JPWO2018043412A1 - Method of manufacturing mold - Google Patents

Abstract

Provided is a method of manufacturing a mold which can effectively improve the workability at the molding site while improving the filling property of the coated sand and the strength of the mold. In addition, the present invention provides a method capable of advantageously manufacturing a target mold by using a conventional molding apparatus as it is without the need to newly install a special apparatus. The dry coated sand obtained by coating the surface of the fireproof aggregate with a water-soluble binder was moistened by adding an aqueous medium comprising a surfactant and / or a polyhydric alcohol. Thereafter, the obtained wetted coated sand is filled into a mold to form a target mold.

Description

  The present invention relates to a method for producing a mold, and in particular, it is possible to advantageously produce a mold while improving the filling property of the coated sand and the strength of the mold while improving the workability at the molding site which is the production site of the mold. It is about the way it can be done.

  Conventionally, as one of the manufacturing methods of molds used for casting molten metal, a coated sand obtained by coating mold sand made of refractory aggregate with a predetermined binder is used to obtain a target shape A method of molding a mold is adopted, and as a binder used therein, for example, in "Casting Engineering Handbook" edited by Japan Casting Engineering Association, pages 78 to 90, inorganic systems such as water glass are used. In addition to the caking agent, organic caking agents using resins such as phenol resin, furan resin, urethane resin and the like have been clarified, and in these cases, the self-hardening mold is formed using these caking agents. The method is also clarified.

  And after forming coated sand which is made to coat predetermined fireproof aggregate (mold sand) using water glass which is one of the inorganic type binders among these cinders, molding of a mold is carried out. Various methods have been proposed as a method of performing the reaction, for example, in Japanese Patent Application Laid-Open No. 2008-036712, silica sand (refractory aggregate), alkali silicate (water glass), and amorphous dioxide are used. A mold material or mold part containing silicon-containing agglomerates is disclosed. Also, there, at the molding site of the mold, the silica sand, the water glass and the amorphous silicon dioxide are kneaded, and a wet alkali silicate (water glass) is attached to the surface of the silica sand. The mold material (coated sand) is in a wet form (moist state), and it is filled into a predetermined mold so that a mold having a desired shape is formed.

  However, such a wet coated sand reacts with carbon dioxide in the air, and from the place where curing gradually proceeds, the pot life is short and the storage stability is not sufficient, and therefore Generally, such wet coated sand is produced at the molding site of the mold, and then filled into the mold as it is, whereby the target mold is formed. Thus, the powdery refractory aggregate and the water glass are transported to a molding site with many obstacles, and they are mixed with a mixer to obtain a wet coated sand, the viscosity of the water glass is high. In addition to the fact that mixing with the fireproof aggregate is difficult due to the fact that it takes considerable labor and time, and the viscosity of the water glass makes it difficult to mix with mixers and molding dies for molding, etc. There is an inherent problem of poor workability in molding, such as easy contamination of the device. In addition, because of the work at the molding site, there is also an inherent problem that the worker is highly likely to be injured by the strongly alkaline water glass.

  On the other hand, unlike the wet coated sand as described above, water glass is used as a caking agent to form a dried coated layer of such a caking agent on the surface of the refractory aggregate, The dry-type coated sand which has normal temperature fluidity is clarified by Unexamined-Japanese-Patent No. 2012-076115. There, such dry coated sand is coated with a solid coating layer containing a water-soluble inorganic compound such as water glass as a caking agent, which is a molding of a mold for mold making After being filled in the cavity, the coated sand is solidified by ventilating water vapor, and a method for obtaining the target mold has been clarified, but in such a molding method It is necessary to blow water vapor into the mold after filling the dry coated sand, and for this reason it is necessary to use the conventional equipment as it is because it is necessary to specially provide a water vapor blowing device. It is not possible to do so, which raises the problem of increasing the cost of manufacturing the mold.

  In addition, since the dry coated sand filled in the mold is wetted with water vapor and then solidified by drying, the mold is formed by such wet coating. In order to effectively dry the sand, it is also necessary to add a new step of blowing a heated gas in addition to the blowing of water vapor, which causes molding from filling to a mold to drying and solidification to hardening. There is also an inherent problem that the cycle becomes long and the productivity of the mold decreases.

JP, 2008-036712, A JP 2012-076115 A

Handbook of Casting Engineering, pp. 78-90

  Here, the present invention has been made against the background described above, and the problem to be solved by the present invention 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 another object of the present invention to provide a method of manufacturing a mold which can effectively achieve the present invention, and another place is that it is basically not necessary to newly install a special device, and basically the device for conventional molding is left as it is. An object of the present invention is to provide a method which can be used to advantageously manufacture a target mold.

  And, in order to solve the problems described above, the present invention can be suitably implemented in various aspects as listed below, and each aspect described below is adopted in any combination. It is possible. It should be noted that aspects or technical features of the present invention can be recognized based on the inventive concept that can be grasped from the description of the entire specification without being limited to the following description. It should be understood.

(1) An aqueous medium comprising a surfactant and / or a polyhydric alcohol is added to the dry coated sand obtained by coating the surface of the refractory aggregate with a water-soluble binder, After moistening, the obtained moistened coated sand is filled in a mold to form a mold.
(2) The aqueous medium is based on 100 parts by mass of the coated sand,
The method for producing a mold according to the above aspect (1), which is added to the coated sand in a proportion of 0.5 to 6 parts by mass.
(3) The aqueous medium is added such 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. Said aspect characterized by
1) or the manufacturing method of the mold as described in said aspect (2).
(4) The aqueous medium is added such that the ratio of the polyhydric alcohol 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. A method for producing a mold according to any one of the above aspects (1) to (3), characterized in that
(5) Aspects (1) to (4), wherein spherical particles are further added when the dry coated sand is moistened.
The manufacturing method of the mold as described in any one of these.
(6) The above aspect (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. The manufacturing method of the mold as described in 2.).
(7) In the above-mentioned embodiment (1), a second water-soluble binder is further added when the dry coated sand is moistened.
A method of producing a mold according to any one of the preceding aspects (6).
(8) The above aspect (11), wherein the water 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 mold as described in any one of said aspect (7).
(9) The above embodiment characterized in that one or two or more selected from thermosetting resins, saccharides, proteins, synthetic polymers, salts and inorganic polymers are used as the water-soluble binder. The method for producing a mold according to any one of the above-mentioned aspects (8).
(10) The above-mentioned embodiment (wherein the inorganic polymer is water glass)
The manufacturing method of the mold as described in 9).
(11) In any one of the modes (1) to (10), heated air or dry air is ventilated in the mold filled with the wet coated sand. Method for producing a mold according to the description.
(12) In any one of the above aspects (1) to (11), a carbon dioxide gas or an organic ester gas is allowed to pass through the mold filled with the wetted coated sand. Method for producing a mold according to the description.
(13) The method for producing a mold according to any one of the aspects (1) to (12), wherein the mold is heated to a temperature of 40 ° C. to 250 ° C.

