JPH07102421B2 - Composition for casting sand caking - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is a composition for casting sand caking used in the production of molds or cores, and in particular, has high strength in baking and molding the molds or cores.
In addition, the present invention relates to a molding sand caking composition for use in the production of a mold or core having good thermal disintegration after pouring.

(Prior Art) Regarding conventional casting molds and cores, regardless of the type of alloy, for example, as described in "Plastic Technology Complete Document 15" issued by the Industrial Research Institute, phenol resin as a mold binder is used. The shell mold method using is widely used as the manufacturing method. Especially in the core, productivity,
Most of them are manufactured by the shell mold method because of their excellent dimensional accuracy.

However, when a phenol resin is used as a binder in a mold of a low-melting light metal casting such as an aluminum alloy, especially in the core, a part of the phenol resin undergoes a thermal change due to the heat of the molten metal, resulting in an extremely strong graphitized structure. Because of the change, the residual strength of the core is remarkably high, and after casting, heating is performed at a high temperature of about 500 ° C. for about 5 to 10 hours for a long time called “sand baking” to form a graphitized structure. The binder residue that has become a problem is burned and discharged, and it has a drawback that a large amount of energy is required to be consumed. Therefore, a highly disintegrating mold material for the shell mold method, which is easily decomposed by heat of molten metal, has been desired.

On the other hand, based on the results of research that phenolic resins have excellent heat resistance due to the benzene ring, a thermosetting resin that does not contain a benzene ring has been sought, but it is still satisfactory. However, when a resin that causes thermal decomposition easily due to the heat of dissolution of the aluminum alloy is used as the binder, the strength of the mold or core during firing molding is weak, and the aluminum alloy There was a problem that the molding core was broken by heat during casting and the heat resistance was poor.

(Problems to be Solved by the Invention) From such a background, JP-A-62-203636 and 63-
In Japanese Patent No. 97327, a novel epoxy resin having an oxycyclohexane skeleton or a composition for casting sand binding using an epoxy resin and a phenol formaldehyde resin was proposed.

However, since the epoxy resin described in the above-mentioned Japanese Patent Laid-Open Publication has a relatively low softening temperature, the resin and the resin-coated sand using the resin are likely to be blocked particularly when the epoxy resin is left under high temperature in summer. Therefore, in the case of a resin, an antiblocking agent such as calcium stearate is added and used as a foundry sand binder, and in the case of resin-coated sand, the amount of a lubricant is increased to prevent blocking.

However, there is a problem in that the strength of the core decreases when the amount of the antiblocking agent or the lubricant added increases.

Further, there is a problem that a composition for casting sand caking having a high fusion point of 90 ° C. or higher and a tensile strength of 24 kg / cm ² or higher cannot be obtained.

(Means for Solving the Problem) The present invention significantly improves the problems of the prior art, has high strength, has good thermal disintegration after pouring, and is also excellent in blocking resistance. The present invention provides a composition for casting sand caking, which is suitable for casting an aluminum alloy or the like.

That is, the first invention of the present invention is a polyether obtained by addition-polymerizing (A) 4-vinylcyclohexene-1-oxide and a compound having two or more epoxy groups to a compound having one or more active hydrogens. Epoxy compound (a) obtained by epoxidizing a compound
And (B) a phenol formaldehyde resin (b), which is a composition for caking foundry sand.

When using this foundry sand caking composition as a binder,
The (B) phenol formaldehyde resin (B) acts as a curing agent for the (A) epoxy compound (A).

In the epoxy compound (A) used in the present invention and the polyether compound as the raw material thereof, examples of the organic compound having active hydrogen include alcohols, phenols, carboxylic acids, amines, thiols and the like. .

The alcohol may be a monohydric alcohol or a polyhydric alcohol.

For example, methanol, ethanol, propanol, butanol, pentanol, hexanol, octanol and other aliphatic alcohols, aromatic alcohols such as benzyl alcohol, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol,
1,3-butanediol, 1,4-butanediol, pentanediol, 1,6-hexanediol, neopentyl glycol, oxypivalic acid neopentyl glycol ester, cyclohexanedimethanol, glycerin, diglycerin, polyglycerin, trimethylol propane,
Examples include polyhydric alcohols such as trimethylolethane, pentaerythritol, and dipentaerythritol.

Examples of phenols include phenol, cresol, catechol, pyrogallol, hydroquinone, hydroquinone monomethyl ether, bisphenol A, bisphenol F, 4,4'-dihydroxybenzophenone, bisphenol S, phenol resin and cresol novolac resin.

Carboxylic acids include formic acid, acetic acid, propionic acid, butyric acid, fatty acids of animal and vegetable oils, fumaric acid, maleic acid, adipic acid, dodecane diacid, trimellitic acid, pyromellitic acid, polyacrylic acid, phthalic acid, isophthalic acid, terephthalic acid. Acid etc.

Further, compounds having both a hydroxyl group and a carboxylic acid, such as lactic acid, citric acid and oxycaproic acid, can also be mentioned.

As the amines, monomethylamine, dimethylamine,
Monoethylamine, diethylamine, propylamine,
Monobutylamine, dibutylamine, pentylamine,
Hexylamine, cyclohexylamine, octylamine, dodecylamine, 4,4'-diaminodiphenylmethane, isophoronediamine, toluenediamine, hexamethylenediamine, xylenediamine, diethylenetriamine, triethylenetetramine, ethanolamine and the like.

