WO2020050081A1

WO2020050081A1 - Mold release film for ceramic green sheet production

Info

Publication number: WO2020050081A1
Application number: PCT/JP2019/033275
Authority: WO
Inventors: 充晴中谷; 悠介柴田; 量之應矢
Original assignee: 東洋紡株式会社
Priority date: 2018-09-03
Filing date: 2019-08-26
Publication date: 2020-03-12
Also published as: CN113246263B; CN112672866A; SG10202103428TA; JP7092221B2; JP2021091223A; JP2021079699A; KR102342605B9; KR20210038720A; JP6813124B2; KR102335931B1; CN113246263A; JP6841375B1; CN112672866B; MY195706A; MY194550A; KR102342605B1; JPWO2020050081A1; PH12021550425A1; KR20210036404A; SG11202101981QA

Abstract

[Problem] To provide a mold release film for ceramic green sheet production, which is suppressed in deterioration of the surface roughness of a mold release layer due to aggregation during drying, thereby having high smoothness, and which has excellent releasability by adjusting the amount of a silicone component in the surface of the mold release layer. [Solution] A mold release film for ceramic green sheet production, which uses a polyester film as a base material, and which is configured such that: the base material has a surface layer A on at least one surface, said surface layer A substantially containing no particles; and a mold release layer is superposed on the surface of the surface layer A on at least one surface directly or with another layer being interposed therebetween. The mold release layer is obtained by curing a composition that contains a binder component and a silicone-based mold release agent; the Si element ratio in the mold release layer surface is from 2.0 at% to 10.0 at% (inclusive); and the mold release layer surface has a maximum profile peak height (P) of 50 nm or less and an area average roughness (Sa) of 1.5 nm or less.

Description

Release film for ceramic green sheet production

The present invention relates to a release film for producing a ceramic green sheet, and more particularly, to an ultra-thin layer capable of producing a film in which occurrence of process defects due to pinholes and thickness unevenness is suppressed when producing an ultra-thin ceramic green sheet. And a release film for producing a ceramic green sheet.

In recent years, with the miniaturization and large capacity of multilayer multilayer ceramic capacitors (abbreviated as MLCC), thinning of ceramic green sheets is required. Multilayer multilayer ceramic capacitors form a ceramic green sheet by coating and drying a slurry containing a ceramic component such as barium titanate and a binder resin on a release film, and printing electrodes on the resulting ceramic green sheet. After that, it is manufactured by peeling off from the release film, laminating and pressing ceramic green sheets, degreasing and firing, and then applying an external electrode.

In order to reduce the size and capacity of the MLCC, it is necessary to reduce the thickness of the ceramic green sheet. The thickness of the ceramic green sheet is reduced to 1.0 μm or less, and further to 0.6 μm or less. Further thinning is progressing. However, when the ceramic green sheet is made thinner, there is a problem that defects such as pinholes and cracks are likely to occur due to extremely minute projections on the release film and a force at the time of peeling from the release film.

解決 In order to solve these problems, a film in which a release layer is provided on a polyester film and the surface of the release layer is highly smoothed has been proposed as a release film used for molding a ceramic green sheet. Patent Document 1 discloses that a smoothing layer is provided on the surface of a polyester film, and then a release layer is provided on the smoothing layer. Patent Document 2 discloses that a release layer composed of a (meth) acrylate and a silicone-based component is formed with a thickness of 0.3 μm or more. According to the descriptions of Patent Document 1 and Patent Document 2, it is disclosed that the arithmetic average roughness Ra of the release layer surface can be 8 nm or less and the maximum protrusion height Rp can be 50 nm or less.

However, according to the techniques described in Patent Documents 1 and 2, since the thickness of the resin layer (release layer and smoothing layer) laminated on the polyester film is large, it takes a long time to cure, and the amount of the organic solvent used is also small. There were issues such as a large environmental load due to the increase. In addition, curling of the obtained release film due to the large thickness of the release layer sometimes becomes a problem. Further, in the techniques described in these documents, there is a concern that the amount of the silicone-based component contained in the release layer is large, the elastic modulus of the surface of the release layer is low, and peeling becomes unstable.

The following proposals have also been made for the release layer of the release film for molding ceramic green sheets. Patent Literature 3 proposes a non-silicone release layer containing no silicone in the release layer. Patent Document 4 proposes a film using a silicone resin as a release layer. However, if the release layer is a non-silicone-based release layer as in the technique described in Patent Document 3, the peeling force when peeling the ceramic green sheet is increased, and there is a problem that the ceramic green sheet having a reduced thickness is damaged. Further, in the release layer of the silicone resin as described in Patent Document 4, the peeling force when peeling the ceramic green sheet is small, but generally, since the glass transition temperature of the silicone resin is below room temperature, There is a problem that the release force is unstable because the release layer is deformed at the time of peeling because the elastic modulus is low.

特許 Furthermore, Patent Document 5 proposes a release layer containing an alkyd resin, an amino resin, and a modified silicone resin. Further, Patent Document 6 proposes a release layer containing a melamine resin and a polyorganosiloxane. By mainly containing a crosslinked body such as melamine resin as a binder of the release layer and adding a silicone resin as a release component, it is possible to increase the elastic modulus of the release layer and achieve both deformability and releasability. Proposed.

