JP5727345B2 - Method for manufacturing ceramic green tape and ceramic sheet - Google Patents

Description

  The present invention relates to a method for producing a ceramic green tape, and a method for producing a ceramic sheet using the ceramic green tape.

  As a method of manufacturing ceramic sheets, ceramic green sheets and porous spacer sheets are alternately stacked to form a laminate, and a large number of ceramic green sheets are fired at once by placing the laminate in a firing furnace. There is a known method (see, for example, Patent Document 1).

  The ceramic green sheet is punched out of a long ceramic green tape as disclosed in Patent Document 2, for example. For manufacturing the ceramic green tape, for example, a manufacturing apparatus disclosed in Patent Document 3 can be used.

  The manufacturing apparatus disclosed in Patent Document 3 manufactures a ceramic green tape while running a resin film. Specifically, first, a slurry containing ceramic particles is applied onto a resin film fed from a roll, and then the applied slurry is dried to produce a wide ceramic green tape. Thereafter, the resin film is peeled off from the ceramic green tape and wound up. On the other hand, the ceramic green tape from which the resin film has been peeled is slit along the longitudinal direction by a slitter. The narrow ceramic green tape that has been slit is wound up individually.

  Patent Document 4 discloses that a ceramic green tape is slit with a slitter together with a resin film.

JP 2009-215102 A JP 2011-82149 A Japanese Patent Laid-Open No. 9-66512 JP-A-9-216193

  By the way, in the case of a ceramic green tape with high adhesiveness such as zirconia, when the ceramic green tape is wound up alone to form a roll, the surrounding portions are joined to each other. Therefore, it becomes difficult to feed out the ceramic green tape from the roll when punching out the ceramic green sheet. In order to solve this problem, as disclosed in Patent Document 4, it is conceivable to slit the ceramic green tape together with the resin film with a slitter and wind up the ceramic green tape with the resin film.

  However, in such a method, since the resin film is slit from wide to narrow, the resin film cannot be reused.

  In view of such circumstances, an object of the present invention is to provide a method for producing a ceramic green tape capable of preventing the joining of surrounding portions when winding the ceramic green tape and reusing the resin film. . Moreover, this invention aims at providing the manufacturing method of the ceramic sheet using the ceramic green tape obtained by the manufacturing method.

  In order to solve the above-mentioned problems, the method for producing a ceramic green tape of the present invention includes a step of applying a slurry containing ceramic particles on the first resin film while feeding out the first resin film. A step of drying the slurry to produce a ceramic green tape; a step of peeling and winding the first resin film from the ceramic green tape; and the ceramic green tape from which the first resin film has been peeled off. Slitting with a slitter, attaching the second resin film to the slitted ceramic green tape while feeding out the second resin film, and winding the ceramic green tape with the second resin film And a step of taking.

  Moreover, the manufacturing method of the ceramic sheet of this invention is attached to said 2nd resin film from the roll by which said ceramic green tape with said 2nd resin film obtained by the manufacturing method of said ceramic green tape was wound. Removing the second resin film from the ceramic green tape while feeding the ceramic green tape, and punching out a ceramic green sheet having a predetermined shape from the ceramic green tape from which the second resin film has been peeled. The step of alternately stacking the ceramic green sheets and the spacer sheets to form a laminate, and the step of placing the laminate in a firing furnace and firing the ceramic green sheets in the laminate. It is characterized by.

  According to the method for producing a ceramic green tape of the present invention, it is possible to prevent the joining of the surrounding portions when winding the ceramic green tape and to reuse the resin film.

  Further, according to the method for producing a ceramic sheet of the present invention, the ceramic green tape can be satisfactorily delivered from the roll, and the quality of the ceramic sheet can be improved and the storage period can be shortened.

(A) And (b) is a schematic block diagram of the manufacturing apparatus which performs the manufacturing method of the ceramic green tape which concerns on one Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following description relates to an example of the present invention, and the present invention is not limited to these.

  FIG. 1 is a schematic configuration diagram of a manufacturing apparatus 1 that executes a method for manufacturing a ceramic green tape according to an embodiment of the present invention. The manufacturing method of this embodiment includes a coating process, a drying process, a peeling process, a slit process, a bonding process, and a winding process. Furthermore, you may provide a buffer process and a correction process between a slit process and a bonding process as needed. Hereinafter, each step will be described in detail.

