WO2015098642A1

WO2015098642A1 - Composition for forming mold, method for producing self-curing mold, and kit for forming self-curing mold

Info

Publication number: WO2015098642A1
Application number: PCT/JP2014/083370
Authority: WO
Inventors: 宏明青沼; 崇志情家; 俊樹松尾
Original assignee: 花王株式会社
Priority date: 2013-12-25
Filing date: 2014-12-17
Publication date: 2015-07-02
Also published as: JP2015142939A; CN105848805B; CN107812879B; CN107812879A; CN105848805A; JP6363938B2

Abstract

This composition for forming a mold comprises furfural, urea, and 2,6-dihydroxybenzoic acid, and the furfural content is 18.0 to 55.0 mass%. By means of this composition for forming a mold, the mold curing speed can be raised without using an acid having sulfur atoms and the problem of work environment deterioration associated with SO_x can be solved.

Description

[Name of invention determined by ISA based on Rule 37.2] Composition for mold making, method for producing self-hardening mold, and kit for self-hardening mold making

The present invention relates to a mold making composition.

In general, an acid-curable self-hardening mold is composed of a binder composition for mold making containing an acid-curable resin in refractory particles such as silica sand, and a curing agent composition containing a sulfonic acid, sulfuric acid, phosphoric acid, etc. And kneading these, the obtained kneaded sand is filled into a mold such as a wooden mold, and the acid curable resin is cured to produce. Furan resin, phenol resin, etc. are used for acid curable resin. Furan resin is furfuryl alcohol, furfuryl alcohol / urea formaldehyde resin, furfuryl alcohol / formaldehyde resin, furfuryl alcohol / phenol / formaldehyde. Resins and other known modified furan resins are used. Such a mold manufacturing method is capable of molding work with a high degree of freedom, and because it is excellent in the thermal properties of the mold, it can manufacture high-quality castings, so machine parts, construction machine parts, automobile parts, etc. It is widely used in casting of castings.

¡Improving the working environment during casting is an important item when casting a mold or casting a desired casting using a mold. Since acid-curable self-hardening molds use acids containing sulfur atoms such as organic sulfonic acid and sulfuric acid as curing agents, SOx such as sulfur dioxide and other pyrolysis gases such as sulfur dioxide at the time of casting have an effect on the working environment. There is a risk of worsening. For this reason, it is desired to suppress the generation of SOx (for example, JP-A-7-185732 and JP-A-2011-140034).

Further, a technique for reducing the generation of SO ₂ gas by a binder composition for mold making using a specific aromatic carboxylic acid having a hydroxyl group, and hardening for mold making using an oxycarboxylic acid having a carboxylic acid group as a curing agent. Agent compositions are also known (Japanese Patent Laid-Open No. 2012-148340 and Japanese Patent Laid-Open No. 11-90580).

Furthermore, the present applicant has also filed a patent application regarding a binder composition containing a furfural derivative and urea, and a mold-molding composition using dihydroxybenzoic acid and furfural in combination (Japanese Patent Laid-Open No. 2013-238881, And JP2013-240827A).

The mold molding composition of the present invention contains furfural, urea, and 2,6-dihydroxybenzoic acid, and the content of the furfural is 18.0 to 55.0% by mass.

Detailed Description of the Invention

As a method for improving the working environment at the time of casting, a method of reducing the amount of acid containing sulfur atoms is conceivable. However, in the conventional technology, if the amount of the acid containing sulfur atoms is reduced, the mold curing rate tends to decrease, so the time required for removing the mold from the original mold (molding time) becomes longer. , Mold productivity is reduced. For this reason, in the conventional technology, a certain amount or more of an acid containing sulfur atoms is used in order to suppress a decrease in the curing rate of the mold, so that SOx is generated depending on conditions, and the working environment is remarkably deteriorated due to the strong stimulating odor. there's a possibility that.

The present invention provides a mold-molding composition that can improve the curing rate of a mold without using an acid containing a sulfur atom as a curing agent component, and can solve the problem of deterioration of the working environment due to SOx. .

According to the present invention, there is provided a mold-molding composition that can improve the curing speed of a mold without using an acid containing a sulfur atom as a curing agent component, and can solve the problem of deterioration of the working environment due to SOx. Can be provided.

Hereinafter, an embodiment of the present invention will be described.

The mold molding composition of this embodiment is a mold molding composition containing furfural, urea, and 2,6-dihydroxybenzoic acid, and the content of the furfural is 18.0 to 55.0% by mass. is there. The mold molding composition can improve the mold curing rate without using a sulfur-containing acid, and has the effect of solving the problem of deterioration of the working environment due to SOx. The reason for such an effect is not clear, but is considered as follows.

Since the furfural in the composition has an aldehyde group, and the aldehyde group is highly reactive with the amide group of urea and the aromatic ring of phenols, furfural, urea, and 2,6-dihydroxybenzoic acid should be used simultaneously. It is considered that a three-dimensional crosslinking reaction occurs in the curing reaction process, and the curing rate of the mold is dramatically improved. Furthermore, among dihydroxybenzoic acids, 2,6 isomers have the lowest pKa among the isomers and have high catalytic ability, so that it is considered that the curing reaction is further accelerated. As a result, the mold curing rate can be improved without using an acid containing sulfur atoms, and the problem of deterioration of the working environment due to SOx can be solved.

Hereinafter, the mold making composition of this embodiment will be described.

