JPS6356186B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a ceramic molded body, which manufactures a ceramic molded body before firing.

In general, ceramics are non-metallic inorganic solid materials manufactured by heat treatment, and have excellent heat resistance and durability, as well as high mechanical strength.
Since ancient times, it has been used as molded objects in various shapes such as ceramics, refractories, and glass. Also, in recent years,
As it became clear that ceramics had superior properties such as electrical, magnetic, optical, and biochemical functions in addition to the above properties, new uses for ceramics were developed one after another, and new ceramics Also called fine ceramics, a large number of products such as electronic parts, magnetic materials, optical elements, artificial bones, and artificial tooth roots with sophisticated forms and shapes have come to be provided.

Along with the development of this new use, various methods for manufacturing ceramic molded bodies have been proposed and put into practical use. However, advances in science and technology, including electronics centered on integrated circuits (ICs) and large-scale integrated circuits (LSIs), and the development of industry have inevitably made the requirements for various materials extremely sophisticated, and ceramics Even in the field of technology, the limits of conventional technology are being exceeded to meet this demand. Therefore, in order to meet the expectations for ceramics, which have a variety of possibilities, it is essential to develop new manufacturing technologies.
We look forward to its early realization.

Conventional manufacturing methods for ceramic molded bodies, with the exception of manufacturing methods for some products such as glass products that are molded in a high-temperature molten state, use inorganic solid materials as starting materials and mechanically crush, classify, and mix them. The raw material preparation process involves preparing a raw material powder, and the raw material powder is processed into a powder form or by adding water, an organic binder, etc. to the powder as appropriate depending on various molding methods such as pressure molding, extrusion molding, tape molding, and casting molding. and granulation,
It consists of a molding process in which a plastic material or slurry material is made into a plastic material or slurry material by operations such as sizing, kneading, and stirring, and then processed into a molded object of a certain shape. Following this molding process, the molded body is subjected to processing operations such as cutting, barrel polishing, and drying if necessary.
Ceramic products are obtained through a firing process that involves heating and firing at high temperatures.

However, in order to obtain the desired properties such as mechanical strength and durability, conventional methods for producing ceramic molded bodies exclusively employ inorganic powder as the starting material, and they also differ in chemical composition or constituent mineral phase. After mixing the powders to match the target chemical composition, this mixed powder is molded according to the manufacturing method described above, but the problem with the conventional manufacturing method is that the reaction during the next firing process of the molded product is solid. Because the process proceeds through the contact interface of particles or the liquid phase slightly present at the contact interface, heat treatment at high temperatures and for a long time is required to make ceramic products uniform in composition. It is extremely difficult to achieve a uniform composition, and the characteristics of ceramics cannot be fully exhibited.

Therefore, as a means to solve this problem, the starting raw material powder is pulverized into as fine particles as possible and thoroughly mixed, and then this mixed powder is calcined at a temperature lower than the final firing temperature, and then this calcined product is The method of pulverizing, mixing, and then calcining is repeated several times to homogenize the component composition, and then this calcined powder is molded and fired. Even with complex processing methods, the compositional or structural homogeneity of the final product ceramics is not sufficient, and the presence of partial heterogeneity and defects is unavoidable, resulting in variations in the functions and properties of the ceramics. This results in a reduction in product yield and reliability in terms of quality, resulting in extremely large economic losses.

Another disadvantage of the conventional method is that the starting material is a powdered solid material, so a large amount of grinding power is required to obtain this fine powder, and there is also the risk of contamination by foreign matter due to wear of balls, liners, etc. during grinding. It is impossible to avoid this, making it difficult to produce high-purity raw materials, and processing the dust and powder generated during pulverization is difficult and complicated. Complete continuity is essentially impossible, and process rationalization and automation are hindered.

