JP6121120B2 - Mold manufacturing method - Google Patents

Description

  The present invention relates to a method for producing a mold used for casting.

  Conventionally, there are various types of mold manufacturing methods, and one of them is a shell mold method. The shell mold method is obtained by molding a refractory aggregate for molds such as cinnabar with a binder, and has excellent characteristics such as obtaining a mold with good dimensional accuracy. Has been used a lot.

  As the binder for the shell mold, a thermosetting resin such as a phenol resin is generally used. A fire-resistant aggregate and a thermosetting resin are mixed to form a thermosetting resin on the surface of the fire-resistant aggregate. Prepare coated binder refractory (generally called resin-coated sand), fill this binder-coated refractory into a heated mold, and melt and cure the thermosetting resin binder. Thus, a mold can be formed.

  In the binder-coated refractory, as the thermosetting resin binder for coating the surface of the refractory aggregate, it is common to use a phenol resin as described above, and among the phenol resins, a novolac type phenol resin is used. Is often used. Since this novolak type phenol resin is thermoplastic and does not cure even when heated, it is common to use hexamethylenetetramine as a curing agent (see, for example, Patent Document 1).

  When a binder-coated refractory prepared using a novolac-type phenolic resin as a binder is filled in a mold heated to 250 to 350 ° C., it is heated by heat transfer from the mold and hexamethylenetetramine is converted into formaldehyde and ammonia. Most of the formaldehyde can be reacted with the novolac type phenolic resin to cure the phenolic resin into an insoluble and infusible state.

  However, formaldehyde and most ammonia that did not contribute to the reaction would be volatilized into the atmosphere when molding the mold or after molding. However, there is a problem that the environment is polluted. When a resol type phenol resin is used as the phenol resin, such a problem can be somewhat reduced. However, since the unreacted formaldehyde is also released in the resol type phenol resin, the problem still remains.

  In addition, when casting the molten metal into a mold using a binder-coated refractory having a phenol resin as a binder, the phenol resin is decomposed by the heat of the molten metal, for example, phenol, xylenol, toluene, benzene, Methane etc. will be released, and in this respect as well, not only the health of workers but also environmental pollution becomes a problem. Furthermore, phenol resin has high heat resistance and a large amount of residual carbon. Therefore, when casting a casting by injecting molten metal into the mold, it is difficult for the mold to collapse due to the heat of the molten metal, and the casting is removed from the mold. In addition, it is necessary to apply an impact to the mold or to decompose the phenol resin by heating at a high temperature for a long time, and there is a problem that it takes time and effort to remove the mold.

  Thus, it has been proposed to use a binder-coated refractory material in which a saccharide, a water-soluble inorganic compound, or a water-soluble thermoplastic resin is coated on the surface of the refractory aggregate as a binder (see Patent Documents 2 and 3). Saccharides, water-soluble inorganic compounds, and water-soluble thermoplastic resins become sticky when dissolved or swollen in water and become wet, and can be used as a binder for caking a binder-coated refractory. . These saccharides, water-soluble inorganic compounds, and water-soluble thermoplastic resins are free from problems such as formaldehyde release as in the case of phenol resins, and can provide a mold having good disintegration.

  However, if saccharides, water-soluble inorganic compounds, and water-soluble thermoplastic resins are coated on the surface of the refractory aggregate in a wet state, the fluidity of the binder-coated refractory deteriorates, and the binder-coated refractory is It becomes difficult to fill the mold, and poor filling is likely to occur. Therefore, in Patent Documents 2 and 3, the surface of the refractory aggregate is coated with a solid binder by coating with a binder containing a saccharide, a water-soluble inorganic compound, and a water-soluble thermoplastic resin and then drying. Binder coated refractories are used.

  In manufacturing a mold using such a binder coated refractory coated with a binder composed of a solid saccharide, a water-soluble inorganic compound, and a water-soluble thermoplastic resin, The inside is filled with a binder-coated refractory, and molding is performed through water vapor in the mold. That is, when water vapor is blown into a mold filled with a binder-coated refractory, the temperature of the water vapor decreases due to contact with the binder-coated refractory, the water vapor condenses, and the condensed water becomes viscous on the surface. Supplied to the binder. When moisture is supplied to a solid binder composed of sugars, water-soluble inorganic compounds, and water-soluble thermoplastic resins, the binder dissolves or swells in water and becomes wet, thereby causing stickiness. The binder-coated refractory particles can be bonded to each other by the adhesiveness of the binder. Next, due to the condensation latent heat and sensible heat of water vapor passed through the mold, the binder-coated refractory in the mold is heated, and the water contained in the binder evaporates to form the binder. A mold in which the particles of the binder-coated refractory are bonded with the solidified and solidified binder can be obtained.

JP 2002-346691 A JP 2012-76113 A JP 2012-115870 A

  As described above, in Patent Documents 2 and 3, the mold is filled with a binder-coated refractory coated with a solid binder made of sugar, water-soluble inorganic compound, and water-soluble thermoplastic resin, and water vapor is formed. By passing through the mold, water vapor is condensed on the surface of the binder-coated refractory to replenish moisture to the binder, causing the binder to have a sticking action and caking the particles of the binder-coated refractory. After caking by the adhesive action of the agent, the moisture of the binder is continuously evaporated by heating with condensation latent heat and sensible heat of water vapor passed through the mold, and the binder is dried and solidified. A mold in which particles of the binder-coated refractory are bonded with a solidified binder is formed.

  Here, water vapor used industrially can be obtained by boiling water by heating water with a boiler or the like. Water vapor at 100 ° C. is obtained under atmospheric pressure, and water vapor at a high temperature of 100 ° C. or higher is obtained in a pressurized state, and the water vapor concentration is substantially 100% saturated water vapor. Although superheated steam may be used, superheated steam is obtained by heating saturated steam to a temperature higher than that temperature, and even in this case, the steam concentration is substantially 100%.

  As described above, the water vapor industrially used in the mold manufacturing facility has a water vapor concentration of 100% or close to it, and contains a large amount of water. For this reason, when water vapor is passed through a mold filled with a binder-coated refractory, the water vapor is condensed to produce condensed water, and this condensed water is used to produce solid sugar, water-soluble inorganic compound, water-soluble It is possible to exert an adhesive action on a binder made of a thermoplastic resin.

  However, when the water content in the water vapor is large, condensed water is generated in an amount more than that necessary to bring the binder into a wet state and cause an adhesive action. And if the condensed water is generated excessively in the mold, the binder coated refractory is caulked by the adhesive action of the binder that has absorbed the condensed water, and then passed through the mold. When heating the binder-coated refractory with water vapor to evaporate the condensed water and drying and solidifying the binder, it takes a long time to dry until the binder solidifies. There was a problem that time became long.

  In addition, when a large amount of condensed water is generated in the mold, the binder of the binder-coated refractory may be dissolved in the condensed water and flowed, and the binder may move. . When the binder moves and is unevenly distributed in the mold in this way, there arises a problem that the strength of the molded mold may vary.

  The present invention has been made in view of the above points, and provides a method for producing a mold that can shorten the molding time of the mold, improve the strength of the mold, and stabilize the quality. It is intended.

The method for producing a mold according to the present invention comprises filling a molding die with a binder-coated refractory coated with a solid binder that has a sticking action in a wet state where moisture has been absorbed, and has a temperature of 50 to 500 ° C. By passing a high-temperature and high-humidity gas having a water vapor concentration of 10 to 60 % through the mold, moisture generated by condensation of water vapor in the high-temperature and high-humidity gas is used as a binder on the surface of the binder-coated refractory. Replenish and bind the binder-coated refractory with the adhesive action of the binder, and continue heating in a high-temperature and high-humidity gas with the same temperature and water vapor concentration as above and passed through the mold. The moisture of the agent is evaporated, and the binder is dried and solidified.

  When a high-temperature high-humidity gas is passed through a mold filled with a binder-coated refractory, the high-temperature high-humidity gas comes into contact with the binder-coated refractory and the temperature drops, and water vapor in the high-temperature high-humidity gas condenses. The condensed water produced is supplied to the binder, and the particles of the binder-coated refractory can be bonded to each other with the binder produced by absorbing the moisture of the condensed water. Then, the binder-coated refractory in the mold is heated by the high-temperature and high-humidity gas that is continuously passed through the mold to evaporate the water contained in the binder, and the binder is removed. It is possible to obtain a mold that can be solidified, and in which the binder-coated refractory particles are bonded with the solidified binder.

