Method for manufacturing ceramic green sheet

Abstract

Provided is a method which is for manufacturing a ceramic green sheet using a ceramic green sheet-manufacturing release film having a substrate and a release agent layer, and by which the green sheet is easily released, the change in easy releasability over time is small, and excellent easy releasability can be stably achieved even after a long period of time has elapsed since green sheet coating. The problem is solved by a method for manufacturing a ceramic green sheet, the method comprising: a) a step for applying a ceramic slurry onto a ceramic green sheet-manufacturing release film; b) a step for forming a ceramic green sheet from the ceramic slurry applied in the a) step; and c) a step for releasing the ceramic green sheet formed in the b) step from the ceramic green sheet-manufacturing release film, wherein the ceramic green sheet-manufacturing release film has a substrate and a release agent layer provided on at least one side of the substrate, the Si amount Si0 on the surface on the reverse side of the release agent layer from the substrate before the a) step is at least 0.003 g / m2, and the difference between the Si amount Sic on the surface on the reverse side of the release agent layer from the substrate after the step c) and Si0, that is, δSi=Sic-Si0, is at least -0.00027 g / m2.

Description

Ceramic green sheet manufacturing method

[0001] The present invention relates to a method for producing a ceramic green sheet, and more specifically, to a method for producing a ceramic green sheet that allows easy peeling of the green sheet, exhibits little change in peelability over time, and can stably achieve excellent peelability even long periods after slurry coating during green sheet production, and is particularly suitable for use in producing various ceramic products such as multilayer ceramic capacitors and multilayer ceramic substrates.

[0002] In the manufacture of sheet-like ceramic members, a method for manufacturing a ceramic green sheet using a release film for manufacturing a ceramic green sheet has been conventionally adopted. For example, to manufacture multilayer ceramic products such as multilayer ceramic capacitors and multilayer ceramic substrates, a ceramic green sheet is formed on a release film for manufacturing a ceramic green sheet, and then multiple ceramic green sheets obtained are stacked and fired. In recent years, with the miniaturization and high performance of electronic devices, multilayer ceramic capacitors and multilayer ceramic substrates have become increasingly smaller and more multilayered. To achieve multi-layering, ceramic green sheets must be thin. From the viewpoint of preventing defects such as pinholes and uneven thickness in thin ceramic green sheets and effectively suppressing breakage when thin ceramic green sheets are peeled off from a release film, a release film for producing ceramic green sheets has been proposed, which has a substrate and a release agent layer of specific components, in which the arithmetic mean roughness (Ra) and maximum projection height (Rp) on the surface of the release agent layer opposite the substrate are each equal to or less than a predetermined value, and the arithmetic mean roughness (Ra) and maximum projection height (Rp) on the surface of the substrate opposite the release agent layer are each within a predetermined numerical range (see, for example, Patent Document 1).

[0003] In the production of various ceramic products such as multilayer ceramic capacitors and multilayer ceramic substrates, it is required that the ceramic green sheet formed on the release film for producing the ceramic green sheet be easily peeled from the viewpoints of the quality and productivity of the ceramic product. However, in conventional ceramic green sheet production methods, even if the ceramic green sheet is easily peeled immediately after being formed by coating the slurry, the peelability may decrease when the sheet is stored, for example, for about one week after coating. This may result in difficult peeling due to storage or the ceramic green sheet may break when peeled after storage, and improvements in this area have been desired.

[0004] International Publication No. 2013 / 145865 A1 Brochure

[0005] In view of the above technical background, an object of the present invention is to provide a method for producing a ceramic green sheet using a release film for producing a ceramic green sheet having a substrate and a release agent layer, which method allows the green sheet to be easily peeled, has little change in peelability over time, and can stably achieve excellent peelability even long periods of time after the green sheet is coated.

[0006] As a result of intensive research, the present inventors have found that in a method for producing a ceramic green sheet using a release film for producing a ceramic green sheet having a substrate and a release agent layer provided on at least one side of the substrate, by setting the Si amount on the surface of the release agent layer and the change in Si amount before and after ceramic slurry coating, green sheet formation, and peeling within predetermined numerical ranges, it is possible to stabilize easy peelability over time at a high level that exceeds the limits of conventional technology, and have completed the present invention. That is, the present invention is a method for producing a ceramic green sheet, comprising: [1] a) a step of coating a ceramic slurry on a release film for producing a ceramic green sheet, b) a step of forming a ceramic green sheet from the ceramic slurry coated in step a), and c) a step of peeling the ceramic green sheet formed in step b) from the release film for producing a ceramic green sheet, wherein the release film for producing a ceramic green sheet has a substrate and a release agent layer provided on at least one side of the substrate, and the Si amount on the surface of the release agent layer opposite to the substrate before step a) is Si ０ is 0.003 g / m ２ and after the step c), the amount of Si in the release agent layer on the surface opposite to the substrate is ｃ and the above Si ０ The difference between δSi and Si ｃ -Si ０ is -0.00027 g / m ２ The present invention relates to the method for producing the ceramic green sheet.

[0007] [2] to [6] below are all preferred aspects or embodiments of the present invention. [2] The method for producing a ceramic green sheet according to [1], wherein the ceramic slurry contains polyvinyl butyral having a hydroxyl value of 20 mol% or more. [3] The method for producing a ceramic green sheet according to [1] or [2], which includes a step of printing internal electrodes on the ceramic green sheet between steps b) and c). [4] The method for producing a ceramic product, which includes a step of producing a ceramic green sheet by the method for producing a ceramic green sheet according to any one of [1] to [3]. [5] The method for producing a ceramic product according to [4], which further includes a step of firing the ceramic green sheet. [6] The method for producing a ceramic product according to [4] or [5], wherein the ceramic product is a multilayer ceramic capacitor or a multilayer ceramic substrate.