  Thus, in the present invention, first, a dry coated sand is prepared in advance using a water-soluble binder such as water glass as a binder, and then it is brought to a molding site, At the molding site, only by preparing a surfactant and / or a polyhydric alcohol-containing aqueous medium for moistening the dry coated sand, it is possible to form a target mold. There is no need to knead the viscous water glass to the fireproof aggregate at the molding site where the working environment is bad, and the workability at the molding site can be remarkably improved. In addition, even if it is wetted by adding a surfactant and / or a polyhydric alcohol-containing aqueous medium to dry coated sand in a mixer, the mixture adheres to the mixer even if it is moistened. In addition to the fact that the equipment is not easily soiled, in addition to the fact that a water-soluble binder such as water glass is not handled at the molding site, workers are injured by such water glass and other water-soluble binders. There is no fear of being

  Furthermore, the addition of a surfactant and / or a polyhydric alcohol to the aqueous medium used to wet the coated sand advantageously improves the packing properties of the coated sand during mold making. As a result, it has become possible to bring about advantageously the characteristic that it is possible to effectively improve the strength of the resulting template.

  Further, in the present invention, the dry coated sand prepared in advance is hardly changed with time by carbon dioxide gas in the air unless an aqueous medium is added, and the dry state coated sand has a good storage stability. A large amount of coated sand is prepared beforehand in a place different from the molding site, and a part of the molding site is used to add a surfactant and / or a polyhydric alcohol-containing aqueous medium to the molding site, It has the practical advantage of being able to mold the target mold after it has been moistened, as well as such dry coated sand moistened at the molding site as in the past. The present invention exhibits the special feature that the filling property to the mold is better than the wet coated sand to be produced, and furthermore, the releasability of the molded mold from the mold is also improved.

  Furthermore, according to the method for producing a mold according to the present invention, the surface containing the surfactant and / or the polyhydric alcohol is only required to be filled with moistened coated sand in a mold at a molding site and then heated etc. Since it is something that evaporates the moisture of the medium and dries and solidifies or hardens, it is necessary to newly install a special device such as a water vapor generator or a water vapor venting mechanism as in the case of using dry coated sand as it is. Basically, it is possible to carry out molding using the conventional device as it is, and thereby it is possible to avoid an increase in the device cost and hence an increase in the manufacturing cost of the mold. There is no need to newly adopt a steam injection step, whereby it can be advantageously avoided that the molding cycle is lengthened. It became of the is.

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

  By the way, in the method for producing a mold according to the present invention, the dry coated sand prepared in advance generally mixes the refractory aggregate with a water soluble binder in the form of an aqueous solution as a binder. The dried coating layer which is produced by evaporating the water from the mixture, in other words by evaporating the water of the water-soluble binder in the form of an aqueous solution, and which comprises a solid of the water-soluble binder which is a binder is It is a dry state which is formed on the surface of the refractory aggregate at a predetermined thickness, and has good cold flowability. In particular, in the present invention, the water content in such dry coated sand is preferably 5 to 55% by mass with respect to the solid content of the water-soluble binder, and preferably 10 to 50. It is desirable that it is mass%. In particular, in the case where the water-soluble binder is water glass, 20 to 50% by mass is desirable. When the water content is less than 5% by mass, there is a problem that the water-soluble binder such as water glass is vitrified and the solution does not return even if water is added again, while 55% by mass If it is more than that, there is a problem that it does not become dry.

  Here, in the dry coated sand used in the present invention, the range of the amount of water giving the dry state varies depending on the nature of the water-soluble binder. For this reason, the dry state in the present invention means one that can obtain a measured value of the dynamic angle of repose when the dynamic angle of repose is measured regardless of the amount of water. The dynamic repose angle means that coated sand is contained in a cylinder in which one end in the axial direction is closed by a transparent plate material (for example, a container having a diameter of 7.2 cm and a height of 10 cm). Hold coated sand in a horizontal direction (up to half the volume), keep the axis horizontal and rotate around the horizontal axis at a constant speed (for example, 25 rpm) to make it flow in the cylinder The slope of the sand layer is flat and the angle formed between the slope and the horizontal surface is measured. On the other hand, when the coated sand is wet, it does not flow in the cylinder, the slope of the coated sand layer is not formed as a flat surface, and the dynamic repose angle can not be measured, which is called wet coated sand. To be.

  In the present invention, by using the dry coated sand as described above, the pot life thereof can be extended, and the storage stability can be advantageously improved. It is possible to prepare a large amount in advance in a place such as a factory different from the field, and to transport a part of it to the molding site so that it can be used for molding of a target mold. It will be able to contribute greatly to the efficiency improvement of molding operation.

  In addition, as a refractory aggregate which comprises the above coated sands, it is a refractory substance which functions as a base material of a casting_mold | mold, Comprising: The various refractory granular thru | or powder-form materials conventionally utilized for casting_molds In particular, silica sand, regenerated silica sand, alumina sand, olivine sand, zircon sand, chromite sand and other special sands, ferrochrome-based slag, ferro-nickel-based slag, converter slag, etc. And the like; alumina-based particles, artificial particles such as mullite-based particles, and regenerated particles thereof; alumina balls, magnesia clinker and the like. In addition, even if these fireproof aggregates are new sand or regenerated sand or recovered sand used once or a plurality of times as molding sand as molding sand, furthermore, such regenerated Even mixed sand made by adding new sand to sand and recovered sand can be used without any problem. And such a fireproof aggregate will generally be used as a thing of a particle size of about 40-130 by an AFS index, Preferably, about a particle size of about 60-110.

  Moreover, the binder which coats the above-mentioned refractory aggregate 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. And although these may be used independently and may be used selecting two or more, it is preferable to use especially inorganic polymer. Moreover, these water-soluble binders may be used by diluting with water or a solvent in advance.

