JPH1043834A - Binder composition for carbon dioxide gas hardening - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the usable time of a mold composition for carbon dioxide gas hardening and an obtd. mold strength. SOLUTION: In a binder composition used to the mold manufacturing method for hardening an aqueous solution of a water-soluble phenolic resin with carbon dioxide gas, the water-soluble phenolic resin has the following properties and the mold composition for carbon dioxide gas hardening containing this binder composition and the molding method using this mold composition. (a) Weight- average molecular weight is 500-6000. (b) Mol ratio of aldehyde to the total mol number of phenolic and/or bisphenol is 1.0-3.0. (c) Mol ratio of alkali metal hydroxide to the total number of mol of phenolic and/or disphenol is 0.5-4.0.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a binder composition for curing carbon dioxide used in the production of a mold, a mold composition for curing carbon dioxide containing the same, and a method of molding a mold using the same. It is.

[0002]

2. Description of the Related Art As a molding method for producing a mold such as a main mold and a core using an organic binder, a self-hardening mold method, a cold box mold method, and a cloning method (shell method) are known. Among these, the organic self-hardening mold molding method is already a general-purpose molding method in place of the inorganic type mainly in the field of mechanical casting from the viewpoint of productivity, casting quality, safety and health, and the like.

On the other hand, the cloning method is a method for producing a template by heating and curing a so-called coated sand in which a phenolic resin is coated on a granular refractory, in order to produce a template at a medium / high speed. Have been.
However, in the casting industry, from the viewpoint of energy saving during mold production, improvement of mold production speed, and improvement of quality of molds and castings, as a method of producing molds instead of cloning methods, molds are made of gaseous or aerosol-like substances. Serious attempts have been made to introduce a cold box mold method of curing at room temperature.

[0004] As a binder used in the organic self-hardening mold molding method and the gas-curable mold molding method as described above, a water-soluble phenol resin is used as a binder in order to improve casting quality and work environment. Are known from JP-A-50-130627, JP-A-58-154433, JP-A-58-154434 and the like. Further, a phenolic resin obtained by polycondensation of bisphenol and formaldehyde may be used as a binder (JP-A-62-40948, JP-A-63-40636), or potassium-alkaline bisphenol-phenol copolymer Use of resole resin as binder
(Japanese Unexamined Patent Publication No. Hei 5-123818) is also known.

Recently, a process using carbon dioxide has been proposed as a gas-curing mold forming method (Japanese Patent Publication No. 1-224623). This is particularly noted from the viewpoint of health and safety because it uses carbon dioxide gas, which has less adverse effect on the human body than organic ester gas.

When a water-soluble phenol resin aqueous solution is used as a binder and the mold is actually produced by curing the solution with carbon dioxide gas, in many cases, sand and the binder are kneaded and then stored in a closed container. Take out and use according to. Here, after kneading, when curing by passing carbon dioxide gas, the maximum storage time at which a predetermined mold strength is obtained is generally referred to as the pot life, but the pot life is in the range of half a day to several days. is necessary. However, the pot life is extremely short depending on the sand. Specifically, a phenomenon in which the pot life can be obtained only for several minutes to several hours is observed, and improvement in the strength of the molded mold and the pot life has been demanded.

[0007]

In the case of using the binder composition as described above, conventionally, the amount of the resin added has to be increased as a measure to improve the mold strength and extend the pot life. Was. One of the major drawbacks of such a binder is that the so-called reclaimed sand obtained by collecting and regenerating a mold used for casting, a phenomenon in which the pot life becomes extremely short occurs. The present invention has been made in view of these problems.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, a phenol-aldehyde compound was obtained in a binder composition for a mold, which was prepared by curing an aqueous solution of a water-soluble phenolic resin with carbon dioxide gas. It has been found that by controlling the weight average molecular weight of the condensate to 500 to 6000, the pot life of the kneading sand and the mold strength can be improved. Furthermore, when a polyvalent metal salt is used in combination, a synergistic effect is exhibited,
They have found that it is possible to extend the pot life dramatically.

That is, the present invention provides a binder composition used in a mold production method in which a water-soluble phenolic resin aqueous solution is cured with carbon dioxide gas, wherein the water-soluble phenolic resin has the following properties. The present invention relates to a binder composition for curing carbon dioxide, a mold composition for curing carbon dioxide containing the same, and a mold molding method using the same. (A) The weight average molecular weight is 500 to 6000 (b) The molar ratio of aldehyde to the total number of moles of phenols and / or bisphenols is 1.0 to 3.0. (C) The alkali metal relative to the total number of moles of phenols and / or bisphenols The molar ratio of hydroxide is 0.5 to
4.0

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION

(Description of Binder) The water-soluble phenolic resin aqueous solution (binder) used in the present invention is obtained by reacting at least one selected from phenols and bisphenols with aldehydes in an alkaline aqueous solution. Obtained by
It is an alkaline resole phenol resin aqueous solution.

The phenols mentioned here include phenol, cresol, resorcin, nonylphenol, cashew nut shell liquid and the like, and the bisphenols include bisphenol A, bisphenol F, bisphenol C, bisphenol S, bisphenol Z and the like. Can be The aldehydes include formaldehyde, paraformaldehyde, acetaldehyde,
Examples thereof include dialdehydes such as furfural, glyoxal, glutardialdehyde, and phthalic dialdehyde. In addition, as a phenol raw material, phenols and bisphenols may be used alone or in combination of two or more, but a co-condensation type resin composed of phenols and bisphenols is preferable. The reason is,
This is because the mold strength is maintained higher than the resins synthesized independently. Also, a monomer condensable with an aldehyde such as urea, cyclohexanone, or melamine, or a monohydric alcohol such as methanol, ethanol, propanol, or butanol, which is an aliphatic alcohol, is mixed or co-condensed with an aqueous solution of a water-soluble phenolic resin. Alternatively, a water-soluble polymer such as polyacrylate, a cellulose derivative polymer, or PVA or a lignin derivative may be reacted or mixed. Among them, the addition of alcohols is effective in terms of the fluidity of the kneading sand and the filling property of the model, and phenol, bisphenol A,
A cresol / isopropanol / formaldehyde co-condensation resin is particularly good in mold strength and pot life.