Examples of thiols include methyl mercaptan, ethyl mercaptan, propyl mercaptan, mercapto such as phenyl mercaptan, mercaptopropionic acid or polyhydric alcohol ester of mercaptopropionic acid, such as ethylene glycol dimercaptopropionic acid ester, trimethylolpropane trimercaptopropionic acid, Examples thereof include pentaerythritol pentamercaptopropionic acid.

Furthermore, as the compound having active hydrogen, polyvinyl alcohol, polyvinyl acetate partial hydrolyzate, starch, cellulose, cellulose acetate, cellulose acetate butyrate, hydroxyethyl cellulose,
There are acrylic polyol resin, styrene allyl alcohol copolymer resin, styrene-maleic acid copolymer resin, alkyd resin, polyester polyol resin, polyester carboxylic acid resin, polycaprolactone polyol resin, polypropylene polyol, polytetramethylene glycol, and the like.

The compound having active hydrogen may have an unsaturated double bond in its skeleton, and specific examples thereof include allyl alcohol, acrylic acid, methacrylic acid, 3-cyclohexenemethanol, tetrahydrophthalic acid and the like. is there.

Any compound having these active hydrogens can be used, and two or more kinds of them may be mixed.

The 4-vinylcyclohexene-1-oxide in the epoxy resin used in the present invention has the following formula And is industrially produced by partially epoxidizing 4-vinylcyclohexene obtained by dimerization of butadiene with peracetic acid, hydrogen peroxide or the like.

The compound having two or more epoxy groups in the epoxy resin used in the present invention may be any compound as long as it is a compound having two or more epoxy groups in one molecule,
These can be used alone or in combination of two or more.

For example Alicyclic epoxy resin such as (However, R ¹ is a hydrogen atom, an aliphatic or aromatic substituent)
Polyalcohol and polyglycol glycidyl ether, epoxidized soybean oil, epoxidized linseed oil and other polyolefin type epoxy resins, diglycidyl hydantoin, triglycidyl isocyanurate and other heterocyclic epoxy resins, tetraglycidyl diaminodiphenylmethane, triglycidyl Glycidylamine resins such as p-aminophenol, glycidyl ester resins such as phthalic acid diglycidyl ester and tetrahydrophthalic acid diglycidyl ester, and other bisphenol A
Type epoxy resin, bisphenol F type epoxy resin, novolac type epoxy resin and the like.

The polyether compound which is a precursor of the novel epoxy compound in the composition for casting sand according to the present invention is a compound having at least one active hydrogen described above, 4-vinylcyclohexene-1-oxide, and at least two epoxy groups. It can be obtained by reacting the compound with the compound in the presence of a catalyst.

In this case, in the obtained polyether compound, 4-
A compound having two or more vinylcyclohexene-1-oxides and epoxy groups includes a linear structure in which the epoxy groups that they have are randomly bonded to each other by an ether bond generated by ring-opening, and a part thereof has a crosslinked structure. Change in structure.

The point of the present invention is to use an epoxy resin having a partially crosslinked structure introduced into the molecule.

In addition, depending on the reaction conditions described below, the epoxy group may be 2
In some cases, some epoxy groups in the compound having more than one group may remain.

In the compound having at least one active hydrogen used as an initiator in the epoxy resin used in the present invention, the residue of the alkyl portion, the ether group and the terminal hydrogen atom remain in the epoxy compound.

For example, when trimethylolpropane CH ₃ CH ₂ C (CH ₂ OH) ₃ is used as a compound having one or more active hydrogens, the resulting polyether compound has a residue and a terminal hydrogen atom having the following structure. Will remain.

CH ₃ CH ₂ C (CH ₂ O) ₃ (Y) _n H ₃ (I) [In the formula (I), n is a natural number of 3 to 100 and has at least one active hydrogen used in the reaction. Depending on the usage ratio of the compound and the compound having two or more 4-vinylcyclohexene-1-oxide and epoxy groups, Y is a compound having two or more 4-vinylcyclohexene-1-oxide and two epoxy groups, and the epoxy group moiety is open. Random bond structure that is linked by ether bond part formed by ring or partially cross-linked structure part, and depending on reaction conditions, 2 or more molecules of CH ₃ CH ₂ C (CH ₂ O) ₃ (Y) _n H ₃ A structure in which Y is crosslinked at the Y portion can also be taken. ] During the reaction, a compound having one epoxy group other than 4-vinylcyclohexene-1-oxide can be copolymerized.

However, 4-vinylcyclohexene-1-oxide and 4-vinylcyclohexene-1-oxide
The proportion of the compound having one epoxy group other than vinylcyclohexene-1-oxide must be in the range of 1 to 100% for the former and 99 to 0% for the latter.

If the former is less than 1%, the content of vinyl groups will be small, and the characteristics of the cyclohexane skeleton will not be exhibited. The reaction is a combination of 4-vinylcyclohexene-1-oxide and a compound having one epoxy group other than 4-vinylcyclohexene-1-oxide, and 0.01 mol of a compound having one or more active hydrogens per mol. ~ 1 mol, 0.001 to 0.5 mol of the compound having two or more epoxy groups, preferably
The reaction is carried out at a ratio of 0.01 to 0.2 mol.

