JP2002274954A - Granule for forming ceramic, formed body, sintered compact and electronic part using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide granules for forming ceramics from which a ceramic formed body or sintered compact having high bending strength and little chipping, cracks and fracture can be formed. SOLUTION: The granules for forming ceramics consists of 100 parts by mass of the source powder of ceramics, 0.4 to 1.4 parts by mmass of polyvinyl alcohol having 500 to 1,700 average polymerization degree and >=88 mol% average saponification degree, and 0.4 to 1.4 parts by mass of a water dispersion type phenol resin having 0.5 to 3 μm average particle size.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to ceramic molding granules, ceramic moldings, ceramic sinters, and electronic components using these. More specifically, a high-quality ceramic molding that can provide a high-strength ceramic molding that can be used for the manufacture of a wide range of electronic components and a ceramic sintered body that has few appearance defects such as chips, cracks, and breaks. The present invention relates to granules for use, ceramic molded bodies and sintered ceramics using the same, and electronic components using the same.

[0002]

2. Description of the Related Art Ceramics are widely used for various electronic components. Such ceramics are generally formed by molding ceramic molding granules composed of ceramic raw material powder and a binder into various shapes according to the purpose as shown in FIGS. 1 and 2, for example. Obtained by sintering. Ceramic products obtained in this manner can be used for information terminals such as notebook computers, PDAs and the like, mobile phones such as mobile phones, PHSs and the like, or portable electronic products such as peripheral devices, televisions and stereos. Are used for various electronic parts such as relatively large home appliances, and the ceramic sintered bodies used for these tend to be further reduced in size, thickness and weight. Therefore, small or thin and highly durable ceramics used for these electronic product parts are desired.

Hitherto, various methods have been employed for producing a ceramic molded body from granules for ceramic molding, and among them, a dry pressure molding method is generally widely used. For example, an aqueous slurry is prepared from a ceramic raw material powder, a binder, and water, and the resulting slurry is spray-dried with a spray dryer, or granules produced by mixing and mixing the ceramic raw material powder and a binder solution, followed by drying and oscillating extrusion granulation. By pressing the granules produced by repeating the above steps, a ceramic molded body is manufactured. The formed body thus manufactured is processed as necessary, and then subjected to the steps of degreasing, firing at a predetermined temperature, and processing to obtain a ceramic sintered body as a final product.

[0004] As a binder component added at this time,
Polyvinyl alcohol (PVA), polyacrylic resin, cellulose resin and the like are generally used, and the binder component is usually 1 to 100 parts by mass of the raw material powder.
10 parts by weight are added. In a ceramic molded article obtained by molding granules for ceramic molding spray-granulated by spray drying using a binder represented by polyvinyl alcohol, the bending strength by ordinary three-point bending is as follows.
It is about 1.0 to 2.0 MPa. However, for example, a ceramic molded body is formed into a core mold as shown in FIGS. 1 (a) to 1 (c), or FIGS. 2 (a) and 2 (b).
As shown in the figure, a ceramic molded body is molded into a plate shape,
At this time, in the case of a core type, for example, the core is often formed to have a diameter of 2 mm or less, and in the case of a plate type, the thickness is often formed to about 1 mm.

In such a case, the transverse rupture strength is 1.0-2.
If it is about 0 MPa, it may be damaged or cracked during handling. Therefore, there is a demand for granules for ceramic molding capable of molding a ceramic molded body having a bending strength of 2.0 MPa or more, preferably 2.5 MPa or more.

In order to increase the strength of such a compact,
It is generally effective to increase the amount of the binder at the time of granulation, but simply increasing the amount of the binder extends the degreasing time or decreases the density of the sintered body obtained by firing, In addition, since the size control becomes difficult due to the increase in firing shrinkage, the amount of the binder to be added is naturally limited.

As another method for improving the strength of a compact, a method of adjusting the water content of granules containing a binder can be considered. Such moisture adjustment has been mainly used to improve the moldability, that is, to facilitate the deformation of the granulated powder during pressurization,
It is performed to remove defects in the molded body due to deformation. For example, in Japanese Patent Publication No. 6-8201, the water content is 1.5 to 7 parts by mass with respect to 100 parts by mass of the granulated powder. Adjustment is described.

