Mold composition

Abstract

The present application is a mold composition containing refractory particles, a phenol resin, a curing agent, a compound represented by the following general formula (1), and a fatty acid having a carbon number of 8 or more and 22 or less. According to the present application, a mold composition having excellent fluidity while suppressing deterioration of workability at the time of use and at the time of storage of a mold building binder composition and a mold building curing agent composition can be provided. RO-(CH2CH2O)n-H (1) (in the general formula (1), R represents a linear or branched alkyl group or alkenyl group having a carbon number of 8 or more and 22 or less, and n represents the average addition mole number, and represents a number of 1.2 or more and 23 or less.)

Description

Technical Field

[0001] This invention relates to a molding composition. Background Technology

[0002] Various organic binders are used as binders in the manufacture of casting molds. Among them, alkali-phenolic resins are widely used, especially in the field of cast steel, as they can improve the quality of castings and the working environment.

[0003] However, when alkali-phenolic resin is mixed with recycled sand and then molded, the fluidity of the mold composition deteriorates significantly compared to virgin sand, making it unable to fill tightly. The aforementioned recycled sand specifically refers to recycled sand used as artificial sand, i.e., sand recycled for reuse after a single casting, or recycled sand that has been reused multiple times. Therefore, casting defects such as sand inclusions, sand adhesion, and penetrating sand adhesion occur in the resulting castings, leading to a reduction in casting quality.

[0004] Regarding the aforementioned issues, various solutions have been proposed to improve the fluidity of casting sand. For example, in the case of molding a mold by mixing self-curing water-soluble phenolic resin with a curing agent and using artificial sand as refractory particles, Japanese Patent Application Publication No. 10-216895 disclosed that surfactants and lubricants were included in the binder to improve the fluidity of the mold composition. Japanese Patent Application Publication No. 2009-40896 disclosed that nonionic surfactants were included in the curing agent for alkali phenolic resin to improve the fluidity of the mixed sand and reduce the generation of air bubbles in a one-liquid mold. Summary of the Invention

[0005] This invention is a molding composition.

[0006] It contains refractory particles, phenolic resin, curing agent, compound represented by the following general formula (1), and fatty acids with 8 or more carbon atoms and less than 22 carbon atoms.

[0007] RO-(CH2CH2O)nH (1)

[0008] (In the above general formula (1), R represents an alkyl or alkenyl group with 8 or more carbon atoms and 22 or less in the straight chain or branched chain, n represents the average number of addition moles, and n represents a number of 1.2 or more and 23 or less.)

[0009] In addition, the present invention is a curing agent composition for molding, which contains a curing agent, a compound represented by the following formula (1), and a fatty acid having 8 or more carbon atoms and 22 or fewer.

[0010] RO-(CH2CH2O)nH (1)

[0011] (In the above general formula (1), R represents an alkyl or alkenyl group with 8 or more carbon atoms and 22 or less in the straight chain or branched chain, n represents the average number of addition moles, and n represents a number of 1.2 or more and 23 or less.)

[0012] In addition, the present invention is a method for manufacturing a molding composition, the method comprising a step of mixing refractory particles, a molding binder composition containing phenolic resin, and the above-mentioned molding curing agent composition. Attached Figure Description

[0013] Figure 1 This is a cross-sectional view of a wooden mold used to evaluate the smoothness of the mold surface.

[0014] Figure 2 This is a photograph of the appearance of a mold manufactured for evaluating the smoothness of a surface, representing an embodiment.

[0015] Figure 3 This is a photograph of the appearance of a comparative mold manufactured for the purpose of evaluating surface smoothness.

[0016] Figure 4 It is a cross-sectional view of the mold, etc., used in the evaluation of casting quality.

[0017] Figure 5 It is a cross-sectional view of the mold, etc., used in the evaluation of casting quality.

[0018] Figure 6 It is a cross-sectional view of the mold, etc., used in the evaluation of casting quality.

[0019] Figure 7 It is a cross-sectional view of the mold, etc., used in the evaluation of casting quality.

[0020] Figure 8 This is a photograph of the appearance of a casting, which is an example of casting quality evaluation.

[0021] Figure 9 These are comparative examples of casting appearance photographs used in casting quality evaluation. Detailed Implementation

[0022] In Japanese Patent Application Publication No. 10-216895, when a surfactant is added to an adhesive (alkali-phenolic resin), bubbles are generated during preparation and use, making operation inconvenient. Furthermore, when a lubricant such as fatty acid is added to the adhesive, the fatty acid neutralizes and precipitates as agglomerates, making storage inconvenient. On the other hand, in Japanese Patent Application Publication No. 2009-40896, when a nonionic surfactant is added to a curing agent for alkali-phenolic resin, even with a certain amount of nonionic surfactant added, the flowability improvement effect reaches its peak, making it difficult to achieve a significant increase in flowability.

[0023] The present invention provides a mold composition and a method thereof that have excellent flowability while suppressing the deterioration of operability of the mold molding binder composition and the mold molding curing agent composition during use and storage.

[0024] This invention is a molding composition.

[0025] It contains refractory particles, phenolic resin, curing agent, compound represented by the following general formula (1), and fatty acids with 8 or more carbon atoms and less than 22 carbon atoms.

[0026] RO-(CH2CH2O)nH (1)

[0027] (In the above general formula (1), R represents an alkyl or alkenyl group with 8 or more carbon atoms and 22 or less in the straight chain or branched chain, n represents the average number of addition moles, and n represents a number of 1.2 or more and 23 or less.)

[0028] In addition, the present invention is a curing agent composition for molding, which contains a curing agent, a compound represented by the following formula (1), and a fatty acid having 8 or more carbon atoms and 22 or fewer.

[0029] RO-(CH2CH2O)nH (1)

[0030] (In the above general formula (1), R represents an alkyl or alkenyl group with 8 or more carbon atoms and 22 or less in the straight chain or branched chain, n represents the average number of addition moles, and n represents a number of 1.2 or more and 23 or less.)

[0031] In addition, the present invention is a method for manufacturing a molding composition, the method comprising a step of mixing refractory particles, a molding binder composition containing phenolic resin, and the above-mentioned molding curing agent composition.

[0032] According to the present invention, a mold composition and a method thereof can be provided that have excellent flowability while suppressing the deterioration of operability during use and storage of the mold molding adhesive composition and the mold molding curing agent composition.

[0033] Hereinafter, one embodiment of the present invention will be described.

[0034] <Molding Composition>

[0035] The molding composition of this embodiment contains refractory particles, phenolic resin, curing agent, compound represented by the following general formula (1), and fatty acid with 8 or more carbon atoms and 22 or less.

[0036] RO-(CH2CH2O)nH (1)

[0037] (In the above general formula (1), R represents an alkyl or alkenyl group with 8 or more carbon atoms and 22 or less in the straight chain or branched chain, n represents the average number of addition moles, and n represents a number of 1.2 or more and 23 or less.)

[0038] The molding composition of this embodiment exhibits excellent flowability. The reason for this effect is uncertain, but it can be considered as follows.

[0039] It can be assumed that if a nonionic surfactant is present in the casting composition containing phenolic resin, curing agent, and refractory particles, the surface tension of the mixture of phenolic resin and curing agent decreases, the sliding property between refractory particles increases, and the fluidity improves. On the other hand, it can be assumed that if fatty acids are present in the casting composition, they react with the alkali metals in the water-soluble phenolic resin to form fatty acid salts, which then precipitate out, exhibiting a bearing effect between the refractory particles, thus improving fluidity. In other words, the fluidity improvement effect obtained by containing nonionic surfactants differs in mechanism from that obtained by containing fatty acids. It can be assumed that by using additives with different mechanisms in combination, the fluidity improvement effect is significantly enhanced.