The amount of bisphenols in the above-mentioned co-condensation resin is preferably in the range of 0.05 to 99.5 moles, more preferably 0.1 to 0.9 moles, based on the phenols. If the amount of the bisphenol is less than 0.05 times the mole of the phenol or more than 99.5 times the mole, the resulting mold strength tends to be insufficiently improved.

An aqueous solution of a water-soluble phenolic resin is prepared by subjecting one or more phenols and bisphenols (hereinafter abbreviated as phenolic compounds) and aldehydes to aldehydes in the presence of an alkali metal hydroxide in a conventional manner. The alkali metal hydroxide is in the range of 0.5 to 4.0 moles, preferably 0.8 to 3.5 moles, particularly preferably 1.0 to 4.0 moles per mole of the total phenolic compound.
It is good to use it in the range of 3.0 times mol. When the amount of the alkali metal compound is less than 0.5 times the total number of moles of the phenolic compound, the mold strength and the pot life are insufficient, while 4.
If the molar ratio exceeds 0 times, there is a risk that the working environment may be deteriorated due to an excessive amount of alkali. Suitable alkaline substances used in the production of these water-soluble phenolic resins are sodium hydroxide, potassium hydroxide, lithium hydroxide and mixtures thereof. Among them, potassium hydroxide and sodium hydroxide are preferred. preferable.

The aldehyde is in the range of 1.0 to 3.0 moles, preferably 1.1 to 3.0 moles, per mole of the phenolic compound.
It is preferably used in a range of 2.5 moles, particularly preferably in a range of 1.5 to 2.5 moles. If the aldehydes are less than 1.0 times the total number of moles of the phenolic compound, the strength of the template is low, and if it exceeds 3.0 times the moles, the residual amount of unreacted aldehydes increases.

The amount of the alcohol such as a monohydric alcohol to be used is preferably 0.0001 to 0.5 times, more preferably 0.01 to 0.2 times the mol of the phenolic compound. If the molar ratio is less than 0.0001, the effect of adding the alcohol is not obtained.
If the molar ratio exceeds twice, the mold strength tends to be insufficiently improved.

According to the present invention, the weight-average molecular weight of the water-soluble phenolic resin is 500 to 6000, preferably 800
To 4000, more preferably 1500 to 4000. If the weight average molecular weight of the resin is less than 500, the mold strength is low, 6000
When it exceeds, the pot life tends to be inferior.

(Description of Curing Accelerator) The water-soluble phenolic resin aqueous solution used in the present invention is added with an accelerator for rapidly curing with a carbon dioxide gas. As the curing accelerator, a boron compound is preferable. In addition, boric acid (reacts with an alkali in a resin to form a borate), sodium tetraborate decahydrate (borax), potassium borate
Decahydrate, sodium metaborate, sodium pentaborate, potassium pentaborate and the like can be mentioned. The addition amount of the curing accelerator is 0.1 to 100 parts by weight of the binder described above.
A range of 20 parts by weight is preferable, and a range of 3 to 10 parts by weight is particularly preferable. If the addition amount of the curing accelerator is less than 0.1 part by weight, the curing speed and strength of the mold are insufficient, and if it exceeds 20 parts by weight, the resin viscosity becomes too high, and the miscibility with sand may be insufficient. There is.

Other examples of the hardening accelerator include salts of metals that bind to ionomers with phenolic compounds, such as aluminates, stannates and titanates. Specific examples include sodium aluminate and potassium aluminate. , Lithium aluminate, sodium stannate, potassium stannate,
Examples thereof include lithium stannate, sodium titanate, and potassium titanate. These curing accelerators may be used alone or in combination.

(Explanation of polyvalent metal) Further, as a method of further extending the pot life, a polyvalent metal salt can be used in combination. Among the metal elements in the Periodic Tables 1B to 8 used in the present invention, Cu, Ag in Group 1B and Mg, C in Group 2
a, Sr, Ba, Zn, Cd, Group 3, Sc, Y, Al, Ga, In, Tl,
Ti, Zr, Hf, Sn, Pb for Group 4 V, Nb, Ta, B for Group 5
i, group 6 includes Cr, Mo, W, Po, group 7 includes Mn, Tc, Re, and group 8 includes Fe, Co, Ni.

The form of the metal element-containing compound used in the present invention includes metal powder, oxide, hydroxide, inorganic acid salt,
There are various forms such as an organic acid salt and a complex compound, and any form can be used. It suffices if the metal element is finally contained in the template composition, and is not limited to the form of the compound containing the metal element. Hereinafter, specific examples of the metal element and a compound containing the metal element will be given, but the invention is not limited thereto.

As the metal powder, Cu, Ag for Group 1B, Mg, Ca, Sr, Ba, Zn, Cd for Group 2 and the like, Al, Sc, Ga for Group 3
Group 4 includes Ti, Zr, Sn, etc., Group 5 includes Sb, Bi, etc., Group 6 includes Cr, Mo, etc., Group 7 includes Mn, Tc, etc., and Group 8 includes Fe, Co, Ni, etc. B, Si, As, Te, usually called semimetals
Are not preferred. In addition, duralumin as alloy powder,
Magnalium, ferromanganese and the like. Also,
Representative examples of compounds containing a metal element belonging to Group 1B to Group 8 of the periodic table include salts and double salts, hydroxides, oxides, hydrocarbon groups such as alkyl groups, aryl groups, and the like, which are bonded to metal atoms. Organometallic compounds, nitrides, alkoxides, hydrides, carbides, metal imides, peroxides, sulfides, phosphides, nitrates, anilides, phenolates, hexaammonides, ferrocene and similar compounds, dibenzenechromium and similar compounds Examples include compounds, inorganic heteropolymers, metal carbonyls, metal-containing enzymes, clathrate compounds, metal complexes, chelate compounds, and coordination polymers.

