JPH0345564A - Production of ceramic plate - Google Patents

Abstract

PURPOSE:To produce a ceramic plate free from warpage and undulation by preparing raw ceramic sheet by a doctor-blade method, bonding a pair of the raw sheets with a specific adhesive, calcining the obtained green sheet and dividing the calcined sheet along the bonded part. CONSTITUTION:A raw ceramic sheet plate 7b produced by doctor blade method is placed on another raw ceramic sheet plate 7a in such a manner as to overlap the upper surfaces or the lower surfaces of both raw sheets with each other. Both raw sheets 7a and 7b are bonded together using an adhesive containing a solvent different from the binder existing in the raw ceramic sheets 7a, 7b. The green sheet 8 produced by the above process is calcined to obtain a calcined sheet 13 (the green sheet 8 is wound around a core 11 in the form of a coil and calcined after extracting the core 11). The calcined sheet 13 is divided along the bonded part to obtain a pair or ceramic plates 14a, 14b.

Description

DETAILED DESCRIPTION OF THE INVENTION ``Industrial Application Field'' The present invention relates to a method for producing ceramics used as substrate materials and the like.

"Prior Art" Conventionally, plate-shaped ceramics used as substrates in the field of electronics and the like have been mainly manufactured by the doctor blade method.

In this method, 1. A I203, Z ro! A solvent or water is added to ceramic powder such as, and necessary chemicals such as a dispersing agent, binder, and plasticizer are added and mixed as appropriate to create a homogeneous slurry. This slurry is transferred to a carrier with a doctor blade. An unsintered ceramic sheet (green sheet) is produced by coating the material on a tape to a predetermined thickness and then drying with hot air or infrared rays to volatilize the solvent or water and solidify it. Next, the obtained green sheet is cut into a predetermined size and heated and fired in a firing furnace to produce a ceramic plate.

``Problems to be Solved by the Invention'' However, when a green sheet formed by the doctor blade method is fired singly to improve the component distribution in the thickness direction, edges will occur as shown in fired ceramic plate A shown in Figure 9. This results in a warped state.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for manufacturing a flat ceramic plate without warping or waviness.

"Means for Solving the Problems" As a means for solving the above problems, the present invention provides a method for placing another raw ceramic sheet on top of a plate-shaped raw ceramic sheet produced by a doctor blade method. The green sheets are placed so that their bottom surfaces overlap each other, and then both green sheets are bonded together using an adhesive containing a solvent of a different type from the binder contained in the green ceramic sheet to form a green sheet. Then, the green sheet was fired to obtain a fired sheet, and then this fired sheet was divided from the bonded portion to produce two ceramic plates.

Hereinafter, an example of the method of the present invention will be explained in detail with reference to the drawings.

Ceramics used in the method of the present invention include:
Materials with high toughness and plasticity are preferably used,
A particularly suitable ceramic is Zr01 with Y vo
3. These are ceramic materials such as partially stabilized zirconia (PSZ), silicon nitride, and sialon in which stabilizers such as M go , CaO, and Ceo z are dissolved.

In order to produce a ceramic plate using such a ceramic material, first, a solvent and chemicals necessary for producing a raw sheet such as a plasticizer, a binder, and a dispersant are added to and mixed with the ceramic powder. A slip 1 is produced as a homogeneous slurry, and a green sheet is produced by a doctor blade method.

FIG. 1 is a diagram showing an example of a doctor blade device suitably used for producing a green sheet. This doctor blade device includes a supply port 2 for supplying a slip l in the form of a slurry containing a ceramic material, a belt 3 for conveying the slip l formed in a thin plate shape, and a belt 3 for transporting the thin plate from the supply port 2 onto the belt 3. The belt 3 includes a doctor blade 4 for drawing out the slip 1 in a shape, and a dryer 5 for heating and drying the thin plate-like slip 1 on the belt 3.

To produce a raw sheet using this doctor blade device, the slip 1 is put into the supply port 2, and the belt 3 is moved by rotating the two rollers 6a and 8b for driving the belt 3. The slip l is pulled out in a thin plate form from the supply port 2 onto the belt 3 by the doctor blade 4, is conveyed by the belt 3, enters the dryer 5, and is heated and dried in the dryer 5 to form a rubber-like raw sheet. It becomes 7a. After drying, the raw material 7a is separated from the belt 3 and wound around a winding roller.

