Sheet member, method for manufacturing sheet member, and method for manufacturing ceramic substrate

Abstract

To provide a sheet member capable of manufacturing a good ceramic substrate, a method for manufacturing the sheet member, and a method for manufacturing the ceramic substrate.SOLUTION: A sheet member 1 according to the present invention is a sheet member 1 in which ceramic particles are dispersed in an acrylic resin, the weight-average molecular weight of the acrylic resin being 150,000 or more and 650,000 or less, the content of the ceramic particles being 5 mass% or more and 25 mass% or less with respect to the entire sheet member 1, and the average particle size of the ceramic particles being 1 μm or more and 80 μm or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a sheet member, a method for manufacturing a sheet member, and a method for manufacturing a ceramic substrate. [Background technology]

[0002] Ceramic substrates are used as one type of substrate on which electronic components are mounted. The manufacturing process for ceramic substrates includes a firing step in which ceramic green sheets are fired to form ceramic substrates. To improve the efficiency of ceramic substrate manufacturing, multiple ceramic green sheets are sometimes stacked and fired at the same time. However, there is a concern that the stacked ceramic substrates may fuse together during firing, and that cracks may occur in the ceramic substrates when the fused ceramic substrates are peeled apart, resulting in defects of the ceramic substrates.

[0003] Therefore, for example, in Patent Document 1 below, a sheet member containing ceramic particles is interposed between the stacked ceramic green sheets, and the firing step is carried out. According to this firing method, since the sheet member is interposed between the stacked ceramic green sheets, fusion between the ceramic substrates can be suppressed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-77564 Summary of the Invention [Problem to be solved by the invention]

[0005] However, if the ceramic particles are unevenly distributed in the sheet member, the shape of the aggregates of ceramic particles may be transferred to the ceramic green sheet during firing, which may cause irregularities or scratches on the produced ceramic substrate. For this reason, there is a demand for a sheet member that can make it possible to produce a good ceramic substrate.

[0006] Therefore, an object of the present invention is to provide a sheet member that enables production of a good ceramic substrate, a method for manufacturing the sheet member, and a method for manufacturing a ceramic substrate. [Means for solving the problem]

[0007] The present invention is a sheet member in which ceramic particles are dispersed in an acrylic resin, characterized in that the weight-average molecular weight of the acrylic resin is 150,000 or more and 650,000 or less, the content of the ceramic particles is 5% by mass or more and 25% by mass or less with respect to the entire sheet member, and the average particle size of the ceramic particles is 1 μm or more and 80 μm or less.

[0008] Generally, a sheet member having ceramic particles dispersed in an acrylic resin is produced by dispersing ceramic particles in an acrylic resin-containing liquid, coating the acrylic resin-containing liquid with the dispersed ceramic particles in a sheet, drying the coated acrylic resin-containing liquid, and molding the dried sheet. As a result of extensive research, the inventors have found that a sheet member under these conditions can be produced as described above while suppressing uneven distribution of ceramic particles. Therefore, by firing a ceramic green sheet with such a sheet member between the sheets, the occurrence of irregularities and scratches on the ceramic substrate can be suppressed, making it possible to produce a good ceramic substrate.

[0009] The glass transition temperature of the acrylic resin is preferably 15°C or higher and 50°C or lower.

[0010] When the glass transition temperature of the acrylic resin is within the above temperature range, the formability of the sheet member is excellent compared to when the glass transition temperature of the acrylic resin is outside the above temperature range.

[0011] The ceramic particles are preferably spherical.

[0012] When the ceramic particles are spherical, they have better filling properties and flowability when made into a slurry than, for example, ceramic particles in the form of flakes, and therefore can be used to make a sheet member with better dispersibility.

[0013] It is also preferable that carbon particles are further dispersed in the acrylic resin.

[0014] Dispersion of carbon particles can reduce dimensional variations among a plurality of ceramic substrates obtained after firing.