[0040] [Refractory particles]

[0041] As the aforementioned refractory particles, 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 can be used. Alternatively, recycled sand obtained by regenerating used refractory particles can also be used. It should be noted that refractory particles can be used alone or in combination with two or more types.

[0042] From the viewpoints of improving mold strength and economy, the average particle size of the aforementioned refractory particles is preferably 50 μm or more, more preferably 100 μm or more, and even more preferably 150 μm or more. From the viewpoint of improving mold strength, it is preferably 1000 μm or less, more preferably 800 μm or less, and even more preferably 600 μm or less. It should be noted that in this specification, the average particle size is determined using the method described in the examples.

[0043] [Phenolic resin]

[0044] The aforementioned phenolic resins are generally 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, other substituted phenols, cashew nut shell extract, etc. The aldehyde compounds can be one or a mixture of two or more, including formaldehyde, acetaldehyde, furfural, glyoxal, etc. These compounds can be used in aqueous solution as needed. Additionally, monomers capable of condensing with aldehyde compounds, such as urea, melamine, and cyclohexanone, 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, can also be mixed in.

[0045] Examples of alkaline catalysts used in the synthesis of the aforementioned phenolic resins include alkali metal hydroxides such as LiOH, NaOH, and KOH, with NaOH and KOH being particularly preferred. Alternatively, these alkaline catalysts can be used in combination.

[0046] The aforementioned phenolic resin is preferably prepared as an aqueous solution. From the viewpoint of improving mold strength, the solid content (solid content after drying at 105°C for 3 hours) is preferably 30% by mass or more, and more preferably 50% by mass or more. From the viewpoints of improving mold strength and workability, the solid content of the aforementioned phenolic resin aqueous solution is preferably 85% by mass or less, and more preferably 75% by mass or less. Furthermore, from the viewpoints of improving mold strength and workability, the solid content of the aforementioned phenolic resin aqueous solution is preferably 30-80% by mass, and more preferably 50-75% by mass.

[0047] From the viewpoint of improving mold strength, the weight-average molecular weight (Mw) of the phenolic resin is preferably 500 or more, more preferably 800 or more, and even more preferably 1200 or more. From the viewpoints of improving mold strength and workability, the weight-average molecular weight (Mw) of the phenolic resin is preferably 8000 or less, more preferably 5000 or less, and even more preferably 3000 or less. Furthermore, from the viewpoints of improving mold strength and workability, the weight-average molecular weight (Mw) of the phenolic resin is preferably 500 to 8000, more preferably 800 to 5000, and even more preferably 1200 to 3000. It should be noted that the weight-average molecular weight of the phenolic resin was determined using the method described in the examples.

[0048] From the viewpoint of improving mold strength, the content of the phenolic resin in the mold composition relative to 100 parts by mass of the refractory particles is preferably 0.1 parts by mass or more, more preferably 0.2 parts by mass or more, and even more preferably 0.3 parts by mass or more. From the viewpoints of improving workability and economy, the content of the phenolic resin in the mold composition relative to 100 parts by mass of the refractory particles is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and even more preferably 1 part by mass or less. Furthermore, from the viewpoints of improving mold strength, improving workability, and economy, the content of the phenolic resin in the mold composition relative to 100 parts by mass of the refractory particles is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 3 parts by mass, and even more preferably 0.3 to 1 part by mass.

[0049] [The compound represented by the above general formula (1)]

[0050] The compounds represented by the above general formula (1) include compounds in which R in the above general formula (1) represents an alkyl or alkenyl group with 8 or more and 22 or less carbon atoms in a straight chain or branched chain, preferably compounds in which alkyl or alkenyl groups with 8 or more and 22 or less carbon atoms in a straight chain are included.

[0051] From the viewpoints of improving the flowability of the molding composition and the availability of raw materials, the compound represented by the above general formula (1) comprises a compound in which the alkyl or alkenyl group represented by R in the above general formula (1) has 8 or more carbon atoms, preferably 10 or more, and more preferably 12 or more. From the viewpoints of improving the flowability of the molding composition, the viewpoints of storage stability, and the viewpoints of the availability of raw materials, the compound represented by the above general formula (1) comprises a compound in which the alkyl or alkenyl group represented by R in the above general formula (1) has 22 or fewer carbon atoms, preferably 20 or fewer, and more preferably 18 or fewer. From the viewpoints of improving the flowability of the molding composition, the viewpoints of storage stability, and the viewpoints of the availability of raw materials, the compound represented by the above general formula (1) comprises a compound in which the alkyl or alkenyl group represented by R in the above general formula (1) has 8 to 22 carbon atoms, preferably 10 to 20, and more preferably 12 to 18.

[0052] From the viewpoints of improving the flowability of the molding composition and the availability of raw materials, the compound represented by the above general formula (1) includes a compound in which n in the above general formula (1) is 1.2 or more, preferably 1.5 or more, and more preferably 1.8 or more. From the viewpoints of improving the flowability of the molding composition, the viewpoints of storage stability, and the viewpoints of the availability of raw materials, the compound represented by the above general formula (1) includes a compound in which n in the above general formula (1) is 23 or less, preferably 18 or less, and more preferably 13 or less. In addition, from the viewpoints of improving the flowability of the molding composition, the viewpoints of storage stability, and the viewpoints of the availability of raw materials, the compound represented by the above general formula (1) includes a compound in which n in the above general formula (1) is 1.2 to 23, preferably 1.5 to 18, and more preferably 1.8 to 13.

[0053] From the viewpoint of improving the fluidity of the molding composition, the content of the compound represented by the above-mentioned general formula (1) in the molding composition relative to 100 parts by mass of the refractory particles is preferably 0.001 parts by mass or more, more preferably 0.003 parts by mass or more, and even more preferably 0.005 parts by mass or more. From the viewpoints of improving the fluidity, anti-foaming properties, storage stability, and economy of the molding composition, the content of the compound represented by the above-mentioned general formula (1) in the molding composition relative to 100 parts by mass of the refractory particles is preferably 0.1 parts by mass or less, more preferably 0.05 parts by mass or less, and even more preferably 0.02 parts by mass or less. Furthermore, from the viewpoints of improving the fluidity, anti-foaming properties, storage stability, and economy of the molding composition, the content of the compound represented by the above-mentioned general formula (1) in the molding composition relative to 100 parts by mass of the refractory particles is preferably 0.001 to 0.1 parts by mass, more preferably 0.003 to 0.05 parts by mass, and even more preferably 0.005 to 0.02 parts by mass.

[0054] From the viewpoint of improving the fluidity of the molding composition, the content of the compound represented by the above general formula (1) in the molding composition relative to 100 parts by mass of the phenolic resin and the curing agent is preferably 0.5 parts by mass or more, more preferably 0.75 parts by mass or more, even more preferably 1 part by mass or more, even more preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more. From the viewpoints of improving the fluidity, foam suppression, storage stability, and economy of the molding composition, the content of the compound represented by the above general formula (1) in the molding composition relative to 100 parts by mass of the phenolic resin and the curing agent is preferably 15 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 5 parts by mass or less. Furthermore, from the viewpoints of improving the fluidity of the molding composition, the viewpoint of suppressing foaming, the viewpoint of preservation stability, and the viewpoint of economy, the content of the compound represented by the above general formula (1) in the above molding composition relative to a total of 100 parts by mass of the above phenolic resin and the above curing agent is preferably 0.5 to 15 parts by mass, more preferably 0.75 to 15 parts by mass, even more preferably 1 to 15 parts by mass, even more preferably 1 to 10 parts by mass, and even more preferably 1 to 5 parts by mass.

