JPWO2018043413A1 - Method of manufacturing laminated mold - Google Patents

Abstract

A laminated mold capable of suppressing or preventing the spread of the spray liquid at the time of forming a two-dimensional pattern of each sand layer and capable of suppressing or preventing the deterioration or deformation of the shape of the laminated mold obtained and the deterioration of dimensional accuracy. Provide a manufacturing method of A thin sand layer 20 is formed by using a coated sand obtained by coating a refractory aggregate with a water-soluble binder, and then an aqueous medium is dispersed in the sand layer and heated to solidify or harden a predetermined two-dimensional pattern 46. The layer forming operation is repeated, and when manufacturing the three-dimensional laminated mold 36, hydrophobic liquid or water retention along the outline 40 of the two-dimensional pattern 46 prior to the formation of the two-dimensional pattern 46 by the dispersion of the aqueous medium. The liquid is sprayed to form a hydrophobic zone 42 or a water retention zone 50 of a predetermined width bordering the two-dimensional pattern 46.

Description

  The present invention relates to a method of manufacturing a laminated mold, and in particular, to form a thin sand layer, repeatedly solidify or harden it into a predetermined shape one by one, and laminate and integrate the sand layer to be solidified or hardened. The present invention relates to a method for producing a desired three-dimensional shaped sand mold.

  In recent years, a lamination molding technique by a three-dimensional printing method has been actively studied and put to practical use. Also, applying such a lamination molding technology to mold making of molds, trial manufacture of molds and manufacture of molds for high-mix low-volume production have been studied in various parts of the world, and among them, lamination by laser method or inkjet method A mold making method has been proposed. Among the laser method and the inkjet method, an inkjet method manufacturing apparatus has an advantage that the device is cheaper than the laser method.

  By the way, as a laminating method of molds by the conventional laser method, for example, a method of forming sand molds by laminating method as disclosed in JP-A-9-168840 (patent document 1) is proposed. ing. Then, in the method, a sand layer forming step of forming a thin sand layer by spraying resin-coated sand (resin coated sand), and a curing step of curing a predetermined portion of the thin layered sand layer by laser irradiation. In this way, one layer of sand mold is formed, and those steps are sequentially repeated to sequentially layer a hardened sand layer corresponding to each cross-sectional shape of the desired sand mold, and form a three-dimensional structure of sand. It is designed to mold a certain sand mold.

  Thus, in the method of forming a sand mold by the laser lamination method, the resin-coated sand is heated and cured by heating by laser irradiation. At the same time, there is an inherent problem that the odor of organic matter is generated. In addition, since the temperature difference is generated in the sand layer depending on the presence or absence of the laser irradiation, internal stress is easily generated, and there is a problem that warpage or distortion occurs when stored for a long time. Furthermore, in order to heat and cure a predetermined portion by laser irradiation, high power and precise control are required, and an expensive laser irradiation apparatus is required, and a large amount of energy is required for heating. There is also an inherent problem of becoming

  On the other hand, as a lamination molding method of a mold by an ink jet method, in JP 2011-230421 A (patent document 2), a layer forming step of forming a layer from a three-dimensional powder which contains a water-soluble polymer, and this layer formation A step of producing a layer having a product produced by dissolving the three-dimensional powder form in the molding liquid by causing the layer formed in the step to discharge the molding liquid containing water as a solvent from the ink jet head The manufacturing method of the three-dimensional molded article provided is clarified.

  However, there is a thickening / wetting agent that suppresses evaporation of water and thickens the molding solution, and a surfactant, and is contained in the used molding solution to further adjust the pH to 7-9. It is said that the desired three-dimensional molded product can be molded according to the desired shape, but when the molding liquid is discharged from the ink jet head onto the three-dimensional molded powder, the three-dimensional molded powder can be obtained. There is a problem that bleeding of the forming solution occurs in the layer of the three-dimensional shaped powder upon dissolution. Then, in the case of laminating and molding while such bleeding occurs, the contour portion of the resulting molded product becomes uneven or the dimensional accuracy deteriorates, and in particular, as shown in FIG. As in the case of obtaining the target mortar-shaped shaped product 2 shown, in the case where the upper layer is wider in the upper layer than in the lower layer as in the case of obtaining the target 2 in the mortar shape, the lower part is spread into the lower layer. Since it is easy, the problem that molding shape changes will be caused like the laminated product 4 obtained.

  In addition, if the amount of liquid discharged from the ink jet head is reduced in order to suppress the infiltration of the molding solution, the molding solution does not sufficiently spread to the originally necessary part, causing problems such as a decrease in strength of the molding. It will occur.

JP-A-9-168840 JP 2011-230421 A

  Here, the present invention is made on the background of such circumstances, and the problem to be solved is the bleeding of the spray liquid at the time of forming a two-dimensional pattern of each sand layer at the time of lamination molding. It is an object of the present invention to provide an improved method of manufacturing a laminated mold which can be advantageously suppressed or prevented, and another object of the invention is to deteriorate or deform the shape of the laminated mold to be obtained, and to obtain dimensional accuracy. It is an object of the present invention to provide a method of manufacturing a laminated mold which can advantageously suppress or prevent the deterioration of

  Under these circumstances, the present inventors repeatedly conducted intensive studies on a method for producing a desired three-dimensional laminated mold by repeating the work of forming a solidified layer or a hardened layer of a predetermined two-dimensional pattern. By providing a hydrophobic zone and a water retention zone so as to outline such a two-dimensional pattern, it has been found that the spread of the spray liquid can be effectively suppressed or prevented, and the present invention has been completed. .

  And this invention can be suitably implemented in various aspects which can be listed below, in order to solve the subject set forth above. In addition, each aspect described below can be adopted in any combination. In addition, the aspects or technical features of the present invention can be recognized based on the description of the entire specification and the inventive concept disclosed in the drawings, without being limited to what is described below. It should be understood.

(1) A thin sand layer is formed by using a coated sand obtained by coating a refractory aggregate with a water-soluble binder, and then an aqueous medium is dispersed and heated in the sand layer to form a solidified layer of a predetermined two-dimensional pattern. An operation of forming a hardened layer is repeated to laminate the solidified layer or the hardened layer, thereby producing a desired three-dimensional laminated mold, thereby dispersing the two-dimensional pattern by dispersing the aqueous medium. Along with the forming step, a hydrophobic liquid is spread to a predetermined width along the outline on the area of the sand layer which is located outside the outline of the two-dimensional pattern and to which the aqueous medium is not spread. A method for producing a laminated mold, comprising the step of forming a hydrophobic zone bordering a dimensional pattern.
(2) The method for producing a laminated mold according to the aspect (1), wherein the step of forming the hydrophobic zone is performed prior to the step of forming a two-dimensional pattern by spraying the aqueous medium.
(3) After forming a thin sand layer using coated sand obtained by coating a refractory aggregate with a water-soluble binder, a solidified layer of a predetermined two-dimensional pattern is formed by spraying an aqueous medium onto the sand layer and heating it. An operation of forming a hardened layer is repeated to laminate the solidified layer or the hardened layer, thereby producing a desired three-dimensional laminated mold, thereby dispersing the two-dimensional pattern by dispersing the aqueous medium. In the area of the sand layer to which the aqueous medium is applied, which is located inside the outline of the two-dimensional pattern along with the forming step, a water retention liquid is applied to a predetermined width along the outline, and A method of manufacturing a laminated casting mold, comprising the step of forming a water retentive zone for bordering a dimensional pattern.
(4) The method for producing a laminated mold according to the aspect (3), wherein the step of forming the water retention zone is performed prior to the step of forming a two-dimensional pattern by spraying the aqueous medium.
(5) After forming a thin sand layer using coated sand obtained by coating a refractory aggregate with a water-soluble binder, a solidified layer of a predetermined two-dimensional pattern is formed by spraying an aqueous medium onto the sand layer and heating it. An operation of forming a hardened layer is repeated to laminate the solidified layer or the hardened layer, thereby producing a desired three-dimensional laminated mold, thereby dispersing the two-dimensional pattern by dispersing the aqueous medium. In the area of the sand layer to which the aqueous medium is applied, which is located inside the outline of the two-dimensional pattern along with the forming step, a water retention liquid is applied to a predetermined width along the outline, and Forming a water retentive zone bordering the two-dimensional pattern; and in the region of the sand layer located outside the two-dimensional pattern outline where the aqueous medium is not dispersed, a hydrophobic liquid along the outline. And D. spreading the body to a predetermined width to form a hydrophobic zone bordering the two-dimensional pattern.
(6) The method according to the aspect (5), wherein the step of forming the hydrophobic zone and the step of forming the water retention zone are performed prior to the step of forming a two-dimensional pattern by spraying the aqueous medium. How to make a laminated mold.
(7) At least one hydrophobic component selected from the group consisting of an oleophilic solvent, and a normal temperature solid solvent having a melting point higher than normal temperature,
Or the manufacturing method of the lamination | stacking mold as described in said aspect (1) comprised including it, said aspect (2), said aspect (5), or said aspect (6).
(8) At least one water retaining component selected from the group consisting of alcohols, polyhydric alcohols, alcoholic hydroxyl group-containing water-soluble polymer compounds, pyrrolidone derivatives, saccharides, and metal salts. Or the above aspect (3), the above aspect (4), the above aspect (A)
5) Or the manufacturing method of the lamination | stacking mold as described in a said aspect (6).
(9) The method for producing a laminated mold according to any one of the aspects (1) to (8), wherein the aqueous medium contains a surfactant.
(10) The method for producing a laminated mold according to any one of the aspects (1) to (9), wherein the aqueous medium further contains a humectant.
(11) The above aspect (1) to the above aspect (10), wherein the coated sand obtained by coating the refractory aggregate with a water soluble binder is dry coated sand having cold flowability. The manufacturing method of the lamination mold as described in any one of these.
(12) The above aspect characterized in that the water content in the coated sand obtained by coating the refractory aggregate with a water soluble binder is 5 to 55% by mass with respect to the solid content of the water soluble binder. 11) The manufacturing method of the lamination mold as described in 11).
(13) The method for producing a laminated mold according to any one of the above aspects (1) to (12), wherein the spreading means to the sand layer is an inkjet type spreading device.
(14) One or more selected from thermosetting resins, saccharides, proteins, synthetic polymers, salts, and inorganic polymers may be selected and used as the water-soluble binder. A method for producing a laminated mold according to any one of aspects (1) to (13).
(15) The above aspect (1) wherein the inorganic polymer is water glass
4) The manufacturing method of the lamination mold as described in 4).