The high-temperature and high-humidity gas passed through the mold has a temperature of 50 to 500 ° C. and a water vapor concentration of 10 to 60 %. Therefore, the moisture content in the high-temperature and high-humidity gas is determined by sticking the binder to a wet state. It is sufficient to provide an action, and is much less than the water vapor used in the past, and it is not rare that a large amount of excess condensed water is generated in the mold, and the condensed water is evaporated. Thus, the time for drying and solidifying the binder can be shortened, and the molding time of the mold can be shortened. In addition, since a large amount of excess condensed water is not generated in the mold in this way, the binder of the binder coated refractory is not washed away by the condensed water, and the binder is unevenly distributed. Thus, a mold having a uniform strength can be produced.

  In the present invention, as the binder, those selected from saccharides, water-soluble inorganic compounds, and water-soluble thermoplastic resins can be used.

  Saccharides, water-soluble inorganic compounds, and water-soluble thermoplastic resins are free from environmental pollution problems such as formaldehyde emission as in the case of using a phenol resin as a binder. Saccharides are easily decomposed by heat during casting, and water-soluble inorganic compounds and water-soluble thermoplastic resins are readily soluble in water, both of which produce molds with good disintegration. It is something that can be done.

  In the present invention, the high-temperature and high-humidity gas is a mixed gas of water vapor and air.

  By using a mixed gas containing water vapor in the air as the high-temperature and high-humidity gas, the high-temperature and high-humidity gas prepared at low cost can be used to produce a mold at low cost.

  Moreover, this invention can use what was prepared by adjusting the mixing ratio and mixing water vapor and gas as said high temperature, high humidity gas.

  By adjusting the mixing ratio of water vapor and gas, a high-temperature and high-humidity gas having a target water vapor concentration can be easily prepared.

  Moreover, superheated steam can be used as said steam. Since superheated steam has a large thermal energy, the moisture absorbed in the binder can be quickly evaporated, and the molding time of the mold can be further shortened.

  Moreover, in this invention, what was prepared by vaporizing water in gas can be used as said high temperature, high humidity gas.

  By evaporating water in the gas, a high-temperature and high-humidity gas in which water vapor is mixed with the gas can be easily prepared.

  In the present invention, the binder-coated refractory filled in the mold may be preheated to a temperature lower than the dew point temperature of the high temperature and high humidity gas.

  By preheating the binder-coated refractory in this way, it is possible to prevent the temperature of the high-temperature and high-humidity gas that is passed through the mold from being cooled by the binder-coated refractory and dropping too much. The temperature of the high-humidity gas does not drop too much and excessive condensed water is not generated.

  In the present invention, the mold temperature of the mold may be set to a temperature lower than the dew point temperature of the high temperature and high humidity gas.

  By setting the mold temperature of the mold to be lower than the dew point temperature of the high temperature and high humidity gas in this way, condensed water can be easily generated from the high temperature and high humidity gas even in the vicinity of the mold surface of the mold. Adhesive action can be achieved by supplying sufficient moisture to the binder of the binder coated refractory in the part of the mold that comes into contact with the mold surface. It is possible to prevent that.

  In the present invention, the water vapor concentration of the high-temperature and high-humidity gas may be adjusted so as to decrease with time and may be passed through the mold.

  In this way, since the water vapor concentration of the high-temperature and high-humidity gas is high in the initial stage of passing the high-temperature and high-humidity gas through the mold, condensed water is easily generated from the high-temperature and high-humidity gas, and the caking of the binder-coated refractory is performed. The agent can be moistened to ensure that the adhesive action is exerted, and at the end of passing the high-temperature high-humidity gas through the mold, the water vapor concentration of the high-temperature high-humidity gas is low, so the condensed water is evaporated. The efficiency is high, and the time for drying and solidifying the binder can be shortened.

  In the present invention, the temperature of the high-temperature and high-humidity gas may be adjusted so as to increase with time and passed through the molding die.

  In this way, since the temperature of the high-temperature and high-humidity gas is low at the initial stage of passing the high-temperature and high-humidity gas through the mold, the time until the temperature of the high-temperature and high-humidity gas falls below the dew point temperature to generate condensed water is reduced. At the end of passing the high-temperature high-humidity gas through the mold, the temperature of the high-temperature high-humidity gas is high, so the efficiency of evaporating the condensed water is high, and the time for drying and solidifying the binder is reduced. It is something that can be done.

  In the present invention, the high-temperature high-humidity gas may be passed through the mold by forcibly discharging the high-temperature high-humidity gas outside the mold while blowing the high-temperature high-humidity gas into the mold.

  Thus, by forcibly discharging the high-temperature and high-humidity gas blown into the mold, the efficiency of passing the high-temperature and high-humidity gas through the mold can be increased.

  In the present invention, saturated water vapor may be passed through the mold before the high-temperature and high-humidity gas is passed through the mold.

  By passing saturated water vapor through a mold in advance, condensed water can be generated from this water vapor, and the binder of the binder-coated refractory can be moistened to ensure that the adhesive action is exerted. It is.

  In the present invention, after passing a high-temperature high-humidity gas through the mold, a gas having a lower water vapor concentration than the high-temperature high-humidity gas may be passed through the mold to dry and solidify the binder.

  Thus, by passing a dry gas having a lower water vapor concentration than a high-temperature, high-humidity gas through a mold, moisture contained in the binder of the binder-coated refractory can be efficiently evaporated. The time for drying and solidifying can be further shortened.

  Further, in the present invention, after filling the mold with the binder-coated refractory, the inside of the mold may be decompressed, and then the high-temperature and high-humidity gas may be passed through the mold.

  By passing the high-temperature and high-humidity gas through the mold in such a reduced pressure state, the high-temperature and high-humidity gas is distributed throughout the mold, and the binder-coated refractory in the mold is uniformly heated. A high-humidity gas can be made to act, and a condensate of high-temperature high-humidity gas can be uniformly supplied to the binder-coated refractory to form a mold having a uniform strength.

According to the present invention, the high-temperature and high-humidity gas passed through the mold has a temperature of 50 to 500 ° C. and a water vapor concentration of 10 to 60 %, so the water content of the high-temperature and high-humidity gas wets the binder. It is sufficient to give a sticking action in a state, and is much less than water vapor conventionally used, and it is not rare that excessive condensed water is generated in the mold. The time for evaporating the binder and drying and solidifying the binder can be shortened, the molding time of the mold can be shortened, and a large amount of excess condensed water is generated in the mold in this way. Therefore, the binder of the binder-coated refractory is not washed away with condensed water, and a mold having uniform strength can be produced without the binder being unevenly distributed.

An example of embodiment of this invention is shown, (a) (b) is a schematic sectional drawing in each process, respectively. The apparatus which prepares the high temperature, high humidity gas used for the same as the above is shown, (a) thru | or (d) are schematic. It is a schematic sectional drawing which shows an example of other embodiment of this invention.

  Embodiments of the present invention will be described below.

  The binder-coated refractory is formed by coating the surface of the refractory aggregate particles with a coating layer containing a binder. The refractory aggregate is not particularly limited, and examples thereof include dredged sand, mountain sand, alumina sand, olivine sand, chromite sand, zircon sand, mullite sand, reclaimed sand, and other artificial sand. These may be used alone or in combination of a plurality of types.

  In the present invention, a binder-coated refractory formed by coating a refractory aggregate with a coating layer using a binder selected from sugars, water-soluble inorganic compounds, and water-soluble thermoplastic resins is used. . Saccharides swell or dissolve in water and become sticky to become sticky, and water-soluble inorganic compounds and water-soluble thermoplastic resins dissolve in water and become sticky and show sticky These binders are water-adhesive binders that generate an adhesive action when they are in a wet state upon absorbing moisture.

  Here, monosaccharides, oligosaccharides, and polysaccharides can be used as the saccharides, and one type selected from various monosaccharides, oligosaccharides, and polysaccharides can be used alone. You can also select and use them together.

  Although it does not specifically limit as monosaccharide used in this invention, Glucose (glucose), fructose (fructose), galactose, etc. can be mentioned.

  Examples of oligosaccharides include disaccharides such as maltose (malt sugar), sucrose (sucrose), lactose (lactose), and cellobiose.