  And as an inorganic polymer used as such a water soluble binder, although water glass, colloidal silica, alkyl silicate, bentonite, cement etc. can be mentioned, Among them, water glass is suitably used and Become. Also, such water glass is a soluble silicate compound, and as such a silicate compound, for example, sodium silicate, potassium silicate, sodium metasilicate, potassium metasilicate, lithium silicate, ammonium silicate In particular, sodium silicate (sodium silicate) is advantageously used in the present invention.

Furthermore, such sodium silicate is generally used by being classified into the types of No. 1 to No. 5 according to the molar ratio of SiO ₂ / Na ₂ O. Specifically, sodium silicate No. 1 has a molar ratio of SiO ₂ / Na ₂ O of 2.0 to 2.3, and sodium silicate No. 2 has SiO ₂ / Na ₂ O The molar ratio is 2.4 to 2.6, and sodium silicate No. 3 is the one having a molar ratio of SiO ₂ / Na ₂ O 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. Then, sodium These silicate, other uses alone may be used as a mixture, also by mixing, it is also possible to prepare the molar ratio of SiO ₂ / Na ₂ O.

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

  In addition, the water glass used in the present invention means a solution of a silicate compound in a state of being dissolved in water, and it is used in the state of a stock solution as purchased in the market. It will be added and used in the diluted state. The solid content (water glass component) from such water glass excluding volatile substances such as water and solvent is referred to as non-volatile content, and this corresponds to the soluble silicate compound such as sodium silicate described above. It is Also, the higher the proportion of such non-volatiles (solids), the higher the concentration of the silicate compound in the water glass. Therefore, the non-volatile content of water glass used in the present invention corresponds to the ratio excluding the amount of water in the stock solution when it is constituted only with the stock solution, while the stock solution is water. When the dilution 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 It will be done.

  And although the non volatile matter in such water glass will be made into an appropriate ratio according to the kind etc. of a water glass component (soluble silicic acid compound), the ratio of 20-50 mass% is advantageous. Is preferably contained in By causing the water glass component corresponding to the non-volatile content to be appropriately present in the aqueous solution, the water glass component can be uniformly and uniformly to the fireproof aggregate at the time of mixing (kneading) with the fireproof aggregate. Can be coated, which makes it possible to advantageously mold the target mold according to the invention. If the concentration of the water glass component in the water glass becomes too low and the total amount of non-volatile components becomes less than 20% by mass, the heating temperature is increased or the heating time is increased for drying the coated sand. It is necessary to cause problems such as energy loss. In addition, when the proportion of non-volatile components in water glass becomes too high, it becomes difficult to uniformly coat the surface of the refractory aggregate with the water glass component, and the problem is also raised in the improvement of the target mold characteristics. From this point of view, it is desirable to prepare water glass in the form of an aqueous solution such 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 water-soluble binders other than the above-mentioned inorganic polymer, resol type phenol resin, furan resin, water-soluble epoxy resin, water-soluble melamine resin, water-soluble urea resin, water-soluble Unsaturated polyester resin, water-soluble alkyd resin etc. can be mentioned. In addition, it is also advantageously employed to improve the thermosetting characteristics by blending a curing agent such as an acid or an ester with the thermosetting resin. Among these thermosetting resins, the use of resol type phenol resin is preferable, and such phenol resin can be prepared by reacting phenols and formaldehydes in the presence of a reaction catalyst. . In the present invention, as such a phenol resin, a water-soluble alkali resole resin is preferably mentioned. Use of such an alkali resole resin can provide a mold that can be used in a wide range of fields such as cast iron and cast steel.

  Moreover, as saccharides which are one of the water-soluble binders, known saccharides such as monosaccharides, oligosaccharides and polysaccharides can be used, and among various monosaccharides, oligosaccharides and polysaccharides, 1 There is no problem even if the species is selected and used alone or plural species are used in combination. Among them, as monosaccharides, glucose (glucose), fructose (fructose), galactose etc. can be mentioned, and as oligosaccharides, maltose (malt sugar), sucrose (sucrose), lactose (lactose), cellobiose etc. Can be mentioned. And as polysaccharides, starch sugar, dextrin, xanthan gum, curdlan, pullulan, cycloamylose, chitin, cellulose, starch, etc. can be mentioned. Besides this, gums of plant mucilage such as gum arabic may be used, and carboxylic acids can also be used as curing agents for saccharides, particularly polysaccharides.

  Furthermore, as synthetic polymers used as a water-soluble binder, polyethylene oxide, poly-α-hydroxy acrylic acid, acrylic acid copolymer, acrylic acid ester copolymer, methacrylic acid ester copolymer, 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 And polyether-modified silicones, or modified products thereof. And these are used singly or in combination of two or more.

  Furthermore, as salts, those which solidify by adding water and then 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, as proteins, gelatin, glue and the like can be mentioned.

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

  If the amount of the water-soluble binder used is too small, the coating layer is difficult to form on the surface of the refractory aggregate, and there is a problem that it becomes difficult to solidify or cure the coated sand sufficiently. In addition, even if the amount of the water-soluble binder used is too large, extra water-soluble binder adheres to the surface of the refractory aggregate, making it difficult to form a uniform covering layer, and the coated sands are mutually different. There is also a risk of sticking and agglomeration (composite particle formation), which adversely affects mold physical properties and causes problems that make it difficult to remove the core from sand after metal casting.

  And, in the present invention, the dry coated sand formed by forming the coating layer by it on the surface of the fireproof aggregate using the above-mentioned water soluble binder is the object. In such a coating layer, it is possible to appropriately contain known additives, if necessary. In order to incorporate such an additive into the coating layer, a method of mixing a predetermined additive in advance with the water-soluble binder and then kneading or mixing it with the refractory aggregate or separately from the water-soluble binder A method is adopted in which a predetermined additive is added to the refractory aggregate, and the whole is uniformly kneaded or mixed together with the water-soluble binder.

  In the present invention, solid oxides and salts are advantageously used as one of such additives. The moisture resistance of the coated sand can be advantageously improved by the inclusion of these solid oxides and salts. Among them, as solid oxides, use of oxides of elements such as silicon, zinc, magnesium, aluminum, calcium, lead and boron is effective. In particular, among them, the use of silicon dioxide, zinc oxide, aluminum oxide and boron oxide is desirable. Further, among silicon dioxides, precipitated silica and pyrogenic silica are preferably used. On the other hand, the salts include silicofluorinated salts, silicates, phosphates, borates, tetraborates, carbonates and the like, among which zinc carbonate, basic zinc carbonate, potassium metaborate, tetraboron The use of sodium acid, potassium tetraborate is desirable. And these solid oxides and salts are generally used in the ratio of about 0.5-5 mass% with respect to the non volatile matter in a water-soluble binder.