According to the method for manufacturing a laminated mold according to the present invention, various effects as listed below can be exhibited.
(I) At the time of formation of a two-dimensional pattern in each sand layer, a hydrophobic zone formed of a hydrophobic liquid, a water retention property formed of a water retention liquid, and the like along the contour line of the two-dimensional pattern By providing zones, the spread of the aqueous medium to be dispersed can be effectively suppressed or prevented.
(Ii) It is possible to advantageously obtain a laminated mold excellent in dimensional accuracy by suppressing deterioration and deformation of the shape of the mold obtained by laminated molding.
(Iii) In the mold obtained by lamination molding, the aqueous medium to be dispersed is sufficiently spread, whereby solidification or hardening of the sand layer can be advantageously progressed, and the mold strength is effectively improved. It will be
(Iv) The sand layer can be sprayed with an amount of aqueous medium sufficient to develop strength, without regard to the penetration of the aqueous medium to be sprayed.
(V) It is not necessary to select or adjust the concentration of the liquid component of the aqueous medium in consideration of the penetration of the aqueous medium to be sprayed into the sand layer.
(Vi) At the time of molding of a large-sized laminated mold, the liquid volume of the aqueous medium dispersed in the sand layer is also large, and the shape change is also larger. According to the present invention, such problems are advantageously solved. You can do it.

It is a schematic explanatory drawing which shows the sand layer formation process in one Embodiment of the manufacturing method of the lamination mold according to this invention, Comprising: (a) shows the state which is spreading coating sand, (b) shows spreading coating sand. It shows a state of flat development. It is a schematic explanatory drawing which shows the formation process of a hydrophobic zone following the sand layer formation process shown by FIG. FIG. 3 is an enlarged plan explanatory view showing a hydrophobic zone formed in the sand layer by spraying of a hydrophobic liquid in FIG. 2; It is a schematic explanatory drawing which shows the spraying process of an aqueous medium following the hydrophobic zone formation process shown by FIG. FIG. 5 is an enlarged plan explanatory view showing a form in which an aqueous medium is dispersed in FIG. 4 to form a two-dimensional pattern (an aqueous medium impregnated region). It is a schematic explanatory drawing which shows the heating process of a sand layer following the aqueous-medium dispersion process shown by FIG. It is a schematic explanatory drawing which shows the casting_mold | template layer which consists of a solidified layer or a hardened layer formed of the process of 1 turn which consists of the process shown by FIGS. It is a schematic explanatory drawing which shows the state which laminates | stacks and forms a lamination | stacking casting_mold | template by repeating the formation process of the casting_mold | template layer which consists of a solidified layer thru | or hardening layer of a two-dimensional pattern shown by FIG. It is a schematic explanatory drawing which shows the lamination | stacking mold obtained in embodiment of the manufacturing method of the lamination | stacking mold | mold according to this invention shown by FIGS. 1-8. It is a schematic explanatory drawing which shows the water retention zone formation process in 2nd embodiment of the manufacturing method of the lamination | stacking mold | mold according to this invention. FIG. 11 is an enlarged plan explanatory view showing a form in which a water retention zone is formed in the sand layer obtained in FIG. 10. It is a schematic explanatory drawing which shows the formation process of the hydrophobic zone in the 3rd embodiment of the manufacturing method of the lamination | stacking template according to this invention, and a water retention zone. FIG. 13 is an enlarged plan explanatory view showing a form in which a hydrophobic zone and a water retention zone are formed in the sand layer obtained in FIG. 12. FIG. 14 is an enlarged plan explanatory view showing a form in which an aqueous medium is dispersed in FIG. 13 to form a two-dimensional pattern. It is a schematic explanatory drawing which compares and shows an example of the sand mold (laminated mold) obtained by the conventional lamination molding method with the molded article of a target shape.

  Hereinafter, in order to clarify the configuration of the present invention more specifically, representative embodiments of the present invention will be described in detail with reference to the drawings.

  First, the coated sand used in the present invention is obtained by coating a refractory aggregate with a water-soluble binder. Therefore, various types of refractory aggregates conventionally used for molds are appropriately selected and used as the refractory aggregate. Specifically, silica sand, chromite sand, zircon sand, olivine sand, alumina sand, synthetic mullite sand and the like can be mentioned. Among them, spherical artificial sand is preferably used from the viewpoint of reducing the amount of binder used. In addition to these new sands, these refractory aggregates may be sands regenerated or recovered from those used one or more times as molding sands as casting sands, and further, mixed sands thereof. No matter what, no matter what. The coated sand (laminated sand) for laminated mold making obtained using these refractory aggregates is the air permeability, sanding property of the obtained mold, and a sand layer when forming the mold using it. From the relationship such as thickness, preferably the particle size index is within the range of 80 to 150, preferably 90 to 130, based on the AFS coefficient defined in the JACT test method S-1 (granularity test method for foundry sand). It is controlled to be within the range. If the particle size index is less than 80, sufficient curing strength may not be obtained, and if it exceeds 150, the air permeability of the resulting mold may be deteriorated. In addition, as the thickness of the solidified / hardened sand layer (mold layer) becomes thinner, the formation of such a thin sand layer becomes easy since the casting surface of the casting cast using the obtained mold becomes better It is desirable to use aggregate of particle size.

  And the binder which coats the above-mentioned refractory aggregate is also called a caking agent, and a water soluble binder will be 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. In addition, although these may be used independently and you may select and use two or more, especially, inorganic polymer will be used suitably. In addition, these water soluble binders may be used by diluting with water or solvent in advance.

  Here, examples of the inorganic polymer used as the water-soluble binder include water glass, colloidal silica, alkyl silicate, bentonite, cement and the like. Among them, water glass is a soluble silicate compound such as sodium silicate, potassium silicate, sodium metasilicate, potassium metasilicate, lithium silicate, ammonium silicate and the like, among which silica Sodium acid and potassium silicate are preferably used. There are various types of silicic acid compounds depending on the molar ratio, and there are, for example, 1 to 5 for sodium silicate and 1 and 2 for potassium silicate. Among these, in the casting field, water glass is mentioned as a suitable thing, and sodium silicate is particularly desirable, and it is possible to obtain a mold applied to a wide range of fields such as cast iron and cast steel.

  Further, as a thermosetting resin which is one of water soluble binders, 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. .

  And in this invention, water-soluble alkali resole resin will be used suitably as said phenol resin. In this water-soluble alkaline resole resin, in the presence of a large amount of an alkaline substance, for example, the number of moles of the alkaline substance to the phenol is about 0.1 to 3.0 times, preferably about 0.3 to 2 It is an alkaline resol-type phenolic resin obtained by reacting with aldehydes at a ratio of about 0 times mole. In addition, as an alkaline substance used there, the hydroxide of alkali metals, such as sodium hydroxide, potassium hydroxide, lithium hydroxide etc., is mentioned, for example, These are used individually or in mixture of 2 or more types It is 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 water-soluble binders, monosaccharides, oligosaccharides, polysaccharides, etc. can be used, and 1 type is chosen from various monosaccharides, oligosaccharides, polysaccharides, and it is independent. There is no problem even if it is used or in combination of two or more kinds. 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. In addition to 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 type copolymer, acrylic acid ester type copolymer, methacrylic acid ester type, polyacrylamide, anionization Polyacrylamide, cationized polyacrylamide, polyamino alkyl methacrylate, acrylamide / acrylic acid copolymer, polyvinyl sulfonic acid, polystyrene sulfonic acid, sulfonated maleic acid, polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene glycol, polyvinyl methyl ether, polyether modified silicone Or modified products of these. 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.

  In the present invention, the coated sand obtained by coating the refractory aggregate with a water-soluble binder may be either wet or dry, but it is dry coated sand having room temperature fluidity. Is desirable. The dry state of the coated sand makes it possible to evenly and evenly grind the sand when forming the sand layer.

