JP3301236B2 - Binder composition for mold and method for producing mold - Google Patents

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 use in producing a mold, and relates to the flowability of kneaded sand obtained by kneading the binder composition with a refractory granular material. It is intended to improve the filling property. The present invention also relates to a method for producing a mold using the binder composition.

[0002]

2. Description of the Related Art Conventionally, a mold is prepared by filling a model with kneaded sand obtained by kneading a refractory granular material and a binder composition, and then curing the binder in the binder composition. Being manufactured. As the binder, various curable resins such as a furan resin, a water-soluble phenol resin, and a urethane resin are used. Among these, a water-soluble phenol resin is known to be capable of preventing deterioration of the working environment at the time of producing a self-hardening or gas-curable mold since it is cured with an organic ester or carbon dioxide gas (Japanese Patent Application Laid-Open No. 50-130627). JP-B, JP-B-61-43132, JP-B-61-37022).
The water-soluble phenolic resin referred to herein is an alkaline phenol-formaldehyde resin, which is obtained by condensation polymerization of phenol and formaldehyde in the presence of an alkali or after addition of an alkali after condensation polymerization.

[0003] However, when the binder composition containing the alkaline phenol-formaldehyde resin and the refractory granular material are kneaded to produce a mold, the binder composition containing a furan resin is used. Compared to the case, the fluidity of the kneaded sand was poor, and there was a regret that the kneaded sand could not be packed tightly in the model. If the fluidity of the kneading sand is poor, there is a disadvantage that it is difficult to uniformly knead the binder and the refractory granular material. In addition, if the filling property of the kneading sand with respect to the model is poor, irregularities may occur on the surface of the obtained mold, or the surface strength of the mold may decrease. Therefore, when a mold obtained by using an alkaline phenol-formaldehyde resin as a binder is used, casting defects such as sand scum, baking, insertion, squeezing, etc. occur in the obtained casting, causing deterioration in casting quality. There was a disadvantage.

For this reason, a binder composition containing an alkaline phenol-formaldehyde resin may contain a fluorine-based surfactant as a glidant (Japanese Patent Laid-Open No. 2-29).
No. 9741) or to contain an aliphatic alcohol (JP-A-3-34067).
However, fluorine-based surfactants and aliphatic alcohols have poor compatibility with alkaline phenol-formaldehyde resins and the like, failing to sufficiently improve the fluidity of kneaded sand.

In recent years, a binder composition containing an alkaline bisphenol-phenol copolymer type resole resin (alkaline bisphenol-phenol-formaldehyde resin) has been proposed in which a high-strength template can be obtained with a small amount of use. (Japanese Unexamined Patent Publication No. Hei 5-12818). When the binder composition containing this alkaline bisphenol-phenol-formaldehyde resin is used, the fluidity of the kneaded sand is slightly improved as compared with the case where the binder composition containing the alkaline phenol-formaldehyde resin is used. However, the degree of the improvement was within the range of the error. Basically, the fluidity of the kneaded sand was poor, and the kneaded sand could not be tightly filled in the model.

[0006]

Accordingly, the present inventors have sought to solve the above-mentioned drawbacks of alkaline phenol-formaldehyde resins and alkaline bisphenol-phenol-formaldehyde resins when kneaded with refractory granular materials. Various studies were conducted. Then, the present inventors changed the structure of phenol-formaldehyde resin or alkaline bisphenol-phenol-formaldehyde resin itself, that is, instead of using only phenol (and bisphenol) and formaldehyde, polycondensation was performed. The present inventors have found that the co-condensation polymerization with the addition of alcohols can improve the fluidity of the kneaded sand and the filling property of the kneaded sand when the kneaded sand is kneaded with the refractory granular material, thereby achieving the present invention. Also, by adding ether alcohols to this copolycondensation product, without decreasing the fluidity of the kneading sand and the filling property of the model, it was found that the mold strength was improved, and the present invention was reached. .

[0007]

That is, the present invention provides a binder composition for a mold mainly containing a phenol-aldehyde-modified resin, wherein the phenol-aldehyde-modified resin comprises phenols, bisphenols, The present invention relates to a binder composition for a mold, which is obtained by co-condensation polymerization of an alcohol and an aldehyde compound. The present invention also relates to a method for producing a mold using the binder composition for a mold.