  Furthermore, as polysaccharides, there are starch sugar, dextrin, xanthan gum, curdlan, pullulan, cycloamylose, chitin, chitosan, cellulose, starch, etc., one of these is selected or used in combination of two or more. be able to. Examples of starch include raw starch and processed starch. Specifically, raw starch such as potato starch, corn starch, high amylose, sweet potato starch, tapioca starch, sago starch, rice starch, amaranth starch, and these modified starches (roasted dextrin, enzyme-modified dextrin, acid-treated starch, Oxidized starch), dialdehyde starch, etherified starch (carboxymethyl starch, hydroxyalkyl starch, cationic starch, methylolated starch, etc.), esterified starch (acetic acid starch, phosphate starch, succinate starch, octenyl succinate starch, Acid starch, higher fatty acid esterified starch, etc.), cross-linked starch, kraft starch, and wet heat-treated starch. Among these, low-viscosity starches such as roasted dextrin, cyclodextrin, enzyme-modified dextrin, acid-treated starch, oxidized starch, and crosslinked starch are preferred. Furthermore, saccharide-containing plants such as wheat, rice, potato, corn, tapioca, sweet potato, sago, amaranth and the like can be used. In addition, sugars that are commercially available for food use, such as white crude, medium crude, granulated sugar, invert sugar, super white sugar, medium white sugar, tri-warm sugar, and the like can also be used. Furthermore, phenol-modified saccharides obtained by reacting saccharides with phenols can also be used.

  The coating layer may contain carboxylic acid as a curing agent for saccharides, particularly polysaccharides. The carboxylic acid is not particularly limited, and examples thereof include polyvalent carboxylic acids such as oxalic acid, maleic acid, succinic acid, citric acid, butanetetradicarboxylic acid, and methyl vinyl ether-maleic anhydride copolymer. it can. The content of the carboxylic acid in the coating layer is preferably in a range where the blending amount of the carboxylic acid with respect to the saccharide is 0.1 to 10 parts by mass of the carboxylic acid with respect to 100 parts by mass of the saccharide. Carboxylic acid is preferably mixed with saccharide in a state of being dissolved in water in advance because the effect as a curing agent is exhibited highly.

  The water-soluble inorganic compound is not particularly limited, but water glass, sodium chloride, sodium phosphate, sodium carbonate, sodium vanadate, sodium borate, sodium aluminum oxide, potassium chloride, potassium carbonate, Sulfuric acid compounds can be used. These can be used alone or in combination of any plural types.

Additional water glass is a mixture of silicic anhydride (SiO ₂₎ and sodium oxide _(Na 2 O), also called sodium silicate, represented by the general formula _{Na 2 O · nSiO 2 · xH} 2 O shown in JIS K1408, A powdery, liquid or crystalline material can be used. Further, potassium silicate (K ₂ O · nSiO ₂ ) can also be used.

Water glass is extremely soluble in water and solidifies by drying. For this reason, by using water glass as a binder, it is possible to produce a mold that easily disintegrates with water. Moreover, since water glass can be obtained at low cost, a mold can be manufactured at low cost. Furthermore, since Na ₂ SiO ₃ has a relatively high melting point of 1088 ° C., a mold having high heat resistance can be produced.

  The above-mentioned sodium chloride (NaCl) is edible, so-called salt, is harmless to the human body, is inexpensive, and is easy to use. And since it melt | dissolves easily in water, the casting_mold | template which disintegrates easily with water can be manufactured by using sodium chloride as a binder. In particular, the solubility of sodium chloride in water in the temperature range of 0 to 100 ° C. is 35.7 to 39.1 g with respect to 100 g of water, and the change due to the water temperature is small, so that workability is good. Further, since NaCl has a relatively high melting point of 800.4 ° C., a mold having high heat resistance can be manufactured.

Examples of the sodium phosphate include monosodium phosphate hydrate (NaH ₂ PO ₄ xH ₂ O), disodium phosphate hydrate (Na ₂ HPO ₄ xH ₂ O), and trisodium phosphate hydrate. (Na ₃ PO ₄ .xH ₂ O) or the like can be used. Trisodium phosphate hydrate is soluble in water so that the amount dissolved in 100 g of water is 1.5 g (0 ° C.), and disodium phosphate hydrate has a melting point of 1340. As at ° C, the melting point of sodium phosphate is relatively high. For this reason, a mold that easily disintegrates with water and has high heat resistance can be produced.

The above-mentioned sodium carbonate (K ₂ CO ₃ ) is easily dissolved in water and is inexpensive so that the amount dissolved in 100 g of water is 7.1 g (0 ° C.). The melting point is relatively high at 851 ° C. For this reason, a mold that easily disintegrates with water and has high heat resistance can be produced.

The above sodium vanadate (Na ₃ VO ₄ ) is soluble in water and has a relatively high melting point of 866 ° C. For this reason, a mold that easily disintegrates with water and has high heat resistance can be produced.

The sodium borate (Na ₂ B ₄ O ₇ xH ₂ O) is easily dissolved in water and inexpensive, so that the amount dissolved in 100 g of water is 1.6 g (10 ° C.). The melting point is relatively high at 741 ° C. For this reason, a mold that easily disintegrates with water and has high heat resistance can be produced.

The sodium aluminum oxide (NaAlO ₂ ) is soluble in water and has a high melting point of 1700 ° C. or higher. For this reason, a mold that easily disintegrates with water and has high heat resistance can be produced.

  The potassium chloride (KCl) is easily dissolved in water and is inexpensive so that the amount dissolved in 100 g of water is 28.1 g (0 ° C.). The melting point is relatively high at 776 ° C. For this reason, a mold that easily disintegrates with water and has high heat resistance can be produced.

The potassium carbonate (K ₂ CO ₃ ) is easily dissolved in water such that the amount dissolved in 100 g of water is 129.4 g (0 ° C.), and has a relatively high melting point of 891 ° C. For this reason, a mold that easily disintegrates with water and has high heat resistance can be produced.

The sulfuric acid compound is not particularly limited, but includes MgSO ₄ , Na ₂ SO ₄ .xH ₂ O, Al ₂ (SO ₄ ) ₃ .xH ₂ O, K ₂ SO ₄ , NiSO _4. xH ₂ O, ZnSO ₄ .xH ₂ O, MnSO ₄ .xH ₂ O, K ₂ Mg (SO ₄ ) ₂ .xH ₂ O, and the like can be given.

Sulfuric acid compounds are easily dissolved in water and inexpensive. For example, the amount dissolved in 100 g of water is 26.9 g (0 ° C.) for magnesium sulfate (MgSO ₄ ), 19.4 g (20 ° C.) for sodium sulfate decahydrate (Na ₂ SO ₄ .10H ₂ O), Aluminum sulfate 12 hydrate (Al ₂ (SO ₄ ) ₃ · 12H ₂ O) is 36.2 g (20 ° C.), potassium sulfate (K ₂ SO ₄ ) is 10.3 g (0 ° C.), nickel sulfate · 7 Hydrate (NiSO ₄ · 7H ₂ O) is 39.7 g (20 ° C.), and manganese sulfate · pentahydrate (MnSO ₄ · 5H ₂ O) is 75.3 g (25 ° C.). For this reason, by using a sulfuric acid compound as a binder, a mold that easily disintegrates with water can be produced at low cost. The melting point of the sulfate compound is, for example, 1185 ° C. for magnesium sulfate (MgSO ₄ ), 884 ° C. for sodium sulfate decahydrate (Na ₂ SO ₄ .10H ₂ O), and aluminum sulfate dodecahydrate (Al ₂ ( SO ₄ ) ₃ · 12H ₂ O) is 770 ° C., potassium sulfate (K ₂ SO ₄ ) is 1067 ° C., nickel sulfate heptahydrate (NiSO ₄ · 7H ₂ O) is 840 ° C., zinc sulfate · 7 hydrate The product (ZnSO ₄ .7H ₂ O) is 740 ° C., manganese sulfate pentahydrate (MnSO ₄ .5H ₂ O) is 850 ° C., and potassium magnesium sulfate (K ₂ Mg (SO ₄ ) ₂ .6H ₂ O) is Since it is relatively high at 927 ° C., a mold having high heat resistance can be produced.

  As the water-soluble inorganic compound, any one of the above-listed compounds can be selected and used alone, or any plurality of these can be used in combination.

  Further, the water-soluble thermoplastic resin is not particularly limited, but polyacrylamide, polyacrylic acid, polymethacrylic acid, polyitaconic acid, polyvinyl alcohol, polyethylene oxide, polyvinyl pyrrolidone, polyvinyl methyl ether, methyl cellulose, methoxy And nylon. Any one of these water-soluble thermoplastic resins can be selected and used alone, or a plurality of water-soluble thermoplastic resins can be used in combination.

  Each of the saccharide, the water-soluble inorganic compound, and the water-soluble thermoplastic resin may be used alone or in any combination. For example, saccharides and water-soluble inorganic compounds, saccharides and water-soluble thermoplastic resins, water-soluble inorganic compounds and water-soluble thermoplastic resins, and combinations of saccharides, water-soluble inorganic compounds and water-soluble thermoplastic resins can be used in combination. Thus, when using 2 or more types together, the combination ratio of combined use can be set arbitrarily.