However, as described in Patent Documents 5 and 6, when the release layer contains a binder resin and a silicone resin, the solubility of the binder resin and the silicone resin in an organic solvent and the surface tension of the solution are reduced. Due to such a large difference, the compatibility deteriorates during drying, and the respective resins coagulate to form projections, which causes a problem of deteriorating the surface roughness of the release layer surface. When molding a ceramic green sheet having a thickness of 1.0 μm or less, or even 0.6 μm or less, even if the minute surface roughness is deteriorated, pinholes and the like are generated and the defective rate of the obtained multilayer ceramic capacitor is deteriorated. , Further smoothness was required.

JP 2014-177093 A International Publication No. WO 2013/145864 JP 2010-144046 A JP 2012-207126 A JP-A-9-239913 JP 2017-7226 A

In view of the above circumstances, the present invention, even if the release layer of the release film for producing a ceramic green sheet is a release layer obtained by curing a composition containing at least a binder component and a silicone-based release agent, By controlling the deterioration of the surface roughness due to the aggregation during the drying of the components and having a high smoothness, and by adjusting the amount of the silicone component on the surface of the release layer, the release for the ceramic green sheet production with excellent releasability is achieved. It is intended to provide a mold film.

That is, the present invention has the following configurations.
1. Using a polyester film as a base material, the base material has a surface layer A substantially free of particles on at least one surface, and is released on at least one surface of the surface layer A directly or via another layer. A release film in which layers are laminated, wherein the release layer is formed by curing a composition containing a binder component and a silicone-based release agent, and the Si element ratio on the release layer surface is 2.0 at% or more. A release film for producing a ceramic green sheet, which has a maximum protrusion height (P) of 50 nm or less and a region average roughness (Sa) of 1.5 nm or less at 10.0 at% or less, and a release layer surface.
2. 2. The release film for producing a ceramic green sheet as described in 1 above, wherein the silicone release agent is a silicone resin having a polyether moiety or a carboxyl group.
3. 3. The release film for producing a ceramic green sheet according to the above 1 or 2, wherein the silicone-based release agent-derived component is contained in the release layer in an amount of 1 to 15 mg / m ² .
4. 4. The release film for producing a ceramic green sheet according to any one of the first to third aspects, wherein the binder component contains a resin having a long-chain alkyl group and / or a silicone skeleton.
5. A method for producing a ceramic green sheet using the release film for producing a ceramic green sheet according to any one of the first to fourth aspects, wherein the molded ceramic green sheet has a thickness of 0.2 μm or more. A method for producing a ceramic green sheet having a thickness of 1.0 μm.
6. A method for manufacturing a ceramic capacitor employing the method for manufacturing a ceramic green sheet according to the fifth aspect.

According to the present invention, even a release layer containing at least a binder component and a silicone-based release agent has high smoothness by suppressing deterioration of surface roughness due to aggregation of the above components during drying, and has a release. By adjusting the amount of the silicone-based component on the surface of the layer, even in the production of an ultra-thin ceramic green sheet having a film thickness of 0.2 to 1.0 μm with excellent peelability, the peelability is good and pinholes and the like can be obtained. It is possible to provide a release film for producing a ceramic green sheet, which can reduce defects.

In order to solve the above problems, the present inventors have intensively studied and optimized the drying conditions after coating of the release layer and the content of the silicone-based compound in the release layer, so that the particles were formed on at least one surface. A release film obtained by laminating a release layer directly or via another layer on at least one surface layer A of a polyester film having a surface layer A substantially not containing, wherein the release layer comprises a binder component. And a composition containing a silicone-based release agent is cured, the maximum protrusion height (P) on the surface of the release layer is 50 nm or less, the area average roughness (Sa) is 1.5 nm or less, and The release film for producing a ceramic green sheet, in which the Si element ratio on the outermost surface of the mold layer is 2.0 at% or more and 10.0 at% or less, forms an ultra-thin ceramic green sheet having a thickness of 0.2 to 1.0 μm. When Excellent peelability, in which defects such as pinholes was found to become small. Hereinafter, the present invention will be described in detail.

(Polyester film)
In the present invention, the polyester constituting the polyester film used as the base material is not particularly limited, and a film formed from a polyester generally used as a base material for a release film can be used. It is preferably a crystalline linear saturated polyester comprising an aromatic dibasic acid component and a diol component, for example, polyethylene terephthalate, polyethylene-2,6-naphthalate, polybutylene terephthalate, polytrimethylene terephthalate or a resin thereof. The copolymer containing the above component as a main component is more preferable, and a polyester film formed from polyethylene terephthalate is particularly preferable. In polyethylene terephthalate, the repeating unit of ethylene terephthalate is preferably at least 90 mol%, more preferably at least 95 mol%, and other dicarboxylic acid components and diol components may be copolymerized in small amounts, but from the viewpoint of cost. And those produced only from terephthalic acid and ethylene glycol. Known additives such as an antioxidant, a light stabilizer, an ultraviolet absorber, and a crystallization agent may be added as long as the effects of the film of the present invention are not impaired. The polyester film is preferably a biaxially oriented polyester film for reasons such as high bidirectional elastic modulus.