[0008] In the binder composition for a mold according to the present invention,
A phenol-aldehyde modified resin is mainly contained. The phenol-aldehyde-modified resin is obtained by copolycondensation of a phenol, a bisphenol, an alcohol, and an aldehyde compound. As the phenols, a compound represented by the following general formula (1), a compound represented by the following general formula (2), or a compound represented by the following general formula (3) is used alone or in combination. .

[0009]

Embedded image (In the formula, R ₁ and R ₂ represent a hydrogen atom or a hydrocarbon group having 2 or less carbon atoms.)

[0010]

Embedded image (In the formula, R ₃ represents a hydrogen atom or a hydrocarbon group having 2 or less carbon atoms.)

[0011]

Embedded image (In the formula, R ₄ represents an aliphatic hydrocarbon group or an aromatic hydrocarbon group having 3 to 9 carbon atoms.)

Among the phenols, specific examples of the compound represented by the general formula (1) include phenol, cresol, 3,5-xylenol and the like. The compound represented by the general formula (2) is a polyhydric phenol, and specific examples include resorcinol and catechol. The compound represented by the general formula (3) mainly has 3 carbon atoms at the para position.
The above alkyl group or phenyl group is bonded,
Specific examples include nonylphenol, P-tert-butylphenol, isopropenylphenol, phenylphenol and the like. Also, a mixture of various phenols such as cashew nut shell liquid can be used. In particular,
As the phenols, it is preferable to use a mixture of phenol and cresol.

As the bisphenols, compounds represented by the following general formula (4) are used alone or in combination.

[0014]

Embedded image

Specific examples of the bisphenols represented by the general formula (4) include bisphenol A, bisphenol F, bisphenol C, bisphenol E, bisphenol Z, bisphenol S, bisphenol AF, bisphenol AP, di-sec-butyl-bisphenol. A, di
-Isopropyl-bisphenol A, 1,1-ethylidene-bisphenol, methyl-ethyl-methylene-bisphenol, methyl-isobutyl-methylene-bisphenol, methyl-hexyl-methylene-bisphenol, methyl-phenyl-methylene-bisphenol, 4,4 ' -Thiodiphenol, etc., which are used alone or in combination.

Alcohols mainly have 2 carbon atoms.
Preferred are monohydric alcohols of from 10 to 10, such as ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol, isobutyl alcohol, and the like.
Examples thereof include sec-butyl alcohol, tert-butyl alcohol, n-amyl alcohol, isoamyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, caprylic alcohol, nonyl alcohol, and decyl alcohol. In particular, it is most preferable to use propyl alcohol, isopropyl alcohol, butyl alcohol, isobutyl alcohol, sec-butyl alcohol or tert-butyl alcohol as the monohydric alcohol.

As the aldehyde compound, formaldehyde, paraformaldehyde, furfural, glyoxal and the like are used alone or in combination.

When co-polycondensation of phenol, bisphenol, alcohol and aldehyde compound,
The molar ratio of each compound is preferably as follows. That is, the ratio of the number of moles of the aldehyde compound to the number of moles of the phenol, the number of moles of the bisphenol, and the number of moles of the alcohol is 1.0 to 5.0 [(the number of moles of the phenol + the number of moles of the bisphenol + the number of moles of the alcohol). Mole number): mole number of aldehyde compound = 1: 1.0 to 5.0]. In particular, the molar ratio of the aldehyde compound is more preferably 1.5 to 3.0. When the ratio of the number of moles of the aldehyde compound is less than 1.0, there is a tendency that the strength of the mold is not sufficiently improved even when molding using the obtained phenol-aldehyde-modified resin. Conversely, if the ratio of the number of moles of the aldehyde compound exceeds 5.0, the obtained phenol-aldehyde-modified resin has a strong odor of aldehyde, which may deteriorate the working environment.

The ratio of the number of moles of the bisphenol to the number of moles of the phenol is preferably 0.01 to 100 (the number of moles of the phenol: the number of moles of the bisphenol = 1: 0.01 to 100). In particular, the molar ratio of bisphenols is more preferably 0.05 to 10. If the molar ratio of the phenolic compound is less than 0.01 or exceeds 100, the strength of the mold tends not to be sufficiently improved even when molding using the obtained phenol-aldehyde-modified resin.