The present invention solves the problems and drawbacks of the conventional methods described above. (1) A homogeneous molded body can be obtained without passing through solid powder, and (2) A ceramic product having a complex composition such as a composite oxide can be produced. (3) Ultra-high purity ceramic products can be easily produced; (4) Ceramic molded products with smooth and homogeneous surfaces can be produced, especially in the form of films, fibers, or (5) An object of the present invention is to provide a method for manufacturing a ceramic molded body, which can be manufactured into a hollow molded body, and (5) can realize a continuous ceramic manufacturing process.

In order to achieve the above object, the present inventors have conducted extensive research and found that a colloid containing a non-metal or metal oxide, hydroxide, or a hydrated compound thereof as a dispersed phase, for example, Si, Al, Mg, Ti, etc. It has been found that a highly pure and dense molded product can be obtained by injecting the colloid into a mold and then volatilizing the dispersion medium of the colloid. When the medium is volatilized, the shrinkage rate of the molded product is large, causing cracks and deformation in the molded product.As a result of further research to develop a new molding drying method, we were able to complete the present invention. Ivy.

In addition, in this specification, colloid is 10 to
A system in which solid particles with a size of 10,000 angstroms (Å) (1 to 1,000 nm) are dispersed in a liquid phase.

The present invention uses a colloid having one or more types of inorganic substances as a dispersed phase as a starting material, a liquid having a lower density than the colloid and dissolving a dispersion medium of the colloid as an upper liquid, and a liquid having a higher density than the colloid. is the lower layer liquid, and the colloid is around the interface of the two-layer liquid formed by the upper liquid and the lower liquid (hereinafter, this "around the interface of the two-layer liquid" will be abbreviated as the "two-liquid interface part"). The dispersion medium of the colloid is partially or entirely removed at this two-liquid interface, and the dispersed phase remaining in the colloid is formed as a molded body.

Note that it is preferable that the colloid is continuously supplied to the two-liquid interface.

Further, it is preferable that the upper liquid contains one or more kinds of organic compounds.

Moreover, it is preferable that this organic compound contains one or more selected from alcohols, ketones, and aldehydes.

Moreover, it is preferable that the alcohol is an alcohol having 6 or less carbon atoms.

Moreover, it is preferable that the ketones are ketones having 6 or less carbon atoms.

Moreover, it is preferable that the aldehyde is an aldehyde having 5 or less carbon atoms.

Further, it is preferable that the lower liquid contains one kind or a mixture of two or more kinds selected from organic halogen compounds.

Moreover, it is preferable that the lower layer liquid consists of mercury or a fusible metal.

Further, it is preferable that the melting point of the fusible metal is 90°C or lower.

Further, it is preferable to use a colloid obtained by hydrolyzing one or more alkoxides as the starting material.

Furthermore, it is preferable to use a mixture of two or more colloids obtained by hydrolyzing one or more alkoxides as the starting material.

To further explain the present invention, the dispersion medium of the colloid supplied to the two-liquid interface is absorbed by the upper liquid and rapidly changes from a sol state to a gel state.
As a result, the above-mentioned colloid maintains its shape at the time of supply, is supported by the higher-density lower liquid, and moves across the two-liquid interface, and subsequently the dispersion medium is absorbed and removed from the above-mentioned colloid, and the dispersion phase is sequentially formed as the main component. Become a body. When the dispersion medium is desorbed from this colloid, a considerable amount of shrinkage occurs in the molded product, but since the molded product is located at the interface between the two liquids and the shrinkage is not restrained, no cracks or distortions occur in the molded product. A homogeneous molded product with a smooth surface can be obtained, and if the colloid is continuously supplied, it is possible to obtain a continuous molded product in the shape of a film, fiber, or other shape.

The temperature of the two-liquid interface to which the colloid is supplied is set higher than the freezing points of the colloid dispersion medium and the two-layer liquid, and lower than the boiling points thereof.

Further, although the above-mentioned two-liquid interface may be at normal pressure, it is considered that it can also be carried out under increased pressure or reduced pressure.

