WO2018043412A1

WO2018043412A1 - Casting mold manufacturing method

Info

Publication number: WO2018043412A1
Application number: PCT/JP2017/030764
Authority: WO
Inventors: 智宏高間; 哲也浦
Original assignee: 旭有機材株式会社
Priority date: 2016-08-31
Filing date: 2017-08-28
Publication date: 2018-03-08
Also published as: JP6923533B2; JPWO2018043412A1; CN109641265B; CN109641265A; MX2019002260A; WO2018043412A8

Abstract

Provided is a casting mold manufacturing method that is capable of effectively improving workability at a molding site while improving coated sand fillability and casting mold strength. Provided is a method that is capable of advantageously manufacturing an intended casting mold by using a conventional molding device as is without any need to newly install a special device. The intended casing mold is formed by adding an aqueous medium prepared by including a surfactant and/or a polyhydric alcohol in dry-state coated sand obtained by covering the surface of a refractory aggregate with a water-soluble binder, moistening the coated sand, and then filling a molding die with the obtained moist coated sand.

Description

Mold manufacturing method

The present invention relates to a mold manufacturing method, and in particular, while improving workability at a molding site, which is a mold manufacturing site, advantageously manufactures the mold and improves the filling property of the coated sand and the strength of the mold. It is about the method that can be made to.

Conventionally, as one of the methods for producing a mold used for casting a molten metal, a coated sand formed by coating a mold sand made of a refractory aggregate with a predetermined binder is used. A technique for forming a mold has been adopted, and as a binder used there, for example, “Casting Engineering Handbook” pages 78 to 90 edited by the Japan Foundry Engineering Society include inorganic systems such as water glass. In addition to binders, organic binders using resins such as phenolic resins, furan resins, and urethane resins have been clarified, and in these cases, self-hardening molds are formed using these binders. The method is also clarified.

And after forming the coated sand which coat | covers a predetermined | prescribed fireproof aggregate (mold sand) using water glass which is one of the inorganic binders among these binders, mold making Various methods have also been proposed as a method for performing the above. For example, in Japanese Unexamined Patent Application Publication No. 2008-036712, silica sand (refractory aggregate), alkali silicate (water glass), and amorphous dioxide. A mold material or mold part containing an agglomerate containing silicon has been identified. In addition, there, the silica sand, water glass and amorphous silicon dioxide are kneaded at the mold making site, and wet alkali silicate (water glass) is adhered to the surface of the silica sand. A mold material (coated sand) in a wet form (humid state) is formed, and the mold material is filled into a predetermined mold to form a mold having a desired shape.

However, such wet coated sand reacts with carbon dioxide in the air and gradually cures, so the pot life is short and the storage stability is not sufficient. Such a wet coated sand is generally manufactured at a molding site of a mold and then filled in a molding die as it is to perform the molding of a target mold. Therefore, in order to obtain a wet coated sand by transporting fine powdery refractory aggregate and water glass to a molding site with many obstacles and kneading them with a mixer, the viscosity of water glass is high. In addition, it takes a lot of labor and time, and in addition to the difficulty of mixing with refractory aggregate due to the viscosity of water glass, mixing mixers and molds for molding, etc. There is a problem of poor workability in molding, such as the equipment is easily soiled. In addition, since the work is performed at the molding site, there is an inherent problem that the worker is highly likely to receive chemical injury due to the strong alkaline water glass.

On the other hand, unlike the wet coated sand as described above, water glass is used as a binder, and a coating layer in which such a binder is dried is formed on the surface of the refractory aggregate. JP-A-2012-076115 discloses a dry coated sand having room temperature fluidity. There, such dry coated sand is coated with a solid coating layer containing a water-soluble inorganic compound such as water glass as a binder, which is used to mold a mold for mold making. After filling the cavity, the method of solidifying the coated sand by aeration of water vapor and obtaining the target mold has been clarified. It is necessary to blow water vapor into the mold after filling with the dry coated sand. Therefore, it is necessary to specially provide a water vapor blowing device, so that the conventional device can be used as it is. There are inherent problems that cannot be achieved and increase the manufacturing cost of the mold.

Moreover, the wet coated sand filled in the mold is wetted with water vapor and then solidified by drying to mold the mold, so that the wet coated sand is used. In order to effectively dry the sand, it is necessary to add a new process of blowing a heated gas in addition to blowing water vapor, thereby forming a mold from filling into a mold to drying solidification or curing. The problem is that the cycle becomes longer and the productivity of the mold decreases.

JP 2008-036712 A JP 2012-076115 A

Here, the present invention has been made against the background of such circumstances, and the solution is to improve the workability at the molding site while improving the filling property of the coated sand and the strength of the mold. It is to provide a mold manufacturing method capable of effectively achieving the above, and another problem is that a conventional apparatus for molding is basically left as it is without installing a special apparatus. The object of the present invention is to provide a method capable of advantageously producing a target mold.

In order to solve the above-described problems, the present invention can be suitably implemented in various aspects as listed below, and each aspect described below is employed in any combination. Is possible. It should be noted that aspects or technical features of the present invention are not limited to those described below, and can be recognized based on the inventive concept that can be grasped from the description of the entire specification. Should be understood.

(1) An aqueous medium containing a surfactant and / or a polyhydric alcohol is added to dry coated sand obtained by coating the surface of a refractory aggregate with a water-soluble binder. A method for producing a casting mold, comprising: moistening and then filling the obtained wetted coated sand into a molding die.
(2) The aqueous medium is 100 parts by mass of the coated sand,
The method for producing a mold according to the aspect (1), wherein the mold is added to the coated sand in a ratio of 0.5 to 6 parts by mass.
(3) The aqueous medium is added so that the surfactant has a ratio of 0.1 to 20.0 parts by mass with respect to 100 parts by mass of the solid content of the water-soluble binder in the coated sand. The above aspect (
A method for producing a mold according to 1) or aspect (2).
(4) The aqueous medium is added so that the polyhydric alcohol has a ratio of 0.1 to 20.0 parts by mass with respect to 100 parts by mass of the solid content of the water-soluble binder in the coated sand. The method for producing a mold according to any one of the above aspects (1) to (3), wherein:
(5) The aspect (1) to the aspect (4), wherein spherical particles are further added to wet the dry coated sand.
The manufacturing method of the casting_mold | template as described in any one of these.
(6) The aspect (5), wherein the addition amount of the spherical particles is 0.1 to 20.0 parts by mass with respect to 100 parts by mass of the solid content of the water-soluble binder in the coated sand. The method for producing a mold as described in 1).
(7) The aspect (1), wherein a second water-soluble binder is further added to wet the dry coated sand.
Thru | or the manufacturing method of the casting_mold | template as described in any one of the said aspect (6).
(8) The above aspect (5), wherein the moisture content in the dry coated sand is 5 to 55% by mass of the solid content of the water-soluble binder.
1) The manufacturing method of the casting_mold | template as described in any one of the said aspect (7).
(9) The above aspect (1), wherein one or more of thermosetting resins, saccharides, proteins, synthetic polymers, salts and inorganic polymers are selected and used as the water-soluble binder. The method for producing a mold according to any one of aspects (8) to (8).
(10) The above aspect wherein the inorganic polymer is water glass (
The method for producing a mold according to 9).
(11) In any one of the above aspects (1) to (10), heated air or dry air is ventilated in a mold filled with the wetted coated sand. A method for producing the mold described above.
(12) In any one of the above aspects (1) to (11), the carbon dioxide gas or the organic ester gas is aerated in a mold filled with the wetted coated sand. A method for producing the mold described above.
(13) The mold manufacturing method according to any one of the aspects (1) to (12), wherein the mold is heated to a temperature of 40 ° C. to 250 ° C.