The ratio of the number of moles of alcohol to the total number of moles of phenols and bisphenols is 0.0001 to 0.5 [(moles of phenols + moles of bisphenols): It is preferable that the number of moles of alcohols = 1: 0.0001 to 0.5]. In particular, the molar ratio of alcohols is more preferably 0.01 to 0.2. When the molar ratio of the alcohols is less than 0.0001, the flowability of the kneading sand and the filling property to the model tend to be reduced even when the obtained phenol-aldehyde-modified resin is used. Conversely, when the number of moles of alcohols exceeds 0.5, the strength of the mold tends not to be sufficiently improved even when the resulting phenol-aldehyde-modified resin is used for molding.

Copolycondensation of phenols, bisphenols, alcohols, and aldehyde compounds is generally carried out in an aqueous solution to obtain a phenol-aldehyde-modified resin. For example, it is preferable to obtain by co-condensation polymerization while gradually adding a predetermined amount of an aldehyde compound to an aqueous solution in which a predetermined amount of a phenol, a bisphenol and an alcohol are dissolved. At this time, KOH, NaOH, and LiOH are preferably used as a reaction catalyst, but KOH is most preferable. Since the phenol-aldehyde-modified resin in the present invention is adjusted to an alkaline aqueous solution, a predetermined amount of potassium hydroxide may be used at the time of copolycondensation, or a minimum amount of potassium hydroxide is used as a reaction catalyst. After completion of the copolycondensation, a predetermined amount of potassium hydroxide may be added. After the completion of the copolycondensation, sodium hydroxide (NaOH) or lithium hydroxide (LiOH) may be used in combination with potassium hydroxide so as to have a predetermined alkalinity. Further, after co-condensation polymerization using an acid catalyst, co-condensation polymerization may be subsequently advanced using an alkali catalyst such as potassium hydroxide. In the aqueous alkali solution of the phenol-aldehyde-modified resin, the ratio of the mole number of the total alkali to the mole number of the hydroxyl group of the phenol (at the time of preparation) and the mole number of the hydroxyl group of the bisphenol (at the time of preparation) is 0.2%. Preferably it is ~ 1.2. The concentration of the phenol-aldehyde-modified resin in the aqueous alkali solution is preferably 30 to 75% by weight.

The binder composition for a mold according to the present invention contains a phenol-aldehyde-modified resin as a main component, and preferably further contains an ether alcohol. This is because if such an ether alcohol is incorporated into the binder composition for a mold, the strength of the resulting mold can be improved. The ether alcohols used here include 2-methoxyethanol, 2-ethoxyethanol, 2-isopropoxyethanol, 2-butoxyethanol, 2- (isopentyloxy) ethanol, 2- (hexyloxy) ethanol, Alkylene oxide (or poly) of furfuryl alcohol such as phenoxyethanol, 2-benzyloxyethanol, furfuryl alcohol, ethylene oxide (or polyethylene oxide) adduct of furfuryl alcohol, and propylene oxide (or polypropylene oxide) adduct of furfuryl alcohol Alkylene oxide) adducts, block or random copolymer adducts of ethylene oxide and propylene oxide of furfuryl alcohol, tetrahydrofurfuryl alcohol, diethylene glycol Le, triethylene glycol, tetraethylene glycol, polyethylene glycol (molecular weight 200 to 20,000), dipropylene glycol,
Tripropylene glycol, polypropylene glycol (molecular weight 400 to 4000), diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, 1-methoxy-2-
Examples thereof include propanol, 1-ethoxy-2-propanol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether, and polypropylene glycol. Further, a compound composed of a cyclic ether alcohol and an open-chain ether alcohol can also be used. The mixing ratio of the ether alcohol is preferably 0.5 to 30% by weight in the aqueous solution of the binder composition for a mold. If it is outside this range, the strength of the resulting mold tends not to be significantly improved.

In order to further improve the strength of the obtained mold, it is preferable that the aqueous solution of the binder composition for a mold further contains a silane coupling agent. Various conventionally known silane coupling agents can be used. In particular, γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-
(2-aminoethyl) aminopropyltrimethoxysilane,
N-glycidyl-N, N-bis [3- (trimethoxysilyl) propyl] amine and the like can be used.