<Mold molding composition>
[Furfural]
The furfural acts as a binder. The content of furfural in the mold molding composition is 18.0% by mass or more, preferably 20.0% by mass or more, and more preferably 24.0% by mass or more from the viewpoint of improving the curing rate of the mold. . From the same viewpoint, the content of furfural in the mold molding composition is 55.0% by mass or less, preferably 45.0% by mass or less, and more preferably 35.0% by mass or less. Further, from the same viewpoint, the content of furfural in the mold making composition is 18.0 to 55.0 mass%, preferably 20.0 to 45.0 mass%, and preferably 24.0 to 35. 0.0 mass% is more preferable.

〔urea〕
The urea content in the mold molding composition is preferably 0.50% by mass or more, more preferably 0.90% by mass or more, and even more preferably 1.50% by mass or more from the viewpoint of improving the curing rate of the mold. preferable. The content of urea in the mold molding composition is preferably 3.33% by mass or less, more preferably 2.67% by mass or less, from the viewpoint of the solubility of urea in the mold molding composition. More preferably, it is 35 mass% or less. In addition, the urea content in the mold molding composition is 0.50 to 3.33 mass% from the viewpoint of improving the curing rate of the mold and the solubility of urea in the mold molding composition. It is preferably 0.90 to 2.67% by mass, and more preferably 1.50 to 2.35% by mass.

[2,6-dihydroxybenzoic acid]
The content of 2,6-dihydroxybenzoic acid in the mold molding composition is preferably 13.3% by mass or more, more preferably 15.0% by mass or more, from the viewpoint of improving the curing rate of the mold. 7 mass% or more is still more preferable. From the same viewpoint, the content of 2,6-dihydroxybenzoic acid in the mold molding composition is preferably 35.0% by mass or less, more preferably 32.5% by mass or less, and 30.0% by mass or less. Is more preferable. Further, from the same viewpoint, the content of 2,6-dihydroxybenzoic acid in the mold making composition is preferably 13.3 to 35.0% by mass, more preferably 15.0 to 32.5% by mass. Preferably, 16.7 to 30.0% by mass is more preferable.

[Other ingredients]
[Acid curable resin]
The mold molding composition may contain a conventionally known acid curable resin as a binder component. Examples of the acid curable resin include furfuryl alcohol, condensate of furfuryl alcohol, condensate of furfuryl alcohol and aldehydes, condensate of furfuryl alcohol, urea and aldehydes (urea-modified furan resin), phenols, One consisting of one selected from the group consisting of condensates of aldehydes, condensates of melamine and aldehydes, and condensates of urea and aldehydes, and those consisting of a mixture of two or more selected from these groups It can be illustrated. Moreover, what consists of 2 or more types of cocondensates chosen from these groups can also be used. Of these, from the viewpoint of improving the mold curing speed and mold strength, it is selected from furfuryl alcohol, condensates of furfuryl alcohol, condensates of phenols and aldehydes, and condensates of furfuryl alcohol, urea and aldehydes. It is preferred to use one or more, as well as these cocondensates. Since furfuryl alcohol can be produced from a plant which is a non-petroleum resource, it is preferable to use furfuryl alcohol from the viewpoint of the global environment.

The content of the acid curable resin in the mold molding composition is preferably 5.0% by mass or more, and more preferably 10.0% by mass or more from the viewpoint of improving the mold strength. From the same viewpoint, the content of the acid curable resin in the binder composition is preferably 35.0% by mass or less, and more preferably 30.0% by mass or less. From the same viewpoint, the content of the acid curable resin in the mold molding composition is preferably 5.0 to 35.0% by mass, more preferably 10.0 to 30.0% by mass.

[Curing accelerator]
From the viewpoint of improving the final strength of the mold, the mold molding composition may contain a curing accelerator. As the curing accelerator, from the viewpoint of improving the final strength of the mold, a compound represented by the following general formula (1) (hereinafter referred to as curing accelerator (1)), a phenol derivative, an aromatic dialdehyde, and tannins One or more selected from the group consisting of

[Wherein, X ₁ and X ₂ each represent a hydrogen atom, CH ₃ or C ₂ H ₅ . ]

From the viewpoint of improving the final strength of the mold, the content of the curing accelerator in the mold making composition is preferably 0.2% by mass or more, more preferably 1.0% by mass or more, and 1.9% by mass. The above is more preferable. The content of the curing accelerator in the mold molding composition is preferably 35.0 mass% or less, preferably 35.0 mass% or less from the viewpoint of solubility of the curing accelerator and the final strength of the mold. Is more preferable, and 20.0 mass% or less is still more preferable.

Examples of the curing accelerator (1) include 2,5-bishydroxymethyl furan, 2,5-bismethoxymethyl furan, 2,5-bisethoxymethyl furan, 2-hydroxymethyl-5-methoxymethyl furan, 2- Examples thereof include hydroxymethyl-5-ethoxymethylfuran and 2-methoxymethyl-5-ethoxymethylfuran. Among these, 2,5-bishydroxymethylfuran is preferably used from the viewpoint of improving the final strength of the template.

Examples of the phenol derivative include resorcin, cresol, hydroquinone, phloroglucinol, and methylene bisphenol. Of these, resorcin is preferable from the viewpoint of the deep curability of the mold and the final strength of the mold.

Examples of the aromatic dialdehyde include terephthalaldehyde, phthalaldehyde and isophthalaldehyde, and derivatives thereof. These derivatives mean compounds having a substituent such as an alkyl group on the aromatic ring of an aromatic compound having two formyl groups as the basic skeleton. From the viewpoint of improving the final strength of the mold, terephthalaldehyde and terephthalaldehyde derivatives are preferred, and terephthalaldehyde is more preferred.