As described above, in the present invention, using a water-soluble binder such as water glass as a binder, first, a dry coated sand is prepared in advance, and it is brought to the molding site, At the site of molding, it is possible to mold a target mold only by preparing a surfactant and / or a polyhydric alcohol-containing aqueous medium for moistening such dry coated sand. In the molding site where the working environment is poor, there is no need to knead the viscous water glass into the refractory aggregate, so that the workability at the molding site can be remarkably improved. In addition, even if the mixture is wetted by adding a surfactant and / or a polyhydric alcohol-containing aqueous medium to dry coated sand in the mixer, the mixture adheres to the mixer. In addition to the fact that the device is less likely to get dirty and the water-soluble binder such as water glass is not handled at the molding site, the operator can use the water glass or other water-soluble binders to burn chemicals. The fear of receiving was completely eliminated.

In addition, a surfactant and / or a polyhydric alcohol is added to the aqueous medium used for moistening the coated sand, thereby advantageously improving the filling property of the coated sand during mold making. In addition, the feature that the strength of the obtained mold can be effectively improved can be advantageously exhibited.

In addition, in the present invention, the dry coated sand prepared in advance hardly changes with time due to carbon dioxide gas in the air unless an aqueous medium is added, and the dry coated sand is excellent in storage stability. The coated sand of the state is prepared in advance in a large amount at a place different from the molding site, and at the molding site, a part thereof is added to the surfactant and / or polyhydric alcohol-containing aqueous medium, It has the practical advantage that the target mold can be molded after it has been wetted, and such dry coated sand that has been wetted can be used on the molding site as before. Compared with the wet coated sand to be produced, it exhibits excellent characteristics that the filling property into the mold is better and the mold release property of the molded mold is improved.

Furthermore, according to the method for producing a mold according to the present invention, a surfactant and / or a polyhydric alcohol-containing aqueous solution can be obtained by simply filling a mold with wetted sand and heating it at the molding site. Since the moisture of the medium is evaporated and dried or solidified or hardened, it is necessary to newly install special devices such as a water vapor generating device and a water vapor ventilation mechanism as in the case of using the dry coated sand as it is. Basically, it becomes possible to perform molding using the conventional apparatus as it is, and this can avoid an increase in apparatus cost and, in turn, an increase in mold manufacturing cost, There is no need to adopt a new steam blowing process, which can advantageously avoid lengthening the molding cycle. And than it was.

It is a front schematic diagram which shows one mold split surface of the metal mold | die half which comprises the shaping | molding die used for evaluation of filling property and filling fluidity | liquidity.

By the way, in the mold manufacturing method according to the present invention, a dry coated sand prepared in advance is generally mixed with a water-soluble binder in a state of an aqueous solution as a binder to a refractory aggregate, and By evaporating water from the mixture, in other words, by evaporating water in the water-soluble binder in the form of an aqueous solution, a dried coating layer made of a solid content of the water-soluble binder that is a binder is obtained. It is a dry product formed on the surface of such a refractory aggregate at a predetermined thickness, and has good room temperature fluidity. In particular, in the present invention, the water content in such dry coated sand is desirably 5 to 55% by mass, preferably 10 to 50%, based on the solid content of the water-soluble binder. It is desirable that it is mass%. In particular, when the water-soluble binder is water glass, the content is desirably 20 to 50% by mass. When the water content is less than 5% by mass, there is a problem that a water-soluble binder such as water glass is vitrified and does not return to a solution state even when water is added again. If the amount is larger than that, a problem of not being in a dry state occurs.

Here, in the dry coated sand used in the present invention, the range of the amount of water that gives the dry state varies depending on the nature of the water-soluble binder. For this reason, the dry state in the present invention refers to the one in which the measured value of the dynamic angle of repose is obtained when the dynamic angle of repose is measured regardless of the water content. The dynamic angle of repose means that coated sand is contained in a cylinder whose one end in the axial direction is closed with a transparent plate (for example, in a container having a diameter of 7.2 cm and a height of 10 cm. Coated sand is put to half of the volume), the core is held in the horizontal direction, and is rotated around the horizontal axis at a constant speed (for example, 25 rpm), so that the coated is flowing in the cylinder. The slope of the sand layer is a flat surface, and the angle formed between the slope and the horizontal plane is measured. On the other hand, when the coated sand is in a wet state, the coated sand layer does not flow, the slope of the coated sand layer is not formed as a flat surface, and the dynamic angle of repose cannot be measured is referred to as wet coated sand. I will do it.

In the present invention, by using the dry coated sand as described above, the pot life is prolonged, and the storage stability can be advantageously improved. In a place such as a factory that is different from the site, it is possible to prepare a large amount in advance, transport a part of it to the molding site, and use it for molding the target mold, This can greatly contribute to the efficiency of molding work.

The fireproof aggregate constituting the coated sand as described above is a fireproof material that functions as a base material of a mold, and various fireproof granular or powder materials conventionally used for molds. Can be used, specifically, silica sand, recycled silica sand, special sand such as alumina sand, olivine sand, zircon sand, chromite sand, ferrochrome slag, ferronickel slag, converter slag Slag-based particles such as alumina; artificial particles such as alumina-based particles and mullite-based particles; and regenerated particles thereof; alumina balls, magnesia clinker, and the like. These refractory aggregates may be fresh sand, or reclaimed sand or recovered sand that has been used once or a plurality of times as casting sand for casting molds. Even mixed sand made by adding fresh sand to sand or recovered sand and mixing them can be used. Such a refractory aggregate is generally used with a particle size of about 40 to 130, preferably about 60 to 110 in terms of AFS index.

In addition, the binder that covers the fireproof aggregate as described above is also called a binder, and a water-soluble binder is used in the present invention. As the water-soluble binder, any of inorganic polymers, thermosetting resins, saccharides, synthetic polymers, salts, and proteins can be used as long as they are water-soluble. These may be used alone, or two or more may be selected and used, but it is particularly preferable to use an inorganic polymer. Moreover, these water-soluble binders may be used by diluting with water or a solvent in advance.

And examples of the inorganic polymer used as such a water-soluble binder include water glass, colloidal silica, alkyl silicate, bentonite, cement, etc. Among them, water glass is preferably used. Become. Such water glass is a soluble silicate compound. Examples of such a silicate compound include sodium silicate, potassium silicate, sodium metasilicate, potassium metasilicate, lithium silicate, and ammonium silicate. In particular, in the present invention, sodium silicate (sodium silicate) is advantageously used.

Further, such sodium silicates are usually classified and used as No. 1 to No. 5 depending on the molar ratio of SiO ₂ / Na ₂ O. Specifically, sodium silicate No. 1 has a SiO ₂ / Na ₂ O molar ratio of 2.0 to 2.3, and sodium silicate No. 2 is SiO ₂ / Na ₂ O ₂ The molar ratio is 2.4 to 2.6, and sodium silicate No. 3 has a SiO ₂ / Na ₂ O molar ratio of 2.8 to 3.3. In addition, sodium silicate No. 4 has a SiO ₂ / Na ₂ O molar ratio of 3.3 to 3.5, and sodium silicate No. 5 has a SiO ₂ / Na ₂ O molar ratio. Is 3.6 to 3.8. Among these, sodium silicate Nos. 1 to 3 are also defined in JIS-K-1408. These sodium silicates may be used alone or in combination, and the molar ratio of SiO ₂ / Na ₂ O can be adjusted by mixing.