  In addition, it is also effective to contain a coupling agent that strengthens the bond between the refractory aggregate and the water-soluble binder as another additive, for example, a silane coupling agent, a zircon coupling agent, and a titanium coupling agent. Etc. can be used. In addition, the inclusion of a lubricant contributing to the improvement of the fluidity of the coated sand is also effective, for example, waxes such as paraffin wax, synthetic polyethylene wax, montanic acid wax, stearic acid amide, oleic acid amide, erucic acid amide etc. Fatty acid amides; Alkylene fatty acid amides such as methylenebisstearic acid amide, ethylenebisstearic acid amide; stearic acid, stearyl alcohol; lead stearate, zinc stearate, calcium stearate, metal stearates such as magnesium stearate; It is possible to use acid monoglycerides, stearyl stearate, hydrogenated oils and the like. Furthermore, as a mold release agent, paraffin, wax, light oil, machine oil, spindle oil, insulating oil, waste oil, vegetable oil, fatty acid ester, organic acid, graphite fine particles, mica, vermiculite, fluorine-based mold release agent, silicone-based mold release Agents and the like can also be used. These other additives are generally contained in a proportion of 5% by mass or less, preferably 3% by mass or less, based on the non-volatile components in the water-soluble binder.

By the way, in the present invention, when producing dry coated sand prepared in advance, generally, a water-soluble binder as a caking agent is added to the fireproof aggregate together with an additive used as needed. By kneading or mixing according to a conventional method, mixing uniformly, coating the surface of the refractory aggregate with a water soluble binder, and evaporating the water of the water soluble binder, Although a method of obtaining dry powdery coated sand having room temperature fluidity is adopted, the water evaporation of the coating layer at that time is quick before solidification or curing of the water-soluble binder proceeds. Therefore, in the present invention, it is more preferable to add a water soluble binder in the form of an aqueous solution 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 is long, the mixing (kneading) cycle becomes long, the productivity decreases, and the time when the water-soluble binder is in contact with CO ₂ in the air may be long, causing problems such as deactivation. Because it becomes higher. The water content of the dry powdery coated sand thus obtained is generally about 5 to 55% by mass, preferably 10 to 50% by mass, relative to 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 prepared by adjusting the water content to 20 to 50% by mass.

  Furthermore, the refractory aggregate is preheated as one of effective means for rapidly evaporating the water in such a water-soluble binder in the process of producing such dry state coated sand, A technique is employed in which a water-soluble binder in the form of an aqueous solution is kneaded or mixed to be mixed. By kneading or mixing a water-soluble binder into this preheated refractory aggregate, the water in the water-soluble binder can be transpirationed very quickly by the heat of such refractory aggregate. Thus, the amount of water in the coated sand to be obtained can be effectively reduced, and dry powder having cold flowability can be advantageously obtained. The preheating temperature of the refractory aggregate is appropriately selected according to the water content of the water-soluble binder, the compounding amount thereof and the like, but it is generally about 100 to 160 ° C., preferably 100 to It is desirable to carry out by heating the refractory aggregate to a temperature of about 140 ° C. If the preheating temperature is too low, it is not possible to effectively perform the transpiration of water, and it takes a long time to dry, so it is desirable to adopt a temperature of 100 ° C. or higher, and it is also preferable to have the preheating temperature If the amount of C. becomes too high, curing of the water-soluble binder component proceeds during cooling of the coated sand to be obtained, and in addition composite particleization proceeds, problems with the function as coated sand, particularly physical properties such as strength Will occur.

  Then, in the present invention, after the dried coated sand obtained as described above is transported to the molding site, which is the production site of the mold, the surfactant and / or Alternatively, an aqueous medium containing a polyhydric alcohol is added to be wetted, and the obtained wetted coated sand is filled into a mold to form a target mold. The step of adding a surfactant and / or a polyhydric alcohol-containing aqueous medium to the dry-state coated sand and moistening the solution may be carried out simply by applying a dry-state coated sand and a predetermined amount of the above-mentioned aqueous medium. Since it is sufficient to wet the coated sand by putting it in the mixer and mixing it, it can be carried out with a very simple operation, and even in a molding site where the working environment is bad, it is extremely difficult. Te is as it can easily and readily carried out. In addition, by the addition of the surfactant, the compatibility between the water-soluble binder to be the coating layer of the coated sand and the water can be enhanced, and the flowability in the wet coated sand can be advantageously improved. And the improvement of the flowability improves the filling property of the coated sand to the mold, particularly in a complex mold having a long cavity path from the filling port to the filling completion, even in the mold having a long shape. It is possible to fill it. In addition, when a 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 wet coated sand is improved and the usable time is extended. It has the advantage of being able to

  Furthermore, for the purpose of wetting such dry coated sand, it is only necessary to add only the surfactant and / or the polyhydric alcohol-containing aqueous medium, and the viscous water-soluble binder is kneaded into the refractory aggregate. Since the workability is extremely good from the place where it is not carried out, and the wet coated sand hardly adheres to the mixer, the molding die and the like, the device exhibits the characteristic that the apparatus is not easily soiled. In the molding site, since the water-soluble binder, in particular, the water glass is not handled, there are also advantages such that the worker is not likely to be injured.

  Here, the surfactant and / or the 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 at a predetermined ratio. Or are prepared by dispersing. In addition, various additives indicated in this specification and other additives known to those skilled in the art will be added to and contained in the aqueous medium as required.

  And, when such an aqueous medium is added to the dry coated sand, the amount of surfactant is 0.1 to 20 parts by weight based on 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 to be 0 parts by mass, and it is preferable to use an aqueous medium to be 0.5 to 15.0 parts by mass, particularly 0.75 to 12.5 parts by mass. . In addition, as this surfactant, any of cationic, anionic, amphoteric, nonionic, silicone type and fluorine type can be used.

