JPH10249824A - Apparatus and method for manufacturing green sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and method for manufacturing a green sheet for forming the sheet having no pore. SOLUTION: The apparatus for manufacturing a green sheet comprises an ultrasonic vibrator 9 disposed at a bottom of a blade coater 1, a shutter 10 disposed immediately before a doctor blade, and a groove provided on a sheet molding base 8. The shutter 10 is vertically movable and can hold a carrier sheet 4 between the shutter 10 and the groove disposed under the shutter 10. The shutter 10 is closed, and slurry 2 is cast in the coater 1. The slurry 2 is ultrasonically vibrated by the vibrator 9 and sufficiently deaerated. Thereafter, the shutter 10 is opened, and when the sheet 4 is moved, the sheet 10 of a thickness corresponding to a gap between the blade and the sheet 4 is continuously formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for manufacturing green sheets used for manufacturing multilayer ceramic electronic components such as multilayer ceramic capacitors and multilayer ceramic piezoelectric elements.

[0002]

2. Description of the Related Art Conventionally, a green sheet used for a multilayer ceramic capacitor, a multilayer ceramic piezoelectric element or the like is generally formed by an apparatus as shown in FIG. 1, and the green sheet is manufactured by the following steps. ing.

[0003] First, a predetermined amount of a sol slurry 2 is injected into a blade coater 1 having both a slurry tank and a doctor blade. Next, as shown by the arrow P in the drawing, the carrier sheet 4 on which the release agent has been applied in advance is
The carrier is moved from the left to the right from the carrier sheet supply unit 3 via the sheet forming table 8, and is placed on the carrier sheet 4 with a thickness substantially corresponding to the gap between the doctor blade 1 a of the blade coater 1 and the carrier sheet 4. Undried green sheets 5 are continuously formed.

[0004] Thereafter, the solvent in the green sheet 5 is evaporated and dried in a drying furnace 6 using hot air blowing or infrared irradiation, and the carrier sheet winding section 7 forms the green sheet 5 on the surface thereof. Wind up 4.

[0005]

By the way, in the above-mentioned conventional method, in order to release gas in the slurry, the slurry is defoamed by a vacuum drying defoaming machine before being injected into a blade coater. However, at the stage of injecting the slurry thus defoamed into the blade coater, it is extremely common that air is involved in the slurry, so that pores remain in the obtained green sheet, which may deteriorate the material yield. There was an issue.

[0006] The present invention has been made in view of the problems of the prior art, and has as its object the following.
It is an object of the present invention to provide a green sheet manufacturing apparatus and a manufacturing method capable of producing a green sheet having no pores.

[0007]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventor has found that by providing an ultrasonic vibrator in a slurry tank and further providing a shutter near a doctor blade, the present inventors have found that the present invention has been made satisfactory. It has been found that the degassed slurry can be supplied to the doctor blade, and the above object can be achieved, and the present invention has been completed.

That is, the green sheet manufacturing apparatus of the present invention comprises a slurry tank, a doctor blade, a carrier sheet, a sheet supply section for supplying the carrier sheet, and a sheet for winding the carrier sheet from the sheet supply section. A green sheet including a winding unit, a sheet forming table on which the carrier sheet is placed, and holding the carrier sheet flat, and a drying furnace disposed between the doctor blade and the sheet winding unit. In manufacturing equipment,
An openable and closable shutter capable of controlling slurry supply is provided near the doctor blade, and an ultrasonic oscillator is provided in the slurry tank.

In the method for producing a green sheet according to the present invention, when producing a green sheet from a ceramic slurry as a raw material by a doctor blade method, the above-mentioned production apparatus is used, and the shutter is opened and closed to the above-mentioned carrier sheet by opening and closing the shutter. Is characterized by controlling the supply of

[0010]

According to the present invention, when pouring the slurry into the slurry tank, the shutter is closed, and then the ultrasonic vibrator installed in the tank is operated to remove the gas in the slurry and to sufficiently degas the slurry. Later, the shutter can be opened to create a sheet according to the gap between the blade and the carrier sheet. Therefore, there is no hole or the like in which a bubble is missing in the obtained green sheet, and a sound green sheet can be obtained.

