JPH08183663A - Ceramic molding composition - Google Patents

Abstract

(57) [Summary] [Purpose] A thin film-like ceramic green sheet having a thickness of 50 μm or less and having no sheet defects such as pinholes and having excellent smoothness can be obtained. A ceramic raw material powder for forming a thin-film ceramic green sheet having a thickness of 50 μm or less, containing at least one of acetylene alcohol having one triple bond in the molecule, acetylene glycol, and an alkylene oxide adduct of acetylene glycol. A composition in which a binder composed of an organic additive and a solvent is mixed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic molding composition used for molding a thin film ceramic green sheet applied to electronic parts such as a laminated ceramic capacitor and a ceramic multilayer wiring board.

[0002]

2. Description of the Related Art Conventionally, in electronic parts such as multilayer ceramic capacitors and ceramic multilayer wiring boards, conductive paste is applied onto a ceramic green sheet by a screen printing method or the like to form a wiring layer. It was produced by a sheet laminating method in which a plurality of sheets were laminated and sintered.

Further, the ceramic green sheet is
Generally, alumina (Al ₂ O ₃ ) or mullite (3) is used depending on the electrical and thermal characteristics required as a substrate material.
Al ₂ O ₃ · 2SiO ₂ ), aluminum nitride (Al
N) or various ceramic raw material powders such as barium titanate (BaTiO ₃ ), a binder composed of an organic additive and a solvent is added to prepare a ceramic slurry, and the ceramic slurry is formed on a strip-shaped carrier film by a doctor blade method. It is produced by continuously applying and then drying.

In recent years, demands for light weight and miniaturization of various electronic parts have become more strict, and in order to satisfy the demands, the sheet thickness per layer is made thinner, the number of layers is further increased, and a laminated ceramic is also used. In a capacitor, in order to realize a smaller size and a larger capacity, a dielectric material having a high dielectric constant is used to further reduce the sheet thickness.

However, in the conventional ceramic slurry, when trying to obtain a thin green sheet, sheet defects such as pinholes are likely to occur due to poor wettability with the carrier film of the support, and a uniform coating film is formed. However, there was a limit to reducing the thickness of the ceramic green sheet.

Therefore, an average molecular weight of 40,000 to 150,000 is obtained as a ceramic slurry which can solve the above problems and reduce the thickness of the ceramic green sheet.
A composition containing a monomer and a copolymer within the above range in a binder is proposed in JP-A-6-206761.

[0007]

However, in the above composition, sheet defects such as pinholes are less likely to occur until the thickness of the ceramic green sheet is about 50 μm, and a uniform coating film can be formed, but the thickness When a thin-film ceramic green sheet having a thickness of less than 50 μm is molded, it becomes difficult to obtain a molded body without defects,
For example, when a monolithic ceramic capacitor is manufactured using such a ceramic green sheet, there is a problem that the occurrence rate of short circuit defects is extremely high.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and its object is to make an extremely thin ceramic green sheet having a thickness of 50 μm or less uniform without causing sheet defects such as pinholes. Another object of the present invention is to provide a ceramic molding composition capable of producing a ceramic green sheet having excellent smoothness and reducing the occurrence rate of short circuit defects when applied to a laminated ceramic capacitor.

[0009]

The ceramic molding composition of the present invention comprises at least one of acetylene alcohol having one triple bond in the molecule, acetylene glycol, and an alkylene oxide adduct of acetylene glycol, A composition for forming a thin-film ceramic green sheet having a thickness of 50 μm or less, which is a mixture of a ceramic raw material powder, a binder composed of an organic additive and a solvent.

In the ceramic molding composition of the present invention, the acetylene alcohol having one triple bond in the molecule is represented by the following formula having an unsaturated alcohol having a carbon-carbon triple bond acetylene bond in the molecule. Is a compound.

[0011]

[Equation 1]

As the acetylene alcohol, n =
When 1, dimethylhexynol [CH≡C-C (C
H ₃ ) (OH) CH ₂ CH (CH ₃ ) ₂ ], dimethylpropargyl alcohol [CH≡C—C (CH ₃ ) ₂ (O
H)], ethylmethylpropargyl alcohol [CH≡
C—C (CH ₃ ) (OH) C ₂ H ₅ ], methylpropylpropargyl alcohol [CH≡C—C (CH ₃ ) (O
H) C ₃ H ₇ ], isobutylmethylpropargyl alcohol [CH≡C—C (CH ₃ ) (OH) CH ₂ CH—
(CH ₃ ) ₂ ] and the like.