  By the way, in the production of the coated sand used in the present invention, the compounding amount of the fireproof aggregate and the water-soluble binder is generally such that the water-soluble binder is 100% by mass of the fireproof aggregate in terms of solid content. The ratio which becomes about 0.1-5 mass parts is employ | adopted, Preferably the ratio of 0.3-3 mass parts will be employ | adopted advantageously. In the production of the coated sand, the refractory aggregate and the water soluble binder are kneaded or mixed to coat the surface of the refractory aggregate with the water soluble binder, and such water solubility It has fluidity at normal temperature so that the amount of water is 5 to 55% by mass, preferably 10 to 50% by mass, based on the solid content of the water-soluble binder, by evaporating the water of the aqueous solution of the binder To obtain a dry powdery water-soluble binder-coated refractory aggregate, but the water evaporation of such an aqueous solution of the water-soluble binder can be rapidly carried out before the curing of the water-soluble binder proceeds. It is necessary to be carried out, and in general, the contained water is removed within 5 minutes, preferably within 2 minutes, to obtain a dry powdery water-soluble binder-coated refractory aggregate.

  Therefore, in the present invention, as one means for rapidly evaporating the water in the aqueous solution of such a water soluble binder, the refractory aggregate is preheated, and the aqueous solution of the water soluble binder is kneaded therein The method of mixing is advantageously employed. By kneading or mixing a water-soluble binder aqueous solution with the preheated refractory aggregate, the water of the water-soluble binder aqueous solution is rapidly evaporated by the heat of the heated fire-resistant aggregate. As a result, the water content of the water-soluble binder-coated refractory aggregate can be reduced efficiently, 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 aqueous solution of the water-soluble binder, the compounding amount thereof and the like, but generally 100 to 200 ° C., preferably 120 It is desirable to heat to a temperature of about -180 ° C. If the preheating temperature is too low, it will be difficult to effectively evaporate water, and if the preheating temperature is too high, there is a possibility that the curing of the water-soluble binder may proceed. And although the water content of the coated sand obtained in this way changes the range of becoming dry depending on the addition amount of the water-soluble binder to the fireproof aggregate, generally, the solid content of the water-soluble binder On the other hand, the water content is preferably about 5 to 55% by mass, and more preferably 10 to 50% by mass. Among them, in the case where the water-soluble binder is water glass, 20 to 50% by mass is desirable. As a result, the coated sand becomes a powder of free-flowing dry state, and has excellent characteristics to which normal temperature fluidity is imparted.

  In the production of the above-mentioned coated sand, together with the refractory aggregate and the water-soluble binder, various known additives such as a coupling agent, a mold release agent and a solvent can be blended, if necessary, It will be used as a coating sand which contains such an additive. In the present invention, it is also possible to mix and use other powders in the obtained coated sand, and in this case, after being wet with an aqueous medium, the powder used is It is not particularly limited as long as it solidifies or cures by heating and drying. The various additives may be added in advance during or after the production of the water-soluble binder.

  By the way, the method for producing a laminated mold according to the present invention is carried out, for example, as shown in FIG. 1 to FIG. 9 using the coated sand obtained as described above. That is, first, as shown in FIG. 1, in the mold forming apparatus of the mold used in the present invention, a rectangular table 12 vertically slidable in the vertical direction in a container-like frame 10 having a square planar shape. Is arranged. Further, as shown in FIG. 1, FIG. 2 and FIG. 4, such a molding apparatus is provided at a lower portion of the storage tank 16 for supplying the coated sand 14 positioned above the frame 10. The spreadable sand 14 supplied to the upper surface of the table 12 is spread thinly to a constant thickness from the spouted outlet 18 to form a thin sand layer 20, and a predetermined liquid is sand layer by an inkjet method An ink jet spraying device 26 as selective spraying means for spraying to a predetermined site on 20 and a heater 30 provided with a heating wire 32 as a heating element are provided according to the respective steps of mold layer production. Are selectively switched and arranged.

  There, the ink jet spreader 26 is provided with nozzles 28a, 28b, 28c which can be moved separately along the upper surface of the sand layer 20, as shown in FIGS. 2, 4 and 10, together with a storage and control device not shown. It is possible to spray separately depending on each liquid (hydrophobic liquid, aqueous medium and water-retaining liquid) used, and in this case, the hydrophobic liquid is sprayed from the nozzle 28a, and the nozzle 28b is also dispersed. From there, the aqueous medium is sprayed, and the water retaining liquid is sprayed from the nozzle 28c. In the storage device, a predetermined two-dimensional pattern (planar shape) of a predetermined mold layer 34 (see FIGS. 7 and 8) formed in each sand layer 20 is stored as an image signal, and the control device The respective liquids can be jetted (dispersed) to each sand layer 20 in a predetermined plane shape (pattern) while controlling the operation of the nozzles 28a, 28b, 28c according to the image signal. ing. Here, switching of the equipment in each process is automatically performed, but of course, it is also possible to switch the switching manually or semi-automatically.

  Further, although the heater 30 shown in FIG. 6 is configured to be able to heat using the heating wire 32 as a heating element, various known heating elements for such heating wire 32 can be used. Is selected appropriately and may be used, for example, using metal carbide (nichrome wire, Kanthal wire, platinum wire etc.), silicon carbide, molybdenum disilicide, lanthanum chromite, molybdenum, carbon etc. It is also possible to heat it. The heater 30 is not particularly limited as long as it can be heated, and an infrared generator, a microwave generator, or the like can also be used.

  In the embodiment to be described above, the selective spraying unit configured by the inkjet spraying device 26 selectively sprays a liquid such as a hydrophobic liquid or an aqueous medium to a predetermined position on the sand layer 20. In the apparatus thus obtained, advantageously, an ink jet type dispersing apparatus as illustrated is used, but in addition, a predetermined liquid is dispersed only to the necessary part of the sand layer 20 using a mask. It is also possible to appropriately adopt a mask-type sprayer or the like that is configured as described above.

  Then, as one method for producing the desired laminated mold according to the present invention using the apparatus as described above, the following production procedure A is adopted to produce the mold layer 34, and further the mold layer The lamination integration of 34 results in the formation of the lamination mold 36 (the target mold).

(1) Production procedure A (in the case of using a hydrophobic liquid)
<First step>
First, in the stage before manufacture, the upper surface of the frame 10 of the molding apparatus and the upper surface of the table 12 are positioned on the same plane. Then, when the molding process starts, the table 12 is slid downward by the height of the sand layer 20. Next, the coated sand 14 stored in the storage tank 16 is evenly spread on the table 12 with a substantially uniform thickness while the supply amount from the discharge port 18 is controlled, as shown in FIG. 1A. To be supplied. At this time, the height per one layer of the sand layer 20 is formed as a step corresponding to the distance by which the table 12 slides downward, for example, a step of 0.5 mm. In addition, it is desirable that this level | step difference is formed so that it may always become uniform height for every layer laminated | stacked, and it is desirable to generally be set as a level | step difference of about 0.1 mm-3 mm.

  Then, when the supply of the coating sand 14 onto the table 12 is finished, the extension member 24 is horizontally moved along the upper surface of the frame 10 as shown in FIG. Is scraped off. Thereby, the sand layer 20 developed thin and flat on the table 12 is formed with a predetermined thickness.

Second step
Then, as shown in FIG. 2, from the nozzle 28 a of the ink jet spreader 26 toward the sand layer 20, a two-dimensional pattern in which the hydrophobic liquid 38 in the form of mist gives the target mold layer 34 (see FIG. 7) A band-like hydrophobic zone is applied to a sand layer 20 area outside the outline 40 of the sand and to which the aqueous medium to be described later is not dispersed, and is dispersed to a predetermined width along the outline 40 42 will be formed. Note that such a defined two-dimensional pattern is one in which the shape of the target mold is horizontally divided into a plurality of regions at equal intervals of the thickness of the sand layer, according to the mold to be manufactured For each sand layer, the hydrophobic liquid 38 is sprayed based on the two-dimensional pattern (planar shape) of each layer in order from the bottom. This is obtained, for example, by obtaining sand-shaped shape data from CAD data of product shapes and setting it as cross-sectional shape data for each thickness of the sand layer to set a predetermined two-dimensional pattern (planar shape) of each layer You can do it. Also, the hydrophobic zone 42 formed by the hydrophobic liquid 38 sprayed to the outside of the contour 40 at this time is generally formed along the contour 40 in a band width of 0.1 mm to 5 mm. It will be. In the ink jet spraying device 26, the nozzle diameter of the nozzle 28a for spraying the hydrophobic liquid 38 is an extremely small diameter of, for example, about 5 to 100 μm.

  By the way, as described above, the hydrophobic liquid 38 sprayed from the nozzle 28a is not particularly limited as long as it is liquid showing hydrophobicity, and it is generally used as a value showing hydrophobicity. / A liquid whose LogP value, which is a Log value of water distribution coefficient, is 0 or more is used, preferably 2 to 12, more preferably 4 to 10, and specifically, the parent It is selected from the group consisting of an oily solvent and a solvent which is solid at normal temperature having a melting point higher than normal temperature. Moreover, it is also possible to use these hydrophobic liquids individually or in combination combining 2 or more types.