In order to advantageously obtain the dry coated sand used in the present invention, the sodium silicate constituting the water glass used as the binder generally has a SiO ₂ / Na ₂ O molar ratio of 1.9 or more. Preferably, it is 2.0 or more, more preferably 2.1 or more. In the above-mentioned classification of sodium silicate, sodium silicate corresponding to No. 1 and No. 2 is particularly advantageously used. Become. Such sodium silicates No. 1 and No. 2 provide dry coated sand having stable and good characteristics even when the sodium silicate concentration in the water glass is wide. Further, the upper limit of the SiO ₂ / Na ₂ O molar ratio in such sodium silicate is appropriately selected according to the characteristics of the water glass in the form of an aqueous solution, but generally 3.5 or less, It is preferably 3.2 or less, more preferably 2.7 or less. Here, when the SiO ₂ / Na ₂ O molar ratio is smaller than 1.9, the viscosity of the water glass is lowered, and unless the water content is considerably reduced, it becomes difficult to obtain a dry state. On the other hand, when it exceeds 3.5, the solubility in water is lowered, and the adhesion to the surface of the refractory aggregate is not sufficient, so that the adhesion area cannot be obtained and the mold strength is lowered.

The water glass used in the present invention means a solution of a silicate compound in a state dissolved in water. In addition to being used in a stock solution as purchased in the market, water is added to such a stock solution. It is added and used in a diluted state. A solid content (water glass component) obtained by removing a volatile substance such as water or a solvent from such water glass is referred to as a nonvolatile content, and this corresponds to the above-described soluble silicate compound such as sodium silicate. To do. Moreover, the higher the proportion of such non-volatile content (solid content), the higher the silicate compound concentration in the water glass. Therefore, the non-volatile content of the water glass used in the present invention corresponds to the ratio excluding the amount of water in the stock solution when it is composed of only the stock solution, while the stock solution is converted into water. When the diluted solution obtained by dilution is used, the remaining amount excluding the amount of water in the stock solution and the amount of water used for dilution corresponds to the non-volatile content of the water glass used. Will be.

The non-volatile content in the water glass is set to an appropriate ratio depending on the type of the water glass component (soluble silicate compound) and the like, but is preferably a ratio of 20 to 50% by mass. It is desirable to be contained in By making the water glass component corresponding to this non-volatile content appropriately in the aqueous solution, the water glass component can be uniformly and uniformly applied to the fire resistant aggregate during mixing (kneading) with the fire resistant aggregate. So that the intended mold can be advantageously made according to the invention. In addition, when the concentration of the water glass component in the water glass becomes too low and the total amount of non-volatile components is less than 20% by mass, the heating temperature is increased or the heating time is lengthened for drying the coated sand. For this reason, problems such as energy loss are caused. In addition, if the proportion of non-volatile content in the water glass becomes too high, it becomes difficult to uniformly coat the surface of the refractory aggregate with the water glass component, which causes a problem in improving the properties of the target mold. Therefore, it is desirable to prepare water glass in the form of an aqueous solution so that the non-volatile content is 50% by mass or less, and thus the water content is 50% by mass or more.

By the way, as a thermosetting resin which is one of the water-soluble binders other than the above-described inorganic polymer, resol type phenol resin, furan resin, water-soluble epoxy resin, water-soluble melamine resin, water-soluble urea resin, water-soluble resin Examples thereof include unsaturated polyester resins and water-soluble alkyd resins. It is also advantageous to add a curing agent such as acid or ester to the thermosetting resin to improve its thermosetting characteristics. Among these thermosetting resins, the use of a resol type phenol resin is preferable, and such a phenol resin can be prepared by reacting phenols with formaldehyde in the presence of a reaction catalyst. . Moreover, in this invention, a water-soluble alkaline resole resin is mentioned as a suitable thing as this phenol resin. When such an alkali resol resin is used, a mold that can be used in a wide range of fields such as cast iron and cast steel can be provided.

Moreover, as saccharides which are other ones of water-soluble binders, known ones such as monosaccharides, oligosaccharides and polysaccharides can be used. Among various monosaccharides, oligosaccharides and polysaccharides, 1 There is no problem even if a species is selected and used alone or a plurality of species are used in combination. Among them, examples of monosaccharides include glucose (glucose), fructose (fructose), galactose, and examples of oligosaccharides include maltose (malt sugar), sucrose (sucrose), lactose (lactose), cellobiose, and the like. Can be mentioned. Examples of the polysaccharide include starch sugar, dextrin, xanthan gum, curdlan, pullulan, cycloamylose, chitin, cellulose, and starch. In addition, gums of plant mucilage such as gum arabic may be used, and carboxylic acid can also be used as a curing agent for saccharides, particularly polysaccharides.

Furthermore, synthetic polymers used as water-soluble binders include polyethylene oxide, poly-α-hydroxyacrylic acid, acrylic acid copolymers, acrylic ester copolymers, methacrylic ester copolymers, polyacrylamide , Anionized polyacrylamide, cationized polyacrylamide, polyaminoalkyl methacrylate, acrylamide / acrylic acid copolymer, polyvinyl sulfonic acid, polystyrene sulfonic acid, sulfonated maleic acid polymer, polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene glycol, polyvinyl methyl ether , Polyether-modified silicone, or modified products thereof. And these are used independently, or a plurality are selected and used.

Furthermore, as the salts, those which are solidified by adding water and drying are used, for example, sulfates such as magnesium sulfate and sodium sulfate, bromides such as sodium bromide and potassium bromide, sodium carbonate and carbonate. Examples thereof include carbonates such as potassium, and chlorides such as barium chloride, sodium chloride and potassium chloride. In addition, examples of proteins include gelatin and glue.

The water-soluble binder as described above may be used at a ratio of 0.1 to 2.5 parts by mass in terms of solid content when considered as only a non-volatile content with respect to 100 parts by mass of the refractory aggregate. Desirably, among these, a ratio of 0.2 to 2.0 parts by mass is particularly advantageously employed, and a predetermined coating layer is formed on the surface of the refractory aggregate. Here, the measurement of solid content is implemented as follows. That is, 10 g of a sample was weighed and contained in an aluminum foil dish (length: 90 mm, width: 90 mm, height: 15 mm), placed on a heating plate maintained at 180 ± 1 ° C., and left for 20 minutes. The sample pan is inverted and left on the heating plate for an additional 20 minutes. Next, the sample dish is taken out from the heating plate, allowed to cool in a desiccator, weighed, and the solid content (% by mass) is calculated by the following formula.
Solid content (mass%) = [mass after drying (g) / mass before drying (g)]
× 100

If the amount of the water-soluble binder used is too small, it is difficult to form a coating layer on the surface of the refractory aggregate, resulting in a problem that the coated sand is not sufficiently solidified or hardened. Even if the amount of the water-soluble binder used is excessive, the water-soluble binder is excessively adhered to the surface of the refractory aggregate, making it difficult to form a uniform coating layer, and the coated sand is mutually attached. There is also a risk that it will stick and agglomerate (composite particles), which will adversely affect the physical properties of the mold and cause problems that make it difficult to remove the sand from the core after casting the metal.