[0008] Furthermore, the following [1'] to [6'] are all examples of release films for producing ceramic green sheets that are preferably used in the production method of the present invention. [1'] A release film for producing ceramic green sheets having a substrate and a release agent layer provided on at least one side of the substrate, wherein the Si amount of the release agent layer on the side opposite to the substrate is 1.5 to 1.0%. １ is 0.003 g / m ２ The ceramic slurry having the following composition was applied to the surface of the release agent layer opposite to the substrate, dried, and then stored in a constant temperature and humidity environment of 23±2°C x 50±5% RH for one week, and the amount of Si after peeling was determined. ２ and the above Si １ The difference between δSi and Si ２ -Si １ is -0.00027 g / m ２The release film for producing a ceramic green sheet, as described above: A ceramic slurry containing A) 45% by mass of barium titanate particles, B) 3.6% by mass of polyvinyl butyral, C) 0.9% by mass of dibutyl phthalate, D) 25% by mass of toluene, and E) 25% by mass of ethanol. [2'] The release film for producing a ceramic green sheet, as described in [1'], wherein the ceramic slurry has a coating thickness of 50 μm before drying, the drying conditions are 70°C and 2 minutes, and the peeling is performed at an angle of 180°. [3'] The release film for producing a ceramic green sheet, as described in [1'] or [2'], wherein the release agent layer contains a cured product of a curable composition, the curable composition contains at least one reactive compound (a) having at least one reactive functional group selected from the group consisting of a (meth)acryloyl group, a hydroxyl group, and an epoxy group, and the total amount of the reactive compound (a) accounts for 50% or more of the release agent layer by mass. [4'] The release film for producing a ceramic green sheet according to [3'], wherein the curable composition contains, as the reactive compound (a), at least one reactive silicone (a1) having at least one reactive functional group selected from the group consisting of a (meth)acryloyl group, a hydroxyl group, and an epoxy group, and a siloxane skeleton, and at least one reactive compound (a2) having the same reactive functional group as the reactive silicone (a1) and having a reactive functional group equivalent of 2000 g / mol or less. [5'] The release film for producing a ceramic green sheet according to [4'], wherein the curable composition further contains a film-forming compound (a3) ​​having two or more (meth)acryloyl groups per molecule. [6'] The release film for producing a ceramic green sheet according to any one of [1'] to [5'], wherein the arithmetic mean roughness (Ra) of the surface of the base material facing the release agent layer is 1 to 70 nm.

[0009] The method for producing a ceramic green sheet of the present invention realizes technical effects of great practical value at a high level that surpasses the limitations of conventional techniques, such as easy peeling of a ceramic green sheet formed on a release film for producing a ceramic green sheet, little change in peelability over time, and stable excellent peelability even long periods after the green sheet is applied, and can be suitably used in the production of various ceramic products. For example, the method can significantly improve the productivity of various ceramic products such as multilayer ceramic capacitors and multilayer ceramic substrates, and can be particularly suitably used in the production of these products.

[0010] FIG. 1 is a schematic view showing an example of a release film for producing a ceramic green sheet used in the production method of the present invention.

[0011] The present invention provides a method for producing a ceramic green sheet, comprising: a) a step of applying a ceramic slurry onto a release film for producing a ceramic green sheet; b) a step of forming a ceramic green sheet from the ceramic slurry applied in the step a); and c) a step of peeling the ceramic green sheet formed in the step b) from the release film for producing a ceramic green sheet, wherein the release film for producing a ceramic green sheet has a substrate and a release agent layer provided on at least one side of the substrate, and the Si amount of the release agent layer on the surface opposite to the substrate before the step a) is 100% or less. ０ is 0.003 g / m ２ and after the step c), the amount of Si in the release agent layer on the surface opposite to the substrate is ｃ and the above Si ０ The difference between δSi and Si ｃ -Si ０ is -0.00027 g / m ２ This completes the method for producing the ceramic green sheet.

[0012] That is, the method for producing a ceramic green sheet of the present invention comprises the steps of: a) applying a ceramic slurry to a release film for producing a ceramic green sheet; b) forming a ceramic green sheet from the ceramic slurry applied in step a); and c) peeling the ceramic green sheet formed in step b) from the release film for producing a ceramic green sheet, wherein the Si content of the release agent layer on the surface opposite to the substrate of the release film for producing a ceramic green sheet satisfies the following conditions i) and ii): i) The Si content (initial Si content) of the surface opposite to the substrate of the release agent layer before step a) Si ０ is 0.003 g / m ２ ii) The amount of Si on the surface of the release agent layer opposite to the substrate after step c) (amount of Si after peeling) ｃ and the above Si ０ The difference between δSi and Si ｃ -Si ０ is -0.00027 g / m ２ That's all.

[0013] Initial Si amount Si ０ When the Si content change δSi is within the above-mentioned ranges, in combination with other technical features of the present invention, the production method of the present invention using the release film for producing ceramic green sheets described above makes it easy to peel off the ceramic green sheets formed thereon, and there is little change in the peelability over time, so that excellent peelability can be stably achieved even long periods after the green sheet is coated, thereby achieving technical effects of great practical value at a high level that exceeds the limits of conventional technology. ０ The mechanism by which excellent peelability of the ceramic green sheet and suppression of deterioration over time can be achieved by ensuring that Si and δSi are within the above-mentioned ranges is not entirely clear. ０ is 0.003 g / m ２ By setting the δSi at -0.00027 g / m or more, the release force of the release film can be stably exhibited, and the δSi is -0.00027 g / m ２From the above, it is presumed that even if a long period of time has passed since the green sheet was applied, the amount of Si present on the surface of the release film after peeling remains almost unchanged from the initial amount and is stable over time.