  Specifically, as the cationic surfactant, aliphatic amine salts, aliphatic quaternary ammonium salts, benzalkonium salts, benzethonium chloride, pyridinium salts, imidazolinium salts and the like can be mentioned. In addition, as the anionic surfactant, 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 sulfo succinate, alkyl sulfo acetate, α-olefin sulfonate, N-acyl methyl taurine, sulfated oil, higher alcohol Sulfate ester, secondary higher alcohol sulfate, alkyl ether sulfate, secondary higher alcohol ethoxy sulfate, polyoxyethylene alkyl phenyl ether sulfate, monoglysulfate, fatty acid alkylol amide sulfate, alkyl ether phosphorus Acid A stell salt, an alkyl phosphate ester salt etc. are mentioned. Furthermore, as the amphoteric surfactant, carboxybetaine type, sulfobetaine type, amino carboxylate, imidazolinium betaine and the like can be mentioned. In addition, as nonionic surfactants, polyoxyethylene alkyl ether, polyoxyethylene secondary alcohol ether, polyoxyethylene alkyl phenyl ether (for example, Emulgen 911), polyoxyethylene sterol ether, polyoxyethylene lanolin derivative , Polyoxyethylene polyoxypropylene alkyl ether (eg, Neupol 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. Further, among various surfactants, in particular, those having a siloxane structure as a nonpolar site are called silicone surfactants, and those having a perfluoroalkyl group are called fluorosurfactants. Examples of silicone surfactants include polyester-modified silicone, acrylic-terminated polyester-modified silicone, polyether-modified silicone, acrylic-terminated polyether-modified silicone, polyglycerin-modified silicone, aminopropyl-modified silicone and the like. Moreover, as a fluorochemical surfactant, perfluoroalkyl sulfonate, perfluoroalkyl carboxylate, perfluoroalkyl phosphate, perfluoroalkyl trimethyl ammonium salt, perfluoroalkyl ethylene oxide adduct, perfluoroalkyl group Included oligomers and the like. Then, these surfactants are used alone or in combination of two or more.

  In addition, the polyhydric alcohol used in place of or together with the above surfactant is generally 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 dry coated sand. The aqueous medium containing such polyhydric alcohol is preferably in the proportion of 0.5 to 15.0 parts by mass, more preferably 0.75 to 12.5 parts by mass, so that the proportion of parts is , Will be added to the coated sand. Specific examples of polyhydric alcohols used herein include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, dipropylene glycol, propylene glycol, butylene glycol, 1,2-butanediol, 1,2-pentane Diol, 1,5-pentanediol, 1,2-hexanediol, 2-ethyl-1,3-hexanediol, 1,6-hexanediol, 1,2-heptanediol, 1,2-octanediol, 1,2. 2,6-hexanetriol, thioglycol, hexylene glycol, glycerin, trimethylolethane, trimethylolpropane and the like. And these can be used individually or in mixture of 2 or more types.

  In the aqueous medium containing surfactant and / or polyhydric alcohol prepared as described above, it is possible to contain various known additives, if necessary. For example, as a curing agent, an acid or an ester may be contained, and among the acids, sulfuric acid, hydrochloric acid, carbonic acid and sulfonic acids are preferable, and as an ester, lactones such as γ-butyrolactone and ε-caprolactone, Esters derived from alcohols having 1 to 10 carbon atoms and carboxylic acids having 1 to 10 carbon atoms, such as ethylene glycol diacetate, triacetin, diethylene glycol diacetate, and triethylene glycol diacetate, are preferred. The C1-C10 alcohol at this time may be monohydric or polyvalent. Moreover, you may contain metal salts, metal powder, etc. as a hardening accelerator. Therefore, metal salts such as calcium, magnesium, aluminum and iron are preferable as the metal salt, and metal powders such as calcium, magnesium, zinc, aluminum and silicon are preferable as the metal powder. Furthermore, a drying accelerator such as alcohol which is an organic solvent such as methanol and ketones such as acetone and diacetone alcohol, and PROXEL GXL [1, 2-benzisothiazol-3 (2H) -one manufactured by Lonza Japan Co., Ltd. It is also possible to add a small amount of a preservative such as PROXEL IB (polyhexamethylene biguanidine) or a silane coupling agent.

  In addition, a second water-soluble binder can be added as a further additive to adjust 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 coated with the coated sand. No matter what. Depending on the shape and size of the mold to be produced by adding such a second water-soluble binder at the time of mold formation, if it is desired to increase the strength of the mold, a second water-soluble binder may be further added. Thus, the strength can be improved. 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 smaller than the solid content of the water-soluble binder in the coated sand. Is desirable.

  Furthermore, according to the present invention, the spherical particles are added as a further additive when moistening by adding an aqueous medium containing a surfactant and / or a polyhydric alcohol to the dry coated sand. It is also effective. By adding such spherical particles, it can be advantageously contributed to the improvement of the filling property of the coated sand at the time of mold making. Such spherical particles may be added in a mixed state to the surfactant and / or polyhydric alcohol-containing aqueous medium, and may be added separately from the surfactant and / or polyhydric alcohol-containing aqueous medium It is also possible. The amount of the spherical particles added 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, it is desirable that it is 0.75-12.5 mass parts.

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

  By the way, at the time of the wet conversion of the dry coated sand described above, a predetermined amount of a surfactant and / or a polyhydric alcohol-containing aqueous medium is added to the dry coated sand at the molding site of the mold. By mixing with a conventional mixer, the targeted wet coated sand will be formed, but the amount of water supplied by the surfactant and / or the polyhydric alcohol-containing aqueous medium used therein is The amount is suitably determined in accordance with the type and amount of the water glass component constituting the coated sand, and generally 100 parts by mass of the coated sand in order to wet the dry coated sand. In a proportion of 0.5 to 5 parts by mass, preferably in a proportion of 0.75 to 4 parts by mass, more preferably a proportion of 1 to 3 parts by mass Oite, it will be determined as appropriate. Also, the amount of surfactant and / or polyhydric alcohol-containing aqueous medium is determined by the amount of water, surfactant, or polyhydric alcohol added, but generally 100 parts by weight of coated sand The ratio is suitably determined in the proportion of 0.5 to 6 parts by mass, preferably in the proportion of 0.75 to 4 parts by mass, more preferably in the proportion of 1 to 3.5 parts by mass . If the amount of the surfactant and / or the polyhydric alcohol-containing aqueous medium added is too small, it is not possible to sufficiently achieve the wet state of the coated sand in the dry state. As the adhesion of the above becomes weak, the flowability of the coated sand becomes worse, and the filling property to the mold becomes worse, which causes problems such as a decrease in the strength of the obtained mold. On the other hand, when the addition amount of the surfactant and / or the polyhydric alcohol-containing aqueous medium is too large, in addition to the problem that the filling operation into the mold becomes difficult, the time for the drying operation after the filling into the mold It causes problems such as lengthening of molding time.

