Method for producing a binder resin for mold molding

Abstract

The present invention is a method for producing a mold-making binder resin containing a bis-hydroxymethyl furan and a furan resin, and has a step A of reacting furfuryl alcohol with formaldehyde in the presence of one or more catalysts a selected from phosphoric acid and boric acid and one or more neutralizing salts a selected from neutralizing salts of phosphoric acid and boric acid, and in the step A, the amount of the catalyst a is 0.0002 mol or more and 0.01 mol or less per 1 mol of the furfuryl alcohol, and the amount of the neutralizing salt a is 0.003 mol or more in terms of acid per 1 mol of the furfuryl alcohol. According to the present invention, a method for producing a mold-making binder resin having a fast reaction speed, a low viscosity, a small content of monomeric furfuryl alcohol, and a large content of bis-hydroxymethyl furan can be provided.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a binder resin for casting molding. Background Technology

[0002] Generally, acid-curing molds are manufactured by adding a mold-forming binder composition containing an acid-curing resin and a curing agent composition containing sulfonic acid, sulfuric acid, phosphoric acid, etc., to refractory particles such as silica sand. After mixing these, the resulting mixed sand is filled into a master mold such as a wooden mold, and the acid-curing resin is then cured. Acid-curing resins used include furan resins, phenolic resins, etc. Furan resins used include furan-methanol-urea-formaldehyde resin, furan-methanol-formaldehyde resin, furan-methanol-phenol-formaldehyde resin, and other known modified furan resins. This mold-making method allows for highly flexible molding operations. Furthermore, the molds have excellent thermal properties, enabling the production of high-quality castings. Therefore, it is widely used in casting mechanical parts, construction machinery parts, and automotive parts.

[0003] In mold manufacturing, one important factor is the improvement of the working environment during mold manufacturing (resin curing), especially in order to reduce the volatilization of furanol during mold manufacturing, and to reduce the amount of monomeric furanol in furan resin.

[0004] For example, Japanese Patent Publication No. 2014-501175 discloses a method that reduces the release of furan methanol and formaldehyde during mixing and molding by using a binder composition with a low content of monomeric furan methanol.

[0005] In addition, Japanese Patent Application Publication No. 56-61420 discloses a method for manufacturing a phenol-furan methanol-formaldehyde resin for molding with a low content of monomeric furan methanol, which introduces a furan methanol skeleton into the resin structure in a high proportion through a full reaction.

[0006] Furthermore, Japanese Patent Application Publication No. 2013-151019 discloses a binder composition that uses 5-hydroxymethylfurfural and 2,5-dihydroxymethylfuran instead of furanol to shorten the demolding time under the same service life, thereby improving mold productivity and increasing curing speed and mold strength. Summary of the Invention

[0007] This invention relates to a method for manufacturing a molding binder resin. The method comprises a molding binder resin containing furanol, dihydroxymethylfuran, and furan resin. Step A involves reacting furanol with formaldehyde in the presence of one or more catalysts selected from phosphoric acid and boric acid, and one or more neutralizing salts selected from phosphoric acid and boric acid. In step A, the amount of catalyst a relative to 1 mole of furanol is 0.0002 mol or more and 0.01 mol or less, and the amount of neutralizing salt a relative to 1 mole of furanol is 0.003 mol or more (converted to acid).

[0008] In addition, the present invention is a molding binder composition containing furanol (component A), bis(hydroxymethyl)furan (component B), furan resin (component C) and water (component D), and satisfies the following conditions (1) to (4).

[0009] Condition (1): The content of component A in the above-mentioned mold molding binder composition is 30% by mass or less;

[0010] Condition (2): The content of component B in the above-mentioned mold molding binder composition is 7% by mass or more;

[0011] Condition (3): The content of component D in the above-mentioned mold molding binder composition is 25% by mass or less;

[0012] Condition (4): In 100g of the above-mentioned binder composition for molding molds, the content of one or more catalysts selected from phosphoric acid and boric acid is 0.01g or more and 0.50g or less, and the content of one or more neutral salts selected from phosphoric acid and boric acid, converted into acid, is 0.13g or more.

[0013] In addition, the present invention is a composition for molding a mold, which contains the above-mentioned adhesive composition for molding a mold and a curing agent composition containing a curing agent for curing the adhesive composition for molding a mold.

[0014] In addition, the present invention is a mold composition comprising refractory particles, the above-mentioned mold molding adhesive composition, and a curing agent composition comprising a curing agent for curing the mold molding adhesive composition.

[0015] In addition, the present invention is a method for manufacturing a mold, comprising: a mixing step, wherein refractory particles, the above-mentioned mold-forming adhesive composition, and a curing agent composition comprising a curing agent for curing the mold-forming adhesive composition are mixed to obtain a mold composition; and a curing step, wherein the above-mentioned mold composition is filled into a mold frame and the mold composition is cured. Detailed Implementation

[0016] Regarding the binder compositions with low content of monomeric furanol in the past, there is room for improvement due to insufficient mold strength. Additionally, the addition of dimethylolfuran to improve mold strength has been considered, but this is not economically feasible.

[0017] This invention provides a method for manufacturing a molding binder resin with fast reaction speed, low content of monomeric furanol, high content of dimethylolfuran, and low viscosity. Furthermore, this invention provides a molding binder composition, a molding composition, and a molding mold composition that have low content of monomeric furanol, high content of dimethylolfuran, low viscosity, and can improve mold strength, as well as a method for manufacturing a mold.

[0018] This invention relates to a method for manufacturing a molding binder resin. The method comprises a molding binder resin containing furanol, dihydroxymethylfuran, and furan resin. Step A involves reacting furanol with formaldehyde in the presence of one or more catalysts selected from phosphoric acid and boric acid, and one or more neutralizing salts selected from phosphoric acid and boric acid. In step A, the amount of catalyst a relative to 1 mole of furanol is 0.0002 mol or more and 0.01 mol or less, and the amount of neutralizing salt a relative to 1 mole of furanol is 0.003 mol or more (converted to acid).

[0019] In addition, the present invention is a molding binder composition containing furanol (component A), bis(hydroxymethyl)furan (component B), furan resin (component C) and water (component D), and satisfies the following conditions (1) to (4).

[0020] Condition (1): The content of component A in the above-mentioned mold molding binder composition is 30% by mass or less;

[0021] Condition (2): The content of component B in the above-mentioned mold molding binder composition is 7% by mass or more;

[0022] Condition (3): The content of component D in the above-mentioned mold molding binder composition is 25% by mass or less;

[0023] Condition (4): In 100g of the above-mentioned binder composition for molding molds, the content of one or more catalysts selected from phosphoric acid and boric acid is 0.01g or more and 0.50g or less, and the content of one or more neutral salts selected from phosphoric acid and boric acid, converted into acid, is 0.13g or more.

[0024] In addition, the present invention is a composition for molding a mold, which contains the above-mentioned adhesive composition for molding a mold and a curing agent composition containing a curing agent for curing the adhesive composition for molding a mold.

[0025] In addition, the present invention is a mold composition comprising refractory particles, the above-mentioned mold molding adhesive composition, and a curing agent composition comprising a curing agent for curing the mold molding adhesive composition.

[0026] In addition, the present invention is a method for manufacturing a mold, comprising: a mixing step, wherein refractory particles, the above-mentioned mold-forming adhesive composition, and a curing agent composition comprising a curing agent for curing the mold-forming adhesive composition are mixed to obtain a mold composition; and a curing step, wherein the above-mentioned mold composition is filled into a mold frame and the mold composition is cured.

[0027] According to the present invention, a method for manufacturing a molding binder resin that has a fast reaction rate, low content of monomeric furanol, high content of dimethylolfuran, and low viscosity can be provided. Furthermore, the present invention can provide a molding binder composition, a molding composition, and a molding mold composition that have a low content of monomeric furanol, high content of dimethylolfuran, low viscosity, and can improve mold strength, as well as a method for manufacturing a mold.

[0028] Hereinafter, one embodiment of the present invention will be described.

[0029] <Method for manufacturing adhesive resin for casting>

[0030] Regarding the method for manufacturing the molding binder resin (hereinafter also simply referred to as binder resin) of this embodiment,

[0031] It is a method for manufacturing a molding binder resin containing furanol, dihydroxymethylfuran (hereinafter also known as BHMF), and furan resin.

[0032] The method includes step A, which involves reacting furan-methanol with formaldehyde in the presence of one or more catalysts selected from phosphoric acid and boric acid, and one or more neutralizing salts selected from phosphoric acid and boric acid.

[0033] In step A above, the amount of catalyst a used is 0.0002 moles or more and 0.01 moles or less relative to 1 mole of furan-methanol, and the amount of neutralizing salt a used is 0.003 moles or more of acid relative to 1 mole of furan-methanol.

[0034] According to the method for manufacturing the adhesive resin of this embodiment, an adhesive resin with fast reaction rate, low content of monomeric furanyl alcohol, high content of BHMF, and low viscosity can be produced. The reason why the above-described method for manufacturing the adhesive composition achieves this effect is not yet certain, but the following can be considered.