Further, after the colloid has gelled, the dispersion medium has been removed, and the molded body has been cured to the extent that it will not deform even if a considerable external stress is applied to it, the molded body will be shaped according to its shape. (a) rolled up in the liquid, (b) or pulled up into the space above the liquid, (c) or provided with an outlet in the liquid container and taken out from the outlet, (d) or after draining the liquid. removed from the container.

The molded body is then dried to remove the dispersion medium remaining in the molded body and/or the two-layer liquid that has entered the molded body. This drying method is performed by leaving the material in air at room temperature and pressure, or, if necessary, in an atmosphere with appropriately selected temperature or pressure conditions.

The colloidal dispersed phase used in the present invention is not particularly limited and is determined solely by the intended use and characteristics of the product, but includes, for example, Al, Mg, Si, Ti, Ba,
Examples include oxides, hydroxides, or hydrated compounds of nonmetals or metals such as Pb, Zn, Zr, and rare earth metals, and may also be mixtures thereof.

Further, the colloid is preferably a substance obtained by hydrolyzing one or more alkoxides. Here, the alkoxide refers to a compound in which hydrogen in an alcohol is replaced by a metal element, silicon, phosphorus, arsenic, selenium, tellurium, boron, or sulfur.

For example, 100 mol of water is added to 1 mol of aluminum isopropoxide [Al(i-C ₃ H ₇ O) ₃ ] obtained by reacting metallic aluminum with isopropyl alcohol, and the mixture is hydrolyzed at about 80°C for 30 minutes. By generating boehmite [AlOOH] and peptizing it by adding a small amount of hydrochloric acid, a stable boehmite sol or pseudo-boehmite sol can be obtained. A desired molded article is obtained by supplying this sol to the two-liquid interface.

The advantage of molding a sol obtained by hydrolyzing an alkoxide as a starting material becomes even more pronounced in the production of ceramic molded bodies made of composite oxides. In other words, composite oxides can be easily synthesized at low temperatures of 100°C or less by hydrolyzing a mixture of alkoxides made of multiple metal elements that make up this oxide, and, as in the case of boehmite, appropriate peptization Depending on the treatment, a sol, in other words a colloid, can be formed.

For example, in the case of barium titanate (BaTiO ₃ ), which is widely used as a high dielectric constant material, barium isopropoxide and titanium isopropoxide are weighed out at a molar ratio of 1:1. Mix this well in benzene solution and add 60 to 80
After a sufficient reaction at ℃, water is added for hydrolysis to obtain a white BaTiO ₃ precipitate. This white precipitate consists of extremely fine particles, similar to other compounds obtained by hydrolysis of alkoxides, and a stable colloid can be easily obtained by peptization, and the molding method of the present invention A highly preferred starting material is provided.

On the other hand, the conventional synthesis of BaTiO ₃ uses powders of barium carbonate (BaCO ₃ ) and titanium dioxide (TiO ₂ ) as starting materials, which are thoroughly mixed and then pressure _- molded and fired. It only occurs when heated to 700℃ or higher, and at least
This reaction will not be completed unless it is heated to about 1100°C, and high-temperature treatment of 1350°C or higher is required to achieve sufficient sintering. Furthermore, in the conventional method, as seen in the firing process of ferroelectric composite oxides such as BaTiO ₃ and Pb (Zr, Ti) O ₃ ,
Volume expansion accompanied by the formation of the mineral phase and subsequent firing contraction occur, and the compact undergoes mechanical stress due to the significant volume change during this firing process.
Negative effects such as distortion and cracks occur.

On the other hand, if the above-mentioned alkoxide is used as the starting material in the production method of the present invention, it is possible to
BaTiO ₃ is generated, and the firing temperature of the compact is increased to 1200℃.
Ceramic products with a higher degree of sintering than conventional methods can be obtained even if the temperature is lowered to low temperatures, and there is no phase change during the firing process, making it easy to produce homogeneous, dense, yet ultra-high purity BaTiO ₃ ceramic products. Obtainable.