It is preferable to use a compound represented by the following general formula among the compounds containing the metal element belonging to Groups 1B to 8 of the periodic table, because the working time can be extended and the mold strength can be improved.

MaXb (where a, b; a positive number of 1 or more M; a metal element X of Group 1B to 8 of the periodic table X; a hydrogen atom, a carbon atom, a hydrocarbon group, a sulfur atom,
Nitrogen atom, phosphorus atom, oxygen atom, halogen atom, hydroxyl group,
It represents an alkoxide, an amino group, an imino group, a nitro group, an anionic group of an inorganic acid, an anionic group of an organic acid, or an atomic group showing a sequestering property. As for M, similarly to the above, Cu, Ag for Group 1B, Mg, Ca, Sr, Ba, Zn, Cd for Group 2 and the like, Al, Sc, Ga and the like for Group 3;
Ti, Zr, Sn, etc. for group 4; Sb, Bi, etc. for group 5; C for group 6
Group 7 includes Mn, Tc and the like in Group 7, and Group 8 includes Fe, Co, Ni and the like. However, B, Si, As, Te and the like, which are usually called semimetals, are not preferred.

Specific examples of the compound in which X is a hydrogen atom include AlH ₃ , CaH ₂ and BaH ₂ . Specific examples of the compound in which X is a carbon atom include Al ₄ C ₃ and CaC ₂ .

Specific examples of the compound in which X is a hydrocarbon group include the following organometallic compounds in which a hydrocarbon group such as an alkyl group or an aryl group is bonded to a metal atom. _{Al (CH 3) 3, Al} (C 2 H 5) 3, Al (C 6 H 5) 3, (C
_{2 H 5) 2 AlI, (} C 2 H 5) 2 AlH, (C 2 H 5) 2 AlCN, Al (iC 4 H 9) 3, (CH
₂ = CH) ₃ Al, Zn (C ₆ H ₅ ) ₂ , (CH ₂ = CH) ₂ Zn, Ca (C ₂ H ₅ ) ₂ , RM
Grignard reagents such as gX (R; alkyl or aryl group, X; halogen), ferrocene (Fe (C ₅ H ₅ ) ₂ ), Z
Ferrocene such as n (C ₅ H ₅ ) ₂ , Ni (C ₅ H ₅ ) ₂ , Mn (C ₅ H ₅ ) ₂ , V (C ₅ H ₅ ) ₂ and its analogous compounds, Cr (C ₆ H ₆ ) _{2, Mo (C 6 H 6} ) 2, V
(C ₆ H ₆ ) _{2 and} other dibenzenechromium and its analogous compounds, A
Examples include phenolates such as l-phenolate, Zn-phenolate, and Ca-phenolate.

Specific examples of the compound in which X is a sulfur atom include ZnS, Cu ₂ S, CuS and the like. Specific examples of the compound in which X is a nitrogen atom include aluminum nitride containing an Al-N bond. Specific examples of the compound in which X is a phosphorus atom include AlP and the like. Specific examples of the compound in which X is an oxygen atom include, as oxides, magnesium oxide, calcium oxide, barium oxide, zinc oxide, aluminum oxide, and the like, and further include a combination of two or more of these oxides. Complex compounds and complex compounds composed of a combination of the above oxides and oxides or salts of other elements are preferably used.

Typical examples of the compound used in the present invention include the following. Blast furnace slag which is hydraulic lime, Roman cement, natural cement, Portland cement, alumina cement, blast furnace cement, silica cement, fly ash cement, masonry cement, expansive cement, special cement, etc. and blast furnace slag, Magne refining grounds, ferrochrome grounds, bentonite, synthetic mullite, etc., whose main chemical structure is mCaO.nSi
O ₂ , mCaO.nAl ₂ O ₃ , mBaO.nAl ₂ O ₃ , CaO.mAl ₂ O _3.
nSiO ₂ , CaO · mMgO · nSiO ₂ , mCaCO ₃ · nMgCO ₃ , mCa
O ・ nFe ₂ O ₃・ lCaO ・ mAl ₂ O ₃・ nFe ₂ O ₃ 、 mAl ₂ O ₃・ nSiO
₂ (where l, m, and n are represented by a combination of 0 or 1 or more positive numbers).

In addition, there are aluminosilicates such as zeolite, calcite and calcite, and layered silicates such as mica. Examples of the peroxide include CaO ₂ , BaO ₂ , and BaO ₄ .

Examples of the compounds in which X is a halogen atom include calcium chloride, magnesium chloride, barium chloride, copper chloride, zinc chloride, calcium bromide, aluminum fluoride, vanadium chloride, molybdenum chloride, manganese chloride, and iron chloride. And nickel chloride.

Specific examples of the compound in which X is a hydroxyl group include aluminum hydroxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide and the like. Specific examples of the compound in which X is an alkoxide include Al [OCH (C
H ₃ ) ₂ ] ₃ and Zn (OCH ₃ ) ₂ .

Specific examples of the compound in which X is an amino group include Ca (NH ₂ ) _{2 and the} like. Specific examples of the compound in which X is an imino group include Al (NHPh) _{3 and the} like. Specific examples of the compound in which X is a nitro group include CuNO _{2 and the} like. Examples of the compounds in which X is an anionic group of an inorganic acid include SO ₄ , SO ₃ , S ₂ O ₃ , S ₂ O ₆ , SiF ₆ , MoO ₄ ,
MnO ₄ , NO ₃ , NO ₂ , ClO ₃ , ClO, CO ₃ , HCO ₃ , CrO ₄ , IO ₃ , P
_{O 3, PO 4, HPO 3} , HPO 4, H 2 PO 4, P 2 O 7, H 2 PO 2, SiO 3, B
O ₂ , BO ₃ , B ₄ O ₇ , Fe (CN) _{6 and the} like.