[0015] The present invention also provides a method for producing a sheet member, comprising: a dispersing step of dispersing ceramic particles in an acrylic resin-containing liquid that is an acrylic resin emulsion or an acrylic resin solution; a coating step of coating the acrylic resin-containing liquid in which the ceramic particles have been dispersed into a sheet; a drying step of drying the coated acrylic resin-containing liquid; and a molding step of molding the sheet obtained by drying into the sheet member, wherein the weight-average molecular weight of the acrylic resin after the molding step is 150,000 or more and 650,000 or less, the content of the ceramic particles is 5% by mass or more and 25% by mass or less with respect to the entire sheet member, and the average particle size of the ceramic particles is 1 μm or more and 80 μm or less.

[0016] As a result of intensive research by the present inventors, it was found that by satisfying the above-mentioned conditions of the weight-average molecular weight of the acrylic resin, the content of the ceramic particles, and the average particle size, uneven distribution of the ceramic particles dispersed in the acrylic resin can be suppressed. Therefore, by firing a ceramic green sheet with a sheet member manufactured by this manufacturing method interposed therebetween, the occurrence of irregularities and scratches on the ceramic substrate can be suppressed, and it may be possible to manufacture a good ceramic substrate.

[0017] The acrylic resin-containing liquid is preferably an acrylic resin emulsion. The acrylic resin emulsion in the present invention is an acrylic resin-containing liquid in which water is a continuous phase and the acrylic resin is present as a dispersed phase. That is, it is an acrylic resin-containing liquid in which the acrylic resin is dispersed in water.

[0018] When an acrylic resin emulsion is used, no organic solvent is used, which reduces the environmental impact. Furthermore, when an acrylic resin emulsion is used, the sheet member produced tends to have better storage stability over time than when an aqueous acrylic resin solution is used. Therefore, by using an acrylic resin emulsion, it is possible to produce a sheet member with excellent storage stability over time while minimizing the burden on the environment.

[0019] The present invention also provides a method for manufacturing a ceramic substrate, comprising: a laminate formation step of placing sheet members, in which ceramic particles are dispersed in an acrylic resin, between the laminated ceramic green sheets to form a ceramic green sheet laminate; a firing step of firing the ceramic green sheet laminate to form a ceramic substrate laminate; and a peeling step of peeling the ceramic substrates from the ceramic substrate laminate, wherein the weight-average molecular weight of the acrylic resin in the sheet members is 150,000 or more and 650,000 or less, the content of the ceramic particles is 5% by mass or more and 25% by mass or less with respect to the entire sheet members, and the average particle size of the ceramic particles is 1 μm or more and 80 μm or less.

[0020] As described above, such a sheet member can suppress uneven distribution of ceramic particles, and therefore, by firing a ceramic green sheet laminate in which the sheet member is interposed between ceramic green sheets, a ceramic substrate in which the occurrence of unevenness and scratches is suppressed can be manufactured. [Effects of the Invention]

[0021] As described above, according to the present invention, there are provided a sheet member, a method for manufacturing a sheet member, and a method for manufacturing a ceramic substrate, which are capable of manufacturing a good ceramic substrate. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. [Figure 2] 10 is a flowchart showing the steps of a method for manufacturing a sheet member. [Figure 3] 3 is a flowchart showing the steps of a method for manufacturing a ceramic substrate. [Figure 4] FIG. 2 is a diagram showing the appearance of a ceramic green sheet laminate. [Figure 5] FIG. 2 is a diagram showing the appearance of a ceramic substrate laminate. [Figure 6] FIG. 10 is a diagram showing a peeling step. DETAILED DESCRIPTION OF THE INVENTION

[0023] Below, embodiments for carrying out the sheet member, the method for manufacturing the sheet member, and the method for manufacturing a ceramic substrate according to the present invention are illustrated with the accompanying drawings. The embodiments illustrated below are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The present invention can be modified and improved from the following embodiments without departing from the spirit thereof within the scope of the claims. Note that in the drawings referred to below, the dimensions of each component may be changed to facilitate understanding.

[0024] The sheet member of this embodiment is used by being placed between ceramic green sheets to be laminated when manufacturing a ceramic substrate by laminating and firing the ceramic green sheets. Therefore, before describing the sheet member of this embodiment, the ceramic green sheets will be described.