[0055] 〔fatty acid〕

[0056] From the viewpoints of improving the flowability of the molding composition and the availability of raw materials, the aforementioned fatty acid comprises fatty acids having 8 or more carbon atoms, preferably 10 or more, and more preferably 12 or more. From the viewpoints of storage stability, improving the flowability of the molding composition, and the availability of raw materials, the aforementioned fatty acid comprises fatty acids having 22 or fewer carbon atoms, preferably 20 or fewer, and more preferably 18 or fewer. Furthermore, from the viewpoints of storage stability, improving the flowability of the molding composition, and the availability of raw materials, the aforementioned fatty acid comprises fatty acids having 8 to 22 carbon atoms, preferably 10 to 20, and more preferably 12 to 18.

[0057] From the viewpoint of preserving stability and improving the flowability of the molding composition, the fatty acids mentioned above preferably include fatty acids with a melting point below 45°C.

[0058] Examples of the aforementioned fatty acids include straight-chain aliphatic carboxylic acids, branched-chain aliphatic carboxylic acids, saturated fatty acid carboxylic acids, and unsaturated aliphatic carboxylic acids. Specifically, examples include lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, heptadecanoic acid, stearic acid, nonadecanoic acid, oleic acid, linoleic acid, and linolenic acid. From the viewpoint of improving the flowability of the molding composition and the availability of raw materials, the aforementioned fatty acids preferably include one or more selected from oleic acid, linolenic acid, and lauric acid.

[0059] From the viewpoint of improving the fluidity of the molding composition, the content of the fatty acid in the molding composition relative to 100 parts by mass of the refractory particles is preferably 0.0005 parts by mass or more, more preferably 0.00075 parts by mass or more, and even more preferably 0.001 parts by mass or more. From the viewpoints of improving the fluidity, anti-foaming properties, storage stability, and economy of the molding composition, the content of the fatty acid in the molding composition relative to 100 parts by mass of the refractory particles is preferably 0.05 parts by mass or less, more preferably 0.02 parts by mass or less, and even more preferably 0.01 parts by mass or less. Furthermore, from the viewpoints of improving the fluidity, anti-foaming properties, storage stability, and economy of the molding composition, the content of the fatty acid in the molding composition relative to 100 parts by mass of the refractory particles is preferably 0.0005 to 0.05 parts by mass, more preferably 0.00075 to 0.02 parts by mass, and even more preferably 0.001 to 0.01 parts by mass.

[0060] From the viewpoint of improving the flowability of the molding composition, the content of the fatty acid in the molding composition relative to 100 parts by mass of the phenolic resin and the curing agent is preferably 0.05 parts by mass or more, more preferably 0.075 parts by mass or more, even more preferably 0.1 parts by mass or more, even more preferably 0.25 parts by mass or more, and even more preferably 0.4 parts by mass or more. From the viewpoints of improving the flowability, anti-foaming properties, storage stability, and economy of the molding composition, the content of the fatty acid in the molding composition relative to 100 parts by mass of the phenolic resin and the curing agent is preferably 7 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 3 parts by mass or less. Furthermore, from the viewpoints of improving the fluidity of the molding composition, suppressing foaming, maintaining storage stability, and being economical, the content of the fatty acid in the molding composition relative to 100 parts by mass of the phenolic resin and the curing agent is preferably 0.05 to 7 parts by mass, more preferably 0.075 to 7 parts by mass, even more preferably 0.1 to 7 parts by mass, even more preferably 0.1 to 5 parts by mass, and even more preferably 0.1 to 3 parts by mass.

[0061] From the viewpoint of improving the fluidity of the molding composition, the ratio of the content of the fatty acids in the molding composition relative to the total content of the compound represented by the general formula (1) and the fatty acids (content of the fatty acids / (total content of the compound represented by the general formula (1) and the fatty acids)) is preferably 0.05 or more, more preferably 0.08 or more, and even more preferably 0.1 or more. From the viewpoints of improving the fluidity, anti-foaming properties, storage stability, and economy of the molding composition, the ratio of the content of the fatty acids in the molding composition relative to the total content of the compound represented by the general formula (1) and the fatty acids is preferably 0.6 or less, more preferably 0.5 or less, and even more preferably 0.4 or less. From the viewpoints of improving the fluidity, anti-foaming properties, storage stability, and economy of the molding composition, the ratio of the content of the fatty acids in the molding composition relative to the total content of the compound represented by the general formula (1) and the fatty acids is preferably 0.05 to 0.6, more preferably 0.08 to 0.5, and even more preferably 0.1 to 0.4.

[0062] From the viewpoint of improving the fluidity of the molding composition, the mass ratio of the compound represented by the above general formula (1) to the above fatty acid in the molding composition (mass of the compound represented by the above general formula (1) / mass of the above fatty acid) is preferably 0.15 or more, more preferably 0.5 or more, and even more preferably 0.9 or more. From the viewpoints of improving the fluidity, anti-foaming properties, storage stability, and economy of the molding composition, the mass ratio of the compound represented by the above general formula (1) to the above fatty acid in the molding composition is preferably 100 or less, more preferably 20 or less, and even more preferably 10 or less. From the viewpoints of improving the fluidity, anti-foaming properties, storage stability, and economy of the molding composition, the mass ratio of the compound represented by the above general formula (1) to the above fatty acid in the molding composition is preferably 0.15 to 100, more preferably 0.5 to 20, and even more preferably 0.9 to 10.

[0063] [Curing agent]

[0064] The curing agent described above can be used without particular limitation as long as it cures the phenolic resin; however, from the viewpoint of improving mold strength, ester compounds are preferred. Examples of such ester compounds include lactones, organic ester compounds derived from mono- or polyols having 1 to 10 carbon atoms and organic carboxylic acids having 1 to 10 carbon atoms, carbonates, and mixtures thereof. Specifically, examples of lactones include γ-butyrolactone, propiolactone, and ε-caprolactone. Examples of organic ester compounds include ethyl formate, ethylene glycol diacetate, ethylene glycol monoacetate, triethylene glycol diacetate, triethylene glycol monoacetate, ethyl acetoacetate, dimethyl succinate, dimethyl glutarate, dimethyl adipate, triacetin, dimethyl 2-ethylsuccinate, dimethyl 2-methylglutarate, and dimethyl 2-methyladipate. Examples of carbonates include ethylene carbonate and propylene carbonate. Among these, from the viewpoints of ease of controlling mold strength, availability, and economy, one or more of the following are preferred: γ-butyrolactone, propiolactone, ε-caprolactone, ethyl formate, ethylene glycol diacetate, ethylene glycol monoacetate, triacetin, propylene carbonate, dimethyl glutarate, dimethyl adipate, triethylene glycol diacetate, dimethyl succinate, dimethyl 2-ethylsuccinate, dimethyl 2-methylglutarate, and dimethyl 2-methyladipate. Furthermore, methyl formate is preferred in gas-curing mold molding methods using ester compounds.

