JPH0570264A - Production of ceramic setter - Google Patents

Abstract

PURPOSE:To produce a ceramic setter taking advantage of a ceramic fiber. CONSTITUTION:A raw liq. contg. a mixture of 3-20wt.% ceramic fiber, 15-60wt.% alumina-based powder, 30-70wt.% of an inorg. low-expansion-coefficient powder having <3X10<-6>/ deg.C thermal expansion coefficient, 0.1-5wt.% magnesia powder and 2-20wt.% of a water-soluble or dispersible high molecular compd. is formed into a sheet. The obtained wet sheet is dried to obtain an original sheet, which is fired at >=1000 deg.C. The obtained ceramic setter has high strength and resistance to heat and spalling and is lightweight, thin and highly economical. Since a large setter is easily produced, the setter is cut, and many small setters are efficiently produced at a time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a ceramic setter (hereinafter, simply referred to as a setter) used when firing a ceramic product such as a ceramic substrate.

[0002]

2. Description of the Related Art Conventionally, when a ceramic or so-called new ceramic product is fired in a firing furnace, a heat-resistant ceramic jig, that is, a setter is used to hold or protect these molded products. ing. This setter is
For example, JP-A-2-30675 and JP-A-2-25
As described in Japanese Patent No. 1088, etc., a raw material such as a heat-resistant inorganic oxide is added with a molding aid or the like, kneaded with water, press-molded, and fired in a firing furnace. Was. Recently, it has become possible to easily use a ceramic fiber having high heat resistance. When this is used, a ceramic product that is light and has high strength can be obtained. Therefore, it has also been used as a raw material for a setter. For example, Japanese Patent Laid-Open No. 63-113294 and Japanese Patent Laid-Open No. 3-12369 describe a setter using a ceramic fiber and a manufacturing method thereof. However, even if ceramic fibers are used as a raw material, press and vibration casting are used for molding the setter before firing, as in the conventional case.

[0003]

A setter having high strength, heat resistance, spalling resistance, lightness, thinness, and high economical efficiency is preferable. It is easily predicted that if ceramic fiber is used as the raw material, a setter superior to the conventional one will be obtained due to its reinforcing effect. However, with molding methods such as pressing and vibration casting, it is difficult to increase the reinforcing effect by arranging many ceramic fibers in the plane direction of the setter whose strength you want to reinforce, and it is not possible to make full use of the characteristics of the ceramic fibers used at break. .. Also, to make large plates,
There are problems such as the need for a large high pressure press.

Therefore, the present inventor has studied a method of manufacturing a setter utilizing the characteristics of the ceramic fiber, and as a result,
The robust and economical method for producing the setter of the present invention has been completed.

[0005]

According to the present invention, a ceramic fiber of 3 to 20% by weight, an alumina powder of 15 to 60% by weight, and a thermal expansion coefficient of 30 to 70% by weight of 3 × 10 ^{-6 are used.}
Papermaking raw material liquid containing a mixture of an inorganic low expansion coefficient powder which does not exceed / C, 0.1 to 5% by weight of magnesia powder, and 2 to 20% by weight of a water-soluble or water-dispersible polymer compound. After that, the obtained wet plate is dried to obtain a fired original plate, and the fired original plate is fired at a high temperature of at least 1000 ° C, which is a method for producing a ceramic setter. The present invention will be described in detail below.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the raw materials used in the ceramic setter manufacturing method of the present invention will be described.

The ceramic fiber is not particularly limited as long as it is an inorganic fiber having a heat resistance of about 1000 ° C. or higher after firing the setter at a temperature of at least about 1000 ° C. In the present invention, it is preferable to use a silica fiber, an alumina fiber, an alumina / silica mixed fiber, a mullite fiber, or the like, which is economically and easily available from the market. In addition to these, oxide-based, carbide-based, nitride-based, etc. ceramic fibers can be used. These ceramic fibers may be polycrystalline fibers or single crystal fibers. Fiber type, length, diameter, etc. can be selected according to the purpose and form of use of the setter. The ceramic fiber used is not limited to one type, and two or more types may be mixed and used. The mixing amount of the ceramic fiber is 3 to 20.
If the amount is less than this, the papermaking difficulty will occur if the amount is less than this, and the strength of the setter will decrease. Become.