[0025] A ceramic green sheet is a green sheet that becomes a sintered ceramic body when fired. Such a ceramic green sheet can be produced, for example, as follows: First, a slurry is prepared by mixing predetermined amounts of ceramic powder, sintering aid, binder resin, solvent, plasticizer, etc. Next, the prepared slurry is formed into a flat sheet by, for example, a doctor blade method or a calendar roll method to produce a single-layer ceramic green sheet. Alternatively, a ceramic green sheet can be produced by filling a raw material powder into a molding machine and press-molding it.

[0026] Examples of ceramic particles used in the ceramic green sheets include aluminum oxide, aluminum nitride, silicon nitride, and compounds of aluminum oxide and silicon dioxide. Examples of binder resins include acrylic resins and polyvinyl butyral (PVB) resins. The content of the binder resin may be, for example, 20% to 70% by mass of the entire ceramic green sheets.

[0027] Next, the sheet member of this embodiment will be described.

[0028] Fig. 1 is a perspective view showing a sheet member 1. As shown in Fig. 1, the sheet member 1 has a rectangular, thin, sheet-like outer shape and includes main surfaces 10 and 11. In this embodiment, for example, the length of one side is approximately 80 mm, and the length of the side perpendicular to the one side is approximately 70 mm.

[0029] The thickness of the sheet member 1 is preferably at least 50 μm larger than the average particle size (D50) of ceramic particles described below. By setting the thickness of the sheet member 1 to the above size, it is possible to more effectively suppress the occurrence of irregularities and scratches in a ceramic substrate obtained by firing a ceramic green sheet laminate in which the sheet member 1 is interposed between ceramic green sheets.

[0030] The sheet member 1 contains an acrylic resin and ceramic particles dispersed in the acrylic resin.

[0031] Examples of ceramic particles include aluminum oxide, aluminum nitride, silicon dioxide, silicon nitride, and compounds thereof. The average particle size of the ceramic particles is 1 μm or more and 80 μm or less, preferably 10 μm or more and 50 μm or less, and more preferably 18 μm or more and 30 μm or less.

[0032] When the average particle size of the ceramic particles contained in the sheet member 1 is 1 μm or more and 80 μm or less, the acrylic resin can easily penetrate between the ceramic particles, and aggregation of the ceramic particles can be suppressed, resulting in a good dispersion state. Furthermore, because the ceramic particles have an appropriate size, settling of the ceramic particles can be suppressed in the coating step P13 described below, and the sheet member 1 can be produced while maintaining good dispersibility.

[0033] The average particle size of the ceramic particles is the median diameter (D50) measured by a laser diffraction scattering method using a 0.2 mass % sodium hexametaphosphate aqueous solution as a dispersion medium with an MT3300 manufactured by Microtrackbell.

[0034] The shape of the ceramic particles is not particularly limited, but is preferably spherical. When the ceramic particles are spherical, the ceramic particles have better packing properties and flowability when made into a slurry than when the ceramic particles have a shape other than spherical, and therefore a sheet member 1 with better dispersibility can be obtained.

[0035] The content of ceramic particles in the sheet member 1 is 5% by mass or more and 25% by mass or less, preferably 7% by mass or more and 20% by mass or less, and more preferably 9% by mass or more and 15% by mass or less, when the entire sheet member 1 is taken as 100% by mass.

[0036] When the content of ceramic particles in the sheet member 1 is 5% by mass or more and 25% by mass or less, the ceramic particles are present in an appropriate amount, which allows the acrylic resin to easily penetrate between the ceramic particles and prevents the ceramic particles from agglomerating, resulting in a good dispersion state. Furthermore, the presence of the ceramic particles in an appropriate amount can prevent excessive destruction of the ceramic particles by a ball mill or the like in the dispersion step P12 described below. This can prevent an increase in the surface area of ​​the ceramic particles, making them less likely to agglomerate.

