JP3316634B2 - Manufacturing method of porous ceramics - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel method for producing a porous ceramic material useful as a filter, various adsorbents, a catalyst carrier for automobile exhaust gas, a carrier for a bioreactor, a sound absorbing material, a building material and the like.

[0002]

2. Description of the Related Art The properties of porous ceramics are not only those possessed by the ceramic itself, but also the shape of the pores,
It is also caused by porosity, pore diameter, and the like. Therefore, various manufacturing methods for obtaining a ceramic porous body suitable for the use have been proposed.

[0003] As a typical method for producing a porous ceramic body having continuous pores, a method of press-forming ceramic raw material powder at a low density and firing the formed body at normal pressure to leave voids between the raw material powders as pores. It has been known. In this method, the porosity is wedge-shaped, the porosity is generally as low as 30 to 50%, and the porosity cannot be increased. Furthermore, in order to increase the pore size, the size of the raw material powder must be increased. However, this makes sintering difficult, so that there is a problem that a binder must be used.

In addition, a solid combustible such as starch, wheat flour, carbon black, and wood flour is mixed with ceramic powder as an additive, molded, fired, and the voids left after the additive is removed by combustion are removed. A method of utilizing as pores is also known. In this method, if the amount of the combustibles is small, a closed void is easily formed inside the fired body, and it is difficult to form continuous pores. In addition, when the amount of the combustible added is increased to form continuous pores, cracks are generated, so that it is difficult to obtain one having a high porosity. Furthermore, although the size of the pores is determined by the particle size of the combustible, it is relatively difficult to change the particle size because the combustible is solid, and thus it is difficult to arbitrarily adjust the size of the pores. is there.

On the other hand, a method of filling a ceramic powder slurry into the voids of a packing of spherical organic substances whose sphere surfaces are in contact with each other, removing the organic substances after drying, and firing (Japanese Patent Application Laid-Open No. 60-1985).
No. 251822) is also known. In this method, a porous body having a desired pore diameter can be obtained by appropriately selecting the particle diameter of the spherical organic substance.However, a step of filling and drying a slurry of ceramic powder and further drying the organic substance with an organic solvent In the process of dissolving and removing, or the process of thermally decomposing an organic substance by heating, there is a defect that cracks are generated in the skeleton.

Further, a method of impregnating a slurry of an inorganic powder into a foamed urethane foam or the like, coating the surface of the organic three-dimensional network structure with the slurry of the inorganic powder, and firing the same (Japanese Patent Application Laid-Open No. 55-24585). Are known. According to this method, a ceramic porous body having a high porosity of 90% can be obtained. However, it is difficult to adjust the porosity, and only a very large pore having a pore diameter of about 1 to 4 mm can be obtained. At the center of the body skeleton, there is a cavity based on an organic skeleton, which has the disadvantage that a porous body with high strength cannot be obtained.

The present inventors have previously described a novel method for producing a ceramic porous body by mixing a ceramic powder, a polymerizable unsaturated compound, an emulsifier, and water to form a water-in-oil emulsion, and then forming the emulsion in the emulsion. After polymerizing and curing the polymerizable unsaturated compound, drying and firing are performed to obtain a porous body having a small pore size and continuous pores, and a method of producing a ceramic porous body capable of easily adjusting the porosity in a wide range ( JP-A-63-270368, JP-A-2-12
No. 0285). In these methods, the pore diameter is almost 1 to 10 μm, and it is difficult to stably obtain a pore having a larger pore diameter.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a novel method for producing a porous ceramic body having no problems as described above, and an object of the present invention is to provide a porous ceramic body having a relatively large pore diameter and a continuous pore. Another object of the present invention is to provide a method for producing a porous ceramic body, in which the size and porosity of pores can be easily adjusted in a wide range.