The intrinsic viscosity of the polyethylene terephthalate film is preferably 0.50 to 0.70 dl / g, more preferably 0.52 to 0.62 dl / g. When the intrinsic viscosity is 0.50 dl / g or more, it is preferable because many breaks do not occur in the stretching step. Conversely, when it is 0.70 dl / g or less, it is preferable because the cutability when cutting into a predetermined product width is good and dimensional defects do not occur. Further, it is preferable that the raw material pellets are sufficiently dried in vacuum.

ポリエステル The method for producing the polyester film in the present invention is not particularly limited, and a method generally used conventionally can be used. For example, it can be obtained by melting the polyester with an extruder, extruding it into a film, cooling it with a rotary cooling drum to obtain an unstretched film, and biaxially stretching the unstretched film. A biaxially stretched film can be obtained by a method of sequentially biaxially stretching a longitudinally or transversely uniaxially stretched film in the transverse or longitudinal direction, or a method of simultaneously biaxially stretching an unstretched film in the longitudinal and transverse directions. I can do it.

において In the present invention, the stretching temperature at the time of stretching the polyester film is preferably equal to or higher than the secondary transition point (Tg) of the polyester. It is preferable to stretch 1 to 8 times, especially 2 to 6 times in each of the longitudinal and transverse directions.

The polyester film preferably has a thickness of 12 to 50 μm, more preferably 15 to 38 μm, and still more preferably 19 to 33 μm. When the thickness of the film is 12 μm or more, there is no possibility of being deformed by heat at the time of film production, a processing step of a release layer, and a molding of a ceramic green sheet or the like, which is preferable. On the other hand, when the thickness of the film is 50 μm or less, the amount of the film to be discarded after use is not extremely increased, which is preferable in reducing the environmental load.

The biaxially oriented polyester film substrate may be a single layer or a multilayer of two or more layers, but preferably has a surface layer A substantially containing no particles on at least one surface. In the case of a laminated polyester film having a multilayer structure of two or more layers, it is preferable to have a surface layer B capable of containing particles and the like on the surface opposite to the surface layer A substantially containing no particles. As for the lamination structure, when the layer on the side where the release layer is applied is the surface layer A, the layer on the opposite side is the surface layer B, and the other core layer is the layer C, the layer configuration in the thickness direction is the release layer / A / B or a laminated structure such as a release layer / A / C / B. Of course, the layer C may have a multilayer structure. Further, the surface layer B may not contain particles. In that case, it is preferable to provide a coat layer containing particles and a binder on the surface layer B in order to impart slipperiness for winding the film into a roll.

において In the polyester film substrate of the present invention, the surface layer A forming the surface on which the release layer is applied preferably does not substantially contain particles. At this time, the average surface roughness (Sa) of the surface layer A is preferably 7 nm or less. When Sa is 7 nm or less, pinholes and the like do not easily occur during molding of the laminated ultra-thin ceramic green sheets, which is preferable. It can be said that the smaller the area surface average roughness (Sa) of the surface layer A is, the more preferable it is, but it may be 0.1 nm or more. Here, when an anchor coat layer or the like described later is provided on the surface layer A, it is preferable that the coat layer contains substantially no particles, and the area average surface roughness (Sa) after the coat layer is laminated falls within the above range. It is preferable to satisfy. In the present invention, "substantially free of particles" means, for example, in the case of inorganic particles, when the inorganic element is quantified by fluorescent X-ray analysis, 50 ppm or less, preferably 10 ppm or less, most preferably the detection limit or less. Content. This is the case where contamination components derived from extraneous foreign substances, dirt attached to raw material resin or lines or equipment in the film manufacturing process are peeled off and mixed into the film without actively adding particles to the film. Because there is.

In the polyester film substrate of the present invention, the surface layer B forming the surface opposite to the surface to which the release layer is applied preferably contains particles from the viewpoint of the slipperiness of the film and the ease with which air can escape. It is preferable to use silica particles and / or calcium carbonate particles. The content of the particles contained in the surface layer B is preferably 5000 to 15000 ppm in total of the particles. At this time, the surface average roughness (Sa) of the film of the surface layer B is preferably in the range of 1 to 40 nm. More preferably, it is in the range of 5 to 35 nm. When the total of the silica particles and / or calcium carbonate particles is 5000 ppm or more and Sa is 1 nm or more, when the film is wound up in a roll, air can be uniformly released, and the rolled shape is good and the flatness is good. This is suitable for producing ultra-thin ceramic green sheets. When the total of silica particles and / or calcium carbonate particles is 15000 ppm or less and Sa is 40 nm or less, the lubricant is less likely to aggregate and coarse projections cannot be formed. And preferred.

粒子 As the particles contained in the surface layer B, inert inorganic particles and / or heat-resistant organic particles other than silica and / or calcium carbonate can be used. From the viewpoint of transparency and cost, it is more preferable to use silica particles and / or calcium carbonate particles, but other inorganic particles that can be used include alumina-silica composite oxide particles, hydroxyapatite particles, and the like. Examples of the heat-resistant organic particles include crosslinked polyacrylic particles, crosslinked polystyrene particles, and benzoguanamine particles. When using silica particles, porous colloidal silica is preferable, and when using calcium carbonate particles, light calcium carbonate surface-treated with a polyacrylic acid-based polymer compound is preferable from the viewpoint of preventing the lubricant from falling off. .