When n = 2, methylethylhexynol [CH≡C—C (C ₂ H ₅ ) (OH) CH ₂ CH
(CH ₃ ) CH ₃ ], when n = 3, methylpropylhexinol [CH≡C—C (C ₃ H ₇ ) (OH) CH
₂ CH (CH ₃₎ CH _3] is, when n = 4 are methyl butyl f carboxymethyl Nord _{[CH≡C-C (C 4 H 9} ) (OH)
CH ₂ CH (CH ₃ ) CH ₃ ], when n = 5, methylpentyldecinol [CH≡C—C (C ₅ H ₁₁ ) (O
H) CH ₂ CH (CH ₃ ) C ₅ H ₁₁ ], when n = 6, methylhexyldecinol [CH≡C—C (C ₆ H
₁₃ ) (OH) CH ₂ CH (CH ₃ ) C ₅ H ₁₁ ], where n =
When it is 7, methylheptyldecinol [CH≡C-C
_{(C 7 H 15) (OH} ) CH 2 CH (CH 3) C 5 H 11 ]
However, when n = 8, methyloctyldecinol [CH≡
_{C-C (C 8 H 17} ) (OH) CH 2 CH (CH 3) C 5
H ₁₁ ].

The acetylene glycol is a compound represented by the following formula having an acetylene bond and a hydroxyl group at each of the two carbon atoms adjacent to the triple bond of the alkyne.

[0015]

[Equation 2]

As the acetylene glycol, n =
When 1, hexynediol [CH ₃ CH (OH) -C≡
C-CH (OH) CH _3], dimethyl hexynediol _{[CH 3 C (CH 3) (} OH) -C≡C-C (CH 3)
(OH) CH ₃ ], dimethyloctynediol [C ₂ H
₅ C (CH ₃ ) (OH) -C≡C-C (CH ₃ ) (O
H) C ₂ H ₅ ], dimethyldecinediol [C ₃ H ₇ C
(CH ₃ ) (OH) -C≡C-C (CH ₃ ) (OH) C
₃ H ₇ ], dimethyldodecine diol [C ₄ H ₉ C (C
H ₃ ) (OH) -C≡C-C (CH ₃ ) (OH) C ₄ H
₉ ], dimethyltetradecynediol [C ₅ H ₁₁ C (C
H ₃ ) (OH) -C≡C-C (CH ₃ ) (OH) C ₅ H
₁₁ ], tetramethyldecynediol [CH ₃ CH (CH
₃ ) CH ₂ C (CH ₃ ) (OH) -C≡C-C (C
H ₃ ) (OH) CH ₂ CH (CH ₃ ) CH ₃ ], where n =
When 2, dimethyldiethyldecynediol [CH ₃ CH
(CH ₃ ) CH ₂ C (C ₂ H ₅ ) (OH) -C≡C-C
_{(C 2 H 5) (OH} ) CH 2 CH (CH 3) CH 3 ]
However, when n = 3, dimethyldipropyldecynediol [CH ₃ CH (CH ₃ ) CH ₂ C (C ₃ H ₇ ) (OH)
_{-C≡C-C (C 3 H 7} ) (OH) CH 2 CH (C
H ₃ ) CH ₃ ], when n = 4, dimethyldibutyldecynediol [CH ₃ CH (CH ₃ ) CH ₂ C (C
₄ H ₉ ) (OH) -C≡C-C (C ₄ H ₉ ) (OH) C
H ₂ CH (CH ₃ ) CH ₃ ], when n = 5, dimethyldibentyl octadecine diol [C ₅ H ₁₁ CH (CH
_{3) CH 2 C (C 5} H 11) (OH) -C≡C-C (C 5
_{H 11) (OH) CH 2} CH (CH 3) C 5 H 11 ], and the like.

Further, the alkylene oxide adduct of acetylene glycol is represented by the following formula.