However, when the water content in the ceramic molding granules is generally 1.0% by mass or more, so-called sticking that the ceramic fine powder adheres to the mold is liable to occur. It is known that this may cause trouble during molding. As described above, attempts have been made to improve the bending strength of the ceramic molded body obtained by adjusting the amount of the binder and the amount of water in the ceramic molding granules. Could not be obtained.

Further, as another method for obtaining a ceramic molded body having high bending strength, for example, Japanese Patent Application Laid-Open No. 10-25 / 1998
No. 9060 proposes that granules obtained by spray granulation of a ceramic slurry based on an organic solvent such as isopropanol containing a phenol resin as a binder are subjected to heat treatment after CIP molding. According to this method, the binder containing 50% by mass or more of the phenol resin is 3 to
Although 30% by mass is added, if such a large amount of binder is added, it is necessary to perform degreasing for a long time as described above, and the product density after firing decreases, and further, dimensional control becomes difficult, and as a result, The disadvantage is that the dimensional accuracy of the formed ceramic body is reduced. Further, the use of an organic solvent typified by flammable isopropyl alcohol requires explosion-proof equipment in the manufacturing equipment, and causes environmental health problems.

[0010]

Therefore, there is a strong demand for a ceramic molding granule which is a water-based binder, and which can provide a high bending strength to the obtained ceramic molded body with as little binder and water content as possible. There is. Therefore, an object of the present invention is to provide ceramic molding granules which can give a high bending strength to the obtained ceramic molding with a relatively small amount of binder and water. Another object of the present invention is to provide a ceramic molded body having high bending strength, preferably 2.5 MPa or more. Still another object of the present invention is a chip obtained by firing a ceramic molded body having such high bending strength,
An object of the present invention is to provide a ceramic sintered body having less appearance defects such as cracks and breaks.

[0011]

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, as a binder used when granulating ceramics forming granules, a specific polyvinyl alcohol and an aqueous dispersion type binder were used. The present inventors have found that the above-mentioned problems can be solved by using a phenol resin in a predetermined ratio, and have led to the creation of the present invention. That is, a first embodiment of the present invention is a granule for forming a ceramic obtained by granulating a mixture of a ceramic raw material powder and a binder, the ceramic raw material powder having an average degree of polymerization of 100 parts by mass.
00 to 1700, 0.4 to 1.4 parts by mass of polyvinyl alcohol having an average saponification degree of 88 mol% or more, and 0.4 to 1. 1 of a water-dispersible phenol resin having an average particle size of 0.5 to 3 μm.
It is a granule for forming ceramics, comprising 4 parts by mass (claim 1). With this configuration, it is possible to obtain ceramic molding granules capable of providing a high-strength ceramic molding. Moreover, the granules for ceramic molding of the first embodiment are granulated from an aqueous slurry of ceramic raw material powder, a specific polyvinyl alcohol, and a specific water-dispersed phenol resin, so that additional equipment such as explosion-proof equipment is required. None, and is preferable in environmental hygiene.

[0012] In the ceramic molding granules according to the first aspect, the polyvinyl alcohol has an average saponification degree of 94.
It is preferably from 5 to 97.5 mol%. Ceramic molding granules obtained by using polyvinyl alcohol having an average degree of saponification within the above range are granules having a good balance of low pressure crushing property and collapse resistance and sticking resistance, and dimensional variation using this. Thus, a good ceramic molded body and a ceramic sintered body with a small amount are obtained. In addition, the term “low pressure crushing property” used in the present invention refers to a low pressure (typically 29 to 1) when forming a mold.
47 MPa) means that the film is uniformly crushed. Also,
"Disintegration resistance" means that granules for ceramic molding do not collapse due to rolling or mutual collision during storage, transportation, or filling in a mold. Further, "sticking resistance" means that components such as fine particles in ceramic molding granules do not adhere to a mold or the like.

