JP6121121B2 - Mold manufacturing method - Google Patents

Description

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

  Currently used molds are generally hard molds such as green sand mold, high pressure mold, high speed mold, etc., which use clay as a binder, thermosetting mold, self-hardening mold, gas curing mold, precision casting mold, etc. It is classified into a special mold using an adhesive resin binder and other molds.

  These molds have their merits and demerits, but high temperature heating is necessary when producing the mold, and it takes time to cure the binder, and it is difficult to produce the mold stably in a short time. In many cases, toxic gas may be generated when the mold is produced.

  Therefore, the present applicant, when producing a mold using a binder coated refractory prepared by coating the surface of a refractory aggregate with a binder made of a thermosetting resin, the binder coated refractory is used. Proposes a method of mold making by filling the mold and blowing steam into the mold to heat the binder-coated refractory to cure the thermosetting resin binder. (For example, refer to Patent Document 1).

  That is, since water vapor has high condensation latent heat and sensible heat, when steam is blown into a mold filled with a binder-coated refractory, the condensation latent heat and sensible heat are generated when the water vapor contacts the binder-coated refractory. It is transmitted to the binder-coated refractory, and the binder-coated refractory can be instantaneously heated to cure the binder of the thermosetting resin. Therefore, it is not necessary to heat the mold at a high temperature, the mold can be produced stably in a short time, and generation of toxic gas can be prevented.

Japanese Patent No. 3563973

  When steam is blown into a mold filled with a binder-coated refractory as described above, the condensation latent heat and sensible heat of the water vapor are transmitted to the binder-coated refractory so that Condensed water is generated, and the condensed water adheres to the surface of the binder-coated refractory. Condensed water is generated until the temperature in the mold reaches around 100 ° C., but this condensed water is heated and evaporated with the steam that is blown in, and the temperature rises to 100 ° C. or more with the evaporation of the condensed water. The binder of the binder-coated refractory can be cured. This temperature rise is faster when superheated steam is used as the steam.

  Here, the 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, water vapor at a high temperature of 100 ° C. or higher is obtained in a pressurized state, and 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. In this case, the steam concentration is substantially 100%.

  As described above, the water vapor contains a large amount of water. When the water vapor is passed through the mold, a large amount of condensed water is generated in the mold. Therefore, the time required to evaporate the condensed water by heating the binder-coated refractory with water vapor that is subsequently passed through the mold becomes long, making it difficult to manufacture the mold in a short time. there were.

  This invention is made | formed in view of said point, and it aims at providing the manufacturing method of the casting_mold | template which can shorten a drying time of condensed water and can manufacture a casting_mold | template stably in a short time. Is.

In the mold manufacturing method according to the present invention, a binder-coated refractory coated with a thermosetting resin binder is filled in a mold, and the temperature is 120 ° C. or higher and the water vapor concentration is 10 to 80 %. By passing the high-humidity gas through the mold, the temperature of the binder-coated refractory is increased by the sensible heat and condensation latent heat of the high-temperature and high-humidity gas, and the same temperature and Heating with a high-temperature and high-humidity gas having a water vapor concentration evaporates the condensed water in the mold and hardens the binder of the binder-coated refractory.

  When a high-temperature and high-humidity gas is passed through a mold filled with a binder-coated refractory, the high-temperature and high-humidity gas acts on the binder-coated refractory, and the sensible heat and high-temperature and high-humidity gas of the high-temperature and high-humidity gas. The latent heat of condensation of the water vapor acts on the binder-coated refractory, and the thermosetting resin binder of the binder-coated refractory can be instantaneously heated and cured.

The high-temperature and high-humidity gas passed through the mold has a temperature of 120 ° C. or higher and a water vapor concentration of 10 to 80 %. Therefore, the water content in the high-temperature and high-humidity gas is significantly higher than that of conventionally used water vapor. The amount of condensed water generated in the mold is reduced, the time required to evaporate the condensed water can be shortened, and the molding time of the mold can be shortened. .

  In this invention, what is chosen from a phenol resin, a furan resin, an isocyanate compound, an amine polyol resin, and a polyether polyol resin can be used as said thermosetting resin.

  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.

  In addition, the present invention is characterized in that the high-temperature and high-humidity gas described above is prepared by mixing water vapor and gas while adjusting the mixing ratio.

  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 the superheated steam has a large thermal energy, the efficiency of heating the binder-coated refractory is high, 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 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.