[0009]

According to the present invention, an aqueous solution of a ceramic powder, a polymerizable unsaturated compound, an emulsifier, a radical polymerization initiator or a redox polymerization initiator, and an aqueous solution of a high molecular compound are mixed to form a water-in-oil type. Emulsion and none,
The present invention provides a method for producing a ceramic porous body, which comprises polymerizing a polymerizable unsaturated compound in the water-in-oil emulsion, followed by drying and firing.

The water-soluble polymer compound is cellulose ether or polyvinyl alcohol;
In particular, the present invention provides the method for producing a ceramic porous body, wherein the cellulose ether is at least one selected from hydroxypropylmethylcellulose, hydroxyethylcellulose, hydroxyethylmethylcellulose, and methylcellulose.

The emulsifier further comprises at least one surfactant selected from sorbitan sesquiolate, sorbitan monooleate and sorbitan monostearate;
H. L. B. Is mixed with at least one surfactant selected from phosphate esters of polyoxyethylene alkyl ethers or polyoxyethylene alkyl aryl ethers having a pH of 6.5 to 11.5. L. B. 3.
A method for producing the porous ceramic body, characterized in that the ceramic porous body is prepared to have a thickness of 5 to 6.0.

The inventors of the present invention have conducted intensive studies in view of the current situation. As a result, in a method for producing a porous ceramic body using a water-in-oil emulsion, an aqueous solution of a water-soluble polymer compound was used as a dispersion phase. The inventors have found that the object of the present invention can be achieved, and have completed the present invention. That is, in the present invention, the polymerizable unsaturated compound acts as an oil phase of the water-in-oil emulsion, and the aqueous solution of the water-soluble polymer compound is dispersed uniformly in the oil phase as water droplets as a dispersed phase. . After the polymerization, when the water in the dispersed phase is evaporated, the portion becomes pores, and thus the polymer becomes porous. When this porous polymer is fired by a usual method, pores formed by evaporating water mainly in the dispersed phase remain in the ceramic to become a porous ceramic. The present invention is based on the finding that water droplets of a water-in-oil emulsion polymer can be enlarged by using an aqueous solution of a water-soluble polymer compound, more preferably in combination with a special surfactant. is there.

As the ceramic powder used in the present invention, those which are sinterable and do not cause remarkable phase separation of a water-in-oil emulsion can be used. For example, alumina, zirconia, magnesia, spinel, zinc oxide, Metal oxides such as iron oxide, titanium oxide, and tin oxide; metal hydroxides such as aluminum hydroxide, magnesium hydroxide, and calcium hydroxide; and silicon carbide, silicon nitride, and aluminum nitride. However, the present invention is not limited to this. These can be used alone or in combination of two or more. In addition, calcium oxide, magnesium oxide, yttrium oxide,
Sintering aids such as cerium oxide, lithium oxide, borates and silicates, binders such as vitreous flux, and other coloring agents may be appropriately added in small amounts.

As the polymerizable unsaturated compound used in the present invention, those capable of undergoing radical polymerization or redox polymerization and capable of forming a water-in-oil emulsion can be used. For example, styrene, α-methyl Styrene, styrenes such as divinylbenzene, methacrylates such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, and methacrylic acid, methyl acrylate, ethyl acrylate,
Acrylic esters and acrylic acids such as butyl acrylate, 2-ethylhexyl acrylate, ethylene glycol diacrylate, and trimethylolpropane triacrylate, as well as vinyl acetate, diallyl phthalate, acrylonitrile, methacrylonitrile, and unsaturated polyesters. But not limited thereto. These can be used alone or in combination of two or more. Particularly, polymerizable polyfunctional unsaturated compounds such as divinylbenzene, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, ethylene glycol diacrylate, trimethylolpropane triacrylate, epoxy (meth) acrylate, polyester (meth) acrylate, It is more preferable that urethane (meth) acrylate, diallyl phthalate, unsaturated polyesters and the like be mixed with a polymerizable monofunctional unsaturated compound and copolymerized, since the polymer has a crosslinked structure.

