Binding agent composition, sand composition, mold molding kit, and method for manufacturing a mold.

Abstract

To provide a binder composition, a sand composition, a mold-making kit, and a method for manufacturing a mold, all of which fall under the category of non-hazardous materials under the Fire Service Act and are capable of producing molds of practical strength. [Solution] A binder composition comprising (A) component: furfuryl alcohol, (B) component: furan resin, or a condensate of urea and aldehydes, (C) component: 5-hydroxymethylfurfural, and (D) component: water, wherein the content of component (C) is 0.1 to 40% by mass and the content of component (D) is 16.0 to 18.7% by mass, based on the total mass of the binder composition.

Description

Technical Field

[0001] The present invention relates to a binder composition, a sand composition, a kit for mold molding, and a method for manufacturing a mold.

Background Art

[0002] Conventionally, a self-hardening mold is known as one of the casting molds (hereinafter, also simply referred to as "mold"). A self-hardening mold is obtained by adding and kneading a binder (acid-curable binder) mainly composed of a furan resin or the like and an acid catalyst (hardening agent) such as sulfuric acid or xylene sulfonic acid to a refractory granular material such as silica sand, and then filling the obtained sand composition (kneaded sand) into a wooden mold, a resin mold, a metal mold, etc. (hereinafter, these are collectively also referred to as "mold for mold molding") and curing the binder.

[0003] Binders containing furan resin are classified into dangerous goods (Class 4, Third Petroleum) and non-dangerous goods defined by the Fire Service Act. When using a binder classified as a dangerous good, approval of a dangerous goods handling facility and a dangerous goods storage facility is required. Therefore, a non-dangerous binder must be used for manufacturing a mold at an unapproved location.

[0004] The classification of dangerous goods is determined by whether a flash point is recognized. In the case of a binder containing furan resin, whether a flash point is recognized is determined by the moisture content in the binder. Therefore, by adjusting the moisture content in the binder, specifically by adding water to the furan resin to make the moisture content 18% by mass or more, the binder is made non-dangerous. However, when the moisture content in the binder increases, the amount of the active ingredient as the binder decreases. Therefore, when using a binder corresponding to non-dangerous goods, the strength of the mold is likely to decrease compared to when using a binder corresponding to dangerous goods.

[0005] So far, binder compositions have been proposed that improve mold strength while considering the working environment by blending 5-hydroxymethylfurfural with furfuryl alcohol or blending bishydroxymethylfuran with furan resin (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2015-131343 [Patent Document 2] Patent No. 7102639 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] However, it is not mentioned that the binder compositions described in Patent Documents 1 and 2 are non-hazardous materials. The present invention aims to provide a binder composition, a sand composition, a mold-making kit, and a method for manufacturing a mold, all of which fall under the category of non-hazardous materials under the Fire Service Act and are capable of producing molds with practical strength. [Means for solving the problem]

[0008] The present invention has the following aspects. [1] (A) Components: Furfuryl alcohol and (B) Components: Furan resin, or a condensate of urea and aldehydes, (C) Ingredients: 5-hydroxymethylfurfural and (D) Ingredients: Water and A binder composition containing, A binder composition wherein the content of component (C) is 0.1 to 40% by mass and the content of component (D) is 16.0 to 18.7% by mass, relative to the total mass of the binder composition. [2] A sand composition comprising the binder composition described in [1] above, a fire-resistant granular material, and a hardening agent. [3] A mold-making kit comprising, independently, the binder composition described in [1] above, a refractory granular material, and a hardening agent. [4] A mold-making kit comprising, independently, the binder composition described in [1] above and a refractory granular material containing a hardening agent. [5] A method for manufacturing a mold, comprising filling a mold for manufacturing a mold with the sand composition described in [2] above, and hardening the binder composition contained in the sand composition. [6] A method for manufacturing a mold by three-dimensional additive manufacturing, (a) A step of laying a mixture containing fire-resistant granular material and a hardening agent in layers, The step (b) involves injecting the binder composition described in [1] into a desired region of the layered mixture, A method for manufacturing a mold, comprising repeating the above steps (a) and (b) until the desired mold is formed. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a binder composition, a sand composition, a mold-making kit, and a method for manufacturing a mold that fall under the category of non-hazardous materials under the Fire Service Act and can produce a mold with practical strength. [Modes for carrying out the invention]

[0010] The following describes in detail embodiments for carrying out the present invention, but the present invention is not limited to the embodiments described later, and various modifications are possible as long as they do not depart from the spirit of the present invention. In this specification and in the claims, a numerical range represented by "~" means a numerical range that includes the numbers before and after "~" as the lower and upper limits, respectively. For example, A~B is synonymous with A or greater and B or less. The numerical ranges of the content, various physical properties, and characteristic values ​​disclosed herein can be modified by arbitrarily combining their lower and upper limits to create new numerical ranges. In the following specification, "mold" refers to a mold formed using the binder composition, sand composition, or mold-making kit of the present invention. Furthermore, "strength" refers to the strength of the mold at room temperature.

[0011] [Binding agent composition] Hereinafter, an embodiment of the binder composition (X) according to the first aspect of the present invention will be described. The binder composition (X) of the present embodiment contains the following components (A) to (D). The binder composition (X) may further contain components other than the components (A) to (D) (hereinafter, also referred to as "optional components") as necessary, as long as the effects of the present invention are not impaired. Component (A): Furfuryl alcohol Component (B): A furan resin or a condensate of urea and aldehydes Component (C): 5-Hydroxymethylfurfural Component (D): Water

[0012] Hereinafter, the binder composition (hereinafter, also referred to as "binder composition (X1)") when containing a furan resin (hereinafter, also referred to as "(B1) component") as the component (B) is taken as the first embodiment of the binder composition (X), and the binder composition (hereinafter, also referred to as "binder composition (X2)") when containing a condensate of urea and aldehydes (hereinafter, also referred to as "(B2) component") as the component (B) is taken as the second embodiment of the binder composition (X), and an example of each embodiment will be described respectively.

[0013] "First Embodiment" The binder composition (X1) of the first embodiment contains the following component (A), component (B1), component (C), and component (D), and may further contain optional components as necessary. Hereinafter, each component will be described.

