Release film for producing ceramic green sheet

Abstract

To provide a release film for producing a ceramic green sheet, which is easy to peel off the green sheet and effectively suppresses contamination or curling of the green sheet.SOLUTION: There is provided a release film for producing a ceramic green sheet which has a base material and a release agent layer provided on at least one side of the base material, wherein the release agent layer contains a cured product of a curable composition, the curable composition comprises 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, at least a part of the reactive compound (a) is a film-forming compound (a1) having two or more (meth)acryloyl groups in one molecule, the average equivalent weight of the acrylic groups in the film-forming compound (a1) is 100 g / mol or more and 300 g / mol or less and the ratio of the bifunctional compound in the film-forming compound (a1) is 40 mass% or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a release film for producing a ceramic green sheet, and more specifically, to a release film for producing a ceramic green sheet, which allows easy peeling of the green sheet, effectively suppresses contamination of the green sheet, and blocks and curls of the release film, and is particularly suitable for use in the production of ceramic products that require high positional accuracy in the production of multilayer ceramic capacitors, multilayer ceramic substrates, and the like. [Background technology]

[0002] In the manufacture of sheet-like ceramic members, a release film for producing a ceramic green sheet has been used. For example, in order to manufacture a multilayer ceramic product such as a multilayer ceramic capacitor or a multilayer ceramic substrate, a ceramic green sheet is formed on a release film for producing a ceramic green sheet, and a plurality of the obtained ceramic green sheets 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 smaller and more multilayered. To achieve multilayering, ceramic green sheets are required to be thinner, and 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 a specific component, and 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 order to miniaturize and multilayer laminated ceramic capacitors and multilayer ceramic substrates, extremely high positional accuracy is required during lamination, but contaminants from the release agent layer of the release film for producing ceramic green sheets can cause misalignment and reduce the positional accuracy, and a solution is required. Such contaminants are presumed to be unreacted silicone components remaining in the release agent layer, but simply reducing the amount of silicone components used in producing the release agent layer reduces the releasability of the green sheet, making it difficult to simultaneously reduce the migration of contaminants to the green sheet and ensure easy releasability of the green sheet. In addition, from the viewpoint of the handling properties of the release film, it has been desired to prevent blocking and curling. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2013 / 145865 A1 Brochure Summary of the Invention [Problem to be solved by the invention]

[0005] In view of the above technical background, the present invention aims to provide a release film for producing a ceramic green sheet, which has a base material and a release agent layer, and which allows easy peeling of the green sheet while effectively suppressing contamination and curling of the green sheet. [Means for solving the problem]

[0006] As a result of intensive research, the inventors have found that in 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 forming the release agent layer from a cured product of a curable composition containing a reactive compound having a specific acrylic equivalent, it is possible to achieve a high level of balance that exceeds the limits of conventional technology, reducing the migration of contaminants to the green sheet, preventing blocking of the release film, suppressing curling, and making the green sheet easily releasable, and have thus completed the present invention. That is, the present invention provides: [1] A release film for producing a ceramic green sheet, comprising a substrate and a release agent layer provided on at least one side of the substrate, 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, at least a part of the reactive compound (a) is a film-forming compound (a1) having two or more (meth)acryloyl groups in one molecule, the average equivalent weight of the acrylic group of the film-forming compound (a1) is 100 g / mol or more and 300 g / mol or less, and the proportion of bifunctional compounds in the entire film-forming compound (a1) is 40 mass% or less.

[0007] Below, [2] to [7] are each a preferred aspect or embodiment of the present invention. [2] The release film for producing a ceramic green sheet according to [1], wherein the curable composition further contains, as the reactive compound (a), at least one reactive silicone (a2) 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 (a3) ​​having the same reactive functional group as the reactive silicone (a2) and having a reactive functional group equivalent of 1000 g / mol or less. [3] The release film for producing a ceramic green sheet according to [1] or [2], wherein the arithmetic mean roughness (Ra) of the surface of the base material on the release agent layer side is 1 to 70 nm. [4] The release film for producing a ceramic green sheet according to any one of [1] to [3], which is used in producing a multilayer ceramic capacitor or a multilayer ceramic substrate. [5] a) applying a ceramic slurry onto the release film for producing a ceramic green sheet according to any one of [1] to [3]; 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; The method for producing a ceramic green sheet comprising the steps of: [6] 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 [5]. [7] The method for producing a ceramic product according to [6], wherein the ceramic product is a multilayer ceramic capacitor or a multilayer ceramic substrate. Effect of the Invention

