JPS60231458A - Manufacture of ceramic dielectic - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical field to which the invention pertains) The present invention relates to a method for manufacturing a ceramic dielectric material that is dense, has a high sintered density, and exhibits stable firing shrinkage.

Modern industrial materials are required to have a variety of functionality, and in the field of ceramic dielectrics, sintered bodies are becoming more compact.

There is a strong demand for dimensional stability.

(Prior art and its problems) As a method of manufacturing such a ceramic dielectric, a ceramic dielectric green sheet (hereinafter referred to as a green sheet), which is a mixture of a ceramic dielectric raw material powder and an organic binder, is heated in a predetermined manner. A method of molding into a shape and then firing it is becoming widely used.

That is, as a ceramic dielectric raw material powder, for example, barium titanate to which one of titanate, stannic acid ring, zirconate, or a mixture thereof is added is sufficiently uniformly mixed in a ball mill, and then an organic binder and a plasticizer are added. A suitable amount of agent, solvent, etc. is added and mixed further to make a ceramic dielectric slip (hereinafter referred to as slip). This slip is shaped into a plate with a thickness of about 0.1 to 1.4 m using a doctor blade method, and a green sheet is formed into a predetermined shape and then sintered at a predetermined temperature to form a ceramic dielectric. However, ceramic dielectrics using slip produced by conventional methods have the following problems.

Slips are usually obtained by wet-pulverizing ceramic dielectric raw material powder with water using a ball mill or the like, drying and removing the water, adding an organic binder, a solvent, etc., and mixing uniformly using a ball mill or the like.

However, according to this method, primary particles reagglomerate in the drying process after pulverizing and mixing the ceramic dielectric raw materials. Furthermore, even in dry pulverization, the smaller the pulverized primary particles, the more likely they will agglomerate, and even if organic binders, plasticizers, solvents, etc. are added to and mixed with the agglomerated ceramic dielectric raw material powder, the ceramic dielectric raw material powder will become monolithic. - It cannot be disintegrated into particles, and it is extremely difficult to uniformly disperse them in the state of primary particles.

Therefore, green sheets are usually formed and fired with weak agglomeration occurring locally. Therefore, the sintered density of the obtained ceramic dielectric is small.

The surface is hydrophilic, so it is very easy to wet with water and alcohol, but it is difficult to get wet with trichlorethylene, toluene, etc. We also discovered that alcohol-based solvents are good solvents for butyral resin, which is an organic binder commonly used in green sheets.

The viscosity of a solution containing an organic binder in a solvent is
An organic binder is added that is below the level that does not hinder the disintegration of the turtle material raw material powder and prevents the disintegrated particles from coming into direct contact with each other, and the ceramic dielectric raw material powder becomes a single particle. Thoroughly disintegrate the grains.

By creating a slip with a thin film of organic binder on the particle surface, and then drying and removing the solvent, the particle surface is coated with a thin film of organic binder. After that, a suitable amount of solvent, organic binder, and plasticizer was gradually added and mixed to provide the sorting characteristics necessary for tape forming and punching, and the ceramic dielectric raw material was sufficiently and uniformly dispersed down to the primary particles. The slip is obtained and this slip is molded,
When fired, it was confirmed that a dense ceramic dielectric material with a high degree of sintering and a stable firing shrinkage rate could be obtained.

The present invention provides a ceramic dielectric in which a ceramic dielectric raw material powder, an organic binder, a solvent, and a plasticizer are mixed and fired, and the viscosity of the solution containing the organic binder and the solvent does not hinder the disintegration of the ceramic dielectric raw material powder. The ceramic dielectric raw material powder is granulated until it becomes a single particle by adding and mixing an organic binder that prevents the granulated particles from coming into direct contact with each other in an amount that is below the level of granulation, and then dried. The present invention relates to a method for producing a ceramic dielectric, which involves removing the solvent, adding and mixing the amount of solvent, organic binder, and plasticizer necessary to impart the sheet properties necessary for tape forming and punching, followed by forming and firing.

(Material example) In the present invention, the ceramic dielectric raw material powder is not particularly limited; for example, barium titanate powder to which one of titanate, stannate, zirconate, etc. or a mixture thereof may be added. used. Butyral resin, acrylic resin, vinyl acetate copolymer, polyvinyl alcohol, vinyl chloride, methacrylate, etc. are used as the organic binder. As the plasticizer, phthalate esters such as DOP and DBP, and glycol esters such as triethylene glycol and polyalkylene glycol are used. Solvents include trichlorethylene and butanol.