  And, according to the present invention, using the wet state of the dry coated sand obtained as described above, it is filled in a predetermined molding die, specifically the molding cavity of the molding die. By drying the moistened coated sand, a mold having an intended shape is formed. In this case, the moistened coated sand to be used directly forms the water-soluble binder. The packing property is effectively improved because the fluidity is better and the adhesion and adhesion between the sands are reduced compared to the wet coated sand obtained by kneading with the fireproof aggregate. Furthermore, adhesion to the mold can be effectively reduced, so that stains on the mold can be advantageously suppressed, and mold releasability from the mold can also be advantageously improved. is there. In addition, a blow filling method using a blow head is suitably adopted for filling such a wet coated sand into a mold, and the blow pressure at that time is about 0.2 to 0.6 MPa, Preferably, it is about 0.3 to 0.5 MPa.

  Also, as described above, when the target mold is formed by drying and solidifying or curing the wet coated sand filled in the mold, drying of the wet coated sand can be performed. 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 time of the filled wet coated sand can be advantageously shortened by effectively advancing the drying. In addition, as a heating temperature of such a shaping | molding die, the temperature within the range of 40-250 degreeC, Preferably 70-200 degreeC, More preferably, 100-175 degreeC will be employ | adopted generally. If this heating temperature is less than 40 ° C., it is difficult to sufficiently exhibit the drying acceleration effect by heating, and there is a problem that the molding time becomes long, and if it becomes higher than 250 ° C., the moisture filled in the mold is moistened. In addition to the solidification or curing of the coated sand becoming too fast and the filling property becoming worse, the wet coated sand becomes too dry, the tackiness disappears, the adhesion effect becomes low, and the mold obtained Problems such as a decrease in strength will also be caused.

  And, in order to accelerate the drying of the wet coated sand filled in the mold, it is effective to heat the filled wet coated sand directly by microwave, In particular, when the mold is a resin mold, it is suitably employed. Furthermore, drying is promoted by passing a packed bed of moistened coated sand by allowing the heated air or dry air to pass through the mold filled with the wetted coated sand, and it is filled more quickly. It is also effective to solidify or cure the wet coated sand. In addition, it is one of the effective drying means to vacuum-dry the inside of the mold by vacuum-suctioning the mold filled with the wetted coated sand, which is particularly effective for the thermal effect such as the resin mold. In molds made of easily received materials, it is advantageously employed.

  Furthermore, in the present invention, as described above, the moisture of the surfactant and / or the polyhydric alcohol-containing aqueous medium used for the moistening is prepared from the moistened coated sand filled in the mold. By removing it, the target mold is formed, in which case the water glass that constitutes the coating layer on the surface of the coated sand is usually prepared without any additives. It is solidified by evaporation to dryness of water, and if oxides, salts and the like are added as a curing agent, it will be cured. And it is also effective to let carbon dioxide gas or organic ester gas pass in the mold filled with the wetted coated sand for curing of such water glass, and this makes it possible, as in the prior art, It is possible to cure the water glass rapidly and to advantageously increase the forming speed. As organic ester gas, for example, methyl formate, ethyl formate, propyl formate, γ-butyrolactone, γ-propion lactone, ethylene glycol diacetate, diethylene glycol diacetate, glycerin diacetate, triacetin, propylene carbonate etc. are gaseous or It is atomized and used.

  According to the present invention, as a method of moistening the dry coated sand and forming it by a predetermined forming die, it is possible to manufacture a mold by adopting various known forming methods. Furthermore, the present invention can be implemented in an embodiment to which various changes, modifications, improvements, etc. are added based on the knowledge of those skilled in the art, and such embodiments do not deviate from the spirit of the present invention. It is to be understood that, to the extent, all are within the scope of the present invention.

  Hereinafter, the present invention will be more specifically clarified using some examples, but the present invention should not be construed as limiting in any way by the description of such examples. Should be understood. In the following examples and comparative examples, “%” and “parts” are all indicated on a mass basis unless otherwise noted. Moreover, the evaluation of the moisture content of the coated sand (CS) obtained by the Example and the comparative example, the filling property, the filling fluidity, and the strength was performed as follows, respectively.

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

(When the water soluble binder is water glass)
Weigh and store 10 g of each CS in a blank that has been baked and weighed, and using the mass loss (%) after heat treatment at 900 ° C. for 1 hour, the water content (W1) in CS is Calculated from the following equation (1). Weighing is measured to the fourth decimal place. Next, the binder solid content (B1) to CS is calculated using the following equation (2), and then the water content (W2) with respect to the solid content of the binder is calculated from the water content in CS by the following equation (3) Calculated using).
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 Of mass (g)]
B1 = [B2 / (100 + B2)] × (100-W1) (2)
[B1: solid content of binder to CS (%), B2: solid content of binder added to 100 parts of sand (part), W1: moisture content in CS (%)]
W2 = (W1 / B1) × 100 (3)
[W2: Water content (%) to solid content of binder, W1: Water content in CS (%), B1: Solid content of binder to CS (%)]

(When the water soluble binder is a water soluble resole resin)
Weighed 2.0 g of each CS, and contained 100 ml of Aquamicron ML (made by Mitsubishi Chemical Co., Ltd.) as a dehydrating solvent, a flask of a Karl Fischer moisture measuring machine (made by Hiranuma Sangyo Co., Ltd .: AQV-7 HIRANUMA AQUACOUNTER) [preliminarily , Karl Fischer reagent (Sigma-Aldrich Laborchemalien Gmbh: Hydranal composite 5) is dropped into the solution to keep the water to 0], and then stirred for several minutes using a magnetic stirrer, and then the above. Hydranal Composite 5 was added dropwise to quantify the amount of water (W1) in CS. Thereafter, the water content (W2) with respect to the solid content of the binder was calculated from the water content (W1) in CS using the above-mentioned formula (2) and formula (3).

-Measurement of filling property and evaluation of filling flowability-
The CSs of each of the examples or the comparative examples are each represented by one mold half 5 having a mold section as shown in FIG. 1 and the other mold half having a symmetrical mold section (5 The mold is filled at a blow pressure of 0.3 MPa from its filling port 6 and molded at a mold temperature of 150 ° C. for a molding time of 180 seconds, and the mass of the obtained mold is obtained. Measure (g). Next, in the molded mold, the filling state of CS with respect to the channels 1 to 4 in the cavity is visually evaluated. The filling state of each flow path is determined as ○: filled, Δ: filled but with some defects, x: non-filling and the portion of the channel is missing. In addition, it is filled up to the flow paths 2-4, and let the thing whose flow path 1 is filling more than (triangle | delta) be a pass.