The dimensions of the raw sheet produced in this way are limited in the width direction by the sheet forming width of the doctor blade device;
The length can be set to a certain arbitrary length. The thickness of the green sheet is appropriately set in consideration of the mechanical strength after firing, but is usually 10 to 1000μ.
m (Coil shape↓liAI-IJIM-, 6n
n,,-)L-4-2mQ/eQ±1 Then, as shown in FIG. 2, the long raw sheet 7 produced as described above
Another green sheet 7b is placed on top a so that the top surfaces or bottom surfaces of both sheets overlap, and an adhesive is applied between these green sheets 7a and 7b to bond them together to form a green sheet 8. do. At the time of this bonding, as shown in FIG. 3, adhesive is applied between the two green sheets 7a and 7b, and then the sheets are placed between a pair of pressure rollers 9 and 9, and the sheets are bonded together by pressure. is preferred.

The adhesive used to bond the two raw sheets 7a, 7b is an adhesive containing a solvent of a different type from the binder contained in the raw sheets 7a, 7b. , 7b is an organic binder such as polyvinyl alcohol, a water-soluble adhesive such as an acrylic adhesive or a starch adhesive is used.

If the binder contained in the raw sheets 7a, 7b is aqueous, an organic solvent adhesive such as a polyvinyl alcohol adhesive or a chloroprene adhesive is used.

Non + 5-fs"It A nn1- --
+k A I-L: elemental/Tj II)
Green sheet 8 obtained by l'l Δ↓Hese
is wound in a coil around a conic core 11 while attaching a release material IO to one surface thereof. This mold release material 10 is made of a material that does not show adhesion or reactivity to the ceramic material used during firing, and when zirconia is used as the ceramic material, the main component is alumina powder or boron powder. A sheet (or a powder may be sprayed and sprinkled) is preferably used.

Next, the green sheet 8 wound around the core 11 is placed on the setter 12, and then the core 11 is gently removed. Next, this is placed in a firing furnace and fired under the usual firing conditions for the ceramic material used.

The firing conditions are appropriately set depending on the type of ceramic material used. For example, when using zirconia as a ceramic material, the firing conditions are as follows:
Preferable conditions are 0 to 1600°C and a firing time of about 30 minutes to several hours.

By this firing, a long coil-shaped fired sheet 13 shown in FIG. 5 is produced.

This fired notebook 13 is in a state in which two thin coil-shaped ceramic plates 14a, 14b can be easily separated from the bonded portion of the two green sheets 7a, 7b.

Then, an extremely thin piece of metal or a knife is inserted into the bonded part of the fired sheet 13, and the two ceramic plates 14a, 14 are bonded together.
By dividing the two parts into b and gently separating them, the sixth
As shown in the figure, two long coiled ceramic plates 1
4a and 14b are obtained.

The ceramic plates 14a, 14b can be made partially flat by increasing the diameter of the core 11 and taking advantage of the toughness of the ceramic material. Additionally, circuits, electrodes, and other components can be mounted using this portion.

In the method for manufacturing a ceramic plate according to this example, two green sheets 7a and 7 produced by the doctor blade method are used.
b are bonded together using an adhesive containing a solvent of a different type from the binder to form a green sheet 8, and then the green sheet 8 is fired, whereby the fired sheet I3 is separated from the bonded portion into two ceramic sheets. Plate 14a, 1
It can be divided into 4b.

Here, the relationship between the adhesive used to form the green sheet 8 and the state of the bonded portion will be explained with reference to FIGS. 7 and 8. When bonding the two green sheets 7a and 7b, Adhesive 1 containing a solvent similar to the binder in the sheet
5a, as shown in FIG.
The raw material particles 1 in the raw sheets 7a and 7b are separated by the solvent in a.
The binder that connects the particles 6 melts on the surface, and the raw material particles 16 diffuse into the layer of adhesive 15a. Due to the diffusion of the raw material particles 16, the raw material particles in the adhesive layer 15a become dense enough to be sintered, and when this green sheet is fired, 2
A thick ceramic plate made up of two green sheets is obtained.

On the other hand, if adhesive 15b containing a solvent different from the binder is used to bond raw sheets 7a and 7b,
As shown in the figure, the adhesive 15 is
Diffusion of raw material particles 16 into the b layer is suppressed. Therefore, even when this green sheet is fired, the two sheets do not sinter together, and the two sheets are sintered as separate pieces, so that they can be easily peeled off from the bonded part after firing. Two thin ceramic plates are obtained.

In the method for manufacturing a ceramic plate according to the example described above, a green sheet 8 is formed by bonding two green sheets 7a and 7b so that their upper surfaces or lower surfaces overlap each other, and this green sheet 8 is fired. By doing so, the forces that cause each sheet to warp during firing (non-uniformity in the thickness direction) are offset, and a flat ceramic plate without warp or waviness can be manufactured. Furthermore, since this warping occurs at an early stage of sintering, even if the sheets are temporarily attached with an adhesive containing a solvent of a different type than the binder, the adhesive strength is sufficiently strong and each sheet will not peel off.