[0008] The release film for producing ceramic green sheets of the present invention realizes technical effects having high practical value at a high level that exceeds the limits of conventional technology, such as easy peeling of the ceramic green sheets formed thereon and effectively suppressing contamination of the ceramic green sheets, blocking of the release film, and curling of the film, and can be suitably used in the production of various ceramic products. For example, it is particularly suitable for use in the production of ceramic products such as multilayer ceramic capacitors and multilayer ceramic substrates, which are composed of thin ceramic layers and require high positional accuracy in production. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing one embodiment of a release film for producing a ceramic green sheet. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The present invention provides a release film for producing a ceramic green sheet, comprising a base material and a release agent layer provided on at least one side of the base material, 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, at least a part of the reactive compound (a) is a film-forming compound (a1) having two or more (meth)acryloyl groups in one molecule, the average equivalent weight of the acrylic group of the film-forming compound (a1) is 100 g / mol or more and 300 g / mol or less, and the proportion of bifunctional compounds in the entire film-forming compound (a1) is 40 mass% or less. That is, the release film for producing a ceramic green sheet of the present invention has a substrate and a release agent layer. The release film for producing a ceramic green sheet of the present invention only needs to have a substrate and a release agent layer, and may or may not have other layers. Therefore, the release film for producing a ceramic green sheet of the present invention may be composed of only a substrate and a release agent layer, or may have other layers such as an antistatic layer in addition to the substrate and the release agent layer. Each of the above layers will now be described.

[0011] Base material The substrate constituting the release film for producing ceramic green sheets of the present invention is not particularly limited, and any substrate may be appropriately selected from those conventionally known as substrates in the technical field. 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, and may be a single layer or a multilayer of two or more layers of the same or different types. Among these, polyester films are preferred, polyethylene terephthalate films are particularly preferred, and biaxially stretched polyethylene terephthalate films are even more preferred. Polyethylene terephthalate films are less likely to generate dust during processing, use, etc., and therefore, for example, ceramic slurry coating defects due to dust, etc. can be effectively prevented.

[0012] In addition, this substrate may be subjected to a surface treatment such as an oxidation method or a primer treatment in order to improve adhesion to a release agent layer provided on at least one surface of the substrate. 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 generally, corona discharge treatment is preferably used in terms of effectiveness and operability. There is no particular restriction on the thickness of the substrate, which may be appropriately set based on mechanical strength and ease of handling during production and use, but is usually 10 to 300 μm, preferably 12 to 200 μm, and particularly preferably 15 to 125 μm.

[0013] The arithmetic mean roughness (Ra) of the surface of the substrate on the release agent layer side is preferably from 0.1 to 70 nm, and more preferably from 1 to 60 nm. The arithmetic mean roughness (Ra) of the surface of the substrate on the release agent layer side is preferably 0.1 to 70 nm in terms of handling of the substrate, suppression of poor electrical continuity, etc. In addition, substrates having a surface arithmetic mean roughness (Ra) of 1 to 70 nm are relatively easy and inexpensive to obtain, and are therefore also preferable in terms of availability and production costs of the release film for producing the ceramic green sheet of the present invention.

[0014] The arithmetic mean roughness (Ra) of the surface of the substrate opposite to the release agent layer side is preferably from 5 to 70 nm, and particularly preferably from 10 to 60 nm. When the arithmetic mean roughness (Ra) of the surface of the substrate opposite the release agent layer side is not less than the above-mentioned lower limit, blocking during winding of the release film for producing a ceramic green sheet of the present invention can be effectively suppressed, while when it is not more than the above-mentioned upper limit, it becomes easy to smooth the surface of the release agent layer.

[0015] Release agent layer The release agent layer constituting the release film for producing a ceramic green sheet of the present invention contains a cured product of a curable composition. It is preferable to form the release agent layer by applying the curable composition onto a substrate and curing it, and it is particularly preferable to form the release agent layer by applying a photocurable and / or thermosetting curable composition and curing it.