In the binder composition for a mold according to the present invention, various surfactants such as a nonionic surfactant, a cationic surfactant, an anionic surfactant and an amphoteric surfactant, or urea and a urea compound may be used. By containing an organic nitrogen compound such as an amide compound or an amide compound, it is possible to further improve the fluidity of the kneaded sand kneaded with the refractory granular material and the filling property to the model. Further, when reclaimed sand is used as the refractory granular material, the strength of the resulting mold can be improved by including various polyvalent metal salts such as calcium chloride and aluminum oxide in the binder composition for the mold. Can be improved.

In order to produce a mold using the binder composition for a mold according to the present invention, a self-hardening mold molding method or a gas-curable mold molding method is generally employed. As a specific example of the self-hardening molding method, 0.1 to 5 parts by weight of an organic ester is added and kneaded with 100 parts by weight of the refractory granular material. Subsequently, the binder composition for a mold according to the present invention is added so as to be 0.4 to 15 parts by weight in the form of an aqueous alkali solution, and kneaded again. The kneaded sand thus obtained is filled in a model and left to cure, whereby a self-hardening mold can be obtained.
Further, as a specific example of the gas-curable mold molding method, the binder composition for a mold according to the present invention is 0.4 to 15 parts by weight in the form of an aqueous alkaline solution, based on 100 parts by weight of the refractory granular material. And knead it. The obtained kneading sand is filled into a gas curing model by blowing with pressurized air. Then, gaseous or aerosol organic ester 0.05 to 10
By blowing and hardening a part by weight, a gas-curable mold can be obtained. As the organic ester to be used, alkyl formate having 1 to 3 carbon atoms in the alkyl group, preferably methyl formate can be used.

In place of the gaseous organic ester,
When using a carbon dioxide gas to cure the binder composition for a mold, an appropriate amount of a compound having an oxyanion is added to the binder composition, and the compound having the oxyanion and the carbon dioxide gas are mixed. The phenol-aldehyde-modified resin can be cured by the action (Japanese Patent Laid-Open No. 1-2242).
No. 63). As the compound having an oxyanion,
Boric acid, sodium tetraborate (borax), potassium borate decahydrate, borate salts such as sodium metaborate, potassium pentaborate and sodium pentaborate, and perborate salts such as potassium perborate and sodium perborate can be used. . Other usable materials include aluminates and stannates. The aluminate is a salt formed from aluminum oxide and a basic metal oxide, and specifically, sodium aluminate, potassium aluminate, lithium aluminate and the like are used. The stannate is a salt formed from tin oxide and a basic metal oxide, and specifically, sodium stannate, potassium stannate, lithium stannate and the like are used.

As the refractory granular material used in manufacturing the mold, various known materials can be used. For example, quartz sand, chromite sand, zircon sand, olivine sand mainly composed of quartz can be used. , Alumina sand, mullite sand, synthetic mullite sand and the like can be used. Also,
It goes without saying that a material mainly composed of such recycled sand and recovered sand can also be used as the refractory granular material.

[0028]

【Example】

[Preparation of aqueous solution of binder composition for mold 1] In a 50% aqueous solution of potassium hydroxide, phenols, bisphenols, and alcohols in amounts determined by the molar ratios shown in the columns of Examples 1 to 7 of Table 1 Was added and stirred to dissolve. 80 this solution
While maintaining the temperature at ° C, an amount of the aldehyde compound determined by the molar ratio shown in the columns of Examples 1 to 7 of Table 1 was gradually added. And, until the weight average molecular weight of the phenol-aldehyde-modified resin in the reaction solution reaches 2500, 80
The reaction was continued at ° C. The determination when the weight-average molecular weight reached 2500 was made by measuring the viscosity of the reaction solution. The method of measuring the weight average molecular weight of the phenol-aldehyde-modified resin is as follows. That is, an appropriate amount of water is added to the sample, and H ₂ SO ₄ is added to neutralize the sample. The precipitate formed is separated by filtration, washed with water and dried. This is dissolved in tetrahydrofuran (THF) to obtain a sample for molecular weight measurement. The measurement uses polystyrene as a standard substance and
Performed by the PC method. The weight average molecular weight of the phenol-aldehyde-modified resin measured in this way and the correlation between the viscosity are determined in advance, and the viscosity of the reaction solution is measured.
It is adjusted so as to have a desired weight average molecular weight.