[0014] <Component (A)> Component (A) is furfuryl alcohol. The content of component (A) is preferably 30% by mass or more, more preferably 35% by mass or more, still more preferably 40% by mass or more, and preferably 60% by mass or less, more preferably 55% by mass or less, still more preferably 50% by mass or less, based on the total mass of the binder composition (X1). If the content of component (A) is at least the above lower limit value, the kneadability with the refractory granular material is improved. If the content of component (A) is at most the above upper limit value, it is likely to be in a situation without a flash point. The above upper and lower limits of the content of component (A) can be arbitrarily combined. For example, the content of component (A) is preferably 30 to 60% by mass, more preferably 35 to 55% by mass, and even more preferably 40 to 50% by mass based on the total mass of the binder composition (X1). The content of component (A) is the amount in terms of pure content.

[0015] <Component (B1)> Component (B1) is a furan resin. The furan resin is a resin mainly made of furfuryl alcohol, urea, formaldehyde, etc., and undergoes polycondensation and curing while undergoing dehydration reaction with an acid catalyst. Particularly preferred embodiments of the furan resin include, for example, the following. (1) A condensate of furfuryl alcohol, urea, and aldehydes. (2) A condensate of furfuryl alcohol and urea. (3) A condensate of furfuryl alcohol, ethylene urea, and aldehydes. (4) A condensate of furfuryl alcohol and ethylene urea. (5) A condensate of furfuryl alcohol, at least one of phenols and bisphenols, and aldehydes. (6) A condensate of furfuryl alcohol and aldehydes. (7) A condensate of furfuryl alcohol, melamine, and aldehydes. (8) A condensate of furfuryl alcohol and melamine.<( (9) A condensate of furfuryl alcohol. These furan resins may be used alone or in combination of two or more. As the furan resin, the embodiment of (1) is preferred.

[0016] Examples of aldehydes include formaldehyde, paraformaldehyde, acetaldehyde, furfural, glyoxal, glutardialdehyde, and phthalate dialdehyde. These aldehydes may be used individually or in combination of two or more. However, depending on the type of condensate, acid hardening may not proceed when glyoxal or furfural are used alone as aldehydes. In such cases, at least formaldehyde should be used as the aldehyde.

[0017] Examples of phenols include phenol, cresol, resorcinol, nonylphenol, and cashew nut shell liquid (CNSL). These phenols may be used individually or in combination of two or more. Examples of bisphenols include bisphenol A, bisphenol F, bisphenol C, bisphenol S, bisphenol E, and bisphenol Z. These bisphenols may be used individually or in combination of two or more.

[0018] Commercially available furan resin may be used. Commercially available furan resins are typically sold as a mixture containing water (hereinafter also referred to as "furan resin mixture (M1)"). The furan resin mixture (M1) may optionally contain furan resin raw materials such as furfuryl alcohol, and optional components such as silane coupling agents. When using commercially available furan resins, it is preferable to use furan resins classified as non-hazardous materials under the Fire Service Act, that is, furan resin mixture (M1) with a water content of 18% by mass or more.

[0019] Furthermore, furan resin may be manufactured by known methods. Furan resin can be obtained by general manufacturing methods. One example is shown below. First, a portion of the raw materials for furan resin (furfuryl alcohol, aldehydes, urea, etc.) is mixed with an aqueous sodium hydroxide solution to make it alkaline, and the temperature is raised to produce adducts with the aldehydes. Next, the reaction solution is made acidic using hydrochloric acid, etc., and the condensation of furfuryl alcohol, urea, and aldehydes proceeds. Then, the reaction solution is made alkaline again, and the remaining raw materials for furan resin, along with a silane coupling agent if necessary, are mixed to obtain a mixture containing furan resin, water, and optionally a silane coupling agent (hereinafter also referred to as "furan resin mixture (M2)"). The furan resin mixture (M2) may contain unreacted raw materials (furfuryl alcohol, aldehydes, urea, etc.).

[0020] The water content (moisture content) in the furan resin mixture (M2) is not particularly limited, but from the viewpoint of being able to treat the furan resin mixture (M2) as a non-hazardous material under the Fire Service Act, it is preferable that the water content be 18% by mass or more relative to the total mass of the furan resin mixture (M2). If the moisture content of the furan resin mixture (M2) is less than 18% by mass, it is preferable to add more water to the furan resin mixture (M2) to adjust the moisture content so that the moisture content is 18% by mass or more.

[0021] The content of component (B1) is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 35% by mass or less, based on the total mass of the binder composition (X1). If the content of component (B1) is above the lower limit, the mold strength will be further increased. If the content of component (B1) is below the upper limit, the increase in viscosity of the binder composition (X1) will be suppressed and good kneadability can be maintained. The above upper and lower limits for the content of component (B1) can be combined arbitrarily. For example, the content of component (B1) is preferably 5 to 50% by mass, more preferably 10 to 45% by mass, and even more preferably 15 to 35% by mass, based on the total mass of the binder composition (X1). (B1) The content of component is expressed on a pure content basis.

[0022] <(C) component> (C) The component is 5-hydroxymethylfurfural (HMF). The presence of component (C) in the binder composition (X1) reduces the amount of component (D), i.e., water, in the binder composition (X1) compared to a case where component (C) is not present, by the amount of component (C) added to the binder composition (X1). For example, when the binder composition (X1) is produced by mixing the above-mentioned furan resin mixture (M1) or furan resin mixture (M2) with component (C), the water content of the resulting binder composition (X1) is reduced by the amount of component (C) added, compared to the water content of the furan resin mixture (M1) or furan resin mixture (M2). Therefore, even when using furan resin mixture (M1) or furan resin mixture (M2), which are classified as non-hazardous materials under the Fire Service Act, the water content of the resulting binder composition (X1) can be reduced, thereby suppressing a decrease in the strength of the mold.

[0023] The content of component (C) is 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 1% by mass or more, even more preferably 1.5% by mass or more, particularly preferably 3% by mass or more, most preferably 5% by mass or more, and also 40% by mass or less, preferably 35% by mass or less, more preferably less than 35% by mass, even more preferably 30% by mass or less, particularly preferably 25% by mass or less, and most preferably 20% by mass or less. If the content of component (C) is above the lower limit above, a binder composition (X1) that is classified as a non-hazardous material under the Fire Service Act and can produce a mold with practical strength can be obtained. If the content of component (C) is below the upper limit above, the binder composition (X1) can maintain its non-hazardous material status in good condition. In addition, the increase in manufacturing costs for the binder composition (X1) and the mold can be suppressed. The above upper and lower limits for the content of component (C) can be combined arbitrarily. For example, the content of component (C) is 0.1 to 40% by mass of the total mass of the binder composition (X1), preferably 0.5 to 35% by mass, more preferably 1% by mass or more and less than 35% by mass, even more preferably 1.5 to 30% by mass, particularly preferably 3 to 25% by mass, and most preferably 5 to 20% by mass. (C) The content of component is expressed on a pure content basis.

