder composition during storage and improving the fluidity of the composition for mold making, the water content in the binder composition is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 25% by mass or more. From the viewpoints of improving mold strength, suppressing thickening of the binder composition during storage, and improving the fluidity of the composition for mold making, the water content in the binder composition is preferably 60% by mass or less, more preferably 50% by mass or less, even more preferably 45% by mass or less, and even more preferably 40% by mass or less. Furthermore, from the viewpoints of suppressing thickening of the binder composition during storage, improving the fluidity of the composition for mold making, and improving mold strength, the water content in the binder composition is preferably 10 to 60% by mass, more preferably 20 to 50% by mass, even more preferably 25 to 45% by mass, and even more preferably 25 to 40% by mass.

[0041] [Other ingredients]

[0042] The above-described adhesive composition may further include additives such as silane coupling agents, aluminates, and oxyanionic compounds to a degree that does not impair the effectiveness of this embodiment.

[0043] [Silane coupling agent]

[0044] From the viewpoint of improving mold strength, the above-mentioned binder composition preferably contains a silane coupling agent. Examples of such silane coupling agents include γ-(2-amino)propylmethyldimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and N-β-(aminoethyl)γ-aminopropylmethyldimethoxysilane. From the viewpoint of improving mold strength, the content of the above-mentioned silane coupling agent in the binder composition is preferably 0.1 to 5% by mass, more preferably 0.3 to 1% by mass.

[0045] [Aluminate]

[0046] From the viewpoint of improving mold strength, the above-mentioned binder composition preferably contains an aluminate. Examples of the aluminate include alkali metal salts of aluminic acid. From the viewpoint of improving mold strength, sodium aluminate is preferred. From the viewpoint of improving mold strength, the content of the aluminate in the above-mentioned binder composition is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more. From the viewpoint of improving mold strength, the content of the aluminate in the above-mentioned binder composition is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less. Furthermore, from the viewpoint of improving mold strength, the content of the aluminate in the above-mentioned binder composition is preferably 0.1 to 10% by mass, more preferably 0.5 to 5% by mass, and even more preferably 1 to 3% by mass.

[0047] [Oxygen-containing anionic compounds]

[0048] When using carbon dioxide to cure the above-mentioned adhesive composition, from the viewpoints of improving mold strength and increasing mold curing speed, it is preferable to contain an oxygen-containing anionic compound. This is because it is believed that the oxygen-containing anionic compound absorbs carbon dioxide to form an ionomer, thereby polymerizing the basic phenolic resin. Examples of such oxygen-containing anionic compounds include boric acid and borates. Examples of borates include sodium tetraborate decahydrate (borax), potassium tetraborate decahydrate, sodium metaborate, sodium pentaborate, and potassium pentaborate. From the viewpoints of improving mold strength and increasing mold curing speed, sodium tetraborate decahydrate (borax) is preferred.

[0049] From the viewpoints of improving mold strength and improving mold curing speed, the content of the oxygen-containing anionic compound in the above-mentioned adhesive composition is preferably 1% by mass or more, more preferably 3% by mass or more, further preferably 5% by mass or more, and even more preferably 6% by mass or more. From the viewpoints of improving mold strength and improving the flowability of the mold-forming composition, the content of the oxygen-containing anionic compound in the above-mentioned adhesive composition is preferably 30% by mass or less, more preferably 20% by mass or less, further preferably 15% by mass or less, and even more preferably 10% by mass or less. Furthermore, from the viewpoints of improving mold strength, improving mold curing speed, and improving the flowability of the mold-forming composition, the content of the oxygen-containing anionic compound in the above-mentioned adhesive composition is preferably 1 to 30% by mass, more preferably 3 to 20% by mass, further preferably 5 to 15% by mass, and even more preferably 6 to 10% by mass.

[0050] From the viewpoints of improving mold strength and improving mold curing speed, the total content of boric acid compounds in the above-mentioned oxygen-containing anionic compounds is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 100% by mass.

[0051] From the viewpoints of improving mold strength and improving mold curing speed, the total content of boric acid and borate in the above-mentioned oxygen-containing anionic compound is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 100% by mass.

[0052] From the viewpoints of improving mold strength and improving mold curing speed, the content of borax in the above-mentioned oxygen-containing anionic compound is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 100% by mass.

