JP6368093B2 - Green laminate, method for producing green laminate, and method for producing fired laminate - Google Patents

Description

  The present invention relates to a green sheet, a green laminate, a method for producing a green laminate, and a method for producing a fired laminate. In this specification, “green” refers to the state before firing.

  Conventionally, a green sheet (green tape) is prepared by molding and solidifying a slurry containing inorganic powder, a dispersion medium, and a binder, and the prepared green sheet is adhered and laminated on a substrate. A method of obtaining a fired body and firing the obtained green laminate to obtain a fired laminate is widely known (for example, see Patent Document 1).

  In the above document, when laminating a green sheet on a substrate, it is proposed to use a sticky (self-adhesive) green sheet to adhere (fix) the green sheet on the substrate. doing. Thereby, a green sheet can be adhere | attached (fixed) on a board | substrate, without utilizing an adhesive agent etc.

Japanese Patent No. 3498308

  Since the present inventor adheres and laminates a relatively thick green sheet (for example, a thickness of 100 μm or more and 1000 μm or less) on a substrate, “create a green sheet having adhesiveness (self-adhesive) at room temperature” Then, we are studying “adhesion and lamination of this green sheet on a substrate at room temperature”.

  This “green sheet having adhesiveness at normal temperature” has “manual handling by humans (so-called“ handling property ”is good)”, “adequate adhesion to the substrate at normal temperature”, In addition, it is required at least to “shrink securely during subsequent firing”. As a result of various researches and experiments, the present inventor has found a method for producing a green laminate that can satisfy the above requirements. In addition, “reliably firing” means that the shape of the fired body is maintained by “neck formation” or “grain growth” resulting from contact between powders after firing. .

  The method for producing a green laminate according to the present invention is as follows. “The first inorganic powder, the dispersion medium, and a slurry containing a binder are molded and solidified to produce the green sheet having adhesiveness at room temperature. The green laminate is obtained by adhering and laminating a sticky green sheet on the substrate at room temperature. The first inorganic powder is typically ceramic powder, but may be metal powder or “mixed powder of ceramic powder and metal powder”.

  A feature of this manufacturing method is that the binder contains a material having a glass transition point of 20 ° C. or higher and 48 ° C. or lower, and the entire green sheet (including the first inorganic powder, the dispersion medium, the binder, and pores). The volume ratio of the binder (hereinafter referred to as “binder volume ratio”) is 20% by volume or more and 60% by volume or less (in a dry state). The thickness of the green sheet is preferably 100 μm or more and 1000 μm or less (in a dry state), and the weight average molecular weight of the binder is preferably 8000 or more and 1 million or less. In the present specification, the “pore” refers to a space existing in an object regardless of whether it is before firing (green body) or after firing (fired body).

  In order to satisfy the above requirements, the present inventor paid attention to the glass transition point of the binder and the volume ratio of the binder. And this inventor is the said request | requirement that the glass transition point of the said binder is 20 degreeC or more and 48 degrees C or less, and the volume ratio of a binder is 20 volume% or more and 60 volume% or less (in a dry state). It has been found that it can be satisfied (details will be described later).

  A green laminate is obtained by adhering and laminating the adhesive green sheet on the “substrate containing the second inorganic powder” at room temperature using the production method according to the present invention. Here, the substrate may be a green body or a fired body. The entire substrate may be porous or dense. Further, only a part of the substrate may have a different structure. Specifically, for example, the surface of the substrate may be dense and the inside of the substrate may be porous.

  When the substrate is “a dense fired body containing the second inorganic powder”, the green laminate is fired to form “the above dense fired body containing the second inorganic powder” A fired laminated body in which the “porous fired film containing the first inorganic powder” is laminated can be obtained. In this case, the porosity of the “porous fired film containing the first inorganic powder” is 30% by volume or more and 60% by volume or less, and the porosity of the “dense fired body containing the second inorganic powder”. Is preferably 10% by volume or less. The second inorganic powder is also typically a ceramic powder, like the first inorganic powder, but may be a metal powder. In addition, the second inorganic powder may have the same composition and microstructure as the first inorganic powder, or may have a different composition or microstructure from the first inorganic powder.