[0065] From the viewpoints of improving mold strength and increasing curing speed, the content of the curing agent in the above-mentioned mold composition relative to 100 parts by weight of the above-mentioned phenolic resin is preferably 10 parts by weight or more, more preferably 15 parts by weight or more, further preferably 20 parts by weight or more, and even more preferably 25 parts by weight or more. From the viewpoints of improving mold strength, increasing curing speed, and economy, the content of the curing agent in the above-mentioned mold composition relative to 100 parts by weight of the above-mentioned phenolic resin is preferably 70 parts by weight or less, more preferably 60 parts by weight or less, further preferably 50 parts by weight or less, and even more preferably 45 parts by weight or less. From the viewpoints of improving mold strength, increasing curing speed, and economy, the content of the curing agent in the above-mentioned mold composition relative to 100 parts by weight of the above-mentioned phenolic resin is preferably 10 to 70 parts by weight, more preferably 15 to 60 parts by weight, further preferably 20 to 50 parts by weight, and even more preferably 25 to 45 parts by weight.

[0066] [Other ingredients]

[0067] From the viewpoint of improving the working environment, the above-mentioned mold composition preferably contains resorcinol. Resorcinol has the function of capturing formaldehyde, thus reducing the formaldehyde contained in the thermal decomposition gases during, after, and during demolding.

[0068] From the viewpoints of reducing formaldehyde and improving mold strength, the resorcinol content in the above-mentioned mold composition is preferably 0.001% by mass or more, more preferably 0.003% by mass or more, and even more preferably 0.005% by mass or more. From the viewpoints of reducing formaldehyde, improving mold strength, and economy, the resorcinol content in the above-mentioned mold composition is preferably 0.06% by mass or less, more preferably 0.04% by mass or less, and even more preferably 0.02% by mass or less. Furthermore, from the viewpoints of reducing formaldehyde, improving mold strength, and economy, the resorcinol content in the above-mentioned mold composition is preferably 0.001 to 0.06% by mass, more preferably 0.003 to 0.04% by mass, and even more preferably 0.005 to 0.02% by mass.

[0069] The above-described molding composition may include other components without impairing the effects of the present invention. Examples of other components include solvents such as water, alcohols, ether alcohols, and glycols. Among these, from the viewpoint of the feel of the mixed sand and the viewpoint of suppressing odor, it is preferable to select one or more of water, alcohols, ether alcohols, and glycols; more preferably, it is preferable to select one or more of water, alcohols having 1 to 3 carbon atoms, diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol, and benzyl alcohol; even more preferably, it is preferable to select one or more of methanol, ethanol, diethylene glycol, and triethylene glycol; and even more preferably, it is preferable to select water and triethylene glycol.

[0070] From the viewpoint of uniformly mixing the raw materials, the content of the solvent in the above-mentioned molding composition is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, and even more preferably 0.03% by mass or more. From the viewpoint of uniformly mixing the raw materials, suppressing odor, and economy, the content of the solvent in the above-mentioned molding composition is preferably 0.9% by mass or less, more preferably 0.8% by mass or less, and even more preferably 0.7% by mass or less. From the viewpoint of uniformly mixing the raw materials, suppressing odor, and economy, the content of the solvent in the above-mentioned molding composition is preferably 0.01 to 0.9% by mass, more preferably 0.02 to 0.8% by mass, and even more preferably 0.03 to 0.7% by mass.

[0071] <Curing agent composition for molding>

[0072] The mold-forming curing agent composition of this embodiment (hereinafter sometimes simply referred to as the curing agent composition) comprises the above-described curing agent, the compound shown in the above-described general formula (1), and the above-described fatty acid. If the compound shown in the above-described general formula (1) and the fatty acid having 8 or more but less than 22 carbon atoms are added to the mold-forming binder composition, bubbles or agglomerates will be generated. However, if the curing agent composition contains the compound shown in the above-described general formula (1) and the fatty acid having 8 or more but less than 22 carbon atoms, the fluidity of the mold composition can be improved while suppressing bubbles and agglomerates.

[0073] From the viewpoint of improving the fluidity of the mold composition, the content of the compound represented by the above general formula (1) in the curing agent composition is preferably 1% by mass or more, more preferably 1.5% by mass or more, and even more preferably 2% by mass or more. From the viewpoint of improving the fluidity of the mold composition, the viewpoint of storage stability, the viewpoint of low-temperature stability, and the viewpoint of economy, the content of the compound represented by the above general formula (1) in the curing agent composition is preferably 10% by mass or less, more preferably 7% by mass or less, and even more preferably 5% by mass or less. Furthermore, from the viewpoint of improving the fluidity of the mold composition, the viewpoint of storage stability, the viewpoint of low-temperature stability, and the viewpoint of economy, the content of the compound represented by the above general formula (1) in the curing agent composition is preferably 1 to 10% by mass, more preferably 1.5 to 7% by mass, and even more preferably 2 to 5% by mass.

[0074] From the viewpoint of improving the fluidity of the molding composition, the content of the fatty acid in the curing agent composition is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and even more preferably 0.3% by mass or more. From the viewpoint of improving the fluidity of the molding composition, the viewpoint of storage stability, the viewpoint of low-temperature stability, and the viewpoint of economy, the content of the fatty acid in the curing agent composition is preferably 6% by mass or less, more preferably 5% by mass or less, even more preferably 4% by mass or less, and even more preferably 3% by mass or less. In addition, from the viewpoint of improving the fluidity of the molding composition, the viewpoint of storage stability, the viewpoint of low-temperature stability, and the viewpoint of economy, the content of the compound represented by the above general formula (1) in the curing agent composition is preferably 0.1 to 6% by mass, more preferably 0.2 to 5% by mass, even more preferably 0.3 to 4% by mass, and even more preferably 0.3 to 3% by mass.

[0075] From the viewpoint of improving mold strength, the content of the curing agent in the above-mentioned curing agent composition is preferably 60% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, and even more preferably 85% by mass or more. From the viewpoint of improving mold strength and economy, the content of the curing agent in the above-mentioned curing agent composition is preferably 99% by mass or less, more preferably 98% by mass or less, and even more preferably 97% by mass or less. Furthermore, from the viewpoint of improving mold strength and economy, the content of the curing agent in the above-mentioned curing agent composition is preferably 60 to 99% by mass, more preferably 70 to 98% by mass, further preferably 80 to 97% by mass, and even more preferably 85 to 97% by mass.

[0076] From the viewpoint of improving the fluidity of the molding composition, the ratio of the content of the fatty acid in the curing agent composition relative to the total content of the compound represented by the general formula (1) and the fatty acid (content of the fatty acid / (total content of the compound represented by the general formula (1) and the fatty acid)) is preferably 0.05 or more, more preferably 0.08 or more, and even more preferably 0.1 or more. From the viewpoints of improving the fluidity, anti-foaming properties, storage stability, and economy of the molding composition, the ratio of the content of the fatty acid in the curing agent composition relative to the total content of the compound represented by the general formula (1) and the fatty acid is preferably 0.6 or less, more preferably 0.5 or less, and even more preferably 0.4 or less. From the viewpoints of improving the fluidity, anti-foaming properties, storage stability, and economy of the molding composition, the ratio of the content of the fatty acid in the curing agent composition relative to the total content of the compound represented by the general formula (1) and the fatty acid is preferably 0.05 to 0.6, more preferably 0.08 to 0.5, and even more preferably 0.1 to 0.4.

[0077] [Other ingredients]

[0078] From the viewpoint of improving the working environment, the above-mentioned curing agent composition preferably contains resorcinol.