The above-mentioned hydrophobicity LogP means the common logarithm of the distribution coefficient P, and how a certain chemical substance is in the equilibrium of oil (generally 1-octanol) and water. It is a physical property value which shows whether it is distributed as a quantitative numerical value, and is represented by the following formula (1).
LogP = Log (C _oil / C _water ) (1)
In the formula (1), C _oil represents the molar concentration in the _oil phase, and C _water represents the molar concentration in the aqueous phase. When the LogP value increases to the positive side across 0, it means that the oil solubility increases, and on the other hand, when it becomes negative and the absolute value increases, it means that the water solubility increases. This LogP value is negatively correlated with the water solubility of a chemical substance, and is widely used as a parameter for estimating hydrophilicity and hydrophobicity. In addition, LogP values, in principle, are actually measured in the distribution experiment in consideration of the definition, but it is considered that estimation from the structural formula is an effective means because the experiment itself takes time and effort. For this reason, the LogP value which is an estimated value of LogP by calculation is used abundantly, and it is possible to use the estimated value by such calculation also in the present invention.

  In addition, since the hydrophobic liquid used in the present invention is solid at normal temperature or high in viscosity at low temperature, the sprayed hydrophobic liquid 38 is maintained at a temperature higher than normal temperature. Is desirable. For this reason, the temperature of the hydrophobic liquid is in a temperature range of about 30 ° C. to 200 ° C., more preferably about 60 ° C. to 150 ° C. The hydrophobic liquid kept under such high temperature is suitable for spraying It will be used for

  As described above, the lipophilic solvent used in the present invention is a solvent having a Log P value of 0 or more, and specifically, pentanol, heptanol, octanol, phenylethyl alcohol, phenylpropyl alcohol, furfuryl Alcohols such as anil alcohol, cetyl alcohol, oleyl alcohol and octadecyl alcohol; ethylene glycol diacetate, ethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether acetate, propylene glycol diacetate, ethyl acetate, propyl acetate, butyl acetate, amyl acetate , Benzyl acetate, phenylethyl acetate, phenoxyethyl acetate, ethyl phenylacetate, benzyl propionate, ethyl benzoate, butyl benzoate Butyl laurate, isopropyl myristate, triethyl phosphate, tributyl phosphate, tri (2-ethylhexyl) phosphate, triphenyl phosphate, tricresyl phosphate, diethyl phthalate, dibutyl phthalate, diundecyl phthalate, diethyl malonate, Dipropyl malonate, diethyl diethylmalonate, diethyl succinate, dibutyl succinate, diethyl glutarate, diethyl adipate, dipropyl adipate, dibutyl adipate, di (2-methoxyethyl) adipate, diethyl sebacate, diethyl maleate , Esters of dibutyl maleate, dioctyl maleate, diethyl fumarate, dioctyl fumarate, 3-hexenyl cinnamic acid, tributyl citrate etc .; butyl phenyl ether, benzyl ethyl ether, hexyl ester Ethers such as ethers; ketones such as benzyl methyl ketone, benzyl acetone, diacetone alcohol, cyclohexanone, etc .; aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, petroleum ethers, petroleum benzyl, tetralin, decalin, tasha Hydrocarbons such as lyamyl benzene and dimethyl naphthalene; Amides such as N, N-diethyldodecane amide and N, N-dibutyldodecane amide; fluorine compounds such as fluorine oil and polytetrafluoroethylene; silicone oil and silicone Examples thereof include organic silicic acid compounds such as resins, chlorosilane compounds, alkoxysilane compounds, fluorosilicone compounds, and polyorganosiloxanes having a polyoxyalkylene unit.

  The normal temperature solid solvent having a melting point higher than normal temperature, which is used in the present invention, is a solvent which is in a solid or semi-molten state at normal temperature (23 ° C.) and is heated and sprayed from a spraying apparatus such as an inkjet system. And a phase change solvent which becomes a molten liquid state. The normal temperature solid solvent having a melting point higher than such normal temperature is not particularly limited, and the phase change temperature in the solid-liquid phase change of the solid solvent is higher than normal temperature, and is generally 60 ° C to 200 ° C. Among these, those having a temperature of 80 ° C. to 150 ° C. are more preferable.

  Specific examples of normal temperature solid solvents having a melting point higher than normal temperature include beeswax, carnauba wax, rice wax, wood wax, jojoba oil, spermaceti wax, candelilla wax, lanolin, montan wax, ozokerite Natural waxes such as ceresin, paraffin wax, microcrystalline wax and petrolactam; palmitic acid, stearic acid, behenic acid, tiglic acid, 2-acetonaphthone behenic acid, organic substances such as 12-hydroxystearic acid and dihydroxystearic acid Acids; Organic acid esters such as esters of the above-mentioned organic acids with glycerol, diethylene glycol, ethylene glycol and the like alcohols; dodecanol, tetradecanol, hexadecanol, eicosanol, docosanol, tetracosanol, hexacosa , Octacosanol, dodecenol, myricyl alcohol, tetracenol, hexadecenol, eicosenol, docosenol, pine glycol, hinokiol, butindiol, nonanediol, isophthalyl alcohol, mesicerine, terephtharyl alcohol, hexanediol, decanediol, dodecanediol , Alcohols such as tetradecanediol, hexadecanediol, docosanediol, tetracosanediol, TVneol, phenylglycerin, eicosandiol, octanediol, phenylpropylene glycol, bisphenol A, paraalpha cumylphenol, etc .; Acetobenzene, Benzophenone, Trichosanone, Heptacosanone, Heptatria Contanone, Hen Riacontanone, stearone, laurone, ketones such as dianisole; oleic acid amide, lauric acid amide, stearic acid amide, ricinoleic acid amide, palmitic acid amide, tetrahydrofuranic acid amide, erucic acid amide, myristic acid amide, 12-hydroxystearic acid amide , N-stearyl erucic acid amide, N-oleyl stearic acid amide, N, N'-ethylene bis lauric acid amide, N, N'-ethylene bis stearic acid amide, N, N'-ethylene bis oleic acid amide, N, N'-methylenebisstearic acid amide, N, N'-ethylenebisbehenic acid amide, N, N'-xylylene bisstearic acid amide, N, N'-butylenebisstearic acid amide, N, N'-dioleyl amide Adipic acid amide, N, N'-distear Lil adipamide, N, N'-dioleyl sebacic acid amide, N, N'-stearyl sebacic acid amide, N, N'-distearyl terephthalic acid amide, N, N'-distearyl isophthalic acid amide, phenacetin, Reaction products of dimer acid with diamine and fatty acid such as toluamide, acetamide, dimer of oleic acid / ethylenediamine / stearic acid (molar ratio of 1: 2: 2), amides such as tetraamide; para-toluenesulfonamide , Sulfonamides such as ethyl benzene sulfonamide, butyl benzene sulfonamide; silicones such as silicone SH 6018 (Toray Silicone), silicones KR 215, 216, 220 (Shin-Etsu Silicone); cumarones such as esclone G-90 (Nippon Chemical Co., Ltd.) Cholesterol; stearic acid, Cholesterol fatty acid esters such as cholesterol lumitate, cholesterol myristate cholesterol, behenic acid cholesterol, lauric acid cholesterol, myric acid cholesterol, etc .; Sucrose stearate, sucrose palmitate, saccharose behenate, saccharose laurate, sucrose mesylate sucrose, lactose stearate, Sugar fatty acid esters such as lactose palmitate, lactose myristate, lactose behenate, lactose lauric acid, lactose myric acid, etc .; polyethylene wax derivatives, chlorinated hydrocarbons, phenolic resins, thermoplastic resins and the like.

<Third step>
Then, for the sand layer 20 (see FIG. 3) in which the hydrophobic zone 42 having a predetermined width is formed as described above, as shown in FIG. 4, mist form from another nozzle 28b of the ink jet spraying device 26. The aqueous medium 44 is sprayed over the entire area of the aqueous medium distribution area surrounded by the outline 40. Note that such spraying of the aqueous medium 44 is carried out for each minute area with respect to the inner aqueous medium dispersion area surrounded by the contour line 40, and the whole of the aqueous medium dispersion area to be made to be described above. The aqueous medium 44 is sprayed to form a two-dimensional pattern 46 moistened to the aqueous medium 44, as shown in FIG. In this manner, in the two-dimensional pattern 46 formed by the aqueous medium 44 sprayed to a specific area of the sand layer 20, the aqueous medium 44 wets the coated sand 14 to wet the coated layer of the coated sand 14 The water-soluble binder, when dissolved in the aqueous medium 44, covers the refractory aggregate and the water-soluble binder comes to agglomerate between the sand grains, and thereby is a spread area of the aqueous medium 44. The coated sands 14 in the two-dimensional pattern 46 are in a state of adhering or sticking to each other.