Examples of the compounds in which X is an inorganic acid include anionic groups of carboxylic acids such as formic acid, acetic acid, oxalic acid, tartaric acid, and benzoic acid, and sulfamic acid, xylenesulfonic acid, and toluenesulfonic acid. And anionic atomic groups of organic sulfonic acids such as phenolsulfonic acid, benzenesulfonic acid and alkylbenzenesulfonic acid. Further, anionic groups of organic phosphoric acids such as methylphosphoric acid and ethylphosphoric acid are exemplified.

Specific examples of compounds in which X is an atomic group exhibiting sequestering properties include the following. Representative acetic acid-based aminocarboxylic acid types include ethylenediaminetetraacetic acid (EDTA) or salts thereof, nitrilotriacetic acid (NTA) or salts thereof, trans-1,2-cyclohexanediaminetetraacetic acid (CyDTA) or salts thereof, Diethylenetriaminepentaacetic acid (DTPA) or a salt thereof,
Triethylenetetramine hexaacetic acid (TTHA) or salts thereof, glycol ether diamine tetraacetic acid (GEDTA)
Or a salt thereof, iminodiacetic acid (IDA) or a salt thereof,
Polyalkylenediaminetetraacetic acid or salts thereof, and N
-Hydroxyalkylene iminodiacetic acid or salts thereof,
A typical phenyl-based aminocarboxylic acid type is 2-
Oxyphenyliminodiacetic acid or its salts, phenyliminodiacetic acid or its salts, 2-oxybenzyliminodiacetic acid or its salts, benzyliminodiacetic acid or its salts, and N, N'-ethylenebis- [2- (O -Hydroxyphenyl)] glycine or a salt thereof is a typical aminocarboxylic acid type having a mercaptan group; β-mercaptoethyliminodiacetic acid or a salt thereof is a typical aminocarboxylic acid type having an ether bond. What is a typical example of an aminocarboxylic acid type having ethyletherdiaminetetraacetic acid or a salt thereof having a thioether bond is a typical example of an aminocarboxylic acid type having ethylthioetherdiaminetetraacetic acid or a salt thereof having a sulfonic acid group. Are β-aminoethylsulfonic acid-N, N-diacetic acid or its salts A typical example of the aminocarboxylic acid type having is nitrilotiacetic acid-methylenephosphonic acid or a salt thereof, while a typical example of the aminocarboxylic acid type having a peptide bond is N, N′-diglycylethylenediamine-N ', N'',N''', N ''''-tetraacetic acid or a salt thereof, and the typical oxycarboxylic acid type is gluconic acid or a salt thereof, citric acid or a salt thereof, and tartaric acid. Or its salts, etc., further typical of phosphoric acid type,
Examples include tripolyphosphoric acid or salts thereof, hydroxyethanediphosphonic acid (HEDP) or salts thereof, and nitrilotristyrenephosphonic acid (NTP) or salts thereof, and acetylacetone.

The coordinating polymer having a sequestering ability includes an amine group and / or a nitrogen heterocycle, and / or a Schiff base, and / or an alcohol, a carboxylic acid, and / or a ketone in the molecule. , Esters, amides, and / or aminocarboxylic acids, and / or phosphonic acids, and / or phosphines,
And / or a polymer having a thiol.

Examples of the inclusion compound include cyclic polyethers (crown ethers), cyclic polyamines (azacrown compounds), cyclic polythiaethers (thiacrown compounds), composite donor crown compounds, multicyclic crown compounds (cryptands), Complexes with molecular crown compounds, cyclic phenols (kaxarenes), cyclodextrin derivatives and the like can be mentioned. For example dibenzo-18-crown-6 complexes with Ca ^2+, Ca ²⁺ of Kuriputado [2 · 2 · 2]
And the like.

Other examples include metal carbonyls such as Ni (CO) ₄ and Mn ₂ (CO) ₁₀ ; metal-containing enzymes such as carboxypeptidase A and thermolysin; and zircoaluminum compounds. Among the metal-containing compounds of Groups 1B to 8 described in these specific examples, preferred metal elements are the metal elements of Groups 2 to 8, more preferably the metal elements of Groups 2, 3, and 4, Among them, Zn, Ca, Mg, Al and Zr are particularly preferable.

Further, the compound containing a metal element belonging to Groups 1B to 8 of the periodic table includes at least one selected from an aluminate compound, a stannate compound, a titanate compound and a zirconate compound. As the aluminate compound, magnesium aluminate, sodium aluminate,
Potassium aluminate, lithium aluminate, etc., as stannate compounds, sodium stannate, potassium stannate,
Lithium stannate and the like, as titanate compounds, lithium titanate, sodium titanate, potassium titanate,
Examples of barium titanate and the like and zirconate compounds include lithium zirconate, sodium zirconate and potassium zirconate. The pot life can be improved by using these compounds in combination with a boric acid compound. The determination of the metal element in the sand and the binder is generally performed as follows. [Quantitative Determination of the Metal Element in Sand] Sand is ground to 150 mesh or less, and 0.2 to 0.3 g is weighed in a 100 ml platinum dish. 5 ml of concentrated hydrochloric acid, 3 ml of concentrated hydrofluoric acid and 10 ml of concentrated perchloric acid
After volatilization, 10 ml of HCl (1 + 1) +10 ml of H ₂ O are added, and the mixture is heated to dissolve residual salts. This is filtered (No5C filter paper) and washed with dilute hydrochloric acid + warm water. 30 ml of residue left on the filter paper
After incineration at 900 to 1000 ° C in a platinum crucible, the mixture was allowed to cool, 2 g of potassium pyrosulfate was added, and the mixture was acid-melted at 800 ° C. The extracted melt is combined with the above filtrate to make a 100 ml solution in a volumetric flask, and the metal element is quantified by ICP (inductively coupled plasma emission analysis). In addition, HCl (1 + 1)
Is a mixture of hydrochloric acid (36% product) and water in the same volume ratio.