A second aspect of the present invention relates to a ceramic molded body obtained by dry-press-molding the ceramic molding granules of the first aspect (claim 3). The ceramic molded body thus obtained has a bending strength of 2.0M.
It has a high strength of Pa or more, preferably 2.5 MPa or more. Therefore, the occurrence of breakage and cracks during handling is reduced, and a high-density ceramic sintered body as a final product can be manufactured with high dimensional stability.

A third embodiment of the present invention relates to a ceramic sintered body obtained by firing the ceramic molded body of the second embodiment. The ceramic sintered body thus obtained has high density and high dimensional stability with few chips and cracks.

In the third aspect of the present invention, the ceramic sintered body having such high density and high dimensional stability has a core shape having a diameter of 2 mm or less or a thickness of 1 m.
m (plate). Such a relatively thin core and a relatively thin core sufficiently meet the requirements for reducing the size and weight of electronic components. Further, it is possible to obtain a final ceramic product having a small size and a complicated shape.

A fourth aspect of the present invention relates to an electronic component including the ceramic sintered body of the third aspect (claim 7). Such a high-density ceramic sintered body having high dimensional accuracy can be suitably used for various electronic components.

A fifth aspect of the present invention is a method for producing ceramic molding granules for molding into a ceramic molding having high strength, comprising 100 parts by mass of a ceramic raw material powder and an average degree of polymerization of 500 to 1700. A polyvinyl alcohol having an average saponification degree of 88 mol% or more,
1.4 parts by mass, 0.4 to 1.4 parts by mass of a water-dispersible phenol resin having an average particle size of 0.5 to 3 μm, and 25 to 100 parts of water
A method for producing ceramic molding granules, comprising preparing an aqueous ceramic slurry containing parts by mass, and granulating the aqueous ceramic slurry thus formed into granules for ceramic molding by a spray drying method. Item 8). With this configuration,
Unlike the case of the organic solvent-based ceramic slurry, it is possible to easily produce ceramic molding granules capable of molding a high-strength ceramic molded body without taking explosion-proof measures.

[0018]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings as needed. [Ceramics Powder] The ceramic molding granules of the present invention are composed of ceramic particles and a binder in the same manner as the conventional ceramic molding granules. The ceramic particles used at this time are appropriately selected according to the use of the ceramic sintered body to be finally sintered, and are not particularly limited. Typically, ferrite, alumina, metal oxide ceramics such as zirconia, silicon carbide,
Examples include powders of non-oxide ceramics such as silicon nitride, barium titanate, titanium / zirconate, and composite compounds thereof. These ceramic powders
They may be used alone or as a mixture of two or more. In addition, the obtained granules for forming ceramics may be a mixture of granules composed of different ceramic powders. Also, the particle size of these ceramic powders can be in the range conventionally used as a raw material of a ceramic sintered body as a final product, and is generally 0.5 to 5 μm, preferably 0.7 to 3 μm. Range.

The first essential component, polyvinyl alcohol, functions as a binder for the primary particles, that is, a binder between the raw material powder and the raw material powder. It affects the strength. In particular, the average degree of saponification of polyvinyl alcohol affects the moldability of a ceramic molded body. It is essential that the average degree of saponification of the polyvinyl alcohol used in the present invention is 88 mol% or more. That is, when a partially saponified polyvinyl alcohol having an average degree of saponification of less than 88 mol% is used as a binder component, the granules have good low-pressure crushing properties and poor disintegration resistance and sticking resistance. In addition, it has good solubility in water and its slurry preparation is simple and suitable for spray granulation. However, during oscillating extrusion granulation, the material adheres to a wire mesh and continuous granulation becomes difficult. Conversely, when the average saponification degree of polyvinyl alcohol is high, the collapse resistance is good, but the granulated ceramic molding granules are relatively hard, so the low-pressure crushability may be poor, and furthermore, the Poor solubility,
Slurry preparation may be difficult. Therefore, the average saponification degree of polyvinyl alcohol, which is the first essential component of the present invention, is preferably 94.5 to 97.5 mol%. In addition, it is preferable to use polyvinyl alcohol having an average saponification degree alone within the above range, but it is also possible to blend polyvinyl alcohols having different saponification degrees to make the average saponification degree as a whole within the above range. .