[0037] Examples of acrylic resins include (meth)acrylic acid alkyl ester resin, (meth)acrylic acid alkyl ester styrene resin, and polyacrylate sodium resin. The content of the acrylic resin in the sheet member 1 is 20% by mass or more and 70% by mass or less, when the entire sheet member 1 is taken as 100% by mass. The weight-average molecular weight of the acrylic resin is 150,000 or more and 650,000 or less, preferably 250,000 or more and 550,000 or less, and more preferably 350,000 or more and 500,000 or less. When the entire sheet member 1 is taken as 100% by mass, the total content of the ceramic particles and the acrylic resin is 100% by mass or less.

[0038] When the weight-average molecular weight of the acrylic resin contained in the sheet member 1 is 150,000 or more and 650,000 or less, the movement of the polymer chains in the acrylic resin can be activated to an extent that the dispersed state of the ceramic particles can be maintained, and steric hindrance of the polymer chains can be effectively expressed, thereby suppressing aggregation of the ceramic particles in the sheet member 1 and improving dispersibility.

[0039] When the weight-average molecular weight of the acrylic resin contained in the sheet member 1 is 150,000 or more and 650,000 or less, the content of ceramic particles is 5% by mass or more and 25% by mass or less relative to the entire sheet member 1, and the average particle size of the ceramic particles is 1 μm or more and 80 μm or less, it is believed that the above effects can act in combination, and a sheet member 1 can be produced in which the ceramic particles are prevented from being unevenly distributed and dispersed in the acrylic resin.

[0040] The glass transition temperature of the acrylic resin is preferably 15°C or higher and 50°C or lower from the viewpoint of excellent moldability when producing the sheet member 1. Whether the moldability is good or not is evaluated based on whether powder is generated or not and whether cracks occur in the sheet member 1 when the sheet member 1 is molded.

[0041] The binder resin used in the ceramic green sheets and the acrylic resin used in the sheet member 1 are preferably different resins. "Different resins" includes not only resins of different series, but also resins of the same series that differ, for example, in the main chain composition or the type of functional group bonded to the main chain. Therefore, when the binder resin used in the ceramic green sheets is an acrylic resin, the acrylic resin used in the sheet member 1 and the acrylic resin used in the ceramic green sheets preferably differ from each other in the main chain composition or the type of functional group bonded to the main chain. Even when the resin used in the ceramic green sheets is an acrylic resin, the acrylic resin used in the ceramic green sheets and the acrylic resin used in the sheet member 1 may differ from each other in properties such as thermal decomposition temperature. Furthermore, the thermal decomposition temperature of the acrylic resin used in the sheet member 1 is preferably lower than that of the acrylic resin used in the ceramic green sheets.

[0042] Furthermore, the sheet member 1 may further contain carbon particles dispersed in the acrylic resin. Examples of the carbon particles include those having an average particle size of 20 μm to 30 μm. The particle size is a value measured in the same manner as the particle size of ceramic particles. When the sheet member 1 contains carbon particles, the content of the carbon particles in the sheet member 1 is 20% by mass or more and 60% by mass or less, when the entire sheet member 1 is taken as 100% by mass. When the sheet member 1 contains carbon particles, when the entire sheet member 1 is taken as 100% by mass, the total content of the ceramic particles, the acrylic resin, and the carbon particles is 100% by mass or less.

[0043] Furthermore, the sheet member 1 may contain other materials such as a dispersant, a thickener, and an antifoaming agent, as needed.

[0044] Next, a method for manufacturing the sheet member 1 will be described.

[0045] Fig. 2 is a flowchart showing the steps of a method for manufacturing the sheet member 1 of this embodiment. As shown in Fig. 2, the method for manufacturing the sheet member 1 of this embodiment includes a preparation step P11, a dispersion step P12, a coating step P13, a drying step P14, and a molding step P15.

[0046] (Preparation process P11) This step is a step of preparing an acrylic resin-containing liquid, ceramic particles, and, if necessary, carbon particles. In this embodiment, the acrylic resin-containing liquid may be an acrylic resin emulsion in which an acrylic resin is dispersed in water, an aqueous acrylic resin solution in which an acrylic resin is dissolved in water, or an organic acrylic resin solution in which an acrylic resin is dissolved in an organic solvent.