[0014] The amount of Si on the surface of the release agent layer opposite to the substrate of the release film for producing a ceramic green sheet used in the production method of the present invention is Si ０ and Si ｃ can be measured by a method conventionally known in the art, for example, by fluorescent X-ray analysis. More specifically, it can be measured by the method described in the examples of the present specification. The change in Si content δSi is calculated by the above-measured Si content δSi. ０ and Si ｃ From the formula δSi=Si ｃ -Si ０ It can be calculated according to:

[0015] The initial Si amount Si on the surface of the release agent layer opposite to the substrate of the release film for producing a ceramic green sheet used in the production method of the present invention ０ is 0.005 to 0.200 g / m ２ and preferably from 0.010 to 0.150 g / m ２ More preferably, it is 0.015 to 0.100 g / m ２ It is particularly preferable that the change δSi in the Si content on the surface of the release agent layer opposite to the substrate in the release film for producing a ceramic green sheet used in the production method of the present invention is −0.00026 to 0.0025 g / m ２ and preferably from −0.00025 to 0.0020 g / m ２ More preferably, it is -0.00024 to 0.0017 g / m ２ It is particularly preferred that:

[0016] The initial Si amount Si on the surface of the release agent layer opposite to the substrate ０ The amount of Si after step c) in the manufacturing method of the present invention having the above steps a) to c) is Si ｃand the change in Si content δSi can be appropriately adjusted by adjusting the type and amount of material constituting the release agent layer, the coating amount of the release agent layer, curing conditions such as the drying temperature and the amount of active energy ray irradiation, etc. In particular, they can be appropriately adjusted by adjusting the reactive functional group equivalent and amount used of a reactive compound (a) having at least one reactive functional group selected from the group consisting of a (meth)acryloyl group, a hydroxyl group, and an epoxy group, particularly a reactive compound (a2) having the same reactive functional group as the reactive silicone (a1) and having a reactive functional group equivalent of 2000 g / mol or less, or a film-forming compound (a3) ​​having two or more (meth)acryloyl groups in one molecule.

[0017] As described above, the release film for producing a ceramic green sheet used in the production method of the present invention has a substrate and a release agent layer. The release film for producing a ceramic green sheet used in the production method of the present invention only needs to have a substrate and a release agent layer, and may or may not have other layers. Therefore, as shown in FIG. 1, the release film for producing a ceramic green sheet used in the production method of the present invention may consist of only a substrate (13) and a release agent layer (12), or may have other layers such as an antistatic layer in addition to the substrate and release agent layer. Each of the above layers will now be described.

[0018] Substrate: The substrate constituting the release film for producing a ceramic green sheet used in the method for producing a ceramic green sheet of the present invention is not particularly limited, and any substrate known in the art can be appropriately selected and used. Examples of such substrates include films made of plastics such as polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyolefins such as polypropylene and polymethylpentene, polycarbonate, and ethylene-vinyl acetate copolymers. These may be single-layer or multi-layers of two or more layers of the same or different materials. Among these, polyester films are preferred, with polyethylene terephthalate films being particularly preferred, and biaxially oriented polyethylene terephthalate films being even more preferred. Polyethylene terephthalate films are less likely to generate dust during processing and use, effectively preventing, for example, ceramic slurry coating defects due to dust.

[0019] In addition, this substrate can be subjected to a surface treatment such as an oxidation method or a primer treatment in order to improve adhesion to the release agent layer provided on at least one surface thereof. Examples of the oxidation method include corona discharge treatment, plasma discharge treatment, chromium oxidation treatment (wet), flame treatment, hot air treatment, ozone treatment, and ultraviolet irradiation treatment. These surface treatment methods are appropriately selected depending on the type of substrate film, but corona discharge treatment is generally preferred in terms of effectiveness and operability. There are no particular restrictions on the thickness of the substrate, and the thickness may be appropriately set based on mechanical strength, ease of handling during production and use, etc., but it is usually 10 to 300 μm, preferably 12 to 200 μm, and particularly preferably 15 to 125 μm.

[0020] The arithmetic mean roughness (Ra) of the surface of the substrate on the release agent layer side is preferably 0.1 to 70 nm, and more preferably 1 to 60 nm. An arithmetic mean roughness (Ra) of the surface of the substrate on the release agent layer side of 0.1 to 70 nm is preferred in terms of handling of the substrate, suppression of poor conduction, etc. Furthermore, substrates having a surface arithmetic mean roughness (Ra) of 1 to 70 nm are relatively easy and inexpensive to obtain, and are therefore preferred in terms of the availability and production costs of the release film for producing a ceramic green sheet used in the production method of the present invention.

[0021] The arithmetic mean roughness (Ra) of the surface of the substrate opposite the release agent layer side is preferably 5 to 70 nm, particularly preferably 10 to 60 nm. When the arithmetic mean roughness (Ra) of the surface of the substrate opposite the release agent layer side is equal to or greater than the above lower limit, blocking can be effectively suppressed during winding of the release film for producing a ceramic green sheet used in the production method of the present invention, and when it is equal to or less than the above upper limit, it becomes easy to smooth the surface of the release agent layer.

[0022] Release Agent Layer There are no particular restrictions on the material of the release agent layer constituting the release film for producing a ceramic green sheet used in the production method of the present invention. The Si amount before step a) on the surface of the release agent layer opposite to the substrate is ０ is 0.003 g / m ２ The amount of Si after step c) in the manufacturing method of the present invention having the above steps a) to c) is Si ｃ and the above Si ０ The difference between δSi and Si ｃ -Si ０ is -0.00027 g / m ２Any material can be used as long as it satisfies the above conditions. From the viewpoint of ease of production of the release film for producing a ceramic green sheet and appropriate control of the Si content, etc., it is preferable to form the release agent layer by coating a curable composition on a substrate and curing it, and it is particularly preferable to form the release agent layer by coating a photocurable and / or thermosetting curable composition and curing it. In other words, the release agent layer in the release film for producing a ceramic green sheet used in the production method of the present invention preferably contains a cured product of the curable composition.

[0023] Curable Composition The curable composition preferably used for forming the release agent layer in the release film for producing a ceramic green sheet used in the production method of the present invention preferably contains at least one reactive compound (a) having at least one reactive functional group selected from the group consisting of a (meth)acryloyl group, a hydroxyl group, and an epoxy group. By using a curable composition containing at least one reactive compound (a) having at least one reactive functional group selected from the group consisting of a (meth)acryloyl group, a hydroxyl group, and an epoxy group, the release agent layer of the release film for producing a ceramic green sheet of this embodiment can be easily formed with good controllability of the Si content, etc.