[0053] <Mold Manufacturing Method>

[0054] In the mold manufacturing method of this embodiment, the mold can be manufactured directly using existing mold manufacturing processes. As a preferred mold manufacturing method, a mold manufacturing method is provided, which includes: a mixing step, in which at least refractory particles and the above-mentioned binder composition are mixed to obtain a mold molding composition; and a curing step, in which the above-mentioned mold molding composition is filled into a mold box and the mold molding composition is cured.

[0055] [Mixed Process]

[0056] [Refractory Particles]

[0057] The refractory particles that can be used in the mold manufacturing method of this embodiment include conventionally known refractory particles such as silica sand, chromite sand, zircon sand, olivine sand, alumina sand, mullite sand, synthetic mullite sand, and alumina spherical sand. Alternatively, recycled sand obtained by recovering and regenerating used refractory particles can also be used. It should be noted that two or more types of refractory particles can be used alone or in combination.

[0058] From the viewpoints of improving mold strength and economy, the average particle size of the aforementioned refractory particles is preferably greater than 50 μm, more preferably 70 μm or more, further preferably 120 μm or more, and even more preferably 150 μm or more. From the same viewpoint, it is preferably 600 μm or less, more preferably 400 μm or less, further preferably 300 μm or less, and even more preferably 250 μm or less. It should be noted that in this specification, the average particle size is determined using the method described in the examples.

[0059] In the above mixing process, as a method for mixing the raw materials, a known general method can be used, such as a method of mixing by adding the raw materials using an intermittent mixer or a method of mixing by supplying the raw materials to a continuous mixer.

[0060] The ratio of the aforementioned refractory particles to the aforementioned binder composition can be appropriately set. From the viewpoints of improving mold strength and economy, the content of the binder composition relative to 1000 parts by weight of the aforementioned refractory particles is preferably 5 parts by weight or more, more preferably 10 parts by weight or more, and preferably 100 parts by weight or less, more preferably 80 parts by weight or less, further preferably 50 parts by weight or less, and even more preferably 40 parts by weight or less. Furthermore, relative to 1000 parts by weight of the aforementioned refractory particles, the alkaline phenolic resin is preferably 3 parts by weight or more, more preferably 5 parts by weight or more, and preferably 80 parts by weight or less, more preferably 50 parts by weight or less, further preferably 30 parts by weight or less, and even more preferably 25 parts by weight or less.

[0061] In the above mixing process, when obtaining the composition for molding, the imidazole compound may be further mixed in addition to the binder composition. In this case, the content of the imidazole compound in the composition for molding is preferably within the range of the imidazole compound content relative to 100 parts by weight of the basic phenolic resin.

[0062] Alternatively, a composition for molding can be obtained by mixing a binder composition containing refractory particles, the above-mentioned alkaline phenolic resin aqueous solution but excluding the above-mentioned imidazole compound, and the above-mentioned imidazole compound. In this case, the amount of the above-mentioned imidazole compound is the same as the amount described in the binder composition.

[0063] Alternatively, a molding composition can be obtained by separately mixing the refractory particles, the aqueous solution of basic phenolic resin, the imidazole compound described above, and other components used in the binder composition. In this case, the content of basic phenolic resin is preferably 3 parts by mass or more, and more preferably 80 parts by mass or less, relative to 1000 parts by mass of the refractory particles. Furthermore, the proportions of the imidazole compound and other components used in the binder composition described above are the same as those described in the binder composition.

[0064] When the imidazole compound is mixed in addition to the binder composition as described above, the imidazole compound is a molding additive. The molding additive of this embodiment contains the imidazole compound. The preferred embodiment of the imidazole compound in the molding additive of the present invention is the same as the preferred embodiment of the imidazole compound in the binder composition described above.

[0065] [Curing process]

[0066] In the above-described curing process, the molding composition is filled into the mold box, and the molding composition is then cured. Commonly known methods can be used to cure the molding composition. One example of curing the molding composition is using a curing agent. Examples of such curing agents include organic ester compounds and carbon dioxide.

[0067] As the aforementioned organic ester compounds, lactones with 3 to 10 carbon atoms, organic esters formed from mono- or polyols with 1 to 10 carbon atoms and organic carboxylic acids with 1 to 10 carbon atoms, or alkylene carbonates with 1 to 8 carbon atoms can be used alone or in combination. In self-curing molding methods, γ-butyrolactone, propiolactone, ε-caprolactone, ethyl formate, ethylene glycol diacetate, ethylene glycol monoacetate, triacetin, ethylene carbonate, and propylene carbonate are preferred. In gas-curing molding methods using organic esters, methyl formate is preferred.