  The green sheet used in the method for manufacturing a green laminate according to the present invention is “a green sheet including a first inorganic powder and a binder, and the binder has a glass transition point of 20”. It can be described as a “green sheet having adhesiveness at room temperature, containing a substance at a temperature of from 0 ° C. to 48 ° C., and having a volume ratio of 20% by volume to 60% by volume of the binder relative to the whole green sheet”. .

  By the way, in general, when the green sheet is bonded / laminated on the curved surface of the substrate as compared with the case where the green sheet is bonded / laminated on the plane of the substrate, after the baking, the “obtained by baking the green sheet” Cracks and peeling are likely to occur in the “fired film”. The greater the thickness of the green sheet (the precursor of the fired film) relative to the radius of curvature of the curved surface of the substrate, the easier the cracks and delamination occur.

  In this regard, when the inventor uses the above-described green sheet according to the present invention, even if the green sheet (the precursor of the fired film) is relatively thick with respect to the radius of curvature of the curved surface of the substrate, the crack and peeling It was found that is difficult to occur. Specifically, when the thickness of the green sheet is t (μm), the radius of curvature of the curved surface of the substrate is R (μm), and the glass transition point of the binder is Tg (K (Kelvin)). When the relationship of 2.9 (R / Tg) ≦ t ≦ 225 (R / Tg) is established, it has been found that the cracks and peeling are difficult to occur (details will be described later).

1 is an overall perspective view of a fired laminate according to an embodiment of the present invention. It is 2-2 sectional drawing of FIG. It is a perspective view of the whole board | substrate used for preparation of the baking laminated body shown in FIG. FIG. 2 is an overall perspective view of a “green sheet with PET film” used for producing the fired laminate shown in FIG. 1. It is the perspective view which showed the mode at the time of sticking a green sheet on the upper surface of a board | substrate. It is the perspective view which showed the green laminated body by which the "green sheet with PET film" was affixed on the upper surface of the board | substrate. It is the perspective view which showed a mode that a PET film was peeled in the state shown in FIG. It is the perspective view which showed the green laminated body obtained by peeling PET film. It is a perspective view corresponding to FIG. 1 of the baking laminated body which concerns on the modification of embodiment of this invention. FIG. 10 is a sectional view taken along the line 10-10 in FIG. 9; It is the perspective view which showed the green laminated body which is a laminated body before baking of the baking laminated body shown in FIG. 12 is a cross-sectional view taken along line 12-12 in FIG. It is the graph which showed the relationship between "the curvature radius of the curved surface of a board | substrate, the glass transition point of a binder, and the thickness of a green sheet" and "the presence or absence of a crack" about a comparative example. 6 is a graph showing the relationship between “the radius of curvature of the curved surface of the substrate, the glass transition point of the binder, and the thickness of the green sheet” and “the presence or absence of cracks” in the present embodiment. It is a graph which shows "the area | region where a crack etc. do not generate | occur | produce" obtained by employ | adopting this embodiment which is not obtained in a comparative example.

  Hereinafter, a green sheet according to an embodiment of the present invention, and a method for manufacturing a green laminate and a fired laminate according to an embodiment of the present invention will be described with reference to the drawings.

(Configuration of fired laminate)
1 and 2 show a fired laminate according to an embodiment of the present invention. This laminated body is a fired body composed of a rectangular parallelepiped substrate 10 and a thin rectangular parallelepiped (flat plate) film 20 laminated on the upper surface (plane) of the substrate 10. In this laminate, the film 20 is formed over the entire upper surface of the substrate 10. The width A (y-axis direction), depth B (x-axis direction), and height C (z-axis direction) of the fired laminate are, for example, 10 mm or more and 200 mm or less, 50 mm or more and 500 mm or less, and 1 mm or more and 8 mm or less, respectively. .