[0016] curable composition The curable composition used in the present invention for forming the release agent layer contains at least 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, at least a part of the reactive compound (a) is a film-forming compound (a1) having two or more (meth)acryloyl groups in one molecule, and the average acrylic group equivalent of the film-forming compound (a1) is 100 g / mol or more and 300 g / mol or less, and the ratio of bifunctional compounds in the total film-forming compound (a1) is 40% mass% or less. Here, the "average" acrylic group equivalent of the film-forming compound (a1) means the weighted average value of the acrylic group equivalent of each film-forming compound (a1) based on the amount (mass) used when multiple film-forming compounds (a1) are used. . When the reactive compound (a) satisfies the above conditions, in combination with other technical features of the present invention, it is possible to form a release agent layer of the release film for producing a ceramic green sheet of the present invention, which simultaneously achieves technical effects of great practical value at a high level that exceeds the limits of conventional technology, such as easy peeling of the ceramic green sheet and effectively suppressing contamination of the ceramic green sheet, blocking of the release film, and curling of the film.

[0017] The curable composition may contain only one type of 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 two or more types of reactive compounds (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, as long as the curable composition contains at least one film-forming compound (a1) having an average acrylic group equivalent of 100 g / mol or more and 300 g / mol or less and having two or more (meth)acryloyl groups in one molecule, as 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. From the viewpoint of controlling various properties such as the curability and releasability of the release agent layer, it is preferable to use a combination of two or more reactive compounds (a). For example, it is preferable to contain a reactive silicone (a2) having a siloxane skeleton described below in addition to a film-forming compound (a1) having two or more (meth)acryloyl groups in one molecule and having an average acrylic group equivalent of 100 g / mol to 300 g / mol, and further to combine it with a reactive compound (a3) ​​having the same reactive functional group as the reactive silicone (a2) and having a reactive functional group equivalent of 1000 g / mol or less.

[0018] The curable composition may be composed of only 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, and a pigment. The amount of reactive compound (a) having at least one reactive functional group selected from the group consisting of (meth)acryloyl group, hydroxyl group, and epoxy group is preferably 50% by mass or more in total based on the mass of the release agent layer. By using the reactive compound (a) in an amount of 50% by mass or more based on the mass of the release agent layer, the release film for producing ceramic green sheets of the present invention can more effectively realize the ease of peeling the ceramic green sheet formed thereon and the prevention of contamination of the ceramic green sheet. The amount of 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 more preferably 50% or more by mass, and particularly preferably 60 to 96% by mass, of the release agent layer.

[0019] Reactive Compound (a) The reactive compound (a) used in the formation of the release agent layer in 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.

[0020] The reactive compound (a) may have one or more reactive functional groups, but from the viewpoint of photocurability and / or thermosetting property, 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 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, it is preferable that the reactive compound (a) has a (meth)acryloyl group. When heat curing is also used, a material containing a hydroxyl group or an epoxy group can be appropriately selected.

[0021] Preferred examples of the reactive compound (a) include a film-forming compound (a1) having two or more (meth)acryloyl groups in one molecule, a reactive silicone (a2) 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 a reactive compound (a3) ​​having the same reactive functional group as the reactive silicone (a2) and having a reactive functional group equivalent of 1000 g / mol or less. The curable composition contains a film-forming compound (a1), and preferably further contains a reactive silicone (a2), and it is particularly preferred to use a reactive compound (a3) ​​in combination.

[0022] Film-forming compound (a1) As the reactive compound (a) in the curable composition, it is preferable to use a compound having excellent film-forming properties, and from this viewpoint, a film-forming compound (a1) having two or more (meth)acryloyl groups in one molecule is used. By including the film-forming compound (a1) having two or more (meth)acryloyl groups in one molecule, the curable composition can be cured with good curability by irradiation with active energy rays.

[0023] The average acrylic equivalent of the film-forming compound (a1) is 100 g / mol or more and 300 g / mol or less, and the ratio of bifunctional compounds in the total film-forming compound (a1) is 40 mass% or less. By having the average acrylic equivalent of the film-forming compound (a1) be 100 g / mol or more and 300 g / mol or less, the release film for producing a ceramic green sheet of the present invention is easy to peel off the ceramic green sheet formed thereon, and can effectively suppress contamination of the ceramic green sheet, blocking of the release film, and curling of the film. The mechanism by which the average acrylic equivalent of the film-forming compound (a1) is 100 g / mol or more and 300 g / mol or less and the proportion of bifunctional compounds in the total film-forming compound (a1) is 40 mass % or less allows the releasability of the ceramic green sheet, prevention of contamination of the ceramic green sheet, blocking of the release film, and prevention of curling of the film to be balanced at a high level is not necessarily clear, but it is possible that the curing state of the film-forming compound (a1) affects the surface state of the release agent layer, and therefore it is presumed that there is an optimal range for the acrylic equivalent of the film-forming compound (a1), which has a significant impact on the curing state. The average acrylic equivalent of the film-forming compound (a1) is preferably from 100 g / mol to 280 g / mol, particularly preferably from 100 g / mol to 260 g / mol.