[0024] Furthermore, the total content of components (A), (B1), and (C) is preferably 79.5 to 84.0% by mass, more preferably 80.0 to 83.5% by mass, and even more preferably 80.5 to 82.5% by mass, based on the total mass of the binder composition (X1).

[0025] <(D) component> (D) Component is water. The content of component (D) is 16.0% by mass or more, preferably 16.5% by mass or more, and 18.7% by mass or less, preferably 18.5% by mass or less, and more preferably 18.0% by mass, based on the total mass of the binder composition (X1). If the content of component (D) is above the lower limit, the binder composition (X1) can maintain a good state as a non-hazardous material. If the water content is below the upper limit, the strength of the mold can be maintained well. The above upper and lower limits for the content of component (D) can be combined arbitrarily. For example, the content of component (D) is 16.0 to 18.7% by mass, preferably 16.5 to 18.5% by mass, and more preferably 16.5 to 18.0% by mass, relative to the total mass of the binder composition (X1).

[0026] The total content of component (C) and component (D) is preferably 18.0 to 58.0% by mass, more preferably 18.0 to 40.0% by mass, and even more preferably 20.0 to 33.5% by mass, relative to the total mass of the binder composition (X1). If the total content of component (C) and component (D) is within the above range, the binder composition (X1) can maintain a non-hazardous state more effectively while maintaining the strength of the mold more effectively.

[0027] <Optional ingredients> Optional components include, for example, silane coupling agents, formaldehyde scavenging agents, and organic solvents. These optional components may be used individually or in combination of two or more.

[0028] If the binder composition (X1) contains a silane coupling agent, the strength of the mold is further improved. Examples of silane coupling agents include N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, 3-(2-aminoethyl)aminopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 3-glycidoxypropyltriethoxysilane. These silane coupling agents may be used individually or in combination of two or more. The silane coupling agent content is preferably 0.01 to 1.0% by mass, more preferably 0.05 to 0.5% by mass, and even more preferably 0.1 to 0.4% by mass, relative to the total mass of the binder composition (X1).

[0029] Examples of formaldehyde scavenging agents include urea, resorcinol, and pyrogallol. These formaldehyde scavenging agents may be used individually or in combination of two or more. Examples of organic solvents include methanol, ethanol, 1-propanol, 2-propanol, and other alcohols. These organic solvents may be used individually or in combination of two or more.

[0030] <Manufacturing method> The binder composition (X1) is obtained by mixing component (A), component (B1), component (C), component (D), and any optional component in a desired proportion. There are no particular limitations on the mixing method, as long as it is a general mixing method; for example, methods using a stirrer can be used.

[0031] Alternatively, a mixture (hereinafter also referred to as "furan resin mixture (M3)") may be prepared by mixing component (A), component (B1), component (D), and any optional component as needed, and the binder composition (X1) may be produced by mixing the furan resin mixture (M3) with component (C). Alternatively, a mixture (hereinafter also referred to as "HMF mixture (M4)") may be prepared separately by mixing component (C), component (D), and one or more optional components, and the binder composition (X1) may be produced by mixing the furan resin mixture (M3) with the HMF mixture (M4).

[0032] From the viewpoint of being able to treat the furan resin mixture (M3) as a non-hazardous material under the Fire Service Act, the content (moisture content) of component (D) in the furan resin mixture (M3) is preferably 18.0% by mass or more, more preferably 18.0 to 18.7% by mass, and even more preferably 18.0 to 18.5% by mass, relative to the total mass of the furan resin mixture (M3). If the moisture content of the furan resin mixture (M3) is less than 18% by mass, it is preferable to further add component (D) as needed to adjust the moisture content so that the moisture content in the binder composition (X1) is 16.5 to 18.7% by mass when mixing it with component (C) or the HMF mixture (M4) to form a binder composition (X1). If the furan resin mixture (M1) or furan resin mixture (M2) described above contains unreacted component (A), the furan resin mixture (M1) or furan resin mixture (M2) may be used as the furan resin mixture (M3).

[0033] <Effects and Effects> As described above, the binder composition (X1) of this embodiment contains 5-hydroxymethylfurfural, which is component (C). Therefore, the amount of water, which is component (D), in the binder composition (X1) is reduced by the amount of component (C) added to the binder composition (X1). Thus, a decrease in the strength of the mold can be suppressed. Furthermore, although 5-hydroxymethylfurfural itself has a flash point, when the flash point is measured for the binder composition (X1) containing component (C), 5-hydroxymethylfurfural boils, and therefore is considered to have no flash point. Since the binder composition (X1) containing specific amounts of components (C) and (D) has no flash point, it is considered to be a non-hazardous material under the Fire Service Act (i.e., it does not fall under Class 4, Third Petroleum as defined by the Fire Service Act). Therefore, the binder composition (X1) of this embodiment is easy to handle, and using the binder composition (X1) of this embodiment, molds can be easily manufactured even in places without authorization as a hazardous materials handling facility or hazardous materials storage facility.

[0034] In particular, when manufacturing a binder composition (X1) using one of the above-mentioned furan resin mixtures (M1), (M2), or (M3) that falls under the category of non-hazardous materials under the Fire Service Act, mixing any of these furan resin mixtures with component (C) or the above-mentioned HMF mixture (M4) allows for the reduction of the overall water content of the binder composition (X1) by the amount of component (C) added, while maintaining the non-hazardous state of the furan resin mixture. This makes it possible to easily manufacture a binder composition (X1) that falls under the category of non-hazardous materials under the Fire Service Act while being capable of producing molds with practical strength.

[0035] "Second Embodiment" The binder composition (X2) of the second embodiment contains component (A), component (B2), component (C), and component (D) as shown below, and may further contain any optional components as needed. The following describes each component.