  The substrate 10 is a dense fired body made of the second ceramic. The substrate 10 may be porous. As the second ceramic, for example, zirconium oxide, yttrium oxide, magnesium oxide, nickel oxide, iron oxide, copper oxide, or a composite oxide containing one or more of these can be used. “Zirconium oxide” may contain an additive element such as, for example, yttria-stabilized zirconia. The thickness of the substrate 10 is 1 mm or more and 8 mm or less.

  The film 20 is a porous fired film that is thinner than the substrate 10 and made of the first ceramic. As the first ceramic, for example, zirconium oxide, yttrium oxide, magnesium oxide, nickel oxide, iron oxide, copper oxide, or a composite oxide containing one or more of these can be used. “Zirconium oxide” may contain an additive element such as, for example, yttria-stabilized zirconia. The second ceramic is different in composition or microstructure from the first ceramic. Generally, the volumetric shrinkage of ceramics by firing is 1% or more and 70% or less. For this reason, for example, when the thickness of the green sheet that is a precursor of the film 20 is 100 μm or more and 1000 μm or less (in a dry state), the bonding surface (laminated surface, lower surface) of the film 20 in a constrained state The thickness is approximately 30 μm or more and 990 μm or less. The porosity of the film 20 is 30% by volume or more and 60% by volume or less. The average diameter of the pores is 0.2 μm or more and 10 μm or less. Here, the “pore” refers to a space existing in the object, regardless of whether it is before firing (green body) or after firing (fired body).

(Method for producing fired laminate)
Next, a method for manufacturing the fired laminate shown in FIGS. 1 and 2 will be described with reference to FIGS. Hereinafter, in each figure, a member with “g” at the end of the reference sign represents “a state before firing” (green). Further, a molded body in a state before firing is simply referred to as a “molded body”, and a product obtained by firing the “molded body” is referred to as a “fired body”.

  First, as shown in FIG. 3, a substrate 10 is prepared which is a dense rectangular parallelepiped fired body. The substrate 10 is obtained, for example, by molding and solidifying “slurry containing the second ceramic powder, dispersion medium, and binder” into a shape corresponding to the substrate 10 and firing the molded body. As the second ceramic powder, for example, zirconium oxide, yttrium oxide, magnesium oxide, nickel oxide, iron oxide, copper oxide, or a composite oxide containing one or more of these is preferable. The median diameter of this powder is, for example, 0.9 μm or more and 10 μm or less. The porosity of the substrate 10 is 10% by volume or less. “Zirconium oxide” may contain an additive element such as, for example, yttria-stabilized zirconia.

  Examples of the dispersion medium include hydrocarbons (toluene, xylene, solvent naphtha, etc.), ethers (ethylene glycol monoethyl ether, butyl carbitol, butyl carbitol acetate, etc.), alcohols (isopropanol, 1-butanol, ethanol, 2 -Ethylhexanol, terpineol, ethylene glycol, glycerin, etc.), ketones (acetone, methyl ethyl ketone, etc.), esters (butyl acetate, dimethyl glutarate, triacetin, etc.), polybasic acids (glutaric acid, etc.) can be used. In particular, it is preferable to use a “solvent having two or more ester bonds” such as a polybasic acid ester (for example, dimethyl glutarate) or an acid ester of a polyhydric alcohol (for example, triacetin). As the binder, for example, acrylic, butyral, epoxy, or the like can be used alone or in a mixed state. Also, polyols such as isocyanate and ethylene glycol can be used. As a binder (an organic component), a gelling agent (a thermosetting resin that undergoes a reaction by heating) is solidified by a gelation reaction (chemical reaction, for example, a urethane reaction that occurs between an isocyanate and a polyol) like a urethane resin. A material other than a gelling agent (that is, a material that does not solidify by a chemical reaction and solidifies only by drying) may be used.