It is essential that the average degree of polymerization of the polyvinyl alcohol used in the present invention is in the range of 500 to 1700. That is, if the average degree of polymerization of polyvinyl alcohol is less than 500, the crushing properties of the granules are good, but the collapse resistance is poor, and the strength of the obtained ceramic molded body is also undesirably low. Conversely, when the average degree of polymerization of polyvinyl alcohol exceeds 1700, the collapse resistance of the granules and the strength of the obtained ceramic molded body are relatively good, but the granules for ceramic molding are too hard and the low-pressure crushing property is deteriorated. Not preferred.

The above-mentioned specific polyvinyl alcohol is used in an amount of 0.4-1.
It is added in the range of 4 parts by mass. If the amount of the polyvinyl alcohol is less than 0.4 parts by mass, it is not preferable because granules for ceramics molding cannot be granulated. Conversely, if it exceeds 1.4 parts by mass, the obtained granules for ceramics molding become too hard, It is not preferable because the crushing property is deteriorated, and as a result, a large number of granule boundaries are left and molding defects are likely to occur.

The water-dispersible phenol resin, which is the second essential component, is a phenol-based resin having the following structure:
A phenolic resin into which an ionomer component such as a polyurethane ionomer resin, a polyester ionomer resin, and a polyethylene ionomer resin is introduced, particularly a phenol formaldehyde resin, and the action of the ionomer component thus introduced into the resin. Is a resin having water dispersibility. Such a water-dispersible phenol resin is disclosed, for example, in JP-A-61-250024 and JP-A-6-250024.
No. 0-215015, JP-A-08-02735, and the like, and for example, a resin sold by Dainippon Ink and Chemicals, Inc. under the trade name of Phenolite PE series can be used. Such a water-dispersible phenolic resin can be mixed with an aqueous solution of the above-mentioned specific polyvinyl alcohol, and can be used without impairing the properties of the above-mentioned polyvinyl alcohol, and obtained. It has been found that high heat treatment of the ceramic molded body is possible by heat treatment of the granules.

The average particle size of the water-dispersible phenol resin used in the present invention must be 0.5 to 3 μm in consideration of the dispersibility with the aqueous polyvinyl alcohol solution. The amount of the water-dispersed phenolic resin is 0.4 to 100 parts by mass of the ceramic raw material.
It is in the range of 1.4 parts by mass. If the addition amount is less than 0.4 parts by mass, it is not preferable because sufficient strength cannot be given to the ceramic molded body, and conversely, the addition amount is 1.4.
Exceeding the parts by mass is not preferred because the water dispersibility of the phenol resin deteriorates and the phenol resin may remain without being thermally decomposed in the final product.

[Optional Components] In the present invention, when granulating the ceramic molding granules, conventionally known various additives can be added as needed, as long as the objects and effects of the present invention are not impaired. . Examples of such additives include:
Dispersants such as polycarboxylates and condensed naphthalenesulfonic acid, plasticizers such as glycerin, glycols and triols, waxes, lubricants such as stearic acid (salt), polyethers, urethane-modified polyethers, and polyacrylic acid And organic polymer coagulants such as modified acrylic acid-based organic polymers, and inorganic coagulants such as aluminum sulfate, aluminum chloride and aluminum nitrate.

In the present invention, each of these components is granulated into granules for ceramic molding by a conventionally known granulation method.
More specifically, it can be formed into granules for ceramic molding by a spray drying method or oscillating extrusion. These granulation methods can be appropriately selected depending on the production amount of the ceramic forming granules, the properties of the target ceramic formed body, and the like. [Granulation of Granules: Spray Drying] In one embodiment of the present invention, granules for forming ceramics are granulated by a spray drying method. In this case, these components, that is, 100 parts by mass of the ceramic raw material powder and the specific 0.4-1.4 parts by mass of polyvinyl alcohol, 0.4-1.
An aqueous ceramic slurry for granulating ceramics granules is prepared from 4 parts by mass, 25 to 100 parts by mass of water and optional components to be added in optional amounts as required according to a conventionally known method.