[0047] The acrylic resin-containing liquid may be commercially available or may be produced by a known method. For example, an acrylic resin emulsion may be produced by known emulsion polymerization, and an aqueous acrylic resin solution and an organic acrylic resin solution may be produced by known solution polymerization.

[0048] In the case of an acrylic resin emulsion, the acrylic resin is stably dispersed in water as emulsion particles, and the viscosity of the slurry obtained in the dispersion step P12 described below can be set lower than that of an aqueous acrylic resin solution or an organic acrylic resin solution. This improves the handleability of the slurry. Examples of acrylic resin emulsions include the Nikasol series manufactured by Nippon Carbide Industries Co., Ltd., Movinyl DM772 manufactured by Hoechst Chemical Co., Ltd., and Joncryl 352D and Joncryl 775 manufactured by BASF. Examples of aqueous acrylic resin solutions in which acrylic resin is dissolved in water include Aqualic DL-522 manufactured by Nippon Shokubai Co., Ltd. Examples of organic acrylic resin solutions in which acrylic resin is dissolved in an organic solvent include a solution of Mitsubishi Chemical Corporation's Metablen P-570A dissolved in toluene to give a solid content of 10% by weight, Fujikura Chemical Co., Ltd.'s Acrybase ALP-13 dissolved in toluene to give a solid content of 25% by weight, and Kyoeisha Chemical Co., Ltd.'s Oricox KC-7025T (solid content 25% by weight).

[0049] As ceramic particles, ceramic particles such as the above-mentioned aluminum oxide, aluminum nitride, silicon dioxide, silicon nitride, and compounds thereof are prepared, and, if necessary, the above-mentioned carbon particles are prepared.

[0050] (Dispersion process P12) This step involves dispersing ceramic particles, and optionally carbon particles, in the acrylic resin-containing liquid prepared in the preparation step P11. In this step, ceramic particles and optionally carbon particles are first added to the acrylic resin-containing liquid, and then the ceramic particles and other components are dispersed. A dispersant may also be added if necessary. Examples of dispersants include sorbitan sesquioleate, and the amount of dispersant added to the acrylic resin-containing liquid may be, for example, 0.4% to 1.6% by mass. For dispersion, a ball mill, a bead mill, an extruder, a roll mill, an ultrasonic or pressure homogenizer, or the like can be used. From the perspective of uniformly dispersing the ceramic particles in the acrylic resin-containing liquid, it is preferable to use a ball mill. In this way, a slurry in which the ceramic particles and other components are dispersed in the acrylic resin-containing liquid is obtained.

[0051] (Coating process P13) This step is a step of applying the acrylic resin-containing liquid in which ceramic particles and the like are dispersed in a sheet form. In this step, the slurry obtained in the dispersion step P12 is applied to a film-like substrate using, for example, a coater, to apply the sheet form. In this embodiment, in this step, the acrylic resin-containing liquid is applied in a long form onto a long substrate. In other words, the acrylic resin-containing liquid is applied in a longer form than the state shown in FIG. 1.

[0052] (Drying process P14) This process is a process of drying the acrylic resin-containing liquid that has been applied in a sheet form. When the acrylic resin-containing liquid is an acrylic resin emulsion or an aqueous acrylic resin solution, the acrylic resin-containing liquid is dried by evaporating water from the formed slurry. When the acrylic resin-containing liquid is an organic acrylic resin solution in which an acrylic resin is dissolved in an organic solvent, the acrylic resin-containing liquid is dried by evaporating the organic solvent. In this process, it is preferable to harden the acrylic resin-containing liquid at a temperature equal to or higher than the glass transition temperature of the acrylic resin, and then lower the temperature. In this way, the acrylic resin-containing liquid is formed into a sheet form.

[0053] (Molding process P15) This step is a step of forming the sheet obtained in the drying step P14 into the sheet member 1. Since the acrylic resin-containing liquid is applied in a long shape in the coating step P13, in this step, the sheet obtained after the drying step P14 is formed into a desired size. This forming is preferably performed by cutting. At this time, cutting is preferably performed using a mold.