[Quantitative Determination of the Metal Element in the Binder] The binder is thoroughly mixed and stirred, and 0.5 to 0.8 g is weighed in a 100 ml platinum dish. To this, 10 ml of concentrated nitric acid is added, and after acid decomposition, it is subjected to weak thermal decomposition. Add 10 ml of concentrated perchloric acid, treat with white smoke, and concentrate 3
ml. After allowing to cool, 10 ml of HCl (1 + 1) +10 ml of H ₂ O are added and dissolved by heating. This is filtered (No5C filter paper) and washed with dilute hydrochloric acid + warm water. The residue remaining on the filter paper is ashed in a 30 ml platinum crucible at 900 to 1000 ° C., then allowed to cool, 2 g of potassium pyrosulfate is added and melted at 800 ° C. The extracted melt is combined with the above filtrate to make a 100 ml solution in a volumetric flask, and the metal element is quantified by ICP (inductively coupled plasma emission analysis).

In order to produce the binder composition for hardening carbon dioxide of the present invention, the above-mentioned metal element-containing compound is added to the water-soluble phenolic resin in a solid content of 0.0005 in terms of the metal element.
To 5% by weight (50 to 50,000 ppm), preferably 0.001 to 3% by weight. When the amount of the compound is less than 0.0005% by weight, the effect of the present invention is not sufficient, and when the amount exceeds 5% by weight, the effect is in a saturation region.

As a mode in which the aqueous solution of a water-soluble phenolic resin and the above-mentioned metal element-containing compound are used in combination, a polycondensation reaction with an aldehyde is carried out after dissolving or mixing the metal element-containing compound in phenol in advance. The metal element-containing compound may be dissolved or mixed at the stage where the polycondensation of phenols and aldehydes has progressed, or may be contained in a water-soluble phenolic resin or an aqueous solution. The effect is comparable to that of adding them separately to sand.

(Explanation of Glycols) Further, glycols may be added to the binder used in the present invention. Usually, 1 to 20 parts by weight of the glycol is added to 100 parts by weight of the water-soluble phenolic resin. If the amount is less than 1 part by weight, the effect of improving the strength of the mold is not obtained, but if it exceeds 20 parts by weight, curing is adversely affected. Examples of the glycols include diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, and diethylene glycol monoethyl. Ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monopropyl ether, triethylene glycol monobutyl ether, propylene glycol monomethyl ether, dipropylene glycol Monomethyl ether, and the like.

(Description of Silane Coupling Agent) In the binder composition of the present invention, conventionally known silane coupling agents can be used as other additives. Specific examples thereof include γ-aminopropyltriethoxysilane, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and the like. In the present invention, it is preferable to use this silane coupling agent together with a binder composition. As the amount of addition, the binder composition 10
0.01 to 3.0 parts by weight, preferably 0.1 to 2.0 parts by weight per 0 parts by weight
Parts by weight. If the amount is less than 0.01 part by weight, there is no effect on the strength of the mold, and if it exceeds 3.0 parts by weight, no improvement in the effect is observed. In addition, these silane coupling agents can be separately added and added when the binder composition is mixed with the refractory granular material.

(Description of Refractory Granular Material) Examples of the refractory granular material include quartz sand, chromite sand,
Examples include zircon sand, olivine sand, alumina sand, and artificially synthesized mullite sand, but are not particularly limited. In the present invention, these refractory granular materials may be either new sand or reclaimed sand. In particular, when reclaimed sand is used, the effect of improving the mold strength is remarkable. When reclaimed sand is used, a reclaimed sand obtained by a normal abrasion or roasting method is used, but the method for producing the reclaimed sand is not particularly limited.

(Description of Mold Composition and Mold Molding Method) When a mold is formed with an aqueous solution of a water-soluble phenolic resin for curing a carbon dioxide gas, the strength and strength of the mold can be improved by using the aqueous solution of a water-soluble phenolic resin for curing a carbon dioxide gas described above. It is possible to provide a mold molding method that is excellent in use time. The hardening gas can be molded by passing a carbon dioxide gas, which is an acidic gas, into a mold, and can be molded using a mold obtained by the method of the present invention to produce a non-ferrous alloy such as an aluminum casting or a cast steel or a cast iron casting. In particular, there is no particular limitation on the use of the casting material and castings.

As a molding method, the binder composition for hardening carbon dioxide of the present invention is used in an amount of 0.1 part by weight per 100 parts by weight of the refractory granular material.
It is 1 to 10 parts by weight, preferably 0.5 to 5 parts by weight. Under such conditions, the mold composition for hardening carbon dioxide obtained as kneading sand is filled in a gas mold model having vent holes (vent holes, etc.), and carbon dioxide gas is ventilated to mold the mold. As the amount of carbon dioxide gas used, the mold can be formed by ventilating 0.01 to 30 parts by weight, preferably 0.1 to 15 parts by weight, per 100 parts by weight of the refractory granular material. If the binder composition for curing carbon dioxide is 100 parts by weight of the refractory granular material and the amount is less than 0.1 part by weight, the mold strength is insufficient, and if it exceeds 10 parts by weight, the gas permeability of the carbon dioxide gas only deteriorates. Or uneconomic. Also, the amount of carbon dioxide used is 100 parts by weight of the refractory granular material, and if it is less than 0.01 part by weight, it tends to be uncured,
If it exceeds 30 parts by weight, the productivity of mold making will decrease.

Examples of the refractory granular material include quartz sand, chromite sand, zircon sand, olivine sand, and the like.
Examples include alumina sand, mullite sand, and synthetic mullite sand. In the present invention, these refractory granular materials may be fresh sand, reclaimed sand, or mixed sand of one or more of these. Further, the particle size and particle size distribution of these refractory granular materials are not particularly limited.