[0024] The film-forming compound (a1) may be any one of a monomer, an oligomer, or a polymer, or may be a mixture thereof. The film-forming compound (a1) is preferably a (meth)acrylic acid ester. Here, the (meth)acrylic acid ester means both an acrylic acid ester and a methacrylic acid ester. The same applies to other similar terms. 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 tridifunctional or higher (meth)acrylate monomers and (meth)acrylate oligomers, and more preferably a trifunctional or higher (meth)acrylate monomer. By being trifunctional or higher, it becomes easier to set the acrylic equivalent within the above range, and the curability of the curable composition becomes excellent, and the releasability of the surface of the obtained release agent layer also becomes excellent.

[0025] 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 phosphoric acid 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, and the like. These may be used alone or in combination of two or more.

[0026] Examples of the polyfunctional (meth)acrylate oligomer include polyester acrylate oligomers, epoxy acrylate oligomers, urethane acrylate oligomers, polyether acrylate oligomers, polybutadiene acrylate oligomers, and silicone acrylate oligomers.

[0027] 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.

[0028] The epoxy acrylate oligomer can be obtained, for example, by reacting (meth)acrylic acid with the oxirane ring of a relatively low molecular weight bisphenol epoxy resin or novolac epoxy resin to esterify it. In addition, a carboxyl-modified epoxy acrylate oligomer obtained by partially modifying an epoxy acrylate oligomer with a dibasic carboxylic acid anhydride can also be used.

[0029] 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.

[0030] The polyether acrylate oligomer can be obtained by esterifying the hydroxyl groups of a polyether polyol with (meth)acrylic acid.

[0031] In the curable composition, the film-forming compound (a1) may be used alone or in combination of two or more kinds. The content of the film-forming compound (a1) in the curable composition is not particularly limited, but is preferably 50 to 90 mass %, and particularly preferably 60 to 85 mass %, based on the total mass of the release agent layer.

[0032] Reactive Silicone (a2) It is preferable that the curable composition further contains, as the reactive compound (a), 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 reactive silicone (a2) having a siloxane skeleton. By using the reactive silicone (a2), the surface of the release agent layer can be given the desired releasability, making it easier to peel off the ceramic green sheet. The reactive silicone (a2) 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 has a siloxane skeleton. By having at least one reactive functional group selected from the group consisting of (meth)acryloyl group, hydroxyl group, and epoxy group, the reactive functional group reacts by irradiation with active energy rays or by a separate reaction step (for example, a heating step), and the siloxane skeleton is incorporated into a crosslinked structure and fixed. This makes it possible to more effectively prevent the reactive silicone (a2) from contaminating the ceramic green sheet formed on the release agent layer. As the reactive functional group, an epoxy group is particularly preferred.

[0033] The reactive functional group may be introduced into one end of the siloxane skeleton, may be introduced into both ends, or may be introduced into a side chain. At least one reactive functional group selected from the group consisting of (meth)acryloyl group, hydroxyl group, and epoxy group is preferably introduced into one molecule of the reactive silicone (a2) in an amount of two or more. When the reactive silicone (a2) has two or more reactive functional groups, the reactive silicone (a2) 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 a (meth)acryloyl group, a hydroxyl group, and an epoxy group, it may further have a vinyl group, a maleimide group, a carboxyl group, an isocyanate group, or the like.

[0034] There are no particular limitations on the molecular weight of the reactive silicone (a2), but from the standpoint of appropriate releasability and stain prevention, it is preferably from 5,000 to 100,000, and particularly preferably from 10,000 to 70,000.

[0035] In the curable composition, the reactive silicone (a2) may be used alone or in combination of two or more kinds. The content of the reactive silicone (a2) in the curable composition is not particularly limited, but is preferably from 0.1 to 20 mass %, and particularly preferably from 0.2 to 15 mass %, based on the total mass of the release agent layer.