[0068] When using an organic ester as the curing agent, from the viewpoints of improving mold strength, improving curing speed, and economy, the amount of organic ester relative to 100 parts by mass of the above-mentioned adhesive composition is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, and preferably 35 parts by mass or less, more preferably 30 parts by mass or less.

[0069] When using an organic ester as the curing agent, from the viewpoints of improving mold strength, improving curing speed, and economy, the amount of organic ester relative to 100 parts by weight of phenolic resin is preferably 20 parts by weight or more, more preferably 30 parts by weight or more, and preferably 70 parts by weight or less, more preferably 60 parts by weight or less.

[0070] When using carbon dioxide as the curing agent, from the viewpoint of improving mold strength, the flow rate of carbon dioxide is [value missing] per 100 cm³. 3 In the molding process, the flow rate is preferably 0.2 L / min or more, more preferably 1 L / min or more, further preferably 5 L / min or more, even more preferably 10 L / min or more, and even more preferably 15 L / min or more. From an economic point of view, per 100 cm³ 3 In the molding process, the flow rate is preferably 30 L / min or less, more preferably 25 L / min or less. Regarding the carbon dioxide flow time, from the viewpoint of improving mold strength, it is preferably 10 seconds or more, more preferably 20 seconds or more, and even more preferably 25 seconds or more. From an economic viewpoint, it is preferably 90 seconds or less, more preferably 70 seconds or less, even more preferably 50 seconds or less, and even more preferably 40 seconds or less. Regarding the curing temperature, from the viewpoint of improving mold strength, it is preferably -5°C or higher, more preferably 5°C or higher, and even more preferably 10°C or higher. From an economic viewpoint, it is preferably 45°C or lower, more preferably 40°C or lower, and even more preferably 35°C or lower.

[0071] When using carbon dioxide as the curing agent, from the viewpoints of improving mold strength, improving curing speed, and economy, the amount of carbon dioxide relative to 100 parts by mass of the above-mentioned adhesive composition is preferably 25 parts by mass or more, more preferably 30 parts by mass or more, and preferably 100 parts by mass or less, more preferably 75 parts by mass or less.

[0072] When using carbon dioxide as the curing agent, from the viewpoints of improving mold strength, improving curing speed, and economy, the amount of carbon dioxide relative to 100 parts by mass of alkaline phenolic resin is preferably 50 parts by mass or more, more preferably 60 parts by mass or more, and preferably 200 parts by mass or less, more preferably 150 parts by mass or less.

[0073] <Molding Composition>

[0074] The molding composition of this embodiment contains the above-mentioned refractory particles and the above-mentioned binder composition. That is, the molding composition of this embodiment contains the above-mentioned refractory particles, the above-mentioned basic phenolic resin, and the above-mentioned imidazole compound.

[0075] The content of the above-mentioned binder composition relative to the above-mentioned refractory particles is as described in the mixing process of the above-mentioned mold manufacturing method.

[0076] The content of the aforementioned basic phenolic resin relative to the refractory particles is as described in the mixing process of the aforementioned mold manufacturing method. Furthermore, the content of the aforementioned imidazole compound relative to the aforementioned basic phenolic resin is as described in the aforementioned adhesive composition.

[0077] Regarding the above-described embodiments, the present invention further discloses the following embodiments.

[0078] <1>

[0079] A molding adhesive composition comprising an alkaline phenolic resin, an imidazole compound as shown in formula (1), and water.

[0080] [Chemistry 4]

[0081]

[0082] (In the above general formula (1), R) 1 R 2 R 3 and R 4 Each can independently represent hydrogen or a hydrocarbon group with 1 or more but less than 4 carbon atoms.

[0083] <2>

[0084] According to the adhesive composition for molding of molds described in <1>, the content of the imidazole compound in the adhesive composition for molding of molds is 0.1% by mass or more and 30% by mass or less.

[0085] <3>

[0086] According to the adhesive composition for molding of molds described in <1> or <2>, the content of the imidazole compound in the adhesive composition for molding of molds is 0.1% by mass or more and 17% by mass or less.

[0087] <4>

[0088] According to any one of <1> to <3>, the content of the imidazole compound in the above-mentioned mold-making adhesive composition relative to 100 parts by weight of the above-mentioned basic phenolic resin is 0.2 parts by weight or more and 60 parts by weight or less.