  Furthermore, in order to improve the fluidity of the binder-coated refractory, a lubricant may be contained in the coating layer. Examples of lubricants include aliphatic hydrocarbon lubricants such as paraffin wax and carnauba wax, higher aliphatic alcohols, aliphatic amide lubricants such as ethylenebisstearic acid amide and stearic acid amide, metal soap lubricants, and fatty acid ester lubricants. A composite lubricant or the like can be used, and among them, a metal soap-based lubricant is preferable. As the metal soap-based lubricant, calcium stearate, barium stearate, zinc stearate, aluminum stearate, magnesium stearate, or a combination of these can be used.

  And by blending and mixing saccharides, water-soluble inorganic compound, water-adhesive binder selected from water-soluble thermoplastic resin, and carboxylic acid, lubricant, etc. if necessary, into particles of refractory aggregate, The binder-coated refractory according to the present invention can be obtained by covering the surface of the refractory aggregate with a coating layer containing a binder.

  The amount of the coating layer coated on the refractory aggregate differs depending on the components and applications, and cannot be specified unconditionally. However, the binder is 0.5 to 6.0 parts by mass with respect to 100 parts by mass of the refractory aggregate, lubricant Is generally preferred to be in the range of 0.02 to 0.15 parts by mass in solid content. Examples of methods for coating the surface of the refractory aggregate with a coating layer include a hot coat method, a cold coat method, a semi-hot coat method, and a powder solvent method.

  In the hot coating method, a solid binder is added to and mixed with a refractory aggregate heated to 110 to 180 ° C., and the solid binder is melted by heating with the refractory aggregate. In this method, the surface of the refractory aggregate is wetted and coated, and then cooled with the mixture kept, thereby obtaining a granular and free-flowing binder-coated refractory. Alternatively, a method for obtaining a binder-coated refractory by mixing a refractory aggregate heated to 110 to 180 ° C. with a binder that is dissolved or dispersed in a solvent such as water and coating the mixture to volatilize the solvent. It is.

  In the cold coating method, the binder is dispersed or dissolved in a solvent such as water or methanol to form a liquid, which is added to and mixed with the refractory aggregate particles, and the solvent is volatilized to coat the binder. It is a method of obtaining a refractory.

  In the semi-hot coating method, the binder dispersed or dissolved in the above solvent is added to and mixed with the particles of the refractory aggregate heated to 50 to 90 ° C., and the solvent is volatilized. Is the way to get.

  In the powder solvent method, a solid binder is pulverized, this pulverized binder is added to the refractory aggregate particles, and a solvent such as water or methanol is added and mixed to volatilize the solvent. To obtain a binder-coated refractory.

  In any of the above methods, the surface of the refractory aggregate can be coated with a solid coating layer at room temperature (30 ° C.) to obtain a binder-coated refractory having a granular and smooth fluidity. In view of workability, the hot coating method is preferable. In addition, when mixing the binder with the refractory aggregate as described above, various coupling agents such as a curing agent and a silane coupling agent for making the refractory aggregate and the binder compatible with each other, Moreover, carbonaceous materials, such as graphite, can also be mix | blended.

  In manufacturing a mold using the binder-coated refractory prepared as described above, the present invention fills the mold with the binder-coated refractory, and then places the mold in a high-temperature and high-humidity gas. It is done by passing through.

  That is, as shown in FIG. 1A, the injection port 4 is provided on the upper surface of the mold 1 formed by providing the cavity 3 therein, and the lower surface of the mold 1 is closed with a net 5 such as a metal mesh. A discharge port 6 is provided. This type can be divided vertically or horizontally. The binder-coated refractory 2 is stored in a hopper 7, and an air supply pipe 9 with a cock 8 is connected to the hopper 7. Then, after the nozzle port 7 a at the lower end of the hopper 7 is matched with the injection port 4 of the mold 1, the cock 8 is switched from closed to open, so that air is blown into the hopper 7 to pressurize the hopper 7. The binder-coated refractory 2 is blown into the mold 1 to fill the cavity 3 of the mold 1 with the binder-coated refractory 2. Since the discharge port 6 is blocked by the net 5, the binder coated refractory 2 does not leak from the discharge port 6. When a plurality of the inlets 4 and the outlets 6 are provided in the mold 1 as in the embodiment of FIG. 1, the binder-coated refractory 2 is inserted from one or a plurality of the inlets 4. That's fine.

  Here, since the coating layer of the binder-coated refractory 2 is made of a solid binder, the binder-coated refractory 2 has no adhesiveness on the surface and has good fluidity. . Therefore, when the binder-coated refractory 2 is filled into the mold 1 as described above, the binder-coated refractory 2 can be smoothly poured into the cavity 3 of the mold 1, and the mold 1 has a good filling property. It is possible to fill the binder-coated refractory 2 with a filler, and to prevent the occurrence of poor filling.

  After filling the mold 1 with the binder-coated refractory 2 as described above, the hopper 7 is removed from the inlet 4 of the mold 1 and an air supply pipe 10 is connected to each inlet 4 as shown in FIG. Connect. A high temperature and high humidity gas is supplied to the air supply pipe 10.

The high-temperature and high-humidity gas used in the present invention is a mixed gas of water vapor and a gas other than water vapor. As the gas other than water vapor, any gas such as nitrogen gas can be used in addition to air, but air is preferably used from the viewpoint of cost and ease of use. In the present invention, the high-temperature and high-humidity gas has a temperature in the range of 50 to 500 ° C. and a water vapor concentration in the range of 10 to 90%. This water vapor concentration refers to the proportion of the volume of water vapor in the high-temperature and high-humidity gas (approximate water vapor partial pressure / total pressure). For example, water vapor concentration (%) =
[Volume of water vapor / (volume of water vapor + volume of gas other than water vapor)] × 100
It can be obtained from the following formula.

  Here, such a high-temperature, high-humidity gas can be prepared by mixing water vapor and a gas such as air. By adjusting the mixing ratio of water vapor and gas such as air, the water vapor concentration can be easily set in the range of 10 to 90%. The temperature of the high-temperature and high-humidity gas is easily set in the range of 50 to 500 ° C. by heating after mixing a gas such as water vapor and air, or by heating the gas to a predetermined temperature in advance. be able to.

  FIG. 2 (a) shows an example of an apparatus for preparing a high-temperature and high-humidity gas, in which a water vapor generating device 15 and a gas supply device 16 formed by a boiler or the like are connected to a mixer 17 with a heater. The gas supply device 16 is formed by a blower, a compressor, or the like when air in the atmosphere is used as the gas, and is formed by a gas cylinder or the like when nitrogen gas or the like is used as the gas. Valves 18 and 19 are provided between the mixer 17 and the steam generator 15 and the gas supply device 16.

  In this apparatus, water vapor is supplied from the water vapor generating device 15 and gas such as air is supplied from the gas supply device 16 to the mixer 17 and heated to a predetermined temperature with a heater while mixing in the mixer 17. High temperature and high humidity gas can be prepared. At this time, the water vapor concentration of the high-temperature and high-humidity gas can be arbitrarily adjusted by adjusting the ratio of the water vapor sent from the water vapor generating device 15 and the gas supplied from the gas supply device 16 by operating the valves 18 and 19. . The high-temperature and high-humidity gas thus prepared is supplied to the air supply pipe 10 described above.

  Here, saturated water vapor can be used as it is, but superheated water vapor can also be used. Superheated steam is steam obtained by heating saturated steam to a temperature equal to or higher than the boiling point of water. The superheated steam may be atmospheric superheated steam obtained by heating the saturated steam while expanding it at a constant pressure without increasing the pressure, or pressurized superheated steam obtained by heating without expanding the saturated steam. May be. The temperature of the superheated steam is not particularly limited, and may be set to a temperature as required between about 100 to 900 ° C.

  In the example of FIG. 2B, the superheater 20 is connected to the steam generator 15, and the steam generated by the steam generator 15 is heated through the superheater 20 to be heated to 100 ° C. or higher. After that, it is supplied to the mixer 17 through the valve 18. 2A and 2B, when it is not necessary to adjust the temperature by heating a mixed gas of water vapor and air or the like, the mixer 17 is unnecessary, and the water vapor and the gas are put in the pipe. It is possible to prepare a mixed gas by mixing with.

  When preparing a high-temperature and high-humidity gas as a high-temperature and high-humidity gas, it is preferable to mix superheated steam at 100 ° C. or higher and gas other than water vapor such as high-temperature air heated to 100 ° C. or higher. FIG. 2 (c) shows an example of such a device, in which a superheater 20 is connected to the water vapor generating device 15 and a heater 21 having a heater or the like is connected to the gas supply device 16.

