CN112203784A - Binder composition for mold making - Google Patents
Binder composition for mold making Download PDFInfo
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- CN112203784A CN112203784A CN201880093796.6A CN201880093796A CN112203784A CN 112203784 A CN112203784 A CN 112203784A CN 201880093796 A CN201880093796 A CN 201880093796A CN 112203784 A CN112203784 A CN 112203784A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
- B22C1/02—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by additives for special purposes, e.g. indicators, breakdown additives
- B22C1/10—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by additives for special purposes, e.g. indicators, breakdown additives for influencing the hardening tendency of the mould material
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
- B22C1/16—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents
- B22C1/20—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents of organic agents
- B22C1/22—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents of organic agents of resins or rosins
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Abstract
The binder composition for mold making of the present invention comprises a furan resin, water, and a hydrolyzed starch, wherein the mass ratio of the furan resin to the hydrolyzed starch (mass of the furan resin/mass of the hydrolyzed starch) is 20 to 95, and the dextrose equivalent of the hydrolyzed starch is 60 or more. According to the binder composition for mold making of the present invention, it is possible to provide a binder composition for mold making that uses a saccharide without a modification step and can suppress economic cost and energy cost.
Description
Technical Field
The present invention relates to a binder composition for mold making.
Background
Generally, an acid-curable mold is manufactured as follows: adding to refractory particles such as silica sand: the binder composition for mold making containing an acid-curable resin and the curing agent composition containing sulfonic acid, sulfuric acid, phosphoric acid and the like are kneaded, and the resulting kneaded sand is filled into a prototype such as a wood mold to cure the acid-curable resin. As the acid-curable resin, furan resin, phenol resin, or the like is used, and as the furan resin, furfuryl alcohol-urea-formaldehyde resin, furfuryl alcohol-phenol-formaldehyde resin, other known modified furan resins, or the like is used. Such a method for producing a mold is widely used for casting a casting such as a machine part, a construction machine part, or an automobile part because it enables a high-quality casting to be produced by a high-degree-of-freedom molding operation and because it has excellent thermal properties.
As described above, furfuryl alcohol is widely used as a constituent component of an acid-curable resin such as a furan resin. However, furfuryl alcohol is subjected to a step of hydrolyzing and dehydrating a raw material consisting of agricultural byproducts such as corn cob to obtain furfural; then, furfural is produced through the step of hydrogenation, which increases the production cost. In addition, a large amount of residue is generated as waste in the furfural production process (chinese patent application publication No. 103113548). In recent years, furfuryl alcohol and furfural production plants have been unable to stably supply furfuryl alcohol due to reasons such as shutdown due to environmental regulations and production reduction. From the above background, an alternative raw material to furfuryl alcohol, which is inexpensive, has a low load on the environment, and has high supply stability, is required.
Examples of the inexpensive reagent having a low load on the environment and high supply stability include saccharides, and a method for producing a furan resin in which a part of furfuryl alcohol is replaced with a saccharide has been reported (specification of chinese patent application No. 102861867).
Disclosure of Invention
The binder composition for mold making of the present invention comprises a furan resin, water, and a hydrolyzed starch, wherein the mass ratio of the furan resin to the hydrolyzed starch (mass of the furan resin/mass of the hydrolyzed starch) is 20 to 95, and the dextrose equivalent of the hydrolyzed starch is 60 or more.
Detailed Description
Since the solubility of saccharides to furan resins is poor, it has been necessary to improve the solubility to furan resins by modification by reaction with furan resins or the like. However, this modification requires a complicated process, and requires economic and energy costs.
The invention provides a binder composition for mold making, which uses saccharides without modification process and can restrain economic cost and energy cost.
The binder composition for mold making of the present invention comprises a furan resin, water, and a hydrolyzed starch, wherein the mass ratio of the furan resin to the hydrolyzed starch (mass of the furan resin/mass of the hydrolyzed starch) is 20 to 95, and the dextrose equivalent of the hydrolyzed starch is 60 or more.
According to the present invention, there can be provided a binder composition for mold making, which can suppress economic cost and energy cost by using a saccharide without requiring a modification step.