平均 The average particle diameter of the particles added to the surface layer B is preferably 0.1 μm or more and 2.0 μm or less, particularly preferably 0.5 μm or more and 1.0 μm or less. When the average particle diameter of the particles is 0.1 μm or more, the slipperiness of the release film is good, which is preferable. Further, when the average particle size is 2.0 μm or less, there is no possibility that pinholes are generated in the ceramic green sheet due to the coarse particles on the surface of the release layer, which is preferable.

表面 The surface layer B may contain two or more kinds of particles made of different materials. Further, particles of the same kind but having different average particle diameters may be contained.

(4) When the surface layer B does not contain particles, it is preferable that the coat layer containing the particles on the surface layer B has lubricity. The present coating layer is not particularly limited, but is preferably provided as a so-called in-line coating applied during the formation of a polyester film. In the case where the surface layer B does not contain particles and has a coat layer containing particles on the surface layer B, the surface of the coat layer has a surface area for the same reason as the above-mentioned surface average roughness (Sa) of the surface layer B. The average surface roughness (Sa) is preferably in the range of 1 to 40 nm. More preferably, it is in the range of 5 to 35 nm.

表面 From the viewpoint of reducing pinholes, it is preferable not to use a recycled material or the like in the surface layer A, which is the layer on which the release layer is provided, in order to prevent particles such as a lubricant from being mixed.

厚み The thickness ratio of the surface layer A on the side where the release layer is provided is preferably 20% or more and 50% or less of the total thickness of the base film. If it is 20% or more, the influence of the particles contained in the surface layer B and the like is hardly affected from the inside of the film, and it is easy to satisfy the above-mentioned range of the area average surface roughness Sa, which is preferable. When the thickness is 50% or less of the thickness of all the layers of the base material film, the usage ratio of the recycled material in the surface layer B can be increased, and the environmental load is reduced, which is preferable.

から From the viewpoint of economy, the layers other than the surface layer A (the surface layer B or the above-mentioned intermediate layer C) can use 50 to 90% by mass of film waste or recycled materials for PET bottles. Even in this case, it is preferable that the type, amount, particle size, and area average surface roughness (Sa) of the lubricant contained in the surface layer B satisfy the above ranges.

In addition, a film before or after uniaxial stretching in the film forming process is applied to the surface of the surface layer A and / or the surface layer B in order to improve the adhesion of a release layer or the like to be applied later or to prevent electrification. May be provided with a coat layer, or a corona treatment or the like may be performed. When a coat layer is provided on the surface layer A, the coat layer preferably does not substantially contain particles.

(Release layer)
The release layer in the invention is preferably formed by curing a composition containing at least a binder component and a silicone release agent. Other components can be added in addition to the resin or compound as long as the effects of the present invention are not impaired.

(Binder component)
The binder component contained in the composition for forming a release layer of the present invention is not particularly limited, but can be crosslinked to increase the crosslinking density of the release layer and to improve the durability and solvent resistance of the release layer. Preferably, the components are crosslinked. Therefore, it is preferable that a resin having a reactive functional group and a crosslinking agent are reacted with the binder component. In addition, it is also preferable that either the reactive functional group or the crosslinking agent is used to form a self-crosslinking. However, the present invention does not exclude an embodiment in which the binder component comprises only a resin having a reactive functional group or a crosslinking agent.

樹脂 The resin having a reactive functional group is not particularly limited, but polyester resins, poly (meth) acrylic resins, polyurethane resins, polyolefin resins and the like can be suitably used. It is preferable that these resins have at least one kind selected from a carboxyl group, a hydroxyl group, an epoxy, an amino group and the like as a reactive functional group.

樹脂 The resin having a reactive functional group preferably has a long-chain alkyl group and / or a silicone skeleton as a part of the resin skeleton. By having a part of the resin skeleton having a low surface free energy such as a long chain alkyl group and / or a silicone skeleton, the compatibility between the silicone-based release agent and the binder component described later is increased, and aggregation during drying is performed. Is less likely to occur and the smoothness is improved.

Specific examples of the reactive functional group-containing resin having a long-chain alkyl group in the resin skeleton include an alkyd resin or a (meth) acryl resin having a long-chain alkyl group in a side chain. As the long-chain alkyl group to be used, a linear alkyl group having 6 to 20 carbon atoms is preferable. Having the above-described carbon number is preferable because the surface free energy of the obtained resin can be reduced and the compatibility with the silicone-based release agent is improved.

In the case of an alkyd resin having a long-chain alkyl group in the side chain, an acid having a long-chain alkyl group (for example, octylic acid or stearyl acid) is mixed with a polybasic acid such as phthalic acid to form a polyhydric alcohol component ( Pentaerythritol and diethylene glycol), and can be obtained by a dehydration condensation reaction.

(4) The (meth) acrylic resin having a long-chain alkyl group in the side chain is preferably obtained by copolymerizing two or more (meth) acrylic monomers. The monomer to be copolymerized preferably contains a monomer having a long-chain alkyl group (for example, lauryl (meth) acrylate, stearyl (meth) acrylate, isodecyl (meth) acrylate, etc.), and a hydroxy group as a reactive functional group site. (E.g., hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, etc.). In addition to the above, other known monomers such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, hexanediol dimethacrylate, and butanediol diacrylate may be included in order to impart Tg adjustment, crosslinkability, and reactivity of the obtained polymer. .