[0089] <5>

[0090] According to any one of <1> to <4>, the content of the imidazole compound in the above-mentioned mold-making adhesive composition relative to 100 parts by weight of the above-mentioned basic phenolic resin is 0.2 parts by weight or more and 35 parts by weight or less.

[0091] <6>

[0092] According to any one of <1> to <5>, the mold-forming adhesive composition comprises, wherein the imidazole compound represented by formula (1) above includes one or more selected from imidazole, 1-methylimidazolium, 1,2-dimethylimidazolium, 2-ethylimidazolium, 2-ethyl-4-methylimidazolium and 1-isobutyl-2-methylimidazolium.

[0093] <7>

[0094] According to any one of <1> to <6>, the content of the alkaline phenolic resin in the above-mentioned mold-making adhesive composition is 10% by mass or more and 70% by mass or less.

[0095] <8>

[0096] According to any one of <1> to <7>, the content of the alkaline phenolic resin in the above-mentioned mold-making adhesive composition is 40% by mass or more and 60% by mass or less.

[0097] <9>

[0098] According to any one of <1> to <8>, the adhesive composition for molding a mold is wherein the water content in the adhesive composition is 25% by mass or more and 40% by mass or less.

[0099] <10>

[0100] The mold-making adhesive composition described in any one of <1> to <9> contains an oxygen-containing anionic compound.

[0101] <11>

[0102] According to the mold-making binder composition described in <10>, the aforementioned oxygen-containing anionic compound contains a boric acid compound.

[0103] <12>

[0104] According to the mold-making binder composition described in <10> or <11>, the content of boric acid compound in the above-mentioned oxygen-containing anionic compound is 95% by mass or more.

[0105] <13>

[0106] According to any one of <10> to <12>, the content of the oxygen-containing anionic compound in the above-mentioned mold-forming adhesive composition is 1% by mass or more and 30% by mass or less.

[0107] <14>

[0108] According to any one of <10> to <13>, the content of the oxygen-containing anionic compound in the above-mentioned mold-making adhesive composition is 6% by mass or more and 10% by mass or less.

[0109] <15> A molding adhesive composition according to any one of <1> to <14>, which is used for carbon dioxide curing.

[0110] <16>

[0111] A method for manufacturing a mold, comprising: a mixing step, wherein refractory particles and a mold-forming binder composition described in any one of <1> to <14> are mixed to obtain a mold-forming composition; and a curing step, wherein the mold-forming composition is filled into a mold box and the mold-forming composition is cured.

[0112] <17>

[0113] According to the method for manufacturing a mold as described in <16>, it comprises: a mixing step, in which refractory particles and a mold-forming binder composition described in any one of <1> to <14> are mixed to obtain a mold-forming composition; and a curing step, in which the mold-forming composition is filled into a mold box and the mold-forming composition is cured using carbon dioxide.

[0114] <18>

[0115] A composition for molding a mold, comprising a binder composition for molding a mold as described in any one of <1> to <15> and refractory particles.

[0116] <19>

[0117] A molding composition comprising an alkaline phenolic resin, an imidazole compound as shown in formula (1) below, and refractory particles.

[0118] [Chemistry 5]

[0119]

[0120] (In the above general formula (1), R) 1 R 2 R 3 and R 4Each can independently represent hydrogen or a hydrocarbon group with 1 or more but less than 4 carbon atoms.

[0121] <20>

[0122] According to the mold-making composition described in <18> or <19>, the content of the alkaline phenolic resin in the mold-making composition is 3 parts by mass or more and 80 parts by mass or less relative to 1000 parts by mass of the refractory particles.

[0123] <21>

[0124] According to any one of <18> to <20>, the composition for molding a mold is wherein the content of the alkaline phenolic resin in the composition for molding a mold is 3 parts by mass or more and 25 parts by mass or less relative to 1000 parts by mass of the refractory particles.

[0125] <22>

[0126] According to any one of <18> to <21>, the composition for molding a mold is wherein the content of the imidazole compound in the composition for molding a mold is 0.2 parts by mass or more and 60 parts by mass or less relative to 100 parts by mass of the alkaline phenolic resin.

[0127] <23>

[0128] According to any one of <18> to <22>, the composition for molding a mold is wherein the content of the imidazole compound in the composition for molding a mold is 0.2 parts by mass or more and 35 parts by mass or less relative to 100 parts by mass of the alkaline phenolic resin.