In the present invention, dry coated sand obtained by using the above-mentioned water-soluble binder and forming a coating layer on the surface of the refractory aggregate is intended. In such a coating layer, a known additive can be appropriately contained as required. In order to incorporate such an additive in the coating layer, a method of kneading or mixing with a refractory aggregate after blending a predetermined additive in a water-soluble binder in advance, separately from the water-soluble binder A method of adding a predetermined additive to the refractory aggregate and kneading or mixing the whole together with the water-soluble binder is employed.

As one of such additives, in the present invention, a solid oxide or salt is advantageously used. By containing these solid oxides and salts, the moisture resistance of the coated sand can be advantageously improved. Of these, as the solid oxide, it is effective to use oxides of elements such as silicon, zinc, magnesium, aluminum, calcium, lead, boron, and the like. In particular, among these, use of silicon dioxide, zinc oxide, aluminum oxide, and boron oxide is desirable. Of silicon dioxide, precipitated silicic acid and exothermic silicic acid are preferably used. On the other hand, as the salt, there are silicofluoride, silicate, phosphate, borate, tetraborate, carbonate, etc. Among them, zinc carbonate, basic zinc carbonate, potassium metaborate, tetraborate, etc. Use of sodium acid and potassium tetraborate is desirable. These solid oxides and salts are generally used at a ratio of about 0.5 to 5% by mass with respect to the nonvolatile content in the water-soluble binder.

In addition, it is also effective to include a coupling agent that strengthens the bond between the refractory aggregate and the water-soluble binder as other additives, for example, silane coupling agents, zircon coupling agents, titanium coupling agents. Etc. can be used. It is also effective to contain a lubricant that contributes to improving the flowability of the coated sand. For example, waxes such as paraffin wax, synthetic polyethylene wax, and montanic acid wax; stearic acid amide, oleic acid amide, erucic acid amide, etc. Fatty acid amides; alkylene fatty acid amides such as methylene bis stearic acid amide and ethylene bis stearic acid amide; stearic acid, stearyl alcohol; stearic acid metal salts such as lead stearate, zinc stearate, calcium stearate, magnesium stearate; stearin Acid monoglycerides, stearyl stearate, hydrogenated oils and the like can be used. Furthermore, as release agents, paraffin, wax, light oil, machine oil, spindle oil, insulating oil, waste oil, vegetable oil, fatty acid ester, organic acid, fine graphite particles, mica, meteorite, fluorine release agent, silicone release agent An agent or the like can also be used. Each of these other additives is generally contained in a proportion of 5% by mass or less, preferably 3% by mass or less, with respect to the nonvolatile components in the water-soluble binder.

By the way, in the present invention, when manufacturing a dry coated sand prepared in advance, generally, a water-soluble binder as a binder is added to the fire-resistant aggregate, together with additives used as necessary. By kneading or mixing according to a conventional method, mixing uniformly, and covering the surface of such a refractory aggregate with a water-soluble binder, and by evaporating the water of such a water-soluble binder, A method of obtaining dry powdered coated sand having room temperature fluidity will be adopted, but the transpiration of the moisture in the coating layer at that time is quickly before solidification or hardening of the water-soluble binder proceeds Therefore, in the present invention, it is more preferable that the water-resistant binder in the form of an aqueous solution is added (mixed) to the refractory aggregate within 5 minutes. Is properly within 3 minutes, skip-containing water, it is desirable that the powder coated sand of Inuitai. If the transpiration time becomes longer, the mixing (kneading) cycle becomes longer, the productivity is lowered, and the time that the water-soluble binder comes into contact with CO ₂ in the air becomes longer, which may cause problems such as deactivation. Because it becomes higher. The moisture content of the dry powdered coated sand thus obtained is generally about 5 to 55% by mass, preferably 10 to 50% by mass, based on the solid content of the water-soluble binder. In particular, when the water-soluble binder is water glass, it is formed as a coated sand having a moisture content adjusted to 20 to 50% by mass.

Furthermore, in the manufacturing process of such dry coated sand, as one of effective means for quickly evaporating the water in the water-soluble binder, the refractory aggregate is preheated, A technique is adopted in which a water-soluble binder in the form of an aqueous solution is kneaded or mixed and mixed. By mixing or mixing the water-soluble binder with this preheated refractory aggregate, the water in the water-soluble binder is evaporated very rapidly by the heat of such a refractory aggregate. Therefore, the moisture content of the coated sand obtained can be effectively reduced, and a dry powder having room temperature fluidity can be advantageously obtained. The preheating temperature of such a refractory aggregate is appropriately selected according to the water content of the water-soluble binder, the blending amount thereof, etc., but is generally about 100 to 160 ° C., preferably 100 to It is desirable to heat the refractory aggregate to a temperature of about 140 ° C. If this preheating temperature is too low, it is not possible to effectively evaporate water, and it takes time to dry. Therefore, it is desirable to employ a temperature of 100 ° C. or higher. When the coated sand is too high, the water-soluble binder component hardens when the coated sand obtained is cooled, and in addition, the formation of composite particles proceeds, so there is a problem in the physical properties such as the strength of the coated sand, particularly strength. Will be produced.

In the present invention, the dry coated sand obtained as described above is used and transported to the molding site where the mold is produced. Then, at the molding site, the surfactant and / or Alternatively, an aqueous medium containing a polyhydric alcohol is added to wet, and the obtained wet coated sand is filled into a mold to form a target mold. In this case, the step of adding a surfactant and / or a polyhydric alcohol-containing aqueous medium to the dry coated sand and moistening is performed by simply combining the dry coated sand with a predetermined amount of the aqueous medium. Since it is sufficient to moisten the coated sand by putting it in the mixer and mixing it, it can be performed with extremely simple work, even in molding sites where the working environment is bad, It is as it can easily and readily carried out Te fit. In addition, the addition of a surfactant enhances the compatibility between the water-soluble binder that is the coating layer of the coated sand and moisture, and can advantageously improve the fluidity in the wet coated sand. In addition, the improved fluidity improves the filling property of the coated sand into the mold, and in particular, even in a mold with a complicated shape and a long cavity path from the filling port to the completion of filling. Without filling. In addition, when polyhydric alcohol is added, the strength of the mold can be advantageously improved, and since it has a moisturizing effect, the moisturizing property of the coated sand in the wet state is improved and the pot life is extended. There is an advantage that can be.

Furthermore, such wet coated sand can be moistened by simply adding a surfactant and / or a polyhydric alcohol-containing aqueous medium, and kneading the viscous water-soluble binder into the refractory aggregate. Since the workability is extremely good and the wetted coated sand is difficult to adhere to a mixer, a mold or the like, the device exhibits a feature that makes it difficult to get dirty. In the molding site, since the water-soluble binder, particularly water glass, is not handled, there is an advantage that the worker is not likely to receive chemical injury.

Here, the surfactant and / or polyhydric alcohol-containing aqueous medium used in the present invention is dissolved by adding at least one of the surfactant and the polyhydric alcohol to water in a predetermined ratio. Or it is prepared by dispersing. In addition, various additives pointed out in this specification and other additives known to those skilled in the art are added and contained in the aqueous medium as necessary.

In addition, when such an aqueous medium is added to the dry coated sand, the amount of the surfactant is 0.1 to 20% with respect to 100 parts by mass of the solid content of the water-soluble binder in the coated sand. It is desirable to use an aqueous medium so as to be 0 parts by mass, and it is particularly preferable to use an aqueous medium so as to be 0.5 to 15.0 parts by mass, particularly 0.75 to 12.5 parts by mass. . As the surfactant, any of cationic, anionic, amphoteric, nonionic, silicone type and fluorine type can be used.