Furthermore, even when producing ceramic products with complex compositions, by homogeneously mixing two or more types of colloids obtained by hydrolyzing a mixture of one or more types of alkoxides, it is possible to achieve excellent homogeneous properties. It is possible to stably produce products with high yield. The above method is extremely effective when applied, for example, to the production of positive temperature characteristic (PTC) thermistors, which require strict control and homogenization of the composition.

In addition, using alkoxide as a starting material
As a result of the mixing of each component in an organic solvent, homogenization can be carried out extremely easily, and the starting materials ( It has the advantage of being able to create colloids (colloids), and it has the advantage of forming a continuous production line for ceramics, from the subsequent molding process to the firing process.

Note that the starting materials for the production method of the present invention are not limited to those obtained by hydrolysis and peptization of the alkoxides, and include, for example, adding aqueous ammonia to metal salts to form metal hydroxides, Various methods can be used, such as making this hydroxide into a colloid using a higher alcohol or ester as a dispersion medium. Furthermore, a homogeneous mixed colloid can be easily produced from a plurality of colloids that are produced using different colloidalization techniques, and this mixed colloid can also be used as a starting material in the present invention.

In addition, if a highly flexible molded body is required in the next process of removing the dispersion medium, molding process, or subsequent firing process, a flexible organic binder is added to the colloid in advance. The purpose can be achieved by mixing an appropriate amount and then molding. Examples of the organic binder include polyvinyl alcohol, polyvinyl butyral, methylcellulose, polyacrylic acid, polymethacrylic acid, and the like. Furthermore, prior to molding the colloid, various thickeners or dispersants may be added and mixed in order to adjust the viscosity of the colloid to a range suitable for molding.

Examples of the liquid constituting the upper layer of the two-layer liquid to which the colloid is continuously supplied include organic compounds such as alcohols, aldehydes, and ketones. This upper layer liquid must absorb the continuously supplied colloidal dispersion medium, cause solidification and hardening by gelation of the molded body, and subsequently remove the dispersion medium from the molded body. When the dispersion medium is composed of water and/or benzene, an organic compound with a small number of carbon atoms is preferable, and the density of the colloid is generally about 1.1 to 1.3 g/cm ³ .
Preferably, the density is 1.0 g/cm ³ or less.

The alcohols are preferably compounds having 6 or less carbon atoms, such as methyl alcohol, ethyl alcohol, furfuryl alcohol, propyl alcohol, butyl alcohol, hexyl alcohol, and isomers of these compounds.

The aldehydes are preferably compounds having 5 or less carbon atoms, such as acetaldehyde,
Includes propionaldehyde, butyraldehyde, acrolein, furfural, and isomers of these compounds.

The ketones are preferably compounds having 6 or less carbon atoms, such as acetone, ethyl methyl ketone, propyl methyl ketone, methyl vinyl ketone, cyclohexanone, and isomers of these compounds.

The compound constituting the upper layer liquid may be one of the various compounds mentioned above, or may be a mixed liquid obtained by mixing a plurality of the above compounds. The selection of this organic compound takes into account various conditions such as the type and content of the dispersion medium constituting the colloid, the colloid supply rate, the cross-sectional area and shape of the compact, the speed of removal of the dispersion medium, and the type of lower liquid. be exposed.

Further, it is essential that the liquid constituting the lower layer of the two-layer liquid has a higher density than the colloid,
As mentioned above, the density of colloids is generally between 1.1 and 1.3.
g/cm ³ , so it is preferably at least 1.4 g/cm ³ or more. For example, if it is necessary to increase the smoothness of a sheet-shaped molded product, select a liquid with as high density as possible. An appropriate compound may be selected from the compounds described below in consideration of the shape of the molded article and the properties to be imparted.

Examples of this lower layer liquid include organic halogen compounds (eg, methylene iodide, tribromobenzene, diiodobenzene, bromoform, etc.). In particular, when the organic halogen compound is employed as the lower layer liquid, it is preferable to select an alcohol having low mutual solubility with the organic halogen compound as the upper layer liquid. Furthermore, as the lower layer liquid, for example, mercury or various fusible alloys (for example, Sn as represented by Wood alloy and Plant alloy),
Made of Pb, Cd, Bi, Zn, In, Hg, etc. with a melting point of 90
℃ or below).