含有 The content of the monomer having a long-chain alkyl group constituting the obtained acrylic resin is preferably 1 mol% or more and 50 mol% or less based on all the monomers constituting the acrylic resin. When the content is 1 mol% or more, the effect of lowering the surface free energy is obtained. When the content is 50 mol% or less, the monomer having a reactive functional group becomes relatively high, so that the crosslinking density of the resin becomes high.

Specific examples of the reactive functional group-containing resin having a silicone skeleton in the resin skeleton include an alkyd resin or an acrylic resin having a polydimethylsiloxane skeleton in a side chain. Specific examples of commercially available products include Cymac (registered trademark) US350, US352 (manufactured by Toagosei Co., Ltd., reactive functional group: carboxyl group) and Cymac (registered trademark) US270 (manufactured by Toagosei Co., Ltd., reactive functional group: hydroxyl group) )and so on.

(Crosslinking agent)
It is also preferable that the binder component contains a crosslinking agent. The crosslinking agent is not particularly limited, but a melamine-based, isocyanate-based, carbodiimide-based, oxazoline-based, or epoxy-based cross-linking agent may be used, and one type or two or more types may be used in combination. . Particularly preferably, a cross-linking agent that reacts with the reactive functional group introduced into the binder component is preferable.

As the crosslinking agent used in the present invention, a melamine-based compound is preferable from the viewpoint of reactivity. The use of a melamine-based compound is preferable because a thin film having a coating amount of 0.2 g / m ² or less after curing of the release layer can be quickly cured and the crosslink density is increased.

As the melamine-based compound used in the present invention, a general compound can be used and is not particularly limited. The melamine-based compound is obtained by condensing melamine and formaldehyde, and has a triazine ring and a methylol group and / or an alkoxymethyl group in one molecule. It is preferable to have one or more. Specifically, a compound obtained by subjecting a methylol melamine derivative obtained by condensing melamine and formaldehyde to a lower alcohol, such as methyl alcohol, ethyl alcohol, isopropyl alcohol, butyl alcohol, or the like, to undergo a dehydration condensation reaction and to be etherified is preferred. Examples of the methylolated melamine derivative include monomethylol melamine, dimethylol melamine, trimethylol melamine, tetramethylol melamine, pentamethylol melamine, and hexamethylol melamine. One type or two or more types may be used.

As the melamine-based compound, hexamethylolmelamine or hexamethoxymethylolmelamine having many crosslinking points in one molecule is preferably used because the crosslinking density of the binder component can be increased. When an ether compound obtained by a dehydration condensation reaction using an alcohol with a methylol melamine derivative is used, hexamethoxymethyl methylol melamine obtained by dehydration condensation with methyl alcohol is particularly preferable from the viewpoint of reactivity.

The amount of the crosslinking agent contained in the binder component in the present invention is preferably 15% by mass or more, more preferably 30% by mass or more, even more preferably 50% by mass, based on the resin having a reactive functional group. It is. When the crosslinking agent can form a resin film by self-condensation, the binder component may be constituted only by the crosslinking agent. When the crosslinking agent is contained in an amount of 15% by mass or more, the crosslinking density of the release layer can be increased, and the solvent resistance and the elastic modulus can be improved.

(catalyst)
The composition for forming a release layer according to the present invention may contain a catalyst for curing the crosslinking agent. When a melamine-based compound is used, an acid catalyst is preferably used, and although not particularly limited, carboxylic acid-based, metal salt-based, phosphate ester-based, and sulfonic acid-based compounds can be suitably used. Further, a block type catalyst in which an acid site is blocked can also be used. In particular, paratoluenesulfonic acid can be preferably used from the viewpoint of reactivity. When an isocyanate-based compound is used, a general one can be used, and organotin, an amine compound, a trialkylphosphine compound, and the like can be suitably used.

The content of the catalyst is preferably 0.1 to 40% by mass based on the crosslinking agent contained in the composition for forming a release layer. More preferably, it is 0.5 to 30% by mass. More preferably, it is 0.5 to 20% by mass. When the content is 0.1% by mass or more, the curing reaction easily proceeds, which is preferable. On the other hand, when the content is 40% by mass or less, there is no possibility that the acid catalyst is transferred to the ceramic green sheet to be molded, and there is no possibility that the acid catalyst has an adverse effect.

(Silicone release agent)
The silicone-based release agent used in the release layer in the present invention is a compound having a silicone structure in the molecule, and is not particularly limited as long as the effects of the present invention can be obtained. Can be used. Among polyorganosiloxanes, polydimethylsiloxane (abbreviation: PDMS) can be suitably used, and those having a functional group in a part of polydimethylsiloxane are also preferable. Having a functional group is preferable because an intermolecular interaction such as a hydrogen bond with a binder resin is easily generated and migration to a ceramic green sheet becomes difficult.

The functional group introduced into the polydimethylsiloxane is not particularly limited, but may be a reactive functional group or a non-reactive functional group. The functional group may be introduced at one terminal of the polydimethylsiloxane, and may be at both terminals or a side chain. In addition, one or a plurality of positions may be introduced.

