JPS62158003A - Manufacture of ceramic green sheet - 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 (Field of Industrial Application) The present invention relates to a method of manufacturing a ceramic green sheet used as a material such as a dielectric material of a multilayer capacitor.

(Prior Art) In general, a method called a doctor blade method or a Harris roll coater method is employed to manufacture ceramic green sheets from a ceramic raw slurry containing a binder by a coating method.

For example, in the doctor blade method, as shown in Figure 3,
Rolls 1 and 2 rotating in the directions of arrows A and A
A raw material reservoir 5 is placed on a carrier film 4 that is conveyed in the direction shown by arrow A3 by a stainless steel belt 3 stretched between the two.

A ceramic raw material slurry 6 is supplied to the raw material reservoir 5, and the ceramic raw material slurry 6 is flowed out from the raw material reservoir 5 to apply the ceramic raw material slurry 6 onto the carrier film 1. This coating thickness is adjusted by a blade 7 provided in the raw material reservoir 5. The ceramic raw material slurry 3 coated on the gear rear film 4 is sent to a drying chamber 8 and dried, and the ceramic raw material slurry 6 dried in the drying chamber 8 is peeled off from the carrier film 4 as a ceramic green sheet 9.

Although not shown in detail, in the reverse roll coater method, the ceramic raw material slurry adhered to a roll is transferred to a carrier film, thereby coating each carrier film with the ceramic raw material slurry. Ceramic green sheets are manufactured through the same process as the method.

F
As shown in FIG. 4, this ceramic raw material slurry 6 contains:
Dry with hot air or hot air supplied directly from above as shown by the arrow.

Incidentally, when drying the ceramic raw material slurry 6 with hot air, the speed of the hot air needs to be suppressed as much as possible. This is because when the speed of the hot air is increased, the evaporation of the solvent from the surface layer of the ceramic raw material slurry 6 shown in FIG. becomes sufficient, and the variation in film thickness becomes large.
■ Differences in drying occur due to variations in film thickness, causing cracks in the ceramic green sheet 9. ■ Since the surface of the ceramic raw material slurry 6 on the carrier film 4 is dried first, the internal solvent becomes difficult to evaporate. Solvent vapor suddenly blows out and pinholes are generated in the ceramic green sheet 9.

(2) There is a large difference in drying speed between the surface of the ceramic raw material slurry 6 and the inner layer, causing many problems such as curling of the ceramic green sheets 9.

Therefore, it is preferable to suppress the speed of the hot air as much as possible, but if this is done, there is a problem that it takes a long time to dry the ceramic raw material slurry 6.

(Objective of the Invention) An object of the present invention is to provide a method for producing a ceramic green sheet, which allows a ceramic green sheet of excellent quality to be obtained in a relatively short drying time.

(Structure of the Invention) Therefore, the present invention is characterized in that the ceramic raw material slurry coated on the carrier film is dried by supplying the heat of hot air through the film that provides vapor permeability. That is, in the present invention, the ceramic raw material slurry coated on the carrier film is prevented from being directly hit by hot air, and a highly concentrated solvent atmosphere with a substantially constant temperature is formed above the ceramic raw material slurry. or dry evenly.

(Effects of the Invention) According to the present invention, a highly concentrated solvent atmosphere with a substantially constant temperature is formed above the ceramic raw material slurry to be dried, so that the ceramic raw material slurry is dried uniformly in all parts, and is relatively It is possible to obtain high-quality ceramic green sheets with little variation in film thickness and without cracks, pinholes, or curling by drying in a short time.

(Example) Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

In the present invention, instead of supplying hot air directly to the ceramic raw material slurry 6 coated on the carrier film 1 as shown in FIG. 4, as shown in FIG. Hot air is supplied from above vapor permeable films 11 such as filter paper arranged at intervals of ~10 mm, and the ceramic raw material slurry 6 is heated by the heat of the hot air.
Allow to dry.

Note that in FIG. 1, parts corresponding to those in FIG. 4 are designated by corresponding reference numerals, and redundant explanations will be omitted.

In this way, the hot air supplied from above the film 11 does not directly hit the ceramic raw material slurry 6, and the heat contained in the hot air is generated between the film 11 and the ceramic raw material slurry 6. It is transmitted to the ceramic raw material slurry 6 through the space S where it is located. As a result, the ceramic raw material slurry 6 is heated and the solvent therein evaporates into the space S as shown by the arrow, and a highly concentrated solvent atmosphere with a constant temperature is formed in the space S.

In this solvent atmosphere at a constant temperature, the ceramic raw slurry 6 is dried uniformly in all areas, resulting in a high-quality ceramic green sheet 9 with less variation in film thickness and fewer cracks and pinholes.

Incidentally, in Fig. 1, when the hot air temperature is 60°C and the wind speed is 0.3 m/sec, the variation R in the film thickness of the obtained ceramic green sheet 9 (film thickness 70 μm) is as follows.
R=Iμm, and no cracks or pinholes were observed. On the other hand, according to the conventional method, the variation R in the film thickness of the obtained ceramic green sheets 9 is R=
At 4 μm, cracks and pinholes were observed.

In the above embodiment, as shown in FIG. 2, a heater H is arranged under the carrier film 4,
The ceramic raw material slurry 6 may also be heated from below the carrier film 4 by connecting a power source E to the carrier film 4. In this way, the drying time of the ceramic raw material slurry 6 is further shortened.

[Brief explanation of drawings]

1 and 2 are explanatory diagrams of two embodiments of the method for producing ceramic green sheets according to the present invention, respectively. FIG. 3 is an explanatory diagram of the method for producing ceramic green notebooks by the doctor blade method. FIG. 2 is an explanatory diagram of a conventional method for manufacturing a ceramic green sheet. 4. Carrier film, 6. Ceramic raw material slurry, 11. Vapor permeable film, 11. Heater. Patent applicant: Murata Manufacturing Co., Ltd. Agent: Patent attorney: Mr. Maeda and two others Figure 1 Figure 3 Figure 4 Bottom

Claims (1)

[Claims] (1) In the method for manufacturing a ceramic green sheet, a ceramic raw material slurry coated on a carrier film is dried by applying hot air to it, and then a green sheet is obtained by peeling the dried ceramic raw material slurry from the carrier film. A method for producing a ceramic green sheet, comprising supplying heat to a ceramic raw material slurry on a carrier film through a vapor-permeable film to dry it.