This mercury or various fusible metals has a higher density and a higher surface tension than organic halogen compounds, so the surface can support the colloid more stably and reliably. Note that the use of fusible alloys with melting points exceeding 90°C, except in special cases, may cause undesirable effects such as excessively high de-dispersion medium speed and drying speed of the molded product, and the generation of air bubbles within the molded product. Therefore, it is better to avoid adopting it.

Furthermore, as a method for supplying the colloid to the two-liquid interface, for example, a method of extruding the colloid to the two-liquid interface from a mouthpiece or nozzle having a predetermined cross-sectional shape while pressurizing the colloid, etc. is employed.

The continuously supplied colloid is formed into a molded body while maintaining the extruded shape at the mouthpiece due to gelation and condensation, and is supported by the lower liquid having a higher density than the molded body. It moves in the upper liquid at the two-liquid interface, receives the dedispersion medium, and is continuously carried out of the system by a winding device, guide rollers, etc. placed outside the two-liquid liquid. The desired ceramic product is then obtained by firing the compacted body in a tunnel kiln or the like, and if necessary, cutting is performed prior to the firing process to continuously and efficiently produce high-performance ceramic products. Manufactured.

The cross-sectional shape of this molded body can be determined by the shape of the mouthpiece as described above, and molded bodies of various shapes such as sheet, rod, tube, honeycomb, and fiber shapes are continuously manufactured. In addition to the above-mentioned flexible binder, the molded product has the following properties:
It is also possible to obtain ceramic products with various cross-sectional shapes by pressing a sheet-like molded body.

As described above, according to the present invention, (1) Since solid powder is not used, there is no need for a pulverization process or a calcination process prior to molding, and there is almost no contamination of foreign matter, resulting in a homogeneous and ultrahigh-quality product. (2) Even in the case of ceramic molded bodies with complex compositions such as complex oxides, it is possible to produce molded bodies of high purity, by mixing each component to form a raw material colloid and removing the dispersion medium. (3) The raw material colloid is transferred to the two-liquid interface from a mouth or nozzle with various cross-sectional shapes. By supplying the
(4) Since molding is performed continuously in a liquid, there is an excellent effect that a continuous manufacturing line for ceramics can be formed up to the firing process.

Hereinafter, in order to clarify the aspects of the present invention, examples and comparative examples will be shown and more specifically explained.
The examples shown here are merely examples and do not limit the scope of the present invention.

[Example 1] Commercially available alumina sol and silica sol were mixed with water as a dispersion medium and had a mullite composition (in molar ratio Al ₂ O ₃ :SiO ₂ =
3:2) to prepare a raw material colloid.

Next, the raw material colloid with the above mullite composition was continuously extruded from a nozzle to a thickness of 100 μm and a width of 30 mm onto the two-liquid interface maintained at 20°C with butanol as the upper liquid and methylene iodide as the lower liquid, and the dispersion medium The water was removed with butanol as the upper liquid, and the raw material colloid was gelled, then pulled out of the two-layer liquid and left in air at 40°C and 1 atm to dry to obtain a molded sheet.

This formed sheet was fired at 1300°C to obtain a mullite ceramic sheet having a thickness of 26 μm after firing.

This mullite ceramic sheet was homogeneous and had a surface roughness of 0.3 μm or less, had no through holes, and had a surface roughness sufficient to be used without polishing.
It was also confirmed using an X-ray diffraction device that the mineral composition consisted only of ultra-high purity mullite.

[Comparative Example 1] A raw material colloid having the same mullite composition as in Example 1 is once powdered and calcined at 1000°C, and then a calcined powder is produced.

This calcined powder was then molded using a tape molding method to obtain a mullite ceramic sheet with a thickness of 30 μm after firing. It had to be fired at a high temperature of 1450°C, 150°C higher than the firing temperature of Example 1.