  Further, as shown in FIG. 4, a green sheet 20 g having a shape corresponding to the film 20 is prepared. That is, the green sheet 20 g is a rectangular parallelepiped shaped body that is thinner than the substrate 10. The thickness of the green sheet 20g is 100 μm or more and 1000 μm or less (in a dry state).

  Since the green sheet 20g is thin and easily deformed, as shown in FIG. 4, it is prepared in a state of being attached to a PET film (hereinafter referred to as “sheet 20g with PET film”). The green sheet 20g may be prepared alone.

  The green sheet 20g is obtained by forming and solidifying a “slurry containing a first ceramic powder, a dispersion medium, and a binder” into a thin plate shape (tape shape) and then cutting it into a shape corresponding to the film 20. Here, “solidification” indicates that the shape of the green body is maintained by volatilization of a dispersion medium or a chemical reaction. This molding is performed using a doctor blade method or the like. The first ceramic powder is different in composition or microstructure from the second ceramic powder. As the first ceramic powder, for example, zirconium oxide, yttrium oxide, magnesium oxide, nickel oxide, iron oxide, copper oxide, or a composite oxide containing one or more of these is preferable. The median diameter of this powder is, for example, not less than 0.2 μm and not more than 10 μm. Examples of the dispersion medium include hydrocarbons (toluene, xylene, solvent naphtha, etc.), ethers (ethylene glycol monoethyl ether, butyl carbitol, butyl carbitol acetate, etc.), alcohols (isopropanol, 1-butanol, ethanol, 2 -Ethylhexanol, terpineol, ethylene glycol, glycerin, etc.), ketones (acetone, methyl ethyl ketone, etc.), esters (butyl acetate, dimethyl glutarate, triacetin, etc.), polybasic acids (glutaric acid, etc.) can be used. In particular, it is preferable to use a “solvent having two or more ester bonds” such as a polybasic acid ester (for example, dimethyl glutarate) or an acid ester of a polyhydric alcohol (for example, triacetin).

  As the binder, a material having a glass transition point of 20 ° C. or higher and 48 ° C. or lower is used. Specifically, acrylic resin is mentioned, for example. Among these, it is particularly preferable to use poly (n-butyl methacrylate) (glass transition point: 20 ° C.). This is because the glass transition point is close to room temperature, and it is easy to maintain both the shape retention and adhesion of the green sheet. The volume ratio of the “substance having a glass transition point of 20 ° C. or higher and 48 ° C. or lower” in the binder is 30% or higher. The weight average molecular weight of the binder is preferably 8000 or more and 1,000,000 or less.

  The green sheet 20g (more specifically, slurry) may contain a plasticizer, a thickener, and a dispersion aid as necessary. Furthermore, the green sheet 20g (slurry) may contain a pore former (a material that disappears upon firing, for example, acrylic resin particles) in order to adjust the porosity after firing. As a result, among the portions that are not pores in the state of the green sheet 20g, the portion occupied by the pore former becomes pores in the fired film 20. In this case, large pores (for example, a diameter of 2 μm or more and 10 μm or less) can be formed inside the film 20. The porosity of the fired film 20 obtained by firing the green sheet 20g can also be achieved by adjusting the average particle size of the first ceramic powder contained in the green sheet 20g.

  The volume ratio of the binder to the entire green sheet 20g (hereinafter referred to as “binder volume ratio”) is 20% by volume to 60% by volume (in a dry state). Due to the glass transition point of the binder and the volume ratio of the binder being adjusted within the above range, this green sheet 20g (green sheet according to the embodiment of the present invention) has adhesiveness at room temperature. Have. This tackiness is mainly brought about by the binder contained in the green sheet. In addition, the green sheet 20g satisfies all the requirements described in the “Summary of Invention” section as “Green sheet having adhesiveness at room temperature”. This point will be described in detail later.

