JPH03206A - Manufacture of green ceramic sheet - Google Patents

Abstract

PURPOSE:To make it possible to obtain green ceramic sheet with not defect at low cost by a method wherein one green ceramic sheet is produced by alternately laminating two kinds of green ceramic sheets by two layers and more. CONSTITUTION:After the position of a vessel 24a is adjusted so as to allow to apply ceramic slurry 22a to carrier film 16, a gravure roller is arranged near the flat part 20 of the carrier film. And, by rotating gravure roller 26a, the ceramic slurry 22a is applied by the predetermined thickness to the under surface of the carrier film 16. With the transferring of the carrier film 16, the ceramic slurry 22a applied to the under surface of the carrier film 16 is brought to a drier 30 so as to be dried into green ceramic sheet 32a. After that, in the same manner as the production of the first layer green ceramic sheet 32a, ceramic slurry 22b is again applied by the predetermined thickness to the under surface of the green ceramic sheet, which is produced previously, with a gravure roller 26b and then dried so as to produce the green ceramic sheet 32b as the second layer.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a green ceramic sheet, and in particular to a method for manufacturing a ceramic green sheet, which is used in laminated ceramic sheet electronic components such as a laminated ceramic capacitor and a laminated ceramic substrate. The present invention relates to a sheet manufacturing method.

[Prior art]

As a conventional method for manufacturing laminated ceramic electronic components, there is a method in which an internal electrode paste is printed on a raw ceramic sheet, dried, and a predetermined number of the thus formed raw ceramic sheets are laminated and then press-bonded.

In addition, another method has been devised in which the internal electrode paste is printed on a green ceramic sheet with a carrier film attached, is dried, is laminated by thermocompression bonding, and the process of peeling off the carrier film is repeated. ing.

(Problems to be Solved by the Invention) In either method, the ceramic green sheet is an IN or single layer formed by a doctor blade method or the like. Therefore, in order to increase capacity, ceramic raw sheets are made thinner (
If this occurs, defects such as bores and pinholes will become apparent in the raw ceramic sheet, and the conductive paste used as the internal electrode material will penetrate through the defects and conduct with the underlying layer, resulting in a drop in withstand voltage and even a short circuit accident. There were problems such as the occurrence of

In order to solve these problems, there has been a method of inserting a ceramic raw sheet (white sheet) on which no internal electrode is formed between the ceramic raw sheets to be laminated and the internal electrodes.

However, although this method can prevent the breakdown voltage drop and short circuit accidents due to conduction of the internal electrodes as described above, it is difficult to increase the capacitance because the dielectric layer (ceramic N) between the internal electrodes cannot be made thin. To do this, the raw ceramic sheet itself must be made thin, and if it is too thin, it becomes difficult to handle. Furthermore, when producing the above-mentioned white sheet, an expensive carrier film must be used, resulting in high costs.

Therefore, the main object of the present invention is to provide a method for manufacturing a green ceramic sheet that can produce a green ceramic sheet without defects at a lower cost.

[Means for solving problems]

This invention prepares two types of ceramic slurries each made of a different binder system, repeats the process of applying the ceramic slurry and then drying it one or more times alternately for the two types of ceramic slurries, so that 2N or more is integrated. This is a method for manufacturing a ceramic green sheet, in which a single laminated ceramic green sheet is formed on a carrier film.

[Effect]

One of the two types of ceramic slurry is applied onto the carrier film and then dried. and,
Another ceramic slurry is continuously applied onto the dried ceramic green sheet and then dried. If necessary, the application and drying of the two types of ceramic slurries are repeated to obtain one raw ceramic sheet in which two or more layers are laminated on the carrier film.

〔Effect of the invention〕

According to this invention, two or more layers of two types of green ceramic sheets are alternately laminated to form one green ceramic sheet, so even if there is a defect such as a bore or pinhole in the IN, it can be covered with another layer. Therefore, the occurrence of defects caused by such defects can be minimized.

In addition, since there is no need to make the thickness of each green ceramic sheet extremely thin, it is easier to handle, and the swelling (leaching of conductive paste and resulting deformation of the green ceramic sheet) that was a problem when the sheet was thin is alleviated. be done.

Furthermore, compared to the case where a white sheet is used, the amount of carrier film consumed can be reduced, so high costs can be avoided.

Furthermore, if ceramic slurries with the same binder are applied in a layered manner, swelling tends to occur, but since each ceramic slurry has a different binder system, swelling can be avoided.

The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

〔Example〕

FIG. 1A and FIG. 1B are illustrative views showing one embodiment of the present invention. In the manufacturing apparatus 10 of this embodiment, a carrier film 16 is passed between the feed roller 12 and the take-up roller 14. As the carrier film 16, one that has been subjected to a mold release treatment on one side, such as a polyethylene film coated with a silicone resin, can be used.

The carrier film 16 fed out from the feeding roller 12 is pulled by four tension rollers 18 to form a flat portion 20, and
Guided by 4.

