JPH0818310B2 - Method for manufacturing green ceramic sheet - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a ceramic green sheet, and more particularly to a ceramic green sheet used for a laminated ceramic electronic component such as a laminated ceramic capacitor or a laminated ceramic substrate. It relates to a manufacturing method.

[Prior Art] As a conventional method for manufacturing a monolithic ceramic electronic component,
There is a method in which an internal electrode paste is printed on a ceramic green sheet and dried, and a predetermined number of the ceramic green sheets thus formed are laminated and then press-bonded.

Also, as another method, a method of repeating the process of printing the internal electrode paste on the ceramic green sheet with the carrier film attached, drying it, laminating it by thermocompression bonding and peeling the carrier film is devised. ing.

[Problems to be solved by the invention]

In either method, the ceramic green sheet is a single layer or a single layer formed by the doctor blade method or the like. Therefore, if the ceramic green sheet is made thin to increase the capacity, defects such as pores and pinholes will become apparent in the ceramic green sheet, and the conductive paste as the internal electrode material will penetrate through the defective portion and the lower layer There was a problem that the withstand voltage was lowered and a serious short circuit accident occurred.

In order to solve such a problem, there is a method of interposing a ceramic green sheet (white sheet) having no internal electrode formed between the laminated ceramic green sheet and the internal electrode.

However, although this method can prevent the breakdown voltage and the short circuit accident due to the conduction of the internal electrodes as described above,
Since the dielectric layer (ceramic layer) between the internal electrodes cannot be thinned, it is difficult to increase the capacity, and in order to make it thin, the ceramic green sheet itself must be thinned, and if it is too thin, handling becomes difficult. Furthermore, an expensive carrier film must be used also when producing the above-mentioned white sheet, and therefore the cost becomes high.

Therefore, a main object of the present invention is to provide a method for producing a ceramic green sheet, which allows a ceramic green sheet without defects to be obtained at a lower cost.

[Means for solving problems]

According to the present invention, the steps of preparing two types of ceramic slurries each made of a different binder system, applying the ceramic slurries, and then drying the ceramic slurries are alternately repeated once or more for the two types of ceramic slurries to form two or more layers integrally Is a method for producing a ceramic green sheet, which comprises forming a single ceramic green sheet laminated on a carrier film.

[Action]

Either one of the two types of ceramic slurry is applied onto the carrier film and then dried. Then, the other ceramic slurry is continuously applied onto the dried ceramic green sheet and then dried. If necessary, two kinds of ceramic slurry are applied and dried to obtain one ceramic green sheet having two or more layers laminated on a carrier film.

〔The invention's effect〕

According to the present invention, two or more types of ceramic green sheets are alternately laminated to form one ceramic green sheet, so that even if there is a defect of pores or pinholes in one layer, it is possible to use other layers. By being covered, the occurrence of defects due to such defects can be reduced as much as possible.

Further, since it is not necessary to make the thickness of each ceramic green sheet extremely thin, the handling becomes easy, and the swelling (leaching of the conductive paste and the deformation of the ceramic green sheet due to it) which is a problem when the thickness is thin is mitigated. To be done.

Further, the consumption amount of the carrier film can be suppressed as compared with the case where the white sheet is used, so high cost can be avoided.

Furthermore, when ceramic slurries of the same binder are applied in a laminated manner, swelling tends to occur, but since the binder systems of the ceramic slurries are made different, swelling is avoided.

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

〔Example〕

1A and 1B are illustrative views showing an embodiment of the present invention. In the manufacturing apparatus 10 of this embodiment, the carrier film 16 is provided between the feeding roller 12 and the winding roller 14.
Cross over. As the carrier film 16, one having one surface subjected to a mold release treatment, for example, a polyethylene film coated with a silicone resin or the like can be used.

Then, the carrier film 16 delivered from the delivery roller 12 is pulled by the four tension rollers 18 to form a flat portion 20, and is guided to the winding roller 14.

Below the flat portion 20 of the carrier film 16, containers 24a and 24b for storing the ceramic slurries 22a and 22b therein are provided so that they can be moved up and down, respectively.