[0129] <24>

[0130] According to any one of <18> to <23>, the mold-making composition wherein the imidazole compound represented by formula (1) above contains one or more selected from imidazole, 1-methylimidazolium, 1,2-dimethylimidazolium, 2-ethylimidazolium, 2-ethyl-4-methylimidazolium and 1-isobutyl-2-methylimidazolium.

[0131] <25>

[0132] The molding composition described in any one of <18> to <23> is used for carbon dioxide curing.

[0133] Example

[0134] Hereinafter, specific embodiments of the present invention will be described.

[0135] <Methods for evaluating raw materials>

[0136] [Weight-average molecular weight (Mw) of basic phenolic resin]

[0137] The weight-average molecular weight (Mw) of basic phenolic resins was determined by GPC (gel permeation chromatography) under the following conditions.

[0138] (a) Sample preparation: Add the same weight of ion-exchanged water to the sample, and neutralize with 0.1% by mass of H2SO4. Filter the resulting precipitate, wash with water, and dry. Dissolve it in tetrahydrofuran (THF) to prepare the sample for GPC.

[0139] (b) Chromatographic columns: Use one TSX (Toyo Soda Industries, Ltd.) HXL (6.5mm φ × 4cm) guard column, one TSK3000HXL (7.8mm φ × 30cm) guard column, and one TSK2500HXL (7.8mm φ × 30cm) guard column. Connect the columns in the order of guard column - 3000HXL - 2500HXL from the injection port side.

[0140] (c) Standard material: Monodisperse polystyrene with known weight-average molecular weight (manufactured by Toyo Soda Industries, Ltd.)

[0141] (d) Eluent: THF (flow rate: 1 cm⁻¹) 3 / min)

[0142] (e) Column temperature: 25℃

[0143] (f) Detector: Ultraviolet spectrophotometer (for quantification at the wavelength of the maximum ultraviolet absorption peak of phenol).

[0144] (g) Segmentation method for calculating molecular weight: time segmentation (2 seconds)

[0145] [Average Particle Size]

[0146] (For particles larger than 53μm)

[0147] Based on the method specified in Appendix 2 of JIS Z2601 (1993) "Test Methods for Casting Sand", the test was performed using sieves of 850, 600, 425, 300, 212, 150, 106, 75, and 53 μm, and the particle size of 50% by mass was set as the average particle size.

[0148] (For particles smaller than 53 μm)

[0149] The average particle size at 50% volumetric density was measured using a laser diffraction particle size distribution measuring device (Horiba Manufacturing Co., Ltd. LA-920). The analytical conditions are shown below.

[0150] • Measurement method: Flow method

[0151] • Dispersion medium: Ion-exchanged water

[0152] • Dispersion method: Stirring, followed by internal ultrasonication for 3 minutes

[0153] • Sample concentration: 2 mg / 100 cc

[0154] <Preparation of Alkaline Phenolic Resin Aqueous Solution>

[0155] In a 2-liter glass container equipped with a thermometer and a stirrer, 380.0 g of phenol, 666.3 g of 48% potassium hydroxide aqueous solution, 297.3 g of water, and 263.7 g of 92% paraformaldehyde were mixed and reacted at 85°C to obtain an aqueous solution of alkaline phenolic resin. The solid content of the aqueous solution of alkaline phenolic resin was 58.6% by mass. Furthermore, the weight-average molecular weight (Mw) of this alkaline phenolic resin was 1820.

[0156] <Example 1-1>

[0157] [Preparation of adhesive composition]

[0158] The adhesive composition of Example 1-1 was obtained by using 80.7 parts by weight of the above-mentioned alkaline phenolic resin aqueous solution (47.3 parts by weight of phenolic resin), 10.5 parts by weight of imidazole, and 8.8 parts by weight of water. The composition of the obtained adhesive composition is shown in Table 1.

[0159] <Comparative Example 1-1>

[0160] [Preparation of adhesive composition]

[0161] Except that the given amounts of the above-mentioned alkaline phenolic resin aqueous solution and water were used in the manner shown in Table 1, the same procedure as in Examples 1-1 was followed to obtain the adhesive composition of Comparative Example 1-1. The composition of the obtained adhesive composition is shown in Table 1.