[0079] From the viewpoints of reducing formaldehyde and improving mold strength, the resorcinol content in the above-mentioned curing agent composition is preferably 1% by mass or more, more preferably 1.5% by mass or more, and even more preferably 2% by mass or more. From the viewpoints of reducing formaldehyde, improving mold strength, and economy, the resorcinol content in the above-mentioned curing agent composition is preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less, and even more preferably 5% by mass or less. Furthermore, from the viewpoints of reducing formaldehyde, improving mold strength, and economy, the resorcinol content in the above-mentioned curing agent composition is preferably 1 to 20% by mass, more preferably 1.5 to 15% by mass, even more preferably 2 to 10% by mass, and even more preferably 2 to 5% by mass.

[0080] The curing agent composition described above may include other components without impairing the effects of the present invention. Examples of other components include solvents such as water, alcohols, ether alcohols, and glycols. From the viewpoints of compatibility between the curing agent and the aforementioned phenolic resin, the tactile feel of the molding composition, and odor suppression, it is preferable to select one or more from alcohols, ether alcohols, and glycols; more preferably, one or more from alcohols having 1 to 3 carbon atoms, diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol, and benzyl alcohol; even more preferably, one or more from methanol, ethanol, diethylene glycol, triethylene glycol, and benzyl alcohol; and even more preferably, triethylene glycol.

[0081] From the viewpoint of uniformly mixing the raw materials, the content of the solvent in the above-mentioned curing agent composition is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 3% by mass or more. From the viewpoint of uniformly mixing the raw materials, suppressing odor, and economic efficiency, the content of the solvent in the above-mentioned curing agent composition is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less. From the viewpoint of uniformly mixing the raw materials, suppressing odor, and economic efficiency, the content of the solvent in the above-mentioned curing agent composition is preferably 1 to 30% by mass, more preferably 2 to 25% by mass, and even more preferably 3 to 20% by mass.

[0082] <Method for manufacturing the mold composition>

[0083] The above-described molding composition can be manufactured using known methods. An example of a method for manufacturing the above-described molding composition is a mixing step that includes mixing the above-described refractory particles, a molding binder composition containing the above-described phenolic resin, and the above-described curing agent composition.

[0084] [Binder composition for casting]

[0085] From the viewpoint of improving mold strength, the content of the water-soluble phenolic resin in the above-mentioned mold-forming adhesive composition (hereinafter sometimes simply referred to as the adhesive composition) is preferably 10% by mass or more, more preferably 20% by mass or more, further preferably 30% by mass or more, and even more preferably 40% by mass or more. From the viewpoint of improving mold strength and workability, the content of the water-soluble phenolic resin in the above-mentioned adhesive composition is preferably 95% by mass or less, more preferably 80% by mass or less, further preferably 70% by mass or less, and even more preferably 60% by mass or less. Furthermore, from the viewpoint of improving mold strength and workability, the content of the water-soluble phenolic resin in the above-mentioned adhesive composition is preferably 10 to 95% by mass, more preferably 20 to 80% by mass, further preferably 30 to 70% by mass, and even more preferably 40 to 60% by mass.

[0086] [Other ingredients]

[0087] The above-described binder composition may further contain additives such as water, silane coupling agents, urea, surfactants, and alcohols to a degree that does not impair the effects of this embodiment. It should be noted that the presence of a silane coupling agent in the above-described binder composition can further improve the final strength of the resulting mold, and is therefore preferred. Examples of the above-described silane coupling agents include γ-(2-amino)propylmethyldimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-epoxypropoxypropyltrimethoxysilane, and N-β-(aminoethyl)γ-aminopropylmethyldimethoxysilane. From the viewpoint of improving mold strength, the content of the above-described silane coupling agent in the above-described binder composition is preferably 0.1 to 5% by mass, more preferably 0.3 to 1% by mass.

[0088] 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.

[0089] <Mold Manufacturing Method>

[0090] 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 having a curing step that fills the mold composition into the mold and cures the mold composition can be cited.

[0091] Regarding the above-described embodiments, the present invention further discloses the following embodiments.

[0092] <1>

[0093] A molding composition comprising refractory particles, phenolic resin, curing agent, a compound represented by the following general formula (1), and a fatty acid having 8 or more carbon atoms and 22 or fewer carbon atoms.

[0094] RO-(CH2CH2O)nH (1)

[0095] (In the above general formula (1), R represents an alkyl or alkenyl group with 8 or more carbon atoms and 22 or less in the straight chain or branched chain, n represents the average number of addition moles, and n represents a number of 1.2 or more and 23 or less.)

[0096] <2>

[0097] According to the molding composition described in <1>, the content of the phenolic resin is 0.1 parts by mass or more and 5 parts by mass or less relative to 100 parts by mass of the refractory particles.

[0098] <3>

[0099] According to the molding composition described in <1> or <2>, the content of the phenolic resin is 0.3 parts by mass or more and 1 part by mass or less relative to 100 parts by mass of the refractory particles.

[0100] <4>

[0101] According to any one of <1> to <3>, the content of the curing agent is 10 parts by mass or more and 70 parts by mass or less relative to 100 parts by mass of the phenolic resin.

[0102] <5>

[0103] According to any one of <1> to <4>, the content of the curing agent is 25 parts by mass or more and 45 parts by mass or less relative to 100 parts by mass of the phenolic resin.

[0104] <6>

[0105] According to any one of <1> to <5>, the molding composition wherein the curing agent comprises at least one selected from γ-butyrolactone, propiolactone, ε-caprolactone, ethyl formate, ethylene glycol diacetate, ethylene glycol monoacetate, triacetin, propylene carbonate, dimethyl glutarate, dimethyl adipate, dimethyl succinate, triethylene glycol diacetate, dimethyl 2-ethylsuccinate, dimethyl 2-methylglutarate, and dimethyl 2-methyladipate.

[0106] <7>

[0107] According to any one of <1> to <6>, the content of the compound represented by the above general formula (1) is more than 0.001 parts by mass and less than 0.1 parts by mass relative to 100 parts by mass of the above refractory particles.

[0108] <8>

[0109] According to any one of <1> to <7>, the content of the compound represented by the above general formula (1) is 0.005 parts by mass or more and 0.02 parts by mass or less relative to 100 parts by mass of the above refractory particles.

[0110] <9>

[0111] According to any one of <1> to <8>, the content of the compound represented by the above general formula (1) is 1% by mass or more and 10% by mass or less, relative to a total of 100 parts by mass of the above phenolic resin and the above curing agent.

[0112] <10>

[0113] According to any one of <1> to <9>, the content of the compound represented by the above general formula (1) is 1% by mass or more and 5% by mass or less, relative to a total of 100 parts by mass of the above phenolic resin and the above curing agent.

[0114] <11>

[0115] According to any one of <1> to <10>, the molding composition wherein the compound represented by the above general formula (1) comprises a compound in the above general formula (1) where R represents an alkyl or alkenyl group with a straight chain of 10 or more and 20 or less carbon atoms, and n represents a number of 1.8 or more and 13 or less.

[0116] <12>

[0117] According to any one of <1> to <11>, the content of the fatty acid is 0.001 parts by mass or more and 0.01 parts by mass or less relative to 100 parts by mass of the refractory particles.

[0118] <13>

[0119] According to any one of <1> to <12>, the content of the fatty acid is 0.25 parts by mass or more and 5 parts by mass or less relative to a total of 100 parts by mass of the phenolic resin and the curing agent.