[0035] If the amount of catalyst a, which serves as the catalyst for manufacturing the binder resin, is too small, the reaction of furanol (component A) becomes extremely slow, and the formation of BHMF (component B) decreases. On the other hand, if the amount of catalyst a is too large, the reaction of furanol becomes faster, but it is believed that the condensation of BHMF is more likely to occur, leading to its disappearance. It is believed that by containing a certain amount or more of the neutralizing salt a, the equilibrium of the dissociation of phosphoric acid and boric acid, which serve as catalyst a, is adjusted to the direction of inhibiting dissociation. The reaction of furanol becomes moderately faster, BHMF is more easily formed, and the reaction of BHMF is moderately inhibited, thus obtaining a binder resin with a low furanol content and a high BHMF content. Since the reactivity of BHMF is higher than that of furanol and furan resin (component C), it is believed that the binder composition of this embodiment, despite having a low furanol content, has a high BHMF (component B) content, resulting in low viscosity and improved molding strength of the binder.

[0036] [Process A]

[0037] The above-mentioned step A is a step in which furan-methanol reacts with formaldehyde in the presence of one or more catalysts selected from phosphoric acid and boric acid and one or more neutral salts selected from phosphoric acid and boric acid.

[0038] [catalyst a]

[0039] The catalyst a described above is selected from one or more catalysts chosen from phosphoric acid and boric acid. Regarding the catalyst a described above, from the viewpoint of increasing the reaction rate, it is preferable that it contains phosphoric acid, and more preferably phosphoric acid.

[0040] In step A above, regarding the amount of catalyst a, from the viewpoint of increasing the reaction rate of furanol and formaldehyde, it is 0.0002 mol or more, preferably 0.0004 mol or more, more preferably 0.0006 mol or more, further preferably 0.0008 mol or more, and even more preferably 0.0009 mol or more, relative to 1 mol of furanol. In step A above, regarding the amount of catalyst a, from the viewpoint of increasing the BHMF content in the binder resin, it is 0.01 mol or less, preferably 0.008 mol or less, more preferably 0.005 mol or less, further preferably 0.003 mol or less, and even more preferably 0.002 mol or less, relative to 1 mol of furanol.

[0041] [Neutralizing Salt a]

[0042] The neutralizing salt a mentioned above is one or more neutralizing salts selected from phosphoric acid and boric acid. Regarding the neutralizing salt a mentioned above, from the viewpoint of increasing the reaction rate, a neutralizing salt containing phosphoric acid is preferred, and a neutralizing salt containing phosphoric acid is more preferred.

[0043] In step A above, regarding the amount of neutralizing salt a, from the viewpoint of increasing the BHMF content in the adhesive resin and increasing the reaction rate of furanyl methanol and formaldehyde, the amount of acid equivalent to 1 mole of furanyl methanol is 0.003 mol or more, preferably 0.004 mol or more, more preferably 0.005 mol or more, even more preferably 0.006 mol or more, even more preferably 0.009 mol or more, even more preferably 0.010 mol or more, and even more preferably 0.014 mol or more. In step A above, regarding the amount of neutralizing salt a, from the viewpoint of increasing the BHMF content in the adhesive resin, the amount of acid equivalent to 1 mole of furanyl methanol is preferably 0.15 mol or less, more preferably 0.12 mol or less, even more preferably 0.10 mol or less, even more preferably 0.04 mol or less, and even more preferably 0.03 mol or less.

[0044] The neutralizing salt a described above may be one or more selected from alkali metal salts and amine salts. Examples of alkali metal salts include one or more selected from sodium and potassium salts. Examples of amine salts include amine salts having alkyl groups. The alkyl group may optionally have a hydroxyl group; from the viewpoint of increasing the reaction rate of furan-methanol with formaldehyde and increasing the BHMF content in the adhesive resin, a hydroxyl group is preferred.

[0045] When the amine salt has an alkyl group, the number of carbon atoms in the alkyl group is preferably 2 or more, more preferably 3, from the viewpoint of increasing the BHMF content in the binder resin. When the amine salt has an alkyl group, the number of carbon atoms in the alkyl group is preferably 10 or less, more preferably 8 or less, further preferably 6 or less, even more preferably 4 or less, and even more preferably 3, from the viewpoint of solubility with furanyl alcohol and increasing the reaction rate of furanyl alcohol with formaldehyde.

[0046] Regarding the aforementioned amine salts, tertiary amines are preferred from the viewpoint of low reactivity with formaldehyde. Examples of such tertiary amines include triethanolamine, tripropylamine, triisopropanolamine, tributylamine, trihexylamine, and trioctylamine.

[0047] Regarding the aforementioned neutralizing salt a, from the viewpoints of increasing the reaction rate of furanyl methanol with formaldehyde and increasing the BHMF content in the adhesive resin, an amine salt is preferred, more preferably an amine salt having an alkyl group having 2 or more but less than 10 carbon atoms, further preferably a tertiary amine salt having an alkyl group having 2 or more but less than 10 carbon atoms, and even more preferably a tertiary amine salt having a hydroxyl group having 2 or more but less than 10 carbon atoms. Furthermore, regarding neutralizing salt a, from the same viewpoint, it is preferably selected from one or more of triethanolamine, tripropylamine, triisopropanolamine, tributylamine, trihexylamine, and trioctylamine, more preferably from one or more of triethanolamine and triisopropanolamine.

[0048] The amounts of the catalyst a and the neutralizing salt a relative to 1 mole of furan-methanol can be adjusted by the amount of one or more selected from phosphoric acid and boric acid, and the amount of one or more selected from alkali metals and amines.

[0049] Regarding the degree of neutralization of catalyst a [neutralized salt a / (catalyst a + neutralized salt a)], from the viewpoint of increasing the content of BHMF in the binder resin and increasing the reaction rate of furanol methanol and formaldehyde, it is preferably 25% or more, more preferably 30% or more, further preferably 50% or more, even more preferably 85% or more, even more preferably 90% or more, even more preferably 93% or more. From the same viewpoint, it is preferably less than 100%, more preferably 97% or less, and even more preferably 96% or less.

[0050] [Furan resin]

[0051] The aforementioned furan resin is obtained by polymerizing a monomer composition containing furanol, and is not particularly limited as long as it can be used as a binder for molding. This furan resin may be a resin containing only nitrogen atoms, a resin without nitrogen atoms, or a mixture of a nitrogen-containing resin and a nitrogen-free resin. Examples of nitrogen-containing furan resins include one or more selected from the group consisting of: condensates of furanol with urea and aldehydes (urea-modified furan resin), condensates of furanol with melamine and aldehydes, and condensates of furanol with ethylene urea and aldehydes. Examples of nitrogen-free furan resins include one or more selected from the group consisting of: condensates of furanol with aldehydes, and condensates of furanol with phenols and aldehydes. It should be noted that furanol is not included in the furan resin in this specification.

[0052] Regarding the aforementioned furan resin, from the viewpoint of having a low content of monomeric furanol, a high content of BHMF, low viscosity, and improved mold strength, it is preferable to contain one or more substances selected from the group consisting of: furanol condensates with urea and aldehydes (urea-modified furan resin), furanol condensates with melamine and aldehydes, furanol condensates with ethylene urea and aldehydes, furanol condensates with aldehydes, furanol condensates with phenols and aldehydes, and co-condensates selected from two or more substances selected from urea-modified furan resin, furanol condensates with melamine and aldehydes, furanol condensates with ethylene urea and aldehydes, furanol condensates with aldehydes, and furanol condensates with phenols and aldehydes.

[0053] More preferably, it contains one or more substances selected from the group consisting of: urea-modified furan resin, condensate of furan methanol and aldehydes, and two or more co-condensates selected from urea-modified furan resin and condensate of furan methanol and aldehydes.

[0054] Regarding the total content of the furan resin selected from urea-modified furan resin, furan methanol and aldehyde condensates, and one or more co-condensates selected from urea-modified furan resin and furan methanol and aldehyde condensates, from the viewpoint of having a low content of monomeric furan methanol, a high content of BHMF, low viscosity, and improved mold strength, it is preferably 90% by mass or more, more preferably 95% by mass or more, further preferably 98% by mass or more, further preferably substantially 100% by mass, and even more preferably 100% by mass. It should be noted that, in this specification, "substantially" means an amount that may also contain impurities.

[0055] Examples of aldehydes mentioned above include formaldehyde, acetaldehyde, glyoxal, furfural, terephthalaldehyde, and hydroxymethylfurfural, and one or more of these can be used appropriately. From the viewpoint of improving mold strength, formaldehyde is preferred, and from the viewpoint of reducing formaldehyde generation during molding, furfural, terephthalaldehyde, and hydroxymethylfurfural are preferred.