Hereinafter, one embodiment of the present invention will be described.
< Binder composition for mold formation >
The binder composition for mold making according to the present embodiment (hereinafter, also simply referred to as a binder composition) contains a furan resin, water, and a hydrolyzed starch, wherein the mass ratio of the furan resin to the hydrolyzed starch (mass of the furan resin/mass of the hydrolyzed starch) is 20 to 95, and the dextrose equivalent of the hydrolyzed starch is 60 or more.
According to the binder composition of the present embodiment, the use of saccharides eliminates the need for a modification step and can suppress economic and energy costs. The reason why the adhesive composition of the present embodiment exerts such an effect is not determined, but the following is considered.
Although starch tends to have poor solubility in furan resin, it has been found that by using hydrolyzed starch having a specific dextrose equivalent (DE equivalent) and setting the mass ratio of furan resin to hydrolyzed starch (mass of the furan resin/mass of the hydrolyzed starch) within a specific range, it is possible to obtain solubility in both water and furan resin of at least a certain level. Therefore, if the mass ratio of the furan resin to the hydrolyzed starch is set to a specific range, the solubility in the furan resin can be improved, and therefore, there is no need to modify the saccharide in particular, and the saccharide is not separated from the furan resin component and the like and can be maintained in a uniform state even after the binder composition is prepared and left for a long time. Therefore, according to the binder composition of the present embodiment, it is considered that the use of saccharides does not require a modification step and can suppress economic cost and energy cost. Further, it is considered that the binder composition does not phase separate in the step of kneading with the curing agent composition and the refractory particles, and can form a uniform adhesive layer, and thus can maintain the mold strength.
[ Furan resin ]
Examples of the furan resin include 1 type selected from furfuryl alcohol, a condensate of furfuryl alcohol and an aldehyde, a condensate of furfuryl alcohol and urea and an aldehyde (urea-modified furan resin), a condensate of urea and ethylene urea and an aldehyde (urea-ethylene urea copolycondensation resin), a condensate of melamine and an aldehyde, and a condensate of urea and an aldehyde; a substance formed of a mixture of 2 or more selected from these. In addition, a copolycondensate containing 2 or more kinds selected from these may be used. Among them, from the viewpoint of improving the solidification rate of the mold and improving the mold strength, it is preferable to use 1 or more selected from furfuryl alcohol, a condensate of furfuryl alcohol, and a condensate of furfuryl alcohol, urea, and aldehydes, and a copolycondensate thereof.
The monomer composition used for the synthesis of the furan resin contains furfuryl alcohol, and 1 or more monomers selected from aldehydes, urea, phenols, and melamine, for example, can be selected and used depending on the target condensate.
Examples of the aldehydes include formaldehyde, acetaldehyde, glyoxal, furfural, terephthalaldehyde, hydroxymethylfurfural, and the like, and 1 or more of these can be suitably used. From the viewpoint of improving the mold strength, formaldehyde is preferably used, and from the viewpoint of reducing the amount of formaldehyde generated during molding, furfural, terephthalaldehyde, and hydroxymethylfurfural are preferably used.
Examples of the phenols include phenol, cresol, resorcinol, bisphenol a, bisphenol C, bisphenol E, bisphenol F, and the like, and 1 or more of these can be used.
In the case of producing a condensate of furfuryl alcohol and an aldehyde, it is preferable to use 0.01 to 1 mole of the aldehyde based on 1 mole of furfuryl alcohol. In the case of producing a condensate of furfuryl alcohol with aldehydes and urea, it is preferable to use 0.05 to 3 moles of aldehydes and 0.03 to 1.5 moles of urea per 1 mole of furfuryl alcohol.
The reaction temperature in synthesizing the furan resin varies depending on the raw material used, and is preferably 50 to 150 ℃, more preferably 70 to 130 ℃, and further preferably 80 to 130 ℃ from the viewpoints of viscosity of the obtained binder composition, residual aldehyde content, reduction in production time, prevention of runaway reaction of the furan resin, and prevention of evaporation of the raw material. From the same viewpoint, the reaction time in the synthesis of the furan resin is preferably 0.5 to 12 hours, more preferably 1 to 10 hours, and still more preferably 3 to 8 hours.