Examples of the water-soluble polymer compound in the present invention include cellulose ethers such as hydroxypropylmethylcellulose, hydroxyethylcellulose, hydroxyethylmethylcellulose, methylcellulose and sodium carboxymethylcellulose; synthetic polymer compounds such as polyvinyl alcohol, polyethylene oxide and polyvinylpyrrolidone; Examples include natural polymer compounds such as starch, gum arabic, and gelatin.

These water-soluble polymer compounds change the size of water droplets as a dispersed phase mainly due to a thickening action and a surfactant action on the dispersed phase in the formation of a water-in-oil emulsion. Conceivable. The type of the water-soluble polymer compound and the concentration of the aqueous solution are very closely related to the size of the water droplet in the water-in-oil emulsion, and as the concentration of the aqueous solution of the water-soluble polymer compound increases, the size of the water droplet increases. The pore size of the obtained porous ceramic body also increases. Therefore, by appropriately selecting the type of the aqueous polymer compound and the concentration of the aqueous solution, a water-in-oil emulsion polymer having a desired pore size can be obtained, and a porous polymer obtained therefrom can be obtained. By firing, a ceramic porous body having a desired pore size is obtained.

The concentration of the aqueous solution of the water-soluble polymer compound is selected so as to obtain a thickening action and a surface-active action sufficient to form a water-in-oil emulsion having large water droplets. In order to obtain the strength of the emulsion polymer,
The concentration is desirably 0.05 to 20% by weight. In addition, among the water-soluble polymer compounds used in the present invention, hydroxypropylmethylcellulose, hydroxyethylcellulose, hydroxyethylmethylcellulose, cellulose ethers such as methylcellulose, and polyvinyl alcohol have an effect of increasing water droplets that are a dispersed phase even at a low concentration. It is particularly preferred because it has

The emulsifier used in the present invention is not particularly limited as long as it has an action of producing a water-in-oil emulsion. L. B. Are suitable, for example, higher fatty acid esters of sorbitan such as sorbitan sesquiolate, sorbitan monooleate, sorbitan monostearate, glycerol stearate, and polyglycerol oleate. And higher fatty acid esters of glycerol. These emulsifiers may be used as a mixture of two or more kinds in order to obtain a desired effect. In addition, these surfactants,
H. L. B. Surfactants, such as polyoxyethylene nonyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene alkyl phenyl ether such as polyoxyethylene octyl phenyl ether, polyoxyethylene oleyl ether, polyoxyethylene lauryl ether and the like Nonionic surfactants such as fatty acid esters of polyoxyethylene such as polyoxyethylene alkyl ether and polyoxyethylene oleate, and phosphorus of polyoxyethylene alkyl ether such as polyoxyethylene lauryl ether and polyoxyethylene tridecyl ether Acid esters, polyoxyethylene nonyl phenyl ether, polyoxyethylene dinonyl phenyl ether, and other polyoxyethylene alkyls Mixing the like anionic surfactants such as phosphoric acid ester of phenyl ether with H. L. B. Adjusted to about 3.5 to 6.0 can also be used.

In the present invention, since the emulsifier interacts with the water-soluble polymer compound in the dispersed phase, the type of emulsifier and H.I. L. B. By appropriately selecting the value of
The size of the pores can also be varied. In particular, at least one surfactant selected from sorbitan sesquiolate, sorbitan monooleate, and sorbitan monostearate; L. B. Is mixed with at least one surfactant selected from phosphate esters of polyoxyethylene alkyl ethers or polyoxyethylene alkyl aryl ethers having a pH of 6.5 to 11.5. L.
B. Is preferably adjusted to about 3.5 to 6.0 because the pore size can be easily changed in a wide range. The ratio of the emulsifier to the polymerizable unsaturated compound is
The amount is preferably 5 to 50 parts by weight, more preferably 10 to 20 parts by weight, based on 100 parts by weight of the polymerizable unsaturated compound.