[0054] In this way, the sheet member 1 in which ceramic particles and the like are dispersed in the acrylic resin is obtained.

[0055] Next, a description will be given of a method for manufacturing a ceramic substrate using the sheet member 1 of this embodiment. In this embodiment, a description will be given of a method for manufacturing a ceramic substrate containing aluminum oxide as ceramic particles.

[0056] Fig. 3 is a flowchart showing the steps of a method for manufacturing a ceramic substrate using the sheet member 1. As shown in Fig. 3, the method for manufacturing a ceramic substrate includes a preparation step P21, a laminate formation step P22, a firing step P23, and a peeling step P24.

[0057] (Preparation process P21) This step is a step of preparing a sheet member 1 and a ceramic green sheet. As the sheet member 1, it is preferable to use a sheet member 1 obtained by the above-mentioned manufacturing method, but it may also be a sheet member 1 obtained by a manufacturing method different from the above. Also, in this step, a ceramic green sheet is prepared. As the ceramic green sheet, it is preferable to use a ceramic green sheet obtained by the above-mentioned manufacturing method, but it may also be a ceramic green sheet obtained by a manufacturing method different from the above. The ceramic green sheet may be prepared so that the dimensions of the main surface are the same as those of the sheet member 1.

[0058] (Laminate formation process P22) This step is a step of forming a ceramic green sheet laminate by placing sheet members 1 between the ceramic green sheets to be stacked. FIG. 4 is a diagram showing the appearance of a ceramic green sheet laminate 3P. As shown in FIG. 4, in this step, ceramic green sheets 2P and sheet members 1 are alternately stacked such that the ceramic green sheets 2P prepared in preparation step P21 contact the main surfaces 10, 11 of the sheet members 1 prepared in preparation step P21. In this way, a ceramic green sheet laminate 3P is formed in which sheet members 1 are placed between the stacked ceramic green sheets 2P. Note that FIG. 4 shows an example in which the dimensions of the main surfaces 10, 11 of the sheet members 1 and the dimensions of the main surfaces of the ceramic green sheets 2P are approximately the same.

[0059] (Firing process P23) This step is a step of firing the ceramic green sheet laminate 3P to form a ceramic substrate laminate. As described above, when the ceramic substrate produced by this production method contains aluminum oxide, the ceramic green sheets 2P are fired at a predetermined temperature at which the aluminum oxide in the laminated ceramic green sheets 2P can be sintered. This predetermined temperature is, for example, 1400°C to 1600°C.

[0060] When the ceramic green sheet laminate 3P is fired, the acrylic resin in the sheet members 1 and the binder resin in the ceramic green sheets 2P soften. Over time, the binder resin, residual solvent, plasticizer, etc. in the ceramic green sheets 2P disappear, leaving only ceramic particles. These remaining ceramic particles are sintered, transforming the ceramic green sheets 2P into a ceramic substrate. The acrylic resin, carbon particles, dispersant, etc. in the sheet members 1 disappear, leaving only the ceramic particles. In this process, when the ceramic green sheets 2P are sintered into the ceramic substrate 2, the ceramic particles remaining from the sheet members 1 are positioned between the ceramic green sheets 2P. Therefore, the ceramic green sheets 2P are kept spaced apart during this process. As shown in FIG. 5, a ceramic substrate laminate 3 is thus formed, with the ceramic particles of the sheet members 1 interposed between the sintered ceramic substrates 2. Note that the ceramic particles remaining from the sheet members 1 are omitted from FIG. 5.

[0061] (Peeling process P24) This step is a step of peeling off the ceramic substrate 2 from the ceramic substrate laminate 3 formed in the firing step P23.

[0062] As described above, ceramic particles derived from the sheet members 1 are present between the ceramic substrates 2 of the ceramic substrate laminate 3. In this step, as shown in Fig. 6 , the ceramic substrates 2 can be easily peeled off from the ceramic substrate laminate 3, and cracking or damage to the ceramic substrates 2 when peeling them off from the ceramic substrate laminate 3 is suppressed.