  By forcibly discharging the high-temperature and high-humidity gas blown into the mold in this way, the efficiency of heating the binder-coated refractory through the high-temperature and high-humidity gas to the mold can be increased. .

  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 at the initial stage of passing the high-temperature and high-humidity gas through the mold, the condensation latent heat and sensible heat of the high-temperature and high-humidity gas are efficiently bonded with the binder-coated refractory. The binder coated refractory can be heated to about 100 ° C. faster and the high temperature / humidity gas is passed through the mold at the end of the process. The evaporating efficiency of the thermosetting resin is high, and the rise time to the temperature at which the binder of the thermosetting resin is cured can be shortened.

  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 the gas dried from the high-temperature high-humidity gas through the mold, the condensed water in the mold can be efficiently evaporated, and the molding time of the mold can be shortened.

  In the present invention, the binder-coated refractory may be filled in the mold by the pressure of blowing the high-temperature and high-humidity gas into the mold, and then the high-temperature and high-humidity gas may be passed through the mold.

  In this case, the binder-coated refractory can be filled in the mold using high-temperature and high-humidity gas, and the process of filling the mold with the binder-coated refractory and the high-temperature and high-temperature The process of passing the wet gas through the mold can be performed in a series of flows, and the time required for molding can be further shortened.

According to the present invention, the high-temperature and high-humidity gas passed through the mold has a temperature of 120 ° C. or higher and a water vapor concentration of 10 to 80 %. Therefore, the moisture content in the high-temperature and high-humidity gas is conventionally used. Compared to water vapor, it is much less, and less condensed water is generated in the mold, reducing the time required to evaporate the condensed water, and shortening the molding time of the mold. It can be done.

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 made of a thermosetting resin is used. Examples of the thermosetting resin include phenolic resins such as resol type, novolak type, and benzylic ether type, furan resin, isocyanate compound, amine polyol resin, polyether polyol resin, and the like. An isocyanate compound, an organic ester, hexamethylenetetramine, etc. can be blended as an agent, and a tertiary amine, a pyridine derivative, an organic sulfonic acid, etc. can be blended and used as a curing catalyst.

  When a phenol resin is used as the binder, the phenol resin can be prepared by reacting phenols and formaldehyde in the presence of a reaction catalyst.

  Here, the phenols mean phenol and phenol derivatives. For example, in addition to phenol, trifunctional compounds such as m-cresol, resorcinol, 3,5-xylenol, bisphenol A, dihydroxydiphenylmethane, etc. Tetrafunctional, bifunctional such as o-cresol, p-cresol, p-ter-butylphenol, p-phenylphenol, p-cumylphenol, p-nonylphenol, 2,4 or 2,6-xylenol An o- or p-substituted phenol can be mentioned, and a halogenated phenol substituted with chlorine or bromine can also be used. Of course, one type can be selected and used, or a plurality of types can be mixed and used.

  As formaldehydes, formalin, which is in the form of an aqueous solution, is optimal, but forms such as paraformaldehyde, acetaldehyde, benzaldehyde, trioxane, and tetraoxane can also be used. It can also be used by replacing with furyl alcohol.

  The blending ratio of the above phenols and formaldehyde is preferably set so that the molar ratio of phenols to formaldehyde is in the range of 1: 0.6 to 1: 3.5.

  When preparing a novolak-type phenolic resin, the reaction catalyst is an inorganic acid such as hydrochloric acid, sulfuric acid or phosphoric acid, or an organic acid such as oxalic acid, paratoluenesulfonic acid, benzenesulfonic acid or xylenesulfonic acid, and zinc acetate. Etc. can be used. When preparing a resol-type phenolic resin, an alkaline earth metal oxide or hydroxide can be used, and an aliphatic group such as dimethylamine, triethylamine, butylamine, dibutylamine, tributylamine, diethylenetriamine, or dicyandiamide. Primary, secondary, tertiary amine, aliphatic amines having aromatic rings such as N, N-dimethylbenzylamine, aromatic amines such as aniline and 1,5-naphthalenediamine, ammonia, hexamethylenetetramine, etc. Other divalent metal naphthenic acids and divalent metal hydroxides can also be used.

  When a novolac type phenol resin is used as a binder, it is preferable to use hexamethylenetetramine as a curing agent. The resol type phenol resin can be used alone or in combination with a novolac type phenol resin.

  When the binder is used after being diluted, alcohols, ketones, esters, polyhydric alcohols and the like can be used as a solvent for dilution.