[0036] <(A) component> (A) The component is furfuryl alcohol. (A) The content of component (A) is preferably 30% by mass or more, more preferably 35% by mass or more, even more preferably 40% by mass or more, and preferably 60% by mass or less, more preferably 55% by mass or less, and even more preferably 50% by mass or less, based on the total mass of the binder composition (X2). If the content of component (A) is above the lower limit above, the kneadability with the refractory granular material is improved. If the content of component (A) is below the upper limit above, it is less likely to result in a situation where there is no flash point. The above upper and lower limits for the content of component (A) can be combined in any way. For example, the content of component (A) is preferably 30 to 60% by mass, more preferably 35 to 55% by mass, and even more preferably 40 to 50% by mass, based on the total mass of the binder composition (X2). (A) The content of each component is expressed on a pure content basis.

[0037] <(B2) component> Component (B2) is a condensate of urea and aldehydes. Examples of aldehydes include those previously exemplified in the description of component (B1). Formaldehyde is particularly preferred.

[0038] The content of component (B2) is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 35% by mass or less, based on the total mass of the binder composition (X2). If the content of component (B2) is above the lower limit above, the mold strength will be further increased. If the content of component (B2) is below the upper limit above, the increase in viscosity of the binder composition (X2) will be suppressed and good kneadability will be maintained. The above upper and lower limits for the content of component (B2) can be combined arbitrarily. For example, the content of component (B2) is preferably 5 to 50% by mass, more preferably 10 to 45% by mass, and even more preferably 15 to 35% by mass, based on the total mass of the binder composition (X2). (B2) The content of component is expressed on a pure content basis.

[0039] <(C) component> (C) The component is 5-hydroxymethylfurfural (HMF). The presence of component (C) in the binder composition (X2) reduces the amount of component (D), i.e., water, in the binder composition (X2) compared to a case where component (C) is not present, by the amount of component (C) added to the binder composition (X2). As will be explained in more detail later, for example, if a mixture (hereinafter also referred to as "resin mixture (M5)") is prepared in advance by mixing component (A), component (B2), component (D), and any optional component as needed, and the binder composition (X2) is manufactured by mixing the resin mixture (M5) with component (C), etc., the water content of the resulting binder composition (X2) will be reduced compared to the water content of the resin mixture (M5) by the amount of component (C) added. Therefore, even if a resin mixture (M5) that falls under the category of non-hazardous materials under the Fire Service Act is used, the water content of the resulting binder composition (X2) can be reduced, thereby suppressing a decrease in the strength of the mold.

[0040] The content of component (C) is 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 1% by mass or more, even more preferably 1.5% by mass or more, particularly preferably 3% by mass or more, most preferably 5% by mass or more, and also 40% by mass or less, preferably 35% by mass or less, more preferably less than 35% by mass, even more preferably 30% by mass or less, particularly preferably 25% by mass or less, and most preferably 20% by mass or less. If the content of component (C) is above the lower limit above, a binder composition (X2) that is classified as a non-hazardous material under the Fire Service Act and can produce a mold with practical strength can be obtained. If the content of component (C) is below the upper limit above, the binder composition (X2) can maintain its non-hazardous material status in good condition. In addition, the increase in manufacturing costs for the binder composition (X2) and the mold can be suppressed. The above upper and lower limits for the content of component (C) can be combined arbitrarily. For example, the content of component (C) is 0.1 to 40% by mass of the total mass of the binder composition (X2), preferably 0.5 to 35% by mass, more preferably 1% by mass or more and less than 35% by mass, even more preferably 1.5 to 30% by mass, particularly preferably 3 to 25% by mass, and most preferably 5 to 20% by mass. (C) The content of component is expressed on a pure content basis.

[0041] Furthermore, the total content of components (A), (B2), and (C) is preferably 79.5 to 84.0% by mass, more preferably 80.0 to 83.5% by mass, and even more preferably 80.5 to 82.5% by mass, based on the total mass of the binder composition (X2).

[0042] <(D) component> (D) Component is water. The content of component (D) is 16.0% by mass or more, preferably 16.5% by mass or more, and 18.7% by mass or less, preferably 18.5% by mass or less, and more preferably 18.0% by mass, based on the total mass of the binder composition (X2). If the content of component (D) is above the lower limit, the binder composition (X2) can maintain a good state as a non-hazardous material. If the water content is below the upper limit, the strength of the mold can be maintained well. The above upper and lower limits for the content of component (D) can be combined arbitrarily. For example, the content of component (D) is 16.0 to 18.7% by mass, preferably 16.5 to 18.5% by mass, and more preferably 16.5 to 18.0% by mass, based on the total mass of the binder composition (X2).

[0043] The total content of component (C) and component (D) is preferably 18.0 to 58.0% by mass, more preferably 18.0 to 40.0% by mass, and even more preferably 20.0 to 33.5% by mass, relative to the total mass of the binder composition (X2). If the total content of component (C) and component (D) is within the above range, the binder composition (X2) can maintain a non-hazardous state more effectively while maintaining the strength of the mold more effectively.

[0044] <Optional ingredients> Examples of optional components include those previously exemplified in the description of the first embodiment. Furthermore, the content of optional components in the binder composition (X2) is the same as in the case of the binder composition (X1) of the first embodiment. The optional components may be used individually or in combination of two or more.

[0045] <Manufacturing method> The binder composition (X2) is obtained by mixing component (A), component (B2), component (C), component (D), and any optional component in a desired proportion. There are no particular limitations on the mixing method, as long as it is a general mixing method; for example, methods using a stirrer can be used.

[0046] Alternatively, a resin mixture (M5) may be prepared by mixing component (A), component (B2), component (D), and any optional component as needed, and a binder composition (X2) may be produced by mixing the resin mixture (M5) with component (C). Alternatively, an HMF mixture (M4) may be prepared separately, and the binder composition (X2) may be produced by mixing the resin mixture (M5) with the HMF mixture (M4).

[0047] From the viewpoint of being able to treat the resin mixture (M5) as a non-hazardous material under the Fire Service Act, the content (moisture content) of component (D) in the resin mixture (M5) is preferably 18.0% by mass or more, more preferably 18.0 to 18.7% by mass, and even more preferably 18.0 to 18.5% by mass, relative to the total mass of the resin mixture (M5). If the moisture content of the resin mixture (M5) is less than 18% by mass, it is preferable to further add component (D) as needed to adjust the moisture content so that the moisture content in the binder composition (X2) is 16.5 to 18.7% by mass when mixing it with component (C) or the HMF mixture (M4) to form a binder composition (X2).