The alumina powder preferably contains at least 60% of Al ₂ O ₃ . Examples thereof include alumina powder having an Al ₂ O ₃ purity of more than 90%, powders of mullite, andalusite, sillimanite, etc., or a mixed powder thereof. When the content of alumina is small, the heat resistance is lowered, which is not preferable. The powder has an average particle size not exceeding 500 μm, and particularly preferably 100 μm or less. Average particle size is 5
If it is larger than 00 μm or is extremely irregular,
The strength of the fired setter tends to decrease. The amount of the alumina powder mixed is in the range of 15 to 60% by weight in consideration of the firing temperature during production and the heat resistance of the setter to be obtained.

Examples of the inorganic low expansion coefficient powder having a coefficient of thermal expansion not exceeding 3 × 10 ^-6 / ° C. include yukripite, andalusite, petalite and cordierite.
Among these, those having a coefficient of thermal expansion not ^exceeding 2 × 10 ⁻⁶ / ° C. are preferable, and those having a coefficient of thermal expansion not ^exceeding 1 × 10 ⁻⁶ / ° C. are more preferable. This inorganic low expansion coefficient powder has a function of preventing cracking during firing of the setter and improving spalling resistance of the obtained setter. The average particle size of the inorganic low expansion coefficient powder is
According to the above-mentioned alumina powder.

The magnesia powder may be one that is commercially available for the ceramic industry. The magnesia powder has the effect of promoting sintering. If the addition amount is 0.1 or less, the effect is not recognized, and if it exceeds 5% by weight, low-melting glass is produced, which is not preferable.

The water-soluble or water-dispersible polymer compound is
Mainly used as a binder and a dispersant, for example, polyacrylic acid ester resin or emulsion thereof; polyacrylic acid (salt) resin; polyvinyl alcohol resin; polyvinyl acetate emulsion; ethylene / vinyl acetate copolymer emulsion; methyl cellulose, Examples include cellulose resins such as ethyl cellulose, hydroxymethyl cellulose, carboxymethyl cellulose and the like. The polymer compound is not limited to an organic polymer compound, and an inorganic polymer compound such as a silicon resin may be used, or two or more kinds may be mixed and added. The amount added may be an amount necessary and sufficient for achieving the intended effect, and is usually in the range of 2 to 20% by weight.

In addition, for example, an appropriate amount of a dispersant, a defoaming agent, an anti-settling agent, or the like can be added to assist the dispersion of the ceramic fiber or the alumina powder and facilitate the papermaking.

Next, a method for manufacturing a ceramic setter using these raw materials will be specifically described with reference to examples.

First, the above raw materials are added to water at a predetermined mixing ratio, stirred and mixed to sufficiently disperse or dissolve them to prepare a slurry-form papermaking raw material liquid. The order of addition of the raw materials and the stirring time may be determined depending on the amount and characteristics of the raw materials used.

Next, the papermaking raw material liquid is made into paper. Here, papermaking means that a slurry-shaped papermaking raw material liquid containing a fibrous substance is poured onto a screen, and naturally and / or suction dehydrated from the papermaking raw material liquid through the screen. To produce a wet plate. A well-known continuous papermaking method may be used for very large-scale production, but normally, a screen is placed on the bottom of a shallow frame having a square bottom, and a raw material liquid for papermaking is poured in to perform batch papermaking. There is no particular limitation on the shape or depth of the frame. The mesh size of the screen is preferably about 100 to 300 mesh, but depending on the shape of the ceramic fiber or the like, a mesh size with a smaller mesh size or a larger mesh size may be used. Dehydration is carried out by natural or suction dewatering, but normally, natural dewatering is first carried out so that cracks do not occur in the wet plate, and when almost all the water has flowed out, the degree of vacuum is gradually raised to perform dewatering by suction. If necessary, smooth the surface of the wet plate with a trowel during dehydration. The thickness and size of the wet board are determined by the thickness and size of the target product. However, when the setter manufacturing method of the present invention is used, it is possible to easily manufacture a thin flat plate having a large area, which was difficult by the conventional pressing method or the like. Utilizing this fact, if a large setter is manufactured by the method of the present invention and then cut into a desired size, a small setter can be mass-produced at one time.

The wet plate thus obtained was removed from the frame, air-dried for a while, and then dried in a dryer at 100 to 200 ° C.
Then, heat and dry to obtain a calcined original plate. If the original plate does not crack or break during the drying, another drying method may be used.

The firing original plate is heated to a temperature of at least 1000 ° C. in an ordinary firing furnace and fired to obtain a setter. If necessary, cut this setter to the required size.

The above description is one example of the present invention, and the shape of the setter is often a flat plate, but is not limited to a flat plate. For example, using a cylindrical screen to make a cylindrical wet plate, and drying it using the same procedure as above,
It is also possible to manufacture a cylindrical setter by firing.