Specifically, examples of the cationic surfactant include aliphatic amine salts, aliphatic quaternary ammonium salts, benzalkonium salts, benzethonium chloride, pyridinium salts, imidazolinium salts, and the like. Examples of the anionic surfactant include fatty acid soap, N-acyl-N-methylglycine salt, N-acyl-N-methyl-β-alanine salt, N-acyl glutamate, alkyl ether carboxylate, acyl Peptide, alkyl sulfonate, alkyl benzene sulfonate, alkyl naphthalene sulfonate, dialkyl sulfosuccinate ester, alkyl sulfoacetate, α-olefin sulfonate, N-acylmethyl taurine, sulfated oil, higher alcohol Sulfate, secondary higher alcohol sulfate, alkyl ether sulfate, secondary higher alcohol ethoxy sulfate, polyoxyethylene alkyl phenyl ether sulfate, monoglyculate, fatty acid alkylolamide sulfate, alkyl ether phosphorus Acid Examples include stealth salts and alkyl phosphate ester salts. Furthermore, examples of the amphoteric surfactant include carboxybetaine type, sulfobetaine type, aminocarboxylate, imidazolinium betaine and the like. In addition, nonionic surfactants include polyoxyethylene alkyl ether, polyoxyethylene secondary alcohol ether, polyoxyethylene alkylphenyl ether (eg, Emulgen 911), polyoxyethylene sterol ether, polyoxyethylene lanolin derivative Polyoxyethylene polyoxypropylene alkyl ether (for example, New Pole PE-62), polyoxyethylene glycerin fatty acid ester, polyoxyethylene castor oil, hydrogenated castor oil, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, Polyethylene glycol fatty acid ester, fatty acid monoglyceride, polyglycerin fatty acid ester, sorbitan fatty acid ester, propylene glycol fat Esters, sucrose fatty acid esters, fatty acid alkanolamides, polyoxyethylene fatty acid amides, polyoxyethylene alkyl amines, alkyl amine oxides, acetylene glycol, acetylene alcohol, and the like. Among various surfactants, those having a siloxane structure as a nonpolar site are particularly referred to as silicone surfactants, and those having a perfluoroalkyl group are referred to as fluorine surfactants. Examples of the silicone-based surfactant include polyester-modified silicone, acrylic-terminated polyester-modified silicone, polyether-modified silicone, acrylic-terminated polyether-modified silicone, polyglycerin-modified silicone, and aminopropyl-modified silicone. In addition, as fluorosurfactants, perfluoroalkyl sulfonates, perfluoroalkyl carboxylates, perfluoroalkyl phosphates, perfluoroalkyltrimethylammonium salts, perfluoroalkylethylene oxide adducts, perfluoroalkyl groups Containing oligomers and the like. And these surfactants are used individually or in mixture of 2 or more types.

In addition, the polyhydric alcohol used instead of or together with the above surfactant is generally 0.1 to 20.0 mass per 100 mass parts of the solid content of the water-soluble binder in the dry coated sand. An aqueous medium containing such a polyhydric alcohol is preferably used in an amount of 0.5 to 15.0 parts by mass, more preferably 0.75 to 12.5 parts by mass. It will be added to the coated sand. Specific examples of the polyhydric alcohol used here include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, dipropylene glycol, propylene glycol, butylene glycol, 1,2-butanediol, and 1,2-pentane. Diol, 1,5-pentanediol, 1,2-hexanediol, 2-ethyl-1,3-hexanediol, 1,6-hexanediol, 1,2-heptanediol, 1,2-octanediol, 1, Examples include 2,6-hexanetriol, thioglycol, hexylene glycol, glycerin, trimethylolethane, and trimethylolpropane. And these can be used individually or in mixture of 2 or more types.

The aqueous medium containing the surfactant and / or polyhydric alcohol prepared as described above can also contain various known additives as necessary. For example, an acid or an ester may be contained as the curing agent, and among them, sulfuric acid, hydrochloric acid, carbonic acid, and sulfonic acids are preferable as the acid. Examples of the ester include lactones such as γ-butyrolactone and ε-caprolactone, Esters derived from an alcohol having 1 to 10 carbon atoms and a carboxylic acid having 1 to 10 carbon atoms such as ethylene glycol diacetate, triacetin, diethylene glycol diacetate and triethylene glycol diacetate are preferred. In this case, the alcohol having 1 to 10 carbon atoms may be monovalent or polyvalent. Moreover, you may contain a metal salt, a metal powder, etc. as a hardening accelerator. Therefore, the metal salt is preferably a metal salt such as calcium, magnesium, aluminum, or iron, and the metal powder is preferably a metal powder such as calcium, magnesium, zinc, aluminum, or silicon. Furthermore, drying accelerators such as alcohols such as methanol, which are organic solvents, and ketones such as acetone and diacetone alcohol, PROXEL GXL [1,2-benzoisothiazol-3 (2H) -one manufactured by Lonza Japan Co., Ltd. ] Or PROXEL IB (polyhexamethylene biguanidine) and a silane coupling agent may be added in a small amount.

Moreover, a second water-soluble binder can be added as a further additive for adjusting the mold strength. The second water-soluble binder is appropriately selected from the water-soluble binders exemplified above, and may be the same as or different from the water-soluble binder covering the coated sand. However, there is no problem. By adding such a second water-soluble binder at the time of mold making, depending on the shape and size of the mold to be produced, in order to increase the strength of the mold, the second water-soluble binder may be further added. Thus, the strength can be improved. In addition, since the addition amount of the second water-soluble binder is for adjustment, the solid content of the second water-soluble binder to be added is reduced with respect to the solid content of the water-soluble binder in the coated sand. Is desirable.

Furthermore, in accordance with the present invention, spherical particles are added as a further additive when adding an aqueous medium containing a surfactant and / or a polyhydric alcohol to the dry coated sand and moistening. It is also effective. By adding such spherical particles, it is possible to advantageously contribute to improvement of the filling property of the coated sand at the time of mold making. Such spherical particles may be added in a state of being mixed with a surfactant and / or a polyhydric alcohol-containing aqueous medium, or added separately from the surfactant and / or the polyhydric alcohol-containing aqueous medium. It is also possible to do. The addition amount of the spherical particles is about 0.1 to 20.0 parts by mass, preferably 0.5 to 15.0 parts by mass with respect to 100 parts by mass of the solid content of the water-soluble binder in the coated sand. More preferably, the content is 0.75 to 12.5 parts by mass.

As such spherical particles, those having a sphericity of 0.5 or more are usually desirable. Among them, particles having a sphericity of preferably 0.7 or more, more preferably 0.9 or more are advantageously used. It will be. Here, the sphericity is the average value of the aspect ratio (minor axis / major axis ratio) obtained from the projection shape of 10 single particles randomly selected in scanning electron microscope observation. I mean. The average particle diameter of such spherical particles is about 0.1 to 25.0 μm, preferably about 1.0 to 20.0 μm. The material of the spherical particles is not particularly limited, Advantageously, spherical particles such as amorphous silica, alumina, titanium oxide and the like are preferably used.