[0120] <14>

[0121] According to any one of <1> to <13>, the content of the fatty acid is 0.4 parts by mass or more and 3 parts by mass or less relative to a total of 100 parts by mass of the phenolic resin and the curing agent.

[0122] <15>

[0123] According to any one of <1> to <14>, the molding composition wherein the fatty acid comprises a fatty acid with a melting point of 45°C or less.

[0124] <16>

[0125] According to any one of <1> to <15>, the molding composition wherein the fatty acid comprises one or more selected from oleic acid, linolenic acid and lauric acid.

[0126] <17>

[0127] According to any one of <1> to <16>, the content of the fatty acid is 0.05 or more and 0.6 or less relative to the total content of the compound shown in the above general formula (1) and the fatty acid.

[0128] <18>

[0129] According to any one of <1> to <17>, the content of the fatty acid is 0.1 or more and 0.4 or less relative to the total content of the compound shown in the above general formula (1) and the fatty acid.

[0130] <19>

[0131] A curing agent composition for molding, comprising a curing agent, a compound of the following general formula (1), and a fatty acid having 8 or more carbon atoms and 22 or fewer carbon atoms.

[0132] RO-(CH2CH2O)nH (1)

[0133] (In the above general formula (1), R represents an alkyl or alkenyl group with 8 or more carbon atoms and 22 or less in the straight chain or branched chain, n represents the average number of addition moles, and n represents a number of 1.2 or more and 23 or less.)

[0134] <20>

[0135] According to the curing agent composition for molding of molds described in <19>, the content of the curing agent in the curing agent composition is 80% by mass or more and 97% by mass or less.

[0136] <21>

[0137] According to the curing agent composition for molding as described in <19> or <20>, the content of the curing agent in the curing agent composition is 85% by mass or more and 97% by mass or less.

[0138] <22>

[0139] According to any one of <19> to <21>, the curing agent composition for molding is provided, wherein the curing agent comprises at least one selected from γ-butyrolactone, propiolactone, ε-caprolactone, ethyl formate, ethylene glycol diacetate, ethylene glycol monoacetate, triacetin, propylene carbonate, dimethyl glutarate, dimethyl adipate, dimethyl succinate, triethylene glycol diacetate, dimethyl 2-ethylsuccinate, dimethyl 2-methylglutarate, and dimethyl 2-methyladipate.

[0140] <23>

[0141] According to any one of <19> to <22>, the content of the compound represented by the above general formula (1) is 1% by mass or more and 10% by mass or less.

[0142] <24>

[0143] According to any one of <19> to <23>, the content of the compound represented by the above general formula (1) is 2% by mass or more and 5% by mass or less.

[0144] <25>

[0145] According to any one of <19> to <24>, the curing agent composition for molding is wherein the compound represented by the above general formula (1) comprises a compound in the above general formula (1) where R represents an alkyl or alkenyl group with a straight chain of 10 or more and 20 or less carbon atoms, and n represents a number of 1.8 or more and 13 or less.

[0146] <26>

[0147] According to any one of <19> to <25>, the curing agent composition for molding is wherein the content of the aforementioned fatty acid is 0.1% by mass or more and 6% by mass or less.

[0148] <27>

[0149] According to any one of <19> to <26>, the curing agent composition for molding is wherein the content of the aforementioned fatty acid is 0.3% by mass or more and 3% by mass or less.

[0150] <28>

[0151] According to any one of <19> to <27>, the curing agent composition for molding is wherein the fatty acid comprises a fatty acid with a melting point of 45°C or less.

[0152] <29>

[0153] According to any one of <19> to <28>, the curing agent composition for molding is wherein the fatty acid comprises one or more selected from oleic acid, linolenic acid and lauric acid.

[0154] <30>

[0155] According to any one of <19> to <29>, the curing agent composition for molding is wherein the content of the fatty acid is 0.05 or more and 0.6 or less relative to the total content of the compound shown in the above general formula (1) and the fatty acid.

[0156] <31>

[0157] According to any one of <19> to <30>, the curing agent composition for molding is wherein the content of the fatty acid is 0.1 or more and 0.4 or less relative to the total content of the compound shown in the above general formula (1) and the fatty acid.

[0158] <32>

[0159] The curing agent composition for molding according to any one of <19> to <31> further contains resorcinol, wherein the content of resorcinol is 2% by mass or more and 10% by mass or less.

[0160] <33>

[0161] The curing agent composition for molding according to any one of <19> to <32> further contains resorcinol, wherein the content of resorcinol is 2% by mass or more and 5% by mass or less.

[0162] <34>

[0163] A method for manufacturing a molding composition includes a step of mixing refractory particles, a molding binder composition containing phenolic resin, and a molding curing agent composition as described in any one of <19> to <33>.

[0164] Example

[0165] Hereinafter, specific embodiments of the present invention will be described.

[0166] <Methods for evaluating raw materials>

[0167] [Weight-average molecular weight (Mw) of phenolic resin]

[0168] (a) Sample preparation: Add the same weight of ion-exchanged water to the sample, and neutralize with 0.1% by weight of H2SO4. Filter the resulting precipitate, wash with water, and dry. Dissolve it in tetrahydrofuran (THF) to prepare the sample for GPC.

[0169] (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 them in the order of guard column - 3000HXL - 2500HXL from the injection port side.

[0170] (c) Standard material: Polystyrene (manufactured by Toyo Soda Industries, Ltd.)

[0171] (d) Eluent: THF (flow rate: 1 cm) 3 / min)

[0172] (e) Column temperature: 25℃

[0173] (f) Detector: Ultraviolet spectrophotometer (for quantification at the wavelength of the maximum ultraviolet absorption peak of phenol)

[0174] (g) Segmentation method for calculating molecular weight: time segmentation (2 sec)

[0175] <Method for determining the average particle size of refractory particles>

[0176] 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.

[0177] <Raw Material Manufacturing>

[0178] [Preparation of the adhesive composition]

[0179] To an aqueous solution obtained by mixing 10 mol of phenol, 50% potassium hydroxide aqueous solution (0.40 mol / L relative to phenol), and 50% sodium hydroxide aqueous solution (0.40 mol / L relative to phenol), water was further added, followed by the addition of 92% paraformaldehyde (2.00 mol / L relative to phenol). A polycondensation reaction was carried out at 80°C until the weight-average molecular weight of the phenolic resin reached 2000. Then, 0.5 parts by weight of γ-epoxypropoxypropyltrimethoxysilane were added per 100 parts by weight of the reaction solution to obtain a binder composition containing phenolic resin (weight-average molecular weight 2000) (solid content 49.1–50% by weight).

[0180] [Manufacturing of Refractory Particles]

[0181] [Manufacturing of Refractory Particle 1]

[0182] A molding composition was obtained by adding 0.26% by mass of a curing agent (96% by mass of γ-butyrolactone and 4% by mass of resorcinol) and 1.3% by mass of a water-soluble phenolic resin composition to 100% by mass of Fremantle sand (natural silica sand). The molding composition was used for molding, and the resulting mold was used to cast FC250 material at 1400°C with an S / M ratio of 3.5 (the S / M ratio represents the ratio of the mass of the mold to the mass of the casting). Fremantle sand (natural silica sand) was mixed with the casting sand recovered from the mold after casting to a concentration of 5% by mass and regenerated using a Japanese foundry M-type rotary crusher. This process was repeated more than 5 times to obtain refractory particles 1 with an average particle size of 378 μm.