(1) Coating process In the coating process, the slurry 30 containing ceramic particles is applied onto the first resin film 2 while feeding the belt-shaped first resin film 2 from the roll 21. The coating method is not particularly limited, and a doctor blade method or a calendar roll method can be used. In this embodiment, the doctor blade method is adopted. Specifically, the slurry is introduced into the coating dam 31 disposed on the resin film guide roller 11, and the film thickness of the slurry 30 to be coated by the doctor blade 32 is defined.

  The material of the ceramic particles is not particularly limited. For example, metal oxides such as aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, cerium oxide, and chromium oxide; cordierite, β-spongeumen, titanic acid Complex oxides such as aluminum, barium titanate, mullite, spinel; metal carbides such as silicon carbide; metal nitrides such as aluminum nitride and boron nitride; transition metal oxides such as nickel oxide and iron oxide; lanthanum manganate and lanthanum Examples thereof include perovskite structure oxides such as cobaltite and lanthanum chromite, and one of them can be selected or a mixture of two or more can be used.

  In particular, when producing a ceramic sheet used as an electrolyte membrane of a fuel cell, zirconia stabilized with yttrium oxide, scandium oxide, cerium oxide, ytterbium oxide or the like as a material of ceramic particles; yttria, samaria, gadria, etc. Doped ceria; lanthanum gallate and lanthanum gallate perovskite structure in which lanthanum or gallium part of lanthanum gallate is substituted with strontium, calcium, barium, magnesium, aluminum, indium, cobalt, iron, nickel, copper, etc. An oxide or the like can be used.

  Moreover, when manufacturing the ceramic sheet | seat utilized as a separator of a fuel cell, an electroconductive material is suitable. For example, lanthanum chromite or a lanthanum chromite perovskite structure oxide in which a part of lanthanum or chromium of lanthanum chromite is replaced with strontium, calcium, nickel, cobalt, aluminum, magnesium, titanium, or the like can be used.

  When manufacturing ceramic sheets that are used as ceramic substrates for electronic components, etc., metal oxides such as aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, cerium oxide; cordierite, beta sponge, titanium Complex oxides such as aluminum oxide, barium titanate, mullite, spinel; metal carbides such as silicon carbide; metal nitride conductive materials such as aluminum nitride and boron nitride, etc. can be used alone or in combination. .

  Among the materials described above, the manufacturing method of the present embodiment is particularly useful when the ceramic particles are zirconia stabilized with yttrium oxide, scandium oxide, cerium oxide, ytterbium oxide, or the like. Alternatively, the ceramic particles may be a mixture of stabilized zirconia powder and other ceramic powders. In this case, the content of the stabilized zirconia powder in the ceramic particles is preferably 95% by mass or more, and more preferably 99% by mass or more.

Stabilized zirconia includes alkaline earth metal oxides such as MgO, CaO, SrO, BaO; Y ₂ O ₃ , La ₂ O ₃ , CeO ₂ , Pr ₂ O ₃ , Nd ₂ O ₃ , Sm ₂ O ₃ , _{eu 2 O 3, Gd 2 O} 3, Tb 2 O 3, Dy 2 O 3, Ho 2 O 3, Er 2 O 3, Yb 2 O 3 rare earth element oxides such _{as; Sc 2 O 3, Bi 2} O 3 Examples thereof include zirconia containing one or more oxides such as In ₂ O ₃ as a stabilizer. Further, as other additives, SiO ₂ , Ge ₂ O ₃ , B ₂ O ₃ , SnO ₂ , Ta ₂ O ₅ , Nb ₂ O _{5 and the} like may be contained. Among them, stabilized zirconia containing scandia or yttria as a stabilizer is preferable in order to ensure a higher level of oxygen ion conductivity and strength and toughness, and in particular, oxygen ion conductivity is more excellent. Therefore, stabilized zirconia containing scandia is preferred.