Examples of the tannins include condensed tannins and hydrolyzed tannins. Examples of these condensed tannins and hydrolyzed tannins include tannins having a pyrogallol skeleton and a resorcin skeleton. Moreover, you may add the extract from natural products, such as a leaf bark extract containing these tannins, and a leaf derived from a plant, a fruit, a seed | species, and a worm hump parasitic on a plant.

[water]
The mold molding composition may further contain water. For example, when synthesizing various condensates such as a condensate of furfuryl alcohol and aldehydes, an aqueous raw material is used or condensed water is generated. Therefore, the condensate is usually in the form of a mixture with water. It is obtained by. When such a condensate is used in the mold molding composition, water may be removed by topping or the like as necessary. However, as long as the curing reaction rate can be maintained, the water is intentionally removed during the production. There is no need. Further, water may be further added for the purpose of adjusting the viscosity of the mold making composition to an easy-to-handle viscosity. When water is further added for the purpose of adjusting the mold molding composition to an easy-to-handle viscosity, the content of water in the mold molding composition is preferably 0.5% by mass or more, and 1.5% by mass or more. Is more preferable, and 2.0 mass% or more is still more preferable. However, from the viewpoint of improving the mold curing rate, the content of water in the mold molding composition is preferably 6.7% by mass or less, more preferably 5.3% by mass or less, and 4.0% by mass or less. Further preferred. The water content in the mold making composition is 0.5 to 6.7% by mass from the viewpoint of adjusting the binder composition to a viscosity that is easy to handle and from the viewpoint of improving the mold curing rate. It is preferably 1.5 to 5.3% by mass, more preferably 2.0 to 4.0% by mass.

In the mold molding composition, an additive such as a silane coupling agent may be further contained. For example, it is preferable that a silane coupling agent is contained in the mold making composition because the final strength of the obtained mold can be further improved. Examples of silane coupling agents include N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl)- aminosilanes such as γ-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyldimethoxymethylsilane, Epoxy silanes such as 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, ureidosilane, mercaptosilane, sulfide silane, methacryloxysilane, acryloxysilane, and the like are used. Amino silane, epoxy silane, and ureido silane are preferable. More preferred are aminosilanes and epoxysilanes, and even more preferred are epoxysilanes. Of the epoxy silanes, 3-glycidoxypropyldimethoxymethylsilane is preferred. The content of the silane coupling agent in the mold molding composition is preferably 0.01% by mass or more, and more preferably 0.06% by mass or more from the viewpoint of improving the final strength of the mold. From the same viewpoint, the content of the silane coupling agent in the mold making composition is preferably 0.67% by mass or less, and more preferably 0.33% by mass or less. From the same viewpoint, the content of the silane coupling agent in the mold molding composition is preferably 0.01 to 0.67% by mass, and more preferably 0.06 to 0.33% by mass.

The mold molding composition may contain a known acidic substance as a curing agent component other than 2,6-dihydroxybenzoic acid so as not to inhibit the effect of the present embodiment. Examples of the acidic substance include one or a mixture of two or more of phosphoric acid compounds such as phosphoric acid or inorganic acids such as nitric acid. The content of the acidic substance in the mold making composition is preferably 2.50% by mass or more, more preferably 7.0% by mass or more, and more preferably 10.0% by mass or more from the viewpoint of improving the mold curing rate. Further preferred. From the same viewpoint, the content of the acidic substance in the mold making composition is preferably 30.0% by mass or less, more preferably 20.0% by mass or less, and further preferably 18.7% by mass or less. Further, from the same viewpoint, the content of the acidic substance in the mold making composition is preferably 2.50 to 30.0% by mass, more preferably 7.0 to 20.0% by mass, and 10. More preferably, 0 to 18.7% by mass.

Furthermore, the mold molding composition may contain one or more solvents selected from the group consisting of alcohols, ether alcohols and esters, and carboxylic acids other than 2,6-dihydroxybenzoic acid. . Among these, alcohols and ether alcohols are preferable and alcohols are more preferable from the viewpoint of improving the mold strength. The content of the solvent in the mold molding composition is preferably 7.0% by mass or more, more preferably 10.0% by mass or more from the viewpoint of improving the mold strength and dissolving the curing agent composition. 14.0 mass% or more is still more preferable. From the same viewpoint, the content of the solvent in the mold molding composition is preferably 28.0% by mass or less, more preferably 25.5% by mass or less, and further preferably 23.3% by mass or less. Further, from the same viewpoint, the content of the solvent in the mold making composition is preferably 7.0 to 28.0% by mass, more preferably 10.0 to 25.5% by mass, and 14.0. More preferred is ˜23.3 mass%. The content of the carboxylic acids in the mold making composition is preferably 1.75% by mass or more, and more preferably 3.50% by mass or more from the viewpoint of improving the mold strength. From the same viewpoint, the content of the carboxylic acids in the mold molding composition is preferably 14.0% by mass or less, and more preferably 11.5% by mass or less. Further, from the same viewpoint, the content of the carboxylic acids in the mold making composition is preferably 1.75 to 14.0% by mass, and more preferably 3.50 to 11.5% by mass.

From the viewpoint of improving the mold strength, the alcohols are preferably methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, and benzyl alcohol. The ether alcohols are ethylene glycol monoethyl ether, ethylene. Glycol monobutyl ether, ethylene glycol monohexyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, diethylene glycol monophenyl ether, ethylene glycol monophenyl ether are preferred, and esters include butyl acetate, butyl benzoate, ethylene Glycol monobutyl ether acetate, diethylene glycol Mono butyl ether acetate is preferable. As the carboxylic acids, an acid salt having a low pKa is preferable from the viewpoint of improving the template strength and reducing the odor. Oxalic acid, maleic acid, pyruvic acid, malonic acid, 2-furancarboxylic acid, phthalic acid, fumaric acid, lactic acid, citric acid Malic acid is more preferable, and oxalic acid and maleic acid are more preferable.