[0036] Crosslinking compound (a3) The curable composition preferably contains, as the reactive compound (a), a reactive compound (a3) ​​having the same reactive functional group as the reactive silicone (a2) and having a reactive functional group equivalent of 1000 g / mol or less. It is particularly preferable to use the reactive compound (a3) ​​in combination with the reactive silicone (a2). The reactive compound (a3) ​​functions as a crosslinking agent for the reactive silicone (a2) etc., promotes the effect of the curable composition, and can incorporate and fix the reactive silicone (a2) etc. into a crosslinked structure, thereby making it possible to more effectively suppress contamination of the ceramic green sheet.

[0037] The reactive functional group equivalent of the reactive compound (a3) ​​is 1000 g / mol or less, preferably 500 g / mol or less, particularly preferably 300 g / mol or less. By having a reactive functional group equivalent of 1000 g / mol or less, the resin has a sufficient number of (meth)acryloyl groups, hydroxyl groups, and / or epoxy groups to achieve appropriate crosslinking performance, and can more effectively reduce the migration of contaminants to the green sheet while also ensuring easy peelability of the green sheet. The reactive compound (a3) ​​preferably has a total of 1 or more reactive functional groups ((meth)acryloyl groups, hydroxyl groups, and / or epoxy groups), preferably 2 to 15, and particularly preferably 2 to 6. When the number of reactive functional groups is within the above range, more appropriate crosslinking performance can be achieved.

[0038] The molecular weight of the crosslinkable compound (a3) ​​is not particularly limited, but from the viewpoint of crosslinking performance, etc., it is preferably from 150 to 3,500, and particularly preferably from 150 to 1,500. The crosslinkable compound (a3) ​​may have a siloxane skeleton. In this case, by introducing a sufficient amount of siloxane skeleton into the release agent layer together with the siloxane skeleton of the reactive silicone (a2), more preferable release performance can be achieved.

[0039] In the curable composition, the crosslinkable compound (a3) ​​may be used alone or in combination of two or more kinds. The content of the crosslinkable compound (a3) ​​in the curable composition is not particularly limited, but is preferably 0.08 to 99 mass%, particularly preferably 0.4 to 50 mass%, based on the total mass of the release agent layer. In relation to the amount of reactive silicone (a2) used, the mass ratio of reactive silicone (a2) / reactive compound (a3) ​​is preferably 0.1 or more.

[0040] By using a reactive silicone (a2) 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 a reactive compound (a3) ​​having the same reactive functional group as the reactive silicone (a2) and having a reactive functional group equivalent of 1000 g / mol or less, in a ratio such that the mass ratio of reactive silicone (a2) / reactive compound (a3) ​​is 0.1 or more, in combination with other technical features of this embodiment, the release film for producing a ceramic green sheet of this embodiment can achieve excellent technical effects that are of great practical value, such as being able to achieve a higher level of both ease of peeling off the ceramic green sheet formed thereon and suppression of contamination of the ceramic green sheet. The mass ratio of the reactive silicone (a2) / the reactive compound (a3) ​​is more preferably 0.1-10, and particularly preferably 0.15-5.

[0041] The release agent layer can be formed by applying the raw material of the release agent layer, preferably the above-mentioned curable composition, to at least one surface of the substrate, and then drying as necessary and curing by irradiation 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 the reactive compound (a) preferably having a siloxane skeleton can be incorporated into a crosslinked structure. There is no particular limit to the method of applying the curable composition, and for example, gravure coating, bar coating, spray coating, spin coating, knife coating, roll coating, die coating, etc. can be used.

[0042] As the active energy ray, ultraviolet rays, electron beams, etc. are usually used. The irradiation amount of the active energy ray varies depending on the type of energy ray. For example, in the case of ultraviolet rays, the light amount is 10 to 1000 mJ / cm. 2 is preferable, and particularly 20 to 500 mJ / cm 2 In the case of electron beams, the dose is preferably about 0.1 to 50 kGy.

[0043] 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 preferable from the viewpoint of smoothness of the surface of the release agent layer and suppression of pinholes and thickness unevenness of the ceramic green sheet. A thickness of 2 μm or less is preferable from the viewpoint of suppression of curling due to cure shrinkage of the release agent layer. It is also preferable from the viewpoint of suppression of blocking and charging.

[0044] Other layers The release film for producing a ceramic green sheet 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 to each other, or may be laminated via another layer such as an adhesive layer.

[0045] Release film for ceramic green sheet manufacturing The release film for producing a ceramic green sheet of the present invention allows easy release of the ceramic green sheet formed thereon and can effectively suppress contamination of the ceramic green sheet, and therefore can be suitably used in the production of ceramic green sheets used in various ceramic products, such as multilayer ceramic capacitors or multilayer ceramic substrates.