If the amount of the compound having one or more active hydrogen is less than 0.01 mol, the compound does not act as an initiator.

In addition, compounds with more than two epoxy groups are 0.001
If it is less than the molar amount, the epoxy compound cannot be modified,
If it exceeds 0.5 mol, the molecular weight becomes too high to be practically usable.

When addition-polymerizing a mixture of 4-vinylcyclohexene-1-oxide and a compound having two or more epoxy groups with a compound having one or more active hydrogens, two 4-vinylcyclohexene-1-oxides and two epoxy groups are added. The compounds having the above can be reacted simultaneously.

Further, either 4-vinylcyclohexene-1-oxide or a compound having two or more epoxy groups can be reacted first, and the reaction adduct can be reacted with the other.

Further, either 4-vinylcyclohexene-1-oxide and a compound having two or more epoxy groups are simultaneously reacted, and either one is subjected to addition polymerization. Alternatively, one of which is reacted first and 4-vinylcyclohexene-1-oxide and a compound having two or more epoxy groups can be simultaneously reacted. Examples of the catalyst used in the reaction include amines such as methylamine, ethylamine, propylamine and piperazine, organic bases such as pyridine and imidazole, quaternary ammonium salts such as tetrabutylammonium bromide, formic acid, acetic acid and propionic acid. Organic acids, inorganic acids such as sulfuric acid and hydrochloric acid, alcoholates of alkali metals such as sodium methylate, KO
Examples thereof include alkalis such as H and NaOH, Lewis acids such as BF ₃ , ZnCl ₂ , AlCl ₃ and SnCl ₄ or complexes thereof, and organometallic compounds such as triethylaluminum and diethylzinc.

The amount of catalyst varies depending on the type, but is 0 for the starting material.
It can be used in the range of 01 to 10%, preferably 0.1 to 5%.

The reaction temperature is -20 to 200 ° C, preferably 0 ° C to 120 ° C.

The reaction can also be carried out using a solvent.

A solvent having active hydrogen cannot be used as the solvent.

That is, ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, benzene, toluene,
Aromatic solvents such as xylene, ethers, aliphatic hydrocarbons, esters and the like can be used.

Now, the epoxidizing agent is allowed to act on the thus-synthesized polyether compound having a vinyl group side chain to synthesize the epoxy compound used in the foundry sand caking composition of the present invention. Examples of the epoxidizing agent include peracids and hydroperoxides.

Examples of peracids include formic acid, peracetic acid, perbenzoic acid and trifluoroperacetic acid.

Of these, peracetic acid is a preferred epoxidizing agent because it is industrially produced in large quantities, is inexpensively available, and has high stability.

Hydroperoxides include hydrogen peroxide, tertiary butyl hydroperoxide, cumene peroxide and the like.

A catalyst may be used in the epoxidation, if necessary.

For example, in the case of peracid, an alkali such as sodium carbonate or an acid such as sulfuric acid can be used as a catalyst.

Further, in the case of hydroperoxides, a mixture of tungstic acid and caustic soda is used as hydrogen peroxide, or an organic acid is used as hydrogen peroxide, or molybdenum hexacarbonyl is used as tertiary butyl hydroperoxide to obtain a catalytic effect. be able to.

The epoxidation reaction is carried out by adjusting the presence or absence of a solvent and the reaction temperature according to the physical properties of the equipment and raw materials.

The reaction temperature range that can be used depends on the reactivity of the epoxidizing agent used.

Peracetic acid, which is a preferred epoxidizing agent, is 0-
70 ° C is preferred.

If it is less than 0 ° C, the reaction is slow, and if it exceeds 70 ° C, the decomposition of peracetic acid occurs.

In the tertiary butyl hydroperoxide / molybdenum dioxide diacetylacetonate system, which is an example of hydroperoxide, 20 ° C. to 150 ° C. is preferable for the same reason.

The solvent can be used for the purpose of reducing the viscosity of the raw material and stabilizing it by diluting the epoxidizing agent.

In the case of peracetic acid, an aromatic compound, an ether, for example, in the case of peracid, an alkali such as sodium carbonate or an acid such as sulfuric acid can be used as a catalyst.

The charged molar ratio of the epoxidizing agent to the unsaturated bond can be changed according to the purpose such as the amount of the unsaturated bond to be left.

When a compound having a large number of epoxy groups is intended, the epoxidizing agent is preferably added in an equimolar amount or more with respect to the unsaturated group.

However, it is usually disadvantageous to exceed 2 times the molar amount in view of economical efficiency and side reactions, and in the case of peracetic acid, 1 to 1.5 times the molar amount is preferable.

An epoxy compound (a) obtained as a result of the above reaction is described in Japanese Patent Application No. 63-50361.

The (B) phenol formaldehyde resin (B) used in the present invention includes phenol, cresol, xylenol, paratertiarybutylphenol, catechol,
Resins obtained by condensation of formaldehyde with monophenol compounds or diphenol compounds such as resorcinol, phenylphenol, bisphenol A, bisphenol F, bisphenol S, and isopropenylphenol, and are roughly classified into novolac type phenol formaldehyde resins and resole type phenols. Classified into formaldehyde resins, any of which can be used in the present invention.