  The steam generated by the steam generator 15 is passed through the superheater 20 to be superheated steam having a predetermined temperature of 100 ° C. or higher, and this superheated steam is supplied to the mixer 17 through the valve 18. Further, a gas such as air is passed from the gas supply device 16 through the heater 21 to be a high-temperature gas having a predetermined temperature of 100 ° C. or higher, and this high-temperature gas is supplied to the mixer 17 through the valve 19 and mixed gas of superheated steam and high-temperature gas. As a high temperature and high humidity gas can be prepared. The mixer 17 has a built-in heater, which can further heat the high-temperature and high-humidity gas. However, when it is not necessary to heat the mixed gas of superheated steam and high-temperature gas, the mixer 17 is unnecessary. Yes, superheated steam and hot gas are mixed in the pipe to become a mixed gas.

  The high temperature and high humidity gas can also be prepared by vaporizing water in a gas other than water vapor such as air. For example, as shown in FIG. 2 (d), a gas such as air and water are supplied to the heater 23, and the water is heated and vaporized in the heater 23. Can be prepared. At this time, as shown by the solid line in FIG. 2 (d), water may be sprayed or dripped onto the gas so that the water drops are mixed with the gas and sent to the heater 23. As indicated by a broken line in FIG. 6, water may be directly supplied to the heater 23 separately from the gas.

  As shown in FIG. 1B, the air supply pipe 10 is connected to each inlet 4 of the mold 1 and the cock 11 is opened, so that the high-temperature and high-humidity gas prepared as described above passes through the air supply pipe 10. It is blown into the cavity 3 of the mold 1. The high-temperature and high-humidity gas blown into the mold 1 passes through the particles of the binder-coated refractory 2 filled in the cavity 3 and is then discharged from the discharge port 6.

  When the high temperature and high humidity gas is passed through the mold 1 in this way, the high temperature and high humidity gas is brought into contact with the surface of the binder-coated refractory 2 in the initial step of passing the high temperature and high humidity gas. The temperature of the humid gas is lowered to the dew point temperature or less, the water vapor in the high temperature and high humidity gas is condensed, and condensed water is generated on the surface of the binder-coated refractory 2. Since the water-adhesive binder comprising the saccharide, water-soluble inorganic compound, and water-soluble thermoplastic resin in the coating layer on the surface of the binder-coated refractory 2 is solid, the binder-coated refractory remains solid. However, when condensed water is supplied to the surface of the binder-coated refractory 2 as described above, the solid binder becomes a wet paste due to the replenishment of moisture. Thus, the particles of the binder-coated refractory 2 can be bonded to each other by the adhesiveness of the binder.

  In this way, the water-adhesive binder of the binder-coated refractory 2 can be gelatinized with condensed water of high-temperature and high-humidity gas, and the binder-coated refractory can be caking with this binder. Then, the binder-coated refractory 2 is heated with a high-temperature and high-humidity gas that is continuously passed through the mold 1. Since the water vapor in the high-temperature and high-humidity gas has a high latent heat, the temperature of the binder-coated refractory 2 rapidly rises above the dew point temperature of the high-temperature and high-humidity gas due to the latent heat transferred when the water vapor condenses. . Thus, the time during which the binder-coated refractory 2 is heated to the dew point temperature or higher is the temperature and water vapor concentration of the high-temperature and high-humidity gas, the flow rate of blowing into the mold 1, and the binder-coated material in the mold 1. Although it varies depending on the filling amount of the refractory 2, it is usually a short time of about 2 to 30 seconds. When the binder-coated refractory 2 is heated to the dew point temperature or higher in this way, moisture contained in the binder on the surface of the binder-coated refractory 2 evaporates, and the binder can be dried. The evaporated water is exhausted from the discharge port 6 together with the high-temperature and high-humidity gas that has passed through the mold 1.

  As described above, by passing the high-temperature and high-humidity gas through the mold 1, the water vapor in the high-temperature and high-humidity gas is condensed to supply water to the binder of the binder-coated refractory 2, and the binder The coated refractory 2 is caulked by the adhesive action of the binder, and then heated with a high-temperature and high-humidity gas that passes through the mold 1 to evaporate the moisture of the binder, and the binder is dried and solidified. It can be made to. And the bond of the refractory aggregate due to the adhesive action of the water-adhesive binder becomes strong when the binder solidifies, and a high-strength mold can be obtained. After the molding is completed in this way, the mold can be taken out by opening the mold 1.

  Here, the high-temperature and high-humidity gas passed through the mold 1 has a temperature of 50 to 500 ° C. and a water vapor concentration of 10 to 90%, and contains a lower amount of water than saturated water vapor. For this reason, the high-temperature and high-humidity gas is cooled by the binder-coated refractory 2 in the mold 1 and the temperature is lowered, and the amount of the condensed water generated when the temperature of the high-temperature and high-humidity gas falls below the dew point is excessive. It does not increase, and the occurrence of excess condensed water in the mold 1 is reduced. The amount of the binder coated on the binder coated refractory 2 is only about 0.5 to 6% by mass of the refractory aggregate as described above. The amount of water necessary for the treatment is about 0.1 to 3 times that of the binder. Therefore, the amount of condensed water generated from the high-temperature and high-humidity gas can sufficiently exert the adhesive action on the binder of the binder-coated refractory 2.

  And in this invention, since the quantity of the condensed water produced | generated from a high-temperature high-humidity gas in the shaping | molding die 1 can be suppressed in this way, in order to provide a sticking action to the binder of the binder coated refractory 2, When the moisture contained in the binder is evaporated by heating with high-temperature and high-humidity gas that is continuously passed through the mold 1 after replenishing moisture, the time required for evaporation becomes unnecessary. Can be shortened, and the drying and solidifying time of the binder can be shortened.

  In addition, since a large amount of condensed water is not generated in the mold 1 in this way, the binder on the surface of the binder-coated refractory 2 is dissolved in the condensed water and flowed. It can be prevented. Therefore, the binder does not become unevenly distributed in the mold due to the flow of the binder, and a mold having a uniform strength can be manufactured.

  As described above, the high-temperature and high-humidity gas needs to have a water vapor concentration of 90% or less so that excess condensed water is not generated in the mold 1. However, if the water vapor concentration is too low, the generation of condensed water is too small, and there is a risk that the adhesive of the binder-coated refractory 2 cannot be sufficiently imparted with a sticking action, and the dew point temperature is low. The water vapor concentration needs to be 10% or more.

  In the present invention, the water vapor concentration of the high-temperature and high-humidity gas is set between 10% and 90% as described above, but the water vapor concentration of 60 is surely prevented from generating excessive condensed water in the mold 1. It is desirable that the water vapor concentration is 30% or more in order to sufficiently generate condensed water and to ensure the adhesive action of the binder of the binder-coated refractory 2 sufficiently. . Therefore, in the present invention, the water vapor concentration of the high temperature and high humidity gas is more preferably in the range of 30 to 60%.

  If the temperature of the high-temperature and high-humidity gas is too high, the high-temperature and high-humidity gas may not drop below the dew point in the mold 1, and there is a possibility that sufficient condensed water cannot be generated in the mold 1. Therefore, the temperature of the high temperature and high humidity gas needs to be 500 ° C. or less. On the other hand, if the temperature of the high-temperature and high-humidity gas is too low, the efficiency of heating the binder-coated refractory 2 with the high-temperature and high-humidity gas and evaporating the condensed water deteriorates, and the binder of the binder-coated refractory 2 is deteriorated. Since it takes a long time to dry and solidify, the temperature of the high-temperature and high-humidity gas needs to be 50 ° C. or higher.

  Here, the temperature and water vapor concentration of the high-temperature and high-humidity gas may be adjusted within the range of the temperature of 50 to 500 ° C. and the water vapor concentration of 10 to 90% according to the atmospheric temperature such as summer and winter. For example, when the outside air temperature or the temperature of the binder-coated refractory 2 is low, such as in winter, a high temperature and high humidity gas having a relatively low temperature and water vapor concentration of about 50 ° C. and a water vapor concentration of about 10% can be used. The molding can be performed sufficiently. In this case, the molding can be performed with a high-temperature and high-humidity gas having a low energy cost.

  Here, in the present invention, the high temperature and high humidity gas is cooled to below the dew point temperature by the binder coated refractory 2 in the mold 1 at the initial stage of passing the high temperature and high humidity gas through the mold 1 as described above. Since the condensed water is generated from the water vapor in the high-temperature and high-humidity gas, the binder-coated refractory 2 filled in the mold 1 has a temperature lower than the dew point of the high-temperature and high-humidity gas. It is necessary to be. However, if the temperature of the binder-coated refractory 2 is low, the high-temperature and high-humidity gas is excessively cooled, and the temperature is greatly lowered from the dew point, so that excessive condensed water may be generated from the high-temperature and high-humidity gas. In addition, the time required for evaporating the moisture absorbed in the binder of the binder-coated refractory 2 and drying the binder becomes long.