Further, in the present invention, a groove can be provided in a sheet forming table for holding a carrier sheet, and a part of the carrier sheet is pressed into a concave portion of the groove by a lower end portion of the shutter. Can be closed. With this configuration, the effect of blocking the slurry from the doctor blade can be improved. In this case, in the open state of the shutter, the carrier sheet moves under tension, so that the movement of the carrier sheet is not hindered by the groove of the sheet forming table.

Further, in the present invention, the slurry tank and the doctor blade can be formed integrally, and a part of the slurry tank, specifically, a wall on the drying furnace side of this tank is used as a doctor blade. Immediately before or immediately after the doctor blade, the shutter can be installed adjacent to the shutter. According to this configuration, the number of members to be used can be reduced to save space, etc., and the slurry that has been sufficiently degassed can be instantaneously supplied to the doctor blade. The possibility of involving air can be reduced.

The installation location of the above-mentioned ultrasonic vibrator is as follows.
It is sufficient if it is in the slurry tank, but it is preferable to dispose the ultrasonic vibrator over the entire bottom of the slurry tank because vibration is applied to as wide a range of slurry as possible and bubbles are discharged upward. Thereby, it is possible to improve the deaeration performance of the slurry.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 2 is a sectional view showing an embodiment of the green sheet manufacturing apparatus of the present invention. The description of the common parts with the above-described conventional apparatus will be omitted. This manufacturing apparatus is disposed immediately before the ultrasonic vibrator 9 disposed on the blade coater 1 also functioning as a slurry tank and the doctor blade 1a. Shutter 10
And a groove 8 a provided in the molding table 8 as shown in FIGS. 3 and 4.

The shutter 10 is formed so as to be able to move up and down, so that the carrier sheet 4 can be held between the shutter 10 and a groove 8a provided below the shutter. The ultrasonic vibrator 9 is disposed at the bottom of the blade coater 1 to improve the degassing / defoaming effect of the slurry 2.

Next, a method of manufacturing a green sheet using this manufacturing apparatus will be described. First, a predetermined amount of the slurry 2 is injected into the blade coater 1. At this stage, the hard rubber shutter 10 is kept in a closed state. In this state, a part of the carrier sheet 4 is pressed by the lower end of the shutter 10 as shown in a partially enlarged sectional view of FIG. This part is in a state pressed into the recess of the groove 8a.

Next, the ultrasonic vibrator 9 is operated to perform ultrasonic vibration, and the slurry 2 is sufficiently degassed. Thereafter, the shutter 10 is opened to bring the shutter 10 into an open state as shown in a partially enlarged sectional view of FIG.
Is tensioned by the sheet winding section 7, so that the press-fitted sheet portion becomes flat as described above, and the movement of the carrier sheet 4 is not hindered.

In such an open state, the carrier sheet 4 on which the release agent has been applied in advance is moved from the left to the right as shown by the arrow P in FIG. On the carrier sheet 4, undried green sheets 5 having a thickness substantially corresponding to the gap between the doctor blade 1a of the blade coater 1 and the carrier sheet 4 are continuously formed.

Thereafter, the undried green sheet 5 is sent to a drying furnace 6 where the solvent in the green sheet 5 is evaporated and dried by irradiating infrared rays, and the carrier sheet winding section 7 forms the green sheet 5 on the surface. 4 to complete the production of the green sheet. Needless to say, if the degassing and defoaming of the slurry described above and the opening and closing of the shutter are continuously controlled, a green sheet having no holes or the like caused by air bubbles can be efficiently produced.

Next, the material and the like of the main members in the manufacturing apparatus will be described. The shutter 10 can be appropriately selected depending on the type of the carrier sheet 4 and the slurry 2 and the like. However, a material that does not damage the carrier sheet and has corrosion resistance to a slurry solvent and wear resistance to a ceramic material is preferable. Rubber can be exemplified.

Specifically, in the case of a slurry using an organic solvent, the slurry is preferably formed of a fluororesin (PTFE), and a phenol resin can be partially used.
In the case of an aqueous solvent, there is no particular limitation as long as it is rubber, plastic, or the like, but those that absorb water and swell are not preferred.