  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. These lubricants can be used in powder or liquid form.

  Then, the binder containing the binder on the surface of the refractory aggregate by blending the refractory aggregate particles with a binder made of a thermosetting resin such as the above-mentioned phenolic resin and, if necessary, a lubricant. The layer can be coated to prepare a binder-coated refractory.

  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 of 120 ° C. or higher and a water vapor concentration in the range of 10 to 95%. 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 95%. The temperature of the high-temperature and high-humidity gas can be easily set to 120 ° C. or higher by heating after mixing a gas such as water vapor and air, or by heating the gas to a predetermined temperature in advance. .

  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 normal pressure superheated steam obtained by heating saturated steam without expanding the pressure at a constant pressure, or pressurized superheated steam obtained by heating without expanding the saturated steam. There 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 blown into the mold 1 in this way, the high-temperature and high-humidity gas comes into contact with the binder-coated refractory 2 so that the high-temperature sensible heat of the high-temperature and high-humidity gas becomes the binder-coated refractory. Heat is transferred to the object 2, and latent heat is deprived by the binder-coated refractory 2 from the water vapor in the high-temperature and high-humidity gas, and this condensation latent heat when the water vapor condenses is transferred to the binder-coated refractory 2. Heat is transferred. The temperature of the binder-coated refractory 2 rapidly rises to around 100 ° C. by the sensible heat of the high-temperature and high-humidity gas and the latent heat of condensation. The time during which the binder-coated refractory 2 is heated to around 100 ° C. is the temperature of the high-temperature and high-humidity gas, the water vapor concentration, the flow rate of blowing into the mold 1, and the binder-coated refractory 2 in the mold 1. However, it is usually a short time of about 2 to 30 seconds. The water vapor blown into the mold 1 from the injection port 4 passes through the mold 1 and is then exhausted from the discharge port 6.

  Thus, the binder-coated refractory 2 can be heated to around 100 ° C. in a short time by passing a high-temperature, high-humidity gas through the mold 1 filled with the binder-coated refractory 2. Since condensed water is generated from the high-temperature and high-humidity gas in the mold 1, it is necessary to evaporate the condensed water in the mold 1 in order to raise the binder-coated refractory 2 to a temperature of 100 ° C. or higher. However, the condensed water in the mold 1 is evaporated by heating with a high-temperature and high-humidity gas that is subsequently passed through the mold 1. Here, the high-temperature and high-humidity gas passed through the mold 1 has a temperature of 120 ° C. or higher and a water vapor concentration of 10 to 95%, which is high humidity but contains a lower amount of water than saturated water vapor. For this reason, the amount of condensed water generated by the high temperature and high humidity gas being cooled by the binder-coated refractory 2 in the mold 1 and decreasing in temperature can be reduced. The time for evaporating the condensed water is short.

  When the condensed water in the mold 1 evaporates, the binder-coated refractory 2 is rapidly heated to a temperature of 100 ° C. or higher by the high-temperature and high-humidity gas, and the binder made of a thermosetting resin is brought to a temperature higher than the curing temperature. The mold can be molded by bonding particles of the binder-coated refractory by melting and curing the binder made of a thermosetting resin. .

  The time from when the high-temperature and high-humidity gas passes through the mold 1 filled with the binder-coated refractory 2 to when the thermosetting resin binder is cured and the molding of the mold is completed is high temperature and high humidity. It varies depending on the body temperature and water vapor concentration, the flow rate of blown into the mold 1, the filling amount of the binder-coated refractory 2 in the mold 1, etc., but it is usually a short time of about 10 seconds to 1 minute. . The mold thus molded can be taken out by opening the mold 1.

  As described above, the high-temperature and high-humidity gas needs to have a water vapor concentration of 95% or less so that a large amount of condensed water is not generated in the mold 1. However, if the water vapor concentration is low, the latent heat of condensation of water vapor in the high-temperature and high-humidity gas will be low, and the heating efficiency by the high-temperature and high-humidity gas may be reduced, so the water vapor concentration needs to be 10% or more. . Thus, in this invention, although the water vapor | steam density | concentration of high temperature high humidity gas is set to the range of 10-95%, the range of 20-90% is preferable and the range of 30-80% is more preferable.