The average particle size of the ceramic particles is preferably 0.2 μm or more and 0.8 μm or less. Here, the “average particle diameter” refers to the median diameter obtained from the particle size distribution, that is, 50% by volume (D ₅₀ ). When the average particle size is less than 0.2 μm, the viscosity of the slurry increases and it becomes easy to form spots and bubbles on the surface of the ceramic green tape. When it exceeds 0.8 μm, coarse particles appear as spots on the ceramic green tape. This is because streaks are more likely to appear. The average particle diameter is more preferably 0.30 μm or more and 0.70 μm or less, and further preferably 0.40 μm or more and 0.60 μm or less.

  The slurry 30 includes a solvent, a binder, a plasticizer, a dispersant, and the like in addition to the ceramic particles. When preparing the slurry 30, it is preferable to concentrate and degas after mixing the above-mentioned elements. The viscosity of the slurry 30 is preferably 1900 to 2700 Pa · s, more preferably 2100 to 2500 Pa · s at 25 ° C.

  Solvents used for preparing the slurry 30 include alcohols such as methanol, ethanol, 2-propanol, 1-butanol and 1-hexanol; ketones such as acetone and 2-butanone; aliphatics such as pentane, hexane and heptane. Hydrocarbons; aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene; acetic acid esters such as methyl acetate, ethyl acetate, and butyl acetate can be exemplified, and these are appropriately selected and used. These solvents can be used alone or in combination of two or more.

  The binder used for the preparation of the slurry 30 is not particularly limited as long as it can be removed by being decomposed or burned by firing at the time of manufacturing a subsequent ceramic sheet, and a conventionally known organic binder can be used. It can be appropriately selected and used. Examples of organic binders include ethylene copolymers, styrene copolymers, acrylate and methacrylate copolymers, vinyl acetate copolymers, maleic acid copolymers, polyvinyl butyral resins, vinyl acetal resins, Examples thereof include vinyl formal resins, vinyl alcohol resins, waxes, and celluloses such as ethyl cellulose.

  The ratio of the binder in the slurry 30 is preferably 15 parts by mass or more and 25 parts by mass or less with respect to 100 parts by mass of the ceramic particles. When the binder ratio is less than 15 parts by mass, the ceramic green tape after coating and drying may crack or crack. When it exceeds 25 parts by mass, the ceramic green tape becomes soft and punched. This is because it becomes difficult to perform operations in the processes such as, and it is easy to cause deformation. The ratio of the binder is more preferably 16 parts by mass or more and 23 parts by mass or less, and further preferably 17 parts by mass or more and 20 parts by mass or less.

  The plasticizer used for the preparation of the slurry 30 is added to impart flexibility to the ceramic green tape. Examples of the plasticizer include a low molecular plasticizer, a co-oligomer plasticizer, and a high molecular plasticizer. Examples of the low molecular plasticizer include phthalic acid esters such as dibutyl phthalate and dioctyl phthalate.

  The dispersant used for the preparation of the slurry 30 is added to suppress the sedimentation of the ceramic particles in the slurry. Examples of the dispersant include anionic dispersants such as KD-4, 9 manufactured by Uniqema, Floren G700 and G900 manufactured by Kyoei Chemical Industry, BYK-220S manufactured by BYK Chemie, and KD-1 manufactured by Uniqema. Cationic dispersants such as DOPA-22, Disperbyk 108, 112, 116 manufactured by Big Chemie; Nonionic dispersants such as Naraxel FM-1D manufactured by Daicel, B246SF manufactured by Uniqema, NC-500 manufactured by Kyoei Chemical Co., Ltd. Can be mentioned. Furthermore, a surfactant, an antifoaming agent, etc. can be added as needed. It is desirable that the amount of water in the slurry is as small as possible.

  Although resin which comprises the 1st resin film 2 is not specifically limited, For example, it is preferable to use a polyethylene terephthalate (PET). The width | variety of the 1st resin film 2 is 500-1500 mm, for example.

  The traveling speed of the first resin film 2 is preferably 0.25 to 1.5 m / min, and more preferably 0.35 to 1.0 m / min.