  Subsequently, the sheet 20g with PET film (the green sheet 20g) is attached to the upper surface (adhesive surface) of the substrate 10 as shown in FIG. It is done. At this time, the green sheet 20g is bonded and fixed to the upper surface of the substrate 10 by utilizing the adhesiveness of the green sheet 20g. Thereby, the laminated body shown in FIG. 6 is obtained. In addition, in the state shown in FIG. 6, it is preferable that the green sheet 20g has an adhesive force (JIS Z0237) of 0.001 kgf / mm or more.

The pressing force of the PET film-attached sheet 20g against the substrate 10 may be applied only by the own weight of the PET film-attached sheet 20g, or may be adjusted by pressing the upper surface of the PET film-attached sheet 20g through rubber or the like. Good. The pressing force of the sheet with PET film 20g against the substrate 10 is preferably 20 kgf / cm ² or less. Thereby, a deformation | transformation of the laminated body shown in FIG. 6 may be suppressed.

  Such a pressing state is continued at room temperature, for example, for 10 seconds to 300 seconds. In addition, after completion | finish of this press state, in order to adhere | attach the green sheet 20g with respect to the board | substrate 10 more reliably, it is 50 degreeC or more and 150 degrees C or less for 5 minutes or more and 60 minutes or less about the laminated body shown in FIG. A treatment (heat treatment) may be applied.

  Then, as shown in FIG. 7, the PET film is peeled off from the laminate shown in FIG. As a result, as shown in FIG. 8, a “green laminated body in which a relatively thick green sheet 20 g is bonded and laminated on the upper surface of the substrate 10 that is a dense fired body” is obtained.

  And this green laminated body is degreased at 400 degreeC or more and 750 degrees C or less over 1 hour or more and 10 hours or less. Thereafter, the degreased green laminate is fired at 900 ° C. to 1600 ° C. for 1 hour to 10 hours. As a result, the dispersion medium and the binder remaining in the green sheet 20g are volatilized and removed, and the fired laminated body shown in FIGS. 1 and 2, that is, “on the upper surface of the substrate 10 which is a dense fired body. A fired laminated body in which a porous fired film 20 is laminated ”is obtained.

(Appropriate range of glass transition point and volume ratio of binder contained in green sheet having adhesiveness at room temperature)
The above-mentioned “green sheet 20 g having adhesiveness at room temperature” has “a human being easy to handle by hand (so-called“ handling property ”is good)” and “sufficient adhesion to the substrate 10 at room temperature. And “make sure that it is securely fired during subsequent firing”.

  As a result of repeating various studies and experiments, the present inventor has found that these requirements are closely related to the “glass transition point and volume ratio” of the binder contained in the green sheet. In addition, the present inventor has found a range of “binder glass transition point” and “binder volume ratio” necessary to satisfy these requirements. Hereinafter, the test A performed to obtain this conclusion will be described.

(Test A)
In the test A, as shown in Table 1, with respect to the fired laminate according to the present embodiment shown in FIGS. 1 to 8, the “glass transition point of the binder contained in the green sheet (more specifically, slurry) and A plurality of samples having different “volume ratio combinations” were produced.

  As each sample (firing laminate), as shown in FIG. 1 and FIG. 2, a “firing laminate in which a plate-like porous fired film is laminated on the upper surface of a cuboid substrate that is a dense fired body” Was made. The width A (y-axis direction), depth B (x-axis direction), and height C (z-axis direction) of each sample (laminated fired body) were 50 mm, 100 mm, and 5 mm, respectively. The porosity of the substrate was 5% by volume or more and 10% by volume or less. The porosity of the fired film was 30% by volume or more and 60% by volume or less. As shown in FIGS. 3 to 8 described above, each sample is “green laminate obtained by adhering and laminating an adhesive green sheet on the upper surface of a substrate that is a dense fired body at room temperature. It was obtained by firing the “body”. Alumina was used as the second ceramic constituting the substrate. The green sheet was formed using a doctor blade method. The slurry for green sheets includes “Zirconia powder” as the first ceramic powder, “butanol and toluene” as the dispersion medium, “phthalate ester” as the plasticizer, and “acrylic resin beads” as the pore former. , Was included. The thickness of the green sheet was 100 μm.