[0046] There is no particular limitation on the method for producing a ceramic green sheet using the release film for producing a ceramic green sheet of the present invention. For example, the release film for producing a ceramic green sheet of the present invention can be preferably used in a production method having the following steps. a) A step of applying a ceramic slurry onto the release film for producing a ceramic green sheet of the present invention. b) forming a ceramic green sheet from the ceramic slurry applied in the a) step; c) peeling the ceramic green sheet formed in the b) step from the release film for producing the ceramic green sheet.

[0047] By firing the ceramic green sheet obtained by the above-mentioned production method, various ceramic products can be produced. In manufacturing a multilayer ceramic capacitor, a step of printing internal electrodes on the green sheet is provided between the above steps b) and c), followed by step c) (peeling), lamination and pressure bonding, cutting and separation, firing, and external electrode formation steps to manufacture the multilayer ceramic capacitor. EXAMPLES

[0048] The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto. It is not something that is done.

[0049] In the following Examples and Comparative Examples, the physical properties and characteristics were evaluated by the following methods. (Backside contamination) Using Terani Chemical Industry's oil-based marker ink (large, red, writing line width: 5 x 8 mm), a line 8 mm wide x 70 mm long was drawn on the side opposite the release agent layer of the substrate, and after 1 minute, a central 50 mm long section was observed for the line width and evaluated according to the following criteria. 5: Remaining line width is 90% or more 4: There are areas where the remaining line width is between 70% and 90%. 3: There are areas where the remaining line width is between 50% and 70%. 2: There are areas where the remaining line width is 20% or more but less than 50%. 1: There are areas where the remaining line width is between 0% and 20%. The occurrence of blocking was also evaluated. (curl) A sample film was cut into an area of ​​10 cm x 10 cm and placed on a glass plate with the release layer surface facing up. A metal plate of 10 cm x 10 cm (mass: 300 g) was placed on half of the area of ​​the measurement sample, and the curl was measured at two vertices on the side where the metal plate was not placed. The location where the metal plate was placed was moved, and the curl was evaluated at two vertices on each of the four sides (a total of eight vertices). 〇: The total curl of 8 places is 0 to 50 mm or less △: The total length of the 8 curls is between 50mm and 100mm ×: The total length of the eight curls is greater than 100 mm (Tape peeling force) The release sample was placed on a horizontal table with the release agent layer facing up, and adhesive tape "Polyester Adhesive Tape No. 31B75 High" (brand name, manufactured by Nitto Denko Corporation) was attached to the release agent layer side and cut to a size of 200 mm x 50 mm. Further, 20 g / cm was applied to the top of the adhesive tape. 2 A load was placed so that the specimen was aged at 70° C. for 20 hours. Thereafter, 180° peeling was performed at a tensile speed of 300 mm / min using a tensile tester, and the peel force was calculated by dividing the average peel load in the region where peeling became stable by the width of the adhesive tape.

[0050] Details of each of the constituent components such as resins used in the release agent layer in the examples and comparative examples are as follows. (a1) Multifunctional acrylate 1 Manufactured by Shin-Nakamura Chemical Co., Ltd. Product name: NK Ester A-TMM-3LM-N Pentaerythritol tri- and tetraacrylate (functional groups: 3 and 4) Acrylic equivalent: 93.7g / mol (a1) Multifunctional acrylate 2 Product name: NK Ester A-DCP, manufactured by Shin-Nakamura Chemical Co., Ltd. Tricyclodecane dimethanol diacrylate (functional groups: 2) Acrylic equivalent: 304g / mol (a1) Multifunctional acrylate 3 Product name: NK Ester A9300, manufactured by Shin-Nakamura Chemical Co., Ltd. Tris-(2-acryloxyethyl)isocyanurate (functional groups: 3) Acrylic equivalent: 141g / mol (a1) Multifunctional acrylate 4 Manufactured by Toagosei Co., Ltd., product name: Aronix M-327 Trisacryloyloxyethyl isocyanurate (functional groups: 3) modified with 3 caprolactones per molecule Acrylic equivalent: 255g / mol (a1) Multifunctional acrylate 5 Product name: NK Ester A-DPH, manufactured by Shin-Nakamura Chemical Co., Ltd. Dipentaerythritol polyacrylate (functional groups: 5 and 6) Acrylic equivalent: 95.4g / mol (a1) Multifunctional acrylate 6 Product name: NK Ester AT-20E, manufactured by Shin-Nakamura Chemical Co., Ltd. Ethoxylated trimethylolpropane triacrylate (functional groups: 3) Acrylic equivalent: 392g / mol (a2) Epoxy-modified silicone 1 Arakawa Chemical Industries, Ltd., Product name: Silicolyse UV POLY201 Dimethyl silicone, alicyclic epoxy silicone block copolymer (a3) Epoxy-modified silicone 2 Manufactured by Shin-Etsu Chemical Co., Ltd., Product name: Shin-Etsu Silicone KR-470 Alicyclic epoxy group-containing cyclic siloxane tetrafunctional oligomer Epoxy equivalent: 200g / mol Cationic initiator 1 Sanshin Chemical Industry Co., Ltd. Product name: San-Aid SI-100 Radical initiator 1 Made by IGM RESINS Product name: Esacure ONE α-Hydroxyketone type photoinitiator