As a radical polymerization initiator or a redox polymerization initiator, a conventional radical polymerization initiator or a redox polymerization initiator can be used, but remarkable phase separation of a water-in-oil emulsion and evaporation of water are avoided. Therefore, it is selected from those having a function as a polymerization initiator at 100 ° C. or lower. Examples include hydrogen peroxide, ammonium persulfate, potassium persulfate, benzoyl peroxide, lauroyl peroxide, t-butyl peroxyoctoate, p-menthane hydroperoxide, simiristil peroxydicarbonate, 1,1-bis Peroxide-based polymerization initiators such as (t-butylperoxy) cyclohexane, azo-based polymerization initiators such as azobisisobutyronitrile and azobis-2,4-dimethylvaleronitrile, cumene hydroperoxide / polyamine.Fe (II) salt, hydrogen peroxide / ethylamine / Fe (II) salt, ammonium persulfate / potassium persulfate / sodium sulfite / sodium bisulfite / triethanolamine / Fe (II) salt, benzoyl peroxide / lauroyl peroxide / methyl ethyl ketone Peroxide / t-butyl hydropa It can be used redox polymerization initiator by combination of such oxide / dimethyl aniline naphthenate cobalt sulfinic acid. The addition amount of the polymerization initiator is preferably 0.05 to 5 parts by weight based on 100 parts by weight of the polymerizable unsaturated compound.

With respect to the composition in the water-in-oil emulsion, the weight ratio of the ceramic powder, the polymerizable unsaturated compound, and the water-soluble polymer compound is 100: 10 to 50:
10 to 300 is desirable. The water-in-oil emulsion obtained at this composition ratio is stable, the polymer has an appropriate strength, and the deformation of the fired product is small. More preferably,
100: 20 to 40:30 to 200. The amount of the aqueous solution of the water-soluble polymer compound is extremely closely related to the porosity and pore size of the water-in-oil emulsion porous polymer and the ceramic porous body obtained by firing the polymer. That is, the porosity increases as the ratio of the aqueous solution of the water-soluble polymer compound increases, and conversely, the porosity decreases as the ratio decreases. Also, when the ratio of the aqueous solution of the water-soluble polymer compound is increased, the size of the pores of the porous polymer or the ceramic porous body obtained by baking it is increased,
Conversely, as the ratio decreases, the size of the pores decreases.

The smaller the composition ratio of the polymerizable unsaturated compound is, the easier the baking is. However, if the composition ratio is too small, it becomes difficult to form a water-in-oil emulsion or the strength of the polymer is reduced. On the other hand, if the composition ratio of the polymerizable unsaturated compound is too large, deformation or the like occurs during firing, which is not preferable.

Next, the manufacturing method will be described. In the present invention, first, ceramic powder, polymerized unsaturated compound, emulsifier, radical polymerization initiator or redox polymerization initiator,
An aqueous solution of a water-soluble polymer compound is mixed to form a water-in-oil emulsion. For example, the method is as follows: a ceramic powder and an emulsifier are mixed in advance with a polymerizable unsaturated compound, and then the water-soluble polymer is mixed. A method of stirring while adding an aqueous solution of a compound or stirring after addition. A method in which an aqueous solution of a polymerizable unsaturated compound, an emulsifier, and a water-soluble polymer compound is mixed in advance to form a water-in-oil emulsion, and then the mixture is stirred while ceramic powder is added, or stirred after addition. A method in which a ceramic powder, a polymerizable unsaturated compound, an emulsifier, and an aqueous solution of a water-soluble polymer compound are simultaneously added, followed by mixing and stirring. However, as long as a water-in-oil emulsion is formed, the present invention is not limited thereto. The polymerization initiator is previously dissolved in a polymerizable unsaturated compound or an aqueous solution,
If it dissolves in the oil phase, it may be added and dissolved later.