[0056] From the viewpoint of obtaining a mold-forming binder resin with fast reaction rate, low content of monomeric furanyl alcohol, high content of BHMF, and low viscosity, and from the viewpoint of obtaining a mold-forming binder composition with low content of monomeric furanyl alcohol, high content of BHMF, low viscosity, and improved mold strength, the above-mentioned aldehydes contain formaldehyde. Regarding the formaldehyde content in the aldehydes, from the same viewpoint, it is preferably 80% by mass or more, more preferably 90% by mass or more, further preferably 98% by mass or more, and even more preferably substantially 100% by mass. Here, "substantially 100% by mass" means that it may contain unintentionally contained components. Examples of unintentionally contained components include, for example, unavoidable impurities.

[0057] Examples of the aforementioned phenols include phenol, cresol, resorcinol, bisphenol A, bisphenol C, bisphenol E, and bisphenol F, and one or more of these may be used.

[0058] In step A above, a furan resin is obtained by using a specific amount of the catalyst a and the neutralizing salt a, and reacting furan methanol with aldehydes, phenols as needed, ureas such as urea or ethylene urea, and melamine. The reaction temperature and other conditions can be appropriately adjusted according to the target furan resin. As an example, reaction conditions are shown for the case where the target furan resin is "selected from one or more of the group consisting of furan methanol condensates with aldehydes, or furan methanol, phenols, and aldehydes (hereinafter also referred to as nitrogen-free furan resin)," and for the case where the target furan resin is "selected from one or more of the group consisting of urea-modified furan resin, furan methanol condensates with melamine and aldehydes, and furan methanol condensates with ethylene urea and aldehydes (hereinafter also referred to as nitrogen-containing furan resin)."

[0059] [Example of reaction conditions for furan resins that do not contain nitrogen atoms]

[0060] (Reaction temperature)

[0061] Regarding the reaction temperature of step A in obtaining the aforementioned nitrogen-free furan resin, from the viewpoint of improving productivity, it is preferably 80°C or higher, more preferably 90°C or higher. Regarding the reaction temperature of step A in obtaining the aforementioned nitrogen-free furan resin, from the viewpoint of suppressing the condensation between furan and methanol and increasing the BHMF content, it is preferably 125°C or lower, more preferably 115°C or lower, and even more preferably 110°C or lower.

[0062] (pH value before the reaction begins)

[0063] Regarding the pH value of the reaction solution before the start of the reaction in step A above, from the viewpoint of increasing the BHMF content in the adhesive resin, it is preferably 2 or more, more preferably 2.5 or more, further preferably 3.3 or more, and even more preferably 3.7 or more. Regarding the pH value of the reaction solution before the start of the reaction in step A above, from the viewpoint of increasing the reaction rate of furanyl alcohol and formaldehyde, it is preferably 5.5 or less, more preferably 5.0 or less, further preferably 4.5 or less, and even more preferably 4.1 or less. It should be noted that the pH value of the reaction solution before the start of the reaction in step A above can be measured according to the method described in the examples.

[0064] (Reaction Time)

[0065] Regarding the reaction time of step A in obtaining the aforementioned nitrogen-free furan resin, from the viewpoint of reducing the content of furan-methanol and suppressing the condensation between furan-methanol molecules and increasing the content of BHMF, it is preferably 200 minutes or more, more preferably 250 minutes or more, and even more preferably 280 minutes or more. Regarding the reaction time of step A in obtaining the aforementioned nitrogen-free furan resin, from the viewpoint of improving productivity, it is preferably 750 minutes, more preferably 620 minutes or less, even more preferably 600 minutes or less, even more preferably 570 minutes or less, even more preferably 520 minutes or less, and even more preferably 490 minutes or less.

[0066] (Reaction pressure)

[0067] Regarding the reaction pressure in step A above, in the case of obtaining the nitrogen-free furan resin described above, both reduced pressure and atmospheric pressure are acceptable. From the viewpoint of shortening the reaction time, reduced pressure is preferred.

[0068] [Example of reaction conditions for furan resins containing nitrogen atoms]

[0069] In obtaining a furan resin containing nitrogen atoms, from the viewpoint of reducing the content of furan methanol and free aldehydes in the obtained resin, it is preferable to first react furan methanol with aldehydes, and then react it with ureas and / or melamine, etc. That is, in obtaining a furan resin containing nitrogen atoms, from the viewpoint of reducing the content of furan methanol and free aldehydes in the obtained resin, the above-mentioned step A preferably includes a step A1 in which furan methanol reacts with aldehydes, and a step A2 in which the reaction intermediate obtained in the above-mentioned step A1 reacts with ureas and / or melamine, etc.

[0070] (Process A1)

[0071] (Reaction temperature)

[0072] Regarding the reaction temperature of step A1 in obtaining the aforementioned furan resin containing nitrogen atoms, from the viewpoint of improving productivity, it is preferably 80°C or higher, more preferably 90°C or higher. Regarding the reaction temperature of step A1 in obtaining the aforementioned furan resin containing nitrogen atoms, from the viewpoint of suppressing the condensation between furan and methanol and increasing the BHMF content, it is preferably 125°C or lower, more preferably 115°C or lower, and even more preferably 110°C or lower.

[0073] (Reaction Time)

[0074] Regarding the reaction time of step A1 in obtaining the aforementioned furan resin containing nitrogen atoms, from the viewpoint of reducing the content of furan-methanol and inhibiting the condensation between furan-methanol molecules and increasing the content of BHMF, it is preferably 200 minutes or more, more preferably 250 minutes or more, and even more preferably 280 minutes or more. Regarding the reaction time of step A1 in obtaining the aforementioned furan resin containing nitrogen atoms, from the viewpoint of improving productivity, it is preferably 750 minutes or less, more preferably 620 minutes or less, even more preferably 600 minutes or less, even more preferably 570 minutes or less, even more preferably 520 minutes or less, and even more preferably 490 minutes or less.

[0075] (Reaction pressure)

[0076] Regarding the reaction pressure in step A1 of obtaining the aforementioned furan resin containing nitrogen atoms, both reduced pressure and atmospheric pressure are acceptable. From the viewpoint of shortening the reaction time, reduced pressure is preferred.

[0077] (Process A2)

[0078] (Reaction temperature)

[0079] Regarding the reaction temperature of step A2 in obtaining the aforementioned furan resin containing nitrogen atoms, from the viewpoint of improving productivity and reducing the content of free furan methanol or aldehydes, it is preferably 80°C or higher, more preferably 90°C or higher, and even more preferably 95°C or higher. Regarding the reaction temperature of step A2 in obtaining the aforementioned furan resin containing nitrogen atoms, from the viewpoint of preventing a decrease in BHMF content and suppressing viscosity increase, it is preferably 135°C or lower, more preferably 125°C or lower, and even more preferably 115°C or lower.

[0080] (Reaction Time)

[0081] Regarding the reaction time of step A2 in the case of obtaining the above-mentioned furan resin containing nitrogen atoms, from the viewpoint of reducing the content of free furan methanol or aldehydes, it is preferably 30 minutes or more. Regarding the reaction time of step A2 in the case of obtaining the above-mentioned furan resin containing nitrogen atoms, from the viewpoint of improving productivity, preventing the reduction of BHMF content, and suppressing viscosity increase, it is preferably 3 hours or less, more preferably 2 hours or less.

[0082] (Reaction pressure)

[0083] Regarding the reaction pressure of step A2 in the case of obtaining the aforementioned furan resin containing nitrogen atoms, both reduced pressure and atmospheric pressure are acceptable. From the viewpoint of shortening the reaction time, reduced pressure is preferred.

[0084] In obtaining the above-mentioned furan resin containing nitrogen atoms, a step A3 for reducing the content of free aldehydes in the above-mentioned adhesive resin may also be provided after the above-mentioned step A2.

[0085] (Process A3)

[0086] (Reaction temperature)

[0087] Regarding the reaction temperature of step A3 above, from the viewpoints of improving productivity and reducing the content of free aldehydes, it is preferably 50°C or higher, more preferably 60°C or higher. Regarding the reaction temperature of step A3 above, from the viewpoints of preventing a decrease in the content of BHMF and preventing an increase in viscosity, it is preferably 80°C or lower.

[0088] (Reaction Time)

[0089] Regarding the reaction time of step A3 above, from the viewpoint of reducing the content of free aldehydes, it is preferably 10 minutes or more. Regarding the reaction time of step A3 above, from the viewpoint of improving productivity, it is preferably 1 hour or more, more preferably 40 minutes or more, and even more preferably 30 minutes or more.

[0090] (Reaction pressure)

[0091] Regarding the reaction pressure in step A3 above, both reduced pressure and atmospheric pressure are acceptable. However, from the viewpoint of shortening the reaction time, reduced pressure is preferred.

[0092] Regarding the content of furanyl alcohol in the aforementioned adhesive resin, from the viewpoint of improving mold strength, it is preferably 10% by mass or more, more preferably 15% by mass or more. Regarding the content of furanyl alcohol in the aforementioned adhesive resin, from the viewpoint of improving the working environment, it is preferably 35% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less. It should be noted that the content of furanyl alcohol can be determined according to the method described in the examples.