[0048] <Effects and Effects> As described above, the binder composition (X2) of this embodiment contains 5-hydroxymethylfurfural, which is component (C). Therefore, the amount of water, which is component (D), in the binder composition (X2) is reduced by the amount of component (C) added to the binder composition (X2). Thus, a decrease in the strength of the mold can be suppressed. Furthermore, although 5-hydroxymethylfurfural itself has a flash point, when the flash point is measured for the binder composition (X2) containing component (C), 5-hydroxymethylfurfural boils, and therefore is considered to have no flash point. Since the binder composition (X2) containing specific amounts of components (C) and (D) has no flash point, it is considered to be a non-hazardous material under the Fire Service Act (i.e., it does not fall under Class 4, Third Petroleum as defined by the Fire Service Act). Therefore, the binder composition (X2) of this embodiment is easy to handle, and using the binder composition (X2) of this embodiment, molds can be easily manufactured even in places without authorization as a hazardous materials handling facility or hazardous materials storage facility.

[0049] In particular, when manufacturing a binder composition (X2) using the resin mixture (M5) described above that falls under the category of non-hazardous materials under the Fire Service Act, by mixing the resin mixture (M5) with component (C) or the HMF mixture (M4) described above, the moisture content of the binder composition (X2) as a whole can be reduced by the amount of component (C) added, while maintaining the non-hazardous state of the resin mixture (M5). This makes it possible to easily manufacture a binder composition (X2) that falls under the category of non-hazardous materials under the Fire Service Act while being capable of producing molds with practical strength.

[0050] [Sand composition] Hereinafter, an embodiment of the sand composition according to a second aspect of the present invention will be described. The sand composition of this embodiment comprises the binder composition (X) of the first aspect of the present invention described above, a fire-resistant granular material, and a hardening agent. The sand composition may, if necessary, further contain other components (hereinafter also referred to as "optional components") in addition to the binder composition (X), the refractory granular material, and the hardening agent, as long as the effects of the present invention are not impaired.

[0051] <Fire-resistant granular material> As refractory granular materials, conventionally known materials can be used, such as natural sands like silica sand, chromite sand, zircon sand, olivine sand, amorphous silica, alumina sand, and mullite sand; and artificial sands obtained by melting (melting-type artificial sand), flame-melting (flame-type artificial sand), and sintering (sintering-type artificial sand). In addition, recovered refractory granular materials (recovered sand) and recycled sand can also be used. From the viewpoint of manufacturing cost, natural sand is preferred, and among them, silica sand is more preferred. From the viewpoint of not expanding easily with heat, artificial sand is preferred. Considering the balance between manufacturing cost and heat resistance, natural sand and artificial sand may be mixed and used. These fire-resistant granular materials may be used individually or in combination of two or more types. Fire-resistant granular material may be coated with a hardening agent. Fire-resistant granular material coated with a hardening agent is also called "coated sand."

[0052] The average particle size of the refractory granular material is preferably 50 to 600 μm, more preferably 100 to 550 μm, and even more preferably 200 to 500 μm. If the average particle size of the refractory granular material is above the lower limit, it is easier to obtain a mold with high strength. If the average particle size of the refractory granular material is below the upper limit, the castings cast using the mold will have excellent surface quality. The average particle size of refractory granular material is the particle size (median diameter) corresponding to the 50% cumulative frequency based on the volume distribution of the refractory granular material, as measured by dynamic light scattering.

[0053] <Binding agent composition (X)> The content of the binder composition (X) is preferably 0.5 to 3.0 parts by mass, more preferably 0.5 to 2.0 parts by mass, and even more preferably 0.8 to 1.5 parts by mass, per 100 parts by mass of the refractory granular material. If the content of the binder composition (X) is above the lower limit, it is easier to obtain a mold with high strength. If the content of the binder composition (X) is below the upper limit, uneven mixing is less likely to occur. In this specification, "content of binder composition (X)" refers to the mass in its present form, that is, the total amount of all components contained in binder composition (X).

[0054] <Hardening agent> The hardening agent acts as a catalyst for hardening the binder composition (X) during the manufacturing of the mold. Examples of curing agents include inorganic acids such as sulfuric acid, phosphoric acid, and hydrochloric acid; and organic acids such as sulfonic acid and carboxylic acid. These hardening agents may be used individually or in combination of two or more types.

[0055] Examples of sulfonic acids include p-toluenesulfonic acid, xylenesulfonic acid, benzenesulfonic acid, and methanesulfonic acid. These sulfonic acids may be used individually or in combination of two or more. Examples of carboxylic acids include lactic acid, citric acid, malic acid, tartaric acid, malonic acid, succinic acid, maleic acid, oxalic acid, acetic acid, and benzoic acid. These carboxylic acids may be used individually or in combination of two or more.

[0056] The curing agent content is preferably 0.1 to 0.6 parts by mass, more preferably 0.15 to 0.5 parts by mass, and even more preferably 0.2 to 0.4 parts by mass, per 100 parts by mass of the refractory granular material. If the curing agent content is above the lower limit, the binder composition (X) can be sufficiently cured. If the curing agent content is below the upper limit, the generation of gas during pouring due to excessive content can be suppressed. In particular, when using a curing agent containing sulfur atoms such as sulfuric acid or organic sulfonic acid, sulfur oxides (SOx) such as sulfur dioxide tend to be generated during pouring, but if the curing agent content is above the lower limit, the amount of sulfur oxides generated can be reduced.

[0057] <Optional ingredients> Optional components to be included in the sand composition include the optional components previously exemplified in the description of the binder composition (X) of the first embodiment of the present invention, as well as anti-blocking agents. Examples of blocking inhibitors include zeolites; and metal salts capable of hydration reactions such as magnesium sulfate, sodium sulfate, and ammonium sulfate. These optional components may be used individually or in combination of two or more.