In the present invention, a curing accelerator may be used in combination to adjust the curing rate of the epoxy compound (A) (A) and the phenol formaldehyde resin (B) (B). For example, aminophenol such as dimethylaminophenol. , Diazabicycloundecene and salts thereof, for example urea derivatives such as 3 (p-chlorophenyl) -1,1-dimethylurea,
For example, urea derivatives such as amine-substituted imidazole and cyanoethyl-substituted imidazole, and organic acid dihydrazides such as succinic acid dihydrazide and adipic acid dihydrazide are used as a curing accelerator.

A second invention of the present invention other than the above invention is that (A) 4-vinylcyclohexene-1-oxide and a compound having two or more epoxy groups are subjected to addition polymerization with a compound having one or more active hydrogens. Epoxy compound obtained by epoxidizing the obtained polyether compound (a)
And (C) a curing agent (C) for the epoxy compound (B) which is inactive at room temperature, the present invention relates to a composition for caking foundry sand, wherein the third invention relates to the epoxy compound (A) ( (A), (B) phenol formaldehyde resin (b), and (C) a curing agent (c) for the epoxy compound (a) that is inactive at room temperature, and relates to a composition for caking sand. A fourth invention is (A) the epoxy compound (a), (B) a phenol formaldehyde resin (b), (C) a curing agent (c) of the epoxy compound (a) which is inactive at room temperature, D) The present invention relates to a molding sand caking composition comprising a curing agent (d) for the phenol formaldehyde resin which is inactive at room temperature.

When the foundry sand caking composition of the second invention is used as a binder, the (A) epoxy compound reacts with the curing agent of (C), but the third and fourth inventions are the same. When the foundry sand caking composition of the invention is used as a caking agent, the (A) epoxy compound (a) mainly reacts with the (C) curing agent (c) and the (B) phenol formaldehyde. The resin is self-hardening or undergoes a curing reaction with the above-mentioned (D) curing agent (D).

The (A) epoxy compound (a) and (B) phenol formaldehyde resin (b) used in the present invention are the same as those described above.

The curing agent (c) of the epoxy compound (a) that is inactive at room temperature (C) used in the present invention does not react with the epoxy compound (a) of (a) at room temperature and is short when heated. A curing agent that reacts with time, preferably a curing agent that completes the reaction with an epoxy group within a few minutes at a temperature of 150 ° C. or higher.

As such a curing agent, dicyandiamide and various dicyandiamide derivatives such as guanidine and biguanide, organic acid hydrazides such as succinic acid dihydrazide and adipic acid dihydrazide, and imidazole derivatives such as azine-substituted imidazole and cyanoethyl-substituted imidazole. Aromatic diamines such as metaphenylenediamine and diaminophenylmethane, and acid anhydrides such as trimellitic anhydride, hexahydrophthalic anhydride and methyltetrahydrophthalic anhydride. Among these hardeners which are inactive at room temperature, dicyandiamide and its derivatives, organic acid hydrazides, and imidazole derivatives are preferable from the viewpoint of core strength and heat disintegration.

The curing agent (d) for the phenol formaldehyde resin (b) that is inactive at room temperature (D) used in the present invention does not react with the phenol formaldehyde resin (b) at room temperature for a short time by heating. Is a curing agent that reacts with, preferably a curing agent that completes the reaction with the phenol resin within a few minutes at a temperature of 150 ° C. or higher.

When the phenol formaldehyde resin (b) is a resol type phenol formaldehyde resin or a mixture or a mixture of a resol type phenol formaldehyde resin and a novolac type phenol formaldehyde resin, (D) is unnecessary because it has self-hardening property. .

When the (B) phenol formaldehyde resin (B) is a novolac type phenol formaldehyde resin, the (D) curing agent (D) is used. Examples of such a curing agent include hexamethylenetetramine, triethylamine, pyridine, benzolsulfonic acid, and paratoluolsulfonic acid, and hexamethylenetetramine is preferably used.

Further, in order to accelerate the reaction rate at the time of core molding, for example, benzoic acid, acetylbenzoic acid, hydroxybenzoic acid, oxalic acid, succinic acid, paratoluenesulfonic acid, dodecylbenzenesulfonic acid, alkylphosphoric acid, and other organic acids are used to accelerate the reaction. It is also possible to use it as an agent.

The proportions of the respective components (A) to (D) of the foundry sand caking composition of the present invention are determined as follows. That is, when the total total amount of each component is 100% by weight, the total amount of (A) and (C) is 5 to 95% by weight, and the total amount of (B) and (D) is 95 to 5% by weight. However, preferably, the total amount of (A) and (C) is 30 to 70% by weight, and the total amount of (B) and (D) is 70 to 30% by weight to achieve the effect of the present invention. Good for. The optimum ratio of (A) and (C) varies depending on the curing agent of (C) and core molding conditions, but (C) with respect to the epoxy compound (A) of (A).
The amount of the curing agent (C) that is inactive at room temperature is usually 0.5 to 4.0 times equivalent, preferably 1.0 to 2.5 times equivalent, of active hydrogen groups that contribute to the reaction of the curing agent with respect to the equivalent number of epoxy groups. It may be used as follows. If the equivalence is out of this range, the core having sufficient strength may not be obtained due to curing for a short time. The blending ratio of (B) and (D) is such that when (B) is a novolac type, the total amount of (B) + (D) is 100.
When (B) is 80 to 95% by weight, (D)
Is usually used in a proportion of 20 to 5% by weight, and when (B) is a resole type or a mixture of a resole type and a novolac type or a mixed melt, (D) is not usually used.
Further, in the case of the composition for casting sand caking consisting only of (A) and (B), the hardening acceleration is slow, so when carrying out the tensile strength test, 320 ° C for 120 seconds using a shell mold high temperature tensile tester. It is necessary to mold the test piece with. Furthermore, in the heat disintegration test, it is necessary to preheat the mold to 320 ° C. to make the core. The total amount of each of the above components (A) to (D) of the casting sand caking composition of the present invention is 1 to 10% by weight with respect to silicon,
It is preferably used in an amount of 1.5 to 3% by weight. If this total amount is less than 1% by weight, sufficient strength cannot be obtained during firing molding of the mold or core, while if it exceeds 10% by weight, the strength becomes too large and the disintegration property after pouring is reduced, which is preferable. Absent.