[0093] Regarding the BHMF content in the aforementioned adhesive resin, from the viewpoint of improving mold strength, it is preferably 8% by mass or more, more preferably 10% by mass or more, further preferably 15% by mass or more, and even more preferably 20% by mass or more. Regarding the BHMF content in the aforementioned adhesive resin, from the viewpoint of suppressing BHMF precipitation, it is preferably 40% by mass or less, more preferably 35% by mass or less, and even more preferably 30% by mass or less. It should be noted that the BHMF content can be determined according to the method described in the examples.

[0094] Regarding the content of the furan resin in the aforementioned adhesive resin, from the viewpoint of improving mold strength, it is preferably 30% by mass or more, more preferably 35% by mass or more, further preferably 40% by mass or more, and even more preferably 45% by mass or more. Regarding the content of the furan resin in the aforementioned adhesive resin, from the viewpoint of improving mold strength, it is preferably 60% by mass or less, more preferably 58% by mass or less. It should be noted that the content of the furan resin can be determined according to the method described in the examples.

[0095] <Binder Composition for Casting Molding>

[0096] The mold-making adhesive composition of this embodiment (hereinafter also simply referred to as the adhesive composition) contains furanol (component A), BHMF (component B), the aforementioned furan resin (component C), and water (component D), and

[0097] The following conditions (1) to (4) must be met.

[0098] Condition (1): The content of component A in the above adhesive composition is 30% by mass or less;

[0099] Condition (2): The content of component B in the above-mentioned adhesive composition is 7% by mass or more;

[0100] Condition (3): The content of component D in the above adhesive composition is 25% by mass or less;

[0101] Condition (4): In 100g of the above binder composition, the content of the above catalyst a is 0.01g or more and 0.50g or less, and the content of the above neutral salt a, converted to acid, is 0.13g or more.

[0102] According to this embodiment, the binder composition for molding has a low content of monomeric furanol and a high content of BHMF, low viscosity, and can improve the strength of the mold.

[0103] [Furfural (Component A)]

[0104] Regarding the content of component A in the above-mentioned adhesive composition, from the viewpoint of improving the working environment, it is 30% by mass or less, preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less. Regarding the content of component A in the above-mentioned adhesive composition, from the viewpoint of improving mold strength and reducing viscosity, it is preferably greater than 0% by mass, more preferably 5% by mass or more, even more preferably 10% by mass or more, even more preferably 15% by mass or more, and even more preferably 20% by mass or more.

[0105] [BHMF (Ingredient B)]

[0106] Regarding the content of component B in the above-mentioned binder composition, from the viewpoint of improving mold strength, it is 7% by mass or more, preferably 8% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more. Regarding the content of component B in the above-mentioned binder composition, from the viewpoint of suppressing the precipitation of BHMF, it is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less.

[0107] [Furan resin (component C)]

[0108] Regarding the content of component C in the above-mentioned adhesive composition, from the viewpoint of improving mold flexibility, it is preferably 25% by mass or more, more preferably 27% by mass or more, and even more preferably 28% by mass or more. Regarding the content of component C in the above-mentioned adhesive composition, from the viewpoint of reducing viscosity and improving mold strength, it is preferably 50% by mass or less, more preferably 49% by mass or less.

[0109] Regarding the ratio of the content of component C to the content of component B in the above-described adhesive composition (content of component C / content of component B), from the viewpoint of improving mold flexibility, it is preferably 1 or more, more preferably 1.4 or more, and even more preferably 2 or more. Regarding the ratio of the content of component C to the content of component B in the above-described adhesive composition, from the viewpoint of reducing viscosity and improving mold strength, it is preferably 7 or less, more preferably 6 or less, even more preferably 5 or less, even more preferably 4 or less, and even more preferably 3 or less.

[0110] [Water (Composition D)]

[0111] Regarding the content of component D in the above-described adhesive composition, from the viewpoint of improving mold strength, it is 25% by mass or less, preferably 20% by mass or less. Regarding the content of component D in the above-described adhesive composition, from the viewpoint of reducing viscosity, it is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more. It should be noted that the content of component D can be determined according to the method described in the examples.

[0112] [catalyst a]

[0113] Regarding the content of catalyst a in 100g of the above-mentioned binder composition, from the viewpoint of improving mold strength, it is 0.01g or more, preferably 0.02g or more, more preferably 0.025g or more, and even more preferably 0.03g or more. Regarding the content of catalyst a in 100g of the above-mentioned binder composition, from the viewpoint of improving mold strength and suppressing the precipitation of neutralizing salt a, it is 0.50g or less, more preferably 0.40g or less, more preferably 0.20g or less, even more preferably 0.13g or less, and even more preferably 0.10g or less.

[0114] [Neutralizing Salt a]

[0115] Regarding the content of the neutralizing salt a in 100g of the above-mentioned binder composition, from the viewpoint of improving mold strength, it is 0.13g or more, preferably 0.19g or more, and more preferably 0.3g or more, converted to acid. Regarding the content of the neutralizing salt a in 100g of the above-mentioned binder composition, from the viewpoint of improving mold strength and suppressing the precipitation of the neutralizing salt a, it is preferably 15g or less, more preferably 11g or less, further preferably 6g or less, and even more preferably 2.2g or less.

[0116] Regarding the total amount of catalyst a and neutral salt a converted to acid in 100g of the above-mentioned binder composition, from the viewpoint of improving mold strength, it is preferably 0.2g or more, more preferably 0.3g or more, further preferably 0.4g or more, and even more preferably 0.5g or more. Regarding the total amount of catalyst a and neutral salt a converted to acid in 100g of the above-mentioned binder composition, from the viewpoints of improving mold strength, suppressing the precipitation of neutral salt a, and economy, it is preferably 15g or less, more preferably 11g or less, further preferably 6g or less, and even more preferably 2.5g or less.

[0117] Regarding the ratio of the content of neutralizing salt a converted to acid in 100g of the above-mentioned binder composition to the total amount of the content of catalyst a and the content of neutralizing salt a converted to acid [content of neutralizing salt a converted to acid / (content of catalyst a + content of neutralizing salt a converted to acid)], from the viewpoint of improving mold strength, it is preferably 0.25 or more, more preferably 0.30 or more, even more preferably 0.50 or more, even more preferably 0.85 or more, even more preferably 0.90 or more, even more preferably 0.93 or more. From the same viewpoint, it is preferably less than 1, more preferably 0.97 or less, and even more preferably 0.96 or less.

[0118] [Curing Accelerator]

[0119] From the viewpoint of improving mold strength, the above-mentioned binder composition may contain a curing accelerator. As a curing accelerator, from the viewpoint of improving mold strength, it is preferably selected from one or more of the group consisting of phenolic derivatives, aromatic dialdehydes and tannins.

[0120] Examples of the phenolic derivatives mentioned above include resorcinol, cresol, hydroquinone, phloroglucinol, and methylene bisphenol. Regarding the content of the phenolic derivatives in the above-mentioned adhesive composition, from the viewpoint of improving mold strength, it is preferably 1 to 25% by mass, more preferably 2 to 15% by mass, and even more preferably 3 to 10% by mass.

[0121] Examples of the aforementioned aromatic dialdehydes include terephthalaldehyde, o-phthalaldehyde, and iso-phthalaldehyde, as well as their derivatives. These derivatives refer to compounds having alkyl or other substituents on the aromatic ring of an aromatic compound having two formyl groups as its basic skeleton. Regarding the content of the aromatic dialdehyde in the aforementioned adhesive composition, from the viewpoint of ensuring sufficient dissolution of the aromatic dialdehyde in the furan resin and suppressing the odor of the aromatic dialdehyde itself, it is preferably 0.1 to 15% by mass, more preferably 0.5 to 10% by mass, and even more preferably 1 to 5% by mass.

[0122] Examples of the aforementioned tannins include condensed tannins and hydrolyzed tannins. Examples of these condensed tannins and hydrolyzed tannins include tannins with pyrogallol or resorcinol skeletons. Additionally, bark extracts containing these tannins, extracts obtained from natural sources such as leaves, fruits, seeds, and galls of insects parasitizing plants, can be added. Regarding the tannin content in the aforementioned adhesive composition, from the viewpoints of improving curing speed and mold strength, it is preferably 0.2 to 10% by mass, more preferably 1.0 to 7% by mass, and even more preferably 1.9 to 5% by mass.

[0123] Regarding the viscosity of the above-mentioned adhesive composition at 25°C, from the viewpoint of workability during the manufacture of the mold composition and the mold manufacturing process, it is preferably 120 mPa·s or less, more preferably 70 mPa·s or less, and even more preferably 60 mPa·s or less. It should be noted that the viscosity of the adhesive composition at 25°C can be measured according to the method described in the examples.