[0058] <Manufacturing method> The sand composition is obtained by mixing a binder composition (X), a refractory granular material, a hardening agent, and optional components as needed. The sand composition thus obtained is also called "mixed sand (1)". The order in which the components are mixed is not particularly limited; all components may be mixed simultaneously, or, for example, the refractory granular material and the hardening agent may be mixed in advance, and then the binder composition (X) and optional components as needed may be added to the resulting mixture and mixed further. There are no particular limitations on the mixing method, as long as it is a general mixing method; for example, methods using a stirrer can be used.

[0059] In addition to the methods described above, sand compositions can also be manufactured, for example, as follows: Prepare a solution of the curing agent in advance. Suitable solvents include, for example, water; alcohols such as methanol, ethanol, 1-propanol, and 2-propanol; and mixtures thereof. If the curing agent is liquid at room temperature (25°C), it is preferable to dilute it with the aforementioned solvent before use. Next, the refractory granular material is heated. The heating temperature is preferably higher than the boiling point of the solvent, and is usually around 100 to 150°C. Next, a hardening agent solution is added to the heated refractory granular material. When the hardening agent solution is added to the heated refractory granular material, the solvent evaporates and the hardening agent remains on the refractory granular material, resulting in coated sand in which the surface of the refractory granular material is coated with the hardening agent. Next, the coated sand and binder composition (X) are mixed with optional components as needed to obtain a sand composition.

[0060] <Effects and Effects> The sand composition of this embodiment described above contains the binder composition (X) of the first aspect of the present invention described above, and therefore can be used to manufacture a mold with practical strength.

[0061] [Casting mold kit] <Third aspect> Hereinafter, an embodiment of a mold-making kit according to a third aspect of the present invention will be described. The mold-making kit of this embodiment comprises, independently, the binder composition (X) of the first aspect of the present invention described above, a refractory granular material, and a hardening agent. In this invention, "independently possessing" means that each component exists in a state where it is not mixed or in contact with one another. Each component is mixed and in contact for the first time when the mold-making kit is used. The mold-making kit may be, for example, an assembly of containers each containing a binder composition (X), a refractory granular material, and a hardening agent separately.

[0062] Examples of refractory granular materials included in the mold-making kit include the refractory granular materials previously exemplified in the description of the sand composition of the second aspect of the present invention. Examples of hardening agents included in the mold-making kit include the hardening agents previously exemplified in the description of the sand composition of the second embodiment of the present invention.

[0063] If the mold-making kit is an assembly of containers containing each component separately, then one or more of the containers containing the binder composition (X), the container containing the refractory granular material, and the container containing the hardener may contain optional components. Optional components include the optional components previously exemplified in the description of the binder composition (X) of the first embodiment of the present invention, and the blocking inhibitor previously exemplified in the description of the sand composition of the second embodiment of the present invention.

[0064] <Fourth aspect> Hereinafter, an embodiment of a mold-making kit according to the fourth aspect of the present invention will be described. The mold-making kit of this embodiment independently comprises the binder composition (X) of the first aspect of the present invention described above and a refractory granular material containing a hardening agent. The mold-making kit may be, for example, an assembly of containers separately containing a binder composition (X) and a refractory granular material containing a hardening agent. One or more of these containers may contain optional components.

[0065] The refractory granular material containing the hardening agent may be simply a mixture of the refractory granular material and the hardening agent (hereinafter also referred to as "mixed sand (2)"), or it may be coated sand in which the refractory granular material is coated with the hardening agent. That is, the refractory granular material may be contained in a container in the state of mixed sand (2), or in the state of coated sand. Examples of the refractory granular material and hardening agent include those previously exemplified in the description of the sand composition of the second embodiment of the present invention.

[0066] [Method for manufacturing molds] A self-hardening mold molding method can be used as the method for manufacturing the mold. Specifically, the mold is manufactured by bringing the binder composition (X) of the first aspect of the present invention into contact with a refractory granular material and a hardening agent, and hardening the binder composition (X) by the action of the hardening agent. The following are examples of methods for manufacturing a mold.

[0067] <Fifth aspect> Hereinafter, an embodiment of the method for manufacturing a mold according to the fifth aspect of the present invention will be described. In the mold manufacturing method of this embodiment, the sand composition according to the second aspect of the present invention is filled into a mold for mold manufacturing (mold for mold making), and the binder composition (X) contained in the sand composition is hardened to manufacture the mold. There are no particular restrictions on the type of mold used for casting; wooden, resin, or metal molds may be used.

[0068] Alternatively, a mold may be manufactured using a mold-making kit according to the third aspect of the present invention or a mold-making kit according to the fourth aspect of the present invention. When using the mold-making kit according to the third aspect of the present invention, for example, the binder composition (X) according to the first aspect of the present invention, the refractory granular material, and the hardening agent can be taken in the required amounts from the respective containers, mixed together to form a sand composition, and the resulting sand composition can be filled into the mold-making mold. When using the mold-making kit according to the fourth aspect of the present invention, for example, the necessary amounts of the binder composition (X) according to the first aspect of the present invention and the refractory granular material containing a hardening agent can be taken from the respective containers, mixed together to form a sand composition, and the resulting sand composition can be filled into the mold-making mold.

[0069] <Sixth aspect> The following describes one embodiment of the method for manufacturing a mold according to the sixth aspect of the present invention. The mold manufacturing method of this embodiment includes a step (a) of laying a mixture containing a refractory granular material and a hardening agent (hereinafter also referred to as "mixture (M6)") in layers, and a step (b) of injecting and hardening a binder composition (X) of the first embodiment of the present invention into a desired area of ​​the layered mixture (M6) so as to bond the layered mixture (M6) to the target mold, and repeating steps (a) and (b) until the target mold is formed. The mold manufacturing method of this embodiment is a method of manufacturing a mold by three-dimensional additive manufacturing, and the mold obtained by the mold manufacturing method of this embodiment is also referred to as a "three-dimensional additive manufactured object" or "three-dimensional additive manufactured mold". The mixture (M6) may be simply a mixture of refractory granular material and a hardening agent (mixed sand (2)), or it may be coated sand in which the refractory granular material is coated with a hardening agent.

