JPH05294741A - Ceramic sintering insert sheet and production of fired ceramic - Google Patents

Abstract

PURPOSE:To fire a ceramic compact pierced with a small hole such as a through-hole in multiple stages without causing clogging due to scattering of powder and dust and without roughening the sintered compact because of uneven scattering and to easily and separately recover the sintered compacts. CONSTITUTION:A ceramic sintering insert sheet layer consists of a mixture of the heat-resistant powder which is not sintered when a ceramic compact is sintered and an org. binder which is adhesive when heated and not adhesive at ordinary temp. The layer is provided free-to-transfer on a supporting sheet to constitute a ceramic insert sheet. The insert sheet is transferred and adhesively bonded to a ceramic green sheet and punched, and the green sheet are laminated through the insert sheet side and sintered. As a result, the ceramic compact is punched with the insert sheet layer bonded to the compact.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is intended to intervene for the purpose of preventing binding when multi-stage firing of a ceramic molded body having through holes and the like, and the formed fired bodies can be easily collected individually. The present invention relates to an insert sheet for firing ceramics.

[0002]

2. Description of the Related Art Conventionally, when a ceramic molded body having small holes such as through-holes is fired in multiple stages, the ceramic molded bodies are bound to each other or between the ceramic molded body and a firing table thereof. A method has been known in which an inorganic powder such as alumina or aluminum nitride is interspersed so as to prevent individual recovery.

However, there has been a problem that the sprayed powder enters the small holes and is clogged, and the powder cannot be removed even by a powder removing process such as blasting. In addition, there is a problem of dust during powder spraying, and unevenness in spraying tends to cause irregularities such as warpage and swelling on the formed and fired body.

[0004]

DISCLOSURE OF THE INVENTION The present invention is directed to a ceramic molded body provided with small holes such as through holes without the problems of clogging and dust due to powder spraying and unevenness of the formed and fired body due to uneven spraying. It is an object of the present invention to develop a method for producing a fired ceramic, which can perform multi-stage firing and can easily collect formed fired bodies individually.

[0005]

According to the present invention, an interleaving sheet layer made of a mixture of a heat resistant powder that is not fired during firing of a ceramic molded body and an organic binder that is heat-adhesive and does not adhere at room temperature is provided on a support sheet. After the ceramic firing interposing sheet characterized by being provided so that it can be transferred to, and the interposing sheet layer in the ceramic firing interposing sheet is transferred and adhered to the ceramic green sheet, and punched by punching. It is intended to provide a method for producing a fired ceramic, which is characterized in that the ceramic green sheets are stacked with the interposing sheet layer side interposed therebetween and fired.

[0006]

In the above-mentioned ceramic firing interposing sheet, the interposing sheet layer on the supporting sheet can be adhered to the ceramic molded body with sufficient strength by a thermal transfer method, etc. Non-arrival. Therefore, it is possible to easily perform a punching process such as through holes with the interposing sheet layer adhered to the ceramic molded body by a punching method, thereby avoiding the problem of clogging. Further, when the ceramic molded bodies are laminated, the position can be easily corrected without causing surface destruction. Even if an inorganic powder having an adhesive force such as carboxymethyl cellulose is wet-coated by a spray method or the like, the powder has insufficient fixing force and cannot withstand the punching process by punching and falls off during punching.

Further, the powder is evenly distributed by the sheet system,
In addition, it is possible to arrange the layer thickness with good uniformity, avoid dust problems due to powder dispersion, unevenness of the formed fired body due to uneven dispersion, improve the flatness of the formed fired body, and avoid warp correction. it can. Further, the amount of powder applied can be reduced and can be easily removed after firing, and the processing time can be shortened. As a result of the above, it is possible to stably form the target fired body having excellent surface smoothness and dimensional accuracy, and it is possible to easily individually collect the fired body.

[0008]

Examples of constituent elements of the invention: The interposing sheet for firing ceramics of the present invention comprises an interposing sheet layer transferably provided on a supporting sheet. The interposing sheet layer is formed by molding a mixture of a heat resistant powder that is not fired during firing of the ceramic molded body and an organic binder that is heat-adhesive and non-adhesive at room temperature into a sheet form.

As the heat resistant powder that is not fired during firing of the ceramic molded body, an appropriate powder made of ceramic or metal that does not melt at the firing temperature may be used. Generally, the same kind as the ceramic molded body to be fired, such as alumina,
Powder composed of zirconia, aluminum nitride, silicon nitride, silicon carbide, barium trititanate, etc. is used, and a larger grain is used than the ceramic forming the compact so as not to react (bond) with the ceramic compact. .. Generally, the particle size of the heat resistant powder that can be preferably used is 5 to 100 μm, especially 20 to 40 μm based on the average particle size from the viewpoints of preventing binding and deformation of the fired body and preventing surface damage.