For mixing and stirring, a stirrer having blades such as a paddle cross, a propeller, and a turbine, a mixer such as a ball mill and a colloid mill, a kneader, a pony mixer,
A kneader such as a screw extruder can be used, but is not limited thereto as long as a water-in-oil emulsion is formed. The polymerization temperature and polymerization time are set at 10 to avoid remarkable phase separation of the water-in-oil emulsion and evaporation of water.
It is preferable to set the temperature at 0 ° C. or lower for 1 to 48 hours. In these processes, the polymerizable unsaturated compound acts as the oil phase of the water-in-oil emulsion, but since the ceramic powder is in the oil phase, it also acts as a binder for the ceramic powder after polymerization. Have. The aqueous solution of the water-soluble polymer compound is uniformly dispersed in the oil phase as small droplets. After the polymerization, when the polymer is dried and water is evaporated, the portion becomes a pore and the polymer becomes porous. At that time, the water-soluble polymer compound remains in the pores. Examples of the drying method include hot air drying, internal heating drying, vacuum drying, and freeze drying. The polymer obtained by drying has an appropriate strength and can be cut.

When the porous polymer is calcined by an ordinary method, first, a polymer of an organic polymerizable unsaturated compound, a water-soluble polymer compound, an emulsifier and the like are removed by thermal decomposition or oxidative decomposition. The ceramic powder existing in the oil phase remains while maintaining the porous skeleton, and then the ceramic powder is sintered or bonded to obtain a ceramic porous body. The firing is preferably performed at a temperature rising rate of 1 to 200 ° C./hr and at a temperature of 1000 ° C. or higher. The firing conditions are
Optimum depending on the type and particle size of the ceramic powder, polymerizable unsaturated compound, water-soluble polymer compound, and the type of emulsifier and their composition ratio, polymer size and shape, furnace atmosphere, etc. May be appropriately selected as described above.
In particular, in a temperature range in which thermal decomposition or oxidative decomposition of organic substances occurs, it is preferable to perform calcination at a low humidification rate in order to prevent deformation and cracks of the porous skeleton. At that time, if the polymer has a structure cross-linked by a polymerizable polyfunctional unsaturated compound, the porous skeleton may be deformed or cracked even if the heating rate in this temperature range is increased. Since it is difficult, the energy for firing is small and the cost is low, so that it is preferable.

In the present invention, since the pores in the polymer are based on water droplets of an aqueous solution which is a dispersed phase, they are substantially spherical and uniformly distributed. The size of the pores in the polymer is
It has a large pore diameter of about 10 μm to about 500 μm, and some smaller ones are mixed in the polymer. When these are fired, the ceramic powder is present in the oil phase, so that the pores formed in the ceramic are almost spherical. However, when the pores in the polymer are close to each other and the cell walls of the pores are thin or the ceramic powder is large, the fusion of the pores may occur by firing. The size of the pores in the ceramics is also large with a large pore diameter of about 10 μm to about 500 μm, and smaller ones are mixed in the ceramics. In addition, these pores are continuous pores, which are formed mainly by voids generated between the ceramic powders due to removal of organic substances in the oil phase and fusion of the pores.

Hereinafter, the present invention will be described in more detail by way of examples.
I will tell. In addition, the continuous obtained in the Example and the Comparative Example
For porous ceramics with pores,
Measurement of pore diameter, apparent porosity and bulk specific gravity
Done. Pore size: Large from the scanning electron micrograph of the fractured surface of the fired body
Measure the average size of the pores. W₁: Dry weight of test piece (g) Drying temperature 105 ° C W_Two: Saturated weight of test piece (g) After boiling for 3 hours, cool
After taking out from the water, remove the water droplets on the surface
Weight W_Three： Water weight of saturated water sample (g)

[0029]