  In addition, since the aqueous medium 44 dispersed in this way easily penetrates the sand layer 20 formed by the coated sand 14, bleeding is easily caused, and the aqueous medium 44 penetrates to a portion other than the dispersed area. (See Fig. 15). Here, the contoured portion of the two-dimensional pattern 46 is bordered by the hydrophobic liquid 38 and the rim of the hydrophobic zone 42 of a predetermined width is applied. The penetration of the medium 44 is from the two-dimensional pattern 46 (specifically the contour line 40) to the outside from where the water will be repelled by the hydrophobic liquid 38 present in the bordered hydrophobic zone 42. The bleeding of the aqueous medium 44 is effectively prevented.

  In addition, since such bleeding can be prevented, deterioration and deformation of the target mold shape can be effectively prevented, and a mold having the dimensional accuracy as designed can be advantageously obtained. Moreover, it is not necessary to adjust the amount and composition of the spray of the aqueous medium in order to suppress the spread due to the permeation of the sprayed aqueous medium, and the aqueous medium is sufficiently spread for the formation of the mold layer. From the place where it can be sprayed, there is a feature that the strength of the molded mold can be effectively improved. In particular, in molding of a large mold, it also has a feature capable of advantageously preventing the deterioration of the set shape caused by the increase in the amount of aqueous medium used.

<Fourth process>
Thereafter, for the sand layer 20 in which the two-dimensional pattern 46 is formed inside the hydrophobic zone 42 by the dispersion of the aqueous medium 44, as shown in FIG. The heater 30 provided with the heat wire 32 is disposed, and the heat of the heater 30 causes the sand layer 20 to be heated, thereby drying the wet coated sand 14. Thus, in the third step, the coating sand 14 is wetted with the aqueous medium 44 to dissolve the water-soluble binder of the coating layer, and the moisture of the wet coating sand 14 is absorbed from the adhered state. As shown in FIG. 7, one mold layer 34 is formed by evaporating and solidifying or curing the refractory aggregates provided with the water-soluble binder in a state of being bonded to each other. It will be. At this time, since the portion wetted with the sprayed aqueous medium 44 has a better heat conductivity than the non-wetted portion, heating is performed so that only the portion wetted with the aqueous medium of the coated sand 14 is It is possible to efficiently solidify or cure.

  In the fourth step, the heating by the heater 30 is to dry and solidify or harden the coated sand 14 forming the two-dimensional pattern 46, so that the sand layer 20 is heated to 30 to 180 ° C., preferably 60 to 150. It is sufficient if it can be heated to a temperature of about 80 ° C. to 140 ° C., more preferably about 100 ° C. to 120 ° C. Therefore, a large temperature difference does not occur in the sand layer 20. Therefore, the warp of the hardened sand layer can be effectively suppressed. In addition, since heating or curing may proceed at a relatively low temperature of about 100 ° C. at that time, conventional coated sand is generated by heating to a high temperature (about 200 ° C. to 300 ° C.). The odor can be effectively suppressed. Furthermore, as described above, since the heater 30 does not have to have a high output, the feature of requiring less energy consumption for heating is also exhibited.

  When the sand layer 20 is heated and dried as described above, such drying can be promoted by performing the process in an atmosphere of heated air. As another method, it is possible to carry out the above-mentioned drying operation in an atmosphere containing carbon dioxide or a gasified ester, or in an atmosphere of an inert gas such as nitrogen, in particular The use of carbon or gasified esters can facilitate the curing of the water soluble binder. In addition, as ester used by this gasification, for example, methyl formate, ethyl formate, propyl formate, gamma-butyrolactone, gamma-propion lactone, ethylene glycol diacetate, diethylene glycol diacetate, glycerin diacetate, triacetin, propylene carbonate etc. These compounds are used in the form of gas or mist.

<Repetitive process>
Then, with the process of forming the mold layer 34 consisting of a series of processes of the first process, the second process, the third process and the fourth process described above as one turn, the table 12 is further divided by the height of one sand layer. After sliding downward (the state of FIG. 7), by repeating the turn of the mold layer forming step, a new mold layer 34 is integrally formed on one mold layer 34 already formed. Thus, a laminated structure is realized. Furthermore, by repeating the formation of such a mold layer 34 several times, as shown in FIG. 8, the mold layers 34 are sequentially laminated and integrated, thereby forming a number of mold layers 34. A laminated mold 36 giving the mold of the desired shape is manufactured as shown in FIG. Thereafter, by removing the non-solidified / hardened coated sand 14 from the molding apparatus (frame 10), the desired laminated mold 36 is taken out.

(2) Production procedure B (in the case of using a water-retaining liquid)
Moreover, in the present invention, a manufacturing procedure is obtained by changing only the second step as follows while adopting the first step, the third step, the fourth step and the repeating step in the above-mentioned manufacturing procedure A as they are. According to B, it is possible to produce the desired laminated mold. In this production procedure B, a water-retaining liquid is used to spread it along the contour in a region of the sand layer, to which the aqueous medium is to be sprayed, which is located inside the contour of the two-dimensional pattern. Then, the step of forming a belt-like water retentive zone bordering the two-dimensional pattern from the inside is adopted as the second step, specifically, the formation of the water retentive zone is performed as follows: Become.

Second step
As shown in FIG. 10, a mist-like water retention liquid 48 is sprayed toward the sand layer 20 from another nozzle 28 c different from the above-mentioned nozzles 28 a and 28 b of the ink jet spraying device 26. In contrast to the second step in the previous manufacturing procedure A, as shown in FIG. 11, such an outline is located in the area of the sand layer 20 to which the aqueous medium is sprayed, which is located inside the outline 40 of the two-dimensional pattern. By spreading the water retaining liquid 48 to a predetermined width along the line 40, a belt-like water retaining zone 50 is formed, which border the two-dimensional pattern from the inside. Here, the water-retaining liquid sprayed on the inside of the contour line 40 is sprayed in a strip shape generally at a width of 0.1 mm to 5 mm, as in the case of the spraying of the hydrophobic liquid. The nozzle diameter of the nozzle 28c that jets the water retention liquid 48 is, as with the nozzles 28a and 28b described above, an extremely small diameter of about 20 to 100 μm.

  And, with respect to the sand layer 20 having the water retention zone 50 of a predetermined width formed by the spray of the water retention liquid 48 in this way, further, in the third step, similarly to the production procedure A described above, When the medium 44 is sprayed from the nozzle 28 b of the ink jet spreader 26 over the entire area inside the contour line 40, the aqueous medium 44 is also sprayed so as to overlap the strip water retentive zone 50. It will be. Thus, there, the sprayed water-based medium 44 is absorbed by the water-retaining liquid that constitutes the water-retention zone 50 that internally borders the contoured portion of the two-dimensional pattern 46, and outward from the contour 40 of the water-based medium 44. Penetration of the two-dimensional pattern 46 can be effectively prevented, and the bleeding of the aqueous medium 44 from the outline 40 of the two-dimensional pattern 46 can be advantageously prevented. Moreover, the water-retentive liquid 48 dispersed in the water-retention zone 50 contributes to the dissolution of the water-soluble binder as well as the aqueous medium 44, since it is water-soluble. Sand particles are effectively adhered to each other by the water-soluble binder dissolved out by the medium, and even in the water retention zone 50, solidification or curing is promoted in the same manner as sand particles in the region of the inner two-dimensional pattern 46. As a result, the target template layer 34 is advantageously formed.

  In addition, as a water-holding liquid used in the second step of such a production procedure B, any liquid-absorbing component that absorbs water and exhibits water-holding ability can be used without particular limitation, for example, It is selected from non-lipophilic alcohols, polyhydric alcohols, alcoholic hydroxyl group-containing water-soluble polymer compounds, pyrrolidone derivatives, saccharides, metal salts and the like. And these water retention components can be used individually or in mixture of 2 or more types. Among them, alcohols, polyhydric alcohols, pyrrolidone derivatives, water-soluble polymers and the like are suitably used. Moreover, these water retention components can be used after dilution with water in the range having water retention, and the concentration thereof is 10% by mass or more, preferably 15% by mass or more, more preferably 20% by mass or more The upper limit of the concentration is appropriately determined by the properties of the water-retaining liquid (component), and if there is no problem as to the properties, it is also possible to use it as it is without dilution with water .

  Here, examples of alcohols used as the water-holding liquid (component) include methanol, ethanol, propanol, isopropanol, butanol, isobutanol, secondary butanol, tertiary butanol, pentanol, cyclohexanol, benzyl alcohol and the like. And polyhydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, dipropylene glycol, propylene glycol, butylene glycol, 1,2-butanediol, 1,2-pentanediol, 1 5-pentanediol, 1,2-hexanediol, 2-ethyl-1,3-hexanediol, 1,6-hexanediol, 1,2-heptanedilide Lumpur, 1,2-octanediol, 1,2,6-hexanetriol, thioglycol, hexylene glycol, glycerin, trimethylol ethane, can be mentioned trimethylolpropane.

  Further, among the water-soluble polymer compounds, the alcoholic hydroxyl group-containing water-soluble polymer compound refers to a compound having 5 to 25 alcoholic hydroxyl groups per 1000 molecular weight. As such an alcoholic hydroxyl group-containing water-soluble polymer compound, for example, vinyl alcohol polymers such as polyvinyl alcohol and various modified products thereof; alkyl cellulose, hydroxyalkyl cellulose, alkyl hydroxyalkyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose etc. Cellulose derivatives, and starch derivatives such as alkyl starch, carboxyl methyl starch, oxidized starch and the like.