After completion of the reaction, the mixture is cooled to room temperature, and then the ratio of the number of moles of potassium hydroxide to the total number of moles of hydroxyl groups of phenols (when charged) and moles of hydroxyl groups of bisphenols (when charged). Is 0.85,
A 50% aqueous potassium hydroxide solution was added. As described above, an alkaline aqueous solution of the phenol-aldehyde-modified resin was obtained. Then, γ-glycidoxypropyltrimethoxysilane was added to a 0.5 part by weight aqueous solution with respect to 100 parts by weight of the aqueous solution. As described above, seven types of aqueous solution of the binder composition for a mold were prepared. The content of the binder composition (phenol-aldehyde-modified resin and silane coupling agent) in the aqueous solution of the binder composition was 50% by weight.

[0030]

[Table 1]

The item A in Table 1 is the ratio of the number of moles of the aldehyde compound to the total number of moles of phenols, bisphenols, and alcohols. That is, [mol number of aldehyde / (mol number of phenols + mol number of bisphenols + mol number of alcohols)]. Item B is the ratio of the number of moles of bisphenols to the number of moles of phenols. That is, [mol number of bisphenol / mol number of phenol]. Item C is the ratio of the number of moles of alcohols to the total number of moles of phenols and bisphenols. That is, [mol number of alcohols / (mol number of phenols + mol number of bisphenols)]. Hereinafter, A, B and C in the table are the same.

[Preparation of aqueous solution of binder composition for template] An aqueous solution of binder composition for template was prepared except that the reaction was continued until the weight average molecular weight of the phenol-aldehyde-modified resin in the reaction solution reached 1800. In the same manner as in Example 1, seven kinds of aqueous binder composition solutions for molds 2 were prepared.

[Preparation of aqueous solution of binder composition for mold 3] In the preparation of aqueous solution of binder composition for mold 2, 90 parts by weight of an aqueous solution of a phenol-aldehyde-modified resin obtained after the completion of the reaction was added. 5 parts by weight of sodium borate decahydrate, 95%
By mixing with 5 parts by weight of potassium hydroxide, seven kinds of aqueous binder composition solutions for molds 3 were prepared.

[Preparation of aqueous solution of binder composition for mold 4] 50
Phenol was added to a 5% aqueous potassium hydroxide solution and dissolved by stirring. While maintaining the solution at 80 ° C., formaldehyde was gradually added so as to have a ratio of 1.5 moles to phenol moles. Then, the reaction was continued at 80 ° C. until the weight average molecular weight of the phenol-formaldehyde resin in the reaction solution reached 2500. The determination when the weight-average molecular weight reached 2500 was made by measuring the viscosity of the reaction solution. After the reaction was completed, the mixture was cooled to room temperature, and the ratio of the number of moles of potassium hydroxide to the number of moles of hydroxyl groups of the phenol (at the time of preparation) was 0.85.
, A 50% aqueous potassium hydroxide solution was added. As described above, an alkaline aqueous solution of a phenol-formaldehyde resin was obtained. Then, γ-glycidoxypropyltrimethoxysilane was added to a 0.5 part by weight aqueous solution with respect to 100 parts by weight of the aqueous solution. As described above, one kind of aqueous solution of the binder composition for a mold was prepared. The solid content of the binder composition (phenol-formaldehyde resin and silane coupling agent) in the aqueous solution of the binder composition was 50% by weight.

[Preparation of aqueous solution of binder composition for mold 5] The aqueous solution of binder composition for mold 4 was prepared except that the reaction was continued until the weight average molecular weight of the phenol-formaldehyde resin in the reaction solution reached 1800. In the same way as
Various kinds of aqueous binder composition solutions for molds 5 were prepared.

[Preparation of aqueous solution of binder composition for mold 6] In the preparation of aqueous solution of binder composition for mold 5, an aqueous solution of phenol-formaldehyde resin 90 obtained after completion of the reaction was prepared.
Parts by weight, 5 parts by weight of sodium tetraborate decahydrate, 95
And 5 parts by weight of potassium hydroxide, thereby preparing one kind of aqueous solution 6 of the binder composition for a mold.