By the way, when the above-mentioned dry coated sand is moistened, a predetermined amount of a surfactant and / or a polyhydric alcohol-containing aqueous medium is added to the dry coated sand at the mold making site. By mixing with an ordinary mixer, the desired wetted coated sand is formed, but the amount of water supplied by the surfactant and / or polyhydric alcohol-containing aqueous medium used therein is The amount of the water glass component constituting the coated sand is appropriately determined according to the type and amount of use, and generally, in order to wet the dry coated sand, 0.5 to 5 parts by mass, preferably 0.75 to 4 parts by mass, more preferably 1 to 3 parts by mass. In, will be determined as appropriate. The amount of the surfactant and / or polyhydric alcohol-containing aqueous medium is determined by the amount of water, surfactant, or polyhydric alcohol to be added, but generally 100 parts by mass of the coated sand. The ratio is appropriately determined in the ratio of 0.5 to 6 parts by mass, preferably in the ratio of 0.75 to 4 parts by mass, more preferably in the ratio of 1 to 3.5 parts by mass. . If the amount of the surfactant and / or the polyhydric alcohol-containing aqueous medium is too small, it is not possible to sufficiently wet the coated sand in the dry state. As a result of the weak adhesion, the fluidity of the coated sand deteriorates and the filling property into the mold deteriorates. As a result, the strength of the resulting mold is reduced. On the other hand, if the amount of the surfactant and / or the polyhydric alcohol-containing aqueous medium is excessively increased, the filling operation into the mold becomes difficult, and the drying operation after filling into the mold is time-consuming. In short, it causes problems such as a long molding time.

In the present invention, the dried coated sand wet product obtained as described above is used to fill a predetermined mold, specifically, the mold cavity of the mold. Then, by drying the wetted coated sand, a mold having a target shape is formed. At this time, the wetted coated sand used is directly coated with a water-soluble binder. It has better fluidity than wet coated sand obtained by kneading into refractory aggregates, and it has improved adhesiveness due to reduced adhesion and adhesion between sand. In addition, since the adhesion to the mold can be effectively reduced, the dirt on the mold can be advantageously suppressed, and the mold releasability from the mold can be advantageously improved. is there. Incidentally, for filling such a wet coated sand into the mold, a blow filling method using a blow head is preferably employed, and the blow pressure at that time is about 0.2 to 0.6 MPa, The pressure is preferably about 0.3 to 0.5 MPa.

In addition, in this way, when the target mold is molded by drying the wetted coated sand filled in the mold and solidifying or curing it, the wetted sand is dried. In order to be advantageous, it is desirable to heat the mold, which is recommended in the present invention. By using this heated mold, the drying of the filled wetted sand can be effectively advanced so that the molding time can be advantageously shortened. As the heating temperature of such a mold, generally a temperature within the range of 40 to 250 ° C., preferably 70 to 200 ° C., more preferably 100 to 175 ° C. is employed. If this heating temperature is less than 40 ° C., it is difficult to sufficiently exert the drying accelerating effect due to heating, and there is a problem that the molding time becomes long. The coated sand is solidified or hardened too quickly, and its filling property is deteriorated. Also, the wet coated sand is too dried, the tackiness is lost, and the adhesive effect is lowered. Problems such as a decrease in strength also arise.

And, in order to promote drying of the wetted coated sand filled in the mold, it is also effective to directly heat the filled wetted coated sand in the microwave, In particular, when the mold is a resin mold, it is preferably employed. Further, by allowing heated air or dry air to pass through a mold filled with wetted coated sand and passing through a packed bed of wetted coated sand, drying is promoted and the filling is performed more quickly. It is also effective to solidify or harden the wet coated sand. In addition, it is one of the effective drying means to vacuum-dry the inside of the mold by sucking the mold filled with wet coated sand under reduced pressure. In a mold of a material that is easily received, it is advantageously employed.

Furthermore, in the present invention, as described above, the moisture of the surfactant and / or polyhydric alcohol-containing aqueous medium used for the moistening is used from the moistened coated sand filled in the mold. By removing it, the target mold will be formed, but at that time, the water glass constituting the coating layer on the surface of the coated sand is usually not added with any additives, If it is solidified by evaporating to dryness of water and an oxide or salt is added as a curing agent, it will be cured. In order to cure such water glass, it is also effective to ventilate carbon dioxide gas or organic ester gas into a mold filled with wetted coated sand. It is possible to cure the water glass quickly and advantageously increase the molding speed. As the organic ester gas, for example, methyl formate, ethyl formate, propyl formate, γ-butyrolactone, γ-propionlactone, ethylene glycol diacetate, diethylene glycol diacetate, glycerin diacetate, triacetin, propylene carbonate and the like are gaseous or Atomized and used.

According to the present invention, as a method of moistening the dry coated sand and molding it with a predetermined mold, it is possible to produce a mold by employing various known molding methods. Furthermore, the present invention can be carried out in a mode to which various changes, modifications, improvements, etc. are added based on the knowledge of those skilled in the art, and such a mode of implementation does not depart from the gist of the present invention. Insofar, it should be understood that all belong to the scope of the present invention.

Hereinafter, the present invention will be more specifically clarified by using some examples, but the present invention is not construed as being limited in any way by the description of such examples. Should be understood. In the following examples and comparative examples, “%” and “parts” are shown on a mass basis unless otherwise specified. Moreover, the water content, filling property, filling fluidity, and strength of the coated sand (CS) obtained in Examples and Comparative Examples were evaluated as follows.

-Measurement of water content relative to solid content of water-soluble binder-
The method is not particularly limited as long as it can measure the moisture content in CS, and an effective measurement method can be selected depending on the type of binder. An example of the measurement method is shown below.

(When water-soluble binder is water glass)
Each CS is weighed and accommodated in a crucible that has been baked and weighed, and the amount of moisture (W1) in the CS is calculated using the mass loss (%) after heating at 900 ° C. for 1 hour. It calculates from the following formula (1). The weighing is measured to the fourth decimal place. Next, the binder solid content (B1) with respect to CS is calculated using the following formula (2), and then the water content (W2) with respect to the solid content of the binder is calculated from the following formula (3). ) To calculate.
W1 = [(M1-M2) / M3] × 100 (1)
[W1: Moisture content (%) in CS, M1: Total mass (g) of crucible and CS before firing, M2: Total mass (g) of crucible and CS after firing, M3: CS before firing Mass (g)]
B1 = [B2 / (100 + B2)] × (100−W1) (2)
[B1: solid content (%) of binder with respect to CS, B2: solid content (parts) of binder added to 100 parts of sand, W1: moisture content (%) in CS]
W2 = (W1 / B1) × 100 (3)
[W2: Water content (%) with respect to binder solid content, W1: Water content (%) in CS, B1: Binder solid content (%) with respect to CS]

(When water-soluble binder is water-soluble resol resin)
Weigh 2.0 g of each CS and add 100 ml of Aquamicron ML (Mitsubishi Chemical Corporation), a dehydrating solvent, to a flask of a Karl Fischer moisture meter (Hiranuma Sangyo Co., Ltd .: AQV-7 HIRANUMA AQUACOUNTER) [in advance The Karl Fischer reagent (Sigma-Aldrich Laborchemikalien Gmbh: Hydranal Composite 5) was added dropwise and the water content was kept at 0], and stirred for several minutes using a magnetic stirrer. Hydranal composite 5 was dropped and the moisture content (W1) in CS was quantified. Thereafter, the moisture content (W2) relative to the solid content of the binder was calculated from the moisture content (W1) in CS using the above formulas (2) and (3).