(2) Drying step In the drying step, the coated slurry 30 is dried to produce the ceramic green tape 3A. The method for drying the slurry 30 is not particularly limited, but in the present embodiment, the drying process is performed by passing the first resin film 2 coated with the slurry 30 through the three drying chambers. The three drying chambers are heated to a higher temperature than the natural drying chamber 41 that circulates room temperature air, the first heating and drying chamber 42 that circulates air heated to a relatively high temperature, and the first heating and drying chamber 42. It is the 2nd heating drying chamber 43 which circulates the performed air. 75-110 degreeC is preferable and the temperature of the air which circulates through the 1st heat drying chamber 42 has more preferable 85-100 degreeC. 85-120 degreeC is preferable and the temperature of the air which circulates through the 2nd heat drying chamber 43 has more preferable 95-110 degreeC.

(3) Peeling Step In the peeling step, the first resin film 2 is peeled off from the ceramic green tape 3A on the guide roller 12, and the peeled first resin film 2 is wound around the roll 22. The roll 22 is obtained by winding the first resin film 2 around a core material, and the core material is rotated by a motor (not shown).

(4) Slit process In the slit process, the slitter 5 slits the ceramic green tape 3A from which the first resin film 2 has been peeled off along its longitudinal direction. The slitters 5 are arranged at predetermined intervals in the width direction of the ceramic green tape 3A. The predetermined interval defines the width of the narrow ceramic green tape to be finally obtained, and is, for example, 50 to 300 mm.

  In the slitting process, it is preferable to cut off both ears of the ceramic green tape 3A. In this case, the slitter 5 is installed by the number obtained by adding 1 to the number of narrow ceramic green tapes to be finally obtained. For example, to obtain three narrow ceramic green tapes, four slitters 5 are installed.

  The slitter 5 is composed of a pair of upper and lower rotary blades made of, for example, high speed steel. In order to perform the slit stably, it is preferable to install a support plate made of, for example, stainless steel that supports the ceramic green tape before and after the slitter 5. Moreover, it is preferable to install a heater for heating the ceramic green tape on the upstream side of the slitter 5 so that burrs and debris do not appear on the slit surface of the ceramic green tape.

(5) Buffer process In this embodiment, while the coating process, the drying process, the peeling process, and the slit process described above are continuously performed, the bonding process and the winding process described later are intermittently performed at predetermined intervals. Is called. In the buffer process, the slitted ceramic green tape 3B is stored while applying tension to the ceramic green tape 3B during the predetermined interval.

  Specifically, a tension roller 14 is disposed between the pair of green tape guide rollers 13 and 15. The tension roller 14 is configured to move up and down with a stroke capable of absorbing a distance obtained by applying the traveling speed of the first resin film 2 to the predetermined interval. With this configuration, even when the conveyor 6 described later is stopped, a certain tension is applied to the ceramic green tape 3A due to the weight of the tension roller 14, and slitting by the slitter 5 is continuously performed.

(6) Correcting process In the correcting process, the displacement of the slit ceramic green tape 3B with respect to the second resin film 7 described later is corrected. In the present embodiment, the correction process is performed using the conveyor 6 that conveys the slit ceramic green tape 3B. The conveyor 6 may be a belt type or a roller type. The conveyor 6 operates in synchronization with the transfer by the moving chuck 83 of the bonding apparatus 8 described later.

  Specifically, when the position of the ceramic green tape 3B in the width direction is detected by the optical sensor 61 and the ceramic green tape 3B slit with respect to the second resin film 7 is displaced by a predetermined amount or more, the deviation is detected. The conveyor 6 is moved in a direction orthogonal to the conveying direction so as to cancel out.

(7) Bonding step In the bonding step, the second resin film 7 is bonded to the slitted ceramic green tape 3B while feeding the belt-shaped second resin film 7 from the roll 71.

  Although the resin which comprises the 2nd resin film 7 is not specifically limited, For example, it is preferable to use PET. The width | variety of the 2nd resin film 7 is smaller than the width | variety of the 1st resin film 2, for example, is 54-304 mm.

  The method of bonding the second resin film 7 to the slit ceramic green tape 3B is not particularly limited, but in the present embodiment, the bonding is performed using the bonding apparatus 8. Specifically, first, the second resin film 7 is superposed on the ceramic green tape 3 </ b> B slit using the resin film guide roller 16, and this composite is supplied to the bonding apparatus 8.