[Preparation of aqueous solution of binder composition for mold 7] Bisphenol A was used in place of phenol, and the amount of formaldehyde was based on the number of moles of bisphenol A.
One type of aqueous solution of a binder composition for a mold 7 was prepared in the same manner as the aqueous solution of a binder composition for a mold 4 except that the amount was 3 times.

[Preparation of aqueous solution of binder composition for mold 8] Instead of phenol, a mixture of phenol and bisphenol A (the molar ratio of bisphenol A / phenol is 0.1%)
4/1) and the amount of formaldehyde is twice the total number of moles of phenol and bisphenol A, except that it is twice the total number of moles. By using the above method, one kind of aqueous solution of the binder composition for a mold 8 was prepared.

[Preparation of aqueous solution of binder composition for template 9] Bisphenol A was used in place of phenol, and the amount of formaldehyde was based on the number of moles of bisphenol A.
One type of aqueous solution of a binder composition for a mold 9 was prepared in the same manner as the aqueous solution of a binder composition for a mold 5 except that the amount was 3 times.

[Preparation of aqueous solution of binder composition for template 10] In place of phenol, a mixture of phenol and bisphenol A (the molar ratio of bisphenol A / phenol is 0.1%)
4/1) and the amount of formaldehyde is twice as large as the total number of moles of phenol and bisphenol A, and is the same as that of the aqueous solution of the binder composition for a mold 5. Aqueous solution of one kind of binder composition for a mold
Adjusted 10.

[Preparation of aqueous solution of binder composition for mold 11] Bisphenol A was used in place of phenol, and the amount of formaldehyde was based on the number of moles of bisphenol A.
One type of aqueous solution of the binder composition for mold 11 was prepared in the same manner as in the aqueous solution of the binder composition for mold 6 except that the amount was 3 times.

[Preparation of aqueous solution of binder composition for mold 12] Instead of phenol, a mixture of phenol and bisphenol A (the molar ratio of bisphenol A / phenol was 0.1%).
4/1) and the amount of formaldehyde is twice as large as the total number of moles of phenol and bisphenol A, and is the same as that of the aqueous solution of the binder composition for mold 6. Aqueous solution of one kind of binder composition for a mold
12 has been adjusted.

Examples 1 to 7 0.3 parts by weight of triacetin as a hardening agent was added to 100 parts by weight of silica sand as a refractory granular material and kneaded. Subsequently, seven kinds of aqueous binder composition solutions 1 for mold prepared in advance were added and kneaded so as to be 1.5 parts by weight to obtain seven kinds of kneaded sand. Then, the fluidity / filling property of the kneaded sand was measured by the following method. That is, the pedestal is attached to the bottom of a test tube with an inner diameter of 50 mm and an internal effective length of 100 mm, and passed through a 3 mm sieve.
A test tube is roughly filled with kneading sand. Next, the excess kneading sand at the top was scraped off and applied to a “Compactability Tester manufactured by George Fisher Co.” and pressurized with a squeeze pressure of 10 kg / cm ² . Thereafter, a decrease in the height of the kneading sand was measured, and the reduced height X mm [= C. B. (Compactability)] was used as an index for the fluidity and filling property of the kneading sand. The results are shown in Table 1. The smaller the value of X, the better the fluidity and filling properties of the kneaded sand.

Comparative Examples 1 to 3 The same procedures as in Example 1 were carried out except that the aqueous binder composition for mold compositions 4, 7 and 8 were used instead of the aqueous binder composition solution for mold 1 as shown in Table 1. Similarly, kneaded sand was obtained. Then, using this kneaded sand, C.I. B. Was measured, and the results are shown in Table 1.

Comparative Example 4 Kneading sand was prepared in the same manner as in Example 1 except that an aqueous solution obtained by adding butyl alcohol to the aqueous binder composition solution for a mold 4 was used instead of the aqueous binder composition solution for a mold 1. Obtained. In addition, the addition amount of butyl alcohol was 0.1 mol with respect to 1 mol of phenol used when obtaining the binder composition aqueous solution 4 for a mold. And, using this kneading sand,
C. B. Was measured, and the results are shown in Table 1.

