Release film for ceramic green sheet manufacturing

Abstract

The present invention addresses the problem of providing a release film for ceramic green sheet production, the release film having a substrate and a release agent layer, making it easy to peel the green sheet off, and effectively suppressing contamination of the green sheet. Said problem is solved by a release film for ceramic green sheet production, the release film having a substrate and a release agent layer provided on at least one side of the substrate, wherein the diiodomethane sliding angle of the surface of the release agent layer opposite the substrate is 33° or less.

Description

[Technical Field]

[0001] The present invention relates to a release film for producing ceramic green sheets, and more specifically to a release film for producing ceramic green sheets that allows easy release of the green sheets, effectively suppresses contamination of the green sheets, 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] Release films for producing ceramic green sheets have been used in the production of sheet-like ceramic members. For example, to produce multilayer ceramic products such as multilayer ceramic capacitors and multilayer ceramic substrates, ceramic green sheets are formed on a release film for producing ceramic green sheets, and then multiple ceramic green sheets are stacked and fired. In recent years, with the miniaturization and improved performance of electronic devices, multilayer ceramic capacitors and multilayer ceramic substrates have become smaller and more multilayered. To achieve this, ceramic green sheets must be thinner. To prevent defects such as pinholes and uneven thickness in thin ceramic green sheets and to effectively prevent breakage when thin ceramic green sheets are peeled from the release film, a release film for producing ceramic green sheets has been proposed, which includes a substrate and a release agent layer of specific components, in which the arithmetic mean roughness (Ra) and maximum projection height (Rp) of the release agent layer on the side opposite the substrate are each equal to or less than a predetermined value, and the arithmetic mean roughness (Ra) and maximum projection height (Rp) of the substrate on the side opposite the release agent layer are each within a predetermined numerical range (see, for example, Patent Document 1).

[0003] In order to miniaturize and increase the number of layers in multilayer 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 used to produce ceramic green sheets can cause misalignment and reduce positional accuracy, and a solution is needed. 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 achieve both reduced migration of contaminants to the green sheet and easy releasability of the green sheet. [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 substrate and a release agent layer, and which allows easy peeling of the green sheet while effectively suppressing contamination of the green sheet. [Means for solving the problem]

[0006] As a result of extensive research, the inventors have discovered 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 setting the diiodomethane sliding angle of the release agent layer on the surface opposite the substrate to a predetermined value or less, it is possible to achieve a balance between reducing the migration of contaminants to the green sheet and making the green sheet easily releasable at a high level that exceeds the limits of conventional technology, 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 film for producing a ceramic green sheet, wherein the diiodomethane sliding angle on the surface of the release agent layer opposite to the substrate is 33° or less.

[0007] Below, [2] to

[11] 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 diiodomethane sliding angle on the surface of the release agent layer opposite the substrate is 10° to 33°. [3] The release film for producing a ceramic green sheet according to [1] or [2], wherein the water sliding angle of the surface of the release agent layer opposite to the substrate is 85° or less. [4] The release film for producing a ceramic green sheet according to any one of [1] to [3], characterized in that 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 in terms of mass ratio. [5] The release film for producing a ceramic green sheet according to [4], 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). [6] The release film for producing a ceramic green sheet according to [5], wherein the curable composition further contains a film-forming compound (a3) ​​having two or more (meth)acryloyl groups in one molecule. [7] The release film for producing a ceramic green sheet according to any one of [1] to [6], wherein the arithmetic mean roughness (Ra) of the surface of the base material on the release agent layer side is 1 to 70 nm. [8] The release film for producing a ceramic green sheet according to any one of [1] to [7], which is used in producing a multilayer ceramic capacitor or a multilayer ceramic substrate. [9] a) applying a ceramic slurry onto the release film for producing a ceramic green sheet according to any one of [1] to [7]; b) forming a ceramic green sheet from the ceramic slurry applied in the a) step; and c) peeling the ceramic green sheet formed in step b) from the release film for producing the ceramic green sheet; The method for producing a ceramic green sheet has the steps of:

[10] 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 [9].