[0124] The above-mentioned adhesive composition may also contain additives such as silane coupling agents. For example, if the above-mentioned adhesive composition contains a silane coupling agent, the final strength of the obtained mold can be further improved, which is therefore preferred. As a silane coupling agent, amino silanes such as N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltriethoxysilane, and 3-aminopropyltrimethoxysilane can be used; epoxy silanes such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyltriethoxysilane can be used; ureosilanes; mercaptosilanes; thioether silanes; methacryloxysilanes; and acryloyloxysilanes can be used. Preferably, it is an aminosilane, an epoxysilane, or a ureosilane. More preferably, it is an aminosilane or an epoxysilane. Among aminosilanes, N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane is preferred. Among epoxysilanes, 3-glycidoxypropylmethyldimethoxysilane is preferred.

[0125] Regarding the content of the silane coupling agent in the above-mentioned adhesive composition, from the viewpoint of improving mold strength, it is preferably 0.01% by mass or more, more preferably 0.05% by mass or more. Similarly, regarding the content of the silane coupling agent in the above-mentioned adhesive composition, it is preferably 5% by mass or less, more preferably 3% by mass or less, further preferably 1% by mass or less, and even more preferably 0.5% by mass or less.

[0126] The binder composition for molding according to this embodiment is suitable for molding self-hardening molds. Here, a self-hardening mold refers to a mold in which a polymerization reaction occurs over time when the binder composition and a hardener are mixed into sand, resulting in mold curing. The temperature of the sand used at this time is in the range of -20°C to 50°C, preferably 0°C to 40°C. By selecting a suitable amount of hardener for sand at this temperature and adding it to the sand, the mold can be properly cured.

[0127] <Molding and Molding Composition>

[0128] The mold-making composition of this embodiment contains the above-described adhesive composition and a curing agent composition containing a curing agent for curing the mold-making adhesive composition. The mold-making composition of this embodiment has the same effects as the above-described adhesive composition.

[0129] [Curing agent composition]

[0130] The curing agent composition described above can be used without particular limitation as long as it contains a curing agent that cures the adhesive composition described above. Examples of such curing agents include acid-based curing agents, such as sulfonic acid compounds like xylenesulfonic acid (especially m-xylenesulfonic acid), toluenesulfonic acid (especially p-toluenesulfonic acid), and methanesulfonic acid; phosphoric acid compounds like phosphoric acid and acidic phosphate esters; and one or more conventionally known compounds such as sulfuric acid. From an operability point of view, aqueous solutions are preferred for these compounds. Furthermore, the curing agent composition may contain one or more solvents selected from the group consisting of alcohols, ether alcohols, and esters, or carboxylic acids.

[0131] The content of the solvent in the above-mentioned curing agent composition can be appropriately adjusted according to the temperature of the working environment or the temperature of the refractory particles to obtain the required reaction rate and mold strength. However, generally speaking, from the viewpoint of dissolving the curing agent composition, it is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more. Regarding the content of the solvent in the above-mentioned curing agent composition, from the viewpoint of improving mold strength, it is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less.

[0132] Regarding the content of the curing agent in the above-described curing agent composition, from the viewpoint of improving mold strength, it is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more. Regarding the content of the curing agent in the above-described curing agent composition, from the viewpoint of dissolving the curing agent composition, it is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 80% by mass or less.

[0133] Regarding the mass ratio of the above-mentioned adhesive composition to the above-mentioned curing agent, from the viewpoint of improving the curing speed and improving the mold strength, the curing agent is preferably 10 to 60 parts by mass relative to 100 parts by mass of the above-mentioned adhesive composition, more preferably 10 to 40 parts by mass, and even more preferably 10 to 30 parts by mass.

[0134] [Molding Composition]

[0135] The mold-making composition of this embodiment contains refractory particles, the above-described binder composition, and the above-described curing agent composition. The mold-making composition of this embodiment has the same effects as the above-described binder composition.

[0136] [Refractory Particles]

[0137] As the aforementioned refractory particles, one or more of the conventionally known materials such as silica sand, chrome sand, zircon sand, olivine sand, alumina sand, mullite sand, and synthetic mullite sand can be used. Alternatively, materials obtained by recycling or regenerating used refractory particles can also be used. Among these, silica sand is preferred.

[0138] In the above-mentioned mold composition, the mass ratio of the refractory particles, the binder composition, and the curing agent can be appropriately set. From the viewpoint of improving the curing speed and improving the mold strength, the binder composition is preferably 0.5 to 1.5 parts by mass relative to 100 parts by mass of the refractory particles, and the curing agent is in the range of 0.07 to 1 part by mass.

[0139] <Mold Manufacturing Method>

[0140] The method for manufacturing a mold according to this embodiment includes: a mixing step in which refractory particles, the aforementioned binder composition, and the aforementioned curing agent composition are mixed to obtain a mold composition; and a curing step in which the mold composition is filled into a mold frame and cured. This method for manufacturing a mold has the same effect as the aforementioned binder composition.

[0141] In the above mixing process, the order in which the binder composition, the curing agent composition, and the refractory particles are added and mixed is not particularly limited. The binder composition and the curing agent composition can be mixed to produce a mold-making composition, and then the mold-making composition can be mixed with the refractory particles. Alternatively, the binder composition, the curing agent composition, and the refractory particles can be added and mixed separately. However, from the viewpoint of maintaining stability and the productivity of the mold, it is preferable to mix the binder composition, the curing agent composition, and the refractory particles to obtain the mold-making composition. Furthermore, from the viewpoint of improving mold strength, it is preferable to add the curing agent composition to the refractory particles and mix them, and then add the binder composition and mix them. Additionally, when using two or more curing agent compositions, they can be mixed before being added, or they can be added separately.

[0142] In the above mixing process, as a method for mixing the raw materials, a known general method can be used, such as adding the raw materials using a batch mixer and mixing them, or feeding the raw materials to a continuous mixer and mixing them.

[0143] In the mold manufacturing method of this embodiment, apart from the mixing process, the mold can be manufactured directly using conventional mold manufacturing processes.

[0144] Regarding the above embodiments, the present invention further discloses the following compositions, manufacturing methods, or uses.

[0145] <1>

[0146] A method for manufacturing a molding binder resin, comprising a method for manufacturing a molding binder resin containing furanol, dihydroxymethylfuran, and furan resin.

[0147] The process includes step A, in which furan-methanol is reacted with formaldehyde in the presence of one or more catalysts selected from phosphoric acid and boric acid, and one or more neutralizing salts selected from phosphoric acid and boric acid.

[0148] In step A above, the amount of catalyst a used is 0.0002 moles or more and 0.01 moles or less relative to 1 mole of furan-methanol, and the amount of neutralizing salt a used is 0.003 moles or more of acid relative to 1 mole of furan-methanol.

[0149] <2>

[0150] The manufacturing method described in <1> is a method for manufacturing a molding binder resin containing furanol, dihydroxymethylfuran, and furan resin.

[0151] The process includes step A, in which furan-methanol is reacted with formaldehyde in the presence of one or more catalysts selected from phosphoric acid and boric acid, and one or more neutralizing salts selected from phosphoric acid and boric acid.

[0152] In step A above, the amount of catalyst a relative to 1 mole of furan-methanol is 0.0002 moles or more and 0.01 moles or less, and the amount of neutralizing salt a relative to 1 mole of furan-methanol is 0.003 moles or more and 0.15 moles or less, converted to acid.

[0153] The aforementioned neutralizing salt a is selected from one or more alkali metal salts and amine salts, and

[0154] The aforementioned furan resin is selected from one or more of the group consisting of: urea-modified furan resin, furan methanol and aldehyde condensate, and two or more co-condensates selected from urea-modified furan resin and furan methanol and aldehyde condensate.

[0155] <3>

[0156] The manufacturing method described in <1> or <2> is a method for manufacturing a molding binder resin containing furanol, dimethylolfuran, and furan resin.

[0157] The process includes step A, in which furan-methanol is reacted with formaldehyde in the presence of one or more catalysts selected from phosphoric acid and boric acid, and one or more neutralizing salts selected from phosphoric acid and boric acid.

[0158] In step A above, the amount of catalyst a relative to 1 mole of furan-methanol is 0.0004 moles or more and 0.008 moles or less, and the amount of neutralizing salt a relative to 1 mole of furan-methanol is converted to acid 0.005 moles or more and 0.04 moles or less.

[0159] The degree of neutralization of catalyst a [amount of neutralizing salt a / (amount of catalyst a + amount of neutralizing salt a)] is above 93% and below 97%.

[0160] The aforementioned neutralizing salt a is selected from one or more alkali metal salts and amine salts, and

[0161] The aforementioned furan resin is selected from one or more of the group consisting of: urea-modified furan resin, furan methanol and aldehyde condensate, and two or more co-condensates selected from urea-modified furan resin and furan methanol and aldehyde condensate.

[0162] <4>

[0163] The manufacturing method described in any of <1> to <3>, wherein the pH value of the reaction solution before the start of the reaction in step A is 2 or higher and 5.5 or lower.