[0024] The above-mentioned curable composition may contain only one reactive compound (a) having at least one reactive functional group selected from the group consisting of (meth)acryloyl group, hydroxyl group and epoxy group, or may contain two or more reactive compounds (a) having at least one reactive functional group selected from the group consisting of (meth)acryloyl group, hydroxyl group and epoxy group.From the viewpoint of controlling various properties such as the curability, releasability and Si content of the release agent layer, it is preferable to use two or more reactive compounds (a) in combination, and particularly it is preferable to use the reactive silicone (a1) described below in combination with crosslinkable compound (a2), and it is further preferable to combine the film-forming compound (a3) ​​described below.

[0025] The curable composition may be composed solely of a reactive compound (a) having at least one reactive functional group selected from the group consisting of a (meth)acryloyl group, a hydroxyl group, and an epoxy group, or may contain other components such as a solvent, a radical initiator, a cationic initiator, a leveling agent, an antistatic agent, a dye, a pigment, etc. The total amount of the reactive compound (a) having at least one reactive functional group selected from the group consisting of a (meth)acryloyl group, a hydroxyl group, and an epoxy group used is preferably 50% by mass or more, particularly preferably 60 to 96% by mass, of the mass of the release agent layer.

[0026] Reactive Compound (a) The reactive compound (a) preferably used for forming the release agent layer in the release film for producing a ceramic green sheet used in the production method of the present invention has at least one reactive functional group selected from the group consisting of a (meth)acryloyl group, a hydroxyl group, and an epoxy group. By having at least one reactive functional group selected from the group consisting of a (meth)acryloyl group, a hydroxyl group, and an epoxy group, it is possible to impart photocurability and / or thermosetting properties to the curable composition.

[0027] The reactive compound (a) may have one or more reactive functional groups, but from the viewpoint of photocurability and / or thermosetting, it preferably has two or more reactive functional groups, more preferably has 2 to 15 reactive functional groups, and particularly preferably has 2 to 10 reactive functional groups. When the reactive compound (a) has two or more reactive functional groups, it may have two or more of the same type of reactive functional groups, or it may have a combination of two or more different types of reactive functional groups in total. From the viewpoint of curability, etc., when active energy rays are used, the reactive compound (a) preferably has a (meth)acryloyl group, and when thermosetting is used in combination, a material containing a hydroxyl group or an epoxy group can be appropriately selected.

[0028] Preferred examples of the reactive compound (a) include a reactive silicone (a1) having at least one reactive functional group selected from the group consisting of a (meth)acryloyl group, a hydroxyl group, and an epoxy group, and a siloxane skeleton, a reactive compound (a2) having the same reactive functional group as the reactive silicone (a1) and having a reactive functional group equivalent of 2000 or less, and a film-forming compound (a3) ​​having two or more (meth)acryloyl groups in one molecule. In the curable composition, it is preferable to use the reactive silicone (a1) and the reactive compound (a2) in combination, and it is also preferable to use the film-forming compound (a3) ​​in combination.

[0029] Reactive Silicone (a1) The curable composition preferably contains, as the reactive compound (a), a reactive silicone (a1) having at least one reactive functional group selected from the group consisting of a (meth)acryloyl group, a hydroxyl group, and an epoxy group, and a siloxane skeleton. The use of the reactive silicone (a1) imparts the desired releasability to the surface of the release agent layer, making it easier to release the ceramic green sheet. The amount of Si and its changes can also be appropriately controlled. The reactive silicone (a1) is not limited as long as it has at least one reactive functional group selected from the group consisting of a (meth)acryloyl group, a hydroxyl group, and an epoxy group, and a siloxane skeleton. By having at least one reactive functional group selected from the group consisting of a (meth)acryloyl group, a hydroxyl group, and an epoxy group, the reactive functional group reacts by irradiation with active energy rays or by a separate reaction step (e.g., a heating step), and the siloxane skeleton is incorporated into a crosslinked structure and fixed. This makes it possible to more effectively control the releasability of the release agent layer, the amount of Si and its change, etc. As the reactive functional group, an epoxy group is particularly preferred.

[0030] The reactive functional group may be introduced into one end of the siloxane skeleton, into both ends, or into a side chain. It is preferable that at least two reactive functional groups selected from the group consisting of (meth)acryloyl groups, hydroxyl groups, and epoxy groups are introduced into one molecule of the reactive silicone (a1). When two or more reactive functional groups are present, the reactive silicone (a1) may have two or more of the same type of reactive functional groups, or may have a combination of two or more different reactive functional groups in total. In addition to the reactive functional group selected from the group consisting of (meth)acryloyl groups, hydroxyl groups, and epoxy groups, the reactive silicone (a1) may further have a vinyl group, a maleimide group, a carboxyl group, an isocyanate group, or the like.

[0031] There are no particular restrictions on the molecular weight of the reactive silicone (a1), but from the viewpoints of appropriate release properties and controllability of the Si content and its changes, it is preferably 5,000 to 100,000, and particularly preferably 10,000 to 70,000.

[0032] In the curable composition, the reactive silicone (a1) may be used alone or in combination of two or more. The content of the reactive silicone (a1) in the curable composition is not particularly limited, but is preferably 0.1 to 20 mass %, particularly preferably 0.2 to 15 mass %, based on the total mass of the release agent layer.

[0033] Reactive Compound (a2) (Cross-Linkable Compound (a2)) The curable composition preferably contains, as the reactive compound (a), a reactive compound (a2) having the same reactive functional group as the reactive silicone (a1) and having a reactive functional group equivalent of 2000 g / mol or less. It is particularly preferable to use the reactive compound (a2) in combination with the reactive silicone (a1). The reactive compound (a2) functions as a cross-linking agent for the reactive silicone (a1) and the like, promoting the effects of the curable composition and allowing the reactive silicone (a1) and the like to be incorporated and fixed into a cross-linked structure. This further improves the performance of the ceramic green sheet, such as preventing contamination. In view of its function as a cross-linking agent, the reactive compound (a2) is also referred to herein as the "cross-linkable compound (a2)."

[0034] The reactive functional group equivalent of the reactive compound (a2) is 2000 g / mol or less, preferably 1800 g / mol or less, and particularly preferably 1700 g / mol or less. By having a reactive functional group equivalent of 2000 g / mol or less, the reactive compound (a2) has a sufficient number of (meth)acryloyl groups, hydroxyl groups, and / or epoxy groups to achieve appropriate crosslinking performance. The reactive compound (a2) preferably has a total of one or more reactive functional groups ((meth)acryloyl groups, hydroxyl groups, and / or epoxy groups), preferably 2 to 15, and particularly preferably 2 to 6. By having the number of reactive functional groups within the above range, more appropriate crosslinking performance can be achieved.