Ethyl alcohol, methyl alcohol, etc. are used.

The viscosity of a solution obtained by adding an organic binder to a solvent is preferably 20P (voids) at maximum, and more preferably in the range of IP to 3P. The amount of the organic binder added is preferably 0.5 to 20 parts by weight per 100 parts by weight of the ceramic dielectric raw material powder, and more preferably 08 to 1.8 parts by weight.

The amount of organic binder and plasticizer required to impart sheet properties necessary for tape forming and punching is 3.0 to 66 parts by weight of organic binder and 2 parts by weight of plasticizer per 100 parts by weight of ceramic dielectric raw material powder. The content is preferably .1 to 3.9 parts by weight, and more preferably 4.0 to 5.6 parts by weight of the organic binder and 2.6 to 3.4 parts by weight of the plasticizer.

Tape molding is a method of molding in the present invention.

There are no particular limitations, such as press molding, imitation molding, extrusion molding, etc., but tape molding is preferable. In addition, the firing is usually performed by a known method, and the average particle size is 0.8 μm.
To 100 parts by weight of barium titanate powder, 1.2 N parts of butyral resin as an organic binder and 40 parts by weight of ethanol as a solvent were weighed and mixed in a hole mill for 12 hours to form single particles of ceramic dielectric raw material powder. A mixed slip pellet was obtained which was sufficiently disintegrated.

Next, the solvent was removed from the mixed slip by drying to obtain primary particles for a ceramic dielectric coated with an organic binder. Furthermore, primary particles for ceramic dielectrics 101.2
Based on the weight part, 4.8 parts by weight of butyral resin as an organic binder, 3.0 parts by weight of butylbenzyl phthalate as a plasticizer, and 2 parts of 40.0 parts of an azeotrope of ethanol and trichlorethylene as a solvent. Add 1 in ball mill
Mixing was carried out for 2 hours to obtain a mixed slip (Bl).Then, the mixed slip CBlk tape was molded onto a carrier film to a thickness of 0.95 mm, and after drying, it was peeled off from the carrier film to obtain Green Sea)-(r Obtained.

Next, this green 7-t was cut into a size of 95 x 95 nm, placed on a zirconia refractory setter, and heated to 11 mm in an electric furnace.
, and fired at 400° C. for 1 hour to obtain a ceramic dielectric. The resulting ceramic dielectric has a sintered density of 5.60 g/c
m', and the firing shrinkage rate was 29.0±0.1.

On the other hand, as a comparative example, 100 parts by weight of the same ceramic dielectric raw material powder as that used in the above example, 60 parts by weight of butyral resin as a binder, 3 parts by weight of butylbenzyl phthalate as a plasticizer, and ethanol and trichloride as a solvent were used. A ceramic dielectric was produced by adding 40 parts by weight of an azeotropic mixture with chlorethylene and performing mj mixing for 24 hours in a ball mill in the same process as in the above example, and the sintered density was 5.50 g/cm'. , the firing shrinkage rate is 30.4
Ceramic dielectric is produced by cooling and mixing an organic binder in an amount such that ±0.6% is less than the level that does not prevent the disintegration of the ceramic dielectric raw material powder, and in an amount that prevents the disaggregated particles from coming into direct contact with each other. The raw material powder is granulated into single particles, dried to remove all the solvent, and then added with the necessary amounts of solvent, organic binder and plasticizer to impart the sheet properties necessary for forming and punching. Since the materials are added and mixed, then molded and fired, it is possible to produce a ceramic dielectric that is dense, has a high sintered density, and has a stable firing shrinkage rate.

Continued from page 1 0 Inventor Mori Kamiyama 4-1 Higashimachi, Hitachi City Hitachi Chemical Co., Ltd. Ibaraki Laboratory

Claims (1)

[Claims] 1. Ceramic dielectric raw material powder, organic binder. For ceramic dielectrics in which a solvent and a plasticizer are mixed and fired, the viscosity of a solution containing a solvent and an organic binder is below a level that does not interfere with the disintegration of the ceramic dielectric raw material powder, and the disintegrated particles are An amount of organic binder that prevents direct contact is added and mixed, the ceramic dielectric raw material powder is granulated until it becomes a single particle, and then dried to remove the solvent. A method for producing a ceramic dielectric, which comprises adding and mixing a solvent, an organic binder, and a plasticizer in amounts necessary to impart note characteristics, followed by molding and firing.