  The laminating device 8 includes an endless belt 81 stretched between a pair of rollers 82, and a moving chuck 83 that sandwiches and transfers the composite together with the endless belt 81.

  The moving chuck 83 is configured to be movable between a first position on the upstream side and a second position on the downstream side, clamps the complex at the first position, moves to the second position, and moves the complex. Release the body clamp. The moving speed of the moving chuck 83 is naturally higher than the traveling speed of the first resin film 2 in order to send out all the ceramic green tape 3B stored in the buffer process.

  The moving chuck 83 is provided with a roller 84 that rolls on the ceramic green tape 3B in the composite when the moving chuck 83 returns from the second position to the first position. The roller 84 is made of rubber, for example. Since the air trapped between the slit ceramic green tape 3B and the second resin film 7 is pushed out by the roller 84, they can be brought into close contact with each other without any slack.

  Further, the bonding apparatus 8 releases the clamp of the composite to prevent the composite from running backward due to its own weight when the tension roller 14 is not clamped by the mobile chuck 83. And a fixed chuck 85 that clamps the complex until it is clamped again.

  Note that if the second resin film 7 is simply bonded to the slit ceramic green tape 3B, the roller 84 is not always necessary, and the bonding can be performed only by the moving chuck 84 and the fixed chuck 85. .

(8) Winding step In the winding step, the ceramic green tape 3B with the second resin film 7 is wound around the roll 9. The roll 9 is obtained by winding the ceramic green tape 3B with the second resin film 7 around the core material, and the core material is rotated by a motor (not shown). The drive of the motor is controlled using a torque limiter so that excessive tension is not applied to the ceramic green tape 3B with the second resin film 7.

  Winding around the roll 9 may be performed below the conveyance surface (belt surface of the bonding apparatus 8) of the ceramic green tape 3B with the second resin film 7, but is performed above the conveyance surface. Are preferred. In this case, as shown in FIG. 1, it is preferable that a presser roller 17 is disposed on the upstream side of the roll 9.

  Through the above steps, the roll 9 around which the ceramic green tape 3B with the second resin film 7 is wound is obtained. In this roll 9, when the ceramic green tape 3B with the second resin film 7 is unwound, the ceramic green tape 3B with the second resin film 7 has no warp in the width direction, and the subsequent punching of the ceramic green sheet is performed. It can be done well.

  As disclosed in Patent Document 4, when the ceramic green tape is slit together with the resin film with a slitter and the ceramic green sheet with the resin film is wound up, A warp in the width direction is observed on the green tape. This is because the shrinkage when the slurry is dried is restrained by the resin film, and the tensile stress in the width direction remains on the ceramic green tape.

  On the other hand, in the manufacturing method of this embodiment, since the resin film is once peeled from the ceramic green tape, the ceramic green tape contracts in the width direction and no tensile stress remains. Therefore, the ceramic green tape can be prevented from warping in the width direction.

<Manufacture of ceramic sheets>
In order to manufacture a ceramic sheet using the roll 9, the second resin film 7 is first peeled from the ceramic green tape 3B while the ceramic green tape 3B with the second resin film 7 is fed from the roll 9. . Next, a ceramic green sheet having a predetermined shape is punched from the ceramic green tape 3B from which the second resin film 7 has been peeled off. The shape of the ceramic green sheet to be punched is not particularly limited, and may be any of a circle, an ellipse, a rectangle, a rectangle with rounded corners, and the like.

  Thereafter, the punched ceramic green sheets and separately prepared spacer sheets are alternately stacked to form a laminate. At this time, it is preferable to spray the powder which suppresses those joining on the surface of a ceramic green sheet and a spacer sheet. Finally, the formed laminate is put in a firing furnace, and the ceramic green sheet in the laminate is fired. Thereby, a ceramic sheet is obtained.

<Modification>
The manufacturing method of this invention should just include a coating process, a drying process, a peeling process, a slit process, a bonding process, and a winding process among the processes mentioned above, and various deformation | transformation are possible from the said embodiment. . Further, the specific method in each step is not necessarily the same as that in the above embodiment.

  For example, in order to continuously perform the bonding step and the winding step, a pair of rollers that sandwich the ceramic green tape 3B with the second resin film 7 may be employed instead of the bonding device 8. With this configuration, the buffer process is unnecessary. Furthermore, since the production line is shortened, the correction process may be omitted.