(4) Examples of the reactive functional group to be introduced into polydimethylsiloxane include an amino group, an epoxy group, a hydroxyl group, a mercapto group, a carboxyl group, a methacryl group, and an acryl group. As the non-reactive functional group, a polyether group, an aralkyl group, a fluoroalkyl group, a long-chain alkyl group, an ester group, an amide group, a phenyl group and the like can be used. Although not particularly limited by theory, those having an epoxy group, a carboxyl group, a polyether group, a methacryl group, an acryl group, and an ester group are preferable.

官能 It is more preferable that the functional group introduced into the polydimethylsiloxane does not react with the binder component. For example, polydimethylsiloxane modified with a hydroxyl group that reacts with melamine resin reacts with melamine in the drying process, so it is difficult to orient on the surface of the release layer, and the Si element ratio on the surface of the release layer decreases, and the release property decreases. In some cases, expression is difficult. Therefore, it is necessary to increase the amount of addition in order to have sufficient releasability, but in that case, the elastic modulus of the release layer may be reduced and the release layer may be easily deformed.

As the functional group to be introduced into the polydimethylsiloxane, the functional group which does not react with the binder resin for the reasons described above, is easily oriented on the surface of the release layer, and has a low migration property to the ceramic green sheet, particularly a polyether group, Ester groups are preferred, and polyether groups are particularly preferred. A carboxyl group is an example of a functional group that has a relatively large Si element ratio on the surface of the release layer even when it reacts with the binder resin.

シリコーン The silicone release agent used in the present invention preferably has a molecular weight of 40,000 or less. More preferably, it is 30,000 or less. When the molecular weight is 40,000 or less, the silicone-based release agent easily segregates on the surface of the release layer, and has good releasability, which is preferable.

The content of the silicone-based release agent-derived component contained in the release layer after curing in the present invention is preferably 1 mg / m ² or more and 15 mg / m ² or less. More preferably, it is 1 mg / m ² or more and 10 mg / m ² or less. When the content is 1 mg / m ² or more, the silicone component can be sufficiently precipitated on the outermost layer of the release layer, and the releasability of the ceramic green sheet is stabilized, which is preferable. When the amount is 15 mg / m ² or less, the silicone component having a relatively low elastic modulus is small in the release layer, so that the elastic modulus of the release layer does not become too low and the releasability of the ceramic sheet is stabilized, which is preferable. Here, the silicone-based release agent may be present in the same structure without changing its chemical structure even in the release layer after curing, or by causing a chemical reaction with a binder component or the like. In some cases, the chemical structure is changed. Therefore, the mass of the substance present per unit area of the release layer after curing, which is derived from the silicone release agent in the composition before curing, is described as the content of the silicone release agent-derived component. . The content of the silicone-based release agent-derived component is determined based on the proportion (% by mass) of the silicone-based release agent in the solid content of the coating liquid containing the composition and the applied amount of the cured release layer solid (g / g). m ² ).

離 The release layer in the present invention may contain particles having a particle size of 1 μm or less, but it is preferable not to contain particles or the like that form projections from the viewpoint of suppressing pinholes in the ceramic green sheet.

密着 An additive such as an adhesion improver or an antistatic agent may be added to the release layer in the present invention as long as the effect of the present invention is not impaired. Further, in order to improve the adhesion to the base material, it is also preferable to perform a pretreatment such as an anchor coat, a corona treatment, a plasma treatment, or an atmospheric pressure plasma treatment on the polyester film surface before providing the release coating layer.

In the present invention, the coating amount of the release layer after curing is not particularly limited, but is preferably 1.0 g / m ² or less. It is more preferably 0.01 to 0.5 g / m ² , still more preferably 0.02 to 0.20 g / m ² , and more preferably 0.02 to 0.09 g / m ² . It is preferable that the coating amount of the release layer is 0.01 g / m ² or more, since the release performance can be easily obtained. When it is 0.2 g / m ² or less, the curing time of the release layer can be shortened, so that the flatness of the release film can be maintained and the thickness unevenness of the ceramic green sheet can be suppressed, which is preferable. Further, when the content is 0.2 g / m ² or less, the curl of the obtained film is reduced, so that the molding accuracy at the time of molding the ceramic green sheet is preferably improved.

Surface free energy of the release layer surface of the release film of the present invention is preferably 18 mJ / ^{m 2} or more 35 mJ / ^{m 2} or less. More preferably, 20 mJ / ^{m 2} or more 30 mJ / ^{m 2} or less, further preferably 21 mJ / ^{m 2} or more 28 mJ / ^{m 2} or less. When it is at least 18 mJ / m ^2, repelling is less likely to occur when the ceramic slurry is applied, which is preferable. In addition, when it is 35 mJ / m ² or less, there is no possibility that the releasability of the ceramic green sheet is reduced, which is preferable. By setting the content within the above range, a release film having no repelling during coating and excellent in releasability can be provided.