The shutter hardness is preferably made softer than the carrier sheet so as not to damage the carrier sheet as described above. Since the carrier sheet is often made of a fluororesin, it is equal to or less than the fluororesin. Preferably, it is softened. The pressure resistance of the shutter may be 1 × 10 ⁵ Pa (about 1 atm) or more. Further, as the ultrasonic vibrator 8, any conventionally known ultrasonic vibrator can be used.

Although the present invention has been described in detail with reference to one embodiment, the present invention is not limited to this embodiment, and various modifications can be made within the scope of the disclosure of the present invention. For example, the slurry tank and the doctor blade may be formed separately. In the present embodiment, the shutter 10 is provided inside the blade of the blade coater 1, but the same effect can be obtained by providing the shutter 10 outside the blade.
Further, the shape of the groove 8a is not particularly limited, and may have a semicircular or polygonal cross section.

Also, depending on the type of slurry, it is difficult to entrain the air when pouring it into the slurry tank, and even if it is entrained, it can be defoamed by leaving it a little, and in such a case, the ultrasonic vibrator is used. It is not necessary to operate it, and furthermore, it is also possible to eliminate the ultrasonic vibrator from the green sheet manufacturing apparatus.

[0025]

As described above, according to the present invention, since the ultrasonic vibrator is provided in the slurry tank and the shutter is provided near the doctor blade, a green sheet without pores can be produced. An apparatus and a method for manufacturing a green sheet can be provided.
That is, the shutter is closed and the slurry is injected, and then the green sheet can be formed by opening the shutter after sufficiently deaerated by the vibration of the ultrasonic vibrator, thereby forming a sheet caused by bubbles in the slurry. A green sheet free of holes, defects and the like can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of a conventional green sheet manufacturing apparatus.

FIG. 2 is a cross-sectional view showing one embodiment of a green sheet manufacturing apparatus of the present invention.

FIG. 3 is a partially enlarged sectional view showing a shutter closed state of the manufacturing apparatus of FIG. 2;

FIG. 4 is a partially enlarged sectional view showing a shutter open state of the manufacturing apparatus of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Blade coater 1a Blade (doctor blade) 2 Slurry 3 Carrier sheet supply part 4 Carrier sheet 5 Green sheet 6 Drying furnace 7 Carrier sheet winding part 8 Sheet forming table 8a Shutter groove 9 Ultrasonic vibrator 10 Shutter

Claims (8)

[Claims] 1. A slurry tank, a doctor blade, a carrier sheet, a sheet supply section for supplying the carrier sheet, a sheet winding section for winding the carrier sheet from the sheet supply section, and a carrier sheet on which the carrier sheet is mounted. Is placed, in a green sheet manufacturing apparatus including a sheet forming table that holds the carrier sheet flat, and a drying furnace disposed between the doctor blade and the sheet take-up unit, the vicinity of the doctor blade A green sheet manufacturing apparatus comprising: an openable and closable shutter capable of controlling slurry supply; and an ultrasonic vibrator provided in the slurry tank. 2. The green sheet manufacturing according to claim 1, wherein the doctor blade is formed integrally with the slurry tank, and the shutter is disposed immediately before or immediately after the doctor blade. apparatus. 3. The sheet forming table has a groove, and the shutter is closed by pressing a part of the carrier sheet into a recess of the groove. The green sheet manufacturing apparatus according to the above. 4. The green sheet manufacturing apparatus according to claim 1, wherein the ultrasonic vibrator is provided over the entire bottom of the slurry tank. 5. The shutter according to claim 1, wherein the shutter has corrosion resistance and abrasion resistance to slurry, and has a hardness that does not damage the carrier sheet. The green sheet manufacturing apparatus according to the above section. 6. A method for producing a green sheet from a ceramic slurry as a raw material by a doctor blade method, wherein the carrier of the slurry is opened and closed by opening and closing the shutter using the production apparatus according to claim 1. A method for producing a green sheet, comprising controlling supply to a sheet. 7. The method for producing a green sheet according to claim 6, wherein the slurry is degassed and defoamed by the ultrasonic vibrator, and then the shutter is opened to form a green sheet. 8. The method for producing a green sheet according to claim 6, wherein the degassing and defoaming of the slurry and the opening and closing of the shutter are continuously controlled.