  Further, for example, if a reverse rotation prevention mechanism is provided on the green tape guide roller 15 on the downstream side of the tension roller 14, the fixing chuck 85 of the bonding apparatus 8 can be omitted.

  Further, the correction process may be performed by using a transport roller instead of the conveyor 6 and tilting the transport roller with respect to the traveling direction of the ceramic green tape 3B in plan view.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not restrict | limited to these Examples at all.

  In this example, the ceramic green tape was manufactured using the manufacturing apparatus 1 shown in FIG.

First, a slurry was prepared as follows. Commercially available 8 mol% yttria stabilized zirconia powder (trade name “TZ-8YS”, manufactured by Tosoh Corporation, average particle size: 0.52 μm, specific surface area: 8.5 m ² / g, hereinafter referred to as 8YSZ) 99.5 Part by mass and alumina powder (trade name “AL-160SG” manufactured by Showa Denko KK) 0.5 part by mass (that is, 100 parts by mass of ceramic particles), toluene / isopropanol mixed liquid as a solvent (toluene / isopropanol mass ratio = 3 / 2) A mixture of 50 parts by mass and 2 parts by mass of a sorbitan fatty acid ester surfactant as a dispersant was mixed while being pulverized using a ball mill. A methacrylate copolymer (number average molecular weight: 100,000, glass transition temperature: −8 ° C., solid content concentration: 50%) as a binder and 15 parts by mass in terms of solid content and dibutyl as a plasticizer are added to the mixture. 3 parts by mass of phthalate was added and further mixed by a ball mill. The obtained mixture was concentrated and degassed, and the viscosity at 25 ° C. was adjusted to 3 Pa · s to obtain a slurry.

  As the first resin film, a PET film having a width of 580 mm and a thickness of 188 μm, coated with a release agent on one side, was applied at a speed of 0.35 m / min. Worked. A natural drying chamber that circulates air at a temperature of 35 ° C., a first heating and drying chamber that circulates air at a temperature of 80 ° C., and a second heating and drying chamber that circulates air at a temperature of 100 ° C. A ceramic green tape with a PET film having a thickness of 250 μm was obtained.

  After peeling the PET film from the ceramic green tape, the ceramic green tape was slit with slitters arranged at intervals of 180 mm to obtain a ceramic green tape having a width of 180 mm.

  Thereafter, as described in the column of the embodiment, a buffer process, a correction process, and a bonding process were performed. In the bonding step, a PET film having a width of 164 mm and a thickness of 125 μm was used as the second resin film. Finally, a winding process was performed to obtain a roll on which a ceramic green tape with a PET film was wound.

DESCRIPTION OF SYMBOLS 1 Manufacturing apparatus 2 1st resin film 3A, 3B Ceramic green tape 5 Slitter 6 Conveyor 7 2nd resin film 8 Laminating apparatus 81 Endless belt 82 Roller 83 Moving chuck 84 Roller 85 Fixed chuck 9 Roll

Claims (3)

Applying a slurry containing ceramic particles on the first resin film while paying out the first resin film;
Drying the coated slurry to produce a ceramic green tape;
Peeling and winding the first resin film from the ceramic green tape;
Slitting the ceramic green tape from which the first resin film has been peeled off with a slitter;
Bonding the second resin film to the ceramic green tape slit while feeding out the second resin film;
Winding the ceramic green tape with the second resin film;
A method for producing a ceramic green tape, comprising:   The method for producing a ceramic green tape according to claim 1, wherein a width of the second resin film is smaller than a width of the first resin film. The ceramic green tape with the second resin film is obtained from a roll around which the ceramic green tape with the second resin film obtained by the method for producing a ceramic green tape according to claim 1 or 2 is wound. Peeling the second resin film from the ceramic green tape while unwinding,
A step of punching out a ceramic green sheet of a predetermined shape from the ceramic green tape from which the second resin film has been peeled;
A step of alternately stacking the ceramic green sheets and the spacer sheets to form a laminate;
Placing the laminate in a firing furnace and firing the ceramic green sheet in the laminate;
A method for producing a ceramic sheet, comprising:

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