Examples 8 to 14 To 100 parts by weight of silica sand, which is a refractory granular material, 7 kinds of aqueous binder composition solutions 2 for molds prepared in advance were added and kneaded so as to be 2.0 parts by weight each. And seven types of kneaded sand were obtained.
C. of each kneading sand. B. Was measured in the same manner as in Example 1.
The results are shown in Table 2. In Table 2, types of phenols and the like are described in the same manner as in Table 1.

Comparative Examples 5 to 7 The same procedures as in Example 8 were carried out except that the aqueous solution of the binder composition for molds 5, 9, and 10 was used instead of the aqueous solution 2 of the binder composition for molds as shown in Table 2. Similarly, kneaded sand was obtained. Then, using this kneaded sand, C.I. B. Was measured, and the results are shown in Table 2.

Comparative Example 8 Kneading sand was prepared in the same manner as in Example 8 except that an aqueous solution obtained by adding butyl alcohol to an aqueous solution of a binder composition for a mold 5 was used instead of the aqueous solution of the binder composition for a mold 2. Obtained. The amount of butyl alcohol added was 0.1 mol with respect to 1 mol of phenol used when obtaining the aqueous solution of the binder composition for template 5. And, using this kneading sand,
C. B. Was measured, and the results are shown in Table 2.

[0049]

[Table 2]

Examples 15 to 21 To 100 parts by weight of silica sand, which is a refractory granular material, seven kinds of aqueous solution 3 of a binder composition for a mold prepared in advance were added so as to be 3.0 parts by weight and kneaded. And seven types of kneaded sand were obtained.
C. of each kneading sand. B. Was measured in the same manner as in Example 1.
Table 3 shows the results. In Table 3, types of phenols and the like are described in the same manner as in Table 1.

Comparative Examples 9 to 11 The procedure of Example 15 was repeated except that the aqueous solution of the binder composition for molds 6, 11, and 12 was used instead of the aqueous solution of the binder composition for mold 3 as shown in Table 3. Similarly, kneaded sand was obtained. Then, using this kneaded sand, C.I. B. Was measured, and the results are shown in Table 3.

Comparative Example 12 Kneading sand was prepared in the same manner as in Example 15 except that an aqueous solution obtained by adding butyl alcohol to the aqueous solution of the binder composition for mold 6 was used instead of the aqueous solution of the binder composition for mold 3. Obtained. The amount of butyl alcohol added was 0.1 mol based on 1 mol of phenol used when obtaining the aqueous solution 6 of the binder composition for a mold. And, using this kneading sand,
C. B. Was measured, and the results are shown in Table 3.

[0053]

[Table 3]

As is clear from the results in Tables 1 to 3, the phenol-aldehyde-modified resin obtained by copolycondensation of four compounds of phenols, bisphenols, alcohols and aldehyde compounds was used as a binder composition. If kneading sand is obtained by using as a main component, a phenol (bisphenol) -aldehyde resin obtained by copolycondensation of phenols and / or bisphenols with an aldehyde compound is compared with a case where a binder composition is used as a main component. And C. of the kneading sand
B. It can be seen that the value of Therefore, Example 1
It can be seen that the kneaded sand obtained by the methods according to Comparative Examples 1 to 21 has better fluidity and is more excellent in the filling property to the model than the kneaded sand obtained by the methods according to Comparative Examples 1 to 12.

Examples 22 to 28 90 parts by weight of each of the seven aqueous binder composition aqueous solutions 3 for molds used in Examples 15 to 21 were used, and 10 parts by weight of the ether alcohols shown in Table 4 were added thereto. The added aqueous solution of the binder composition for a mold was prepared. Then, 3.5 parts by weight of each of the aqueous solution of the binder composition for a mold was added and kneaded to 100 parts by weight of domestic silica sand No. 6 to obtain kneaded sand. This mixed sand is 50mmφ × 50mmh
Into a gas mold for CO ₂ gas pressure of 2 kg / cm ² , CO ₂
A test piece was obtained by bubbling CO ₂ at a gas flow rate of 20 L / min for 1 minute. After leaving it for 24 hours, the resistance of the test piece (mold strength: kgf / cm
² ) was measured. Table 4 shows the results.