[0164] <5>

[0165] In any of the manufacturing methods described in <1> to <4>, the content of furanol in the binder resin for molding the mold is 10% by mass or more and 30% by mass or less, the content of dihydroxymethylfuran is 8% by mass or more and 40% by mass or less, and the content of furan resin is 30% by mass or more and 60% by mass or less.

[0166] <6>

[0167] The manufacturing method described in any one of <1> to <5>, wherein the neutralizing salt a is an amine salt, and the amine salt is a tertiary amine salt having an alkyl group having 2 or more carbon atoms and less than 10 carbon atoms.

[0168] <7>

[0169] A molding adhesive composition comprising furanol (component A), dimethylolfuran (component B), furan resin (component C), and water (component D), and

[0170] The following conditions (1) to (4) must be met.

[0171] Condition (1): The content of component A in the above-mentioned mold molding binder composition is 30% by mass or less;

[0172] Condition (2): The content of component B in the above-mentioned mold molding binder composition is 7% by mass or more;

[0173] Condition (3): The content of component D in the above-mentioned mold molding binder composition is 25% by mass or less;

[0174] Condition (4): In 100g of the above-mentioned binder composition for molding molds, the content of one or more catalysts selected from phosphoric acid and boric acid is 0.01g or more and 0.50g or less, and the content of one or more neutral salts selected from phosphoric acid and boric acid, converted into acid, is 0.13g or more.

[0175] <8>

[0176] The mold-making adhesive composition described in <7> contains furanol (component A), dimethylolfuran (component B), furan resin (component C), and water (component D).

[0177] Furan resin is selected from one or more substances in the group consisting of: urea-modified furan resin, condensates of furan methanol and aldehydes, and co-condensates of two or more substances selected from urea-modified furan resin and condensates of furan methanol and aldehydes.

[0178] The following conditions (1) to (4) must be met.

[0179] Condition (1): The content of component A in the above-mentioned mold molding binder composition is greater than 0% by mass and less than 30% by mass;

[0180] Condition (2): The content of component B in the above-mentioned mold molding binder composition is 7% by mass or more and 30% by mass or less;

[0181] Condition (3): The content of component D in the above-mentioned mold molding binder composition is 5% by mass or more and 25% by mass or less;

[0182] Condition (4): In 100g of the above-mentioned binder composition for molding molds, the content of one or more catalysts a selected from phosphoric acid and boric acid is 0.01g or more and 0.50g or less, and the content of one or more neutral salts a selected from phosphoric acid and boric acid, converted into acid, is 0.13g or more and 15g or less, and the neutral salt a is selected from one or more alkali metal salts and amine salts.

[0183] <9>

[0184] The mold-making adhesive composition described in <7> or <8> contains furanol (component A), dimethylolfuran (component B), furan resin (component C), and water (component D).

[0185] Furan resin is selected from one or more substances in the group consisting of: urea-modified furan resin, condensates of furan methanol and aldehydes, and co-condensates of two or more substances selected from urea-modified furan resin and condensates of furan methanol and aldehydes.

[0186] The ratio of the content of component C to the content of component B (content of component C / content of component B) is greater than 1 and less than 7, and

[0187] The following conditions (1) to (4) must be met.

[0188] Condition (1): The content of component A in the above-mentioned mold molding binder composition is 10% by mass or more and 30% by mass or less;

[0189] Condition (2): The content of component B in the above-mentioned mold molding binder composition is 7% by mass or more and 25% by mass or less;

[0190] Condition (3): The content of component D in the above-mentioned mold molding binder composition is 10% by mass or more and 25% by mass or less;

[0191] Condition (4): In 100g of the above-mentioned binder composition for molding molds, the content of one or more catalysts a selected from phosphoric acid and boric acid is 0.01g or more and 0.50g or less, and the content of one or more neutral salts a selected from phosphoric acid and boric acid, converted into acid, is 0.13g or more and 15g or less, and the neutral salt a is selected from one or more alkali metal salts and amine salts.

[0192] <10>

[0193] The molding binder composition described in any of <7> to <9> contains furanol (component A), dimethylolfuran (component B), furan resin (component C), and water (component D).

[0194] Furan resin is selected from one or more substances in the group consisting of: urea-modified furan resin, condensates of furan methanol and aldehydes, and co-condensates of two or more substances selected from urea-modified furan resin and condensates of furan methanol and aldehydes.

[0195] The ratio of the content of component C to the content of component B (content of component C / content of component B) is greater than 1 and less than 7.

[0196] The ratio of the acid content of neutralizing salt a to the total acid content of catalyst a [acid content of neutralizing salt a / (acid content of catalyst a + acid content of neutralizing salt a)] is greater than 0.93 and less than 0.97.

[0197] The following conditions (1) to (4) must be met.

[0198] Condition (1): The content of component A in the above-mentioned mold molding binder composition is 10% by mass or more and 30% by mass or less;

[0199] Condition (2): The content of component B in the above-mentioned mold molding binder composition is 7% by mass or more and 25% by mass or less;

[0200] Condition (3): The content of component D in the above-mentioned mold molding binder composition is 10% by mass or more and 25% by mass or less;

[0201] Condition (4): In 100g of the above-mentioned binder composition for molding molds, the content of one or more catalysts a selected from phosphoric acid and boric acid is 0.025g or more and 0.40g or less, and the content of one or more neutral salts a selected from phosphoric acid and boric acid, converted into acid, is 0.3g or more and 2.2g or less, and the neutral salt a is selected from one or more alkali metal salts and amine salts.

[0202] <11>

[0203] The mold-forming adhesive composition described in any one of <7> to <10>, wherein the content of the aforementioned component C is 25% by mass or more and 50% by mass or less.

[0204] <12>

[0205] The mold-forming binder composition described in any one of <7> to <11>, wherein the neutralizing salt a is an amine salt, and the amine salt is a tertiary amine salt having an alkyl group having 2 or more carbon atoms and less than 10 carbon atoms.

[0206] <13>

[0207] A mold-forming composition comprising a mold-forming adhesive composition as described in any one of <7> to <12>, and a curing agent composition comprising a curing agent for curing the mold-forming adhesive composition.

[0208] <14>

[0209] A mold composition comprising refractory particles, a mold-forming adhesive composition as described in any one of <7> to <12>, and a curing agent composition comprising a curing agent for curing the mold-forming adhesive composition.

[0210] <15>

[0211] A method for manufacturing a mold includes: a mixing step in which refractory particles, a mold-forming adhesive composition as described in any one of <7> to <12>, and a curing agent composition comprising a curing agent for curing the mold-forming adhesive composition are mixed to obtain a mold composition; and a curing step in which the mold composition is filled into a mold frame and the mold composition is cured.

[0212] Example

[0213] Hereinafter, specific embodiments of the present invention will be described.

[0214] <Methods for Determining Physical Properties>

[0215] [Water content]

[0216] The moisture content was measured using an automatic moisture measuring device (manufactured by Hiranuma Sangyo Co., Ltd., AQV-2200A) based on the Karl von Somdej method as shown in JIS K 0068.

[0217] [Content of furanol and dimethylolfuran]

[0218] The determination was performed using a gas chromatograph (manufactured by Shimadzu Corporation, GC-2014S) under the following conditions.

[0219] • Standard curve: prepared using furanol and dihydroxymethylfuran.

[0220] Internal standard solution: 1,6-hexanediol

[0221] • Column: PEG-20M Chromosorb WAW DMCS 60 / 80mesh (manufactured by GL Sciences)

[0222] • Column temperature: 80~200℃ (8℃ / min)

[0223] Injection temperature: 210℃

[0224] • Detector temperature: 250℃; Carrier gas: 50 mL / min (He)

[0225] [Furan resin content]

[0226] The content of furan resin is calculated by subtracting the contents of furan methanol, water, BHMF, and silane coupling agent.

[0227] [Measurement of pH value of the reaction solution before the reaction begins]

[0228] A 50% aqueous solution was prepared using a pH meter (manufactured by Yokogawa Electric Corporation, personal pH meter PH71) and measured at 25°C.

[0229] [Content of unneutralized phosphoric acid and boric acid, and content of mono-neutralized salts of phosphoric acid and boric acid]

[0230] The determination was performed using a potentiometric titration apparatus (HIRANUMA Co., Ltd., COM-A19S, titrant: 0.1 mol / L cyclohexylamine). The content of unneutralized phosphoric acid and boric acid was determined based on the titration amount up to the first inflection point at approximately pH 4. The content of phosphoric acid and boric acid was determined based on the titration amount from the first inflection point to the second inflection point at approximately pH 9. The content of a neutralized salt of phosphoric acid and boric acid was calculated based on the difference between these titration amounts.

[0231] [Viscosity]

[0232] Viscosity was measured at 25°C using an E-type viscometer (RE-80R, manufactured by Toki Sangyo Co., Ltd.) with a standard rotor (cone angle 1°34', cone radius: 24mm) at a rotation speed of 100 rpm.