-Measurement of fillability and evaluation of filling fluidity-
The CS of each example or each comparative example is divided into one mold half 5 having a parting surface as shown in FIG. 1 and the other mold half having a parting surface symmetrical to the mold half (5 ), And the molding die is filled at a blow pressure of 0.3 MPa from the filling port 6 and molded at a molding die temperature of 150 ° C. and a molding time of 180 seconds. (G) is measured. Next, in the molded mold, the CS filling state with respect to the flow paths 1 to 4 in the cavity is visually evaluated. The filled state of each flow path is determined as ◯: filled, Δ: filled but slightly deficient, x: not filled, and the flow path portion is deficient. The channels 2 to 4 are filled, and the channel 1 that is filled with Δ or more is regarded as acceptable.

-Measurement of bending strength-
About the test piece of width | variety: 1.0cmxheight: 1.0cmxlength: 6.0cm obtained using each CS, the breaking load was measured with the measuring device (Takachiho Seiki Co., Ltd. product: Measure using a digital foundry sand strength tester). And the bending strength is calculated by the following formula (4) using the measured breaking load.
Bending strength (N / cm ² ) = 1.5 × LW / ab ² (4)
[L: distance between fulcrums (cm), W: breaking load (N), a: width of test piece (c
m), b: thickness of test piece (cm)]

-Production example 1 of dry CS
As refractory aggregate, Lunamos # 80 (trade name: manufactured by Kao Quaker Co., Ltd.), which is a commercially available artificial sand for casting, is prepared, and as a water glass used as a binder (water-soluble binder), a commercial product: No. 2 sodium silicate (trade name: manufactured by Fuji Chemical Co., Ltd., SiO ₂ / Na ₂ O molar ratio: 2.5, solid component: 41.3%) was prepared. The lunamos # 80 is heated to a temperature of about 120 ° C., and is then introduced into a Shinagawa universal agitator (5DM-r type) (Dalton Co., Ltd.). 1.21 parts (solid component: 0.50 part) with respect to the part, knead for 3 minutes to evaporate the water, and while stirring and mixing until the sand granule collapses, it is taken out As a result, dry coated sand: CS1 having free fluidity at room temperature was obtained. When the moisture content of CS1 after such kneading was measured, it was 0.2% (/ CS).

-Production example 2- of dry CS
Commercially available product: No. 1 sodium silicate (trade name: manufactured by Fuji Chemical Co., Ltd., molar ratio of SiO ₂ / Na ₂ O: 2.1, solid component: 48.5%) is used as the water glass for the binder. In addition, according to the same procedure as in Production Example 1 except that the amount of water glass added was 1.03 parts (0.50 parts of solid component) with respect to 100 parts of Lunamos # 80. , Dry CS2 was obtained. And when the moisture content of CS2 after the kneading was measured, it was 0.2% (/ CS).

-Production example of dry CS 3-
As a water glass of a binder, a commercially available product: No. 3 sodium silicate (trade name: manufactured by Fuji Chemical Co., Ltd., SiO ₂ / Na ₂ O molar ratio: 3.2, solid component: 38%) was prepared, According to the procedure similar to the said manufacture example 1, except that the addition amount of this water glass was made into the ratio of 1.32 parts (solid component 0.50 part) with respect to 100 parts of Lunamos # 80, it is a dry state. CS3 was obtained. And when the moisture content of CS3 after the kneading was measured, it was 0.2% (/ CS).

-Production example 4 of dry CS
A commercially available product: HPR833 (trade name: manufactured by Asahi Organic Materials Co., Ltd., nonvolatile component: 45%) was prepared as a water-soluble resol which is a binder (water-soluble binder). The lunamos # 80 is heated to a temperature of about 120 ° C. and then charged into a Shinagawa universal stirrer (5DM-r type) (Dalton Co., Ltd.). The mixture was added at a ratio of 1.33 parts (resin component 0.6) with respect to the parts, and kneading was performed for 60 seconds to evaporate the moisture, while stirring and mixing until the sand granule collapsed. Then, by taking out from the stirrer, dry CS4 having free flowability at room temperature was obtained. Moreover, when the moisture content of CS4 after the kneading | mixing obtained was measured, it was 0.2% (/ CS).

-Manufacture example 1 of wet CS
Lunamos # 80 (trade name: manufactured by Kao Quaker Co., Ltd.), a commercially available artificial sand for casting, is prepared as a fire-resistant aggregate, and a commercial product: No. 2 sodium silicate (product) Name: manufactured by Fuji Chemical Co., Ltd.). Next, the above-mentioned lunamos # 80 at room temperature was put into a Shinagawa universal agitator (5DM-r type) (manufactured by Dalton Co., Ltd.), and the water glass was further added to 1.100 parts of lunamos # 80. While adding 21 parts (solid component 0.50 part), 0.46 part of water was added and kneading for 3 minutes was performed to obtain wet CS5. When the moisture content of CS5 after such kneading was measured, it was 1.15% (/ CS), and when the dynamic angle of repose was measured, it became wet and has no room temperature fluidity. The dynamic angle of repose could not be measured.

-Examples of mold making-
(Example 1)
Using an commercially available product: Olfine PD-301 (trade name: manufactured by Nissin Chemical Industry Co., Ltd.) as an anionic surfactant, adding 0.02 part thereof to 2 parts of water, mixing and stirring Thus, a surfactant-containing aqueous solution as an aqueous medium was obtained. Then, 100 parts of CS1 obtained in the above dry production example 1 was put into a Shinagawa universal stirrer (5DM-r type), and a surfactant-containing aqueous solution as an aqueous medium was further added. (Thus, the surfactant is in a ratio of 4.0 parts with respect to 100 parts of the solid content of water glass in CS1) and stirred for 1 minute. The wet CS thus obtained is placed in a blow tank and blown into a mold consisting of a pair of mold halves 5 heated to 150 ° C. at a gauge pressure of 0.3 MPa and filled. It was. And after hold | maintaining for 180 second, the casting_mold | template as a test piece was obtained by removing from a shaping | molding die.

(Example 2)
By adding 0.05 part of an anionic surfactant (10 parts to 100 parts solid content of water glass which is a water-soluble binder) to 2 parts of water, and mixing and stirring. A mold (test piece) was prepared according to the same procedure as in Example 1 except that the aqueous medium was used.

(Example 3)
An aqueous surfactant was prepared by adding 0.06 part of an anionic surfactant (12 parts with respect to 100 parts of the solid content of water glass) to 2 parts of water and mixing and stirring. Except for this, a template (test piece) was prepared according to the same procedure as in Example 1.

Example 4
A mold (test piece) was prepared according to the same procedure as in Example 2 except that dry CS1 was changed to dry CS2.

(Example 5)
A mold (test piece) was prepared according to the same procedure as in Example 2 except that dry CS1 was changed to dry CS3.

(Example 6)
A commercially available product: KF643 (trade name: manufactured by Shin-Etsu Chemical Co., Ltd.) is prepared as a silicone-based surfactant, and 0.005 part thereof (the ratio is 1 part with respect to 100 parts of the solid content of water glass). A mold (test piece) was prepared according to the same procedure as in Example 1 except that it was added to 2 parts of water, mixed and stirred to obtain an aqueous medium.

(Example 7)
A commercially available product: KF640 (trade name: manufactured by Shin-Etsu Chemical Co., Ltd.) is prepared as a silicone-based surfactant, and 0.005 part thereof (the ratio is 1 part with respect to 100 parts of the solid content of water glass). A mold (test piece) was prepared according to the same procedure as in Example 1 except that it was added to 2 parts of water, mixed and stirred to obtain an aqueous medium.

(Example 8)
A template (test piece) was prepared in the same manner as in Example 2 except that a commercially available product: Liporan LB-440 (trade name: manufactured by Lion Corporation) was used as the anionic surfactant.