[0019]

EXAMPLES Examples of the present invention will be described below, but "parts" in the text mean parts by weight.

Example 1 5 parts of alumina / silica fiber (trade name: Fiber Flux H manufactured by Toshiba Monoflux Co., Ltd.) was well dispersed in 200 parts of water, and commercially available sillimanite powder 4 was added thereto.
3 parts, 43 parts of cordierite powder and 1 part of magnesia powder were added and stirred to disperse. Next, 7 parts of polyacrylic acid emulsion and 1 part of sodium polyacrylate were added and mixed by stirring to prepare a slurry-form papermaking raw material liquid.

This papermaking raw material liquid was applied with a width of 1.5 m and a depth of 1.
It was poured into a papermaking frame in which a 200-mesh screen was attached to the bottom of a frame having a depth of 15 mm and a depth of 15 mm, and was naturally dehydrated until water did not flow out. During this time, I used a trowel to prevent unevenness and cracks on the surface. Next, the papermaking frame was attached to a dehydration / suction frame connected to a vacuum pump, and was gradually sucked and dehydrated from the bottom surface of the papermaking frame to such an extent that the papermaking product was not cracked. At first, the decompression degree was low, and when the water was no longer discharged, the decompression degree was raised, and finally to a decompression degree close to 1 atm to continue dehydration. When no more water came out, the papermaking product, that is, the wet plate was removed from the frame and transferred to a wire mesh table to obtain a wet plate having a thickness of 13 mm.

The wet plate was left to stand in a well-ventilated place for one and a half days to be air-dried, and then heated to 170 ° C. in an electric heating dryer to be dried to obtain a calcined original plate. The fired original plate thus obtained was placed on a carriage and inserted into a roller hearth furnace, and the temperature was raised to 1400 ° C. and held for 40 minutes to obtain a ceramic setter.

The evaluation results of this setter are shown in Table 1.

Example 2 10 parts of amorphous fiber (trade name: Fiber-Flux, manufactured by Toshiba Monoflux Co., Ltd.) was well dispersed in 350 parts of water, and 33 parts of commercially available alumina powder and 46 cordierite powder were added thereto. And 0.6 part of magnesia powder were added and stirred to disperse. Then, as a dispersant, 10 parts of polyvinyl acetate emulsion, hydroxyethyl cellulose 0.
4 parts and a small amount of the defoaming agent were added and mixed with stirring to prepare a slurry-form papermaking raw material liquid.

This was dehydrated, dried and dried in the same manner as in Example 1.
Firing was performed to obtain a setter having a thickness of 14 mm.

Table 1 shows the evaluation results of this setter.

Example 3 After dissolving 6 parts of polyvinyl alcohol in 400 parts of water, a polycrystalline mullite fiber (trade name:
Fibermax Toshiba Monoflux Co., Ltd. 1
7 parts was added and well dispersed. 23.5 parts of commercially available mullite powder, 55 parts of cordierite powder, 0.5 parts of magnesia powder, and a small amount of an antifoaming agent were added, and the mixture was stirred and well dispersed to prepare a slurry-form papermaking raw material liquid. ..

This was dehydrated and dried in the same manner as in Example 1, then heated to 1390 ° C. in a gas furnace and held for about 60 minutes to be fired to obtain a setter having a thickness of 10 mm.

The evaluation results of this setter are shown in Table 1.

[0030]

[Table 1]

[0031]

The setter manufacturing method of the present invention is simple, and if it is used, the characteristics of the ceramic fiber used are fully utilized, the strength is high, and the heat resistance is high.
It is possible to efficiently manufacture a setter that withstands spalling, is light, thin, and has high economical efficiency. Also, since a large setter can be manufactured, it is also possible to cut this and manufacture a large number of small setters at one time.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masayoshi Yoshida 3-18 Terada-cho, Suma-ku, Kobe City, Hyogo Prefecture Kaiki Chemical Industry Co., Ltd.

Claims (1)

[Claims] 1. A ceramic fiber of 3 to 20% by weight,
15 to 60% by weight of alumina powder, 30 to 70% by weight of inorganic low expansion coefficient powder having a coefficient of thermal expansion not exceeding 3 × 10 ⁻⁶ / ° C., 0.1 to 5% by weight of magnesia powder, 2 to
After making a papermaking raw material liquid containing a mixture of 20% by weight of a water-soluble or water-dispersible polymer compound, the obtained wet plate is dried to obtain a baked original plate, and the baked original plate is at least 10
A method for manufacturing a ceramic setter, which comprises firing at a high temperature of 00 ° C.