JPS5948995A - Method of producing 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] [Technical field to which the invention pertains] The present invention relates to a method of forming a green ceramic substrate.

More specifically, the present invention relates to a method for homogeneously and continuously forming green sheets into ceramic substrates by firing.

[Prior art and its problems]

One widely used method for producing green sheets is the doctor blade method.

For example, the main raw material component such as alumina, a solvent,
Plasticizers, resins, etc. are added and stirred to create a slurry (slip), and this slip is placed on a carrier film with a mechanical part called a doctor blade that adjusts the thickness of the slip. Dry the slip part in an oven,
This is a method of forming an unfired sheet (green sheet).

The green sheet manufacturing method using this doctor blade method will be explained with reference to FIG.

FIG. 1 is a schematic explanatory diagram of a green sheet manufacturing method that is currently widely used.

The slip 1 consisting of alumina main raw material, solvent, plasticizer, resin, etc. is injected into the doctor grade chamber, and a green sheet with a thickness mainly controlled by the doctor grade 2 is deposited on the carrier film 3. 6 is obtained. The carrier film 3 is rolled in the direction of the arrow M by the carrier film roll 4. While the slip on the carrier film 3 passes through the drying oven 5, some of the solvent etc. is splashed off, and when it leaves the drying oven 5 it becomes a flexible green sheet 6 with a partial thickness. , career
It is peeled off from the film 3 and wound up with only the green sheet.

Here, a conventional problem has been that the green sheet 6 coming out of the drying oven 5 is difficult to separate from the carrier film 3.

To make it easier to peel off, one side of the carrier film 30, that is, the side that comes into contact with the green sheet, is coated with
For example, a silicone film etc. is attached, but about 1
After about 0 uses, the 71 pattern disappears, causing the problem that the green sheet 6 and the rear film 3 are difficult to separate.

For this reason, the following methods have conventionally been used to separate the green sheet from the carrier film.

First, the feeding speed of the carrier film 3 is set to a low speed, and the drying of the slip 1 in the drying oven 5 is carried out slowly over a long period of time. In this method, it is possible to reduce the rotation speed of the carrier film roll 4 up to a certain speed, but there is a certain limit due to mechanical design values and it cannot be lowered below. Therefore, the furnace becomes longer and larger.

Second, there is a method of increasing the overall length of the drying oven 5 and gradually drying the slip 1, but this also makes it easy to vary the speed if a fixed device is used. isn't it. Particularly in the recent trend of small-volume, high-quality electronic components, it is desirable that equipment be as compact as possible and able to meet various demands. I have an older sister.

On the other hand, in order to facilitate the separation of the Green 9 sheet 6 and the carrier film, a method of increasing the sensitivity in the drying oven 5 and scattering the solvent, etc. in the slip 1 relatively quickly is effective to some extent; Such a method often generates air bubbles in the slip 1 or between the slip 1 and the carrier film 3, making it impossible to obtain a homogeneous green sheet 6.

These carrier film 3 and green sheet 6
The problem of difficulty in peeling off from the slip becomes more pronounced as the particle size of the main raw materials, additives, etc. in the slip becomes smaller, and it is difficult to manufacture products with small particle sizes.

[Purpose of the invention]

As mentioned above, it is an object of the present invention to provide a method that allows easy and reliable separation of a green sheet from a carrier film coming out of a drying oven even if the particle size of the slip main raw material etc. becomes small. purpose.

SUMMARY OF THE INVENTION The above-mentioned problems could be solved by providing a cooling device near the outlet 5 of the drying oven 5. Book, What is a quenching device?
It has many openings, and the air inside the holes is green.
The spray is applied over the entire surface of the sheet 6, carrier, and film 3.

Good peeling between the green sheet and the carrier film became possible over the entire raw material particle size within a practical range.