Examples 29 to 35 and Comparative Example 13 For comparison with Examples 22 to 28, the seven types of aqueous binder composition solutions 3 for molds used in Examples 15 to 21 were used to prepare ether alcohols. A test piece was prepared in the same manner as in Example 22 except that no compounds were added, and the coercive pressure was measured. The results are also shown in Table 4. Further, a test piece was prepared using the aqueous solution of the binder composition for mold 6 used in Comparative Example 9 in the same manner as in Example 22 except that ether alcohols were not added, and the resistance to pressure was measured. The results are also shown in Table 4.

[0057]

[Table 4]

As is clear from comparison between Examples 22 to 28 and Examples 29 to 35 in Table 4, when an aqueous solution of the binder composition for a mold containing ether alcohols was used, the strength of the mold was increased. Is remarkably improved. Example 22
The fluidity of the kneaded sand in Nos. To 28 was almost the same as in Examples 15 to 21 and Examples 29 to 35.

[0059]

As described above, the binder composition for a mold according to the present invention containing a specific phenol-aldehyde-modified resin as a main component is kneaded with a refractory granular material by kneading. , The kneaded sand is excellent in fluidity and filling in a model. The kneading sand with good fluidity is
The kneading agent can be sufficiently kneaded, and the mixing of the binder composition and the refractory granular material can be uniform. Also, if this kneading sand is used, the model can be filled tightly,
Irregularities on the surface of the resulting mold or reduction in the surface strength of the mold can be prevented. Therefore, when a casting is obtained using a mold obtained by using the binder composition for a mold according to the present invention, it is possible to prevent the occurrence of casting defects such as sand scum, baking, insertion, and squeezing. This has the effect of preventing a decrease in casting quality. In addition, when ether alcohols are further added to the binder composition for a mold according to the present invention, the strength of the obtained mold is remarkably improved.

Continuation of the front page (56) References JP-A-4-118150 (JP, A) JP-A-63-142016 (JP, A) JP-A-61-9735 (JP, A) JP-A-60-64745 (JP, A) JP-A-59-78745 (JP, A) JP-A-57-68240 (JP, A) JP-A-53-58430 (JP, A) JP-A-55-149744 (JP, A) 4-279241 (JP, A) JP-A-4-168118 (JP, A) JP-A-1-224263 (JP, A) JP-A-6-210392 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B22C 1/22 C08G 4/00-16/06

Claims (11)

(57) [Claims] 1. A binder composition for a mold containing a phenol-aldehyde-modified resin as a main component, wherein the phenol-aldehyde-modified resin comprises a phenol, a bisphenol, an alcohol, and an aldehyde compound. A binder composition for a mold, which is obtained by polymerization. 2. The mold viscosity according to claim 1, wherein the ratio of the number of moles of the aldehyde compound to the total number of moles of the phenols, the bisphenols, and the alcohols is 1.0 to 5.0. Binder composition. 3. The binder composition according to claim 1, wherein the ratio of the number of moles of bisphenol to the number of moles of phenol is 0.01 to 100. 4. The mold according to claim 1, wherein the ratio of the number of moles of alcohol to the total number of moles of phenols and bisphenols is 0.0001 to 0.5. Binder composition for use. 5. The binder composition for a mold according to claim 1, wherein a mixture of phenol and cresol is used as the phenol. 6. The binder composition for a mold according to any one of claims 1 to 5, wherein a monohydric alcohol having 2 to 10 carbon atoms is used as the alcohol. 7. The method according to claim 1, wherein the alcohol is selected from the group consisting of propyl alcohol, isopropyl alcohol, butyl alcohol, isobutyl alcohol, sec-butyl alcohol and tert-butyl alcohol. Item 4. The binder composition for a mold according to Item 1. 8. The binder composition for a mold according to claim 1, which is mainly composed of a phenol-aldehyde-modified resin and further contains ether alcohols. 9. The binder composition for a mold according to claim 1, which is mainly composed of a phenol-aldehyde-modified resin and further contains an oxyanion compound. 10. An oxyanion compound selected from the group consisting of boric acid, sodium tetraborate decahydrate, potassium borate decahydrate, sodium metaborate, sodium pentaborate, perborate, aluminate, and stannate. 10. The binder composition for a mold according to claim 9, wherein one or more selected ones are used. A method for producing a mold, comprising using the binder composition for a mold according to any one of claims 1 to 10, and using an organic ester and / or carbon dioxide gas as a curing agent. .