[0183] [Manufacturing of Refractory Particle 2]

[0184] Except that Fremantle sand (natural silica sand: average particle size 528 μm) added to the recycled casting sand was set to 10% by mass in the manufacture of refractory particles 1, refractory particles 2 with an average particle size of 407 μm were obtained by using the same manufacturing method.

[0185] [Manufacturing of Refractory Particle 3]

[0186] Except that Fremantle sand (natural silica sand) added to the recycled casting sand was not added during the manufacture of refractory particles 1, the same manufacturing method was used to obtain refractory particles 3 with an average particle size of 348 μm.

[0187] [Manufacturing of Refractory Particle 4]

[0188] Except for changing Fremantle sand to ESPEARL #40L (manufactured by Yamakawa Sangyo Co., Ltd.: average particle size 406 μm) in the manufacture of refractory particles 1, the same manufacturing method was used to obtain refractory particles 4 with an average particle size of 396 μm.

[0189] [Manufacturing of Refractory Particle 5]

[0190] Except for changing Fremantle sand to ESPEARL #40L (manufactured by Yamakawa Sangyo Co., Ltd.) in the manufacture of refractory particles 1 and changing the amount of ESPEARL #40L added to the recycled casting sand to 10% by mass, the same manufacturing method was used to obtain refractory particles 5 with an average particle size of 398 μm.

[0191] [Manufacturing of Refractory Particle 6]

[0192] Except that the Fremantle sand was changed to ESPEARL #40L (manufactured by Yamakawa Sangyo Co., Ltd.) in the manufacture of refractory particles 1, and ESPEARL #40L added to the recycled casting sand was not added, the same manufacturing method was used to obtain refractory particles 6 with an average particle size of 390 μm.

[0193] [Refractory Particles 7]

[0194] Fremantle sand (natural silica sand: average particle size 528 μm) was used as refractory particle 7.

[0195] [Refractory Particles 8]

[0196] ESPEARL #40L (manufactured by Yamakawa Sangyo Co., Ltd.) was used as the refractory particle 8.

[0197] <Preparation of the mold composition>

[0198] [Examples 1-1 to 1-13, Comparative Examples 1-1 to 1-6]

[0199] 100 parts by weight of refractory particles 1 and 0.26 parts by weight of the curing agent composition shown in Table 1 were added and mixed for 40 seconds using a mixer (KM-300 benchtop mixer, Aikosha Co., Ltd.). Then, 1.3 parts by weight of the binder composition shown in Table 1 were added and mixed for 40 seconds to obtain the molding composition.

[0200] [Examples 1-14]

[0201] 100 parts by mass of refractory particle 1, 0.0091 parts by mass of the compound of the above general formula (1) (R: lauryl, n=5), 0.0026 parts by mass of oleic acid, and 0.26 parts by mass of the curing agent composition shown in Table 1 were added and mixed for 40 seconds using a mixer (KM-300 benchtop mixer, Aikosha Co., Ltd.). Then, 1.3 parts by mass of the binder composition shown in Table 1 were added and mixed for 40 seconds to obtain the molding composition.

[0202] [Examples 1-15 to 1-21, Comparative Examples 1-7 to 1-13]

[0203] Except for using the refractory particles, binder compositions and curing agent compositions shown in Table 2, the same procedures as in Examples 1-1 were followed to obtain the molding compositions of Examples 1-15 to 1-21 and Comparative Examples 1-7 to 1-13.

[0204] 〔evaluate〕

[0205] The flowability and filling properties of the molding compositions of Examples 1-1 to 1-21 and Comparative Examples 1-1 to 1-13 were evaluated using the following method. The evaluation results are shown in Tables 1 and 2.

[0206] [Liquidity Assessment]

[0207] The freshly mixed molding composition is filled into a vertical cylindrical PVC tube (φ50mm×300mmH) until a mountain-like portion appears on the top of the PVC tube. The sand on the mountain-like portion is scraped off, the PVC tube is lifted, and the width of the spread molding composition (in mm) is measured. The larger the value, the better the fluidity.

[0208] [Infill Density Evaluation]

[0209] The mass of the molding composition in the PVC pipe is determined and calculated based on the pipe's capacity. A higher value indicates a higher filling density and better flowability.

[0210] [Mold Evaluation]

[0211] Using the molding compositions of Examples 1-1 and Comparative Examples 1-1, a mold was prepared by the following method. The freshly mixed molding composition was passed through a sieve with a metal mesh having an aperture of 3.35 mm and a wire diameter of 1.27 mm, and then filled into a wooden mold used for evaluating the smoothness of the mold surface. A cross-sectional view of this wooden mold is shown below. Figure 1 In this process, the molding composition is filled higher than the upper surface of the wooden mold, and excess molding composition on the upper surface of the wooden mold is immediately scraped off to form the mold. After the molding composition within the wooden mold has cured, it is demolded from the wooden mold, and the surface smoothness is observed visually. The appearance of the mold of Example 1-1 is shown in the figure. Figure 2 In the figure, the appearance of the mold of Comparative Example 1-1 is shown. Figure 3 The mold composition of Example 1-1 has improved fluidity and filling density compared to the mold composition of Comparative Example 1-1, resulting in a higher surface smoothness for the mold compared to the mold of Comparative Example 1-1. This reduces mold repairs and significantly improves casting quality.

[0212] [Casting Quality Evaluation]

[0213] The method for evaluating casting quality will be explained with reference to the accompanying drawings. First, a master mold is made using the mold composition of Comparative Example 1-1. Figure 4 This is a schematic diagram showing a cross-section of the master mold 1, where symbol 11 represents the inner wall of the master mold 1 and symbol 12 represents a cross-section of the master mold 1. In this master mold 1, a mold 2 of Example 1-1 or Comparative Example 1-1, which was made for mold evaluation, is provided. Figure 5 This is a schematic cross-sectional view showing the state in which mold 2 is set in the main mold 1. Then, as... Figure 6 As shown, 17 kg of molten metal material FC200 is poured into the main mold 1, which is equipped with mold 2, at 1400°C to produce casting 3. Figure 7 It means from Figure 6 The diagram shows a cross-section 3 of the casting 3 (without the main mold 1 and mold 2) and a schematic diagram of the inner wall 3 (the surface in contact with the mold 2) 31 of the casting 3, which are in the state shown in the diagram. A photograph of the appearance of the inner wall 11 of the casting 3 manufactured in Example 1-1 is shown in the diagram. Figure 8 In the figure, a photograph of the appearance of the inner wall 11 of casting 3 of Comparative Example 1-1 is shown. Figure 9 Compared with the mold composition of Comparative Example 1-1, the mold composition of Example 1-1 has improved fluidity, filling density, and high mold smoothness. Therefore, the surface of the inner wall 11 of the casting 3 of Example 1-1 is smoother than the surface of the inner wall 11 of the casting 3 of Comparative Example 1-1. As a result, the need for casting repair can be reduced, and the casting quality is greatly improved.

[0214] [Table 1]

[0215]

[0216] [Table 2]

[0217]

[0218] The molding compositions of the examples exhibit superior flowability and filling density compared to the molding compositions of the comparative examples. In particular, as shown in Comparative Examples 1-1 and 1-2, Comparative Examples 1-3 and 1-4, even with an increase in the content of the compound of the above general formula (1) and the above fatty acid, the flowability and filling density do not improve. However, as shown in Examples 1-1 to 1-14, by combining the compound of the above general formula (1) with the above fatty acid, the flowability and filling density are improved.