[0051] [Example 1] Multifunctional acrylates 1 and 2, epoxy modified silicone 1, epoxy modified silicone 2, cationic initiator 1, and radical initiator 1 were mixed in the mass ratios shown in Table 1 to prepare a curable composition for the release agent layer. A polyethylene terephthalate film having a thickness of about 30 μm and a surface arithmetic mean roughness (Ra) of about 20 nm was used as the substrate. The curable composition prepared above was applied to one surface of the substrate, and after drying at 100°C for 15 seconds, ultraviolet light was irradiated using a high-pressure mercury lamp (accumulated light amount: about 40 mJ / cm 2 ) and curing 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 release film produced above was evaluated for backside contamination, curl, and tape peeling strength by the methods described above. The results are shown in Table 1.

[0052] [Examples 2 to 5 and Comparative Examples 1 to 2] A release film was produced 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, and then evaluated. The results are shown in Table 1.

[0053] [Table 1] [Industrial Applicability]

[0054] The release film for producing ceramic green sheets of the present invention allows easy release of the ceramic green sheets formed thereon, while also effectively suppressing contamination of the ceramic green sheets, blocking of the release film, and curling of the film, thereby simultaneously achieving technical effects of great practical value at a high level that surpasses the limitations of conventional technology. Since the film can be suitably used in the production of various ceramic products, it has high applicability in various fields of industry, including the electrical and electronics industry, electronic parts industry, machinery industry, and automotive industry. [Explanation of symbols]

[0055] 11: Release film for ceramic green sheet manufacturing 12: Release agent layer 13: Base material

Claims

1. A release film for manufacturing a ceramic green sheet, comprising a base material and a release agent layer provided on at least one of the base materials, wherein the release agent layer contains a cured product of a curable composition, and the curable composition contains at least 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, and at least a part of the reactive compound (a) is a film-forming compound (a1) having two or more (meth)acryloyl groups in one molecule, and the average equivalent weight of the acrylic groups of the film-forming compound (a1) is 100 g / mol or more and 300 g / mol or less, and the proportion of the bifunctional compound in all the film-forming compounds (a1) is 40% by mass or less. A release film for manufacturing a ceramic green sheet.

2. The release film for manufacturing a ceramic green sheet according to claim 1, wherein the curable composition further contains at least one reactive silicone (a2) having at least one reactive functional group selected from the group consisting of (meth)acryloyl group, hydroxyl group, and epoxy group and having a siloxane skeleton, and at least one reactive compound (a3) having the same reactive functional group as the reactive silicone (a2) and having a reactive functional group equivalent weight of 1000 g / mol or less.

3. The release film for manufacturing a ceramic green sheet according to claim 1, wherein the arithmetic mean roughness (Ra) of the surface of the base material on the release agent layer side is 1 to 70 nm.

4. The release film for manufacturing a ceramic green sheet according to any one of claims 1 to 3, which is used for manufacturing a multilayer ceramic capacitor or a multilayer ceramic substrate.

5. a) A step of applying a ceramic slurry on the release film for manufacturing a ceramic green sheet according to any one of claims 1 to 3, 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 manufacturing a ceramic green sheet. A method for manufacturing a ceramic green sheet, comprising the steps of:

6. A method for manufacturing a ceramic product, comprising a step of manufacturing a ceramic green sheet by the method for manufacturing a ceramic green sheet according to claim 5.

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

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