[0070] Processes (a) and (b) are carried out, for example, using a 3D additive manufacturing apparatus employing a printing method, as follows. A three-dimensional additive manufacturing apparatus is preferably equipped with a blade mechanism, a printing nozzle head mechanism, and a build table mechanism. Furthermore, it is preferable to have a control unit that controls the operation of each mechanism using three-dimensional data of the object to be built. The blade mechanism includes a recoater and deposits a mixture (M6) to a predetermined thickness onto the bottom surface of the metal case or onto the upper layer of the molded part which is bonded with a binder composition (X). The printing nozzle head mechanism prints on the stacked mixture (M6) using a binder composition (X), thereby bonding the mixture (M6) and creating the shape layer by layer. The build table mechanism lowers by the distance of one layer after each layer has been built, enabling additive manufacturing at a predetermined thickness.

[0071] First, using a 3D additive manufacturing apparatus employing a printing method, the mixture (M6) is deposited onto the bottom surface of a metal case installed in the 3D additive manufacturing apparatus by a blade mechanism with a recoater (step (a)). Next, the printing nozzle head is scanned by the printing nozzle head mechanism based on data obtained by 3D CAD design of the shape of the target 3D additive manufacturing mold, and the first binder composition (X) of the present invention is printed (injected) (step (b)). The bottom surface of the metal case serves as a build table and can move up and down. After printing the binder composition (X), the bottom surface (build table) of the metal case is lowered by one layer, and the mixture (M6) is laminated in the same manner as before (step (a)), and the binder composition (X) is printed on top of it (step (b)). These lamination and printing operations are repeated until the target 3D additive manufacturing mold is formed. The thickness of each layer is preferably 100 to 500 μm, and more preferably 200 to 300 μm.

[0072] The amount of binder composition (X) applied when printing is preferably 0.5 to 3.0 parts by mass, more preferably 0.8 to 2.0 parts by mass, and even more preferably 1.0 to 1.5 parts by mass, when the mass of the refractory granular material in one layer of mixture (M6) in the printing area is 100 parts by mass.

[0073] <Effects and Effects> According to the mold manufacturing method of the fifth and sixth aspects of the present invention described above, since the binder composition (X) of the first aspect of the present invention is used, a mold with practical strength can be manufactured. [Examples]

[0074] Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. The materials used in each example are shown below. Also, various measurement methods are as follows.

[0075] [Materials] <Production of furan resin mixture (M2-1)> Into a four-necked flask equipped with a thermometer, a cooler and a stirrer, 669 parts by mass of furfuryl alcohol, 173 parts by mass of urea, 94 parts by mass of 92% paraformaldehyde, and 1.1 parts by mass of a 15% aqueous sodium hydroxide solution were charged and reacted at 80 °C for 1 hour. Then, 2.8 parts by mass of 10% hydrochloric acid was added and the reaction was further carried out for 3 hours (condensation reaction). Then, 2.0 parts by mass of a 15% aqueous sodium hydroxide solution and 17 parts by mass of urea were added and the reaction was further carried out for 30 minutes to obtain a reaction mixture. To the obtained reaction mixture, 20 parts by mass of resorcinol as a formaldehyde scavenger, 2.0 parts by mass of N-β(aminoethyl)γ-aminopropylmethyldimethoxysilane as a silane coupling agent, and 20 parts by mass of water were added to obtain a furan resin mixture (M2-1) containing a furan resin which is a condensate of furfuryl alcohol, urea and aldehydes, furfuryl alcohol, a silane coupling agent, and water. The content of the furan resin with respect to the total mass of the furan resin mixture (M2-1) was 27.1% by mass, the content of furfuryl alcohol was 52.5% by mass, the content of water was 18.5% by mass, the content of the silane coupling agent was 0.2% by mass, and the content of optional components other than the silane coupling agent (other optional components) was 1.7% by mass.

[0076] <HMF mixture (M4-1)> As the HMF mixture (M4-1), a mixture containing 84% by mass of 5-hydroxymethylfurfural and 8.5% by mass of water was used.

[0077] <Refractory granular material> As the refractory granular material, silica sand (manufactured by Mitsubishi Corporation Building Materials Co., Ltd., trade name "Freemantle new sand") was used.

[0078] <Hardener> The following substances were used as hardening agents. • GH-20: An acid catalyst containing sulfuric acid and xylene sulfonic acid (manufactured by Gun-ei Chemical Industry Co., Ltd., product name "GH-20"). • LH-100: An acid catalyst containing metaxylenesulfonic acid and lactic acid (manufactured by Gun-ei Chemical Industry Co., Ltd., product name "LH-100").

[0079] [Measurement and Evaluation Methods] <Measuring the flash point> The flash point of the binder composition (X) was measured using a flash point meter (manufactured by Yoshida Scientific Instruments Co., Ltd.) with a Cleveland open-type flash point test, in accordance with the method for determining flash point specified in JIS K 2265-4:2007.

[0080] <Measurement of pot life> Pot life was measured according to the measurement method described in JACT Test Method HM-2.

[0081] <Measurement of compressive strength> The compressive strength of the test specimens was measured using a benchtop pressure resistance tester (manufactured by Takachiho Machinery Co., Ltd.) in accordance with the test method for foundry sand specified in JIS Z 2601:1993.

[0082] [Example 1] <Manufacturing of binder composition (X)> A binder composition (X) was obtained by mixing 90 parts by mass of a furan resin mixture (M2-1) and 10 parts by mass of an HMF mixture (M4-1). Table 1 shows the content of furfuryl alcohol, furan resin, 5-hydroxymethylfurfural (HMF), water, and silane coupling agent, as well as other optional components (other optional components), relative to the total mass of the binder composition (X). Furthermore, the flash point of the obtained binder composition (X) was measured. The results are shown in Table 1.

[0083] <Manufacturing of sand composition> GH-20 (92 parts by mass) and LH-100 (8 parts by mass) were mixed to give the sand composition a pot life of 11 minutes, and the resulting mixture was used as a hardening agent. 100 parts by mass of refractory granular material, 0.8 parts by mass of binder composition (X) in its original form, and 0.32 parts by mass of hardening agent were placed in a Shinagawa-type universal mixer (manufactured by Shinagawa Kogyosho Co., Ltd., product name "MIXER") and mixed for 60 seconds to obtain a sand composition.

[0084] <Manufacturing of test specimens> The obtained sand composition was immediately filled into a wooden mold with 15 cylindrical molds, each 50 mm in diameter and 50 mm deep, under conditions of 20°C and 50% humidity to harden the binder composition (X). After 0.5 hours from the start of mixing, three test specimens were removed from the wooden mold, and the compressive strength of each specimen was measured and the average value was calculated. The results are shown in Table 1. Similarly, three test pieces were removed from the wooden mold at 1 hour, 3 hours, 5 hours, and 24 hours after the start of mixing, and the compressive strength of each test piece was measured and the average value was calculated. The results are shown in Table 2.