  For this reason, the binder-coated refractory 2 is preheated in the temperature range below the dew point of the high-temperature and high-humidity gas, and the binder-coated refractory 2 thus preheated is blown into the mold 1. It should be filled. Since the water vapor concentration of the high temperature and high humidity gas used in the present invention is 10 to 90%, the dew point temperature of this high temperature and high humidity gas is about 45 to 97 ° C. The binder-coated refractory 2 is preferably preheated to a temperature lower than this dew point temperature by 5 to 30 ° C. If the preheating temperature of the binder-coated refractory 2 is only 5 ° C. lower than the dew point temperature, the temperature drop of the high-temperature and high-humidity gas is low, and the generation of condensed water may be insufficient. Conversely, when the preheating temperature of the binder-coated refractory 2 is lower by 30 ° C. or more than the dew point temperature, the high-temperature and high-humidity gas greatly decreases in temperature as described above, and excessive condensed water is generated, and the drying time becomes longer. .

  Further, water vapor blown into the cavity 3 in the mold 1 passes through the inside away from the mold surface of the mold 1 (inner surface of the cavity 3) and is discharged from the discharge port 4, or the mold of the mold 1. Some of them pass near the surface and are discharged from the discharge port 4. And although the shaping | molding die 1 is normally used for shaping | molding in the heated state, the temperature of the shaping | molding die 1 does not act on the high-temperature, high-humidity gas discharged | emitted through the inside away from the type | mold surface of the shaping | molding die 1. As a result, the temperature decreases and condensed water is generated. However, since the temperature of the mold 1 acts on the high-temperature and high-humidity gas that passes through the vicinity of the mold surface of the mold 1, if the mold temperature of the mold 1 is too high, the high-temperature and high-humidity gas is generated. Even if it contacts the binder coated refractory 2, the temperature of the high temperature and high humidity gas does not decrease so much due to the high temperature of the mold 1 and is discharged from the mold 1 without generating condensed water. It will be. Therefore, it is difficult for condensed water to be generated from the high-temperature and high-humidity gas passing near the surface of the high-temperature mold 1, and even if condensed water is generated, it will evaporate immediately. A sufficient amount of water is not supplied to the binder-coated refractory 2 in the portion in contact with the mold surface of the mold 1 until the binder becomes wet, and the adhesive does not have sufficient adhesiveness. The binder will dry and solidify. As a result, the binder-coated refractory 2 in the portion in contact with the mold surface of the mold 1 cannot be sufficiently bonded with the binder, and the particles of the binder-coated refractory 2 having insufficient bonding force are formed in the mold. There is a risk that a phenomenon of tattering that peels off from the surface of the substrate will occur.

  Therefore, in the present invention, it is preferable that the mold temperature of the mold 1 is set to a temperature range lower than the dew point temperature of the high-temperature and high-humidity gas passed through the mold 1 and heated. By setting the mold temperature of the mold 1 to a temperature lower than the dew point temperature of the high-temperature and high-humidity gas in this way, the high-temperature and high-humidity gas discharged through the vicinity of the surface of the mold 1 is transferred to the high temperature of the mold 1. In this way, condensed water is easily generated from the high-temperature and high-humidity gas even in the vicinity of the mold surface of the mold 1. For this reason, the binder-coated refractory 2 in the portion in contact with the mold surface of the mold 1 can be sufficiently supplied with moisture so that the binder becomes wet and exhibits an adhesive action. The binder-coated refractory 2 in the portion in contact with the mold surface of the mold 1 can be sufficiently bonded with this binder. Therefore, the binder-coated refractory 2 can be firmly bonded to the surface layer of the mold so that the surface strength can be increased, and the occurrence of a battering phenomenon on the surface of the mold can be prevented. Is.

  Since the dew point temperature of the high temperature and high humidity gas used in the present invention is about 45 to 90 ° C. as described above, the mold temperature of the mold 1 is heated to a lower temperature in the range of 5 to 30 ° C. than the dew point temperature. It is preferable to use it. If the mold temperature of the mold 1 is only 5 ° C. lower than the dew point temperature, the condensed water is not sufficiently generated from the high-temperature and high-humidity gas, and there is a possibility that the batter phenomenon cannot be prevented. Conversely, when the mold temperature of the mold 1 is lower by 30 ° C. or more from the dew point temperature, excessive condensed water is generated from the high-temperature and high-humidity gas, and the drying time may be prolonged. Here, the mold temperature of the mold 1 refers to the surface temperature in the cavity 3 where the binder coated refractory 2 is filled to mold the mold.

  In the above embodiment, the high-temperature and high-humidity gas that is passed through the mold 1 is the same in temperature and water vapor concentration from the beginning to the end of the molding process. The high-temperature and high-humidity gas may be passed through the mold 1 while changing the water vapor concentration with time so that the water vapor concentration is high and the water vapor concentration is low at the end stage. Thus, in the initial stage of passing the high-temperature and high-humidity gas through the mold 1, if the water vapor concentration of the high-temperature and high-humidity gas is high, the condensed water for making the binder of the binder-coated refractory 2 wet. Can be easily generated from high-temperature and high-humidity gas, and when the water vapor concentration of high-temperature and high-humidity gas is low at the final stage of passing the high-temperature and high-humidity gas through the mold 1, the binder of the binder coated refractory 2 The efficiency of drying the moisture contained in is increased.

  In order to change the water vapor concentration of the high-temperature and high-humidity gas so as to decrease with time in this way, for example, by adjusting the opening amounts of the valves 18 and 19 in FIGS. This can be done easily by changing the mixing ratio with the gas. Further, when the water vapor concentration of the high-temperature and high-humidity gas is changed with time, the water vapor concentration may be changed so as to decrease continuously, or the water vapor concentration may be changed so as to decrease stepwise.

  Alternatively, the temperature of the high-temperature and high-humidity gas may be changed so as to increase with time so that the temperature is low at the initial point of passage through the mold 1 and high at the final point. Thus, when the temperature of the high-temperature and high-humidity gas is low at the initial stage, the temperature of the high-temperature and high-humidity gas is likely to fall below the dew point temperature, and condensed water is easily generated from the high-temperature and high-humidity gas. In addition, when the temperature of the high-temperature and high-humidity gas is high at the final stage, the efficiency of drying the moisture contained in the binder increases.

  Alternatively, saturated steam may be passed through the mold 1 before passing the high-temperature and high-humidity gas through the mold 1 filled with the binder-coated refractory 2 as described above. Saturated water vapor generates condensed water with a slight temperature drop, so that moisture can be reliably supplied to the binder-coated refractory 2 in the mold 1 and an adhesive action can be produced on the binder. is there. Since the saturated steam is only passed through the mold 1 for the purpose of supplying moisture, the time for passing the saturated steam through the mold 1 may be short.

  Further, after passing the high-temperature and high-humidity gas through the mold 1 as described above, the supply of the high-temperature and high-humidity gas is stopped, and the dried gas having a lower water vapor concentration than the high-temperature and high-humidity gas is passed through the mold 1. It may be. The dry gas may be any gas other than water vapor, and air or other nitrogen gas can be used. Since this gas is a dry gas whose water vapor concentration is lower than that of a high-temperature and high-humidity gas, the efficiency of evaporating the water content of the binder of the binder-coated refractory 2 is high, and the time for drying and solidifying the binder is shortened. Is something that can be done.

  The dried gas having a water vapor concentration lower than that of the high-temperature and high-humidity gas may be a heated gas or a gas at a normal temperature (for example, 25 ° C.) such as a working environment temperature. When it is a heated gas, the efficiency of evaporating the water content of the binder of the binder-coated refractory 2 is high, and the time for drying and solidifying the binder can be further shortened. The temperature of the heated gas is not particularly limited, and may be 100 ° C. or higher and not higher than the temperature at which the binder is not decomposed. In addition, when the gas is normal temperature, the moisture of the binder of the binder coated refractory 2 is evaporated, and at the same time, the temperature of the mold molded in the mold 1 is rapidly lowered to a temperature at which demolding is possible. The time for taking out can be shortened.

  In the embodiment of FIG. 3, a suction pipe 12 is connected to the discharge port 6 of the mold 1, and a vacuum pump or the like is connected to the suction pipe 12. Then, the high-temperature and high-humidity gas is blown into the mold 1 from the air supply pipe 10 as described above while sucking the mold 1 with the suction pipe 12. By blowing the high temperature and high humidity gas while sucking the inside of the mold 1 in this way, the high temperature and high humidity gas is forced after passing between the particles of the binder coated refractory 2 filled in the mold 1. The high-temperature and high-humidity gas is not retained in the mold 1. For this reason, the efficiency of heating with high-temperature and high-humidity gas is increased, the time for drying and solidifying the binder of the binder-coated refractory 2 can be shortened, and the mold can be manufactured in a shorter time. It will be.