-Measurement of bending strength-
The breaking load of a test piece having a width of 1.0 cm × height: 1.0 cm × length: 6.0 cm obtained using each CS was measured using a measuring instrument (manufactured by Takachiho Seiki Co., Ltd .: Measure using a digital foundry sand strength tester). Then, using the measured breaking load, the bending strength is calculated by the following equation (4).
Anti-folding strength (N / cm ² ) = 1.5 × LW / ab ² (4)
[L: distance between supporting points (cm), W: breaking load (N), a: width of test piece (c
m), b: thickness of test piece (cm)]

-Production Example 1 of dry CS
While preparing Lunamos # 80 (trade name: manufactured by Kao Quaker Co., Ltd.), which is a commercially available artificial sand for casting, as a refractory aggregate, a commercially available product as water glass used as a binder (water soluble binder): A No. 2 sodium silicate (trade name: manufactured by Fuji Chemical Co., Ltd., a molar ratio of SiO ₂ / Na ₂ O: 2.5, solid component: 41.3%) was prepared. Then, after the above-mentioned Lunamos # 80 is heated to a temperature of about 120 ° C., it is introduced into a Shinagawa universal stirrer (5DM-r type) (manufactured by Dalton Co., Ltd.) and the water glass is further added to 100 of Lunamos # 80. Add 1.21 parts (solid content: 0.50 parts) to each part, and perform kneading for 3 minutes to evaporate water while stirring and mixing until the sand clumps are taken out and taken out Thus, a free-flowing dry coated sand: CS1 was obtained at room temperature. When the water content of CS1 after this kneading was measured, it was 0.2% (/ CS).

-Production Example of dry CS
A commercial product No. 1 sodium silicate (trade name: made by Fuji Chemical Co., Ltd., a molar ratio of SiO ₂ / Na ₂ O: 2.1, solid component: 48.5%) is used as a water glass of a binder. And the same procedure as in Production Example 1 except that the addition amount of the water glass is set to a ratio of 1.03 parts (0.50 parts of solid component) with respect to 100 parts of Lunamos # 80. , I got dry CS2. And when the water content of CS2 after the kneading was measured, it was 0.2% (/ CS).

-Production example of dry CS
A commercial product: No. 3 sodium silicate (trade name: made by Fuji Chemical Co., Ltd., molar ratio of SiO ₂ / Na ₂ O: 3.2, solid component: 38%) is prepared as water glass of the binder, The dry state was carried out according to the same procedure as the above-mentioned Production Example 1 except that the addition amount of this water glass was set to a ratio of 1.32 parts (0.50 parts of solid component) to 100 parts of Lunamos # 80. Got a CS3. And when the water content of CS3 after the kneading was measured, it was 0.2% (/ CS).

-Production example of dry CS
A commercial product: HPR 833 (trade name: manufactured by Asahi Organic Materials Co., Ltd., non-volatile component: 45%) was prepared as a water-soluble resol which is a binder (water-soluble binder). Then, after the above-mentioned Lunamos # 80 is heated to a temperature of about 120 ° C., it is introduced into a Shinagawa universal stirrer (5DM-r type) (manufactured by Dalton Co., Ltd.) and water-soluble resol is further added to 100 of Lunamos # 80. The mixture was added at a ratio of 1.33 parts (resin component 0.6) to the part, and kneading was performed for 60 seconds to evaporate the water, while stirring and mixing until the sand globules were broken. Thereafter, by taking out from a stirrer, CS4 having a free flowing dry state was obtained at normal temperature. Moreover, when the water content of CS4 after the obtained kneading | mixing was measured, it was 0.2% (/ CS).

-Production Example 1 of wet CS
While preparing Lunamos # 80 (trade name: manufactured by Kao Quaker Co., Ltd.), which is a commercially available artificial sand for casting, as a fireproof aggregate, a commercial product: No. 2 sodium silicate (a commercial product as a water glass of a caking agent) Name: Fuji Chemical Co., Ltd.) was prepared. Next, the above-mentioned Lunamos # 80 at normal temperature is introduced into a Shinagawa universal stirrer (type 5DM-r) (manufactured by Dalton Co., Ltd.), and the water glass is further added to 100 parts of Lunamos # 80 in 1. While adding at a ratio of 21 parts (solid component 0.50 part), 0.46 parts of water was added and kneading was performed for 3 minutes to obtain CS5 in a wet state. When the water content of CS5 after this kneading was measured, it was 1.15% (/ CS), and when the dynamic angle of repose was measured, it became a wet state and did not have room temperature fluidity, The dynamic repose angle could not be measured.

-Example of mold formation-
Example 1
A commercially available product: Olfin PD-301 (trade name: manufactured by Nisshin Chemical Industry Co., Ltd.) as an anionic surfactant, 0.02 part of which is added to 2 parts of water and mixed and stirred. Thus, a surfactant-containing aqueous solution as an aqueous medium was obtained. Then, 100 parts of the CS1 obtained in the above Production Example 1 in a dry state is charged into a Shinagawa universal stirrer (5DM-r type), and a surfactant-containing aqueous solution as the aqueous medium is further added. (Thus, the surfactant ratio was 4.0 parts to 100 parts of solid content of water glass in CS1), and it was 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 the mold halves 5 heated to 150 ° C. at a gauge pressure of 0.3 MPa and filled. The After holding for 180 seconds, the mold was removed from the mold to obtain a mold as a test piece.

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

(Example 3)
An aqueous medium was obtained by adding 0.06 parts of an anionic surfactant (a ratio of 12 parts to 100 parts of the solid content of water glass) to 2 parts of water and mixing and stirring. A mold (specimen) was produced according to the same procedure as in Example 1 except for the following.

(Example 4)
A mold (specimen) was produced according to the same procedure as Example 2, except that the dry state CS1 was changed to the dry state CS2.

(Example 5)
A mold (specimen) was produced according to the same procedure as Example 2, except that the dry state CS1 was changed to the dry state CS3.

(Example 6)
As a silicone surfactant, a commercially available product: KF 643 (trade name: Shin-Etsu Chemical Co., Ltd.) is prepared, and 0.005 part thereof (the ratio of 1 part to 100 parts of solid content of water glass) A mold (specimen) was produced according to the same procedure as in Example 1 except that it was used, added to 2 parts of water, mixed and stirred to obtain an aqueous medium.