In the production of furan resins, furfuryl alcohol as a raw material, water contained in the raw material, water produced during the reaction, and the like may be contained and may not be removed from the viewpoint of economy. The furan resin composition contains a furan resin, furfuryl alcohol, and a component other than the furan resin, for example, water.
The content of the furan resin in the binder composition is preferably 50% by mass or more, more preferably 60% by mass or more, and further preferably 65% by mass or more, from the viewpoint of improvement in mold strength. The content of the furan resin in the binder composition is more preferably 98% by mass or less, and still more preferably 95% by mass or less, from the viewpoint of lowering the viscosity. The content of the furan resin in the binder composition of the present embodiment is preferably 50 to 98 mass%, more preferably 60 to 95 mass%, and still more preferably 65 to 95 mass%, from the viewpoint of improvement in mold strength and reduction in viscosity.
[ Water ]
The content of water in the adhesive composition is preferably 0.5% by mass or more, more preferably 1% by mass or more, and still more preferably 3% by mass or more. However, the water content of the binder composition is preferably 30% by mass or less, more preferably 25% by mass or less, from the viewpoint of maintaining the curing reaction rate. From the viewpoint of adjusting the viscosity of the binder composition to a viscosity that is easy to handle and from the viewpoint of maintaining the curing reaction rate, the water content of the binder composition is preferably 0.5 to 30% by mass, more preferably 1 to 25% by mass, and still more preferably 3 to 25% by mass.
In the case of synthesizing various condensates such as a condensate of furfuryl alcohol and an aldehyde, since a raw material in an aqueous solution state is used or condensation water is generated, the condensate is usually obtained in the form of a mixture with water. When such a condensate is used in the binder composition, water may be removed by a distillation apparatus or the like as necessary, but as long as the curing reaction rate can be maintained, it is not necessary to remove the condensate during production.
[ hydrolyzed starch ]
The hydrolyzed starch is obtained by hydrolyzing starch with an acid, an enzyme, or the like. The hydrolyzed starch has a dextrose equivalent of 60 or more, preferably 70 or more, from the viewpoint of compatibility with the furan resin. From the viewpoint of economy, the hydrolyzed starch preferably has a dextrose equivalent of 99 or less, more preferably 80 or less. The glucose Equivalent is also referred to as a glucose Equivalent value (Dextrose Equivalent value) and is used as an index of the degree of decomposition of a starch decomposition product by measuring a reducing sugar as glucose and expressing a ratio of the reducing sugar to the total solid content of the reducing sugar. In the present specification, the glucose equivalent is measured by the method described in the examples.
As the above hydrolyzed starch, for example, Fuji Syrup (trade name) (garneta chemical) and the like are available as a commercially available product.
From the viewpoint of compatibility between the hydrolyzed starch and the furan resin, the mass ratio of the furan resin to the hydrolyzed starch (mass of the furan resin/mass of the hydrolyzed starch) is 20 to 95, preferably 70 to 90.
From the viewpoint of compatibility of the hydrolyzed starch with water, and from the viewpoint of compatibility with water, the mass ratio of water to the hydrolyzed starch (mass of water/mass of the hydrolyzed starch) is 1 to 30, preferably 2 to 20.
From the viewpoint of economy, the content of the hydrolyzed starch is preferably 1% by mass or more, and more preferably 2% by mass or more. The content of the hydrolyzed starch is preferably 20% by mass or less, and more preferably 10% by mass or less, from the viewpoint of compatibility of the hydrolyzed starch with the furan resin and the viewpoint of mold strength. The content of the hydrolyzed starch is preferably 1 to 20% by mass, more preferably 2 to 10% by mass, from the viewpoint of economy, compatibility of the hydrolyzed starch with the furan resin, and mold strength.
[ curing accelerators ]
The binder composition of the present embodiment may contain a curing accelerator from the viewpoint of preventing cracking of the mold and from the viewpoint of improving the final mold strength. The curing accelerator is preferably 1 or more selected from the group consisting of compounds represented by the following general formula (1) (hereinafter, referred to as curing accelerators (1)), phenol derivatives, aromatic dialdehydes, and tannins, from the viewpoint of improving the final mold strength.