Further, the composition for casting sand caking of the present invention has the above-mentioned (A)
In addition to the components (D) to (D), not only the above-mentioned various curing accelerators and reaction accelerators but also, for example, polyvalent epoxy resins,
Melamine resin, furan resin, urea resin, xylene resin,
Other resins such as polyester resin may be mixed within the range not impairing the object of the present invention. In addition, in order to improve the slipperiness of the resin-coated sand and to improve the adhesion between the sand and the binder, an auxiliary agent such as a silane coupling agent or a titanium coupling agent, or an inorganic filler other than silica sand. It is also possible to use together. Additives such as auxiliaries and fillers are generally added within a total amount of about 5% by weight of the composition.

In order to produce a resin-coated sand using the foundry sand caking composition of the present invention, the caking composition of the present invention is usually added to and mixed with sufficiently preheated silica sand, followed by cooling, and then the sand surface is formed. A method of fusing the binder is adopted.

The resin-coated sand obtained by the above method is blown into a mold heated to usually 150 ° C. or higher, preferably 180 ° C. to 270 ° C., and demolded after 1 minute to 3 minutes to obtain a core. .

(Examples) Next, the present invention will be described with reference to synthesis examples, examples, comparative examples, and test examples.

Synthesis Example 1 7.1 g (0.05 mol) of trimethylolpropane was dissolved in 124 g (1.0 mol) of 4-vinylcyclohexene-1-oxide, and 5.0 g of 4-vinylcyclohexene diepoxide was further dissolved.
(0.03 mol) was dissolved.

Subsequently, 2.7 g of BF ₃ etherate was added as an ethyl acetate solution to obtain 4
The solution was dropped over a period of time and reacted.

During the dropping, the inside of the system was kept at 50 ° C.

After completion of the dropping, analysis by gas chromatography confirmed that trimethylolpropane, 4-vinylcyclohexene-1-oxide and 4-vinylcyclohexene diepoxide were almost disappeared.

Subsequently, 200 g of ethyl acetate was added to the reaction crude liquid, and 300 g of pure water was added.
It was washed with water three times.

91.2g of peracetic acid in the obtained ethyl acetate solution of polyether
(1.2 mol) was added dropwise as an ethyl acetate solution over 4 hours. During the dropping, the inside of the system was kept at 50 ° C.

After further aging at 50 ° C. for 2 hours, it was washed with 300 g of pure water three times.

Then, remove low boiling components with a rotary evaporator,
An epoxy compound of Synthesis Example 1 was obtained. Table 1 shows the raw material composition, the softening temperature of the epoxy compound, and the epoxy equivalent.

Synthesis Example 2 Trimethylolpropane, 4-vinylcyclohexene-
The reaction ratios of 1-oxide and 4-vinylcyclohexene epoxide were changed as shown in Table 1, and the reaction was carried out in the same manner as in Synthesis Example 1 to obtain an epoxy compound of Synthesis Example 2. Table 1 also shows the softening temperature and the epoxy equivalent of the epoxy compound.

Synthesis Examples 3 to 4 Instead of 4-vinylcyclohexene diepoxide, 3,
4-Epoxycyclohexyl-3,4-epoxycyclohexanecarboxylate (Celoxide 2021: manufactured by Daicel Chemical Industries, Ltd.) was used in the proportions shown in Table 1 to carry out a reaction in the same manner as in Synthesis Example 1 to obtain Synthesis Examples 3 and 4 The epoxy compound of was obtained. Table 1 also shows the softening temperature and the epoxy equivalent of the epoxy compound.

Comparative Synthetic Examples 1 and 2 Using only trimethylolpropane and 4-vinylcyclohexene in the ratios shown in Table 1, the epoxy compounds of Comparative Synthetic Examples 1 and 2 were obtained in the same manner as in Synthetic Example 1. Table 1 also shows the softening temperature and the epoxy equivalent of the epoxy compound.

Example 1 Nikko No. 6 silica sand (manufactured by Kawatetsu Mining Co., Ltd.) 4 kg preheated to 250 ° C.
Was put into a speed mixer, and when it reached 130 ° C,
Phenol formaldehyde resin PS-4113 (manufactured by Gunei Chemical Industry Co., Ltd.) prepared by mixing 30 g of the epoxy compound (softening temperature 85 ° C., epoxy equivalent 165) obtained in Synthesis Example 1 premixed with a resole type and novolac type. ) 30 g, dicyandiamide 9 g, and 3 g of fine powder of imidazole derivative 2P4MHZ (manufactured by Shikoku Kasei Co., Ltd.) were added, and 1 minute later, 60 cc of water was added. Resin is melt-coated on the surface of the sand particles, and when the sand particles start blocking, add 3 g of calcium stearate and add 30
After 2 seconds, it was taken out from the speed mixer to obtain the resin-coated sand of Example 1.