〔Effect of the invention〕

The present invention has greatly improved the production efficiency of re-lean sheets. In other words, in the conventional case where peeling was difficult, the gear rear film was generally first lowered in speed and fed slowly to gradually dry the slip, but the present invention By using forced cooling in the process, it is now possible to perform peeling reliably without reducing speed, greatly improving production efficiency. At the same time, in the past, even when the speed was lowered, some green sheets were incompletely peeled and the yield was low, but the present invention has significantly improved the yield.

According to the present invention, the length of the drying oven could be shortened.

The length of doctor grade molding equipment is 80-90% of that.
However, the fact that this drying oven can be shortened has a great effect in terms of installation space, cost, etc.

The present invention increases the service life of the carrier film. Conventionally, if used for 10 times, the silicone film on the carrier film would peel off from the carrier film, and if used for longer than that, there was a problem that the green sheet would become difficult to peel off from the carrier film. However, according to the present invention, it can now be used up to 20 times, which is twice as long as the conventional method.

[Embodiments of the invention]

(Example 1) 92% aluminum oxide, 5% silicic anhydride, 1.5% magnesium oxide, and 1.5% calcium oxide were wet-ground and mixed using a vibration mill to an average particle size of 10μ, and then dried into powder. I got it. Add ilF to this powder in the following proportions.
The slip was adjusted by adding 9 parts of fat and a plasticizer.

Alumina powder 100 parts Polyvinyl butyral resin 5 parts Trichlorethylene 20 parts n-butanol 1O
N Tetrachlorethylene 8#TBP
2 # As shown in FIG. 2, the slip thus obtained is injected into the doctor blade 2 as slip 1, the height of the doctor blade 2 and the feeding speed of the carrier film 3 are adjusted, and the drying oven 5 is heated. The thickness of the green sheet 6 that comes out is 0.5 mm.

The drying oven has a total length of 10 m, uses polyester film as the carrier film, and has a feed speed of 400 m/min.
When the maximum temperature of the drying oven 5 is set to 120°C, here, as shown in Fig. 3, a forcing plate is provided facing the surfaces of the rubber sheet 6 and the carrier film 3, in contact with the drying oven outlet Q. The quenching device 7 blows air for o, im', ' minutes. As a result, all the green sheets were peeled off uniformly from the carrier film with a yield of υ100% and a predetermined 0.5
A product with a thickness of mm was obtained.

The carrier film used in this manner withstood 14 consecutive uses. In addition, if forced quenching is not used, set 5.
It has been experimentally determined that a yield reduction of 0% occurs.

(Example 2) Alumina@Song having the same composition as in Example 1 was ground and mixed to have an average particle size of 1.7 μm, and the slip was adjusted in the same ratio as in Example 1 using the dried product.

A green sheet was prepared from the slip obtained in this way under the same conditions as in Example 1. There, it was placed in contact with the outlet of the drying oven 1 and as shown in FIG. 3, a clean sheet 6 and a carrier film 3. Forced quenching device installed opposite
7, 0.05m3/only on the green note side
A lot of air blew out. As a result, all green sheets are peeled off uniformly from the carrier film, resulting in lower yields.
At 100%, the specified thickness of 0.5 mm is 100%.

The carrier film used once in this manner withstood 20 consecutive uses.

If the product is not rapidly cooled, 30% of the products will be defective.

Further, although the quenching device uses a method of blowing air, a cooling water bath may be provided and the green sheet and carrier film may be passed through the cooling water bath.

Furthermore, the intended purpose of the present invention can be achieved by simply removing either the green sheet or the carrier film.

[Brief explanation of drawings]

FIG. 1 is a side view of a conventional green sheet manufacturing apparatus, and FIGS. 2 and 3 are a side view and a top view showing a part of the apparatus in cross section according to the green sheet manufacturing method of the present invention. 7... Cooling device

Claims (3)

[Claims] (1) In the process of obtaining ceramic green sheets using a doctor blade forming device, a quenching device is installed at the outlet of the drying oven to rapidly cool the green sheets and carrier film after leaving the drying oven. A method for manufacturing a green sheet characterized by: (2) A method using air as the quenching medium at the outlet of the drying oven. (3) A method for producing a sheet at the outlet of a drying oven using air as a quenching medium.