[11] The method for producing a ceramic product according to

[10] , wherein the ceramic product is a multilayer ceramic capacitor or a multilayer ceramic substrate. [Effects of the Invention]

[0008] The release film for producing ceramic green sheets of the present invention simultaneously realizes technical effects of great practical value at a high level that surpasses the limitations of conventional technology, such as easy release of the ceramic green sheets formed thereon and effective suppression of contamination of the ceramic green sheets, and is therefore suitable for use in the production of various ceramic products, such as multilayer ceramic capacitors and multilayer ceramic substrates, which are composed of thin ceramic layers and require high positional precision during production. [Brief explanation 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 INVENTION

[0010] The present invention provides 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 film for producing a ceramic green sheet, wherein the diiodomethane sliding angle on the surface of the release agent layer opposite to the substrate is 33° 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 consist 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 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 known in the art can be appropriately selected and used. Examples of such substrates include films made of polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyolefins such as polypropylene and polymethylpentene, polycarbonate, and plastics such as 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.

[0012] Furthermore, in order to improve adhesion to the release agent layer provided on at least one surface of the substrate, the substrate may be subjected to a surface treatment such as an oxidation method or a primer treatment. 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 set appropriately based on factors such as mechanical strength and ease of handling during production and use, but it 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 0.1 to 70 nm, and more preferably 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 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 from the viewpoints 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, particularly preferably from 10 to 60 nm. When the arithmetic mean roughness (Ra) of the surface of the substrate opposite to 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 of the present invention, and when it is equal to or less than the above upper limit, it becomes easier to smooth the surface of the release agent layer.

[0015] Release agent layer There are no particular restrictions on the material of the release agent layer that constitutes the release film for producing ceramic green sheets of the present invention, and any material can be used as long as it meets the condition that the diiodomethane sliding angle on the surface opposite the substrate is 33° or less. From the viewpoint of ease of production of the release film for producing ceramic green sheets and appropriate control of the diiodomethane sliding angle, etc., it is preferable to form the release agent layer by applying a curable composition to the 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. That is, it is preferable that the release agent layer in the present invention contains a cured product of the curable composition.

[0016] curable composition The curable composition preferably used in the present invention for forming the release agent layer 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 diiodomethane sliding angle, etc.

[0017] The curable composition may contain only one reactive compound (a) having at least one reactive functional group selected from the group consisting of (meth)acryloyl, hydroxyl, and epoxy groups, or may contain two or more reactive compounds (a) having at least one reactive functional group selected from the group consisting of (meth)acryloyl, hydroxyl, and epoxy groups. From the viewpoint of controlling various properties of the release agent layer, such as curability, releasability, and sliding angle, it is preferable to use two or more reactive compounds (a) in combination, and it is particularly preferable to use a combination of the reactive silicone (a1) and the crosslinkable compound (a2) described below, and it is also preferable to combine a film-forming compound (a3).

[0018] 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, or a pigment. The total 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 preferably 50% by mass or more, particularly preferably 60 to 96% by mass, of the mass of the release agent layer.

[0019] Reactive Compound (a) The reactive compound (a) preferably used for forming 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, preferably has 2 to 15 reactive functional groups, and more 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., the reactive compound (a) preferably has a (meth)acryloyl group when active energy rays are used, and 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 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 a film-forming compound (a3) ​​having two or more (meth)acryloyl groups in one molecule. In the curable composition, it is preferable to use a combination of the reactive silicone (a1) and the reactive compound (a2), and it is also preferable to use a combination of the film-forming compound (a3).

[0022] Reactive silicone (a1) The curable composition preferably 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 (a1) having a siloxane skeleton. By using the reactive silicone (a1), the surface of the release agent layer is given the desired releasability, making it possible to further facilitate the release of the ceramic green sheet. 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 has a siloxane skeleton. By containing 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 with the active energy ray or a separate reaction step (e.g., a heating step) to incorporate the siloxane skeleton into a crosslinked structure and fix it, thereby more effectively preventing the reactive silicone (a1) from contaminating the ceramic green sheet formed on the release agent layer. As the reactive functional group, an epoxy group is particularly preferred.

[0023] The reactive functional group may be introduced into one end of the siloxane skeleton, into both ends, or into a side chain. It is preferred 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, they may be two or more of the same type, or a combination of two or more different reactive functional groups may be present. In addition to the reactive functional group selected from the group consisting of a (meth)acryloyl group, a hydroxyl group, and an epoxy group, the compound may further have a vinyl group, a maleimide group, a carboxyl group, an isocyanate group, or the like.