Example 2 Nikko No. 6 silica sand (manufactured by Kawatetsu Mining Co., Ltd.) preheated to 250 ° C. 4 kg
Was put into a speed mixer, and when it reached 170 ° C,
48 g of the epoxy compound (softening temperature 94 ° C., epoxy equivalent 178) obtained in Synthesis Example 2 was added, and when the temperature reached 130 ° C., pre-mixed resol-type phenol formaldehyde resin PS-2176 (Guneiei) Chemical Industry Co., Ltd.
(Manufacturing, softening temperature 80 ° C.) 32 g and adipic acid dihydrazide 20 g were added, and 1 minute later, water 80 cc was added. When the surface of the sand particles was melt-coated and the sand particles started to block, 4 g of stearic acid was added and taken out from the speed mixer after 60 seconds to obtain the resin-coated sand of Example 2.

Example 3 Nikko No. 6 silica sand (manufactured by Kawatetsu Mining Co., Ltd.) preheated to 250 ° C. 4 kg
Was put into a speed mixer, and when it reached 150 ° C,
40 g of the epoxy compound (softening temperature 85 ° C., epoxy equivalent 173) obtained in Synthesis Example 3 preliminarily mixed with novolac type phenol formaldehyde resin PSM-2207 (manufactured by Gunei Chemical Industry Co., Ltd., softening temperature 80 ° C.) 40 g was added, and then at 100 ° C., 8 g of dicyandiamide and 12 g of hexamethylenetetramine were dispersed and dissolved in 40 g of water, and added and mixed. The resin was melt-coated on the surface of the sand particles, and when the sand particles started blocking, 4 g of calcium stearate was added, and after 30 seconds, the sand particles were taken out from the speed mixer to obtain the resin-coated sand of Example 3.

Example 4 4 kg of Nikko No. 6 silica sand (manufactured by Kawatetsu Mining Co., Ltd.) preheated to 250 ° C.
Was put into a speed mixer, and when it reached 170 ° C,
24 g of the epoxy compound (softening temperature 93 ° C., epoxy equivalent 176) obtained in Synthesis Example 4 was added, and when the temperature reached 130 ° C., a phenol formaldehyde resin PS4113 was prepared by mixing the resole type and the novolak type that had been mixed in advance.
(Gunei Chemical Industry Co., Ltd.) 36g and imidazole derivative 2PH
2 g of fine powder of Z (manufactured by Shikoku Kasei Co., Ltd.) was added, and 1 minute later, 60 cc of water was added. Resin is melt-coated on the surface of the sand grains, and when the sand grains start blocking, calcium stearate
After 30 seconds after adding 3 g, the resin-coated sand of Example 4 was obtained by taking out from the speed mixer.

Example 5 Nikko No. 5 silica sand (manufactured by Kawatetsu Mining Co., Ltd.) 4 kg preheated to 250 ° C.
Was charged into a speed mixer, and when the temperature reached 150 ° C, 36 g of the epoxy compound (softening temperature 85 ° C, epoxy equivalent 165) obtained in Synthesis Example 1 was charged, and then mixed at 130 ° C in advance. Oita novolac type phenol formaldehyde resin PSM-2207 (Gunei Chemical Industry Co., Ltd.)
Made, softening temperature 80 ℃) 24g and imidazole derivative 2P4MHZ
3 g of fine powder (manufactured by Shikoku Kasei Co., Ltd.) was added, and 1 minute later, 60 cc of water was added. Resin is melt-coated on the surface of the sand grains, and when the sand grains start blocking, calcium stearate 3 g
After 30 seconds from the addition of the above, the resin-coated sand of Example 5 was obtained by taking out from the speed mixer.

Comparative Example 1 Nikko No. 6 silica sand (manufactured by Kawatetsu Mining Co., Ltd.) preheated to 250 ° C 4 kg
Was charged into a speed mixer, and when the temperature reached 130 ° C., 30 g of the epoxy compound (softening temperature 70 ° C., epoxy equivalent 179) obtained in Comparative Synthesis Example 1, which had been mixed in advance, was mixed with the resole type and novolak type. 30 g of phenol formaldehyde resin PS4113 (manufactured by Gunei Chemical Industry Co., Ltd.), 9 g of dicyandiamide and 3 g of fine powder of imidazole derivative 2P4MHZ (manufactured by Shikoku Kasei Co., Ltd.) were added, and 1 minute later, 60 cc of water was added. Resin is melt-coated on the surface of the sand particles, and when the sand particles start blocking, add 3 g of calcium stearate and add 30
After a second, it was taken out by a speed mixer to obtain a resin-coated sand of Comparative Example 1.