Furthermore, the obtained mullite ceramic sheet has many through-holes and has a surface roughness of 1.0~
The sheet had a rough surface of 2.0 μm and required a long polishing time to obtain a smooth surface of 0.3 μm or less, and its mechanical strength was significantly weaker than that of the sheet made in Example 1, making it difficult to handle. .

[Example 2] The alumina sol used in Example 1 is prepared into a raw material colloid using water as a dispersion medium.

Next, the above raw material colloid is applied through the nozzle to the two-liquid interface maintained at 5°C, with isobutyraldehyde as the upper liquid and mercury as the lower liquid.
Continuously extrude through 30 mm, remove the water in the dispersion medium with isobutyraldehyde in the upper layer liquid, and gel the raw material colloid, then pull it out of the two-layer liquid and leave it in the air at room temperature and pressure to dry. A molded sheet was obtained.

This formed sheet was fired at 1400°C to obtain an alumina ceramic sheet having a thickness of 12 μm after firing.

This alumina ceramic sheet was homogeneous, had a surface roughness of 0.3 μm or less, and had no through holes at all. It was also confirmed using an X-ray diffraction device that the mineral composition consisted only of ultra-high purity alumina. Furthermore, although the thickness was approximately half that of the ceramic sheet of Example 1, it had sufficient strength for practical use without causing any trouble in handling.

[Comparative Example 2] The same alumina sol as in Example 2 was once powdered and then molded using a tape molding method to have the same thickness and width as in Example 2, but the molded product was thin and weak in strength. Therefore, the molded product could not be peeled off from the casting tape, and a ceramic sheet with the same thickness as in Example 2 could not be obtained.

[Example 3] Water adjusted to pH 2 to 4 was added to aluminum isopropoxide obtained by reacting metallic aluminum with isopropyl alcohol, and the aluminum was hydrolyzed to obtain a boehmite sol.

On the other hand, magnesium methoxide obtained by reacting metallic magnesium with methanol was hydrolyzed by adding water to obtain brucytosol.

These two have a spinel composition (Al ₂ O ₃ in molar ratio:
MgO=1:1) to prepare a raw material colloid.

Next, a raw material colloid with the above spinel composition is applied to the two-liquid interface maintained at 60°C with cyclohexanone as the upper liquid and plant alloy (48% Bi, 23% Pb, 23% Sn, 6% Hg) as the lower liquid.
It was continuously extruded to a size of 40 μm and a width of 50 mm, the dispersion medium water was removed by the upper liquid cyclohexanone, and the raw material colloid was gelled, then it was pulled out of the two-layer liquid and left in air at room temperature and normal pressure. It was dried to obtain a molded sheet.

This formed sheet was fired at 1200°C to obtain a spinel ceramic sheet having a thickness of 8 μm after firing.

This spinel ceramic sheet was homogeneous, had a surface roughness of 0.3 μm or less, and had no through holes at all. It was also confirmed using an X-ray diffraction device that the mineral composition consisted only of ultra-high purity spinel. Moreover, although the thickness was thinner than that of the ceramic sheets of Examples 1 and 2, it had practically sufficient strength without any trouble in handling, as in Examples 1 and 2.

[Comparative Example 3] A raw material colloid with the same spinel composition as in Example 3 was once powdered and then processed into Example 3 using a tape molding method.
However, for the same reason as Comparative Example 2, it was not possible to obtain a spinel ceramic sheet.

Note that the temperature at which spinel ceramic molded bodies are generally fired by the tape molding method is 1400°C, so in Example 3, the spinel ceramic sheet was able to be obtained at a firing temperature 200°C lower than this temperature.

[Example 4] Silica sol obtained by adding water to ethyl orthosilicate and hydrolyzing it, the boehmite sol used in Example 3, and brucito sol were mixed with cordierite (cordierite, 2MgO・2Al ₂ O ₃・5SiO ₂ ) (MgO:Al ₂ O ₃ :SiO ₂ =2:2:5 in molar ratio) to prepare a raw material colloid.