The release film of the present invention preferably has a peel force of 0.5 mN / mm ² or more and 3 mN / mm ² or less when peeling the ceramic green sheet. More preferably, it is 0.8 mN / mm ² or more and 2.5 mN / mm ² or less. More preferably, 1.0 mN / mm ² or more and 1.8mN / mm ² or less. When the peeling force is 0.5 mN / mm ² or more, the peeling force is not too light, and there is no possibility that the ceramic green sheet will be lifted during transportation. When the peeling force is 3 mN / mm ² or less, the ceramic green sheet is not likely to be damaged at the time of peeling, which is preferable.

離 The release film of the present invention preferably has less curl. Specifically, the curl after heating at 100 ° C. for 15 minutes without applying tension to the film is preferably 2 mm or less, more preferably 1 mm or less. Of course, it is also preferable that no curling occurs. When the thickness is set to 2 mm or less, the curling is small when the ceramic green sheet is formed and the electrode is printed, so that the printing accuracy can be improved.

It is preferable that the silicone-based release agent-derived component contained in the release layer is sufficiently precipitated on the surface of the release layer of the release film of the present invention. The ratio of the Si element on the surface of the release layer can be used as an index indicating the amount of the component derived from the silicone release agent. The Si element ratio on the release layer surface can be evaluated by ESCA, which can measure only the surface of the release layer. Note that the Si element ratio in the present invention is a ratio (at%) of Si in five elements of C, S, Si, O, and N as in the following equation.
Si element ratio (at%) = {Si / (C + O + N + S + Si)} × 100 formula

ＳｉThe Si element ratio on the outermost surface of the release layer of the release film of the present invention is preferably 2.0 at% or more. It is more preferably at least 2.5 at%, more preferably at least 3.0 at%, still more preferably at least 3.5 at%. If the content is 2.0 at% or more, the surface of the release layer can be sufficiently covered with the silicone-based release agent, and the release force is stable when the thin ceramic green sheet is released. The upper limit of the Si element ratio is preferably 10 at% or less, more preferably 9 at% or less, and still more preferably 8 at% or less. When the content is 10 at% or less, the elastic modulus of the surface of the release layer is not reduced and the peeling is stable, which is preferable.

In order to achieve the Si element ratio on the release layer outermost surface of the release film of the present invention, the content of the silicone-based release agent-derived component contained in the release layer after curing described above and the release described later It is preferable to optimize the passage time of the initial drying step after coating the layer.

The surface of the release layer of the release film of the present invention is desirably flat so as not to cause defects in the ceramic green sheet applied and molded thereon, and the average surface roughness (Sa) of the region is 1.5 nm. Is preferably 1.2 nm or less, more preferably 1.0 nm or less. Further, the maximum projection height (P) of the release layer surface is preferably 50 nm or less, more preferably 40 nm or less, and still more preferably 30 nm or less. When the area surface average roughness (Sa) is 1.5 nm or less and the maximum projection height (P) is 50 nm or less, defects such as pinholes do not occur during formation of the ceramic green sheet, and the yield is good, which is preferable. It can be said that the smaller the area surface average roughness (Sa) is, the better. However, it may be 0.1 nm or more, or 0.3 nm or more. It can be said that the maximum protrusion height (P) is preferably as small as possible, but it may be 1 nm or more, or 3 nm or more.

Since the release film of the present invention uses a highly planarized base film, the coating amount of the release layer is preferably 0.2 g / m ² or less, more preferably 0.09 g / m 2. Even if it is thinner than ^{2, the} release layer surface can be smoothed, so the amount of solvent and resin used can be reduced, and it is environmentally friendly and inexpensive release film for forming ultra-thin ceramic green sheets. Can be created.

In order that the maximum projection height (P) of the release layer surface of the release film of the present invention is 50 nm or less and the area average roughness (Sa) is 1.5 nm or less, a coating liquid for the release layer is applied. It is preferable to suppress aggregation of the silicone-based release agent and the binder component before drying. Therefore, as described in the below-described production method, the target ultra-high smooth release layer surface can be obtained by performing the time from application to drying under constant conditions.

(Production method of release film)
The method for producing the release film of the present invention is not particularly limited, but a coating solution obtained by dissolving or dispersing at least a binder component and a silicone-based release agent in a solvent is laminated on at least one surface of the base polyester film by coating or the like. It is preferable to use a method in which a release layer is laminated through an application step of applying, an initial drying step of mainly removing a solvent and the like after the application, and a heat curing step of mainly curing a binder resin and the like. The surface of the polyester film on the side where the release layer is provided is preferably a surface layer A substantially containing no particles, and another coat layer exists between the surface layer A and the release layer. No problem.

(Coating process)
The solvent for dissolving or dispersing the binder resin and the silicone-based release agent is not particularly limited, but it is preferable to use an organic solvent. Use of an organic solvent is preferable because the surface tension of the coating liquid can be reduced, so that repelling or the like does not easily occur after coating, and the smoothness of the surface of the release layer can be kept high.

有機 The organic solvent used in the method for producing a release film of the present invention is not particularly limited, and any known organic solvent can be used. Examples of the solvent include aromatic hydrocarbons such as benzene, toluene and xylene, fatty acid hydrocarbons such as cyclohexane, n-hexane and n-heptane, halogenated hydrocarbons such as perchloroethylene, ethyl acetate, methyl ethyl ketone and methyl. Isobutyl ketone and the like. Taking into account the applicability when applying to the surface of the substrate film, a mixed solvent of toluene and methyl ethyl ketone is practically preferable, although not limited.