<Manufacturing method of self-hardening mold>
The manufacturing method of the self-hardening mold of the present embodiment includes a mixing step in which the mold-forming composition and the refractory particles are mixed to obtain a mold-making sand composition. “Mixing the mold-forming composition and refractory particles” according to the present embodiment means not only mixing the mold-forming composition and refractory particles prepared in advance, but also the furfural and urea. In addition, the above-mentioned 2,6-dihydroxybenzoic acid and the refractory particles are sequentially added and mixed.

(Fireproof particles)
As the refractory particles, conventionally known ones such as silica sand, chromite sand, zircon sand, olivine sand, alumina sand, mullite sand, synthetic mullite sand, etc. can be used. Recycled ones can also be used. Among these, it is preferable to contain silica sand.

In the said manufacturing method, although the quantity of the said composition for mold making can be set suitably, 0.5 mass part or more is preferable with respect to 100 mass parts of said refractory particles from a viewpoint of the hardening rate improvement of a casting_mold | template. 0 parts by mass or less is preferable. In the production method, the amount of the mold making composition is preferably 0.5 to 3.0 parts by mass with respect to 100 parts by mass of the refractory particles from the same viewpoint.

In the mixing step, the order of adding and mixing the furfural, the urea, the 2,6-dihydroxybenzoic acid, and the refractory particles according to the mold making composition is not particularly limited, and the previously prepared The mold molding composition and the refractory particles may be mixed, and the furfural, the urea, the 2,6-dihydroxybenzoic acid, and the refractory particles may be added and mixed, respectively. From the viewpoint of the productivity of the mold and the mold, a binder composition containing the furfural and the urea and a curing agent composition containing the 2,6-dihydroxybenzoic acid were prepared, respectively, and the refractory particles and the sticky composition were prepared. It is preferable to mix a binder composition and the curing agent composition to obtain a sand molding composition.

The ratio of the refractory particles, the binder composition, and the curing agent composition can be set as appropriate. From the viewpoint of improving the final strength of the mold, the binder is used with respect to 100 parts by mass of the refractory particles. The agent composition is preferably 0.5 parts by mass or more, and preferably 1.5 parts by mass or less with respect to 100 parts by mass of the refractory particles from the viewpoint of economy and improvement in casting quality. From the viewpoint of improving the final strength of the mold, the curing agent composition is preferably 0.07 parts by mass or more with respect to 100 parts by mass of the refractory particles, and from the viewpoint of economy and improvement in casting quality, the fire resistance 1.0 mass part or less is preferable with respect to 100 mass parts of conductive particles.

[Other ingredients]
In the mixing step, an acid curable resin, a curing accelerator, water, an additive such as a silane coupling agent, an acidic substance, a solvent, and a carboxylic acid may be added to the extent that the effects of the present embodiment are not impaired. . Acid curable resins, curing accelerators, water, additives such as silane coupling agents, acidic substances, solvents, and carboxylic acids can be used in the same amounts and amounts as in the mold molding composition.

In the mixing step, as a method of mixing the raw materials, a known general method can be used, for example, a method of adding each raw material by a batch mixer and kneading, or a method of supplying each raw material to a continuous mixer and kneading. The method of doing is mentioned.

In the self-hardening mold manufacturing method of the present embodiment, a mold can be manufactured by using a conventional mold manufacturing process as it is except for the mixing step. As a preferable method for producing a self-hardening mold, a mixing step of mixing the mold molding composition and refractory particles to obtain a mold molding sand composition, and filling the mold molding sand composition into a mold, The manufacturing method of the self-hardening casting_mold | template which has a hardening process which hardens the sand composition for mold making is mentioned.

<Self-hardening mold making kit>
The self-hardening mold making kit of this embodiment is a self-hardening mold making kit for producing the mold making composition comprising a binder composition and a curing agent composition, and the binder The composition contains furfural and urea, the curing agent composition contains 2,6-dihydroxybenzoic acid, and the content of the furfural in the binder composition is 35.0 to 90.0. % By mass.

[Binder composition]
The binder composition contains furfural and urea.

[Furfural]
The content of furfural in the binder composition is 35.0% by mass or more, preferably 40.0% by mass or more, and more preferably 42.5% by mass or more from the viewpoint of improving the curing rate of the mold. . From the same viewpoint, the content of furfural in the binder composition is 90.0% by mass or less, preferably 70.0% by mass or less, and more preferably 60.0% by mass or less. Further, from the same viewpoint, the content of furfural in the binder composition is 35.0 to 90.0% by mass, preferably 40.0 to 70.0% by mass, and 42.5 to 60.%. 0 mass% is more preferable.

[urea]
The content of urea in the binder composition is preferably 1.0% by mass or more, more preferably 1.3% by mass or more, and further preferably 1.6% by mass or more from the viewpoint of improving the curing rate of the mold. preferable. The content of urea in the binder composition is preferably 5.0% by mass or less, more preferably 4.5% by mass or less, from the viewpoint of solubility of urea in the mold making composition. 0 mass% or less is still more preferable. The urea content in the binder composition is 1.0 to 5.0% by mass from the viewpoint of improving the curing rate of the mold and from the viewpoint of the solubility of urea in the mold making composition. Preferably, the content is 1.3 to 4.5% by mass, more preferably 1.6 to 4.0% by mass.