Comparative Example 2 4 kg of Nikko No. 6 silica sand (manufactured by Kawatetsu Mining Co., Ltd.) preheated to 250 ° C
Was added to a speed mixer, and 30 g of the epoxy compound (softening temperature 74 ° C., epoxy equivalent 177) obtained in Comparative Synthesis Example 2 premixed at 130 ° C. and resol type phenol formaldehyde resin PS-2176 30 g (manufactured by Gunei Chemical Industry Co., Ltd., softening temperature 80 ° C.) and 9 g of dicyandiamide were added, and 1 minute later, 60 cc of water was added. Resin was melt-coated on the surface of the sand particles, and when the sand particles started blocking, 3 g of calcium stearate was added as a lubricant, and after 30 seconds, the mixture was taken out from the speed mixer to obtain resin-coated sand of Comparative Example 2.

Comparative Examples 3 to 5 Resin-coated sands of Comparative Examples 3 to 5 were obtained in the same manner as in Comparative Example 2 except that the lubricant was used. The compounding ratio of the lubricant is shown in Table 2.

Example 6 4 kg of Nikko No. 6 silica sand (manufactured by Kawatetsu Mining Co., Ltd.) preheated to 250 ° C.
Was put into a speed mixer, and when it reached 130 ° C,
60 g of the epoxy compound (softening temperature 85 ° C., epoxy equivalent 165) obtained in Synthesis Example 1 and 9 g of dicyandiamide, which had been mixed in advance, were added, and 1 minute later, 60 cc of water was added. Resin is melt coated on the surface of the sand grains, and when the sand grains start blocking, add 3 g of calcium stearate as a lubricant and add 30
It was taken out from the speed mixer every second, and the resin-coated sand of Example 6 was obtained.

Example 7 Nikko No. 6 silica sand (manufactured by Kawatetsu Mining Co., Ltd.) preheated to 250 ° C. 4 kg
Was put into a speed mixer, and when it reached 150 ° C,
60 g of the epoxy compound (softening temperature 94 ° C., epoxy equivalent 178) obtained in Synthesis Example 2 was added at the time of 130 ° C., and 9 g of dicyandiamide and 3 g of fine powder of imidazole derivative 2P4MHZ (manufactured by Shikoku Kasei Co., Ltd.) were added. After 1 minute, 60 cc of water was added. Resin is melt-coated on the surface of the sand grains, and calcium stearate is used as a lubricant when the sand grains start blocking.
After 3 g was added and 30 seconds later, it was taken out from the speed mixer to obtain the resin-coated sand of Example 7.

Example 8 4 kg of Nikko No. 5 silica sand (manufactured by Kawatetsu Mining Co., Ltd.) preheated to 250 ° C.
Was charged into a speed mixer, and when the temperature reached 170 ° C, 60 g of the epoxy compound (softening temperature 85 ° C, epoxy equivalent 173) obtained in Synthesis Example 3 was added, and when 140 ° C, 15 g of adipic acid dihydrazide was added. After 1 minute, 60 cc of water was added. 3 g of calcium stearate as a lubricant when the sand particles start to block and the resin is melt-coated on the surface of the sand particles.
In addition, after 60 seconds, it was taken out from the speed mixer to obtain the resin-coated sand of Example 8.

Example 9 4 kg of Nikko No. 6 silica sand (manufactured by Kawatetsu Mining Co., Ltd.) preheated to 250 ° C.
Was charged into a speed mixer, and 60 g of the epoxy compound (softening temperature 93 ° C., epoxy equivalent 176) obtained in Synthesis Example 4 and 9 g of dicyandiamide, which had been mixed in advance when the temperature reached 150 ° C., were charged, and 1 minute later 60 cc of water was added. Resin is melt-coated on the surface of the sand grains, and when the sand grains start blocking, add 3 g of calcium stearate as a lubricant and add 60
After seconds, the resin-coated sand of Example 9 was obtained by taking out from the speed mixer.

Example 10 A resin-coated sand of Example 10 was obtained in the same manner as in Example 5, except that the fine powder of the imidazole derivative was not used.

Comparative Example 6 Nikko No. 6 silica sand (manufactured by Kawatetsu Mining Co., Ltd.) preheated to 250 ° C. 4 kg
Was added to a speed mixer, and 60 g of the epoxy compound (softening temperature 70 ° C., epoxy equivalent 179) obtained in Comparative Synthesis Example 1 premixed at 130 ° C. and 9 g of dicyandiamide were added, and 1 minute later 60 cc of water was added. Resin is melt-coated on the surface of the sand particles, and when the sand particles start blocking, add 3 g of calcium stearate as a lubricant.
After 30 seconds, it was taken out from the speed mixer to obtain a resin-coated sand of Comparative Example 6.

Comparative Example 7 Nikko No. 6 silica sand (manufactured by Kawatetsu Mining Co., Ltd.) preheated to 250 ° C. 4 kg
Was added to a speed mixer, 60 g of the epoxy compound obtained in Comparative Synthesis Example 2 (softening temperature 74 ° C., epoxy equivalent 177) and 9 g of dicyandiamide, which had been mixed in advance at 130 ° C., were added, and 1 minute later 60 cc of water was added. Resin is melt-coated on the surface of the sand particles, and when the sand particles start blocking, add 3 g of calcium stearate as a lubricant.
After 30 seconds, it was taken out from the speed mixer to obtain a resin-coated sand of Comparative Example 7.

Comparative Examples 8 to 10 Resin-coated sands of Comparative Examples 8 to 10 were obtained in the same manner as in Comparative Example 7 except that the lubricant was used. The compounding ratio of the lubricant is shown in Table 2.