Example 9
A mold (test piece) was prepared according to the same procedure as in Example 2 except that a commercially available product: Surfynol 465 (trade name: manufactured by Nissin Chemical Industry Co., Ltd.) was used as the nonionic surfactant.

(Example 10)
A mold (test piece) was prepared in the same manner as in Example 2 except that a commercially available product: Surfynol 485 (trade name: manufactured by Nissin Chemical Industry Co., Ltd.) was used as the nonionic surfactant.

(Example 11)
As an anionic surfactant, a commercially available product: Olphine PD-301 (trade name: manufactured by Nissin Chemical Industry Co., Ltd.) was used, and 0.02 part thereof (a ratio of 4 parts to 100 parts of the solid content of water glass) And 0.04 part of glycerin as polyhydric alcohol (the ratio is 8 parts with respect to 100 parts of the solid content of water glass) is added to 2 parts of water and mixed and stirred. Thus, a template (test piece) was prepared according to the same procedure as in Example 1 except that the aqueous medium was used.

(Example 12)
As an anionic surfactant, a commercially available product: Olphine PD-301 (trade name: manufactured by Nissin Chemical Industry Co., Ltd.) was used, and 0.05 parts thereof (a ratio of 10 parts to 100 parts of solid content of water glass) And 0.04 part of glycerin as polyhydric alcohol (the ratio is 8 parts with respect to 100 parts of the solid content of water glass) is added to 2 parts of water and mixed and stirred. Thus, a template (test piece) was prepared according to the same procedure as in Example 1 except that the aqueous medium was used.

(Example 13)
As a surfactant, commercially available product: Olfine PD-301 (trade name: manufactured by Nissin Chemical Industry Co., Ltd.), 0.05 part thereof (10 parts per 100 parts of water glass solid content) Was added to 2 parts of water, and the aqueous medium obtained by mixing and stirring was mixed with 0.05 parts of spherical particles of HS311 (trade name: manufactured by Nippon Steel & Sumikin Materials Co., Ltd.) A mold (test piece) was prepared according to the same procedure as in Example 1 except that 10 parts of solid content was added and used. The aspect ratio of HS311 was measured and found to be 0.91.

(Example 14)
A mold (test piece) was prepared according to the same procedure as in Example 2 except that dry CS1 was changed to dry CS4.

(Example 15)
By using glycerin as a polyhydric alcohol, adding 0.04 part thereof (a ratio of 8 parts to 100 parts of solid content of water glass) to 2 parts of water, and mixing and stirring, A template (test piece) was prepared according to the same procedure as in Example 1 except that the aqueous medium was used.

(Example 16)
As a polyhydric alcohol, a polyethylene glycol commercial product: PEG400 (product name: Daiichi Kogyo Seiyaku Co., Ltd.) is used, and 0.04 part thereof (a ratio of 8 parts to 100 parts of the solid content of water glass) is 2 A mold (test piece) was prepared according to the same procedure as in Example 1 except that it was added to a portion of water and mixed and stirred to obtain an aqueous medium.

(Example 17)
Obtained by using glycerin as the polyhydric alcohol, adding 0.04 part thereof (a ratio of 8 parts to 100 parts of solid content of water glass) to 2 parts of water, and mixing and stirring. To the resulting aqueous medium, add 0.05 part of HS311 (trade name: manufactured by Nippon Steel & Sumikin Materials Co., Ltd.) as spherical particles (the ratio is 10 parts with respect to 100 parts of the solid content of water glass). A mold (test piece) was prepared according to the same procedure as in Example 1 except that it was used.

(Example 18)
A mold (test piece) was prepared according to the same procedure as in Example 15 except that dry CS1 was changed to dry CS4.

(Comparative Example 1)
A template (test piece) was prepared according to the same procedure as in Example 1 except that normal tap water to which no surfactant or polyhydric alcohol was added was used as the aqueous medium.

(Comparative Example 2)
Wet CS5 was placed in a blow tank and blown into a mold heated to 150 ° C. at a gauge pressure of 0.3 MPa to be filled. And after hold | maintaining in a type | mold for 180 second, the casting_mold | template (test piece) was obtained by taking out from a shaping | molding die.

(Comparative Example 3)
A template (test piece) was prepared according to the same procedure as in Example 14 except that normal tap water to which no surfactant or polyhydric alcohol was added was used as the aqueous medium.

For each of the molds (test pieces) obtained in Examples 1 to 18 and Comparative Examples 1 to 3, the filling property and filling fluidity are evaluated according to the test method described above, and the strength is measured. The results are shown in Tables 1 to 3 below.

As is clear from the results of Tables 1 to 3, in Examples 1 to 18, the template obtained from CS wetted with the surfactant and / or polyhydric alcohol-containing aqueous medium according to the present invention was used. It can be seen that both show good filling and filling fluidity of the coated sand.

On the other hand, according to Comparative Examples 1 to 3, the dry CS is moistened using only water, or the wet CS is directly formed using water glass. In the molded mold, it is recognized that the filling ability and filling fluidity of CS into the mold are not sufficient.

In addition, it can be seen that the molds obtained in Examples 1 to 18 have an effective improvement in strength over the comparative example using CS wetted by kneading only water.

1-4 Flow path 5 Mold half 6 Filling port

Claims

An aqueous medium containing a surfactant and / or a polyhydric alcohol was added to a dry coated sand obtained by coating the surface of a refractory aggregate with a water-soluble binder, and was wetted. Then, a mold manufacturing method is characterized in that the obtained wet coated sand is filled into a mold and then molded.
The method for producing a mold according to claim 1, wherein the aqueous medium is added to the coated sand at a ratio of 0.5 to 6 parts by mass with respect to 100 parts by mass of the coated sand. .
The aqueous medium is added so that the surfactant has a ratio of 0.1 to 20.0 parts by mass with respect to 100 parts by mass of the solid content of the water-soluble binder in the coated sand. The manufacturing method of the casting_mold | template of Claim 1 or Claim 2.
The aqueous medium is added such that the polyhydric alcohol is in a ratio of 0.1 to 20.0 parts by mass with respect to 100 parts by mass of the solid content of the water-soluble binder in the coated sand. The method for producing a mold according to any one of claims 1 to 3.
The method for producing a mold according to any one of claims 1 to 4, wherein spherical particles are further added when the dry coated sand is wetted.
The mold according to claim 5, wherein the amount of the spherical particles added is 0.1 to 20.0 parts by mass with respect to 100 parts by mass of the solid content of the water-soluble binder in the coated sand. Production method.
The method for producing a mold according to any one of claims 1 to 6, wherein a second water-soluble binder is further added to wet the dry coated sand.
The method for producing a mold according to any one of claims 1 to 7, wherein the moisture content in the dry coated sand is 5 to 55 mass% of the solid content of the water-soluble binder. .
9. The water-soluble binder according to claim 1, wherein one or more of thermosetting resins, saccharides, proteins, synthetic polymers, salts and inorganic polymers are selected and used. The manufacturing method of the casting_mold | template of any one.
The method for producing a mold according to claim 9, wherein the inorganic polymer is water glass.
The method for producing a mold according to any one of claims 1 to 10, wherein heated air or dry air is passed through a mold filled with the wetted coated sand.
The method for producing a mold according to any one of claims 1 to 11, wherein carbon dioxide gas or organic ester gas is aerated in a mold filled with the wetted coated sand.
The method for producing a mold according to any one of claims 1 to 12, wherein the mold is heated to a temperature of 40 ° C to 250 ° C.