[Other ingredients]
The remainder of the binder composition may contain additives such as an acid curable resin, a curing accelerator, water, and a silane coupling agent to the extent that the effects of the present embodiment are not impaired. As an acid curable resin, a curing accelerator, and a silane coupling agent that can be contained in the remainder of the binder composition, the acid curable resin that can be used in the mold molding composition, the curing accelerator, The same thing as the said silane coupling agent can be illustrated.

The content of the acid curable resin in the binder composition is preferably 15.0% by mass or more, and more preferably 25.0% by mass or more from the viewpoint of improving the mold strength. From the same viewpoint, the content of the acid curable resin in the binder composition is preferably 65.0% by mass or less, and more preferably 45.0% by mass or less. From the same viewpoint, the content of the acid curable resin in the binder composition is preferably 15.0 to 65.0 mass%, more preferably 25.0 to 55.0 mass%.

From the viewpoint of improving the final strength of the mold, the content of the curing accelerator in the binder composition is preferably 0.5% by mass or more, more preferably 1.8% by mass or more, and 3.0% by mass. % Or more is more preferable. The content of the curing accelerator in the binder composition is preferably 50.0% by mass or less from the viewpoint of solubility of the curing accelerator and the final strength of the mold, and is preferably 40.0% by mass. % Or less is more preferable, and 30.0 mass% or less is still more preferable.

The content of water in the binder composition is preferably 1.0% by mass or more, more preferably 3.0% by mass or more, from the viewpoint of adjusting the binder composition to a viscosity that is easy to handle. More preferably, the content is 0.0% by mass or more. However, from the viewpoint of improving the curing rate of the mold, the content of water in the binder composition is preferably 10.0% by mass or less, more preferably 8.0% by mass or less, and 6.0% by mass or less. Further preferred. The water content in the binder composition is 1.0 to 10.0% by mass from the viewpoint of adjusting the binder composition to a viscosity that is easy to handle and from the viewpoint of improving the curing rate of the mold. It is preferably 3.0 to 8.0% by mass, more preferably 4.0 to 6.0% by mass.

From the viewpoint of improving the final strength of the mold, the content of the silane coupling agent in the binder composition is preferably 0.01% by mass or more, and more preferably 0.05% by mass or more. From the same viewpoint, the content of the silane coupling agent in the binder composition is preferably 1.0% by mass or less, and more preferably 0.5% by mass or less.

[Curing agent composition]
The curing agent composition contains 2,6-dihydroxybenzoic acid.

[2,6-dihydroxybenzoic acid]
The content of 2,6-dihydroxybenzoic acid in the curing agent composition is preferably 40.0% by mass or more, and more preferably 45.0% by mass or more from the viewpoint of improving the curing rate of the mold. From the same viewpoint, the content of 2,6-dihydroxybenzoic acid in the curing agent composition is preferably 70.0% by mass or less, and more preferably 65.5% by mass or less. In addition, the content of 2,6-dihydroxybenzoic acid in the curing agent composition is preferably 40.0 to 70.0% by mass, more preferably 45.0 to 65.5% by mass, from the same viewpoint.

[Other ingredients]
The curing agent composition may contain a known acidic substance as a curing agent component other than 2,6-dihydroxybenzoic acid to the extent that the effects of the present embodiment are not impaired. Examples of the acidic substance include the acidic substance that can be used for the mold making composition.

The content of the acidic substance in the curing agent composition is preferably 10.0% by mass or more, more preferably 20.0% by mass or more, and further preferably 30.0% by mass or more from the viewpoint of improving the mold curing rate. preferable. From the same viewpoint, the content of the acidic substance in the curing agent composition is preferably 50.0% by mass or less, more preferably 45.0% by mass or less, and still more preferably 40.0% by mass or less. Further, from the same viewpoint, the content of the acidic substance in the curing agent composition is preferably 10.0 to 50.0% by mass, more preferably 20.0 to 45.0% by mass, and 30.0%. More preferably, it is 40.0% by mass.

Furthermore, the curing agent composition may contain one or more solvents selected from the group consisting of alcohols, ether alcohols, and esters and carboxylic acids to the extent that the effects of the present embodiment are not impaired. . Examples of the solvent and the carboxylic acids include the solvent that can be used in the mold molding composition and the carboxylic acids.

The content of the solvent in the curing agent composition is preferably 20.0% by mass or more, more preferably 30.0% by mass or more, from the viewpoint of improving the mold strength and dissolving the curing agent composition. More preferably, the content is 0.0% by mass or more. From the same viewpoint, the content of the solvent in the curing agent composition is preferably 60.0% by mass or less, more preferably 55.0% by mass or less, and further preferably 50.0% by mass or less. Further, from the same viewpoint, the content of the solvent in the curing agent composition is preferably 20.0 to 60.0% by mass, more preferably 30.0 to 55.0% by mass, and 40.0 to 50.0 mass% is still more preferable. The content of the carboxylic acids in the curing agent composition is preferably 5.0% by mass or more, and more preferably 10.0% by mass or more from the viewpoint of improving the mold strength. From the same viewpoint, the content of the carboxylic acids in the curing agent composition is preferably 30.0% by mass or less, and more preferably 25.0% by mass or less. In addition, the content of the carboxylic acids in the curing agent composition is preferably 5.0 to 30.0% by mass, and more preferably 10.0 to 25.0% by mass from the same viewpoint.

Regarding the embodiment described above, the present invention further discloses the following composition, production method, or use.