The aqueous ceramic slurry thus prepared can be formed into granules for ceramic molding by a conventionally known spray drying method. The shape and particle size of the ceramic molding granules of the present invention obtained by the spray granulation method in this manner are usually 40 to 250 μm,
Preferably from 60 to 200 μm, more preferably from 80 to 1 μm.
It is preferable that the shape is 50 μm. When the particle size of the ceramic molding granules is less than the above range, the fluidity and the filling property to the mold are deteriorated, and the size of the obtained molded product and the variation of the single mass of the molded product may be increased. is there. On the other hand, when the particle size exceeds the above range, a large number of granule boundaries may be left to cause molding failure, and variations in the size and single mass of the molded product may increase.

[Granulation of granules: Oscillating extrusion]
In another embodiment of the present invention, the above-mentioned predetermined ratio of each component, namely, 100 parts by mass of ceramic raw material powder, average polymerization degree of 500 to 1700, and polyvinyl alcohol 0.4 to 1 having an average saponification degree of 88 mol% or more. 0.4 parts by mass and 0.4 to 1.4 parts by mass of a water-dispersible phenol resin having an average particle size of 0.5 to 3 μm can be directly formed into granules for ceramic molding by an oscillating extrusion method. The granules for ceramic molding of the present invention granulated by the rating extrusion method are usually 80 μm to 50 μm.
It has a particle size of 0 μm, preferably 100-300 μm, more preferably 125-200 μm. When the particle size of the ceramic molding granules is less than the above range, the fluidity and the filling property to the mold are deteriorated, and the size of the obtained molded product and the variation of the single mass of the molded product may be increased. is there. On the other hand, when the particle size exceeds the above range, a large number of granule boundaries may be left to cause molding failure, and variations in the size and single mass of the molded product may increase.

[Ceramic molded body] The ceramic molded body of the present invention is obtained by filling the ceramic molding granules of the present invention obtained as described above into a mold and molding them by a conventionally known dry pressing method. Obtainable.

It is preferable that the ceramic molded article of the present invention thus formed is subjected to a heat treatment in order to impart high strength to the molded article. The heat treatment conditions at this time are at least the curing temperature of the water-dispersed phenolic resin component present in the molded body, preferably 100 to 180 ° C, more preferably 11 ° C.
It takes about 5 to 90 minutes at a temperature of 0 to 160 ° C. In addition, such heat treatment is performed in a fluidized bed, a box-type dryer, a continuous drying furnace,
This can be done in a rotary kiln. By performing the heat treatment in this manner, the ceramic molded body of the present invention is usually 2.0 MPa or more, preferably 2.5 MPa
It is possible to provide a high bending strength of a or more.

[Ceramic Sintered Body] The thus obtained ceramic molded body of the present invention was prepared according to a conventional method.
By firing at a temperature of 00 to 1450 ° C., a ceramic sintered body free from chipping, cracks, breaks, and other appearance defects can be obtained. In particular, the frequency of appearance defects such as chipping, cracks, breaks, and the like, which frequently occur in the portions indicated by arrows in FIGS.

[0031]

Hereinafter, the present invention will be described in more detail by comparing Examples satisfying the requirements of the present invention with Comparative Examples not satisfying the requirements of the present invention. The present invention is not limited to only the above-described embodiment, and can be appropriately changed as long as it is based on the technical idea of the present invention.

[Examples 1 to 6, Comparative Examples 1 to 6] (Granulation) Ni-Cu-Z was used as a raw material powder for ceramics.
67 parts by mass of n-type ferrite powder, 33 parts by mass of water, and 0.3 parts by mass of a polycarboxylic acid ammonium salt as a binder and a dispersant having the conditions shown in Table 1,
A ferrite slurry was prepared by mixing with a commonly used wet method. The ferrite slurry was sprayed and granulated by a spray dryer to obtain spherical granules having an average particle size of 90 μm and a water content of 0.3% by mass.