[0035] The molecular weight of the crosslinkable compound (a2) is not particularly limited, but from the viewpoint of crosslinking performance, etc., it is preferably from 150 to 4000, particularly preferably from 150 to 3000. The crosslinkable compound (a2) may have a siloxane skeleton, and in this case, by introducing a sufficient number of siloxane skeletons into the release agent layer together with the siloxane skeleton of the reactive silicone (a1), even more preferable release performance can be achieved.

[0036] In the curable composition, the crosslinkable compound (a2) may be used alone or in combination of two or more.The content of the crosslinkable compound (a2) in the curable composition is not particularly limited, but is preferably 0.08 to 99 mass%, more preferably 0.4 to 50 mass%, even more preferably 0.7 to 30 mass%, and particularly preferably 1.0 to 15 mass%, based on the total mass of the release agent layer.Furthermore, based on the amount of reactive silicone (a1) used, it is preferably used in an amount of 81 to 9900 mass parts, particularly preferably 85 to 1000 mass parts, based on 100 mass parts of reactive silicone (a1).

[0037] It is also preferable to use a compound with excellent film-forming properties as the reactive compound (a) in the curable composition. The compound with excellent film-forming properties may be either a compound having a (meth)acryloyl group or a compound having a hydroxyl group, but it is preferable to use a film-forming compound (a3) ​​having two or more (meth)acryloyl groups in one molecule. Film-Forming Compound (a3) ​​The curable composition preferably contains a film-forming compound (a3) ​​having two or more (meth)acryloyl groups in one molecule as the reactive compound (a). By containing a film-forming compound (a3) ​​having two or more (meth)acryloyl groups in one molecule, the curable composition can be cured by irradiation with active energy rays. The film-forming compound (a3) ​​may be any of a monomer, oligomer, or polymer, or a mixture thereof. The film-forming compound (a3) ​​is preferably a (meth)acrylic acid ester. Here, (meth)acrylic acid ester means both an acrylic acid ester and a methacrylic acid ester. The same applies to other similar terms.

[0038] The (meth)acrylic acid ester is preferably at least one selected from polyfunctional (meth)acrylate monomers and (meth)acrylate oligomers, particularly preferably at least one selected from difunctional or higher functional (meth)acrylate monomers and (meth)acrylate oligomers, and more preferably a trifunctional or higher functional (meth)acrylate monomer. By being difunctional or higher, and more preferably trifunctional or higher, the curable composition has excellent curability, and the surface of the resulting release agent layer also has excellent releasability.

[0039] The (meth)acryloyl group equivalent of the film-forming compound (a3) ​​is not particularly limited, and film-forming compounds (a3) ​​having a wide range of (meth)acryloyl group equivalents can be used as long as the conditions for the Si content and its change amount specified in the present invention are satisfied. From the viewpoint of realizing even better peelability and controllability of various properties such as the Si content, the (meth)acryloyl group equivalent of the film-forming compound (a3) ​​is preferably 300 g / mol or less, particularly preferably 260 g / mol or less.

[0040] Examples of polyfunctional (meth)acrylate monomers include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, neopentyl glycol adipate di(meth)acrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, dicyclopentanyl di(meth)acrylate, caprolactone-modified dicyclopentenyl di(meth)acrylate, ethylene oxide-modified phosphate di(meth)acrylate, allylated cyclohexyl di(meth)acrylate, and isocyanurate di(meth)acrylate. acrylate, trimethylolpropane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, propionic acid-modified dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propylene oxide-modified trimethylolpropane tri(meth)acrylate, tris((meth)acryloxyethyl)isocyanurate, propionic acid-modified dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, caprolactone-modified dipentaerythritol hexa(meth)acrylate, etc. These may be used alone or in combination of two or more.

[0041] Examples of polyfunctional (meth)acrylate oligomers include polyester acrylate oligomers, epoxy acrylate oligomers, urethane acrylate oligomers, polyether acrylate oligomers, polybutadiene acrylate oligomers, and silicone acrylate oligomers.

[0042] The polyester acrylate oligomer can be obtained, for example, by esterifying the hydroxyl groups of a polyester oligomer having hydroxyl groups at both ends, which is obtained by condensation of a polycarboxylic acid and a polyhydric alcohol, with (meth)acrylic acid, or by esterifying the terminal hydroxyl groups of an oligomer obtained by adding an alkylene oxide to a polycarboxylic acid, with (meth)acrylic acid.

[0043] Epoxy acrylate oligomers can be obtained, for example, by esterifying the oxirane ring of a relatively low molecular weight bisphenol epoxy resin or novolac epoxy resin with (meth)acrylic acid. Alternatively, carboxyl-modified epoxy acrylate oligomers can be used, in which epoxy acrylate oligomers are partially modified with dibasic carboxylic acid anhydrides.

[0044] The urethane acrylate oligomer can be obtained, for example, by esterifying a polyurethane oligomer obtained by reacting a polyether polyol or polyester polyol with a polyisocyanate with (meth)acrylic acid.

[0045] The polyether acrylate oligomer can be obtained by esterifying the hydroxyl groups of a polyether polyol with (meth)acrylic acid.

[0046] In the curable composition, the film-forming compound (a3) ​​may be used alone or in combination of two or more. The content of the film-forming compound (a3) ​​in the curable composition is not particularly limited, but is preferably 50 to 90 mass %, particularly preferably 60 to 85 mass %, based on the total mass of the release agent layer.

[0047] The release agent layer can be formed by coating the raw material of the release agent layer, preferably the above-mentioned curable composition, on at least one side of the substrate, then drying as necessary, and curing by irradiating with active energy rays such as light.If the reactive functional group of the reactive compound (a) is one that reacts with heat, the reaction can be caused by drying at this time, and preferably the reactive compound (a) having a siloxane skeleton can be incorporated into a crosslinked structure.There is no particular limitation on the coating method of the curable composition, and for example, gravure coating, bar coating, spray coating, spin coating, knife coating, roll coating, die coating, etc. can be used.