As the organic binder, those which are weakly adhesive or non-adhesive and non-adhesive at room temperature, exhibit strong adhesiveness by heating and disappear by thermal decomposition or the like during firing are used. Generally, rubber-based, acrylic-based, vinyl alkyl ether-based base polymers used for hot-melt type pressure-sensitive adhesives, etc., to which a tackifier is added, if necessary, are used.

Examples of the base polymer which can be preferably used from the viewpoint of burnout property include natural rubber and synthetic rubbers of the same type, butyl rubber, polyisoprene rubber, styrene / butadiene rubber, styrene / isoprene / styrene block copolymer rubber, styrene. Examples thereof include rubber-based polymers such as butadiene / styrene block copolymer rubbers, acrylic ester-based polymers containing an alkyl ester of acrylic acid or methacrylic acid as a component. In particular, when firing is performed in a non-oxidizing atmosphere, it is preferable to use a substance that does not easily carbonize during thermal decomposition, such as an acrylic ester-based polymer containing an alkyl ester of methacrylic acid as a component.

Examples of the tackifier include resins such as terpene resin, rosin, hydrogenated rosin or glycerin ester thereof, coumarone indene resin, terpene phenol resin, alkylphenol resin, aliphatic petroleum resin and aromatic petroleum resin. It is preferably used.

A preferred organic binder has a peel adhesion strength (180 degree peeling, peeling speed 300 mm / min) at room temperature to the ceramic molded body of 10 g / 20 mm or less, and particularly 3 g / 20.
mm or less, below the softening start temperature of the ceramic molded body,
In particular, it activates at 40 to 100 ° C and develops a strong adhesive force, which is 20 g / 20 mm or more with respect to the ceramic molded body, especially 200
It can be thermally transferred with a peeling adhesive force of g / 20 mm or more.

As the supporting sheet, for example, an appropriate one known as a separator for an adhesive sheet can be used. In general, polyester, polyethylene, plastic films such as polypropylene, kraft paper, paper such as glassine paper, thin foils such as metal foils are coated on one side with a release agent such as silicone compounds, long-chain alkyl compounds, and fluorine compounds, or Those processed on both sides are used.

The intercalation sheet for ceramic firing is formed by a suitable method such as a gravure roll coater method or a doctor blade method using a mixture of one or more kinds of heat resistant powder and a solvent such as an organic binder. It can be performed by an appropriate method such as a method of solid coating on the support sheet.
In that case, it is preferable that the mixture of the heat-resistant powder and the organic binder is as uniform as possible in order to prevent the smoothness of the formed fired body due to the aggregation or segregation of the heat-resistant powder. When forming the interposing sheet, appropriate additives such as a deflocculant or dispersant, a plasticizer, a wetting agent, a release agent, and a defoaming agent may be added if necessary.

The thickness of the interposing sheet layer provided on the support sheet may be appropriately determined. Generally, 10-200μ
m, especially 20 to 50 μm. If the thickness is less than 10 μm, the heat adhesion may be poor. The content of the heat resistant powder in the interposing sheet layer depends on the binding preventive property of the fired body,
From the point of preventing the ceramic molded body from cracking during firing due to heat adhesiveness and excessive content of organic binder,
0.1 to ²⁰ g / m ² is preferable, and 0.2 to 1 g / m ² is particularly preferable.

The interposing sheet layer provided on the supporting sheet can be adhered to the adherend by a thermal transfer method such as a heating and pressing treatment, and when it is adhered to various ceramic compacts and fired. It is possible to interpose the ceramic molded body so as not to bind to another ceramic molded body or a firing table.

Therefore, the interposing sheet layer is, for example, between a ceramic molded body formed into a sheet form and the firing table, between ceramic molded bodies arranged on the firing table, between laminated ceramic molded bodies, and the like. The ceramic molded body can be thermally transferred and intervened at an appropriate place where the ceramic molded body may be bound. It is also possible to stack the ceramic molded bodies via the interposing sheet layer and then heat the ceramic molded bodies to a temperature at which the organic binder is activated to bond the stacked ceramic molded bodies to fix the stacked state. The fixing has an advantage in that when the ceramic molded body is handled as a laminated body, positional deviation at that time can be prevented.

In the manufacturing method of the present invention, the interposing sheet layer in the above-mentioned intercalating sheet for ceramic firing is transferred and adhered to the ceramic green sheet, punched by punching, and then the ceramic green sheet is inserted into the interposing sheet layer. It is stacked through the sides and fired to obtain a fired ceramic.

For the punching process, an appropriate method such as a punching die may be adopted. Although the holes to be formed are arbitrary, the present invention forms holes, for example, through holes, which easily cause clogging due to the powder and are difficult to remove the clogging, and especially those having a diameter of 5 mm or less, particularly 1 mm or less. Can be used advantageously.