(Example 7)
A commercially available product: KF 640 (trade name: Shin-Etsu Chemical Co., Ltd.) is prepared as a silicone surfactant, and 0.005 part thereof (the ratio of 1 part to 100 parts of the solid content of water glass) A mold (specimen) was produced according to the same procedure as in Example 1 except that it was used, added to 2 parts of water, mixed and stirred to obtain an aqueous medium.

(Example 8)
A template (test piece) was produced according to the same procedure as in Example 2, except that a commercially available product: Lipolan LB-440 (trade name: manufactured by Lion Corporation) was used as the anionic surfactant.

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

(Example 10)
A mold (specimen) was produced according to the same procedure as Example 2, except that a commercially available product: Surfynol 485 (trade name: manufactured by Nisshin Chemical Industry Co., Ltd.) was used as the nonionic surfactant.

(Example 11)
A commercially available product: Olfin PD-301 (trade name: manufactured by Nisshin Chemical Industry Co., Ltd.) as an anionic surfactant, and its ratio of 4 parts to 100 parts of the solid content of water glass ) And, as a polyhydric alcohol, 0.04 parts of glycerin (the ratio of 8 parts to 100 parts of solid content of water glass) is added to 2 parts of water and mixed and stirred. Thus, according to the same procedure as in Example 1 except that an aqueous medium was used, a mold (specimen) was produced.

(Example 12)
Commercially available product: Olfin PD-301 (trade name: manufactured by Nisshin Chemical Industry Co., Ltd.) as an anionic surfactant, and 0.05 parts thereof (10 parts ratio to 100 parts solid content of water glass) ) And, as a polyhydric alcohol, 0.04 parts of glycerin (the ratio of 8 parts to 100 parts of solid content of water glass) is added to 2 parts of water and mixed and stirred. Thus, according to the same procedure as in Example 1 except that an aqueous medium was used, a mold (specimen) was produced.

(Example 13)
Commercially available product: Olfin PD-301 (trade name: manufactured by Nisshin Chemical Industry Co., Ltd.) as a surfactant, 0.05 parts thereof (10 parts relative to 100 parts solid content of water glass) Is added to 2 parts of water, and 0.05 part of spherical particles HS311 (trade name: manufactured by Nippon Steel & Sumitomo Metals Co., Ltd.), which is an aqueous medium obtained by mixing and stirring, (water glass A mold (specimen) was produced according to the same procedure as in Example 1 except that 10 parts were added to 100 parts of solid content. In addition, it was 0.91 when the aspect ratio of HS311 was measured.

(Example 14)
A mold (specimen) was produced according to the same procedure as Example 2, except that the dry state CS1 was changed to the dry state CS4.

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

(Example 16)
Polyethylene glycol commercially available product: PEG 400 (product name: Dai-ichi Kogyo Seiyaku Co., Ltd.) as a polyhydric alcohol, and its 0.04 parts (the ratio of 8 parts to 100 parts of solid content of water glass) is 2 A mold (specimen) was produced according to the same procedure as in Example 1 except that it was added to water of the part and mixed and stirred to give an aqueous medium.

(Example 17)
Obtained by adding glycerin to 2 parts of water using glycerin as a polyhydric alcohol, which is a ratio of 8 parts to 100 parts of solid content of water glass, and mixing and stirring. Add 0.05 parts of HS311 (trade name: Nippon Steel Sumikin Materials Co., Ltd.) as spherical particles (10 parts relative to 100 parts of solid content of water glass) to the aqueous medium A mold (specimen) was produced according to the same procedure as in Example 1 except that it was used.

(Example 18)
A mold (specimen) was produced according to the same procedure as Example 15, except that the dry state CS1 was changed to the dry state CS4.

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

(Comparative example 2)
The wet CS5 was placed in a blow tank, and filled into a mold heated to 150 ° C. by blowing at a gauge pressure of 0.3 MPa. Then, after being held in the mold for 180 seconds, the mold (test piece) was obtained by removing it from the mold.

(Comparative example 3)
A template (test piece) was produced according to the same procedure as in Example 14 except that ordinary 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 described above, the measurement of the filling property and the evaluation of the filling fluidity are performed according to the above-mentioned test method, and the measurement of the strength The results are shown in Tables 1 to 3 below.

  As apparent from the results of Tables 1 to 3, in Examples 1 to 18, the template obtained from CS wetted with a surfactant and / or a polyhydric alcohol-containing aqueous medium according to the present invention is It is recognized that all show good filling properties and filling flow properties of coated sand.

  On the other hand, according to Comparative Examples 1 to 3, since the dry CS is moistened using only water, or the wet CS is directly formed using water glass, molding is performed. In the case of the above-mentioned mold, it is recognized that the filling property of CS into the mold and the filling fluidity are not sufficient.

  Moreover, it is recognized that the mold obtained in Examples 1 to 18 achieves an effective improvement in strength as compared with the comparative example using CS that has been wetted by kneading only water.

1 to 4 channels 5 mold halves 6 filling ports

Claims (13)

  The dry coated sand obtained by coating the surface of the fireproof aggregate with a water-soluble binder was moistened by adding an aqueous medium comprising a surfactant and / or a polyhydric alcohol. After that, the obtained wetted coated sand is filled into a mold, and a mold is produced.   The method 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 such that the ratio of the surfactant 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. A method of manufacturing a mold according to claim 1 or claim 2.   The aqueous medium is added such that the ratio of the polyhydric alcohol 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 according to any one of claims 1 to 3, wherein   The method for producing a mold according to any one of claims 1 to 4, wherein when the dry coated sand is moistened, spherical particles are further added.   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 when the dry coated sand is moistened.   The method for producing a mold according to any one of claims 1 to 7, wherein the water content in the dry coated sand is 5 to 55% by mass of the solid content of the water soluble binder. .   9. The water-soluble binder according to claim 1, wherein one or more selected from thermosetting resins, saccharides, proteins, synthetic polymers, salts and inorganic polymers are selected and used. The manufacturing method of the mold as described in any one.   The method for producing a mold according to claim 9, wherein the inorganic polymer is water glass.   The method for manufacturing a mold according to any one of claims 1 to 10, wherein heated air or dry air is ventilated in the mold filled with the wet 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 allowed to pass through the mold filled with the wetted coated sand.   The method for manufacturing 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.