  Furthermore, as pyrrolidone derivatives, for example, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, 2-pyrrolidone, 5-methyl-2-pyrrolidone and the like can be mentioned. . Furthermore, examples of saccharides include monosaccharides, oligosaccharides, polysaccharides, etc. Among them, monosaccharides are saccharides that can not be further decomposed into simple saccharides by hydrolysis, preferably They are tricarbon sugars (monosaccharides having 3 carbon atoms) to dodecacarbon sugars (monosaccharides having 10 carbon atoms), more preferably hexacarbon sugars (monosaccharides having 6 carbon atoms). In addition, as metal salts, sodium chloride, sodium sulfate, calcium chloride, magnesium chloride, silicates and the like can be mentioned.

(3) Production procedure C (in the case of combined use of a hydrophobic liquid and a water retention liquid)
Furthermore, in the present invention, the objective laminated mold according to the production procedure C employing the second step of providing the hydrophobic zone 42 and the water retention zone 50 on both sides of the contour line 40 of the two-dimensional pattern. It is also characterized by the production of H. Specifically, the following second step is adopted. The first step, the third step, the fourth step and the repeated steps are carried out in the same manner as in the above-mentioned production procedure A.

Second step
That is, as shown in FIG. 13, while forming the hydrophobic zone 42 of a predetermined width outside the outline 40 of the two-dimensional pattern, the water retention zone 50 of a predetermined width is formed inside the outline 40. As shown in FIG. 12, the hydrophobic liquid 38 and the water-retaining liquid 48 are sand layers 20 respectively in the same manner as in the above manufacturing procedures A and B using the nozzles 28a and the nozzles 28c of the ink jet sprayer 26. It is sprayed on the predetermined site of. The order of formation of the hydrophobic zone 42 and the water retention zone 50 formed by spraying the hydrophobic liquid and the water retention liquid is not particularly limited, and it depends on the type of hydrophobic liquid or the water retention liquid. It will be selected appropriately. In addition, as the width of the hydrophobic zone 42 and the water retention zone 50 formed in such a manner, as in the above-described manufacturing procedures A and B, the width is about 0.1 mm to 5 mm. .

  Then, as shown in FIG. 13, with respect to the sand layer 20 in which the belt-like hydrophobic zone 42 and the belt-like water retention zone 50 are provided on both sides of the contour line 40, in the third step , B, the aqueous medium 44 is sprayed from the nozzle 28 b of the inkjet spreader 26 in the frame of the contour line 40, and such an aqueous medium 44 causes the two-dimensional pattern 46 to be as shown in FIG. Although it will be formed, it was sprayed there by being double bordered by the hydrophobic liquid 38 and the water retentive liquid 48 on both sides of the contour line 40 of the two-dimensional pattern 46 Penetration of the aqueous medium 44 can be reliably prevented by the hydrophobic zone 42 and the water retention zone 50 formed by the hydrophobic liquid and the water retention liquid. That is, the presence of the belt-like water retention zone 50 formed by the spraying of the water retention liquid 48 absorbs the water of the sprayed aqueous medium, and the penetration of the aqueous medium 44 not absorbed there is a It is more reliable that the aqueous medium 44 bleeds outward from the contour line 40 of the two-dimensional pattern 46 from the point where the water is repelled by the hydrophobic zone 42 formed by the hydrophobic liquid on the outside. Can be prevented.

  By the way, as the aqueous medium 44 sprayed from the nozzle 28 b of the ink jet sprayer 26 in each of the third steps of the manufacturing procedures A, B and C described above, a medium mainly composed of water, preferably a surfactant And those further containing a moisturizing agent are preferably employed. By including a surfactant in the aqueous medium 44, it is possible to adjust the surface tension to the sand layer 20 to improve the wettability to the coated sand 14, and by containing a humectant, it is possible to use an aqueous medium. Drying of the aqueous medium, and clogging of the nozzle 28b due to the drying and solidification of the aqueous medium can be advantageously prevented. In addition, as water to be used, pure water, tap water, distilled water, industrial water, etc. can be used without particular limitation as long as dust, dirt, etc. is not mixed, but among them, pure water can be used. Alternatively, the use of distilled water is desirable from the viewpoint of preventing clogging of the nozzle. In the case of containing the above-mentioned surfactant, it is used in a proportion of about 0.01 to 3 parts by mass with respect to 100 parts by mass of water, and in the case of containing a moisturizer, It will be used in the ratio of about 1-10 mass parts with respect to 100 mass parts of water.

  And, as a surfactant to be contained in such an aqueous medium, a cationic surfactant, an anionic surfactant, an amphoteric surfactant, a nonionic surfactant, a silicone surfactant and a fluorine-based interface Any surfactant may be used, and examples of cationic surfactants include aliphatic amine salts, aliphatic quaternary ammonium salts, benzalkonium salts, benzethonium chloride, pyridinium salts, imidazolinium salts, etc. As an anionic surfactant, fatty acid soap, N-acyl-N-methylglycine salt, N-acyl-N-methyl-β-alanine salt, N-acyl glutamate, alkyl ether carboxylate , Acylated peptide, alkyl sulfonate, alkyl benzene sulfonate, alkyl naphthalene sulfonate, dialkyl Sulfosuccinate salt, alkyl sulfoacetate, α-olefin sulfonate, N-acylmethyltaurine, sulfated oil, higher alcohol sulfate, secondary higher alcohol sulfate, alkyl ether sulfate, second And higher alcohol ethoxy sulfate, polyoxyethylene alkyl phenyl ether sulfate, monoglysulfate, fatty acid alkylolamide sulfate, alkyl ether phosphate, alkyl phosphate and the like. Furthermore, examples of amphoteric surfactants include carboxybetaine type compounds, sulfobetaine type compounds, aminocarboxylic acid salts, imidazolinium betaines, etc. In addition, as nonionic surfactants, it is possible to use polyoxyethylene surfactants. Alkyl ether, polyoxyethylene secondary alcohol ether, polyoxyethylene alkyl phenyl ether (eg, 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 Ter, polyethylene glycol fatty acid ester, fatty acid monoglyceride, polyglycerin fatty acid ester, sorbitan fatty acid ester, propylene glycol fatty acid ester, sucrose fatty acid ester, fatty acid alkanolamide, polyoxyethylene fatty acid amide, polyoxyethylene alkylamine, alkylamine oxide, acetylene Glycol, acetylene alcohol and the like can be mentioned. 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. Of course, it goes without saying that the present invention is not limited to the surfactants exemplified above, and in addition to the case of using them alone, it is also possible to use two or more kinds in combination.

  In addition, a humectant added to an aqueous medium together with or in place of such a surfactant absorbs a certain amount of water, so long as it has a moisturizing property that can suppress drying. It is not limited. Although it is possible to use the same moisturizing agent as the above-described water retaining liquid in terms of performance, the purpose of the moisturizing agent is to prevent the drying of the aqueous medium. It is not necessary and, therefore, the concentration in the aqueous medium can be lower compared to the water-holding liquid. Specifically, it is possible to use dilution with water so that the concentration of the humectant is less than 10% by mass, preferably 1 to 9% by mass, and more preferably 3 to 7% by mass. And as such a moisturizer, alcohols similar to the above-mentioned water-retaining liquid, polyhydric alcohols, pyrrolidone derivatives, water-soluble polymers, saccharides, metal salts and the like can be mentioned, among which ethylene glycol, Diethylene glycol, polyethylene glycol, propylene glycol, glycerin, pyrrolidone and the like will be suitably used.

  Furthermore, if the viscosity characteristic of the aqueous medium 44 is within a predetermined viscosity range, a curing agent such as an acid or ester contributing to the curing of the water-soluble binder or a curing accelerator may be added or various properties may be imparted. It is also possible to add and contain a small amount of an agent or the like. Among them, as the acid, sulfuric acid, hydrochloric acid, carbonic acid and sulfonic acids are preferable, and as the ester, lactones such as γ-butyrolactone and ε-caprolactone, ethylene glycol diacetate, triacetin, diethylene glycol diacetate, triethylene glycol diacetate Esters derived from alcohols having 1 to 10 carbon atoms and carboxylic acids having 1 to 10 carbon atoms are preferable. The C1-C10 alcohol at this time may be monohydric or polyvalent. In addition, a drying accelerator such as alcohol which is an organic solvent such as methanol and ketones such as acetone and diacetone alcohol, PROXEL GXL [1, 2-benzisothiazol-3 (2H) -one] manufactured by Lonza Japan Co., Ltd. And the addition of preservatives such as PROXEL IB (polyhexamethylene biguanidine). The viscosity of the aqueous medium is generally 50 cP or less, preferably 30 cP or less, more preferably 10 cP or less, in order to prevent clogging of the nozzle 28 b.

  In the above embodiment, the ink jet sprayer 26 is used as the liquid spray means, and hydrophobic liquid, aqueous medium or water-retaining liquid is applied to a predetermined portion of the sand layer 20 from the nozzles 28a, 28b or 28c respectively. In the present invention, such an ink jet spraying device 26 is suitably used as a selective spraying means, but to the extent that too much liquid is sprayed. The method and apparatus are not particularly limited as long as a suitable amount of liquid can be dispersed to the sand layer 20 so that the coated sand 14 of the sand layer 20 is wetted. Or, a system (apparatus) for spraying the liquid in the form of mist or spraying the liquid in the form of vapor is adopted appropriately.