[0085] [Example 2] <Manufacturing of binder composition (X)> A binder composition (X) was obtained by mixing 80 parts by mass of a furan resin mixture (M2-1) and 20 parts by mass of an HMF mixture (M4-1). Table 1 shows the content of furfuryl alcohol, furan resin, 5-hydroxymethylfurfural, water, and silane coupling agent, as well as other optional components (other optional components), relative to the total mass of the binder composition (X). Furthermore, the flash point of the obtained binder composition (X) was measured. The results are shown in Table 1.

[0086] <Manufacturing of sand composition and test specimens> GH-20 (80 parts by mass) and LH-100 (20 parts by mass) were mixed to give the sand composition a pot life of 11 minutes, and the resulting mixture was used as a hardening agent. A sand composition was prepared in the same manner as in Example 1, except that the previously obtained binder composition (X) and hardening agent were used. Except for using the sand composition obtained in this manner, test specimens were prepared in the same manner as in Example 1, and the compressive strength of each test specimen was measured. The results are shown in Table 2.

[0087] [Comparative Example 1] <Manufacturing of test specimens> A sand composition was prepared in the same manner as in Example 1, except that a furan resin mixture (M2-1) was used as the binder composition (X) and GH-20 was used as the curing agent. The flash point of the furan resin mixture (M2-1) used as the binder composition (X) was also measured. The results are shown in Table 1. Except for using the sand composition obtained in this manner, test specimens were prepared in the same manner as in Example 1, and the compressive strength of each test specimen was measured. The results are shown in Table 2.

[0088] [Comparative Example 2] <Manufacturing of binder composition (X)> A binder composition (X) was obtained by mixing 75 parts by mass of a furan resin mixture (M2-1) with 25 parts by mass of an HMF mixture (M4-1). Table 1 shows the content of furfuryl alcohol, furan resin, 5-hydroxymethylfurfural, water, and silane coupling agent, as well as optional components other than the silane coupling agent, relative to the total mass of the binder composition (X). Furthermore, the flash point of the obtained binder composition (X) was measured. The results are shown in Table 1.

[0089] <Manufacturing of sand composition and test specimens> GH-20 (68 parts by mass) and LH-100 (32 parts by mass) were mixed so that the working time of the sand composition would be 11 minutes, and the resulting mixture was used as a hardening agent. A sand composition was prepared in the same manner as in Example 1, except that the previously obtained binder composition (X) and hardening agent were used. Except for using the sand composition obtained in this manner, test specimens were prepared in the same manner as in Example 1, and the compressive strength of each test specimen was measured. The results are shown in Table 2.

[0090] [Comparative Example 3] <Manufacturing of binder composition (X)> A binder composition (X) was obtained by mixing 89.3 parts by mass of a furan resin mixture (M2-1) with 10.7 parts by mass of furfuryl alcohol. Table 1 shows the content of furfuryl alcohol, furan resin, 5-hydroxymethylfurfural, water, and silane coupling agent, as well as other optional components (other optional components), relative to the total mass of the binder composition (X). Furthermore, the flash point of the obtained binder composition (X) was measured. The results are shown in Table 1.

[0091] <Manufacturing of sand composition and test specimens> GH-20 (95 parts by mass) and LH-100 (5 parts by mass) were mixed to give the sand composition a pot life of 11 minutes, and the resulting mixture was used as a hardening agent. A sand composition was prepared in the same manner as in Example 1, except that the previously obtained binder composition (X) and hardening agent were used. Except for using the sand composition obtained in this manner, test specimens were prepared in the same manner as in Example 1, and the compressive strength of each test specimen was measured. The results are shown in Table 2.

[0092] [Table 1]

[0093] [Table 2]

[0094] As is clear from Tables 1 and 2, the binder compositions (X) obtained in Examples 1 and 2 do not have a flash point and can therefore be treated as non-hazardous materials under the Fire Service Act (i.e., they do not fall under the category of hazardous materials (Class 4, Third Petroleum) as defined by the Fire Service Act). Furthermore, the test specimens produced using these binder compositions (X) exhibited high compressive strength. On the other hand, Comparative Example 1's binder composition (X), which did not contain 5-hydroxymethylfurfural (component (C)) and had a water content of 18.5% by mass (component (D)), did not have a flash point. However, the test specimens produced using this binder composition (X) had lower compressive strength compared to the test specimens obtained in Examples 1 and 2. Comparative Example 2's binder composition (X), which has a water content of 15.7% by mass, had a flash point and therefore falls under the category of hazardous materials (Class 4, Third Petroleum) as defined by the Fire Service Act. Comparative Example 3, the binder composition (X), which does not contain 5-hydroxymethylfurfural and has a water content of 16.5% by mass, had a flash point and therefore falls under the category of hazardous materials (Class 4, Third Petroleum) as defined by the Fire Service Act.

Claims

1. (A) Ingredients: Furfuryl alcohol and (B) Components: Furan resin, or a condensate of urea and aldehydes, (C) Ingredients: 5-hydroxymethylfurfural and (D) Ingredients: Water and A binder composition containing, A binder composition wherein the content of component (C) is 0.1 to 40% by mass and the content of component (D) is 16.0 to 18.7% by mass, based on the total mass of the binder composition.

2. A sand composition comprising the binder composition described in claim 1, a fire-resistant granular material, and a hardening agent.

3. A mold-making kit comprising, independently, the binder composition described in claim 1, a refractory granular material, and a hardening agent.

4. A mold-making kit comprising, independently, the binder composition described in claim 1 and a refractory granular material containing a hardening agent.

5. A method for manufacturing a mold, comprising filling a mold for manufacturing a mold with the sand composition described in claim 2, and hardening the binder composition contained in the sand composition.

6. A method for manufacturing a mold by three-dimensional additive manufacturing, (a) A step of laying a mixture containing fire-resistant granular material and a hardening agent in layers, The step (b) involves injecting the binder composition according to claim 1 into a desired region of the layered mixture, A method for manufacturing a mold, comprising repeating the above steps (a) and (b) until the desired mold is formed.

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