<1> A mold making composition containing furfural, urea, and 2,6-dihydroxybenzoic acid, wherein the content of furfural is 18.0 to 55.0% by mass.
<2> The content of furfural in the mold making composition is preferably 18.0% by mass or more, more preferably 20.0% by mass or more, further preferably 24.0% by mass or more, and 55.0% by mass. % Or less is preferable, 45.0% by mass or less is more preferable, 35.0% by mass or less is further preferable, 18.0 to 55.0% by mass is preferable, and 20.0 to 45.0% by mass is more preferable. The composition for molding a mold according to <1>, wherein 24.0 to 35.0% by mass is more preferable.
<3> The content of urea in the mold making composition is preferably 0.50% by mass or more, more preferably 0.90% by mass or more, still more preferably 1.50% by mass or more, and 3.33% by mass. % Or less, preferably 2.67% by mass or less, more preferably 2.35% by mass or less, further preferably 0.50 to 3.33% by mass, more preferably 0.90 to 2.67% by mass, The mold molding composition as described in <1> or <2>, wherein 1.50 to 2.35% by mass is more preferable.
<4> The content of 2,6-dihydroxybenzoic acid in the mold molding composition is preferably 13.3 mass% or more, more preferably 15.0 mass% or more, and further 16.7 mass% or more. Preferably, 35.0% by mass or less is preferable, 32.5% by mass or less is more preferable, 30.0% by mass or less is more preferable, 13.3 to 35.0% by mass is preferable, and 15.0 to 32.5% is preferable. The composition for mold making according to any one of <1> to <3>, wherein the composition is more preferably% by mass, and further preferably 16.7 to 30.0% by mass.
<5> The mold molding composition according to any one of <1> to <4>, wherein the mold molding composition preferably contains an acid curable resin.
<6> The content of the acid curable resin in the mold molding composition is preferably 5.0% by mass or more, more preferably 10.0% by mass or more, and preferably 35.0% by mass or less, 30 The molding composition according to the above <5>, more preferably 0.0% by mass or less, more preferably 5.0 to 35.0% by mass, and even more preferably 10.0 to 30.0% by mass.
<7> The mold making composition according to any one of <1> to <6>, further comprising a curing accelerator.
<8> Said curing accelerator is at least one selected from the group consisting of curing accelerator (1) represented by general formula (1), phenol derivative, aromatic dialdehyde, and tannins <7> The molding composition.
<9> The content of the curing accelerator in the mold molding composition is preferably 0.2% by mass or more, more preferably 1.0% by mass or more, still more preferably 1.9% by mass or more, 35.0 % By mass or less, preferably 30.0% by mass or less, more preferably 20.0% by mass or less, further preferably 0.2 to 35% by mass, more preferably 1.0 to 30.0% by mass. The composition for mold making according to <7> or <8>, wherein 9 to 20.0% by mass is more preferable.
<10> The curing accelerator (1) is 2,5-bis (hydroxymethyl) furan, 2,5-bis (methoxymethyl) furan, 2,5-bis (ethoxymethyl) furan, 2-hydroxymethyl- One or more selected from the group consisting of 5-methoxymethylfuran, 2-hydroxymethyl-5-ethoxymethylfuran, 2-methoxymethyl-5-ethoxymethylfuran is preferred, and 2,5-bis (hydroxymethyl) furan is preferred. More preferable composition for mold making according to the above <8> or <9>.
<11> The template according to any one of <8> to <10>, wherein the aromatic dialdehyde is preferably one or more selected from the group consisting of terephthalaldehyde, phthalaldehyde, isophthalaldehyde, and the like, and derivatives thereof. Molding composition.
<12> The content of water in the mold molding composition is preferably 0.5% by mass or more, more preferably 1.5% by mass or more, still more preferably 2.0% by mass or more, and 6.7% by mass. % Or less, preferably 5.3% by mass or less, more preferably 4.0% by mass or less, further preferably 0.5 to 6.7% by mass, more preferably 1.5 to 5.3% by mass, The molding composition according to any one of <1> to <11>, wherein 2.0 to 4.0% by mass is more preferable.
<13> The mold making composition according to any one of <1> to <12>, further comprising a silane coupling agent.
<14> The content of the silane coupling agent in the mold making composition is preferably 0.01% by mass or more, more preferably 0.06% by mass or more, and preferably 0.67% by mass or less. Preferably, it is 0.33 mass% or less, preferably 0.01 to 0.67 mass%, more preferably 0.06 to 0.33 mass%, <13> object.
<15> The composition for molding a mold according to <13> or <14>, wherein the silane coupling agent is preferably 3-glycidoxypropyldimethoxymethylsilane.
<16> Further, an acidic substance is contained as a curing agent component other than 2,6-dihydroxybenzoic acid, and the content of the acidic substance in the mold molding composition is preferably 2.50% by mass or more, 0.0 mass% or more is more preferable, 10.0 mass% or more is further preferable, 30.0 mass% or less is preferable, 20.0 mass% or less is more preferable, 18.7 mass% or less is further preferable, and 2. 50 to 30.0% by mass is preferable, 7.0 to 20.0% by mass is more preferable, and 10.0 to 18.7% by mass is further preferable, according to any one of <1> to <15> above. Mold molding composition.
<17> Further, a solvent is contained, and the content of the solvent in the mold making composition is preferably 7.0% by mass or more, more preferably 10.0% by mass or more, and 14.0% by mass or more. Is more preferably 28.0% by mass or less, more preferably 25.5% by mass or less, further preferably 23.3% by mass or less, preferably 7.0 to 28.0% by mass, or 10.0 to 25%. The composition for mold making according to any one of <1> to <16>, more preferably 0.5% by mass, and still more preferably 14.0 to 23.3% by mass.
<18> Further, a carboxylic acid other than 2,6-dihydroxybenzoic acid is contained, and the content of the carboxylic acid in the mold molding composition is preferably 1.75% by mass or more, and 3.50% by mass. The above is more preferable, 14.0% by mass or less is preferable, 11.5% by mass or less is more preferable, 1.75 to 14.0% by mass is preferable, and 3.50 to 11.5% by mass is more preferable. <1>-<17> The composition for mold making according to any one of <1> to <17>.
<19> A method for producing a self-hardening mold, comprising a mixing step of mixing the mold-forming composition according to any one of the above <1> to <18> and the refractory particles to obtain a mold-forming sand composition.
<20> The amount of the mold making composition is preferably 0.5 parts by mass or more, preferably 3.0 parts by mass or less, and 100 parts by mass of the refractory particles with respect to 100 parts by mass of the refractory particles. On the other hand, the method for producing a self-hardening mold according to <19>, wherein 0.5 to 3.0 parts by mass is preferable.