[0219] [Examples 2-1 to 2-12, Comparative Example 2-1]

[0220] As shown in Table 3, the foaming and storage stability were evaluated using the curing agent compositions used in Examples 1-1 to 1-12 and the adhesive compositions used in Examples 1-13.

[0221] [Foaming Evaluation]

[0222] Add the binder composition or curing agent composition listed in the table to a 50ml transparent glass container, and shake and stir for 10 seconds using a YAMATO Scientific MT-31 touch stirrer. After 1 minute, visually check for the presence or absence of air bubbles.

[0223] [Preservation Stability]

[0224] After storage at 25°C for 3 days, liquid separation was performed, and the presence or absence of insoluble matter and turbidity was visually confirmed. The evaluation results are shown in Table 3.

[0225] [Table 3]

[0226]

[0227] The curing compositions of Examples 2-1 to 2-12, which incorporate the compound of Formula (1) and fatty acid into the curing composition, do not produce bubbles and exhibit excellent storage stability compared to the adhesive composition of Comparative Example 2-1, which incorporates the compound of Formula (1) and fatty acid into the adhesive composition.

Claims

1. A method for manufacturing a molding composition, the method comprising the steps of mixing refractory particles, a molding binder composition containing phenolic resin, and a molding curing agent composition. The curing agent composition for molding contains a curing agent, a compound represented by the following general formula (1), and a fatty acid with 8 or more carbon atoms and 22 or fewer carbon atoms; The ratio of the content of fatty acids in the curing agent composition for molding to the total content of the compound represented by general formula (1) and the fatty acids, i.e., the content of fatty acids / (the total content of the compound represented by general formula (1) and the fatty acids) is 0.05 or more and 0.6 or less. RO-(CH2CH2O)nH (1) In the general formula (1), R represents an alkyl or alkenyl group with 8 or more carbon atoms and 22 or less in the straight or branched chain, n represents the average number of addition moles, and n represents a number of 1.2 or more and 23 or less.

2. The method for manufacturing the molding composition according to claim 1, wherein, The compound represented by the general formula (1) comprises a compound in which R represents an alkyl or alkenyl group with 10 or more and 20 or less carbon atoms in a straight chain, and n represents a number of 1.8 or more and 13 or less.

3. The method for manufacturing the mold composition according to claim 1 or 2, wherein, The content of the compound represented by the general formula (1) in the curing agent composition for molding is more than 1% by mass and less than 10% by mass.

4. The method for manufacturing the mold composition according to claim 1 or 2, wherein, The content of the compound represented by the general formula (1) in the curing agent composition for molding is 2% by mass or more and 5% by mass or less.

5. The method for manufacturing the mold composition according to claim 1 or 2, wherein, The fatty acids include fatty acids with a melting point below 45°C.

6. The method for manufacturing the mold composition according to claim 1 or 2, wherein, The fatty acids include one or more selected from oleic acid, linolenic acid, linoleic acid, and lauric acid.

7. The method for manufacturing the mold composition according to claim 1 or 2, wherein, The content of the fatty acid in the curing agent composition for molding is 0.1% by mass or more and 6% by mass or less.

8. The method for manufacturing the mold composition according to claim 1 or 2, wherein, The content of the fatty acid in the curing agent composition for molding is 0.3% by mass or more and 3% by mass or less.

9. The method for manufacturing the mold composition according to claim 1 or 2, wherein, The curing agent content in the curing agent composition for molding is 60% by mass or more and 99% by mass or less.

10. The method for manufacturing the mold composition according to claim 1 or 2, wherein, The ratio of the content of fatty acids in the curing agent composition for molding to the total content of the compound represented by the general formula (1) and the fatty acids, i.e., the content of fatty acids / (the total content of the compound represented by the general formula (1) and the fatty acids) is 0.1 or more and 0.4 or less.

11. The method for manufacturing the mold composition according to claim 1 or 2, wherein, The phenolic resin is a water-soluble phenolic resin, and the content of the water-soluble phenolic resin in the adhesive composition for casting is more than 40% by mass and less than 60% by mass.

12. A curing agent composition for casting molds, It contains a curing agent, a compound represented by the following general formula (1), and a fatty acid with 8 or more carbon atoms and 22 or fewer; The ratio of the content of the fatty acid to the total content of the compound represented by the general formula (1) and the fatty acid, i.e., the content of the fatty acid / (the total content of the compound represented by the general formula (1) and the fatty acid) is 0.05 or more and 0.6 or less. RO-(CH2CH2O)nH (1) In the general formula (1), R represents an alkyl or alkenyl group with 8 or more carbon atoms and 22 or less in the straight or branched chain, n represents the average number of addition moles, and n represents a number of 1.2 or more and 23 or less.

13. The curing agent composition for molding according to claim 12, wherein, The content of the fatty acid is 0.1% by mass or more and 6% by mass or less.

14. The curing agent composition for molding according to claim 12 or 13, wherein, The fatty acids include fatty acids with a melting point below 45°C.

15. The curing agent composition for molding according to claim 12 or 13, wherein, The fatty acids include one or more selected from oleic acid, linolenic acid, linoleic acid, and lauric acid.

16. The curing agent composition for molding according to claim 12 or 13, wherein, The content of the compound represented by the general formula (1) is more than 1% by mass and less than 10% by mass.

17. The curing agent composition for molding according to claim 12 or 13, wherein, The content of the compound represented by the general formula (1) is more than 2% by mass and less than 5% by mass.

18. The curing agent composition for molding according to claim 12 or 13, wherein, The ratio of the content of fatty acids to the total content of the compound represented by the general formula (1) and the fatty acids, i.e., the content of fatty acids / (the total content of the compound represented by the general formula (1) and the fatty acids) is 0.1 or more and 0.4 or less.

19. The curing agent composition for molding according to claim 12 or 13, wherein, The content of the curing agent is 60% by mass or more and 99% by mass or less.

20. The curing agent composition for molding according to claim 12 or 13, wherein, The content of the curing agent is 85% by mass or more and 97% by mass or less.

21. A molding composition, It is made by mixing refractory particles, a phenolic resin-containing adhesive composition for molding, and a curing agent composition for molding. The curing agent composition for molding contains a curing agent, a compound represented by the following general formula (1), and a fatty acid with 8 or more carbon atoms and 22 or fewer carbon atoms; The ratio of the content of the fatty acids to the total content of the compound represented by the general formula (1) is 0.05 or more and 0.6 or less. RO-(CH2CH2O)nH (1) In the general formula (1), R represents an alkyl or alkenyl group with 8 or more carbon atoms and 22 or less in the straight or branched chain, n represents the average number of addition moles, and n represents a number of 1.2 or more and 23 or less.

22. The molding composition according to claim 21, wherein, The content of the phenolic resin is 0.1 parts by mass and less than 5 parts by mass relative to 100 parts by mass of the refractory particles.

23. The molding composition according to claim 21 or 22, wherein, The content of the compound represented by the general formula (1) is more than 0.001 parts by mass and less than 0.1 parts by mass relative to 100 parts by mass of the refractory particles.

24. The molding composition according to claim 21 or 22, wherein, The compound represented by the general formula (1) comprises a compound in which R represents an alkyl or alkenyl group with 10 or more and 20 or less carbon atoms in a straight chain, and n represents a number of 1.8 or more and 13 or less.

25. The molding composition according to claim 21 or 22, wherein, The content of the fatty acid is 0.0005 parts by mass or more and 0.05 parts by mass or less per 100 parts by mass of the refractory particles.

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