【Example】

Example 1 100 parts by weight of alumina (AES-11, manufactured by Sumitomo Chemical Co., Ltd.), 21.6 parts by weight of styrene, 2.4 parts by weight of trimethylolpropane trimethacrylate (hereinafter abbreviated as TMPT), sorbitan sesquiolate ( H.L.B. = 3.
7, Rheodol AO-15, manufactured by Kao Corporation) was charged into a ball mill and mixed for 24 hours to obtain 130 parts by weight of a mixture. 130 parts by weight of the obtained mixture was transferred to a polyethylene container, and 60 parts by weight of a 2% by weight aqueous solution of hydroxypropyl methylcellulose (Metroze 90SH-4000, manufactured by Shin-Etsu Chemical Co., Ltd.) in which 0.12 part by weight of ammonium persulfate was dissolved was gradually added. The mixture was vigorously stirred with a paddle-shaped stirring blade to obtain a stable water-in-oil emulsion. Next, the obtained water-in-oil emulsion was poured into a mold, polymerized at 60 ° C. for 24 hours, and then demolded.
It dried at ℃ and obtained the porous polymer. This porous weight was fired in air at a temperature rising rate of 50 ° C./hr and 1350 ° C. to obtain a porous ceramic body having continuous pores. Table 1 shows the properties of the obtained ceramic porous body.

Comparative Example 1 A porous ceramic body having continuous pores was obtained in the same manner as in Example 1 except that water was used instead of the aqueous solution of the water-soluble polymer compound as the dispersed phase. The pore size of the obtained porous body was 5 μm, which was smaller than that using a hydroxypropylmethylcellulose aqueous solution as the dispersed phase (Example 1). Table 1 shows other characteristics.

In Examples 2 and 3, ceramic porous bodies having continuous pores were prepared by changing the type of the water-soluble polymer compound.

Example 2 100 parts by weight of alumina (AES-11), styrene 2
6.7 parts by weight, 3 parts by weight of divinylbenzene, 5.3 parts by weight of sorbitan sesquiolate were charged into a ball mill,
After mixing for 4 hours, 135 parts by weight of the mixture was obtained. 135 parts by weight of the obtained mixture was transferred to a polyethylene container, and 0.15 parts by weight of ammonium persulfate was dissolved in 2% by weight of hydroxyethyl cellulose (HEC Daicel S).
While slowly adding 100 parts by weight of an aqueous solution (P600, manufactured by Daicel Chemical Industries, Ltd.), the mixture was vigorously stirred with a paddle cross stirrer to obtain a stable water-in-oil emulsion. Thereafter, a porous ceramic body having continuous pores was obtained in the same manner as in Example 1.
Table 1 shows the properties of the obtained ceramic porous body.

Example 3 Alumina (AES-22S, manufactured by Sumitomo Chemical Co., Ltd.) 100
Parts by weight, 26.5 parts by weight of styrene, 3 parts by weight of TMPT,
Phosphoric acid ester of 4.5 parts by weight of sorbitan sesquiolate and polyoxyethylene nonyl phenyl ether (H.
L. B. = 10.3) 1 part by weight and mixing L. B.
Was added to a ball mill, and the mixture was mixed for 24 hours to obtain 135 parts by weight of the mixture.
135 parts by weight of the obtained mixture was transferred to a polyethylene container, and 0.15 parts by weight of ammonium persulfate was dissolved therein.
While slowly adding 60 parts by weight of a weight percent aqueous solution of polyvinyl alcohol (Shin-Etsu Bovar PA-18, manufactured by Shin-Etsu Chemical Co., Ltd.), the mixture was vigorously stirred with a paddle-shaped stirring blade to obtain a stable water-in-oil emulsion. Hereinafter, a ceramic porous body having continuous pores was obtained in the same manner as in Example 1 except that the firing conditions were changed to a heating rate of 20 ° C./hr and 1450 ° C. Table 1 shows the properties of the obtained ceramic porous body.

Comparative Example 2 A porous ceramic body having continuous pores was obtained in the same manner as in Example 3 except that water was used as the dispersed phase instead of the aqueous solution of the water-soluble polymer compound. The obtained porous body had a pore size of 4 μm, and showed no interaction with the emulsifier, and the pore size was smaller than that of Example 3. Table 1 shows other characteristics.