As other mold making methods, the present invention is applied to a VRH molding method in which kneading sand is filled, and then the pressure is reduced and the pressure is replaced with carbon dioxide to normal pressure to cure the mold, and a vacuum molding method which is a suction molding method. It is possible to use it, and it is not particularly limited, and other molding methods may be used.

[0048]

EXAMPLES The present invention will be described below with reference to examples.
The present invention is not limited only to these examples.

<Description of Synthesis and Preparation of Binder Composition for Curing Carbon Dioxide Gas> In a 50% aqueous solution of potassium hydroxide, phenols, bisphenols, and alcohols in amounts specified by the molar ratio shown in Table 1 were added. In addition, the mixture was stirred and dissolved. While maintaining this solution at 80 ° C., an amount of the aldehyde compound also determined by the molar ratio shown in Table 1 was slowly added over 1 hour. And phenol in the reaction solution
The weight average molecular weight of the aldehyde condensate is about 300 and 5 respectively.
When the sample reached 00, 800, 1500, 2500, 4000, 6000 and 8000, sampling was performed and the reaction was continued at 80 ° C. The determination at the time when each weight average molecular weight was reached was performed by measuring the viscosity of the reaction solution. After the sampling was completed, potassium hydroxide was added while cooling to room temperature.
The blending amount was calculated such that the molar ratio of potassium hydroxide was 1.0 with respect to the total of the phenolic compounds. At this time, the solid content was adjusted to be 55% to obtain a resin stock solution. For 100 parts by weight of this resin stock solution, 10 parts by weight of a curing accelerator and 15 parts by weight of triethylene glycol, and 0.5 part by weight
A part by weight of γ-aminopropyltriethoxysilane was blended to prepare a binder composition for curing carbon dioxide. The methods for measuring the solid content and the weight average molecular weight are described below.

(Measurement method of solid content) The solid content of the water-soluble phenolic resin or the phenol-aldehyde condensate in the present invention was determined by uniformly spreading a sample (about 2 g) weighed on a 10 cm diameter petri dish, It measured by heating in a furnace (105 degreeC) for 3 hours.

(Method of measuring weight average molecular weight) In a 500 ml beaker, about 2 g of a phenol-aldehyde condensate was weighed,
Further dilute with the same amount of water. A 0.1% by weight aqueous solution of sulfuric acid is added thereto until pH 3 is adjusted, and the formed precipitate is further washed with water while being separated by filtration, and the obtained residue is dried at 5 ° C. This was dissolved in tetrahydrofuran (THF) to a concentration of 0.5 to 1% to prepare a sample for GPC. GPC measurement conditions are shown below. Column: Toyo Soda Co., Ltd. TSK-GEL G3000HXL, TSK-GE
L G2500HXL Column connection method: Guard column → TSK-GUARD COLUMN HXL-L
+ TSK-GEL G3000HXL + TSK-GEL G2500HXL Standard substance: polystyrene (manufactured by Tosoh Corporation) Eluent: THF (flow rate 1 ml / min, pressure 40 to 70 kgf / cm ²⁾ Column temperature: 40 ° C. Detector: UV For calculating molecular weight Division method: time division (10 seconds) In addition, a water-soluble phenol resin aqueous solution is mixed with a curing accelerator used in the present invention, a metal element selected from Groups 1B to 8 of the periodic table, glycols, and a silane coupling agent. Even when the so-called carbon dioxide curing hardener composition was measured by the above-described method for measuring the weight average molecular weight, almost the same value of the weight average molecular weight was obtained.

[0052]

[Table 1]

Examples 1 to 6 and Comparative Examples 1 to 4 The periodic table 1B of the amount obtained in Synthesis Example 1 of the water-soluble phenolic resin aqueous solution for curing carbon dioxide gas was added in the amount specified in Table 2.
A metal compound consisting of a metal element selected from Group 8 to Group 8 was added and blended to obtain the desired binder composition for curing carbon dioxide. The recycled sand 3 coated with a binder composition for hardening carbon dioxide having an ignition loss (LOI%) of 0.8%
90 g of the binder composition for hardening carbon dioxide was taken per kg, and the kneaded sand obtained by kneading with a batch mixer for 1 minute was put in a plastic bag, air was shut off, and after 4 hours, 50 mmφ50
The test piece model for hardening carbon dioxide gas composed of eight mmh size frames was filled and carbon dioxide gas was ventilated for 1 minute to obtain a test piece mold. Immediately, the coercive pressure was measured with a coercive force tester. The higher the coercive pressure, the longer the mold strength and the pot life. At this time, the carbon dioxide gas flow rate was 20 liters / minute, and the carbon dioxide gas pressure was 2 kg / cm ² . Carbon dioxide was used in an amount of 100 parts by weight based on 100 parts by weight of the binder composition for hardening carbon dioxide.

The method for measuring the% loss on ignition is shown below.

(Measurement Method of Burning Loss%) Sample 10 from which free moisture was removed by JIS Z-2605 (moisture test method for foundry sand)
g is weighed accurately and placed in an electric furnace maintained at about 1000 ° C in advance. After igniting for 1 hour, remove the crucible and allow it to cool to room temperature in a desiccator using silica gel as a drying agent.
Weigh accurately. The burning loss% is calculated by the following equation.

[0056]

(Equation 1)

(Where W ₁ is the sample weight (g) before ignition and W ₂ is the sample weight (g) after ignition).