The firing treatment of a ceramic molded body such as a green sheet obtained by transferring and adhering the interposing sheet layer can be appropriately performed under the conditions suitable for the ceramic molded body. In addition to the air, the firing atmosphere is arbitrary such as a nitrogen atmosphere, a vacuum atmosphere, and a reducing atmosphere.

Upon firing, the organic binder in the interposing sheet layer disappears due to gasification and the like, which escapes through the space formed by the heat-resistant powder and disappears, and the heat-resistant powder remains unfired and left as a spacer. And prevents the ceramic molded body from binding. Thereby, the individual recovery of the formed fired body is easily achieved.

[0023]

According to the present invention, the ceramic molded body can be punched by punching with the interposing sheet layer adhered, and the ceramic molded bodies are stacked and fired without causing clogging of the formed holes. It can be treated and the obtained fired body can be easily collected individually.

Further, based on the room temperature non-adhesive interleaving sheet layer,
It is possible to easily correct a stacking deviation without causing surface destruction of the ceramic molded body, and it is possible to easily stack the ceramic molded body through an automatic laminating line or the like. Furthermore, it can be laid evenly, the amount of powder applied can be reduced, it can be easily removed after firing and the processing time can be shortened, the flatness of the fired body can be improved by warping prevention, and the need for warp correction can be avoided. It is possible to stably form a target fired body having excellent accuracy.

[0025]

【Example】

Example 1 A xylene solution containing 30 parts of polymethacrylate having a glass transition point of 20 ° C. (parts by weight;
3 parts of spherical fused alumina powder of μm was added and mixed uniformly, and the uniform dispersion was applied by a doctor blade method onto a separator made of glassine paper with a thickness of 70 μm treated with a silicone release agent and dried. To obtain an interposing sheet for ceramic firing having an interposing sheet layer having a thickness of 30 μm. The interposing sheet layer has excellent thickness uniformity, the organic binder content is 30 g / m ² , and the heat resistant powder content is 1
It was g / m ² .

Next, the interleaving sheet layer in the above-mentioned ceramic firing interposing sheet was formed into a tape body made of a 96% alumina green sheet having a thickness of 0.8 mm and a width of 100 mm.
After heat transfer at 00 ° C and cooling to room temperature, the separator is peeled off and a through hole with a diameter of 0.1 mm is formed using an 80 mm square punching die having a predetermined number of through hole forming pins. Are sequentially stacked on the firing table with an interposing seal layer between them, and the stacking deviation is corrected to 1600 ° C.
Was fired for 2 hours to obtain a fired ceramic.

Example 2 An intercalation sheet for ceramic firing was obtained in the same manner as in Example 1 except that crushed fused alumina powder having an average particle size of 20 μm was used as the heat resistant powder, and a fired ceramic was obtained using the sheet.

Comparative Example To an aqueous solution containing 1 part of carboxymethyl cellulose, 3 parts of spherical fused alumina powder having an average particle size of 30 μm was added and uniformly mixed, and the uniform dispersion was prepared from a 96% alumina green sheet by a roll coating method. Thickness 0.8m
m, 100 mm wide, apply evenly on the tape and dry,
After forming through holes in the tape body according to Example 1, ten sheets were stacked and fired according to Example 1 to obtain a fired ceramic.

Evaluation test Individual recoverability (presence or absence of binding), surface smoothness The individual recoverability (presence or absence of binding) and the surface smoothness of the laminated alumina fired tapes obtained in Examples and Comparative Examples were evaluated. Examined. The results are shown in Table 1.

[Table 1] The slightly poor individual recoverability in the comparative examples in the table was due to the fact that there was a binding part and the peeling could not be carried out smoothly, and the poor surface smoothness was due to the occurrence of surface breakage or unevenness.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tatsushi Yasuda 1-2 1-2 Shimohozumi, Ibaraki-shi, Osaka Prefecture Nitto Denko Corporation (72) Inventor Yoshio Kuramoto 1-2 1-2 Shimohozumi, Ibaraki-shi, Osaka Issue Nitto Denko Corporation

Claims (2)

[Claims] 1. An interleaving sheet layer made of a mixture of a heat resistant powder that is not fired during firing of a ceramic molded body and an organic binder that is heat-adhesive and does not adhere at room temperature is transferably provided on a support sheet. An interposer sheet for firing ceramics. 2. An intercalating sheet layer of the intercalating sheet for ceramic firing according to claim 1 is transferred and adhered to a ceramic green sheet, and after punching processing by punching, the ceramic green sheet is placed on the intercalating sheet layer side. A method for producing a fired ceramic, characterized by stacking and firing the same through.