[0024] There are no particular restrictions on the molecular weight of the reactive silicone (a1), but from the viewpoint of achieving appropriate release properties and stain prevention, it is preferably from 5,000 to 100,000, and particularly preferably from 10,000 to 70,000.

[0025] 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 %, and particularly preferably 0.2 to 15 mass %, based on the total mass of the release agent layer.

[0026] Reactive compound (a2) (crosslinking 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 preferably having a reactive functional group equivalent of 2000 g / mol or less. It is particularly preferred to use the reactive compound (a2) in combination with the reactive silicone (a1). The reactive compound (a2) functions as a crosslinking agent for the reactive silicone (a1), etc., promoting the effect of the curable composition and allowing the reactive silicone (a1), etc., to be incorporated and fixed into a crosslinked structure. This makes it possible to more effectively suppress contamination of the ceramic green sheet. In view of its function as a crosslinking agent, the reactive compound (a2) is also referred to herein as the "crosslinkable compound (a2)."

[0027] The reactive functional group equivalent weight of the reactive compound (a2) is preferably 2000 or less, more preferably 1000 or less, even more preferably 500 or less, and particularly preferably 300 or less. By having a reactive functional group equivalent weight of 2000 or less, the number of (meth)acryloyl groups, hydroxyl groups, and / or epoxy groups sufficient to achieve suitable crosslinking performance will be present. 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. When the number of reactive functional groups is within the above range, more appropriate crosslinking performance can be achieved.

[0028] There are no particular restrictions on the molecular weight of the crosslinkable compound (a2), but from the viewpoint of crosslinking performance and the like, it is preferably from 150 to 3,500, and particularly preferably from 150 to 1,500. The crosslinkable compound (a2) 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 (a1), even more preferable release performance can be achieved.

[0029] 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 %, and particularly preferably 0.4 to 50 mass %, based on the total mass of the release agent layer. Furthermore, based on the amount of reactive silicone (a1) used, the content is preferably 81 to 9,900 mass parts, and particularly preferably 85 to 1,000 mass parts, based on 100 mass parts of reactive silicone (a1).

[0030] Film-forming compound (a3) It is also preferable to use a compound having excellent film-forming properties as the reactive compound (a) in the curable composition. The compound having 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. That is, the curable composition preferably contains, as the reactive compound (a), a film-forming compound (a3) ​​having two or more (meth)acryloyl groups in one molecule. By including the 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 one of a monomer, an oligomer, or a polymer, or a mixture thereof. The film-forming compound (a3) ​​is preferably a (meth)acrylic acid ester. Here, the term "(meth)acrylic acid ester" refers to both an acrylic acid ester and a methacrylic acid ester. The same applies to other similar terms.

[0031] 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 trifunctional or higher, the curable composition has excellent curability, and the surface of the resulting release agent layer also has excellent releasability.

[0032] 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, and caprolactone-modified dipentaerythritol hexa(meth)acrylate. These may be used alone or in combination of two or more.

[0033] 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.

[0034] The polyester acrylate oligomer can be obtained, for example, by esterifying the hydroxyl groups of a polyester oligomer having hydroxyl groups at both ends, 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.

[0035] 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.

[0036] 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.

[0037] The polyether acrylate oligomer can be obtained by esterifying the hydroxyl groups of a polyether polyol with (meth)acrylic acid.

[0038] The (meth)acryloyl group equivalent of the film-forming compound (a3) ​​is not particularly limited, but from the viewpoint of curability, it is preferably 100 to 500 g / mol, and particularly preferably 100 to 300 g / mol.

[0039] 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.

[0040] 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, followed by 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 is induced by drying at this time, and preferably the reactive compound (a) having a siloxane skeleton can be incorporated into a crosslinked structure. There are no particular limitations on the method for 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.

[0041] 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, and particularly 20 to 500 mJ / cm 2 In the case of electron beams, the dose is preferably about 0.1 to 50 kGy.