[ chemical formula 1]
[ in the formula, X1And X2Each represents a hydrogen atom, CH3Or C2H5Any one of (1). Angle (c)
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, even more preferably 2.5% by mass or more, and even more preferably 3.0% by mass or more, from the viewpoint of improving the final strength of the mold. The content of the curing accelerator in the binder composition is preferably 63 mass% or less, more preferably 50 mass% or less, and even more preferably 40 mass% or less, from the viewpoint of solubility of the curing accelerator in furan resin and the viewpoint of improving the final strength of the mold.
Examples of the curing accelerator (1) include 2, 5-bis-hydroxymethylfuran, 2, 5-bis-methoxymethylfuran, 2, 5-bis-ethoxymethylfuran, 2-hydroxymethyl-5-methoxymethylfuran, 2-hydroxymethyl-5-ethoxymethylfuran, and 2-methoxymethyl-5-ethoxymethylfuran. Among them, 2, 5-bis (hydroxymethyl) furan is preferably used from the viewpoint of improving the final mold strength.
Examples of the phenol derivative include resorcinol, cresol, hydroquinone, phloroglucinol, and methylene bisphenol. Among them, resorcinol is preferable from the viewpoint of deep curing of the mold and the viewpoint of improving the final mold strength. The content of the phenol derivative in the binder composition is preferably 1 to 25% by mass, more preferably 2 to 15% by mass, and even more preferably 3 to 10% by mass, from the viewpoint of solubility of the phenol derivative in the furan resin and from the viewpoint of improvement of the final mold strength. Among these, when resorcinol is used, the content of resorcinol in the adhesive composition is preferably 1 to 10% by mass, more preferably 2 to 7% by mass, and even more preferably 3 to 6% by mass, from the viewpoint of solubility of resorcinol in furan resin and from the viewpoint of improvement in final mold strength.
Examples of the aromatic dialdehyde include terephthalaldehyde, o-phthalaldehyde, m-phthalaldehyde, and derivatives thereof. The derivatives thereof include compounds having a substituent such as an alkyl group on the aromatic ring of an aromatic compound having 2 formyl groups as a basic skeleton. From the viewpoint of preventing mold cracking, terephthalaldehyde and derivatives of terephthalaldehyde are preferable, and terephthalaldehyde is more preferable. The content of the aromatic dialdehyde in the binder composition is preferably 0.1 to 15% by mass, more preferably 0.5 to 10% by mass, and still more preferably 1 to 5% by mass, from the viewpoint of sufficiently dissolving the aromatic dialdehyde in the furan resin and from the viewpoint of suppressing the odor of the aromatic dialdehyde itself.
Examples of the tannins include condensed tannins and hydrolyzed tannins. Examples of the condensed tannins and the hydrolyzed tannins include tannins having a pyrogallol skeleton and a resorcinol skeleton. In addition, bark extract containing these tannins, and extract extracted from natural products such as leaves, fruits, seeds, and gall parasitizing on plants can be added.
[ other additives ]
The adhesive composition may further contain an additive such as a silane coupling agent. For example, when the binder composition contains a silane coupling agent, the final strength of the obtained mold can be further improved, which is preferable. As the silane coupling agent, aminosilanes such as N- β - (aminoethyl) - γ -aminopropylmethyldimethoxysilane, N- β - (aminoethyl) - γ -aminopropyltrimethoxysilane, N- β - (aminoethyl) - γ -aminopropyltriethoxysilane, and 3-aminopropyltrimethoxysilane; epoxy silanes such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane and 3-glycidoxypropyltriethoxysilane, ureidosilane, mercaptosilane, sulfide silane, methacryloxy silane and acryloxy silane. Preferred are aminosilanes, epoxysilanes, ureidosilanes. More preferably, aminosilane or epoxysilane, and still more preferably aminosilane. Among aminosilanes, N-. beta. - (aminoethyl) - γ -aminopropylmethyldimethoxysilane is preferable. The content of the silane coupling agent in the binder composition is preferably 0.01 mass% or more, and more preferably 0.05 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 binder composition is preferably 1.0% by mass or less, and more preferably 0.5% by mass or less.