[0018]

(Equation 3)

Examples of the alkylene oxide adduct of acetylene glycol include-(OA) _n and-(OA) _m.
Are preferably OE and OP homopolymers or OE and OP copolymers, and adducts of various alkylene oxides can be synthesized by known methods.

Further, in the present invention, alumina (Al ₂ O ₃ ) and zirconia (Zr) are used as the ceramic raw material powder.
O ₂ ), oxide ceramics such as barium titanate (BaTiO ₃ ) and non-oxide ceramics such as silicon nitride (Si ₃ N ₄ ), aluminum nitride (AlN) and silicon carbide (SiC) It can be applied, and various sintering aids can be added to the respective ceramic raw material powders in desired amounts.

The particle size of these ceramic raw material powders is
Those having a size of several tens of μm to submicrons can be preferably used.

In order to improve the dispersibility of the ceramic raw material powder, the raw material powder is surface-modified with a coupling agent such as a silane coupling agent, a titanate coupling agent, or an aluminate coupling agent. Can also be used.

On the other hand, since the ceramic green sheet must maintain sufficient strength and flexibility, various resins, dispersants and the like are used as organic additives in various combinations.

Examples of the resin include maleic acid resin, cellulose resin, rosin resin, petroleum resin, polyvinyl resin, butyral resin, polyester resin, acrylic resin, epoxy resin, polyamide resin, polyurethane resin, alkyd. There are resins, polyamide resins, and the like, and these resins may be used alone or in combination.

As the dispersant, any surfactant generally used in the preparation of ceramics can be used. Among them, ammonium polyoxyalkylcarboxylic acid salts, polyoxyalkylphosphoric acid ester salts and naphthalenesulfonic acid salts are particularly preferable. Formalin condensate and the like can be mentioned.

The solvent is not particularly limited as long as it is compatible with the organic additive used, and for example,
Alcohols such as toluene, xylene, benzene, hexanol, decanol, acetic ester, glyceride,
Hydrocarbons, esters, ether alcohols, ketones, chlorinated hydrocarbons, etc. can be used.

Further, when preparing a uniform solution of a predetermined amount of organic additive and solvent, if necessary, a surfactant, a plasticizer, an antistatic agent, an antifoaming agent, an antioxidant, a lubricant, A curing agent or the like can be used as appropriate.

The stirring means for forming the uniform solution is not particularly limited, but a general ball mill, a stirrer,
A Henschel mixer or the like can be used.

The ceramic raw material powder is added to and mixed with the obtained solution to prepare a mixture of the ceramic raw material powder and the binder, but the method of adding the ceramic raw material powder is not particularly limited, and a final mixture should be a uniform mixture. Good luck
It is important to perform defoaming treatment after sufficiently stirring.

[0030]

According to the ceramic molding composition of the present invention, acetylene alcohol having one triple bond in the molecule,
Since it contains at least one of acetylene glycol and an alkylene oxide adduct of acetylene glycol, the surface tension of the ceramic slurry becomes low and the wettability of the ceramic slurry to the belt-shaped carrier film becomes good. It is possible to obtain a uniform ceramic green sheet with a coating defect of 10 μm or more. Especially, the ethylene oxide adduct of acetylene glycol has a low dynamic surface tension, so high-speed gravure printing, screen printing and flexo printing are possible. It can be applied to printing, offset printing, etc., and it becomes possible to obtain a uniform thin film having a thickness of several μm.

[0031]

EXAMPLES Hereinafter, the ceramic molding composition of the present invention will be described in detail based on examples.

100 parts by weight of barium titanate (BaTiO ₃ ) as a ceramic raw material powder, 1.0 part by weight of a nonionic surfactant as a dispersant, 0.3 part by weight of dioctyl phthalate as a plasticizer, and cellosolve as a solvent. 35 parts by weight of was added to a ball mill together with balls made of zirconia and having a diameter of about 1 mm, and wet mixed for about 60 hours to obtain a slurry. When the average particle size of the slurry was measured, ultrafine particles of about 0.1 μm were obtained.