In Examples 4 and 5, ceramic porous bodies having continuous pores having different pore diameters were prepared by changing the amount of the aqueous solution of the water-soluble polymer compound.

Example 4 100 parts by weight of alumina (ALM-25, manufactured by Sumitomo Chemical Co., Ltd.), 23.4 parts by weight of styrene, 2.6 parts by weight of TMPT, 3 parts by weight of sorbitan sesquiolate and phosphorus of polyoxyethylene nonylphenyl ether 1 part by weight of the acid ester was mixed and mixed. L. B. Mixture 4 adjusted to 5.4
Parts by weight were put into a ball mill and mixed for 24 hours to obtain 130 parts by weight of the mixture. 130 parts by weight of the obtained mixture was transferred to a polyethylene container, and 0.1% of ammonium persulfate was added.
While gradually adding 100 parts by weight of a 0.5 part by weight aqueous solution of hydroxypropylmethyl cellulose in which 3 parts by weight was dissolved, the mixture was vigorously stirred with a paddle-shaped stirring blade to obtain a stable water-in-oil emulsion. Hereinafter, a ceramic porous body having continuous pores was obtained in the same manner as in Example 1 except that the firing conditions were changed to a heating rate of 30 ° C./hr and 1550 ° C. Table 1 shows the properties of the obtained ceramic porous body.

Example 5 A ceramic porous body having continuous pores was obtained in the same manner as in Example 4, except that the aqueous solution of 0.5% by weight of hydroxypropylmethylcellulose was changed to 150 parts by weight.
Table 1 shows the properties of the obtained ceramic porous body.

Example 6 100 parts by weight of alumina (AES-11), styrene 16
Parts by weight, sorbitan monooleate (HLB = 4.
3.4 Reodol SP-O10, manufactured by Kao Corporation) and 0.6 part by weight of a phosphoric acid ester of polyoxyethylene nonylphenyl ether. L. B. 5.2
4 parts by weight of the mixture adjusted to
The mixture was mixed for 120 hours to obtain 120 parts by weight of the mixture. 120 parts by weight of the obtained mixture was transferred to a polyethylene container, and 0.5% by weight of an aqueous solution of hydroxypropylmethylcellulose 5 containing 0.16 parts by weight of ammonium persulfate was dissolved.
The mixture was vigorously stirred with a paddle-shaped stirring blade while gradually adding 0 parts by weight to obtain a stable water-in-oil emulsion. Hereinafter, a ceramic porous body having continuous pores was obtained in the same manner as in Example 1 except that the firing conditions were changed to a heating rate of 5 ° C./hr. Table 1 shows the properties of the obtained ceramic porous body.

Example 7 The emulsifier was sorbitan monostearate (HLB =
4.7 Sorgen 50 (Daiichi Kogyo Seiyaku) 3.4 parts by weight and 0.6 parts by weight of a polyoxyethylene nonylphenyl ether phosphate ester were mixed. L. B. To 5.
Example 6 except that 4 parts by weight of the mixture adjusted to 5 were used.
In the same manner as in the above, a ceramic porous body having continuous pores was obtained. Table 1 shows the properties of the obtained ceramic porous body.

In Examples 8 to 10, the emulsifier H.I. L.
B. Instead, a ceramic porous body having continuous pores having different pore diameters was prepared.