The adhesive composition may contain 1 or more alcohols selected from methanol, ethanol, ethylene glycol, propylene glycol, and glycerin, from the viewpoint of suppressing economic cost. The content of the alcohol is preferably 1% by mass or more, more preferably 2% by mass or more. The content of the alcohol is preferably 10% by mass or less from the viewpoint of suppressing the decrease in the strength of the mold. The content of the alcohol is preferably 1 to 10% by mass, more preferably 2 to 10% by mass, from the viewpoint of preventing freezing in a low-temperature environment and from suppressing a decrease in the strength of the mold.
The binder composition may contain urea in order to improve the mold strength. The urea is urea that does not undergo a condensation reaction with formaldehyde, furfuryl alcohol, or the like, and may be a substance remaining as an unreacted component or a substance separately added. The content of the urea in the binder composition is preferably 0.5% by mass or more, more preferably 0.8% by mass or more, and still more preferably 1.0% by mass or more, from the viewpoint of improving the mold strength and reducing the formaldehyde concentration. The content of the urea in the binder composition is preferably 10% by mass or less, more preferably 6.0% by mass or less, and still more preferably 4.5% by mass or less, from the viewpoint of enhancing the curing rate and the storage stability of the binder composition.
The urea in the binder composition can be measured by the following LC/MS analysis procedure. The sample was prepared by 100-fold dilution with a mixed solution of acetone/water 50/50, and further 100-fold dilution with a mobile phase.
(LC/MS analysis conditions)
Column: unison UK-Amino HT
Mobile phase: 0.1% TFA acetonitrile/water 95/5
Flow rate: 0.2mL/min
Column temperature: 40 deg.C
MS：SIM m/z：61.0[M+H]+
[ phenol resin ]
The binder composition may contain a phenol resin from the viewpoint of improving the flexibility of the mold and the viewpoint of improving the final strength of the mold. The phenol resin may have a weight average molecular weight of 1000 or more and 5000 or less.
The weight average molecular weight of the phenol resin is preferably 1000 or more, more preferably 1400 or more, from the viewpoint of improving the flexibility of the mold and the ultimate strength of the mold. From the same viewpoint, it is preferably 5000 or less, and more preferably 2500 or less. Therefore, the concentration is preferably 1000 to 5000, and more preferably 1400 to 2500.
The degree of dispersion (ratio of weight average molecular weight/number average molecular weight) of the phenolic resin is preferably 1.2 or more, more preferably 1.8 or more, from the viewpoint of improving the flexibility of the mold and the ultimate strength of the mold. The weight average molecular weight of the phenol resin is preferably 5.0 or less, more preferably 3.5 or less, from the viewpoint of improving the storage stability of the binder composition, improving the flexibility of the mold, and improving the final strength of the mold. Therefore, it is preferably 1.2 to 5.0, more preferably 1.8 to 3.5.
As the phenol resin, conventionally known phenol resins can be used, and for example, 1 type of phenol resin selected from resol type phenol resins, novolak type phenol resins, and phenol resins having a structure as described in japanese patent application laid-open No. 2009-292862; a mixture of 2 or more selected from these.
In general, phenols used for obtaining the resol resin include phenol, cresol, xylenol, and the like, and phenol is preferable among these from the viewpoint of improving the flexibility of the mold and the viewpoint of improving the final strength of the mold. Examples of the aldehyde used for obtaining the resol resin include formaldehyde, glyoxal, paraformaldehyde, furfural, 5-hydroxymethylfurfural and the like, and paraformaldehyde is preferable from the viewpoint of improving the flexibility of the mold and the viewpoint of improving the final strength of the mold. Examples of the basic catalyst used for obtaining the resol resin include potassium hydroxide and sodium hydroxide.
In general, phenols and aldehydes used for obtaining a novolak-type phenol resin include those similar to resol resins.
In the production of the phenol resin composition, the raw material, water contained in the raw material, and water produced in the reaction are contained in addition to the phenol resin, and can be removed from the viewpoint of economy.
Among the above phenolic resins, a resol is preferably used from the viewpoint of solubility, the viewpoint of improving the flexibility of the mold, and the viewpoint of improving the final strength of the mold.