  In addition, after filling the mold 1 with the binder-coated refractory 2, the molding mold 1 filled with the binder-coated refractory 2 is decompressed when the mold 1 is molded with high-temperature and high-humidity gas. After that, a high-temperature and high-humidity gas may be passed through the mold 1. By passing the high-temperature and high-humidity gas through the mold 1 in a reduced pressure state in this way, the high-temperature and high-humidity gas spreads throughout the cavity 3 of the mold 1, and the binder-coated fireproofing in the mold 1. A high-temperature, high-humidity gas can be applied to the object 2 evenly. Therefore, even if the mold 1 has a complicated shape, the high-temperature and high-humidity gas spreads to every corner of the mold 1 and the binder-coated refractory 2 in the mold 1 is universally high-temperature and high-humidity gas. The condensed water can be replenished, and a mold having a uniform strength can be formed.

  Here, after filling the molding die 1 with the binder-coated refractory 2 as described above, in order to bring the molding die 1 into a reduced pressure state, for example, as shown in FIG. An air supply pipe 10 with a cock 11 closed is connected to each inlet 4 of the filled mold 1 and a suction pipe 12 is connected to the outlet 6 to make the mold 1 airtight, and in this state a vacuum is formed. By operating the pump and sucking the air in the mold 1 with the suction pipe 12, the inside of the mold 1 can be brought into a reduced pressure state. Next, when the cock 11 of the air supply pipe 10 is opened, the high-temperature and high-humidity gas supplied from the air supply pipe 10 is drawn into the mold 1 in a decompressed state all at once, and is heated to every corner in the mold 1. A high-humidity gas can be distributed.

  Next, the present invention will be specifically described with reference to examples.

(Preparation of binder coated refractory No1)
30 kg of flattered cinnabar sand heated to 145 ° C. was placed in a whirl mixer, and an aqueous solution in which 750 g of dextrin “ND-S” manufactured by Nissho Kagaku Co., Ltd. was dissolved or dispersed in 450 g of water was added as a saccharide, and kneaded for about 90 seconds. . After disintegrating, 30 g of calcium stearate was added as a lubricant, kneaded for 15 seconds, and further aerated to obtain a binder-coated refractory No1 coated with saccharide as a binder. This binder-coated refractory No1 was a smooth granular material, and the mass ratio of the binder was 2.5% by mass.

(Preparation of binder coated refractory No2)
30 kg of flattered cinnabar sand heated to 140 ° C. is placed in a whirl mixer, and 2.4 kg of water glass “Sodium silicate 1” (solid content 50% by mass) manufactured by Fuji Chemical Co., Ltd. is dissolved in 450 g of water as a water-soluble inorganic compound. Or the dispersed aqueous solution was added and kneaded for about 90 seconds. After disintegration, 30 g of calcium stearate was added as a lubricant, kneaded for 15 seconds, and further aerated to obtain a binder-coated refractory No 2 coated with a water-soluble inorganic compound as a binder. This binder coated refractory No. 2 was a smooth granular material, and the mass ratio of the binder was 4.0% by mass.

( Reference Example 1)
A mold 1 as shown in FIG. 1 in which the size of the cavity 3 was 30 cm × 10 cm × 4 cm was heated to 80 ° C. and used. First, the hopper 7 is connected to the central inlet 4 among the three inlets 4 on the upper surface of the mold 1 and the other two inlets 4 are closed, and the above-mentioned binder coated refractory No1 is attached. The mold 1 was blown and filled with an air pressure of a gauge pressure of 0.1 MPa. The temperature of the binder coated refractory No1 was 25 ° C.

Next, the air supply pipe 10 was connected to the three inlets 4 on the upper surface of the mold 1, and high temperature and high humidity gas was blown into the mold 1. As the high-temperature and high-humidity gas, one prepared with the apparatus of FIG. That is, the saturated steam having a gauge pressure of 0.3 MPa and a temperature of 143 ° C. generated by the steam generator 15 made of a boiler is heated by the superheater 20 (superheated steam generator “GE-100” manufactured by Nomura Engineering Co., Ltd.). The superheated steam with a gauge pressure of 0.35 MPa is generated at 350 ° C., and air (absolute humidity 0.0126 kg / kgDA) at 25 ° C. and a relative humidity of 63% is heated by a gas supply device 16 comprising a compressor (Co., Ltd.) It was passed through a heater for high-temperature and high-pressure hot air “SHP40 3200-1.5K” manufactured by Takenet Seisakusho, and 350 ° C. heated air was generated. Then, with the valves 18 and 19, the superheated steam is supplied at a flow rate of 40 kg / h, the heated air is 20 m ³ / h [atmospheric pressure, 0 ° C. converted value = 25.8 kg / h (= 0.3 kg water vapor / h + 25.5 kg dry air / h)] were adjusted to the respective flow rates and mixed to prepare a high-temperature and high-humidity gas. This high-temperature, high-humidity gas has a water vapor concentration (calculated as an ideal gas) of about 72%, a dew point temperature of 91 ° C., and a temperature of 350 ° C.

  Then, the mold was molded by passing high-temperature and high-humidity gas through the mold 1 for 5 seconds, 10 seconds, 20 seconds, 30 seconds, 40 seconds, 50 seconds, and 60 seconds.

(Comparative Example 1)
In the apparatus of FIG. 2 (c), the valve 19 is closed, and superheated steam generated at 350 ° C. and a gauge pressure of 0.35 MPa generated by the steam generator 15 and the superheater 20 at a flow rate of 40 kg / h for 20 seconds and 40 seconds. The mold 1 was blown for 60 seconds and 80 seconds. Otherwise, the mold was molded in the same manner as in Example 1.

In Reference Example 1 and Comparative Example 1, it was checked whether the mold could be taken out without collapsing when the mold was taken out. The case where it can be taken out without breaking is evaluated as “◯”, the case where a part of the chip is broken is evaluated as “△”, and the case where it cannot be taken out as a mold is evaluated as “×”. Shown in the column of availability.

  Further, the weight of the mold immediately after taking out from the mold was measured. At this time, the mold is opened with the bat disposed below the mold, and when the binder-coated refractory is attached to the inner surface of the mold cavity, the binder-coated refractory is discharged. The weight of the mold was also taken by the binder coated refractory received on the bat. Further, the bending strength of a test piece having a width of 20 mm, a length of 60 mm, and a thickness of 10 mm cut out from the mold was measured in accordance with the bending strength test method of JIS K6910. The results are shown in Table 1.

  Further, the strength (blurred) of the mold was measured in accordance with JIS K 5400 “Paint General Test Method” (8.4.2 Handwriting method). The results are shown in Table 1.

As can be seen from Table 1, in Reference Example 1 using a high-temperature and high-humidity gas having a temperature of 350 ° C. and a water vapor concentration of 72%, a normal mold could be obtained by blowing for 10 seconds, while overheating. In Comparative Example 1 using water vapor, it is confirmed that blowing for 60 seconds or more is necessary. Moreover, when the blowing time of Comparative Example 1 was 20 seconds, the binder was not dried and not hardened, and it contained about 15 g of water as calculated from the weight of the mold.

(Example 2)
In the apparatus of FIG. 2C, the temperature of the superheated steam and the heated air is adjusted by the superheater 20 and the heater 21, and the mixing ratio of the superheated steam and the heated air is adjusted by the valves 18 and 19, as shown in Table 2. A high temperature and high humidity gas with temperature and water vapor concentration was prepared. A mold was molded in the same manner as in Reference Example 1 except that this high temperature and high humidity gas was used and the high temperature and high humidity gas blowing time was set to 30 seconds.

(Comparative Example 2)
In the apparatus of FIG. 2C, the temperature of the superheated steam and the heated air is adjusted by the superheater 20 and the heater 21, and the mixing ratio of the superheated steam and the heated air is adjusted by the valves 18 and 19, as shown in Table 2. A high temperature and high humidity gas with temperature and water vapor concentration was prepared. A mold was molded in the same manner as in Reference Example 1 except that this high temperature and high humidity gas was used and the high temperature and high humidity gas blowing time was set to 30 seconds.

  In Example 2 and Comparative Example 2, in the same manner as described above, whether or not the mold could be taken out was checked, and the weight of the mold, the bending strength, and the strength (raginess) of the mold were measured. The results are shown in Table 5.

  As can be seen from Table 2, in Example 2 using a high-temperature and high-humidity gas having a water vapor concentration in the range of 10 to 90%, a normal mold could be formed by blowing for 30 seconds.