[0042] The diiodomethane sliding angle of the surface of the release agent layer constituting the release film for producing a ceramic green sheet of the present invention opposite to the substrate is 33° or less. The diiodomethane sliding angle of the release agent layer on the surface opposite the substrate is 33° or less, which, combined with other technical features of the present invention, allows the release film for producing ceramic green sheets of the present invention to achieve excellent technical effects of great practical value, such as being able to achieve a high level of ease in peeling the ceramic green sheets formed thereon and suppressing contamination of the ceramic green sheets. The mechanism by which a diiodomethane sliding angle of 33° or less on the surface of the release agent layer opposite the substrate enables both ease of peeling of the ceramic green sheet and prevention of contamination of the ceramic green sheet to be achieved at a higher level is not entirely clear. However, the sliding angle of the release agent layer, which is an indicator of adhesion energy, is closely related to the surface condition of the release agent layer, and is also correlated with releasability, which may be closely related to the surface condition of the release agent layer, and contamination of the ceramic green sheet and other substrates, with the sliding angle of a specific liquid (diiodomethane) having a particularly high correlation. Therefore, it is presumed that there is an optimal value for the diiodomethane sliding angle that can achieve both releasability and contamination resistance.

[0043] The diiodomethane sliding angle of the surface of the release agent layer opposite the substrate can be measured by a method conventionally known in the art, for example, using a commercially available contact angle / sliding angle measuring device. More specifically, it can be measured by the method described in the examples of the present specification.

[0044] The diiodomethane sliding angle of the surface of the release agent layer opposite to the substrate is preferably from 10° to 33°, and particularly preferably from 15° to 30°. The diiodomethane sliding angle of the surface of the release agent layer opposite the substrate can be appropriately adjusted by adjusting the type and amount of materials constituting the release agent layer and the coating weight of the release agent layer. In particular, it 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 preferably having a reactive functional group equivalent of 2000 or less.

[0045] The release film for producing ceramic green sheets of the present invention is only required to have a diiodomethane sliding angle on the surface of the release agent layer opposite the substrate that satisfies the above-mentioned conditions, and no other restrictions are imposed, but the water sliding angle on the surface of the release agent layer opposite the substrate is preferably 85° or less, more preferably 80° or less, and even more preferably 75° or less. The water sliding angle of the release agent layer on the surface opposite the substrate is 85° or less, which, combined with other technical features of this embodiment, allows the release film for producing ceramic green sheets of this embodiment to achieve excellent technical effects of great practical value, such as being able to achieve a higher level of ease in peeling the ceramic green sheets formed thereon and suppressing contamination of the ceramic green sheets. The mechanism by which a water sliding angle of 85° or less on the surface of the release agent layer opposite the substrate can achieve both ease of peeling of the ceramic green sheet and prevention of contamination of the ceramic green sheet at a higher level is not entirely clear, but the sliding angle of the release agent layer, which is an indicator of adhesion energy, is closely related to the surface condition of the release agent layer, and is also correlated with releasability, which may be closely related to the surface condition of the release agent layer, and contamination of the ceramic green sheet and other substrates.The sliding angle of a specific liquid (water) that has hydrogen bonding strength has the second highest correlation after diiodomethane, and it is therefore presumed that there is an optimal value for the water sliding angle that can achieve both releasability and contamination resistance.

[0046] The water sliding angle of the surface of the release agent layer opposite the substrate can be measured by a method conventionally known in the art, for example, using a commercially available contact angle / sliding angle measuring device. More specifically, it can be measured by the method described in the examples of the present specification.

[0047] The water contact angle of the surface of the release agent layer opposite the substrate can be appropriately adjusted by adjusting the type and amount of materials constituting the release agent layer and the coating amount of the release agent layer. In particular, it 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 preferably having a reactive functional group equivalent of 2000 g / mol or less.

[0048] 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 surface of the release agent layer and suppression of pinholes and thickness unevenness in 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.

[0049] 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 or via another layer such as an adhesive layer.

[0050] Release film for ceramic green sheet manufacturing The release film for producing ceramic green sheets of the present invention allows easy release of the ceramic green sheets formed thereon and can effectively prevent contamination of the ceramic green sheets, 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.

[0051] There are no particular limitations 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) a step of peeling the ceramic green sheet formed in the step b) from the release film for producing the ceramic green sheet.

[0052] By firing the ceramic green sheet obtained by the above-described manufacturing method, various ceramic products can be manufactured. In manufacturing a multilayer ceramic capacitor, a step of printing internal electrodes on the green sheets is inserted 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 a multilayer ceramic capacitor. [Example]

[0053] 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.