  Further, in the above production procedure A, the step of forming the two-dimensional pattern 46 by sprinkling the aqueous medium 44 after the step of forming the hydrophobic zone 42 is carried out, but like printing by an inkjet printer, The two-dimensional pattern is thinly sliced from one side to the other, and the hydrophobic liquid and the aqueous medium are sprayed from one side at the positions where they should be sprayed, with appropriate switching, and finally the hydrophobic zone It is also possible to adopt a method (simultaneous formation of the hydrophobic zone 42 and formation of the two-dimensional pattern 46 simultaneously) of simultaneously completing the dispersed two-dimensional pattern 46 of 42 and the aqueous medium. Furthermore, in the production procedure C, after the water retention zone 50 is formed in advance, the formation of the hydrophobic zone 42 and the formation of the two-dimensional pattern 46 by the dispersion of the aqueous medium 44 are performed in the same manner as described above. Is also possible.

  Furthermore, the two-dimensional pattern 46 of the upper sand layer 20 is wider (larger) than the two-dimensional pattern 46 of the lower sand layer 20, which may cause the spread of the aqueous medium to the lower sand layer 20. In some cases, hydrophobic liquid may also be applied to the area of the lower sand layer 20 where such aqueous media may bleed, to prevent such aqueous media from bleeding. It is possible.

  Furthermore, after producing a laminated mold, the laminated mold is subjected to secondary firing for about 0.2 to 2 hours, preferably for 0.5 to 1 hour, in a thermostatic bath heated to 100 to 200 ° C. It may be done. By performing this secondary firing, it is possible to accelerate the solidification or curing of the laminated mold and improve the strength of the obtained laminated mold.

  In the following, some examples of the present invention will be shown to clarify the present invention more specifically, but the present invention is not limited by any description of such examples. Is, of course. In addition to the specific examples described above, the present invention also includes various changes and modifications based on the knowledge of those skilled in the art without departing from the spirit of the present invention, in addition to the specific description described above. It should be understood that improvements, etc. may be added. In the following examples and comparative examples, parts and percentages are all based on mass unless otherwise noted. Further, the measurement of the bending strength and the dimensional accuracy, the appearance determination and the measurement of the water content in the coated sand (hereinafter abbreviated as CS) in the following Examples and Comparative Examples were performed as follows.

-Measurement of bending strength-
The breaking load of a test piece (laminated molded product) having a size of width 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.) : Calculated using a digital casting sand strength tester). Then, using the measured breaking load, the bending strength is calculated by the following equation.
Breaking strength (N / cm ² ) = 1.5 × LW / ab ²
[L: distance between supporting points (cm), W: breaking load (N), a: width of test piece (c
m), b: thickness of test piece (cm)]

-Measurement of dimensional accuracy-
Using each CS, a test piece (laminated molded product) of a size of width 30 mm × height 10 mm × length 85 mm is molded, its width is measured three times with a caliper, and the average of the obtained measured values is obtained The dimensional accuracy is calculated by the value of “average value of actual measurement” ÷ “design value”. As the dimensional accuracy is closer to 1, it indicates that the accuracy is better.

-Appearance judgment-
The appearance of the obtained laminate-molded product is evaluated by visually observing a test piece obtained by laminating and molding a size of width 30 mm × height 10 mm × length 85 mm from each CS. And, when the surface of such a laminated molding is flat and the corner is firmly formed, ○, some unevenness of the surface is recognized, but when the corner is formed, Δ, the surface is uneven and the corner is also If it is rounded, evaluate it as x.

-Measurement of water content in CS-
The method is not particularly limited as long as it is a method capable of measuring the water content in CS, and an effective measuring method can be selected depending on the type of binder. An example of the selection method is shown below.

(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. Hydratal composite 5 is added dropwise to quantify the water content (W1) in CS. Thereafter, the water content (W2) with respect to the solid content of the binder is calculated from the water content (W1) in CS using the above-mentioned formula (2) and formula (3).

-Production Example 1 of CS-
While preparing Lunamos # 110 (trade name: manufactured by Kao Quaker Co., Ltd.), which is a commercially available artificial sand for casting, as a refractory aggregate, a commercial product: sodium silicate No. 2 (as a water-soluble binder) Brand name: Fuji Chemical Co., Ltd., the molar ratio of SiO ₂ / Na ₂ O: 2.5, solid component: 41.3%) was prepared. Then, the above-mentioned Lunamos # 110 heated to a temperature of about 180 ° C. is introduced into a Shinagawa universal stirrer (5DM-r type) (manufactured by Dalton Co., Ltd.), and further, the water glass is 100 parts of Lunamos # 110. The mixture is added at a ratio of 4.84 parts (solid content: 2.0 parts), and kneading is performed for 3 minutes to evaporate water, and after stirring and mixing until the sand globules are broken, it is taken out As a result, a free flowing CS1 was obtained at room temperature. Moreover, it was 25.6% when the water content with respect to the binder solid content in CS after kneading | mixing was measured.

-Production Example of CS 2-
As a water-soluble resol resin of a water-soluble binder, a commercial product: HPR 833 (trade name: manufactured by Asahi Organic Materials Co., Ltd., non-volatile component: 45%) was prepared. Then, after the above-mentioned Lunamos # 110 heated to a temperature of about 150 ° C. is put into a Shinagawa universal stirrer (5DM-r type) (manufactured by Dalton Co., Ltd.), the above-mentioned water-soluble resole resin is further added. The mixture was added at a ratio of 5.56 parts (2.5 parts of the resin component) to 100 parts of the mixture, and kneading was performed for 60 seconds to evaporate the water, while stirring and mixing until the sand globules were broken. Thereafter, by taking it out of the stirrer, CS2 having a free flowing dry state was obtained at normal temperature. Moreover, it was 26.3% when the water content with respect to the binder solid content in CS after this kneading | mixing was measured.

-Example 1-
Using the molding apparatus having the frame (10) and the table (12) as shown in FIG. 1 and the CS1 obtained above, the lamination molding was performed according to the above-mentioned production procedure A. First, in the first step, the table (12) was slid downward by 0.5 mm, and then CS1 was developed thinly on the table (12) to form a sand layer (20). Next, in the second step, from the nozzle (28a) of the ink jet sprayer (26), the hydrophobic liquid (38) in the form of mist is put on the outside of the 30 mm x 85 mm rectangular two-dimensional pattern outline (40). Sprayed in a width of 3.0 mm to form a band of hydrophobic zones (42). The hydrophobic liquid used here is paraffin wax (manufactured by Nippon Seiwa Co., Ltd.), which was maintained at 70 ° C. and used in a liquid state.

  Next, in the third step, from the nozzle (28b) of the ink jet sprayer (26) shown in FIG. 4, the misty aqueous medium (44) is drawn into a 30 mm × 85 mm rectangular two-dimensional pattern outline (40) The entire inner part of the spray. In addition, 1.0% of anionic surfactant (Orphin PD-301: made by Nisshin Chemical Industry Co., Ltd.) and 5.0% of glycerin (humectant) are added to the aqueous medium (44) with respect to water. It was used while maintaining the temperature at 40.degree. Furthermore, in the fourth step, as shown in FIG. 1, a heater (30) provided with a heating wire (32) is disposed above the sand layer (20) after the aqueous medium has been sprayed, and such a heater (30) Heat the sand layer (20) under the heat of) to solidify by drying the wet CS to obtain a mold layer (34) of a size corresponding to the shape of the two-dimensional pattern (46). The

  The thickness (height) of the laminated mold (laminated mold 36) becomes 10 mm, with the series of processes consisting of the above first process, second process, third process and fourth process as one turn. Lamination of the mold layer (34) is repeated until the mold strength (34) of the obtained laminated mold (36) is measured for the bending strength and the dimensional accuracy, respectively, the results are shown in Table 1 below.

-Example 2-
A layered mold (36) was produced in the same manner as in Example 1 except that the hydrophobic liquid used in Example 1 was changed to hydrocarbons AF-4 (trade name: Shin Nippon Oil Co., Ltd.). Then, the flexural strength and dimensional accuracy of the obtained laminated mold (36) were measured, and the results are shown in Table 1 below.

Example 3
In the same manner as in Example 1 except that the hydrophobic liquid used in Example 1 was changed to silicone oil SH 200 (product name: Toray Dow Corning Co., Ltd.), a laminated mold (36) was produced. Then, the flexural strength and dimensional accuracy of the obtained laminated mold (36) were measured, and the results are shown in Table 1 below.

Example 4
The hydrophobic liquid in Example 1 is changed to polyethylene glycol (product name: PEG 400, Dai-ichi Kogyo Seiyaku Co., Ltd.), which is a water-retaining liquid, according to the above-mentioned production procedure B, and the outline of the two-dimensional pattern (40) A laminated mold (36) was produced in the same manner as in Example 1 except that the spray was changed from the outside to the inside. Then, the flexural strength and dimensional accuracy of the obtained laminated mold (36) were measured, and the results are shown in Table 1 below.