  As binders having glass transition points of 5 ° C., 20 ° C., 26 ° C., 36 ° C., 48 ° C. and 65 ° C. contained in the slurry for green sheets, KC500 manufactured by Kyoeisha Chemical Co., Ltd. and acrylic binders M6003 and M6701 manufactured by Negami Kogyo respectively. M6664, M0603, M5001 were used. Firing of the green laminate (more specifically, firing of the green sheet) was performed at 1000 ° C. for 1 hour after degreasing at 600 ° C. for 2 hours. The volume ratio of the binder in Table 1 is a value in a dry state (a state in which the green sheet (slurry) is dried, that is, a state in which the binder in the slurry remains while the dispersion medium in the slurry is volatilized and removed). . The weight average molecular weight of the binder was 8000 to 1,000,000.

  In this test A, for each sample, when a green sheet was pasted onto a substrate that was a dense fired body, “whether the green sheet is easy to handle by hand” (viewpoint 1) and “green sheet for the substrate” (Aspect 2) is evaluated whether or not the adhesive strength is sufficiently provided at room temperature, and after the firing of the green laminate, “whether the green sheet is securely baked firmly” (Aspect 3) is evaluated. It was.

  These results are shown in Table 1. In Table 1, “◯” indicates that all the results of the respective evaluations are good, and “X” indicates that at least one of the results of the respective evaluations is bad. In Table 1, among the regions indicated by “x”, in the region surrounded by the thick line frame a, the green sheet is too soft and the shape of the green sheet cannot be maintained after peeling from the Lumirror. Evaluation on (Viewpoint 1) was bad. This is considered due to the fact that the glass transition point of the binder is too low with respect to room temperature. In the area surrounded by the thick line b, the evaluation of (Viewpoint 2) was bad due to the adhesiveness of the green sheet at room temperature being too low. This is considered due to the fact that the glass transition point of the binder is too high with respect to room temperature. In the region surrounded by the thick line c, the evaluation of (Viewpoint 2) was bad due to the adhesiveness of the green sheet at room temperature being too low. This is considered due to the fact that the volume ratio of the binder in the slurry is too low. In the region surrounded by the thick line d, the evaluation of (Viewpoint 3) was bad because the green sheet was insufficiently baked after firing. This is considered due to the fact that the volume ratio of the binder in the slurry is too high (that is, the volume ratio of the first ceramic powder is too low).

  From Table 1, when the glass transition point of the binder is 20 ° C. or more and 48 ° C. or less and the volume ratio of the binder is 20% by volume or more and 60% by volume or less, the above (viewpoint 1), (viewpoint 2), and It can be seen that the evaluation is good for all (viewpoint 3). As described above, it has been found that by satisfying these conditions, the green sheet satisfies all the above-described requirements as “a green sheet having adhesiveness at room temperature”.

(Suppression of cracks in green sheets affixed to the curved surface of the substrate)
In the embodiment described with reference to FIGS. 1 to 8 described above, the green sheet is attached on the plane of the substrate. On the other hand, consider a case where a green sheet is pasted on the curved surface of the substrate. In general, when a green sheet is affixed on a curved surface of a substrate as compared with the case where a green sheet is affixed on a plane of a substrate, the “green” is caused after firing due to internal stress generated in the green sheet. Cracks and peeling (hereinafter referred to as “cracks etc.”) are likely to occur in the “fired film that was a sheet”. The larger the thickness of the green sheet (fired film) with respect to the radius of curvature of the curved surface of the substrate, the more easily the cracks and the like are generated.

  In this regard, the present inventor stated above that “the glass transition point of the binder is 20 ° C. or more and 48 ° C. or less, and the volume ratio of the binder is 20% by volume or more and 60% by volume or less. It was found that when the “green sheet having” is used, the cracks and the like hardly occur even when the green sheet (fired film) is relatively thick with respect to the curvature radius of the curved surface of the substrate. Hereinafter, test B performed to obtain this conclusion will be described.