  On the other hand, when the high-temperature and high-humidity gas having a water vapor concentration of 95% in Comparative Example 2 was used, the binder was not dried and solidified, and could not be taken out from the mold without deforming the mold. In addition, it is confirmed that the drying time is insufficient when the blowing time is 30 seconds, and it is necessary to lengthen the blowing time. In addition, when the high-temperature and high-humidity gas having a water vapor concentration of 5% in Comparative Example 2 is used, the particles of the binder-coated refractory are not sufficiently bonded, and the mold collapses when the mold is opened. It is confirmed that the water supply to the binder is insufficient.

( Reference Example 3)
In Example 1, except that the mold temperature of the mold 1 was set to 60 ° C., 80 ° C., 100 ° C., 120 ° C., and the blowing time of the high temperature and high humidity gas was set to 30 seconds, 60 seconds, A mold was molded in the same manner as in Reference Example 1.

The condition of the surface of the mold obtained in Reference Example 3 was checked. When the surface of the mold was smooth and clean, “◯” was indicated. When there was unbound sand on a part of the mold surface, “△” was indicated. Although the central part is hardened, the case where the rough sand falls when touched on the surface of the mold is evaluated as “x”, and the results are shown in Table 3. Further, the mold weight, bending strength, and mold strength (staggered) were also measured in the same manner as described above, and the results are shown in Table 3.

  As seen in Table 3, when the mold temperature of the mold is 100 ° C. and 120 ° C. higher than the dew point temperature of 90 ° C. of the high-temperature and high-humidity gas, a problem occurs on the surface of the mold. It is confirmed that the mold temperature is preferably lower than the dew point temperature of the high temperature and high humidity gas blown into the mold.

( Reference Example 4)
A mold was molded in the same manner as in Reference Example 1 except that binder-coated refractory No2 was used instead of binder-coated refractory No1.

(Comparative Example 4)
A mold was molded in the same manner as Comparative Example 1 except that binder-coated refractory No2 was used instead of binder-coated refractory No1.

In Reference Example 4 and Comparative Example 4, whether or not the mold could be removed was checked in the same manner as described above, and the mold weight, bending strength, and mold strength (dragging) were measured. The results are shown in Table 4.

As can be seen from Table 4, in Reference Example 4 using a high-temperature and high-humidity gas having a temperature of 350 ° C. and a water vapor concentration of 69%, a normal mold could be obtained by blowing for 20 seconds, while overheating. In Comparative Example 4 using water vapor, it is confirmed that blowing for 80 seconds or more is necessary. When the blowing time of Comparative Example 4 was 20 seconds, the binder was not dried and not hardened, and it contained about 20 g of water as calculated from the weight of the mold.

(Example 5)
A mold was molded in the same manner as in Example 2 except that binder-coated refractory No2 was used instead of binder-coated refractory No1.

(Comparative Example 5)
A mold was molded in the same manner as Comparative Example 2 except that binder-coated refractory No2 was used instead of binder-coated refractory No1.

  In Example 5 and Comparative Example 5, in the same manner as described above, whether or not the mold could be taken out was checked, and the weight of the mold, the bending strength, and the strength (raginess) of the mold were measured. The results are shown in Table 5.

  As can be seen from Table 5, in Example 5 using a high-temperature and high-humidity gas having a water vapor concentration in the range of 10 to 90%, a normal mold could be formed by blowing for 30 seconds.

  On the other hand, when the high-temperature and high-humidity gas having a water vapor concentration of 95% in Comparative Example 5 was used, the binder was not dried and solidified, and could not be taken out from the mold without deforming the mold. In addition, it is confirmed that the drying time is insufficient when the blowing time is 30 seconds, and it is necessary to lengthen the blowing time. When the high-temperature and high-humidity gas having a water vapor concentration of 5% in Comparative Example 5 is used, the particles of the binder-coated refractory are not sufficiently bonded, and the mold collapses when the mold is opened. It is confirmed that the water supply to the binder is insufficient.

( Reference Example 6)
In the same manner as in Reference Example 3, except that the binder-coated refractory No2 was used instead of the binder-coated refractory No1, and the blowing time of the high temperature and high humidity gas was set to 60 seconds. Was molded.

The surface state of the mold obtained in Reference Example 6 was checked, and the mold weight, bending strength, and mold strength (dragging) were also measured in the same manner as described above. The results are shown in Table 6.

  As seen in Table 6, when the mold temperature of the mold is 100 ° C. and 120 ° C. higher than the dew point temperature of 90 ° C. of the high temperature and high humidity gas, a problem occurs on the surface of the mold. It is confirmed that the mold temperature is preferably lower than the dew point temperature of the high temperature and high humidity gas blown into the mold.

1 Mold 2 Binder coated refractory

Claims (14)

The mold is filled with a binder-coated refractory coated with a solid binder that has a sticking action in a wet state where moisture has been absorbed, and the temperature is 50 to 500 ° C., and the water vapor concentration is 10 to 60 %. By passing the wet gas through the mold, the moisture generated by condensation of the water vapor in the high temperature and high humidity gas is replenished to the binder on the surface of the binder coated refractory, and the binder coated refractory is used. The binder is caulked by the adhesive action of the binder, and continuously heated in a high-temperature and high-humidity gas having the same temperature and water vapor concentration as above to evaporate the moisture in the binder. A method for producing a mold, which comprises drying and solidifying a mold. The mold is filled with a binder-coated refractory coated with a solid binder that produces a sticking action in a wet state that absorbs moisture, and has a high temperature and high temperature of 50 to 500 ° C. and a water vapor concentration of 10 to 60%. By passing the wet gas through the mold, the moisture generated by condensation of the water vapor in the high temperature and high humidity gas is replenished to the binder on the surface of the binder coated refractory, and the binder coated refractory is used. High-temperature and high-humidity by caking by the adhesive action of the binder and by adjusting the water vapor concentration of the high-temperature and high-humidity gas that is continuously passed through the mold so as to decrease with time. A method for producing a mold, which comprises heating the body to evaporate the water content of the binder and drying and solidifying the binder . The mold is filled with a binder-coated refractory coated with a solid binder that produces a sticking action in a wet state that absorbs moisture, and has a high temperature and high temperature of 50 to 500 ° C. and a water vapor concentration of 10 to 60%. By passing the wet gas through the mold, the moisture generated by condensation of the water vapor in the high temperature and high humidity gas is replenished to the binder on the surface of the binder coated refractory, and the binder coated refractory is used. High-temperature and high-humidity gas is produced by caking by the adhesive action of the binder and adjusting the temperature of the high-temperature and high-humidity gas that is continuously passed through the mold so as to increase with time. A method for producing a mold, which comprises heating the binder to evaporate moisture of the binder and drying and solidifying the binder . The said binder is a saccharide | sugar, a water-soluble inorganic compound, and a water-soluble thermoplastic resin, The manufacturing method of the casting mold in any one of the Claims 1 thru | or 3 characterized by the above-mentioned. The method for producing a mold according to any one of claims 1 to 4, wherein the high-temperature and high-humidity gas is a mixed gas of water vapor and air. The method for producing a mold according to any one of claims 1 to 5 , wherein the high-temperature and high-humidity gas is prepared by mixing water vapor and gas while adjusting the mixing ratio. The method for producing a mold according to claim 5 or 6 , wherein superheated steam is used as the steam. The method for producing a mold according to any one of claims 1 to 5 , wherein a gas prepared by vaporizing water in a gas is used as the high-temperature and high-humidity gas. The binder coated refractory to be filled in the mold, a method of manufacturing a mold according to any one of claims 1 to 8, characterized in that to be preheated at a temperature lower than the dew point temperature of the high temperature and high moisture material . The mold manufacturing method according to any one of claims 1 to 9 , wherein the mold temperature of the mold is set to a temperature lower than the dew point temperature of the high-temperature and high-humidity gas.   The high-temperature and high-humidity gas is passed through the mold by forcibly discharging the high-temperature and high-humidity gas outside the mold while blowing the high-temperature and high-humidity gas into the mold. A method for producing the mold described above.   The method for producing a mold according to any one of claims 1 to 11, wherein saturated steam is passed through the mold before the high-temperature and high-humidity gas is passed through the mold. After passing the high temperature and high moisture material in the mold, a manufacturing method of a mold according to any one of claims 1 to 12, characterized in that to passing the gaseous low water vapor concentration than the high temperature and high moisture material to the mold. 14. The mold according to any one of claims 1 to 13, wherein the mold is filled with a binder-coated refractory, then the mold is depressurized, and then a high-temperature and high-humidity gas is passed through the mold. A method for producing a mold.

Images