Test Example <Fusing Point> Measurement was performed according to “JACT (Foundry Technology Promotion Association) Test Method C-1”. The results obtained are also shown in Table 2.

<Tensile Strength Test> With respect to the resin-coated sand produced in Examples 1 to 9 and Comparative Examples 1 to 10, test pieces were molded at 250 ° C. for 60 seconds using a shell mold high temperature tensile tester. Also, for Example 10, 320
A test piece was molded at 120 ° C for 120 seconds. After cooling to room temperature, a tensile test was performed to measure tensile strength. The results obtained are also shown in Table 2.

<Thermal disintegration test> In this test, first, the resin-coated sands obtained in Examples 1 to 9 and Comparative Examples 1 to 10 were poured into a mold preheated to 250 ° C., and the core 1 (upper part) shown in FIG. : Diameter 10mm x Length 20mm,
Lower part: diameter 50 mm x length 30 mm) was prepared. Example 10
For, the core 1 was prepared by pouring it into a mold preheated to 320 ° C. Then, as shown in Fig. 2, inside diameter 100m
The core mounting jig 3 has a lower end of the core 1 at a position 10 mm above the bottom of the metal melting crucible 2 having a recess of m and a depth of 70 mm and is located at the center of the metal melting crucible 2. To fix core 1. Then, 700 ° C AC2A molten aluminum 4 was poured up to 10 mm below the upper end of the core. After solidification and cooling, the jig 3 was removed from the core 1, and then the casting was taken out from the metal melting crucible 2. The casting thus obtained is fixed to a jig for a low-tap tester with the upper part of the core facing downward, and shock-vibrated by a low-tap tester manufactured by Tokuju Seisakusho Co., Ltd., resulting in collapse of the upper part of the core. The amount of sand discharged from the discharge port was measured, and the thermal disintegration property was determined by the ratio with the initial core weight. Impact vibration time is 1 minute, 3 minutes, 5
Minutes and 10 minutes were measured cumulatively. The results obtained are also shown in Table 2.

<Evaluation of Gas Defects> The castings obtained in the above thermal disintegration test were cut, and the presence or absence of gas defects inside the castings was visually evaluated. The results obtained are also shown in Table 2.

(Effect of the invention) As described above, when the composition for casting sand caking of the present invention is used,
Compared with Comparative Example 1 and Comparative Examples 3 to 11, since the composition for casting sand caking, especially the epoxy compound has a high softening temperature, the composition for casting sand caking and the blocking of resin-coated sand even under high temperature in summer Is hard to wake up. Therefore, it is not necessary to use an antiblocking agent or to increase the amount of lubricant when manufacturing the resin-coated sand. As in Comparative Examples 4 to 6 and 9 to 11, the fusion point for increasing the amount of lubricant is high, but the tensile strength is poor.

On the other hand, in Comparative Example 2, since the epoxy compound having a higher softening temperature as compared with Comparative Examples 1 and 3 was used, the fusion points are almost the same as those in Examples 1 to 5, and the above-mentioned problems occur. Solvable. Although it has a higher thermal disintegration property than Examples 1 to 5, on the other hand, gas defects may occur depending on the shape of the casting, the casting conditions, and the like. However, each Example 1
No gas defect occurs in the evaluations of ˜5. As described above, in Examples 1 to 5, a phenol resin was mixed in order to improve the problem of gas generation, and the gas defects are reduced, but the disintegration is slightly inferior. On the other hand, in Examples 6 to 9, the disintegration was emphasized, the phenol resin was not contained, and the thermal decomposability was sufficient, so that a large amount of gas was generated and there was a problem of gas defects. However, as is clear from Examples 1 to 9, the foundry sand caking composition of the present invention has excellent properties such as tensile strength, which are conventionally possessed, and is also excellent in thermal disintegration. It is clear that the effect of the present invention as a binder for a mold of a low melting point casting such as an aluminum alloy or a core is very large.

[Brief description of drawings]

FIG. 1 is a perspective view of a core used for a thermal collapse test and gas defect evaluation. FIG. 2 is a cross-sectional view of a casting device for a thermal collapse test and gas defect evaluation. 1 ... core, 2 ... crucible for melting metal 3 ... jig for core mounting, 4 ... molten aluminum

Claims (5)

[Claims] 1. A epoxidized polyether compound obtained by addition-polymerizing (A) 4-vinylcyclohexene-1-oxide and a compound having two or more epoxy groups with a compound having one or more active hydrogens. A composition for caking foundry sand, which comprises the epoxy compound (a) thus obtained and (B) a phenol formaldehyde resin (b). 2. A molding sand caking composition comprising (A) the epoxy compound (a) according to claim 1 and (C) a curing agent (c) which is inert at room temperature. 3. An epoxy compound (a) according to claim 1, (B) a phenol formaldehyde resin (b), and (C) a curing agent (c) which is inert at room temperature. A composition for caking foundry sand, which comprises: 4. The composition for casting sand-bonding according to claim 3, wherein the phenol formaldehyde resin (b) is a resol type phenol formaldehyde resin, or a mixture or mixed melt of a resol type phenol formaldehyde resin and a novolac type phenol formaldehyde resin. . 5. (A) The epoxy resin (a) according to claim 1.
And (B) a phenol-formaldehyde resin (B), (C) a curing agent (C) which is inert at room temperature (C), and (D) a curing agent (D) described above (B) Sand caking composition.