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

Then, above the containers 24a and 24b, there are arranged gravure rollers 26a and 26b for lifting the ceramic slurries 22a and 22b, supplying them to the flat portion 20, and performing so-called gravure transfer. Also, the gravure roller 26a and
Blades 28a and 28b for adjusting the passing amount of the lifted ceramic slurry 22a and 22b are arranged near the 26b, respectively.

A dryer 30 is arranged on the carrier path of the carrier film 16, and the dryer 30 includes the gravure roller 26a.
The ceramic slurry 22a and 22b respectively applied by 26 and 26b are dried to obtain ceramic green sheets 32a and 32b.

First, as shown in FIG. 1, the position of the container 24a is adjusted and the gravure roller 26a is arranged in the vicinity of the flat portion 20 so that the ceramic slurry 22a can be applied to the carrier film 16.

Then, by rotating the gravure roller 26a in the direction of arrow 34, the ceramic slurry 22a in the container 24a is applied to the lower surface of the carrier film 16 delivered from the delivery roller 12 with a predetermined thickness. The thickness of the applied ceramic slurry 22a depends on the size of the gap between the gravure roller 26a and the tip of the blade 28a. Therefore, the blade 28a is configured so that the gap can be adjusted and set arbitrarily.

The ceramic slurry 22a applied to the lower surface of the carrier film 16 is brought to the above-mentioned dryer 30 as the carrier film 16 is transferred, and dried there to become a ceramic green sheet 32a. The one-layer ceramic green sheet 32a thus formed is taken up by the take-up roller 14 together with the carrier film 16, and the first step is completed.

Then, it moves to the second process. As shown in Figure 1B, 1
In the second step, the winding roller 14 wound with the ceramic green sheet 32a (and the carrier film 16) is set on the delivery side, and the empty delivery roller 12 is set on the delivery side. Also, this time ceramic raw sheet 32a
The position of the container 24b is adjusted so that the gravure roller 26b is arranged near the flat portion 20 and the container 24a is moved away so that the ceramic slurry 22b of a type different from that in the previous step can be applied.

Then, similarly to the first time, the ceramic slurry 22b is applied again to the lower surface of the previously formed ceramic green sheet 32a by the gravure roller 26b with a predetermined thickness and dried to form the second ceramic green sheet 32b. To do.

According to an experiment conducted by the inventors of the present invention, the ceramic slurry
When the binder systems of 22a and 22b were the same, when the green ceramic sheet of the second layer was formed in the step of FIG. 1B, swelling occurred between that and the first layer. On the other hand, such swelling did not occur when the binder system or solvent system of the two ceramic slurries was made different according to the present invention.

If it is desired to further increase the number of laminated layers, the above steps may be alternately repeated to form a plurality of ceramic green sheets 32a and 32b, respectively, as shown in FIG.

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

The type of ceramic slurry is not limited to two as in the above-described embodiment, and three or more types of ceramic slurry are used to stack the ceramic green sheets 32a, 32b and 32c as shown in FIG. You may.

Further, in the above-mentioned embodiment, the carrier film 16 is set to 1
Although the film is wound and reset in each step, the carrier film 16 may be endless so that it can be continuously repeated without removing or resetting the roller.

Further, the method of applying the ceramic slurry is not limited to the method of gravure transfer as in the above-mentioned embodiment, and other methods such as a doctor blade method may be used.

[Brief description of drawings]

FIGS. 1A and 1B are schematic views showing an embodiment of the present invention, FIG. 1A shows a manufacturing process of a ceramic green sheet of the first layer, and FIG. 1B shows a ceramic green sheet of the second layer. A manufacturing process is shown. FIG. 2 is an illustrative view showing a state in which two types of green ceramic sheets are laminated in multiple layers. FIG. 3 is an illustrative view showing a state in which three types of ceramic green sheets are laminated. In the figure, 16 is a carrier film, 22a and 22b are ceramic slurry, and 32a and 32b are ceramic green sheets.

Claims (1)

[Claims] 1. A step of preparing two types of ceramic slurries each made of a different binder system, applying the ceramic slurries, and then drying them is repeated once or more alternately for the two types of the ceramic slurries to form two or more layers. A method for producing a ceramic green sheet, which comprises forming, on a carrier film, a single ceramic green sheet in which the above are integrally laminated.