(Test B)
In test B, as shown in FIGS. 9 and 10 corresponding to FIGS. 1 and 2, respectively, a pair of side end surfaces is a densely fired body having convex convex surfaces, and a pair of substrates 10 A plurality of samples (fired laminates) including a pair of porous fired films 20 and 20 laminated on the surface including the side end faces were produced. As shown in FIGS. 11 and 12, these samples are fired “a green laminate obtained by attaching a pair of green sheets 20 g on a pair of side end surfaces of the substrate 10, which is a dense fired body”. Was obtained.

  As shown in FIG. 12, the radius of curvature of the side end face of the substrate 10 is R μm, and the thickness of the green sheet 20 g is t μm. The glass transition point of the binder is Tg (K (Kelvin)). In this test B, a plurality of samples for this embodiment with different combinations of (R / Tg) and t and a plurality of samples for comparative examples with different combinations of (R / Tg) and t were produced. . In the sample according to the present embodiment, the green sheet 20g is “adhesive at room temperature, where the glass transition point of the binder is 20 ° C. or higher and 48 ° C. or lower, and the volume ratio of the binder is 20% by volume or higher and 60% by volume or lower. A green sheet having properties was used. In the sample for the comparative example, “green sheet having a binder glass transition point of 80 ° C. or higher and a binder volume ratio of 20 volume% or more and 60 volume% or less” was used as the green sheet 20 g. In each sample, the materials of components other than the binder in the green sheet, the material and dimensions of the substrate, and various other test conditions including the firing conditions were the same as those in Test A.

  In this test B, for each sample, the green laminate shown in FIG. 11 and FIG. 12 was fired to obtain the fired laminate shown in FIG. 9 and FIG. It was evaluated whether or not cracks occurred. This evaluation was performed visually and using an optical microscope. FIG. 13 shows the evaluation results for a plurality of samples for the comparative example, and FIG. 14 shows the evaluation results for the plurality of samples for this embodiment. In FIG. 13 and FIG. 14, “◯” indicates that the crack or the like is not confirmed (no crack or the like), and “X” indicates that the crack or the like is confirmed (there is a crack or the like).

  As can be understood from FIG. 13, in the comparative example, no crack or the like occurs in the lower region of the straight line represented by “t = 2.9 · (R / Tg)” on the graph of FIG. It can be said that cracks and the like occur in the upper region of the straight line. Similarly, as can be understood from FIG. 14, in this embodiment, cracks or the like do not occur in the lower region of the straight line represented by “t = 255 · (R / Tg)” on the graph of FIG. 14. It can be said that cracks and the like occur in the upper region of the straight line.

  As is clear from comparison with FIGS. 13 and 14, it can be said that the area indicated by the fine dots in FIG. 15 is an area where cracks or the like are generated in the comparative example but no cracks or the like are generated in the present embodiment. . In other words, it is a “region where cracks and the like do not occur” which is not obtained in the comparative example and is obtained for the first time by adopting the present embodiment.

  From the above, the green of this embodiment having adhesiveness at room temperature, in which the glass transition point of the binder is 20 ° C. or higher and 48 ° C. or lower, and the volume ratio of the binder is 20% by volume or more and 60% by volume or less. The use of “sheet” means that the cracks and the like are less likely to occur even when the green sheet (fired film) is relatively thick with respect to the radius of curvature of the curved surface of the substrate as compared to the case of using the green sheet of the comparative example. Can do.

  The present invention is not limited to the above-described embodiments and modifications, and various modifications can be adopted within the scope of the present invention. For example, in each of the above embodiments, a substrate that is a dense fired body made of the second ceramic is used, but a substrate made of a dense metal may be used. A porous substrate made of the second ceramic or metal may be used.