Further, although it is difficult to handle a thin green sheet, it becomes easier to handle it by pasting two green sheets 7a and 7b together. For example, when producing a long ceramic plate in the form of a coil, the green sheet 8 is placed on the setter 12 and fired, but even in this case, one green sheet would collapse, but two green sheets 7a and 7b The green sheet 8 made by pasting together can be wound into a coil to stand upright, and can be fired without warping or waviness. Therefore, it is possible to easily manufacture a thin ceramic plate having a thickness of 50 μm or less.

Furthermore, in the manufacturing method according to this example, a release material lO is added to one side of the green sheet 8, and the green sheet 8 is wound around the core body 11 and formed into a coil shape, and then fired, thereby making it possible to use a conventional firing furnace. A long ceramic plate of arbitrary length can be produced using this method.

In the previous example, the method of the present invention was applied to the production of a coiled ceramic plate, but the method of the present invention
Needless to say, the present invention can also be applied to a method for manufacturing a ceramic plate in which a plate-shaped green sheet is fired without being wound into a coil.

"Example" A ceramic plate was manufactured based on the present invention.

Raw material powder...311101% Y, Zr containing 03
O2 solvent...MEK (methyl ethyl ketone) plasticizer...D-butyl phthalate binder...polyvinyl alcohol dispersant...triolein These raw materials are pulverized and mixed in a ball mill for several tens of hours to form a uniform slurry. Obtained. Next, this slurry was formed into a sheet using a doctor blade method, and then dried with hot air to volatilize and remove the solvent to solidify, and then cut to produce a green sheet with a width of 1 cm, length of 1 meter, and thickness of 50 μm. .

Obtained. Another green sheet was placed on top of the green sheet so that their upper surfaces overlapped, and at this time, acrylic adhesive was applied between both surfaces to adhere the two green sheets to produce a green sheet. Next, a sheet-like release material (mainly composed of alumina powder) is applied to one side of the green sheet.
Width 1c+++, length 1 meter, thickness 150μff1)
was attached and wound around a cylindrical core material with a diameter of 10 cm with the release material on the inside. Next, this was placed on a setter, the core material was gently pulled out, and then placed in a firing furnace for 1500
A firing treatment was performed at ℃ for 1 hour.

After this firing, a thin metal plate is inserted into the bonded part of the fired sheets obtained to temporarily separate the two ceramic plates, and then the two ceramic plates are gently separated to form two long coiled ceramic plates. I got it.

The obtained ceramic plate is very thin (thickness 40 to 5
0 μ so), was uniform, had no warpage, and exhibited good elasticity.

"Effects of the Invention" As explained above, the method for manufacturing a ceramic plate according to the present invention has the following effects.

In the present invention, two green sheets are pasted together so that the top or bottom surfaces of the green sheets overlap each other to form a green sheet, and this is fired, so it is possible to suppress the occurrence of warping or waviness during firing. It is possible to produce ceramic plates without warping or waviness.

In addition, by bonding two raw sheets together with an adhesive containing a binder and a different type of solvent to create a green sheet, and dividing the resulting fired sort into two ceramic plates, we are able to create extremely thin ceramic sheets. Manufacture of the board can be facilitated.

[Brief explanation of drawings]

1 to 6 are diagrams for explaining an example of the method for manufacturing a ceramic plate according to the present invention in the order of steps, and FIG. 1 shows a doctor blade device suitably used to carry out the method of the present invention. A configuration diagram showing an example, Fig. 2 is a perspective view showing a state in which green sheets are pasted together, Fig. 3 is a side view of the same, Fig. 4 is a perspective view showing a state in which green sheets are wound into a coil, and Fig. 5 is a perspective view of the fired sheet, FIG. 6 is a perspective view of the ceramic plate, and FIGS. 7 and 8 are side views for explaining the relationship between the adhesive used to form the green sheet and the state of the bonded part. FIG. 9 is a perspective view showing an example of a state in which warpage occurs in a ceramic plate manufactured by a conventional method. 7 a, 7 b... Raw sheet, 8... Green sheet, 13... Fired sheet, 14a, 14b... Ceramic board, 15b... Adhesive.

Claims (1)

[Claims] Another raw ceramic sheet is placed on the plate-shaped raw ceramic sheet produced by the doctor blade method so that the upper or lower surfaces of both raw ceramic sheets overlap, and Both green sheets are bonded together using an adhesive containing a binder and a solvent of a different type, and then the green sheet is fired to form a fired sheet, and this fired sheet is then separated from the bonded part. A method for manufacturing a ceramic plate, characterized by manufacturing two ceramic plates by dividing the plate.