[0058]

[Table 2]

Examples 7 to 12 and Comparative Examples 5 to 8 The periodic table 1B having the amount determined in Table 3 and the amount obtained in Synthesis Example 2 of the aqueous phenolic resin aqueous solution for curing carbon dioxide gas.
A metal compound consisting of a metal element selected from Group 8 to Group 8 was added and blended to obtain the desired binder composition for curing carbon dioxide. Then, the recycled sand 3 coated with the binder composition for hardening carbon dioxide having an ignition loss (LOI%) of 0.8% 3
90 g of the binder composition for hardening carbon dioxide was taken per kg, and the kneaded sand obtained by kneading with a batch mixer for 1 minute was put in a plastic bag, air was shut off, and after 4 hours, 50 mmφ50
The test piece model for hardening carbon dioxide gas composed of eight mmh size frames was filled and carbon dioxide gas was ventilated for 1 minute to obtain a test piece mold. Immediately, the coercive pressure was measured with a coercive force tester. The higher the coercive pressure, the longer the mold strength and the pot life. At this time, the gas flow rate of carbon dioxide gas was 30 liter / min, and the carbon dioxide gas pressure was 2 kg / cm ² . Carbon dioxide was used in an amount of 150 parts by weight based on 100 parts by weight of the binder composition for hardening carbon dioxide.

[0060]

[Table 3]

Examples 13 to 18 and Comparative Examples 9 to 12 The periodic table 1B of the amount obtained in Synthesis Example 3 of the water-soluble phenolic resin aqueous solution for curing carbon dioxide gas in the amount specified in Table 4
A metal compound consisting of a metal element selected from Group 8 to Group 8 was added and blended to obtain the desired binder composition for curing carbon dioxide. Then, the recycled sand 3 coated with the binder composition for hardening carbon dioxide having an ignition loss (LOI%) of 0.8% 3
90 g of the binder composition for hardening carbon dioxide was taken per kg, and the kneaded sand obtained by kneading with a batch mixer for 1 minute was put in a plastic bag, air was shut off, and after 4 hours, 50 mmφ50
The test piece model for hardening carbon dioxide gas composed of eight mmh size frames was filled and carbon dioxide gas was ventilated for 1 minute to obtain a test piece mold. Immediately, the coercive pressure was measured with a coercive force tester. The higher the coercive pressure, the longer the mold strength and the pot life. At this time, the carbon dioxide gas flow rate was 20 liters / minute, and the carbon dioxide gas pressure was 2 kg / cm ² . Carbon dioxide was used in an amount of 100 parts by weight based on 100 parts by weight of the binder composition for hardening carbon dioxide.

[0062]

[Table 4]

Examples 19 to 24 and Comparative Examples 13 to 16 The periodic table 1B having the amount determined in Table 5 and the amount obtained in Synthesis Example 4 of a water-soluble phenolic resin aqueous solution for curing carbon dioxide gas.
A metal compound consisting of a metal element selected from Group 8 to Group 8 was added and blended to obtain the desired binder composition for curing carbon dioxide. Then, the recycled sand 3 coated with the binder composition for hardening carbon dioxide having an ignition loss (LOI%) of 0.8% 3
90 g of the binder composition for hardening carbon dioxide was taken per kg, and the kneaded sand obtained by kneading with a batch mixer for 1 minute was put in a plastic bag, air was shut off, and after 4 hours, 50 mmφ50
The test piece model for hardening carbon dioxide gas composed of eight mmh size frames was filled and carbon dioxide gas was ventilated for 1 minute to obtain a test piece mold. Immediately, the coercive pressure was measured with a coercive force tester. The higher the coercive pressure, the longer the mold strength and the pot life. At this time, the carbon dioxide gas flow rate was 20 liters / minute, and the carbon dioxide gas pressure was 2 kg / cm ² . Carbon dioxide was used in an amount of 100 parts by weight based on 100 parts by weight of the binder composition for hardening carbon dioxide.

[0064]

[Table 5]

Examples 25 to 30 and Comparative Examples 17 to 20 The periodic table 1B of the amount obtained in Synthesis Example 5 of the water-soluble phenolic resin aqueous solution for curing carbon dioxide gas was added in the amount specified in Table 6.
A metal compound consisting of a metal element selected from Group 8 to Group 8 was added and blended to obtain the desired binder composition for curing carbon dioxide. Then, the recycled sand 3 coated with the binder composition for hardening carbon dioxide having an ignition loss (LOI%) of 0.8% 3
90 g of the binder composition for hardening carbon dioxide was taken per kg, and the kneaded sand obtained by kneading with a batch mixer for 1 minute was put in a plastic bag, air was shut off, and after 4 hours, 50 mmφ50
The test piece model for hardening carbon dioxide gas composed of eight mmh size frames was filled and carbon dioxide gas was ventilated for 1 minute to obtain a test piece mold. Immediately, the coercive pressure was measured with a coercive force tester. The higher the coercive pressure, the longer the mold strength and the pot life. At this time, the carbon dioxide gas flow rate was 20 liters / minute, and the carbon dioxide gas pressure was 2 kg / cm ² . Carbon dioxide was used in an amount of 100 parts by weight based on 100 parts by weight of the binder composition for hardening carbon dioxide.

[0066]

[Table 6]

Examples 31 to 36 and Comparative Examples 21 to 22 Periodic Table 1B with the amount determined in Table 7 obtained in Synthesis Example 1 of a water-soluble phenolic resin aqueous solution for curing carbon dioxide.
A metal compound consisting of a metal element selected from Group 8 to Group 8 was added and blended to obtain the desired binder composition for curing carbon dioxide. Then, the recycled sand 3 coated with the binder composition for hardening carbon dioxide having an ignition loss (LOI%) of 0.8% 3
90 g of the binder composition for hardening carbon dioxide was taken per kg, and the kneaded sand obtained by kneading with a batch mixer for 1 minute was put in a plastic bag, air was shut off, and after 4 hours, 50 mmφ50
The test piece model for hardening carbon dioxide gas composed of eight mmh size frames was filled and carbon dioxide gas was ventilated for 1 minute to obtain a test piece mold. Immediately, the coercive pressure was measured with a coercive force tester. The higher the coercive pressure, the longer the mold strength and the pot life. At this time, the gas flow rate of carbon dioxide gas was 10 liter / min, and the carbon dioxide gas pressure was 2 kg / cm ² . Carbon dioxide was used in an amount of 50 parts by weight based on 100 parts by weight of the binder composition for hardening carbon dioxide.