[0048] As the active energy ray, ultraviolet rays, electron beams, etc. are usually used. The irradiation dose of the active energy ray varies depending on the type of energy ray. For example, in the case of ultraviolet rays, the light dose is 10 to 1000 mJ / cm. ２ is preferred, particularly 20 to 500 mJ / cm ２ In the case of electron beams, the dose is preferably about 0.1 to 50 kGy.

[0049] The thickness of the release agent layer is preferably 0.05 to 2 μm, and particularly preferably 0.2 to 1.5 μm. A thickness of 0.05 μm or more is preferred from the viewpoint of smoothness of the release agent layer surface and suppression of pinholes and thickness unevenness of the ceramic green sheet. A thickness of 2 μm or less is preferred from the viewpoint of suppressing curling due to cure shrinkage of the release agent layer. It is also preferred from the viewpoint of suppressing blocking and charging.

[0050] Other Layers The release film for producing a ceramic green sheet used in the production method of the present invention may have layers other than the above-mentioned substrate and release agent layer, such as a protective layer, an adhesive layer, an antistatic layer, etc. The substrate and the release agent layer may be laminated directly, or may be laminated via another layer such as an adhesive layer.

[0051] In the method for producing a ceramic green sheet of the present invention, it is preferable to appropriately use the various release films for producing a ceramic green sheet described above in detail, but the release films that can be used in the production method of the present invention are not limited to these, and the Si amount on the surface of the release agent layer opposite to the substrate before step a) is Si ０ is 0.003 g / m ２ The amount of Si in the surface of the release agent layer opposite to the substrate after step c) is ｃ and the above Si ０ The difference between δSi and Si ｃ -Si ０ -0.00027 g / m ２ As long as the above can be achieved, various release films can be used appropriately.

[0052] The method for producing a ceramic green sheet of the present invention is a production method comprising the following steps a) to c): a) a step of applying a ceramic slurry onto a release film for producing a ceramic green sheet, b) a step of forming a ceramic green sheet from the ceramic slurry applied in step a), and c) a step of peeling the ceramic green sheet formed in step b) from the release film for producing a ceramic green sheet. ０ is 0.003 g / m ２ The amount of Si in the surface of the release agent layer opposite to the substrate after step c) is ｃ and the above Si ０ The difference between δSi and Si ｃ -Si ０ is -0.00027 g / m ２ As a result of the above, the method for producing a ceramic green sheet of the present invention allows the ceramic green sheet to be easily peeled from the release film, and changes in the peelability over time are small, so that excellent peelability can be stably achieved even long periods of time after the green sheet is applied. This simultaneously achieves technical effects of great practical value at a high level that exceeds the limits of conventional technology.

[0053] a) Coating of Ceramic Slurry In step a) of the method for producing a ceramic green sheet of the present invention, any technique conventionally used in this technical field for coating a ceramic slurry onto a release film for producing a ceramic green sheet can be used as appropriate, and for example, the following techniques can be used.

[0054] Ceramic Slurry There are no particular limitations on the ceramic slurry used in step a) of the present invention, and for example, any ceramic slurry that has been conventionally used in the art for producing ceramic green sheets can be used as appropriate.

[0055] The ceramic slurry preferably contains ceramic particles and a solvent, and the ceramic particles are preferably dispersed in the solvent. As the ceramic particles, inorganic compound particles that can form ceramics by sintering can be used, and examples of the inorganic compound include oxides, nitrides, oxynitrides, borides, etc. of metals or semimetals. More specific examples of the inorganic compound include barium titanate (BaTiO ３ ), calcium titanate (CaTiO ３ ), strontium titanate (SrTiO ３ ) or calcium zirconate (CaZrO ３ ), strontium zirconate (SrZrO ３ When these inorganic compounds are used as the main component of the ceramic particles, the ceramic particles may contain Mn, Mg, Si, Co, Ni, rare earth elements, or the like as a minor component in a content smaller than that of the main component.

[0056] The particle size of the ceramic particles is preferably 1 μm or less in terms of primary particles.

[0057] The solvent may be an organic solvent or an inorganic solvent such as an aqueous solvent, but an organic solvent is preferred from the viewpoint of ease of solvent removal when forming a ceramic green sheet in step b) described below. Conventional organic solvents can be used, and can be appropriately selected depending on the drying temperature during green sheet formation and the type of binder used. Aromatic, alcohol, ester, ketone, and hydrocarbon solvents are generally used, and a mixture of these can also be used. The boiling point of the solvent is not particularly limited, but is preferably 60 to 130°C, and particularly preferably 70 to 130°C.

[0058] From the viewpoint of ease of handling of the ceramic green sheet, the ceramic slurry preferably contains a binder in addition to the ceramic particles and the solvent. As the binder, various binders conventionally used in the production of ceramic green sheets in this technical field can be appropriately used, such as polyvinyl butyral, urethane resin, polyvinyl acetate resin, acrylic resin, cellulose resin, etc. Among them, polyvinyl butyral, acrylic, etc. are particularly preferably used. It is particularly preferable to use polyvinyl butyral with a hydroxyl value of 20 mol% or more. There are no particular restrictions on the amount of binder used, but it is preferably 3 to 20 parts by mass, and particularly preferably 5 to 15 parts by mass, per 100 parts by mass of the ceramic particles.

[0059] In addition to the ceramic particles, solvent, and optional binder, the ceramic slurry may contain other components such as a plasticizer, a surfactant, a dispersion stabilizer, an antistatic agent, etc. Suitable plasticizers include dibutyl phthalate, fatty acid esters, etc.

[0060] A ceramic slurry can be produced by stirring and mixing the above-mentioned ceramic particles, an organic solvent, and, if desired, other components such as a binder and a plasticizer. There are no particular limitations on the stirring and mixing method, and any method or device conventionally used in the art for producing ceramic slurries can be used as appropriate. For example, stirring and mixing can be performed using a ball mill. By using a ball mill, the particle size of the ceramic particles can also be adjusted.