Example 5
The water-retaining liquid used in Example 4 is changed to a 10% aqueous solution of polyvinyl alcohol (trade name: Denkapobar K-05, Denka Co., Ltd.), and from the outside to the inside of the contour line (40) of the two-dimensional pattern. A laminated mold (36) was produced in the same manner as in Example 1 except that the spray was changed to Then, the flexural strength and dimensional accuracy of the obtained laminated mold (36) were measured, and the results are shown in Table 1 below.

Example 6
A combination of the hydrophobic liquid paraffin wax (made by Nippon Seiwa Co., Ltd.) used in Example 1 and the polyethylene glycol (product name: PEG 400, Dai-ichi Kogyo Seiyaku Co., Ltd.) of the water retaining liquid used in Example 4 Then, after performing double bordering as shown in FIG. 13 according to the above-mentioned production procedure C, in the same manner as in Example 1, spraying of the aqueous medium (third step), heating of the sand layer (20) The fourth step) and lamination of the mold layer (34) (repeating step) were performed to produce a laminated mold (36). The widths of the hydrophobic zone (42) and the water retention zone (50) formed along the contour (40) were 3.0 mm and 3.0 mm, respectively. Then, the flexural strength and dimensional accuracy of the obtained laminated mold (36) were measured, and the results are shown in Table 1 below.

-Example 7-
Example except that the aqueous medium of Example 1 was added with only 1.0% of an anionic surfactant (Orphin PD-301: manufactured by Nisshin Chemical Co., Ltd.) with respect to water. In the same manner as 1), a laminated mold (36) was produced. Then, the flexural strength and dimensional accuracy of the obtained laminated mold (36) were measured, and the results are shown in Table 1 below.

-Example 8-
A laminated mold (36) was produced in the same manner as in Example 1 except that the aqueous medium of Example 1 was one in which only glycerol (humectant) at 5.0% was added to water. . Then, the flexural strength and dimensional accuracy of the obtained laminated mold (36) were measured, and the results are shown in Table 2 below.

-Example 9-
A laminated mold (36) was produced in the same manner as in Example 1 except that CS1 used in Example 1 was changed to CS2. Then, the flexural strength and dimensional accuracy of the obtained laminated mold (36) were measured, and the results are shown in Table 2 below.

Example 10
A laminated mold (36) was manufactured in the same manner as in Example 4 except that CS1 used in Example 1 was changed to CS2. Then, the flexural strength and dimensional accuracy of the obtained laminated mold (36) were measured, and the results are shown in Table 2 below.

Comparative Example 1
A laminated mold (36) was produced in the same manner as in Example 1 using only the aqueous medium without forming the hydrophobic zone (42) using the hydrophobic liquid in Example 1. Then, the flexural strength and dimensional accuracy of the obtained laminated mold (36) were measured, and the results are shown in Table 2 below.

Comparative Example 2
The laminated template (36) was prepared in the same manner as in Example 1, except that the aqueous medium was dispersed only as water without forming the hydrophobic zone (42) using the hydrophobic liquid in Example 1. Manufactured. Then, the flexural strength and dimensional accuracy of the obtained laminated mold (36) were measured, and the results are shown in Table 2 below.

Comparative Example 3
CS1 used in Comparative Example 1 was changed to CS2, and in the same manner as Comparative Example 1, a laminated mold (36) was produced. Then, the flexural strength and dimensional accuracy of the obtained laminated mold (36) were measured, and the results are shown in Table 2 below.

Comparative Example 4
CS1 used in Comparative Example 2 was changed to CS2, and in the same manner as Comparative Example 2, a laminated mold (36) was produced. Then, the flexural strength and dimensional accuracy of the obtained laminated mold (36) were measured, and the results are shown in Table 2 below.

  As apparent from the results of Tables 1 and 2, each of the laminated molds (36) obtained in Examples 1 to 10 according to the present invention has excellent bending strength and high dimensional accuracy, Moreover, also in the appearance, it recognized that it was a molding having a flat surface and firm corners. On the other hand, the laminated molds (36) obtained in Comparative Examples 1 to 4 are slightly inferior in bending strength, moreover, the dimensional accuracy is poor, and also in the appearance observation, the surface irregularities and corners are rounded. Were recognized.

DESCRIPTION OF SYMBOLS 2 Molded product 4 Laminated product 10 Frame 11 Molding hole 12 Table 14 Coating sand 16 Reservoir tank 18 Discharge port 20 Sand layer 24 Stretching member 26 Ink jet spraying device 28a, 28b, 28c Nozzle 30 Heater 32 Heating wire 34 Mold layer 36 Laminated mold 38 Hydrophobic Liquid 40 Contour line 42 Hydrophobic zone 44 Aqueous medium 46 Two-dimensional pattern 48 Water retention liquid 50 Water retention zone

Claims (15)

A thin sand layer is formed using coated sand obtained by coating a refractory aggregate with a water-soluble binder, and then the sand layer is dispersed and heated with an aqueous medium to solidify or harden a predetermined two-dimensional pattern. By repeating the process of forming the solid layer and the hardened layer to form a desired three-dimensional laminated mold,
Along with the step of forming the two-dimensional pattern by the dispersion of the aqueous medium, the area of the sand layer not dispersed with the aqueous medium, which is located outside the outline of the two-dimensional pattern, is hydrophobic along the outline A method of manufacturing a laminated mold, comprising the steps of: spraying a liquid to a predetermined width to form a hydrophobic zone bordering the two-dimensional pattern.   The method for producing a laminated mold according to claim 1, wherein the step of forming the hydrophobic zone is performed prior to the step of forming a two-dimensional pattern by spraying the aqueous medium. A thin sand layer is formed using coated sand obtained by coating a refractory aggregate with a water-soluble binder, and then the sand layer is dispersed and heated with an aqueous medium to solidify or harden a predetermined two-dimensional pattern. By repeating the process of forming the solid layer and the hardened layer to form a desired three-dimensional laminated mold,
Along with the step of forming the two-dimensional pattern by the dispersion of the aqueous medium, the area of the sand layer, to which the aqueous medium is dispersed, located inside the outline of the two-dimensional pattern is retained along the outline A method of manufacturing a laminated mold, comprising the steps of: spraying a sex liquid to a predetermined width to form a water retentive zone bordering the two-dimensional pattern.   The method according to claim 3, wherein the step of forming the water retention zone is performed prior to the step of forming a two-dimensional pattern by spraying the aqueous medium. A thin sand layer is formed using coated sand obtained by coating a refractory aggregate with a water-soluble binder, and then the sand layer is dispersed and heated with an aqueous medium to solidify or harden a predetermined two-dimensional pattern. By repeating the process of forming the solid layer and the hardened layer to form a desired three-dimensional laminated mold,
Along with the step of forming the two-dimensional pattern by the dispersion of the aqueous medium, the area of the sand layer, to which the aqueous medium is dispersed, located inside the outline of the two-dimensional pattern is retained along the outline Applying a hydrophobic liquid to a predetermined width to form a water retentive zone bordering the two-dimensional pattern; and outside the outline of the two-dimensional pattern in the area of the sand layer to which the aqueous medium is not distributed. And b. Spreading hydrophobic liquid to a predetermined width along the contour line to form a hydrophobic zone bordering the two-dimensional pattern.   The method for producing a laminated mold according to claim 5, wherein the step of forming the hydrophobic zone and the step of forming the water retention zone are respectively performed prior to the step of forming a two-dimensional pattern by spraying the aqueous medium.   The at least one hydrophobic component selected from the group consisting of an oleophilic solvent and a normal temperature solid solvent having a melting point higher than normal temperature is included in or contained in the hydrophobic liquid. The manufacturing method of the lamination mold according to claim 2, claim 5 or claim 6.   The water-retaining liquid is at least one water-retentive component selected from the group consisting of alcohols, polyhydric alcohols, alcoholic hydroxyl group-containing water-soluble polymer compounds, pyrrolidone derivatives, saccharides, and metal salts, or The manufacturing method of the lamination | stacking mold of Claim 3, 4 or 5 or 6 comprised.   The method for producing a laminated mold according to any one of claims 1 to 8, wherein the aqueous medium contains a surfactant.   The method for producing a laminated mold according to any one of claims 1 to 9, wherein the aqueous medium further contains a humectant.   The coated sand obtained by coating the refractory aggregate with a water-soluble binder is a dry-type coated sand having room temperature fluidity, according to any one of claims 1 to 10. Method of manufacturing laminated mold.   12. The laminate according to claim 11, wherein the water content of the coated sand formed by coating the refractory aggregate with a water soluble binder is 5 to 55% by mass with respect to the solid content of the water soluble binder. Manufacturing method of mold.   The method for producing a laminated mold according to any one of claims 1 to 12, wherein the spreading means to the sand layer is an ink jet type spreading device.   One or two or more selected from thermosetting resins, saccharides, proteins, synthetic polymers, salts, and inorganic polymers are selected and used as the water-soluble binder. Item 14. A method for producing a laminated mold according to any one of items 13.   The method for producing a laminated mold according to claim 14, wherein the inorganic polymer is water glass.

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