(Molding of granules) Then, the obtained granules are each subjected to pressure molding at a pressure of 40 to 150 MPa by a commonly used dry method to give a density of 3.0 g / c.
m ³ rectangular parallelepiped block molded product (length: 55 mm, width:
12 mm, height: 3.0 mm) and a density of 3.2 g /
cm3 rectangular shaped block (length: 55 mm,
(Width: 12 mm, height: 2.8 mm).

[Heat treatment] Next, the block molded body thus obtained is subjected to 13
Heat treatment was performed at 0 ° C. for 30 minutes. Thereafter, the block compact was left at room temperature for 1 hour and cooled to room temperature.

[0035]

[Table 1]

[Measurement of bending strength of molded product] Next, the bending strength of these block molded products was measured using a load tester (manufactured by Aiko Engineering Co., Ltd.) in accordance with the method specified in JIS R1601. Table 2 shows the measurement results of the bending strength of the block molded body. From Table 2, it can be seen that all of the block molded bodies produced from the granules for ceramic molding of Examples 1 to 6 satisfying the necessary conditions of the present invention show high bending strength of 2.5 MPa or more. Moreover, when the bending strength of the block molded body before the heat treatment was measured in the same manner, 1.2 to 1.8 was obtained.
The result of the bending strength of MPa was obtained, and it turns out that it shows relatively high bending strength.

[0037]

[Table 2]

On the other hand, the block molded bodies produced from the ceramic molding granules of Comparative Examples 1 to 6 which do not satisfy the requirements of the present invention have a bending strength before heat treatment of 0.2 to 0.7 M.
As a result, the yield strength during handling was low. In addition, in the block molded body made from the granules for ceramic molding obtained by adding the binder solution of only polyvinyl alcohol in Comparative Examples 5 and 6, almost no change in the bending strength was observed before and after the heat treatment. A block molded body of 0.5 MPa or more could not be obtained.

[Examples 7 and 8 and Comparative Examples 7 and 8] As shown in Table 2, the ceramic molding granules obtained in Examples 1 and 3 (Examples 7 and 8)
The ceramic molding granules (Comparative Examples 7 and 8) obtained in Comparative Example 1 and Comparative Example 5 were continuously formed into a cylindrical core shape having a diameter of 1.8 mm and an L dimension of 2.0 mm. The formed body thus formed was subjected to a heat treatment at 130 ° C. for 30 minutes using a box dryer. After cooling the formed body subjected to the heat treatment in this way to room temperature, it is cut with a diamond foil to produce a drum-shaped core for a coil having a core diameter of 0.8 mm, and further fired at 1050 ° C. A sintered body was obtained. Table 3 shows the results of various evaluations performed on these compacts and sintered compacts.

[0040]

[Table 3]

From the results of the evaluation shown in Table 3, the compacts and sintered compacts (Comparative Examples 7 and Comparative Examples) produced from the granules for ceramic compacts of Comparative Examples 1 and 5 which do not satisfy the requirements of the present invention. In each of 8), the evaluation results are × or Δ, but the compacts and sintered bodies manufactured from the granules for ceramic compacts of Examples 1 and 3 satisfying the requirements of the present invention. In each of (Examples 7 and 8), the evaluation result was ○, indicating that the occurrence of chipping, cracks, and breaks was extremely small.

[0042]

According to the granules for forming a ceramic of the present invention constituted as described above, 100 parts by mass of a ceramic raw material powder and polyvinyl having an average degree of polymerization of 500 to 1700 and an average degree of saponification of 88 mol% or more are used. By granulating using 0.4 to 1.4 parts by mass of alcohol and 0.4 to 1.4 parts by mass of a water-dispersible phenol resin having an average particle size of 0.5 to 3 μm, the bending strength is improved. It is possible to provide a ceramic molding granule which is high and can form a good ceramic molded body or sintered body with few chips, cracks and breaks. (Claim 1). Further, since the ceramic molding granules do not use an organic solvent, they do not require additional equipment such as explosion-proof equipment, and are preferable in terms of environmental hygiene.