The content of the phenolic resin in the binder composition is 2 mass% or more and 35 mass% or less from the viewpoint of solubility, the viewpoint of improving the flexibility of the mold, and the viewpoint of improving the final strength of the mold.
The content of the phenolic resin in the binder composition is more preferably 8 mass% or more from the viewpoint of improving the flexibility of the mold and the viewpoint of improving the final strength of the mold. The content of the phenolic resin in the binder composition is more preferably 20 mass% or less from the viewpoint of solubility, the viewpoint of improving the flexibility of the mold, and the viewpoint of improving the final strength of the mold. Therefore, more preferably 8 to 20 mass%.
The total content of the furan resin and the phenol resin in the binder composition is preferably 50 mass% or more from the viewpoint of improving the final strength of the mold. The total content of the furan resin and the phenol resin in the binder composition is preferably 95 mass% or less from the viewpoint of improving the final strength of the mold. Therefore, it is preferably 50 to 95% by mass.
The binder composition is suitably used for molding a self-curing mold. Here, the self-setting mold is a mold in which when a binder composition and a curing agent composition are mixed with sand, a polymerization reaction progresses with the passage of time, and the mold is set. The temperature of the sand used in this case is in the range of-20 to 50 ℃, preferably 0 to 40 ℃. Sand at such a temperature can be appropriately solidified by selecting an appropriate amount of a solidifying agent and adding the solidifying agent to the sand.
< composition for mold >
The binder composition may be mixed with refractory particles and a curing agent composition to prepare a molding composition. The composition for a mold of the present embodiment contains the binder composition, the refractory particles, and the curing agent composition.
[ refractory particles ]
As the refractory particles, conventionally known refractory particles such as silica sand, chromite sand, zircon sand, olivine sand, alumina sand, mullite sand, synthetic mullite sand, and the like can be used, and refractory particles obtained by recovering used refractory particles, refractory particles subjected to regeneration treatment, and the like can be used.
[ curing agent composition ]
The curing agent composition may be used without particular limitation if it contains a curing agent for curing the adhesive composition. As the curing agent, an acid curing agent can be exemplified, and 1 or more of conventionally known acid curing agents such as a sulfonic acid compound such as xylene sulfonic acid (particularly m-xylene sulfonic acid), toluene sulfonic acid (particularly p-toluene sulfonic acid), methane sulfonic acid, a phosphoric acid compound such as phosphoric acid and acidic phosphate ester, and an acidic aqueous solution containing sulfuric acid can be used. From the viewpoint of workability, these compounds are preferably aqueous solutions. The curing agent may contain 1 or more kinds of solvents or carboxylic acids selected from alcohols, ether alcohols and esters.
The content of the curing agent in the curing agent composition is preferably 5 to 50% by mass, and more preferably 10 to 40% by mass, from the viewpoint of improving the final mold strength.
The composition for a mold preferably contains 0.5 to 3.0 parts by mass of the binder composition and 0.07 to 2.0 parts by mass of the curing agent composition per 100 parts by mass of the refractory particles.
From the viewpoint of improving the mold strength, the content of the curing agent composition in the mold composition is preferably 0.1 part by mass or more, more preferably 0.14 part by mass or more, further preferably 0.2 part by mass or more, preferably 0.8 part by mass or less, more preferably 0.6 part by mass or less, and further preferably 0.4 part by mass or less, relative to 1.0 part by mass of the binder composition. From the viewpoint of improving the mold strength, the content of the curing agent composition in the mold composition is preferably 0.1 to 0.8 parts by mass, more preferably 0.14 to 0.6 parts by mass, and still more preferably 0.2 to 0.4 parts by mass, based on 1.0 part by mass of the binder composition.
< method for producing casting mold >
The casting mold can be produced by curing the above-mentioned composition for a casting mold. In the method of manufacturing a mold according to the present embodiment, the mold can be manufactured by using a conventional process for manufacturing a mold as it is. A preferred method for producing a mold includes the following steps: a mixing step of mixing refractory particles, the binder composition for mold formation, and a curing agent composition for curing the binder composition for mold formation to obtain a composition for mold formation; and a curing step of filling the composition for a mold into a molding box and curing the composition for a mold.