[0063] In this manner, a plurality of ceramic substrates 2 can be manufactured through the preparation step P21, the laminate formation step P22, the firing step P23, and the peeling step P24.

[0064] It should be noted that the ceramic particles originating from the sheet member 1 and adhering to the surface of the peeled ceramic substrate 2 can be easily removed by various methods such as blasting and honing.

[0065] Next, the sheet member 1 will be described in more detail using examples and comparative examples.

[0066] Example 1 The sheet member 1 was produced according to the above-described method for producing the sheet member 1. An acrylic resin emulsion was used as the acrylic resin-containing liquid. The weight-average molecular weight of the acrylic resin contained in the acrylic resin emulsion was 400,000. The glass transition temperature of this acrylic resin was 30°C. The content of the acrylic resin in the acrylic resin emulsion was adjusted to be 60% by mass with respect to the entire sheet member 1 when it was formed. Aluminum oxide having an average particle size of 20 μm was used as the ceramic particles. The content of the ceramic particles was adjusted to be 10% by mass with respect to the entire sheet member 1 when it was formed. Carbon particles were also dispersed in the acrylic resin emulsion. The average particle size of the carbon particles was 25 μm, and the content of the carbon particles was adjusted to be 30% by mass with respect to the entire sheet member 1 when it was formed. The thickness of the sheet member 1 after drying was adjusted to be 70 μm.

[0067] (Examples 2 to 19, Comparative Examples 1 to 6) Sheet member 1 was produced in the same manner as in Example 1, except that the acrylic resin content, weight average molecular weight (Mw), glass transition temperature (Tg), ceramic particle content, particle size, and thickness of sheet member 1 were set as shown in Table 1. However, in Examples 16 and 17, an organic acrylic resin solution (solvent resin) in which acrylic resin is dissolved in an organic solvent and an aqueous acrylic resin solution (aqueous resin) in which acrylic resin is dissolved in water were used as the acrylic resin-containing liquid, respectively. In addition, in Examples 18 and 19, silicon dioxide and silicon nitride were used as the ceramic particles, respectively.

[0068] The conditions for Examples 1 to 19 and Comparative Examples 1 to 6 are shown in Table 1. TIFF2025145033000002.tif247170

[0069] The following items were evaluated:

[0070] (Agglomeration state of ceramic particles) The presence or absence of agglomeration of ceramic particles was observed under a microscope for the sheet member 1. The term "agglomeration" refers to a state in which three or more ceramic particles with a diameter equal to or greater than the average particle diameter (D50) are bonded together, and the maximum diameter of the group of bonded ceramic particles (particle group) is 80% or more of the thickness of the sheet member 1. A: No agglomeration of ceramic particles can be observed. B: Ceramic particle agglomeration was observed in one or two places. C: Ceramic particle agglomerations were observed in 3 to 4 places. D: Ceramic particle agglomerations were observed in five or more places. Although A to C can be used as the sheet member 1 for manufacturing the ceramic substrate 2, D has large uneven distribution of ceramic particles and is not acceptable as the sheet member 1 for manufacturing the ceramic substrate.

[0071] (Moldability of sheet member 1) In the molding step P15, the following state was observed. A: The sheet material does not crack and no ceramic powder is released. B: The sheet material does not crack, but ceramic particle powder is released. C: Cracks appear in part of the sheet material. D: The sheet member splits. A to C can be used as the sheet member 1 for manufacturing the ceramic substrate 2, but D is not acceptable as the sheet member 1 for manufacturing the ceramic substrate 2.

[0072] The evaluation results are shown in Table 2. TIFF2025145033000003.tif167170

[0073] The storage stability over time was also evaluated, although not shown in Table 2. The sheet members 1 produced in Examples 1 to 15, 18, and 19 using the acrylic resin emulsion did not develop cracks, but the sheet member 1 produced in Example 17 using the aqueous acrylic resin solution developed cracks.