[0162] <Comparative Examples 1-2 and 1-3>

[0163] [Preparation of adhesive composition]

[0164] Except for the use of additives shown in Table 1 instead of imidazole, the same procedures as in Examples 1-1 were followed to obtain the adhesive compositions of Comparative Examples 1-2 and 1-3. The composition of the obtained adhesive compositions is shown in Table 1.

[0165] <Evaluation of Example 1-1 and Comparative Examples 1-1 to 1-3>

[0166] The adhesive compositions of Examples 1-1 and Comparative Examples 1-1 to 1-3 were evaluated as follows.

[0167] [Evaluation of viscosity increase rate]

[0168] For each adhesive composition, the viscosity at 25°C was measured using an E-type viscometer (manufactured by Tokyo Metrology & Instrument Co., Ltd.) immediately after manufacture and after being stored in a sealed container at 50°C for 30 days. The viscosity increase rate was calculated according to the following formula.

[0169] Viscosity increase rate (%) = (Viscosity after 30 days of storage at 50°C) / (Viscosity immediately after manufacturing) × 100

[0170] The smaller the viscosity increase rate mentioned above, the less thickening occurs, indicating better storage stability of the binder composition. The evaluation results are shown in Table 1.

[0171] [Liquidity Assessment]

[0172] 1000 parts by weight of refractory particles, 10 parts by weight of the aforementioned binder composition (stored at 50°C for 30 days), and 2.5 parts by weight of triacetin were added to a kitchen mixer "KENMIX AICOH CHEF" (manufactured by Aikosha Co., Ltd.) equipped with aluminum agitator blades. The mixture was stirred at 300 rpm for 2 minutes to obtain a molding composition. The resulting molding composition was filled from the top into a 50 mm Φ × 300 mm test cylinder until the top of the cylinder was reached, and the mixture was leveled. The weight was measured. It should be noted that silica sand ("Mikawa Silica Sand R-grade 6", manufactured by Mikawa Keiseki Co., Ltd.) was used as the refractory particles. The average particle size of the refractory particles was 181 μm. The evaluation results are shown in Table 1.

[0173] [Table 1]

[0174]

[0175] <Example 2-1>

[0176] [Preparation of adhesive composition]

[0177] The adhesive composition of Example 2-1 was obtained by using 80.7 parts by weight of the above-mentioned basic phenolic resin aqueous solution (47.3 parts by weight of basic phenolic resin), 1.5 parts by weight of sodium aluminate, 6.5 parts by weight of sodium tetraborate decahydrate (borax), 0.8 parts by weight of 3-epoxypropoxypropyltrimethoxysilane (KBM-403 manufactured by Shin-Etsu Chemical Industry Co., Ltd.) as a silane coupling agent, and 10.5 parts by weight of imidazole. The composition of the obtained adhesive composition is shown in Table 2.

[0178] <Examples 2-2 to 2-12 and Comparative Examples 2-1 to 2-6>

[0179] [Preparation of adhesive composition]

[0180] Except that given amounts of alkaline phenolic resin aqueous solution, sodium aluminate, sodium tetraborate decahydrate, and 3-epoxypropoxypropyltrimethoxysilane, and the compounds listed in Table 2 were used in the manner forming the compositions in Table 2, the same procedure as in Example 2-1 was followed to obtain the adhesive compositions of Examples 2-2 to 2-12 and Comparative Examples 2-1 to 2-6.

[0181] <Evaluation of Examples 2-1 to 2-12 and Comparative Examples 2-1 to 2-6>

[0182] The adhesive compositions of Examples 2-1 to 2-12 and Comparative Examples 2-1 to 2-6 were evaluated as follows.

[0183] [Evaluation of viscosity increase rate]

[0184] The viscosity of each adhesive composition at 25°C was measured using an E-type viscometer (manufactured by Tokyo Metrology Instruments Co., Ltd.) immediately after manufacture and after being stored in a sealed container at 50°C for 60 days. The viscosity increase rate was calculated according to the following formula.

[0185] Viscosity increase rate (%) = (Viscosity after 60 days of storage at 50°C) / (Viscosity immediately after manufacturing) × 100

[0186] The smaller the viscosity increase rate mentioned above, the less thickening occurs, indicating better storage stability of the binder composition. The evaluation results are shown in Table 2.