Below the flat portion 20 of the carrier film 16, containers 24a and 24b for storing ceramic slurries 22a and 22b, respectively, are provided so as to be movable up and down.

Here, the ceramic slurries 22a and 22b are each made of two different types of binder systems. For example, the ceramic slurry 22a is formed using polyvinyl butyral (PVB) or an acrylic resin as a binder and toluene as a solvent; 22b is formed using polyvinyl acetate (PVAC) as a binder and water as a solvent.

Gravure rollers 26a and 26b are arranged above the containers 24a and 24b, respectively, to lift the ceramic slurries 22a and 22b, supply them to the flat portion 20, and perform so-called gravure transfer. Further, blades 28a and 28b are arranged near the gravure rollers 26a and 26b, respectively, to adjust the amount of passage of the lifted ceramic slurries 22a and 22b.

A dryer 30 is disposed on the conveyance path of the carrier film 16, and this dryer 30 dries the ceramic slurries 22a and 22b applied by the gravure rollers 26a and 26b, respectively. shall be.

First, as shown in FIG.
Adjust the position of the gravure roller 26a to the flat part 20.
Place nearby.

Then, by rotating the gravure roller 26a in the direction of arrow 34, the ceramic slurry 2 in the container 24a is
2a is applied to the lower surface of the carrier film 16 fed out from the feeding roller 12 to a predetermined thickness. The thickness of the applied ceramic slurry 22a is determined by the gravure roller 26.
It depends on the size of the gap between a and the tip of the blade 28a. Therefore, the blade 28a is configured such that the gap can be adjusted as desired.

As the carrier film 16 is transferred, the ceramic slurry 22a applied to the lower surface of the carrier film 16 is
It is brought to the above-mentioned dryer 30, where it is dried to become a green ceramic sheet 32a. The one-layer ceramic raw sheet 32a thus formed is sequentially wound up by the winding roller 14 together with the carrier film 16, and the first step is completed.

Then move on to the second process. As shown in Figure 1B, 1
The take-up roller 14 that took up the raw ceramic sheet 32a (and carrier film 16) in the second step is set on the delivery side, and the empty delivery roller 12 is set on the take-up side. Also, this time, in order to apply a different type of ceramic slurry 22b to the raw ceramic sheet 32a than in the previous process, the position of the container 24b is adjusted, the gravure roller 26b is placed near the flat part 20, and the container 24a is keep away.

Thereafter, in the same manner as the first time, the ceramic slurry 22b is again applied to the lower surface of the previously formed ceramic green sheet 32a to a predetermined thickness using the gravure roller 26b, and dried to form the second layer of the ceramic green sheet 32b. do.

According to experiments by the present inventors, ceramic slurry 2
When the binder system of 2a and 22b is the same, the first
When the second layer of ceramic green sheet was formed in the process shown in Figure B, swelling occurred between it and the first layer. On the contrary,
If the binder or solvent systems of the two ceramic slurries were made different according to the present invention, such swelling would not occur.If it is desired to further increase the number of laminated layers, the above-mentioned process may be repeated alternately, as shown in Figure 2. A plurality of layers of ceramic raw sheets 32a and 32b may be formed.

By repeating the application and drying of the ceramic slurries 22a and 22b a predetermined number of times in this way, a single ceramic green sheet having a desired thickness in which two or more layers of two types of ceramic green sheets are integrally laminated alternately is obtained. .

Note that the types of ceramic slurry are not limited to two types as in the above embodiment, but three or more types of ceramic slurry may be used to laminate green ceramic sheets 32a, 32b, and 32c as shown in FIG. You may.

Furthermore, in the above-described embodiment, the carrier film 16 was wound up and reset for each process, but this can be repeated continuously without removing or resetting the roller by making the carrier film 16 endless. You can also do this.

Furthermore, the method of applying the ceramic slurry is not limited to the gravure transfer method as in the above-mentioned embodiments, but may be other methods such as a doctor blade method.

[Brief explanation of drawings]

Figures 1A and 1B are illustrative diagrams showing one embodiment of the present invention, with Figure 1A showing the manufacturing process of the first layer of green ceramic sheet, and Figure 1B showing the manufacturing process of the second layer of green ceramic sheet. The manufacturing process is shown. FIG. 2 is an illustrative view showing a state in which two types of raw ceramic sheets are laminated in multiple layers. FIG. 3 is an illustrative view showing a state in which three types of green ceramic sheets are laminated. In the figure, 16 is a carrier film, 22a and 22b are ceramic slurry, and 32a and 32b are green ceramic sheets. Patent applicant Murata Manufacturing Co., Ltd. Representative Patent attorney Yama 1) Yoshito

Claims (1)

[Claims] Two types of ceramic slurries each made of a different binder system are prepared, and the steps of applying the ceramic slurry and then drying the ceramic slurry are repeated one or more times alternately for the two types of ceramic slurries, thereby forming two layers. A method for manufacturing a ceramic raw sheet, which comprises forming a single ceramic raw sheet in which the above components are integrally laminated on a carrier film.