[0061] In step a), the method for applying the ceramic slurry can be appropriately selected depending on the viscosity of the ceramic slurry and the type and thickness of the ceramic green sheet to be formed in step b). For example, an applicator, on-roll die coater, reduced pressure die coater, off-roll die coater, slit coater, curtain coater, lift coater, knife coater, cast coater, reverse roll coater, blade coater, screen printing method, etc. can be appropriately used.

[0062] b) Green Sheet Formation Step: In step b), the solvent is removed from the ceramic slurry applied in step a) by drying or the like to form a ceramic green sheet on the release film. The temperature and time for drying in step b) are not particularly limited, but drying can be carried out at a temperature of typically 60 to 100°C, preferably 70 to 100°C, for typically 30 to 300 seconds, preferably 30 to 200 seconds.

[0063] By setting the drying time in step b) to 30 seconds or more, the particles in the sheet can be uniformly and densely arranged by the time drying is completed, thereby reducing voids in the green sheet.By setting the drying time in step b) to 200 seconds or less, the production efficiency in the ceramic green sheet manufacturing process can be improved.

[0064] By setting the drying temperature in step b) to 70°C or higher, substantially no solvent remains in the ceramic green sheet, preventing the generation of voids in the ceramic during the firing step. Furthermore, by setting the drying temperature to 100°C or lower, the generation of swelling or depressions on the surface of the green sheet due to rapid evaporation of the solvent can be suppressed. Furthermore, multiple drying zones may be used, with different temperatures for each drying zone.

[0065] c) Peeling Step: In step c), the ceramic green sheet formed in step b) is peeled from the release film for producing a ceramic green sheet. The peeling method in step c) is not particularly limited and can be selected appropriately depending on the material and properties of the ceramic green sheet and subsequent steps. For example, the ceramic green sheet can be peeled by cutting the ceramic green sheet portion on the release film and then heating or deforming the release film. In the ceramic green sheet production method of the present invention, the use of the specific release film detailed above allows for low peel force (light peel) in step c). This effectively reduces damage to the ceramic green sheet. The peel force in the peeling step is preferably 5 to 100 (mN / 50 mm), and particularly preferably 10 to 50 (mN / 50 mm).

[0066] In the method for producing a ceramic green sheet of the present invention, by using the specific release film detailed above, it is possible to maintain a peel force that is little changed from the initial green sheet peel force, even if a long time has passed between steps a) and b) and step c). For example, even after storage at room temperature for one week following steps a) and b), the peel force in step c) is preferably 115% or less, and particularly preferably 110% or less, of the peel force when step c) is performed immediately after steps a) and b). By having the peel force in step c) after storage at room temperature for one week following step b) being 115% or less, the problem of green sheet breakage can be more effectively suppressed.

[0067] Electrode Printing Step, Half-Cutting Step, and Punching Step In addition to the above steps a) to c), the method for producing a ceramic green sheet of the present invention may further include a step of performing electrode printing, half-cutting, and / or punching after step b) and before step c).

[0068] Various ceramic products can be manufactured by firing the ceramic green sheets obtained by the manufacturing method of the present invention. According to the above embodiment, which has an electrode printing step after step b) and before step c), after electrode printing, multilayer ceramic capacitors and multilayer ceramic substrates can be manufactured through step c) (peeling), lamination and pressure bonding, cutting and separation, firing, and external electrode formation steps.

[0069] Various ceramic products can be manufactured by firing the ceramic green sheets obtained by the above manufacturing method. In manufacturing a multilayer ceramic capacitor, a step of printing internal electrodes on the green sheets can be added between the above steps b) and c). Then, the multilayer ceramic capacitor can be manufactured through step c) (peeling), lamination and pressure bonding, cutting and separation, firing, and external electrode formation steps.

[0070] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0071] In the following Examples and Comparative Examples, the evaluation of physical properties and characteristics was carried out by the following methods. (Si Amount) Using a fluorescent X-ray analyzer (manufactured by Rigaku Corporation, product name: ZSX Primus II), the intensity of silicon's specific X-ray Kα was measured under the following conditions to measure the amount of silicon (Si) on the release agent layer side surface of the release film sample. Analysis area: 30 mmφ Analysis element: Si Analysis crystal: PET Output: 50 kV, 60 mA According to the calibration curve, an intensity of silicon's specific X-ray Kα of 1.0 kcps corresponds to a silicon amount of 0.003 g / m ２ Based on this, the strength (kcps) was calculated as the silicon content (g / m ２ ) was converted.

[0072] (Peel Force) 1) Preparation of Ceramic Slurry Barium titanate (BT-01, manufactured by Sakai Chemical Industry Co., Ltd.), polyvinyl butyral (S-LEC BH-S, manufactured by Sekisui Chemical Co., Ltd.), dibutyl phthalate, toluene, and ethanol were mixed in a mass ratio of 45:3.6:0.9:25:25 to prepare a ceramic slurry that would serve as the raw material for the ceramic green sheet. 2) Formation of Ceramic Green Sheet The ceramic slurry prepared in 1) above was applied to the release agent layer side of a release film sample for producing a ceramic green sheet with an applicator to a thickness of 50 μm, and then dried at 70° C. for 2 minutes to form a ceramic green sheet with a thickness of 10 μm. 3) Measurement of peel strength of green sheet The release film sample and the ceramic green sheet formed thereon in the above 2) were cut into strips of 50 mm x 200 mm, and the green sheet was peeled off from the release film at an angle of 180° using a Tensilon (A&D Co., Ltd.: RTG-1210) to measure the peel strength.