  Moreover, when the temperature of the high temperature and high humidity gas is low, the efficiency of heating the binder coated refractory 2 or evaporating the condensed water with the high temperature and high humidity gas is deteriorated. Since it takes a long time to cure the agent, the temperature of the high temperature and high humidity gas needs to be 120 ° C. or higher. The upper limit of the temperature of the high-temperature and high-humidity gas is not particularly set, but it is desirable that the temperature is equal to or lower than the thermal decomposition temperature of the binder thermosetting resin of the binder-coated refractory 2.

  In the above embodiment, the high-temperature and high-humidity gas passed through the mold 1 is the same in temperature and water vapor concentration from the initial stage to the late stage 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. As described above, when the high-temperature and high-humidity gas has a high water vapor concentration at the initial stage of passing the high-temperature and high-humidity gas through the mold 1, the condensation latent heat of the water vapor in the high-temperature and high-humidity gas is efficiently converted into the binder-coated refractory. It is thus possible to heat the binder coated refractory to around 100 ° C. faster. In the latter stage of passing high-temperature and high-humidity gas through the mold, if the water vapor concentration of the high-temperature and high-humidity gas is low, the efficiency of evaporating the condensed water increases, and the thermosetting resin binder is cured. The time for raising the temperature can be shortened.

  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.

  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 a gas having a lower water vapor concentration than the high-temperature and high-humidity gas is allowed to pass through the mold 1. Good. As this gas, any gas other than water vapor may be used, and heated air, other heated nitrogen gas, or the like can be used. Since this gas is a dry gas whose humidity is lower than that of a high-temperature and high-humidity gas, the efficiency of evaporating the condensed water in the mold 1 is high, and the time for evaporating and removing the condensed water can be shortened. is there. Moreover, the efficiency of evaporating the condensed water in the shaping | molding die 1 can be improved more by heating and using this gas. The temperature of the heated gas is not particularly limited, and may be any temperature that is not lower than the curing temperature of the thermosetting resin of the binder coated refractory and does not cause thermal decomposition of the thermosetting resin.

  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 a high-temperature, high-humidity gas is increased, and a mold can be produced in a shorter time.

  In the above embodiment, the mold 1 is filled with the binder-coated refractory 2 and then the high-temperature and high-pressure gas is blown into the mold 1, but the pressure at which the high-temperature and high-humidity gas is blown into the mold is used. Then, the binder-coated refractory may be filled in the mold. In this case, the mold can be molded by blowing and filling the binder-coated refractory with a high-temperature and high-humidity gas into the mold and subsequently passing the high-temperature and high-humidity gas through the mold. Is.

  For example, in the apparatus of FIG. 1A, high-temperature and high-humidity gas is supplied to an air supply pipe 9 with a cock 8 connected to a hopper 7. Then, after the nozzle port 7a of the hopper 7 is matched with the injection port 4 of the mold 1, the cock 8 is switched from the closed state to the open state, whereby high-temperature and high-humidity gas is blown into the hopper 7 and pressurized. The binder coated refractory 2 in the hopper 7 can be blown into the mold 1 and filled. Next, when the supply of the high-temperature and high-humidity gas to the air supply pipe 9 is continued as it is, the high-temperature and high-humidity gas is blown into the mold 1 from the injection port 4 through the hopper 7 and the nozzle port 7a. The binder-coated refractory 2 filled in the mold 1 can be heated with a high-temperature and high-humidity gas, and can be molded in the same manner as described above.

  Therefore, in this case, the step of filling the mold 1 with the binder-coated refractory 2 and the step of passing the high-temperature high-humidity gas through the mold 1 can be performed in a series of flows. After filling the mold 1 with the binder-coated refractory 2 as in the form, disconnect the hopper 7 from the mold 1 and connect the air supply pipe 10 to the mold 1 as shown in FIG. Thus, it is not necessary to fill the binder 1 with the binder-coated refractory 2 and supply the high-temperature and high-humidity gas in separate steps, such as supplying the high-temperature and high-humidity gas to the molding die 1. It is possible to further reduce the time required.

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

(Production example of binder coated refractory)
30 kg of flattery sand heated to 145 ° C. is placed in a whirl mixer, 540 g of resol type phenolic resin (“LT-15” manufactured by Lignite Co., Ltd.) is added to this, kneaded for 30 seconds, and then 450 g of water is added. Kneaded thoroughly. Subsequently, 30 g of calcium stearate was further added and kneaded for 30 seconds, followed by aeration to obtain a binder-coated refractory to which 1.8% by mass of a phenol resin having a fusion point of 98 ° C. was adhered.