Further, 100 parts by weight of the slurry and 6 parts by weight of the same binder with respect to the ceramic raw material powder,
Two parts by weight of the additives shown in Table 1 and Table 2 were added and stirred with a Henschel mixer for about 1 hour to prepare a ceramic molding composition for evaluation.

If the amount of the additive is less than 0.1 parts by weight, the effect of uniform wettability will not be exhibited, while if it exceeds 10 parts by weight, the dynamic surface tension will be high and good printability will be obtained. It becomes difficult to give.

Therefore, the amount of the additive is 0.1-10.
Parts by weight, especially 2 to 4 parts by weight are preferred.

Using the thus obtained ceramic molding composition for evaluation, a thickness of about 20 μm was obtained by gravure printing.
The ceramic green sheet of was produced. The printing speed was 40 m / min, and a polyester film was used as the carrier film.

The surface condition of the ceramic green sheet produced according to the above procedure was observed with a stereoscopic microscope and a scanning electron microscope to evaluate the coating property and smoothness, respectively.

The applicability was evaluated by irradiating light from below the ceramic green sheet with a stereoscopic microscope and reading the number of coating film defects such as pinholes per 1 mm ² of the ceramic green sheet at a magnification of 80 from the opposite side. The case where no coating film defects were recognized was evaluated as ◯, and the case where one or more coating film defects were recognized was evaluated as x.

On the other hand, the smoothness was evaluated by measuring the dimensional accuracy of the film thickness from the fracture surface of the ceramic green sheet with a scanning electron microscope, and the accuracy of the film thickness was less than 11%.
Those with 11% or more and less than 21% were evaluated as ◯, and those with 21% or more were evaluated as x.

Next, internal electrodes are formed on the ceramic green sheets by a screen printing method, 50 ceramic green sheets are laminated and pressure-bonded, and the pressure-bonded body is approximately 40
After removing the binder in the air at a temperature of 0 ° C.,
It was baked at a temperature of about 1300 ° C. for about 2 hours.

Subsequently, an external electrode is formed on the fired body,
A multilayer ceramic capacitor for evaluation having a size of 2.00 mm × 1.25 mm square and a capacitance of 1 μF was obtained.

A DC voltage of 100 V was applied to the evaluation multilayer ceramic capacitor to investigate the number of short circuit defects, and the number of short circuit defects was less than 10 out of 300 measured samples. ○ less than 16
16 or more were evaluated by x.

As comparative examples, the same evaluations were carried out on the ceramic green sheets and the laminated ceramic capacitors prepared under the same conditions as those of the above-mentioned examples, using no additive and using an ethylene oxide adduct of fatty acid as an additive. did.

[0044]

[Table 1]

[0045]

[Table 2]

As is clear from the above results, in sample No. 1 containing no additive, sheet defects such as pinholes were recognized, smoothness was impaired, short circuit failure occurred, and fatty acid was added with ethylene oxide. Sample No. 22 containing the additive as the additive had good coatability, but poor smoothness, and a short circuit defect occurred.

On the other hand, all of the products of the present invention have obtained satisfactory results, but those containing an alkyl oxide adduct of acetylene glycol are particularly excellent in coating property and smoothness and are short-circuited. It can be seen that the number of defects has also decreased sharply.

In this example, the case where the ceramic molding composition of the present invention was applied to a laminated ceramic capacitor was described in detail. However, the present invention is not limited to this and other ceramic multilayer wiring boards and the like can be used. It is also applicable to electronic components.

[0049]

As described above, the ceramic molding composition of the present invention contains at least one of acetylene alcohol having one triple bond in the molecule, acetylene glycol, and an alkylene oxide adduct of acetylene glycol. An extremely thin ceramic green sheet having a thickness of 50 μm or less can be made to have uniform and excellent smoothness without sheet defects such as pinholes, and when applied to a laminated ceramic capacitor or the like, a short circuit occurs. The failure rate can be significantly reduced

Claims (1)

[Claims] 1. A composition in which a ceramic raw material powder used for forming a thin-film ceramic green sheet is mixed with a binder composed of an organic additive and a solvent, the composition being one triple bond in the molecule. A ceramic molding composition comprising at least one of acetylene alcohol, acetylene glycol or an alkylene oxide adduct of acetylene glycol having