[0187] [Liquidity Assessment]

[0188] 1000 parts by weight of refractory particles and 30 parts by weight of the aforementioned binder composition, stored at 50°C for 60 days, were added to a kitchen mixer "KENMIX AICOH CHEF" (manufactured by Aikosha Co., Ltd.) equipped with aluminum agitator blades. The mixture was stirred at 300 rpm for 2 minutes to obtain a molding composition. The resulting molding composition was filled from the top into a 50 mm Φ × 300 mm test cylinder until the top of the cylinder was reached, and the mixture was leveled. The mass was measured. A higher mass value indicates better flowability. It should be noted that silica sand ("Mikawa Silica Sand R-grade 6," manufactured by Mikawa Keiseki Co., Ltd.) was used as the refractory particles. The average particle size of the refractory particles was 181 μm. The evaluation results are shown in Table 2.

[0189] [Evaluation of mold strength]

[0190] 1000 parts by weight of refractory particles and 30 parts by weight of the above-mentioned binder composition were added to a kitchen mixer "KENMIX AICOH CHEF" (manufactured by Aikosha Co., Ltd.) equipped with aluminum agitator blades, and mixed at 300 rpm for 2 minutes to obtain a molding composition. The obtained molding composition was filled into a 50 mm Φ × 50 mm wooden mold for test pieces, and carbon dioxide was passed through it at a flow rate of 20 L / min for 30 seconds at 25°C to obtain an evaluation test piece. After the test piece was left to stand at 25°C for 24 hours, it was evaluated using a compressive strength evaluation tester ("SDW 2000SH Special Type" Imada Co., Ltd.) at a speed of 5 mm / s to determine the molding compressive strength of the test piece. The evaluation results are shown in Table 2.

[0191] [Table 2]

[0192]

[0193] <Example 3-1 and Comparative Example 3-1>

[0194] [Preparation of adhesive composition]

[0195] The above-mentioned alkaline phenolic resin aqueous solution, sodium aluminate, 3-epoxypropoxypropyltrimethoxysilane, and imidazole were mixed to form the given amounts shown in Table 3, resulting in the adhesive compositions of Example 3-1 and Comparative Example 3-1. The adhesive compositions of Example 3-1 and Comparative Example 3-1 were evaluated as follows.

[0196] [Evaluation of viscosity increase rate]

[0197] The evaluation was conducted using the same method as in Example 1. The evaluation results are shown in Table 3.

[0198] [Liquidity Assessment]

[0199] The evaluation was conducted using the same method as in Example 1. The evaluation results are shown in Table 3.

[0200] [Table 3]

[0201]

Claims

1. A binder composition for casting molds, It contains alkaline phenolic resin, an imidazole compound as shown in formula (1) below, and water; The content of the imidazole compound in the adhesive composition for molding is 0.2 parts by weight or more and 60 parts by weight or less relative to 100 parts by weight of the alkaline phenolic resin. The water content in the adhesive composition used for molding is 10% by mass or more and 60% by mass or less. The imidazole compound contains R in the following general formula (1). 1 R 2 R 3 and R 4 Compounds with a total carbon number of 8 or less, In the general formula (1), R 1 R 2 R 3 and R 4 Each can be independently represented by a hydrogen group or a hydrocarbon group with 1 or more carbon atoms but less than 4 carbon atoms.

2. The adhesive composition for molding according to claim 1, wherein, The imidazole compound in the adhesive composition for molding is present in an amount of 0.1% by mass or more and 30% by mass or less.

3. The adhesive composition for molding according to claim 1 or 2, wherein, The content of the imidazole compound in the adhesive composition for molding is more than 1 part by mass and less than 35 parts by mass relative to 100 parts by mass of the alkaline phenolic resin.

4. The adhesive composition for molding according to claim 1 or 2, wherein, The content of the alkaline phenolic resin in the adhesive composition for casting is 10% by mass or more and 70% by mass or less.

5. The adhesive composition for molding according to claim 1 or 2, wherein, In the general formula (1), R 1 It indicates a hydrocarbon group with 1 or more carbon atoms and 4 or fewer carbon atoms.

6. The adhesive composition for molding according to claim 1 or 2, wherein, In the general formula (1), R 2 It indicates a hydrocarbon group with 1 or more carbon atoms and 4 or fewer carbon atoms.

7. The adhesive composition for molding according to claim 1 or 2, wherein, In the general formula (1), R 3 It indicates a hydrocarbon group with 1 or more carbon atoms and 4 or fewer carbon atoms.