[0073] Details of each component such as resin used in the release agent layer in the examples and comparative examples are as follows: (a3) Multifunctional acrylate 1 Shin-Nakamura Chemical Co., Ltd., trade name: NK Ester A-9300 Tris-(2-acryloxyethyl)isocyanurate (number of functional groups: 3) Acrylic equivalent: 141 g / mol (a3) ​​Multifunctional acrylate 2 Shin-Nakamura Chemical Co., Ltd., trade name: NK Ester A-TMM-3LM-N Pentaerythritol tri- and tetraacrylate (number of functional groups: 3 and 4) Acrylic equivalent: 93.7 g / mol (a3) ​​Multifunctional acrylate 3 Shin-Nakamura Chemical Co., Ltd., trade name: NK Ester A-DCP Tricyclodecane dimethanol diacrylate (number of functional groups: 2) Acrylic equivalent: 304 g / mol (a3) ​​Multifunctional acrylate 4 Shin-Nakamura Chemical Co., Ltd., trade name: NK Ester A-GLY-9E Ethoxylated glycerin triacrylate (number of functional groups: 3) Acrylic equivalent: 217 g / mol (a3) ​​Multifunctional acrylate 5, manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: NK Ester A-HD-N 1,6-Hexanediol diacrylate (number of functional groups: 2) Acrylic equivalent: 113 g / mol (a1) Epoxy-modified silicone 1 Arakawa Chemical Industries, Ltd., product name: SILICOREASE UV POLY201 Dimethyl silicone, alicyclic epoxy silicone block copolymer (a2) Epoxy-modified silicone 2 Shin-Etsu Chemical Co., Ltd., product name: Shin-Etsu Silicone KR-470 Alicyclic epoxy group-containing cyclic siloxane tetrafunctional oligomer Epoxy equivalent: 200 g / mol (a2) Epoxy-modified silicone 3 Shin-Etsu Chemical Co., Ltd., product name: Shin-Etsu Silicone X-22-169AS Dual-end type / alicyclic epoxy-modified silicone oil Epoxy equivalent: 500 g / mol (a2) Epoxy-modified silicone 4 Shin-Etsu Chemical Co., Ltd., product name: Shin-Etsu Silicone X-22-169B Dual-end type / alicyclic epoxy-modified silicone oil Epoxy equivalent: 1700 g / mol Epoxy-modified silicone 5 manufactured by Shin-Etsu Chemical Co., Ltd., product name: Shin-Etsu Silicone KF-102 Side chain type / alicyclic epoxy-modified silicone oil Epoxy equivalent: 3600 g / mol Cationic initiator 1 manufactured by Sanshin Chemical Industry Co., Ltd., product name: San-Aid SI-100 Radical initiator 1 manufactured by IGM RESINS, product name: Esacure ONE α-hydroxyketone type photopolymerization initiator

[0074] [Example 1] A curable composition for a release agent layer was prepared by blending polyfunctional acrylate 1, epoxy-modified silicone 1, epoxy-modified silicone 2, cationic initiator 1, and radical initiator 1 in the mass ratios shown in Table 1. A polyethylene terephthalate film having a thickness of about 30 μm and an arithmetic mean roughness (Ra) of the surface of about 20 nm was used as the substrate. The curable composition prepared above was applied to one side of the substrate, dried at 100°C for 15 seconds, and then irradiated with ultraviolet light using a high-pressure mercury lamp (integrated light intensity: about 40 mJ / cm). ２ ) and cured to form a release agent layer, thereby producing a release film having a substrate and a release agent layer provided on one side of the substrate. The amount of Si on the surface of the release layer of the produced release film was measured by the above method, and the initial Si amount Si ０Then, 1) ceramic slurry was prepared and 2) ceramic green sheet was formed by the above method, and then 3) peel strength of the green sheet was measured to obtain the initial sheet peel strength. Separately, an unused release film sample and the ceramic slurry obtained by the above 1) ceramic slurry preparation were used to form the above 2) ceramic green sheet, and after storing for one week in a constant temperature and humidity environment of 23±2°C x 50±5% RH, the above 3) peel strength of the green sheet was measured to obtain the sheet peel strength after one week. Furthermore, after measuring the sheet peel strength after one week (after peeling the green sheet), the amount of Si was measured by the above method for the release layer surface of the release film, and the Si amount after peeling Si ｃ The results are shown in Table 1.

[0075] [Examples 2 to 4 and Comparative Examples 1 to 4] Release films were produced and evaluated in the same manner as in Example 1, except that the formulation of the curing agent composition for the release agent layer was changed to that shown in Table 1. The results are shown in Table 1.

[0076]

[0077] The ceramic green sheet manufacturing method of the present invention realizes technical effects of great practical value at a high level that surpasses the limitations of conventional techniques, such as easy peeling of a ceramic green sheet formed on a release film, little change in peelability over time, and stable excellent peelability even long periods after the green sheet is applied, and can be suitably used in the manufacture of various ceramic products. For example, the method significantly improves the productivity of various ceramic products such as multilayer ceramic capacitors and multilayer ceramic substrates, and is particularly suitable for use in the manufacture of these products.

[0078] 11: Release film for producing ceramic green sheet 12: Release agent layer 13: Substrate

Claims

1. a) applying a ceramic slurry onto a release film for producing a ceramic green sheet; b) forming a ceramic green sheet from the ceramic slurry applied in the a) step; and c) peeling the ceramic green sheet formed in the b) step from the release film for producing the ceramic green sheet; A method for producing a ceramic green sheet comprising: the release film for producing a ceramic green sheet has a base material and a release agent layer provided on at least one side of the base material, The amount of Si in the surface of the release agent layer opposite to the substrate before the step a) ０ is 0.003 g / m ２ That's all, The amount of Si in the surface of the release agent layer opposite to the substrate after the step c) is ｃ and the above Si ０ The difference between δSi and Si ｃ -Si ０ is -0.00027 g / m ２ That's all. A method for producing the ceramic green sheet.

2. 2. The method for producing a ceramic green sheet according to claim 1, wherein the ceramic slurry contains polyvinyl butyral having a hydroxyl value of 20 mol % or more.

3. 3. The method for producing a ceramic green sheet according to claim 1, further comprising a step of printing internal electrodes on the ceramic green sheet between step b) and step c).

4. A method for producing a ceramic product, comprising the step of producing a ceramic green sheet by the method for producing a ceramic green sheet according to claim 1 or 2.

5. The method for producing a ceramic product according to claim 4, further comprising the step of firing the ceramic green sheet.

6. The method for producing a ceramic product according to claim 4, wherein the ceramic product is a multilayer ceramic capacitor or a multilayer ceramic substrate.