<21> The mixing step prepares a binder composition containing the furfural and the urea, and a curing agent composition containing the 2,6-dihydroxybenzoic acid, respectively, and the refractory particles, the binder The method for producing a self-hardening mold according to the above <19> or <20>, wherein it is preferable to mix an agent composition and the curing agent composition to obtain a sand molding molding composition.
<22> The ratio of the refractory particles, the binder composition, and the curing agent composition is 0.5 parts by mass or more with respect to 100 parts by mass of the refractory particles. Preferably, 1.5 parts by mass or less is preferable, and the curing agent composition is preferably 0.07 parts by mass or more, and preferably 1.0 parts by mass or less, based on 100 parts by mass of the refractory particles, <19 The method for producing a self-hardening mold according to any one of> to <21>.
<23> A mixing step of mixing the mold molding composition and refractory particles to obtain a mold molding sand composition, and filling the mold molding sand composition in a mold, the mold molding sand composition The method for producing a self-hardening mold according to any one of the above items <19> to <22>, preferably including a curing step of curing the resin.
<24> A self-hardening mold making kit for producing the mold making composition according to any one of <1> to <18>, which comprises a binder composition and a curing agent composition, The binder composition contains furfural and urea, the curing agent composition contains 2,6-dihydroxybenzoic acid, and the content of the furfural in the binder composition is 35.0 to A self-hardening mold making kit of 90.0% by mass.
<25> The content of furfural in the binder composition is preferably 35.0% by mass or more, more preferably 40.0% by mass or more, still more preferably 42.5% by mass or more, and 90.0% by mass. % Or less, more preferably 70.0% by mass or less, further preferably 60.0% by mass or less, more preferably 35.0 to 90.0% by mass, more preferably 40.0 to 70.0% by mass, The self-hardening mold making kit according to <24>, further preferably 42.5 to 60.0% by mass.
<26> The content of urea in the binder composition is preferably 1.0% by mass or more, more preferably 1.3% by mass or more, still more preferably 1.6% by mass or more, and 5.0% by mass. % Or less, more preferably 4.5% by mass or less, still more preferably 4.0% by mass or less, 1.0 to 5.0% by mass, and preferably 1.3 to 4.5% by mass. The self-hardening mold making kit according to <24> or <25>, more preferably from 6 to 4.0% by mass.
<27> The self-hardening mold making kit according to any one of <24> to <26>, wherein the binder composition preferably contains an acid curable resin.
<28> The content of the acid curable resin in the binder composition is preferably 15.0% by mass or more, more preferably 25.0% by mass or more, and preferably 65.0% by mass or less, 45 Self-hardening according to any one of <24> to <27>, more preferably 0.0% by mass or less, more preferably 15.0 to 65.0% by mass, and more preferably 25.0 to 45.0% by mass. Mold making kit.
<29> The self-hardening mold making kit according to any one of <24> to <28>, wherein the binder composition further contains a curing accelerator.
<30> The curing accelerator is at least one selected from the group consisting of the curing accelerator (1) represented by the general formula (1), a phenol derivative, an aromatic dialdehyde, and tannins. 29>, a self-hardening mold making kit.
<31> The content of the curing accelerator in the binder composition is preferably 0.5% by mass or more, more preferably 1.8% by mass or more, further preferably 3.0% by mass or more, 50 The self-hardening mold making kit according to <29> or <30>, preferably 0.0% by mass or less, more preferably 40.0% by mass or less, and still more preferably 30.0% by mass or less.
<32> The binder composition further contains water, and the water content in the binder composition is preferably 1.0% by mass or more, more preferably 3.0% by mass or more. 4.0% by mass or more is more preferable, 10.0% by mass or less is preferable, 8.0% by mass or less is more preferable, 6.0% by mass or less is further preferable, and 1.0 to 10.0% by mass is preferable. The self-hardening mold making kit according to any one of <24> to <31>, preferably 3.0 to 8.0% by mass, more preferably 4.0 to 6.0% by mass.
<33> The binder composition further contains a silane coupling agent, and the content of the silane coupling agent in the binder composition is preferably 0.01% by mass or more, 0.05 The self-hardening mold making kit according to any one of <24> to <32>, wherein the kit is more preferably at least mass%, preferably at most 1.0 mass%, more preferably at most 0.5 mass%.
<34> The content of 2,6-dihydroxybenzoic acid in the curing agent composition is preferably 40.0% by mass or more, more preferably 45.0% by mass or more, and preferably 70.0% by mass or less. 65.5% by mass or less is more preferable, 40.0 to 70.0% by mass is preferable, and 45.0 to 65.5% by mass is more preferable. Hard mold making kit.
<35> The curing agent composition further contains the acidic substance, and the content of the acidic substance in the curing agent composition is preferably 10.0% by mass or more, and more preferably 20.0% by mass or more. More preferably, 30.0% by mass or more is more preferable, 50.0% by mass or less is preferable, 45.0% by mass or less is more preferable, 40.0% by mass or less is further preferable, and 10.0 to 50.0% by mass. %, 20.0 to 45.0% by mass is more preferable, and 30.0 to 40.0% by mass is more preferable. Self-hardening mold making kit according to any one of the above <24> to <34><36> The curing agent composition further contains a solvent, and the content of the solvent in the curing agent composition is preferably 20.0 mass% or more, more preferably 30.0 mass% or more, More preferably 40.0% by mass or more, 60.0% % Or less is preferable, 55.0% by mass or less is more preferable, 50.0% by mass or less is further preferable, 20.0 to 60.0% by mass is preferable, and 30.0 to 55.0% by mass is more preferable. The self-hardening mold making kit according to any one of <24> to <35>, further preferably 40.0 to 50.0% by mass.
<37> The curing agent composition further contains the carboxylic acids, and the content of the carboxylic acids in the curing agent composition is preferably 5.0% by mass or more, and 10.0% by mass or more. More preferably, 30.0% by mass or less is preferable, 25.0% by mass or less is more preferable, 5.0 to 30.0% by mass is preferable, and 10.0 to 25.0% by mass is more preferable. <24 The self-hardening mold making kit according to any one of> to <36>.