Example 8 100 parts by weight of alumina (AMS-5, manufactured by Sumitomo Chemical Co., Ltd.), 24.3 parts by weight of styrene, 2.7 parts by weight of TMPT, 2.3 parts by weight of sorbitan sesquiolate and polyoxyethylene tridecyl Phosphates of ethers (H.
L. B. = 11.5) 0.7 parts by weight, and L.
B. Was added to a ball mill and mixed for 24 hours to obtain 130 parts by weight of the mixture.
130 parts by weight of the obtained mixture was transferred to a polyethylene container, and while gradually adding 100 parts by weight of a 0.4% by weight aqueous solution of hydroxypropylmethylcellulose in which 0.14 parts by weight of ammonium persulfate was dissolved, a paddle-shaped stirring blade was used. The mixture was vigorously stirred to obtain a stable water-in-oil emulsion. Hereinafter, the sintering conditions were as follows: heating rate 30 ° C./hr,
A ceramic porous body having continuous pores was obtained in the same manner as in Example 1 except that the temperature was changed to 50 ° C. Table 1 shows the properties of the obtained ceramic porous body.

Example 9 2.3 parts by weight of sorbitan sesquiolate and 0.7 part by weight of a phosphoric acid ester of polyoxyethylene tridecyl ether (HLB = 9.4) were mixed as an emulsifier, and
L. B. Was changed to 5.0, and a ceramic porous body having continuous pores was obtained in the same manner as in Example 8, except that 3 parts by weight of the mixture was adjusted to 5.0. Table 1 shows the properties of the obtained ceramic porous body.

Example 10 As an emulsifier, 2.3 parts by weight of sorbitan sesquiolate and 0.7 part by weight of a phosphoric acid ester of polyoxyethylene lauryl ether (HLB = 6.6) were mixed.
L. B. Was changed to 4.4, and a ceramic porous body having continuous pores was obtained in the same manner as in Example 9 except that the mixture was changed to 4.4 parts by weight. Table 1 shows the properties of the obtained ceramic porous body.

[0045]

[Table 1]

[0046]

According to the present invention, a method for producing a porous ceramic body using a water-in-oil emulsion is characterized in that an aqueous solution of a water-soluble polymer compound is used as a dispersion phase in the emulsion. In the porous ceramic body obtained by the production method of the present invention, pores are uniformly distributed, and the shape thereof is substantially spherical. The size of the pores is from a few tens of μm to about 500 μm with a large pore size, and smaller ones are also mixed, and the size and porosity of these pores are determined by the concentration of the aqueous solution of the water-soluble polymer compound. ,
It can be easily adjusted to an arbitrary size depending on the amount added. Further, these pores are continuous pores due to voids between the ceramic powders and fusion of the pores. The ceramic porous body obtained by the present invention is useful for filters, various adsorbents, catalyst carriers, carriers for bioreactors, sound-absorbing materials, building materials, etc. by making use of its features.

[Brief description of the drawings]

FIG. 1 is an electron micrograph of a ceramic porous body manufactured in Example 4.

Claims (4)

(57) [Claims] An aqueous solution of a ceramic powder, a polymerizable unsaturated compound, an emulsifier, a radical polymerization initiator or a redox polymerization initiator, and a water-soluble polymer compound is mixed to form a water-in-oil emulsion. A method for producing a ceramic porous body, comprising: polymerizing a polymerizable unsaturated compound in an emulsion, followed by drying and firing. 2. The production of a porous ceramic body according to claim 1, wherein said water-soluble polymer compound is at least one selected from hydroxypropylmethylcellulose, hydroxyethylcellulose, hydroxyethylmethylcellulose, methylcellulose and polyvinyl alcohol. Method. 3. The method according to claim 1, wherein the emulsifier comprises at least one surfactant selected from sorbitan sesquiolate, sorbitan monooleate and sorbitan monostearate.
L. B. at least one surfactant selected from phosphate esters of polyoxyethylene alkyl ether or polyoxyethylene alkyl aryl ether having 6.5 to 11.5, L. B to 3.5-6.
The method for producing a porous ceramic body according to claim 1, wherein the ceramic porous body is adjusted to 0. 4. The ceramic porous body according to claim 1, wherein the polymerizable unsaturated compound is a mixture of a polymerizable monofunctional unsaturated compound and a polymerizable polyfunctional unsaturated compound. Manufacturing method.