The mixing step preferably includes: a first mixing step of mixing the refractory particles with a curing agent composition for mold formation containing the curing agent composition; and a 2 nd mixing step of mixing the binder composition for mold making with the obtained mixture after the 1 st mixing step.
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 the like may be added to the extent that the effects of the present embodiment are not impaired.
In the mixing step, as a method for mixing the respective raw materials, a known general method can be used, and examples thereof include a method for adding and kneading the respective raw materials by a batch mixer, and a method for supplying and kneading the respective raw materials to a continuous mixer.
Examples
Hereinafter, examples and the like which specifically show the present invention will be described.
< examples 1 to 9, comparative examples 1 to 4 >
[ preparation of Furan resin composition ]
100 parts by mass of furfuryl alcohol, 35 parts by mass of paraformaldehyde, and 13 parts by mass of urea were mixed in a three-necked flask and adjusted to pH9 with a 25 mass% aqueous sodium hydroxide solution. After the reaction mixture was warmed to 100 ℃, it was reacted at the same temperature for 1 hour. The pH was adjusted to 4.5 with 37 mass% hydrochloric acid, and the reaction was further carried out at 100 ℃ for 1 hour. Thereafter, the pH was adjusted to 7 with a 25 mass% aqueous solution of sodium hydroxide, 5 parts by mass of urea was added, and the mixture was reacted at 100 ℃ for 30 minutes to obtain a furan resin composition. The furan resin composition consists of: 71.7% by mass of urea-modified furan resin, 19.5% by mass of furfuryl alcohol, and 8.8% by mass of water.
[ glucose equivalent ]
2.5g of a sample was precisely weighed and dissolved in water to make 200 mL. 10mL of the liquid was accurately weighed, and 10mL of a 0.04mol/L iodine solution and 15mL of a 0.04mol/L sodium hydroxide solution were added and left in the dark for 20 minutes. Then, 5mL of 2mol/L hydrochloric acid was added and mixed, followed by titration with a 0.04mol/L sodium thiosulfate solution. When the liquid became yellowish near the end point of titration, 2 drops of the starch indicator were added dropwise to continue titration, and the end point of titration was defined as the point at which the color of the liquid disappeared. In addition, a blank test was performed, and the glucose equivalent (DE) was determined by the following formula.
DE＝(b-a)×f×3.602/(1/1000)/(200/10)/[A×(100-B)×100]×100
In the formula, a represents a titration value (mL), B represents a blank value (mL), f represents a factor value of a sodium thiosulfate solution, A represents a weighed amount (mg) of a sample, and B represents a water content value (%) of the sample. Angle (c)
[ solubility of hydrolyzed starch ]
The following operations 1 to 4 were sequentially performed on glass coils to which each of the binder compositions described in table 1 was added, to dissolve the binder compositions. The more the binder composition is dissolved by a small number operation, the higher the solubility. Here, the term "dissolution" means that the glass screw is visually observed after each operation, and the binder composition is in a uniform transparent liquid state. The results are shown in Table 1.
1: 1Hr ultrasonic treatment (37kHz) in 25 ℃ Water
2: 1Hr ultrasonic treatment (37kHz) in 50 ℃ Water
3: 2Hr ultrasonic treatment (37kHz) in 50 ℃ Water
4: 4Hr ultrasonic treatment (37kHz) in 50 ℃ Water
5: insolubility (phase separation of hydrolyzed starch in the binder composition)
[ storage stability of adhesive composition ]
Each of the binder compositions in which the hydrolyzed starch was dissolved by the above procedure was left at room temperature (25 ℃ C.) for 1 week and visually evaluated according to the following criteria.