[0074] As shown in Table 2, the sheet members 1 produced in Examples 1 to 19 resulted in suppressed uneven distribution of ceramic particles. That is, it was found that uneven distribution of ceramic particles was suppressed when the weight-average molecular weight of the acrylic resin in the sheet member 1 was 150,000 or more and 650,000 or less, the content of the ceramic particles in the entire sheet member 1 was 5% by mass or more and 25% by mass or less, and the average particle size of the ceramic particles was 1 μm or more and 80 μm or less. That is, it was found that uneven distribution of ceramic particles was suppressed when the sheet member 1 included a dispersion step P12, a coating step P13, a drying step P14, and a molding step P15, and the weight-average molecular weight of the acrylic resin was 150,000 or more and 650,000 or less, the content of the ceramic particles in the entire sheet member 1 was 5% by mass or more and 25% by mass or less, and the average particle size of the ceramic particles was 1 μm or more and 80 μm or less. Therefore, by inserting the sheet member 1 produced in Examples 1 to 19, a ceramic green sheet laminate 3P can be formed and fired to form a ceramic substrate laminate 3, and then the ceramic substrate 2 can be peeled off to produce a good ceramic substrate 2 with reduced unevenness and scratches.

[0075] Furthermore, when the glass transition temperature of the acrylic resin is 15°C or higher and 50°C or lower, the sheet member 1 has excellent formability. [Industrial Applicability]

[0076] According to the present invention, a sheet member, a method for manufacturing a sheet member, and a method for manufacturing a ceramic substrate are provided that enable the production of a good ceramic substrate, and can be used in the field of manufacturing ceramic substrates for mounting electronic components and other ceramic substrates. [Explanation of symbols]

[0077] 1. Sheet member 10, 11... Main surface 2P...Ceramic green sheet 2. Ceramic substrate 3P....Ceramic green sheet laminate 3. Ceramic substrate laminate

Claims

1. A sheet member in which ceramic particles are dispersed in an acrylic resin, The weight average molecular weight of the acrylic resin is 150,000 or more and 650,000 or less, The content of the ceramic particles is 5% by mass or more and 25% by mass or less with respect to the entire sheet member, The average particle size of the ceramic particles is 1 μm or more and 80 μm or less. A sheet member characterized by:

2. The glass transition temperature of the acrylic resin is 15°C or higher and 50°C or lower. The sheet member according to claim 1 .

3. The ceramic particles are spherical The sheet member according to claim 1 .

4. Carbon particles are further dispersed in the acrylic resin. The sheet member according to claim 1 .

5. A method for manufacturing a sheet member in which ceramic particles are dispersed in an acrylic resin, comprising: a dispersing step of dispersing ceramic particles in an acrylic resin-containing liquid, which is an acrylic resin emulsion or an acrylic resin solution; a coating step of coating the acrylic resin-containing liquid in which the ceramic particles are dispersed into a sheet; a drying step of drying the applied acrylic resin-containing liquid; a molding step of molding the sheet obtained by drying into the sheet member; Equipped with The weight average molecular weight of the acrylic resin after the drying step is 150,000 or more and 650,000 or less, The content of the ceramic particles is 5% by mass or more and 25% by mass or less with respect to the entire sheet member, The average particle size of the ceramic particles is 1 μm or more and 80 μm or less. A method for manufacturing a sheet member, comprising:

6. The acrylic resin-containing liquid is an acrylic resin emulsion. The method for manufacturing a sheet member according to claim 5 .

7. a laminate forming step of forming a ceramic green sheet laminate by disposing a sheet member having ceramic particles dispersed in an acrylic resin between the ceramic green sheets to be laminated; a firing step of firing the ceramic green sheet laminate to form a ceramic substrate laminate; a peeling step of peeling the ceramic substrate from the ceramic substrate laminate; Equipped with In the sheet member, the weight average molecular weight of the acrylic resin is 150,000 or more and 650,000 or less, the content of the ceramic particles is 5% by mass or more and 25% by mass or less with respect to the entire sheet member, and the average particle size of the ceramic particles is 1 μm or more and 80 μm or less. A method for manufacturing a ceramic substrate, comprising:

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