In the ceramic granules of the present invention, the polyvinyl alcohol has an average saponification degree of 94.5.
When the content is up to 97.5 mol%, the granules have a good balance of low-pressure crushing property, collapse resistance and sticking resistance, and can be used to obtain a good ceramic molded body and ceramic sintered body with small dimensional variation (claim) Item 2).

The ceramic molded body obtained by dry-press molding the ceramic molding granules of the present invention has a high bending strength of 2.0 MPa or more, preferably 2.5 MPa or more. Therefore, the occurrence of breakage and cracks during handling is reduced, and a high-density ceramic sintered body as a final product can be manufactured with high dimensional stability. (Claim 3)

Further, the ceramic sintered body obtained by firing the ceramic molded body according to the embodiment of the present invention has a high density and a high dimensional stability with few appearance defects such as chips and cracks ( Claim 4). In particular, such a ceramic sintered body having high density and high dimensional stability is suitable for a core shape having a diameter of 2 mm or less or a plate shape having a thickness of 1 mm or less (claim 6). It can be used, and can be suitably used for various electronic components that are required to be small, thin, light, and the like (claim 7). The present invention also relates to a method for producing ceramic molding granules for molding into a ceramic molding having high strength, comprising 100 parts by mass of a ceramic raw material powder and an average degree of polymerization of 500 to 170.
0, 0.4 to 1.4 parts by mass of polyvinyl alcohol having an average degree of saponification of 88 mol% or more, 0.4 to 1.4 parts by mass of a water-dispersible phenol resin having an average particle size of 0.5 to 3 μm, and water 25
An aqueous ceramic slurry containing about 100 parts by mass is prepared, and the aqueous ceramic slurry thus formed is granulated into a ceramic molding granule by a spray drying method. Unlike an organic solvent-based ceramic slurry, it is possible to easily produce ceramic molding granules capable of molding a high-strength ceramic molded body without taking explosion-proof measures (claim 8).

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of the shape of a ceramic molded body (sintered body).

FIG. 2 is a perspective view showing another example of the shape of a ceramic molded body (sintered body).

Claims (8)

[Claims] 1. A ceramic molding granule obtained by granulating a mixture of a ceramic raw material powder and a binder, wherein the ceramic raw material powder is 100 parts by mass, and the average degree of polymerization is 5 parts.
00 to 1700, 0.4 to 1.4 parts by mass of polyvinyl alcohol having an average saponification degree of 88 mol% or more, and 0.4 to 1. 1 of a water-dispersible phenol resin having an average particle size of 0.5 to 3 μm.
A granule for forming ceramics, comprising 4 parts by mass. 2. The granules according to claim 1, wherein the polyvinyl alcohol has an average degree of saponification of 94.5 to 97.5 mol%. 3. A ceramic molding obtained by dry-press molding the ceramic molding granules according to claim 1 or 2. 4. A ceramic sintered body obtained by firing the ceramic molded body according to claim 3. 5. The ceramic sintered body according to claim 4, wherein the ceramic sintered body is formed into a core having a diameter of 2 mm or less. 6. The ceramic sintered body according to claim 4, wherein the ceramic sintered body is formed into a plate having a thickness of 1 mm or less. 7. An electronic component comprising the ceramic sintered body according to claim 5. 8. A method for producing ceramic molding granules for molding into a ceramic molding having high strength, comprising 100 parts by mass of a ceramic raw material powder, an average degree of polymerization of 500 to 1700, and an average degree of saponification of 88 mol% or more. Polyvinyl alcohol 0.4 to 1.4 parts by mass, average particle size 0.5
An aqueous ceramic slurry containing 0.4 to 1.4 parts by mass of a water-dispersible phenolic resin having a thickness of 3 to 3 μm and 25 to 100 parts by mass of water is prepared, and the aqueous ceramic slurry thus formed is formed into a ceramic by a spray drying method. A method for producing granules for ceramic molding, comprising granulating into granules for ceramics.