[0068]

[Table 7]

Examples 37 to 42 and Comparative Examples 23 to 24 The periodic table 1B having the amount determined in Table 8 and the amount obtained in Synthesis Example 2 of a water-soluble phenolic resin aqueous solution for curing carbon dioxide gas was used.
A metal compound consisting of a metal element selected from Group 8 to Group 8 was added and blended to obtain the desired binder composition for curing carbon dioxide. Then, the recycled sand 3 coated with the binder composition for hardening carbon dioxide having an ignition loss (LOI%) of 0.8% 3
90 g of the binder composition for hardening carbon dioxide was taken per kg, and the kneaded sand obtained by kneading with a batch mixer for 1 minute was put in a plastic bag, air was shut off, and after 4 hours, 50 mmφ50
The test piece model for hardening carbon dioxide gas composed of eight mmh size frames was filled and carbon dioxide gas was ventilated for 1 minute to obtain a test piece mold. Immediately, the coercive pressure was measured with a coercive force tester. The higher the coercive pressure, the longer the mold strength and the pot life. At this time, the carbon dioxide gas flow rate was 20 liters / minute, and the carbon dioxide gas pressure was 2 kg / cm ² . Carbon dioxide was used in an amount of 100 parts by weight based on 100 parts by weight of the binder composition for hardening carbon dioxide.

[0070]

[Table 8]

Examples 43-48 and Comparative Examples 25-26 Periodic Table 1B in the amount obtained in Synthesis Example 4 of an aqueous solution of a water-soluble phenolic resin for curing carbon dioxide gas with the amount specified in Table 9
A metal compound consisting of a metal element selected from Group 8 to Group 8 was added and blended to obtain the desired binder composition for curing carbon dioxide. Then, the recycled sand 3 coated with the binder composition for hardening carbon dioxide having an ignition loss (LOI%) of 0.8% 3
90 g of the binder composition for hardening carbon dioxide was taken per kg, and the kneaded sand obtained by kneading with a batch mixer for 1 minute was put in a plastic bag, air was shut off, and after 4 hours, 50 mmφ50
The test piece model for hardening carbon dioxide gas composed of eight mmh size frames was filled and carbon dioxide gas was ventilated for 1 minute to obtain a test piece mold. Immediately, the coercive pressure was measured with a coercive force tester. The higher the coercive pressure, the longer the mold strength and the pot life. At this time, the carbon dioxide gas flow rate was 20 liters / minute, and the carbon dioxide gas pressure was 2 kg / cm ² . Carbon dioxide was used in an amount of 100 parts by weight based on 100 parts by weight of the binder composition for hardening carbon dioxide.

[0072]

[Table 9]

Examples 49-54 and Comparative Examples 27-28 The periodic table 1B having the amount specified in Table 10 and the amount obtained in Synthesis Example 5 of a water-soluble phenolic resin aqueous solution for curing carbon dioxide was used.
A metal compound consisting of a metal element selected from Group 8 to Group 8 was added and blended to obtain the desired binder composition for curing carbon dioxide. Then, the recycled sand 3 coated with the binder composition for hardening carbon dioxide having an ignition loss (LOI%) of 0.8% 3
90 g of the binder composition for hardening carbon dioxide was taken per kg, and the kneaded sand obtained by kneading with a batch mixer for 1 minute was put in a plastic bag, air was shut off, and after 4 hours, 50 mmφ50
The test piece model for hardening carbon dioxide gas composed of eight mmh size frames was filled and carbon dioxide gas was ventilated for 1 minute to obtain a test piece mold. Immediately, the coercive pressure was measured with a coercive force tester. The higher the coercive pressure, the longer the mold strength and the pot life. At this time, the gas flow rate of carbon dioxide gas was 10 liter / min, and the carbon dioxide gas pressure was 2 kg / cm ² . Carbon dioxide was used in an amount of 50 parts by weight based on 100 parts by weight of the binder composition for hardening carbon dioxide.

[0074]

[Table 10]

Claims (9)

[Claims] 1. A binder composition used in a mold production method for curing an aqueous solution of a water-soluble phenolic resin with carbon dioxide gas, wherein the water-soluble phenolic resin has the following properties: Binder composition. (A) The weight average molecular weight is 500 to 6000 (b) The molar ratio of aldehyde to the total number of moles of phenols and / or bisphenols is 1.0 to 3.0. (C) The alkali metal relative to the total number of moles of phenols and / or bisphenols The molar ratio of hydroxide is 0.5 to
4.0 2. The water-soluble phenolic resin is a resin obtained by cocondensing one or more compounds selected from phenols, one or more compounds selected from bisphenols, and an aldehyde compound. 2. The binder composition for hardening carbon dioxide according to 1. 3. The binder composition according to claim 2, wherein a mixture of phenol and cresol is used as the phenol. 4. The binder composition for curing carbon dioxide according to claim 2, wherein bisphenol A or bisphenol F is used as the bisphenol. 5. The binder composition for hardening carbon dioxide gas according to claim 1, wherein the water-soluble phenolic resin is obtained by further co-condensing an alcohol. 6. The carbon dioxide curing resin binder composition according to claim 1, further comprising a boron compound as an essential component. 7. One selected from the periodic table 1B to group 8
The carbon dioxide curing viscosity according to any one of claims 1 to 6, wherein the metal element contains at least 0.0005 to 5% by weight of the metal element based on the solid content of the resin. Binder composition. 8. A binder composition for hardening carbon dioxide according to any one of claims 1 to 7, which is contained in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the refractory granular material. Mold composition for curing carbon dioxide. 9. A kneading agent obtained by using 0.1 to 10 parts by weight of the binder composition for hardening carbon dioxide according to claim 1 with respect to 100 parts by weight of the refractory granular material. A mold molding method characterized in that 0.01 to 30 parts by weight of carbon dioxide gas is passed through sand to cure the sand.