O: the hydrolyzed starch in the binder composition is uniformly dissolved
X: separation of hydrolyzed starch phases in binder compositions
[ mold Strength ]
0.40 parts by mass of a curing agent composition (Kao Lightener C-17: manufactured by Kao-Quaker Co., Ltd.) was added to 100 parts by mass of furan reclaimed silica sand at 25 ℃ and 55% RH, and then 0.8 parts by mass of a binder composition prepared by adding and mixing the components shown in Table 1 in advance in predetermined amounts was added, and these were mixed to obtain the molding compositions according to the examples and comparative examples. The obtained molding compositions were filled in cylindrical test piece frames each having a diameter of 50mm and a height of 50mm, and demolded after 2 hours, and the compression strength (MPa) was measured 24 hours after the start of filling by the method described in JIS Z2604-1976. When the compressive strength is compared, the binder composition used for preparing the molding composition is stored at room temperature for 1 week and then shaken to be used. The results are shown in Table 1. Examples 1 to 9 were 4.7MPa or more. On the other hand, comparative examples 1 to 4 were 4.4MPa or less and had low compressive strength. This is considered to be influenced by phase separation of the hydrolyzed starch in the binder composition in the comparative example, and aggregation of the hydrolyzed starch in the molding composition.
[ Table 1]
Claims (4)
1. A binder composition for use in molding a mold,
which contains furan resin, water, and hydrolyzed starch,
the mass ratio of the furan resin to the hydrolyzed starch, i.e., the mass of the furan resin/the mass of the hydrolyzed starch, is 20-95, and the dextrose equivalent of the hydrolyzed starch is 60 or more.
2. The binder composition for molding mold according to claim 1,
the content of the hydrolyzed starch is 1 to 20 mass%.
3. A composition for casting molds, comprising:
refractory particles, the binder composition for mold making according to claim 1 or 2, and a curing agent composition containing a curing agent for curing the binder composition for mold making.
4. A method of making a casting mold, comprising:
a mixing step of mixing refractory particles, the binder composition for mold formation according to claim 1 or 2, and a curing agent composition containing a curing agent for curing the binder composition for mold formation to obtain a composition for mold formation; and a curing step of filling the composition for a mold into a molding box and curing the composition for a mold.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/JP2018/037004 WO2020070819A1 (en) | 2018-10-03 | 2018-10-03 | Binder composition for forming mold |
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| CN112203784A true CN112203784A (en) | 2021-01-08 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201880093796.6A Pending CN112203784A (en) | 2018-10-03 | 2018-10-03 | Binder composition for mold making |
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| JP (1) | JP6971412B2 (en) |
| CN (1) | CN112203784A (en) |
| WO (1) | WO2020070819A1 (en) |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4941104B1 (en) * | 1970-10-13 | 1974-11-07 | ||
| WO1980001768A1 (en) * | 1979-02-27 | 1980-09-04 | Foseco Int | Alkali metal silicate binder compositions |
| JPS61235034A (en) * | 1985-04-10 | 1986-10-20 | Kao Corp | Binder composition for casting mold |
| JPS63174752A (en) * | 1987-01-14 | 1988-07-19 | Sadaji Nagabori | Method and apparatus for continuous production of sand mold or core for casting suitable for non-coating casting |
| JPS63174754A (en) * | 1987-01-14 | 1988-07-19 | Sadaji Nagabori | Method and apparatus for batch production of sand mold or core for casting suitable for non-coating casting |
| JPH11129054A (en) * | 1997-10-30 | 1999-05-18 | Gun Ei Chem Ind Co Ltd | Component for making mold and mold manufacture |
| JPH11138234A (en) * | 1997-10-31 | 1999-05-25 | Gun Ei Chem Ind Co Ltd | Composition for forming mold and method for forming mold |
| JPH11207432A (en) * | 1998-01-26 | 1999-08-03 | Gun Ei Chem Ind Co Ltd | Molding composition for mold and molding method for mold |
| JP6026891B2 (en) * | 2012-03-09 | 2016-11-16 | 花王株式会社 | Binder composition for mold making |
-
2018
- 2018-10-03 CN CN201880093796.6A patent/CN112203784A/en active Pending
- 2018-10-03 WO PCT/JP2018/037004 patent/WO2020070819A1/en active Application Filing
- 2018-10-03 JP JP2020550999A patent/JP6971412B2/en active Active
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| JPWO2020070819A1 (en) | 2021-02-15 |
| JP6971412B2 (en) | 2021-11-24 |
| WO2020070819A1 (en) | 2020-04-09 |
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