Next, a raw material colloid with the above cordierite composition is passed through a nozzle to the two-liquid interface maintained at 5°C, with methanol as the upper liquid and mercury as the lower liquid.
After extruding into a tube shape with a thickness of 500 μm and 500 μm, water in the dispersion medium is removed with methanol in the upper layer liquid, and the raw material colloid is gelled, and then pulled out from the two-layer liquid at 50°C and 1 atm containing methanol vapor. A molded tube was obtained by drying in the air.

This molded tube was fired at 1300°C to obtain a cordierite ceramic tube having a thickness of 100 μm after firing.

A halogen compound (carbon tetrachloride) dissolved in the methanol of the upper layer liquid was added to the raw material colloid, and the specific gravity of the upper layer liquid was adjusted in advance to 1.2 g/cm ³ to prevent the tube from deforming.

[Comparative Example 4] An attempt was made to powder a raw material colloid with the same cordierite composition as in Example 4, and then to mold it by extrusion molding to the same diameter and thickness as in Example 4. The deformation was so severe that it was impossible to make it into a tube shape.

[Example 5] Water is added to 100 parts by weight of the boehmite sol used in Example 3 and 15 parts by weight of the polyacrylic acid-based hydrophilic binder to prepare a raw material colloid.

Next, the above raw material colloid is extruded through a nozzle with a diameter of 50 μm to the two-liquid interface maintained at 20°C, with butanol as the upper liquid and methylene iodide as the lower liquid, and water as a dispersion medium is desorbed by the butanol as the upper liquid. After gelling the raw material colloid, it was pulled out of the two-layer liquid and allowed to stand in air at room temperature and pressure to dry, yielding shaped fibers.

This shaped fiber was wound up and fired at 700°C to obtain an aluminum fiber.

Claims (1)

[Scope of Claims] 1 A colloid having one or more kinds of inorganic substances as a dispersed phase is used as a starting material, a liquid having a lower density than the colloid and dissolving the dispersion medium of the colloid is used as an upper liquid, and a liquid having a density lower than that of the colloid A liquid with a large amount of water is used as a lower liquid, and the colloid is supplied around the interface of a two-layer liquid formed by the upper liquid and the lower liquid, and a part of the dispersion medium of the colloid is supplied around the interface of the two-layer liquid. Alternatively, a method for producing a ceramic molded body in which the entire colloid is desorbed and the dispersed phase remaining in the colloid is formed as a molded body. 2. The method for producing a ceramic molded body according to claim 1, wherein the colloid is continuously supplied around the interface of the two-layer liquid. 3. The method for producing a ceramic molded body according to claim 1 or 2, wherein the upper layer liquid contains one or more organic compounds. 4. The method for producing a ceramic molded article according to claim 3, wherein the organic compound contains one or more selected from alcohols, ketones, and aldehydes. 5. The method for producing a ceramic molded body according to claim 4, wherein the alcohol is an alcohol having 6 or less carbon atoms. 6. The method for producing a ceramic molded body according to claim 4, wherein the ketones are ketones having 6 or less carbon atoms. 7. The method for producing a ceramic molded body according to claim 4, wherein the aldehyde is an aldehyde having 5 or less carbon atoms. 8. The method for producing a ceramic molded article according to any one of claims 1 to 7, wherein the lower layer liquid contains one or a mixture of two or more selected from organic halogen compounds. 9. The method for manufacturing a ceramic molded body according to any one of claims 1 to 7, wherein the lower liquid is made of mercury or a fusible metal. 10. The method for producing a ceramic molded body according to claim 9, wherein the melting point of the fusible alloy is 90°C or lower. 11. A method for producing a ceramic molded body according to any one of claims 1 to 10, which uses a colloid obtained by hydrolyzing one or more alkoxides as a starting material. 12. A ceramic molded article according to any one of claims 1 to 10, which uses as a starting material a mixture of two or more colloids obtained by hydrolyzing one or more alkoxides. Production method.