8. The adhesive composition for molding according to claim 1 or 2, wherein, In the general formula (1), R 4 It indicates a hydrocarbon group with 1 or more carbon atoms and 4 or fewer carbon atoms.

9. The adhesive composition for molding according to claim 1 or 2, wherein, The imidazole compound contains R in the general formula (1). 1 R 2 R 3 and R 4 Compounds with a total carbon number of 6 or less.

10. The adhesive composition for molding according to claim 1 or 2, wherein, The imidazole compound comprises one or more selected from imidazole, 1-methylimidazolium, 1,2-dimethylimidazolium, 2-ethylimidazolium, 2-ethyl-4-methylimidazolium, and 1-isobutyl-2-methylimidazolium.

11. The adhesive composition for molding according to claim 1 or 2, wherein, The water content in the adhesive composition for molding the mold is 25% by mass or more and 40% by mass or less.

12. The mold-forming adhesive composition according to claim 1 or 2, wherein it contains an oxygen-containing anionic compound.

13. The adhesive composition for molding according to claim 12, wherein, The oxygen-containing anionic compound contains a boric acid compound.

14. The adhesive composition for molding according to claim 13, wherein, The boric acid compound in the oxygen-containing anionic compound has a content of 95% by mass or more.

15. The adhesive composition for molding according to claim 12, wherein, The content of the oxygen-containing anionic compound in the adhesive composition for casting mold is more than 1% by mass and less than 30% by mass.

16. The mold-forming adhesive composition according to claim 1 or 2, wherein it contains a silane coupling agent.

17. The adhesive composition for molding according to claim 16, wherein, The content of the silane coupling agent in the adhesive composition for molding is 0.1% to 5% by mass.

18. The mold-forming adhesive composition according to claim 1 or 2, wherein it contains aluminate.

19. The adhesive composition for molding according to claim 18, wherein, The content of the aluminate in the adhesive composition for molding the mold is more than 0.1% by mass and less than 10% by mass.

20. The adhesive composition for molding according to claim 1 or 2, wherein it is used for carbon dioxide curing.

21. A method for manufacturing a casting mold, comprising: In the mixing process, refractory particles and a binder composition for mold making are mixed to obtain a composition for mold making; and In the curing process, the molding composition is filled into the mold box, and the molding composition is then cured. The adhesive composition for molding the mold contains an alkaline phenolic resin, an imidazole compound as shown in formula (1) below, and water; The content of the imidazole compound in the adhesive composition for molding is 0.2 parts by weight or more and 60 parts by weight or less relative to 100 parts by weight of the alkaline phenolic resin. The water content in the adhesive composition used for molding is 10% by mass or more and 60% by mass or less. The imidazole compound contains R in the following general formula (1). 1 R 2 R 3 and R 4 Compounds with a total carbon number of 8 or less, In the general formula (1), R 1 R 2 R 3 and R 4 Each can be independently represented by a hydrogen group or a hydrocarbon group with 1 or more carbon atoms but less than 4 carbon atoms.

22. A method for manufacturing a casting mold, comprising: In the mixing process, refractory particles and a binder composition for mold making are mixed to obtain a composition for mold making; and In the curing process, the molding composition is filled into the mold box, and carbon dioxide is used to cure the molding composition. The adhesive composition for molding the mold contains an alkaline phenolic resin, an imidazole compound as shown in formula (1) below, and water. The content of the imidazole compound in the adhesive composition for molding is 0.2 parts by weight or more and 60 parts by weight or less relative to 100 parts by weight of the alkaline phenolic resin. The water content in the adhesive composition used for molding is 10% by mass or more and 60% by mass or less. The imidazole compound contains R in the following general formula (1). 1 R 2 R 3 and R 4 Compounds with a total carbon number of 8 or less, In the general formula (1), R 1 R 2 R 3 and R 4 Each can be independently represented by a hydrogen group or a hydrocarbon group with 1 or more carbon atoms but less than 4 carbon atoms.

23. A composition for molding a mold, comprising the binder composition for molding a mold as described in any one of claims 1 to 20 and refractory particles.

24. The composition for molding a casting mold according to claim 23, wherein, The content of the alkaline phenolic resin in the molding composition is 3 parts by mass or more and 80 parts by mass or less relative to 1000 parts by mass of the refractory particles.

25. The molding composition according to claim 23 or 24, wherein it is used for carbon dioxide curing.

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