[0233] <Example>

[0234] [Example 1-1]

[0235] To a three-necked flask equipped with a stirrer, condenser, and thermometer, 713.86 g of furanyl alcohol, 7.04 g of 48% sodium hydroxide aqueous solution, and 201.88 g of 92% paraformaldehyde were added while stirring, and the mixture was heated to 60°C using a heating mantle. After cooling to 30°C with water, 10.04 g of 85% phosphoric acid aqueous solution was added. The phosphoric acid content was 0.0003 mol relative to 1 mol of furanyl alcohol, and the phosphate monosodium salt content was 0.0117 mol relative to 1 mol of furanyl alcohol. The pH value of the reaction solution was measured before the reaction began, and the temperature was raised to 100°C. The reaction was allowed to proceed until the furanyl alcohol monomer reached 33% to obtain the resin of intermediate product manufacturing example 1. The time until the furanyl alcohol reached 33% by mass and the BHMF content at that point are shown in Table 1.

[0236] [Examples 1-2 to 1-17 and Comparative Examples 1-1 to 1-6]

[0237] Using the base types shown in Table 1, the amounts of base types were varied in order to become the amount of phosphoric acid and the amount of phosphate neutral salt. Otherwise, the process was carried out in the same manner as in Examples 1-1 to obtain the resins of intermediate product manufacturing Examples 2-17 and 51-56. The time until the furan-methanol concentration (content) in the reaction solution reached 33% by mass and the BHMF concentration (content) at that time are shown in Table 1.

[0238] [Examples 1-18]

[0239] Boric acid was used as an acid catalyst, and the amount of base was varied in the manner shown in Table 1, with the amounts of boric acid and boric acid-neutralized salt being the same as in Examples 1-1. Otherwise, the process was carried out in the same manner as in Examples 1-1 to obtain the resin of Intermediate Product Manufacturing Example 18. The time until furan-methanol reached 33% and the amount of BHMF at that time are shown in Table 1. It should be noted that in each table, FFA refers to furan-methanol.

[0240] [Table 1]

[0241]

[0242] ※1: The time until the amount of alcohol in the furan in the reaction solution decreases to 33%.

[0243] [Examples 2-1 to 2-18, Comparative Examples 2-1 to 2-6]

[0244] For the 932.82 g of resin obtained in intermediate product manufacturing examples 1-18 and 51-56, 57.10 g of urea was added to the same reaction apparatus, and the reaction was carried out at 105°C for 1 hour. Afterward, the apparatus was cooled to 70°C with air, and 10.08 g of urea was added. The reaction was carried out at 70°C for 20 minutes to obtain reaction-finished products 1-18 and reaction-finished products 51-56. The composition of each reaction-finished product is shown in Table 2.

[0245] [Example 2-19]

[0246] Compared with the 932.82 g of resin obtained in intermediate product manufacturing example 2, 57.10 g of urea was added to the same reaction apparatus and reacted at 105°C for 1 hour to obtain reaction product 19. The composition of reaction product 19 is shown in Table 2.

[0247] [Example 2-20]

[0248] The intermediate product manufacturing example 2 was used as the reaction end product 20.

[0249] [Examples 3-1 to 3-19, Comparative Examples 3-1 to 3-6]

[0250] Using the reaction end products 1-19 and 51-56 obtained in the above manufacturing examples, furanol, water, and silane coupling agent, the mixtures were formulated with furanol content of about 19% by mass and water content of about 24% by mass to obtain the mold molding binder compositions of Examples 3-1 to 3-19 and Comparative Examples 3-1 to 3-6.

[0251] [Example 4-1, Comparative Example 4-1]

[0252] Using the reaction end products 2 and 54 obtained in the above manufacturing example, furanol, water, and silane coupling agent, the mixtures were prepared in such a manner that the furanol content was about 19% by mass and the water content was about 15% by mass to obtain the mold molding binder compositions of Example 4-1 and Comparative Example 4-1.

[0253] [Example 5-1, Comparative Example 5-1]

[0254] Using the reaction end products 2 and 54 obtained in the above manufacturing example, furanol, water, and silane coupling agent, the furanol content is about 25% by mass and the water content is about 15% by mass, to obtain the mold molding binder compositions of Example 5-1 and Comparative Example 5-1.

[0255] [Examples 6-1 to 6-2, Comparative Example 6-1]

[0256] Using the reaction end products 2, 20 and 54 obtained in the above manufacturing example, furanol, water and silane coupling agent, the furanol content is about 25% by mass and the water content is about 24% by mass, to obtain the mold molding binder compositions of Example 6-1, Example 6-2 and Comparative Example 6-1.

[0257] [Table 2]

[0258]

[0259] <Example of manufacturing composition for casting molds>

[0260] Under conditions of 25°C and 55% RH, a curing agent composition was added to 100 parts by weight of furan-regenerated silica sand, followed by 0.8 parts by weight of the molding binder compositions shown in Tables 4-6. These were mixed to obtain a molding composition. It should be noted that the curing agent composition was a xylenesulfonic acid / sulfuric acid-based curing agent (Kao Lightener US-3, Kao Lightener C-21: manufactured by Kao-Quaker). The amount of curing agent composition added was set to 0.32 parts by weight relative to 100 parts by weight of furan-regenerated silica sand, and the ratio of Kao Lightener US-3 to Kao Lightener C-21 was adjusted so that the compressive strength of the samples described later after 30 minutes was 0.20–0.35 MPa.

[0261] <Evaluation of mold compressive strength>

[0262] The freshly mixed mold-making composition was filled into a cylindrical sample frame with a diameter of 50 mm and a height of 50 mm. After 30 minutes, the sample was demolded, and the compressive strength (MPa) was measured using the method described in JIS Z2604-1976. This strength was taken as the compressive strength after 30 minutes. The compressive strength after 30 minutes was used as the standard for curing speed to confirm whether the curing dosage was appropriate. In addition, the mold-making composition was similarly filled into the sample frame, and after 2 hours, the sample was demolded. Twenty-four hours after filling, the compressive strength (MPa) was measured using the method described in JIS Z 2604-1976, and this was taken as the "compressive strength after 24 hours". A higher value indicates a higher mold strength. The evaluation results are shown in Tables 3-6.

[0263] [Table 3]

[0264]

[0265] [Table 4]

[0266]

[0267] [Table 5]

[0268]

[0269] [Table 6]

[0270]

Claims

1. A method for manufacturing a molding binder resin, comprising a method for manufacturing a molding binder resin containing furanol, dimethylolfuran, and furan resin. The manufacturing method includes step A, which involves reacting furan-methanol with formaldehyde in the presence of one or more catalysts selected from phosphoric acid and boric acid, and one or more neutralizing salts selected from phosphoric acid and boric acid. In step A, the amount of catalyst a relative to 1 mole of furan-methanol is 0.0002 mol or more and 0.01 mol or less, and the amount of neutralizing salt a relative to 1 mole of furan-methanol is 0.003 mol or more and 0.15 mol or less, converted to acid. The neutralizing salt a is selected from one or more alkali metal salts and amine salts.

2. The manufacturing method according to claim 1, wherein, The pH value of the reaction solution before the start of the reaction in step A is above 2 and below 5.

5.

3. The manufacturing method according to claim 1 or 2, wherein, The neutralizing salt a is an amine salt, which is a tertiary amine salt having an alkyl group having 2 or more carbon atoms and less than 10 carbon atoms.

4. The manufacturing method according to claim 1 or 2, wherein, The content of furan-methanol in the adhesive resin used for molding is less than 30% by mass.

5. The manufacturing method according to claim 1 or 2, wherein, The content of dihydroxymethylfuran in the adhesive resin used for molding is 8% by mass or more.

6. The manufacturing method according to claim 1 or 2, wherein, The content of furan-methanol in the adhesive resin used for molding is 10% by mass or more.

7. The manufacturing method according to claim 1 or 2, wherein, The content of dihydroxymethylfuran in the adhesive resin used for molding is less than 40% by mass.

8. The manufacturing method according to claim 1 or 2, wherein, The content of furan resin in the adhesive resin used for molding is more than 30% by mass and less than 60% by mass.

9. The manufacturing method according to claim 1 or 2, wherein, The furan resin is one or more of the following substances: urea-modified furan resin, furan methanol and aldehyde condensate, and two or more co-condensates selected from urea-modified furan resin and furan methanol and aldehyde condensate.

10. The manufacturing method according to claim 1 or 2, wherein, The degree of neutralization of catalyst a, i.e., neutral salt a / (catalyst a + neutral salt a), is greater than 25% and less than 100%.

11. The manufacturing method according to claim 1 or 2, wherein the method comprises manufacturing a molding binder resin containing furanol, dimethylolfuran, and furan resin. The manufacturing method includes step A, which involves reacting furan-methanol with formaldehyde in the presence of one or more catalysts selected from phosphoric acid and boric acid, and one or more neutralizing salts selected from phosphoric acid and boric acid. In step A, the amount of catalyst a relative to 1 mole of furan-methanol is 0.0004 mol or more and 0.008 mol or less, and the amount of neutralizing salt a relative to 1 mole of furan-methanol is 0.005 mol or more and 0.04 mol or less, converted to acid. The neutralizing salt a is selected from one or more alkali metal salts and amine salts. The furan resin is one or more of the following substances: urea-modified furan resin, furan methanol and aldehyde condensate, and two or more co-condensates selected from urea-modified furan resin and furan methanol and aldehyde condensate.