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 preheated to 150 ° C. and used. Temperature sensors are provided at the three discharge ports 6 on the lower surface of the mold 1 so that the temperature of the gas discharged from the discharge port 6 can be measured.

  First, of the three injection ports 4 on the upper surface of the mold 1, the hopper 7 is connected to the central injection port 4 and the other two injection ports 4 are closed. The molding die 1 was blown and filled with an air pressure of a gauge pressure of 0.1 MPa.

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.

  The mold was molded by passing high-temperature and high-humidity gas through the mold 1 for 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 having a temperature of 350 ° C. and a gauge pressure of 0.35 MPa generated by the steam generator 15 and the superheater 20 is blown into the mold 1 at a flow rate of 40 kg / h. did. Otherwise, the mold was molded in the same manner as in Example 1.

  In Example 1 and Comparative Example 1 described above, the temperatures of the three outlets 6 of the mold 1 at the end of the blowing of the high-temperature and high-humidity gas or the superheated steam were measured with a temperature sensor, and the average values are shown in Table 1. Shown in

  Also, the odor when the mold was taken out from the mold 1 was evaluated by the operator's sense of smell, and it was checked whether the mold could be taken out without collapsing when the mold was taken out. The results are shown in Table 1, where “◯” indicates that the material can be taken out without collapsing, “Δ” indicates that a part of the chip is missing, and “x” indicates that the material cannot be taken out as a mold due to collapse.

  Further, the weight of the removed 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, for 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, the bending strength was measured in accordance with the bending strength test method of JIS K 6910, and the results are shown in Table 1.

  As can be seen in Table 1, in 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 having high strength could be obtained by blowing for 30 seconds. Thus, in Comparative Example 1 using superheated steam, it is confirmed that blowing for 40 seconds or more is necessary.

(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 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 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 and bending strength of the mold were measured. 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 2.

  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 95%, a normal mold could be formed by blowing for 30 seconds. On the other hand, when a high-temperature and high-humidity gas having a water vapor concentration of 5% or 98% is used as in Comparative Example 2, the binder is not sufficiently cured and it is difficult to take out the mold from the mold. It is confirmed that when the blowing time is 30 seconds, the binder is not sufficiently heated and the blowing time needs to be increased.

1 Mold 2 Binder coated refractory

Claims (10)

Filling the mold with a binder-coated refractory coated with a thermosetting resin binder and passing a high-temperature and high-humidity gas at a temperature of 120 ° C. or higher and a water vapor concentration of 10 to 80 % through the mold. The temperature of the binder-coated refractory is increased by the sensible heat and condensation latent heat of the high-temperature, high-humidity gas, and continuously heated with the high-temperature, high-humidity gas with the same temperature and water vapor concentration as above. A method for producing a mold, characterized in that the condensed water in the mold is evaporated and the binder of the binder-coated refractory is cured. Filling the mold with a binder-coated refractory coated with a thermosetting resin binder, and passing a high-temperature and high-humidity gas with a temperature of 120 ° C. or higher and a water vapor concentration of 10 to 80% through the mold. The temperature of the binder-coated refractory is increased by the sensible heat and condensation latent heat of the high-temperature, high-humidity gas, and the water vapor concentration of the high-temperature, high-humidity gas that is continuously passed through the mold is adjusted to decrease with time. Then, by heating through a mold, the condensed water in the mold is evaporated and the binder of the binder-coated refractory is cured . The method for producing a mold according to claim 1 or 2 , wherein the thermosetting resin is selected from a phenol resin, a furan resin, an isocyanate compound, an amine polyol resin, and a polyether polyol resin. The method for producing a mold according to any one of claims 1 to 3, 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 4 , 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 4 or 5 , wherein superheated steam is used as the steam. The method for producing a mold according to any one of claims 1 to 4 , wherein a gas prepared by vaporizing water in a gas is used as the high-temperature and high-humidity gas. While supplying the high temperature and high moisture material in the mold by forcing discharging high temperature and high moisture material to the outside of the mold, any one of claims 1 to 7, characterized in that through the high temperature and high moisture material to the mold A method for producing the mold according to 1. 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 8, characterized in that to passing the gaseous low water vapor concentration than the high temperature and high moisture material to the mold.   10. The binder-coated refractory is filled in the mold by the pressure of blowing the high-temperature and high-humidity gas into the mold, and then the high-temperature and high-humidity gas is passed through the mold. The manufacturing method of the casting_mold | template in any one of.

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