[0054] In the following Examples and Comparative Examples, the physical properties and characteristics were evaluated by the following methods. (water sliding angle) Using a contact angle / sliding angle measuring device (Kyowa Interface Science DM-500), a 6 μL droplet of ultrapure water was placed on the release agent layer surface of the sample release film (the side opposite the substrate), and the stage was tilted intermittently at a speed of 1 degree / second, then held still for 5 seconds. The angle at which the water droplet began to move was taken as the sliding angle. Measurements were performed five times, and the average of the five measurements was taken as the sliding angle of water. (Sliding angle of diiodomethane) The sliding angle of diiodomethane was measured in the same manner as in the measurement of the sliding angle of water described above, except that 2.1 μL of diiodomethane was used instead of 6 μL of ultrapure water.

[0055] (Back contamination) Using Teranishi Chemical Industry's oil-based magic marker (large, red, writing line width: 5 x 8 mm), a line 8 mm wide x 70 mm long was drawn on the side of the substrate opposite the release agent layer side, and after 1 minute, the central 50 mm long section was observed for 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% (Tape peeling force) The peel sample was placed on a horizontal table with the release agent layer facing up, and adhesive tape "No. 31B" (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 adhesive tape. 2 A load was applied so that the temperature was 70°C for 20 hours. Thereafter, 180° peeling was carried out at a pulling speed of 300 mm / min using a tensile tester, and the peel force was determined by dividing the average peel load in the region where peeling became stable by the width of the adhesive tape.

[0056] 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., product name: NK Ester A9300 Trifunctional isocyanuric acrylate monomer (tris-(2-acryloxyethyl) isocyanurate) (a1) Epoxy-modified silicone 1 Arakawa Chemical Industries, Ltd., product name: Silicolyse 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 (a2) Epoxy-modified silicone 3 Shin-Etsu Chemical Co., Ltd., product name: Shin-Etsu Silicone X-22-169AS Double-ended / alicyclic epoxy-modified silicone oil (a2) Epoxy-modified silicone 4 Shin-Etsu Chemical Co., Ltd., product name: Shin-Etsu Silicone X-22-169B Double-ended / alicyclic epoxy-modified silicone oil (a2) Epoxy-modified silicone 5 Shin-Etsu Chemical Co., Ltd., product name: Shin-Etsu Silicone KF-102 Side chain / alicyclic epoxy modified silicone oil 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 photopolymerization initiator

[0057] [Example 1] Polyfunctional acrylate 1, 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 approximately 30 μm and a surface arithmetic mean roughness (Ra) of approximately 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: approximately 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 release films produced above were evaluated for sliding angle, backside contamination, and tape peel strength in water and diiodomethane using the methods described above. The results are shown in Table 1.

[0058] [Example 3 to 4, and Comparative Example 1] 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.

[0059] [Table 1] [Industrial Applicability]

[0060] The release film for producing ceramic green sheets of the present invention allows for easy release of the ceramic green sheets formed thereon, and simultaneously realizes technical effects of great practical value at a high level that surpasses the limitations of conventional technology, such as effectively suppressing contamination of the ceramic green sheets. Since it 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]

[0061] 11: Release film for ceramic green sheet manufacturing 12: Release agent layer 13: Base material

Claims

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 diiodomethane sliding angle of the surface of the release agent layer opposite to the substrate is 33° or less; 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 in terms of mass ratio; the curable composition contains, as the reactive compound (a), 0.2 to 15 mass% of a dimethylsilicone-alicyclic epoxy silicone block copolymer (a1) based on the total mass of the release agent layer, 0.4 to 26 mass% of at least one compound (a2) selected from an alicyclic epoxy group-containing cyclic siloxane tetrafunctional oligomer and a dual-end / alicyclic epoxy-modified silicone oil based on the total mass of the release agent layer, and 60 to 85 mass% of a film-forming compound (a3) ​​having two or more (meth)acryloyl groups in one molecule based on the total mass of the release agent layer.

2. 2. The release film for producing a ceramic green sheet according to claim 1, wherein the surface of the release agent layer opposite the substrate has a diiodomethane sliding angle of 10° to 33°.

3. 3. The release film for producing a ceramic green sheet according to claim 1, wherein the surface of the release agent layer opposite the substrate has a water sliding angle of 85° or less.

4. 3. The release film for producing a ceramic green sheet according to claim 1, wherein the surface of the substrate facing the release agent layer has an arithmetic mean roughness (Ra) of 1 to 70 nm.

5. 3. The release film for producing a ceramic green sheet according to claim 1, which is used in producing a multilayer ceramic capacitor or a multilayer ceramic substrate.

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