JPS59221362A - Electrically conductive paste composition - Google Patents

Abstract

PURPOSE:To obtain the titled composition for the coating of an unfired ceramic sheet, and capable of producing ceramic parts free from cracks and deformation, by mixing an electrically conductive metallic component having fine particular form with a liquid carrier containing butyl carbitol, turpentine oil, limonene, etc. CONSTITUTION:The objective composition can be prepared by mixing (A) 40- 75% of fine particles of an electrically conductive metallic component (e.g. silver, palladium, platinum, nickel, copper, their mixture or their alloy, etc.) with (B) a liquid carrier containing (i) 5-50% of butyl carbitol and (ii) 95-50% of turpentine oil, limonene, decaline and/or amylbenzene.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates primarily to a liquid carrier for a particulate metal electrode material used in the manufacture of multilayer ceramic capacitors, in particular consisting of such a liquid carrier and a particulate metal component. The present invention relates to a conductive paste composition.

Conventional laminated ceramic capacitors are manufactured by manufacturing an unfired raw dielectric porcelain sheet by applying a dielectric porcelain paste containing finely divided dielectric porcelain material as its main component onto the surface of a substrate and drying it. Next, on top of this unfired electric porcelain sheet,
It is manufactured by applying a conductive paste composition, such as silver paste, and sequentially laminating a plurality of sheets thus obtained.

When the silver layer is formed by a printing method, it is formed by placing silver paste on a mesh template such as a screen printing plate and imprinting it into a desired shape, and is used as an electrode, that is, a plate of a capacitor. In this way, a desired number of silver electrodes and dielectric ceramic materials coated are alternately stacked. The alternating silver layers are slightly protruded to be exposed at both ends of the laminate and are fired at the firing temperature of the dielectric porcelain material to form a laminate porcelain capacitor. Then, each electrode layer exposed on both ends of the baked capacitor is silver-plated with silver paste, and the end silver-plated on one side and all of the electrode layers exposed on that side are interconnected. Then, the silvered end on the opposite side and all the electrode layers exposed on that side are connected to each other and baked again. Next, conductive wires are joined to the silver-plated ends by means such as soldering, thereby completing a multilayer porcelain capacitor. Silver plating on the exposed end portions of each electrode layer may be performed for the first time before processing.

In this case, it is sufficient to simply bake it once.

The dielectric porcelain paste is made of a fine particulate dielectric porcelain material such as glass, barium titanium, titanium dioxide, lead titanate, lead zirconate, manganese dioxide or strontium titanate, and a temporary resinous organic binder. and a solvent that dissolves this resinous organic binder to form a slurry. The organic binder component must have good flammability and form a flexible plate. Otherwise, cracks and other defects may occur during operation.

Further, the electrode-forming metal component is not limited to silver, but must be a metal that does not melt at the firing temperature. Examples of such metal components include silver, palladium, platinum, nickel, copper, and mixtures or alloys of one or more of these. By dispersing these metal components in a solvent, a conductive paste composition to be applied to an unfired dielectric ceramic sheet is prepared. In this case, it is very important that the solvent used to disperse the metal component does not excessively dissolve the temporary organic binder component contained in the unfired dielectric ceramic sheet. Otherwise, during the lamination, compression, and sintering processes, the electrode-coated dielectric porcelain thin plate may bend, crack, or deform, which is a fatal defect in the manufacture of porcelain capacitors. .

The drawback of the prior art is that only butylcarpitol or terpineol was used as the solvent for the conductive paste composition, so the temporary organic binder component contained in the unfired electric porcelain sheet dissolved by a solvent,
During the lamination, compression, and firing steps, fatal defects such as bending, cracking, or deformation of dielectric ceramic thin plates could not be avoided.

Purpose of the Invention Therefore, the present invention aims to solve the problem of cracking or deformation occurring during the lamination, compression, and firing processes when manufacturing ceramic electronic components by applying a conductive paste composition onto an unfired porcelain sheet. It is an object of the present invention to provide a conductive paste composition that does not cause such fatal defects.

Structure of the Invention In order to achieve the above object, the present invention provides a conductive paste composition comprising a mixture of a particulate conductive metal component and a liquid carrier, the liquid carrier comprising butyl calpitol, turpentine oil, It is characterized by containing at least one selected from limonene, decalin, and amylbenzene.

Green dielectric porcelain sheets are generally thin flexible sheets composed of a mixture of dielectric porcelain material and a fugitive organic binder. Here, the temporary organic binder is
Usually, cellulose resin, butyral resin or acrylic resin is often used.