Hereinafter, examples and the like specifically showing the present invention will be described.

<Urea-modified furan resin>
In a three-necked flask, 100 parts by mass of furfuryl alcohol, 35 parts by mass of paraformaldehyde, and 13 parts by mass of urea were mixed and adjusted to pH 9 with a 25% by mass aqueous sodium hydroxide solution. The reaction mixture was heated to 100 ° C. and reacted at the same temperature for 1 hour. The pH was adjusted to 4.5 with 37% by mass hydrochloric acid, and the mixture was further reacted at 100 ° C. for 1 hour. Thereafter, the pH was adjusted to 7 with a 25% by mass aqueous sodium hydroxide solution, 5 parts by mass of urea was added, and the mixture was reacted at 100 ° C. for 30 minutes to obtain a urea-modified furan resin (unreacted furfuryl in the reaction product). The product excluding alcohol and water is referred to as urea-modified furan resin).

<Examples 1 to 6, Comparative Examples 1 to 11>
[Production example of sand composition for mold making]
An acid curable resin, an aldehyde compound, urea or a derivative thereof, water, a silane coupling agent, an acid, and methanol shown in Table 1 are mixed in the composition shown in Table 1, and a binder composition and a curing agent composition are mixed. Got. Under conditions of 25 ° C. and 55% RH, 0.70 parts by mass of the curing agent composition according to each example and comparative example shown in Table 1 is added to 100 parts by mass of silica sand (free mantle fresh sand), and then 1.00 parts by mass of the binder composition according to each Example and Comparative Example shown in 1 was added, and these were mixed to obtain a sand mold molding composition (kneaded sand). In Table 1, FFA means furfuryl alcohol, and 3-glycidoxypropyldimethoxymethylsilane (manufactured by Shin-Etsu Chemical Co., Ltd.) was used as the silane coupling agent.

[Measurement of curing speed and final strength]
The obtained molding sand composition (kneaded sand) was filled into a cylindrical test piece frame having a diameter of 50 mm and a height of 50 mm, and after 0.5 hours, the mold was removed, and it was described in JIS Z 2604-1976. The compressive strength (MPa) of the test piece was measured by the above method. In addition, a test piece frame separately prepared in the same manner was removed when 0.5 hour and 1 hour had elapsed, and the compressive strength (MPa) of the test piece was measured by the same method. The higher the “compressive strength after 0.5 hour” and the “compressive strength after 1 hour”, the faster the curing rate. In addition, when a test piece frame prepared in the same manner is filled in two hours, the mold is removed, and after 22 hours, that is, 24 hours after filling the test piece frame, The compressive strength (compressive strength after 24 hours (MPa)) was measured. The higher the “compressive strength after 24 hours”, the higher the final strength of the mold.

Table 1 shows the results of each example and comparative example.

Claims

A mold molding composition containing furfural, urea, and 2,6-dihydroxybenzoic acid, wherein the content of the furfural is 18.0 to 55.0% by mass.
2. The mold making composition according to claim 1, wherein the urea content is 0.5 to 3.33 mass%.
3. The mold making composition according to claim 1, wherein the content of 2,6-dihydroxybenzoic acid is 13.3 to 35.0 mass%.
A method for producing a self-hardening mold comprising a mixing step of mixing the mold-forming composition according to any one of claims 1 to 3 with refractory particles to obtain a mold-forming sand composition.
A self-hardening mold making kit for producing the mold making composition according to any one of claims 1 to 3, comprising a binder composition and a curing agent composition,
The binder composition contains furfural and urea;
The curing agent composition contains 2,6-dihydroxybenzoic acid;
A self-hardening mold making kit, wherein the content of the furfural in the binder composition is 35.0 to 90.0 mass%.
The self-hardening mold making kit according to claim 5, wherein the content of urea in the binder composition is 1.0 to 5.0 mass%.
The self-hardening mold making kit according to claim 5 or 6, wherein a content of the 2,6-dihydroxybenzoic acid in the curing agent composition is 40.0 to 70.0 mass%.