  In each of the above embodiments, the “green laminate obtained by pasting a green sheet on a substrate that is a fired body” is fired to obtain a fired laminate. The green laminate obtained by attaching a green sheet on a certain substrate may be fired to obtain a fired laminate.

  Further, in each of the above embodiments, the fired film 20 obtained by firing the green sheet is porous (porosity is 30% by volume or more and 60% by volume or less), but the fired film 20 is dense (porosity is low). 10 volume% or less).

  Further, in each of the above embodiments, “a green laminate obtained by sticking only an adhesive green sheet on a fired substrate” is fired to form a two-layer fired laminate. However, “It is obtained by sticking a green sheet having adhesiveness on a substrate that is a fired body, and sticking a green sheet having no adhesiveness on the green sheet having adhesiveness. The “green laminate” may be fired to form a fired laminate of three or more layers.

  10 ... substrate, 20 ... fired film, 20g ... green sheet

Claims (7)

A flat plate-like substrate having a side end face that is a convex curved surface;
A green sheet adhered and laminated on the side end surface of the substrate;
Including
The green sheet includes a first inorganic powder and a binder including a material having a glass transition point of 20 ° C. or higher and 48 ° C. or lower, and a volume ratio of the binder to the entire green sheet is 20 volumes. % Or more and 60% by volume or less, a green sheet having adhesiveness at room temperature,
When the thickness of the green sheet is t (μm), the radius of curvature of the side end face of the substrate is R (μm), and the glass transition point of the binder is Tg (Kelvin), 2.9 · (R / Tg) ≦ t ≦ 225 · (R / Tg)
The said binder is a green laminated body which is an acrylic binder whose weight average molecular weight is 8000 or more and 1 million or less. In the green laminated body of Claim 1,
The green laminated body whose thickness of the said green sheet is 100 micrometers or more and 1000 micrometers or less. A green laminate comprising a substrate and a green sheet bonded and laminated on the substrate,
As the substrate, using a flat plate-like substrate having a side end surface that is a convex curved surface,
Forming and solidifying a slurry containing a first inorganic powder, a dispersion medium, and an acrylic binder having a weight average molecular weight of 8000 to 1,000,000 , including a material having a glass transition point of 20 ° C to 48 ° C; The volume ratio occupied by the binder with respect to the whole green sheet is 20% by volume or more and 60% by volume or less, creating the green sheet having adhesiveness at room temperature,
The prepared green sheet having adhesiveness is adhered and laminated on the side end surface of the substrate at room temperature, whereby the thickness of the green sheet is t (μm), and the side end surface of the substrate is When the radius of curvature is R (μm) and the glass transition point of the binder is Tg (Kelvin), the green that satisfies the relationship of 2.9 · (R / Tg) ≦ t ≦ 225 · (R / Tg) A method for producing a green laminate, which obtains a laminate. In the manufacturing method of the green laminated body of Claim 3,
The manufacturing method of the green laminated body whose thickness of the said green sheet is 100 micrometers or more and 1000 micrometers or less. Using the manufacturing method according to claim 3 or 4 , the green sheet having adhesiveness is adhered and laminated at room temperature on the substrate which is a dense fired body containing the second inorganic powder. Create a laminate,
By firing the created green laminate, a fired laminate in which a porous fired body containing the first inorganic powder is laminated on a dense fired body containing the second inorganic powder is obtained. The manufacturing method of a baked laminated body. In the manufacturing method of the baking laminated body of Claim 5 ,
The porosity of the porous fired body containing the first inorganic powder is 30% by volume or more and 60% by volume or less,
The porosity of the dense fired body containing the second inorganic powder is 10% by volume or less.
A method for producing a fired laminate. In the manufacturing method of the baked laminated body of Claim 5 or Claim 6 ,
The first inorganic powder is a first ceramic powder,
The method for producing a fired laminate, wherein the second inorganic powder is a second ceramic powder having a composition or a microstructure different from that of the first ceramic powder.

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