Butyl calpitol dissolves a temporary organic binder contained in the unfired dielectric porcelain sheet, that is, cellulose resin, butyral resin, or acrylic resin, and applies the fine particulate metal component to the unfired dielectric porcelain sheet. form a liquid carrier suitable for

On the other hand, turpentine, limonene, decalin or amylbenzene are insoluble in these temporary organic binders.

Therefore, it can be obtained by appropriately mixing butyl calpitol, which dissolves the temporary organic binder contained in the unfired dielectric porcelain sheet, with turpentine oil, limonene, decalin, or amylbenzene, which does not dissolve the temporary organic binder. When the conductive paste composition according to the present invention is applied to an unfired dielectric ceramic sheet to form an electrode pattern, temporary organic bonding in the dielectric ceramic sheet due to the liquid carrier in the conductive paste composition The solubility of the agent is appropriately adjusted so that the dielectric ceramic sheet does not deteriorate during lamination and compression processing. Furthermore, when the dielectric porcelain laminate thus obtained is sintered using a conventional sintering method, all organic substances are burnt out during the sintering process, resulting in a laminate with very satisfactory properties. A shaped porcelain capacitor is obtained.

The mixing ratio of butylcarpitol and turpentine, limonene, decalin, or amylbenzene is desirably 40% or less, and is practically effective if it is 50% or less. However, since it is necessary to ensure a certain degree of solubility in the temporary organic binder in the unfired dielectric porcelain sheet, the mixing ratio of butyl calpitol must be at least 5% or more, so turpentine oil, limonene, decalin or The mixing ratio of both is selected so that the mixing ratio of amylbenzene is 95% or less.

The liquid carrier of the conductive paste composition must also contain a temporary organic binder for the particulate metal component. This organic binder must be burnt out during the sintering process. As such an organic binder, cellulose resin, butyral resin, acrylic resin, etc. are suitable, and one or more of these resins are contained. The temporary organic binder also effectively binds the particulate metal component to ensure its attachment to the green dielectric porcelain sheet throughout the lamination and compaction process. It is necessary to make it exist in the liquid carrier in sufficient amount. Usually, an amount of 3 to 50% of the total weight of the liquid carrier is effective, but in the present invention,
5-20% is suitable. Furthermore, the content of the fine particle metal component is 40 to 75% due to the need to ensure desired fluidity.
A suitable range is preferably 45 to 65%.

In addition, the butyl calpitol has a temperature of 220 to 235°C.
Turpentine oil has a temperature of 153-175°C, limonene has a temperature of 176.
The boiling point or boiling point range is 5℃, decalin is 196℃, and amylbenzene is 202”O (all under atmospheric pressure).
It is composed of things that have At a boiling point lower than this, the rate of volatilization is too fast, and at a boiling point higher than this, the rate of volatilization is too slow to be practical.

Example 1 A liquid carrier was prepared by mixing butyl calpitol and limonene at a ratio of 1:2 and dissolving 6% of ethyl cellulose therein. A conductive paste composition containing silver as a conductive component was prepared by adding silver powder to this liquid carrier in the above ratio range and mixing in a three-roll paint mill.

The conductive paste composition thus prepared was 9
Suitable for combination with low-temperature sintered dielectric porcelain materials that are sintered at low temperatures of 50°C or lower, for example, unfired dielectric porcelain sheets using dielectric materials such as glass, and are suitable for lamination, compression, and firing processes. During this process, a multilayer ceramic capacitor could be manufactured without any defects such as cracking or deformation.

Effects of the present invention As described above, the present invention provides a conductive paste composition comprising a mixture of a particulate conductive metal component and a liquid carrier, wherein the liquid carrier contains butyl calpitol, turpentine oil, limonene, At least one selected from decalin and amylbenzene, so that when manufacturing a ceramic electronic component by applying a conductive paste composition to an unfired porcelain sheet, lamination, It is possible to provide a conductive paste composition that does not cause fatal defects such as cracking or deformation during the compression and firing steps.

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Claims (5)

[Claims] (1) In a conductive paste composition formed by mixing Iff particulate conductive metal component and a liquid carrier, the liquid carrier includes butyl calpitol, turpentine oil, limonene,
A conductive paste composition comprising at least one selected from decalin and amylbenzene. (2) The liquid carrier contains 5% of the butylcarpitol.
% to 50%, and 95% to 50% of at least one selected from turpentine, limonene, decalin, or amylbenzene. thing. (3) The liquid carrier contains 3% to 50% of one or more selected from cellulose resin, butyral resin, or acrylic resin. The conductive paste composition according to item 1 or 2. (4) According to claim 1, the fine particulate metal component is composed of silver, palladium, platinum, nickel, copper, or a mixture or alloy of one or more of these. conductive paste composition. (5) The mixing amount of the fine particulate metal component is 40% to 7%.
5% of the conductive paste composition according to claim 1 or 4.