12. The manufacturing method according to claim 1 or 2, wherein the method comprises manufacturing a molding binder resin containing furanol, dimethylolfuran, and furan resin. The manufacturing method includes step A, which involves reacting furan-methanol with formaldehyde in the presence of one or more catalysts selected from phosphoric acid and boric acid, and one or more neutralizing salts selected from phosphoric acid and boric acid. In step A, the amount of catalyst a relative to 1 mole of furan-methanol is 0.0004 mol or more and 0.008 mol or less, and the amount of neutralizing salt a relative to 1 mole of furan-methanol is 0.005 mol or more and 0.04 mol or less, converted to acid. The degree of neutralization of catalyst a, i.e., the ratio of the amount of neutralizing salt a to (the amount of catalyst a + the amount of neutralizing salt a), is above 93% and below 97%. The neutralizing salt a is selected from one or more alkali metal salts and amine salts. The furan resin is selected from one or more of the following: urea-modified furan resin, furan methanol and aldehyde condensate, and two or more co-condensates selected from urea-modified furan resin and furan methanol and aldehyde condensate.

13. The manufacturing method according to claim 1 or 2, wherein, The content of furanol in the adhesive resin used for molding is 10% by mass or more and 30% by mass or less, the content of dihydroxymethylfuran is 8% by mass or more and 40% by mass or less, and the content of furan resin is 30% by mass or more and 60% by mass or less.

14. A binder composition for molding, comprising furanol (component A), dihydroxymethylfuran (component B), furan resin (component C), and water (component D), and The following conditions (1) to (4) must be met: Condition (1): The content of component A in the adhesive composition for molding the mold is greater than 0% by mass and less than 30% by mass; Condition (2): The content of component B in the adhesive composition for molding the mold is 7% by mass or more and 30% by mass or less; Condition (3): The content of component D in the adhesive composition for molding the mold is greater than 0% by mass and less than 25% by mass; Condition (4): In 100 g of the binder composition for molding the mold, the content of one or more catalysts a selected from phosphoric acid and boric acid is 0.01 g or more and 0.50 g or less, and the content of one or more neutral salts a selected from phosphoric acid and boric acid, converted into acid, is 0.13 g or more and 15 g or less, wherein the neutral salt a is selected from one or more alkali metal salts and amine salts.

15. The adhesive composition for molding according to claim 14, wherein, The furan resin contains one or more of the following substances: urea-modified furan resin, furan methanol and aldehyde condensate, and two or more co-condensates selected from urea-modified furan resin and furan methanol and aldehyde condensate.

16. The adhesive composition for molding according to claim 14 or 15, wherein, The sum of the content of catalyst a in 100 g of the binder composition for molding the mold and the content of neutralizing salt a converted to acid is 0.2 g or more and 15 g or less.

17. The adhesive composition for molding according to claim 14 or 15, wherein, The ratio of the content of component C to the content of component B in the adhesive composition for molding is such that the content of component C / content of component B is 1 or more and 7 or less.

18. The adhesive composition for molding according to claim 14 or 15, wherein, The content of component C in the adhesive composition for molding is 25% by mass or more and 50% by mass or less.

19. The adhesive composition for molding according to claim 14 or 15, wherein, The content of component D in the adhesive composition for molding the mold is 5% by mass or more.

20. The adhesive composition for molding according to claim 14 or 15, wherein, The ratio of the acid content of neutral salt a to the total amount of catalyst a and the acid content of neutral salt a, i.e., the acid content of neutral salt a / (catalyst a + acid content of neutral salt a) is greater than 0.25 and less than 1.

21. The adhesive composition for molding according to claim 14 or 15, wherein, The neutralizing salt a is an amine salt, which is a tertiary amine salt having an alkyl group having 2 or more carbon atoms and less than 10 carbon atoms.

22. The adhesive composition for molding according to claim 14 or 15, wherein, The adhesive composition for molding contains a silane coupling agent.

23. The adhesive composition for molding according to claim 22, wherein, The content of silane coupling agent in the adhesive composition for molding is more than 0.01% by mass and less than 5% by mass.

24. The mold-making adhesive composition according to claim 14 or 15, comprising furanol (component A), dimethylolfuran (component B), furan resin (component C), and water (component D). Furan resin is one or more of the following substances: urea-modified furan resin, condensate of furan methanol and aldehydes, and co-condensate of two or more substances selected from urea-modified furan resin and condensate of furan methanol and aldehydes. The adhesive composition for molding the mold satisfies the following conditions (1) to (4): Condition (1): The content of component A in the adhesive composition for molding the mold is greater than 0% by mass and less than 30% by mass; Condition (2): The content of component B in the adhesive composition for molding the mold is 7% by mass or more and 30% by mass or less; Condition (3): The content of component D in the adhesive composition for molding the mold is 5% by mass or more and 25% by mass or less; Condition (4): In 100 g of the binder composition for molding the mold, the content of one or more catalysts a selected from phosphoric acid and boric acid is 0.01 g or more and 0.50 g or less, and the content of one or more neutral salts a selected from phosphoric acid and boric acid, converted to acid, is 0.13 g or more and 15 g or less, wherein the neutral salt a is selected from one or more alkali metal salts and amine salts.

25. The mold-forming adhesive composition according to claim 14 or 15, comprising furanol (component A), dimethylolfuran (component B), furan resin (component C), and water (component D). Furan resin is one or more of the following substances: urea-modified furan resin, condensate of furan methanol and aldehydes, and co-condensate of two or more substances selected from urea-modified furan resin and condensate of furan methanol and aldehydes. The ratio of the content of component C to the content of component B, i.e., the content of component C / content of component B, is greater than 1 and less than 7. The adhesive composition for molding the mold satisfies the following conditions (1) to (4): Condition (1): The content of component A in the adhesive composition for molding the mold is 10% by mass or more and 30% by mass or less; Condition (2): The content of component B in the adhesive composition for molding the mold is 7% by mass or more and 25% by mass or less; Condition (3): The content of component D in the adhesive composition for molding the mold is 10% by mass or more and 25% by mass or less; Condition (4): In 100 g of the binder composition for molding the mold, the content of one or more catalysts a selected from phosphoric acid and boric acid is 0.01 g or more and 0.50 g or less, and the content of one or more neutral salts a selected from phosphoric acid and boric acid, converted into acid, is 0.13 g or more and 15 g or less, and the neutral salt a is selected from one or more alkali metal salts and amine salts.

26. The mold-forming adhesive composition according to claim 14 or 15, comprising furanol (component A), dimethylolfuran (component B), furan resin (component C), and water (component D). Furan resin is one or more of the following substances: urea-modified furan resin, condensate of furan methanol and aldehydes, and co-condensate of two or more substances selected from urea-modified furan resin and condensate of furan methanol and aldehydes. The ratio of the content of component C to the content of component B, i.e., the content of component C / content of component B, is greater than 1 and less than 7. The ratio of the acid content of neutral salt a to the total acid content of catalyst a, i.e., the ratio of the acid content of neutral salt a / (acid content of catalyst a + acid content of neutral salt a), is greater than 0.93 and less than 0.

97. The adhesive composition for molding the mold satisfies the following conditions (1) to (4): Condition (1): The content of component A in the adhesive composition for molding the mold is 10% by mass or more and 30% by mass or less; Condition (2): The content of component B in the adhesive composition for molding the mold is 7% by mass or more and 25% by mass or less; Condition (3): The content of component D in the adhesive composition for molding the mold is 10% by mass or more and 25% by mass or less; Condition (4): In 100 g of the binder composition for molding the mold, the content of one or more catalysts a selected from phosphoric acid and boric acid is 0.025 g or more and 0.40 g or less, and the content of one or more neutral salts a selected from phosphoric acid and boric acid, converted into acid, is 0.3 g or more and 2.2 g or less, and the neutral salt a is selected from one or more alkali metal salts and amine salts.

27. A mold-forming composition comprising a mold-forming adhesive composition according to any one of claims 14 to 26, and a curing agent composition, wherein the curing agent composition comprises a curing agent for curing the mold-forming adhesive composition.

28. A mold composition comprising refractory particles, a mold-forming adhesive composition according to any one of claims 14 to 26, and a curing agent composition, said curing agent composition comprising a curing agent for curing the mold-forming adhesive composition.

29. A method for manufacturing a casting mold, comprising the following steps: A mixing process comprising mixing refractory particles, a molding binder composition for casting as described in any one of claims 14 to 26, and a curing agent composition to obtain a molding composition, wherein the curing agent composition comprises a curing agent for curing the molding binder composition; and The curing process involves filling the mold composition into a mold frame and curing the mold composition.

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