において In the present invention, the coating liquid used for coating for forming the release layer is not particularly limited, but preferably contains two or more kinds of organic solvents having different boiling points. It is preferable that at least one organic solvent has a boiling point of 100 ° C. or higher. By adding a solvent having a boiling point of 100 ° C. or more, bumping during drying can be prevented, the coating film can be leveled, and the smoothness of the dried coating film surface can be improved. It is preferable to add about 10 to 50% by mass of the total amount of the coating solution. Examples of the solvent having a boiling point of 100 ° C. or higher include toluene, xylene, heoctane, cyclohexanone, methyl isobutyl ketone, and n-propyl acetate.

において In the present invention, the surface tension (20 ° C.) of the coating liquid when applying the coating liquid for forming a release layer is not particularly limited, but is preferably 30 mN / m or less. By setting the surface tension as described above, the wettability after coating is improved, and the unevenness of the coating film surface after drying can be reduced. In order to lower the surface tension of the coating liquid, it is preferable to use an organic solvent having a low surface tension as the organic solvent forming the coating liquid. The surface tension (at 20 ° C.) of at least one organic solvent is preferably 26 mN / m or less, more preferably 23 mN / m or less. It is preferable to include an organic solvent having a surface tension (20 ° C.) of 26 mN / m or less because appearance defects such as repelling during coating can be reduced. It is preferable to add 20% by mass or more to the entire coating liquid.

(4) The solid content concentration of the release agent contained in the coating liquid is preferably from 0.1% by mass to 10% by mass, more preferably from 0.2% by mass to 8% by mass. When the solid content concentration is 0.1% by mass or more, drying after application is fast, and aggregation of components in the release agent hardly occurs, which is preferable. On the other hand, when the solid content concentration is 10% by mass or less, the viscosity of the coating liquid is low and the leveling property is good, so that the flatness after coating can be improved, which is preferable. The viscosity of the coating liquid is preferably from 1 mPa · s to 100 mPa · s from the viewpoint of coating appearance, and more preferably from 2 mPa · s to 10 mPa · s. It is preferable to adjust the solid content concentration, the organic solvent and the like so as to fall within this range.

において In the present invention, the coating liquid for forming a release layer is preferably filtered before coating. The filtration method is not particularly limited, and a known method can be used. However, it is preferable to use a surface type, depth type or adsorption type cartridge filter. The use of a cartridge-type filter is preferable because the coating liquid can be used when the coating liquid is continuously fed from the tank to the coating section, so that productivity can be efficiently filtered. It is preferable to use a filter capable of removing 99% or more of a filter having a size of 1 μm, more preferably a filter capable of filtering 99% or more of a filter having a size of 0.5 μm. By using the above-mentioned filtration accuracy, foreign matter mixed in the release agent can be removed, and foreign matter attached to the release film of the ceramic green sheet molding release film of the present invention can be significantly reduced. it can. Therefore, the defects of the ceramic green sheet molded using the release film of the present invention are reduced, and the defective rate of the ceramic capacitor can be reduced.

As the coating method of the coating liquid, any known coating method can be applied, for example, a roll coating method such as a gravure coating method or a reverse coating method, a bar coating method such as a wire bar, a die coating method, a spray coating method, and an air knife. A conventionally known method such as a coating method can be used.

The coating liquid film thickness (wet amount) at the time of coating is preferably 1 g / m ² or more and 10 g / m ² or less. When the thickness is more than 1 g / m ² , the coating is stable, and defects such as repelling and streaks are less likely to appear, which is preferable. Further, when the content is 10 g / m ² or less, it is preferable that the components contained in the release layer be dried quickly and hardly aggregate.

(Drying process)
Examples of the method of applying the coating liquid on the base film and drying the coating liquid include known hot-air drying and drying by heating with an infrared heater. Hot-air drying with a high drying speed is preferred. The drying furnace can be divided into a constant-rate drying step (hereinafter, referred to as an initial drying step) at an early stage of drying, and a step in which reduced-rate drying and curing of the resin proceed (hereinafter, referred to as a heat curing step). The initial drying step and the heat-curing step may be continuous or discontinuous, but the continuous step is preferable because the productivity is good. It is preferable that the respective steps are distinguished by dividing the drying furnace zone. The number of zones in each step may be any number as long as it is one or more.

において In the method for producing a release film of the present invention, it is preferable that the film is placed in a drying oven within 1.5 seconds after application, more preferably within 1.0 second, and even more preferably within 0.8 seconds. Since the components contained in the release layer can be dried before agglomeration occurs by placing them in a drying oven and drying within 1.5 seconds after application, it is possible to prevent the smoothness of the surface of the release layer from being deteriorated due to aggregation. Is preferred because It is preferable that the time from application to the drying oven is short, and there is no particular lower limit, but it may be 0.05 seconds or longer, or 0.1 seconds or longer.

The initial drying step is not particularly limited, and a known drying furnace can be used. Regarding the drying furnace method, either the roll support method or the floating method may be used, but the roll support method has a wider range where the air volume during drying can be adjusted, so the air volume etc. is adjusted according to the type of release layer It is preferable because it is possible.

温度 The temperature of the initial drying step is preferably from 60 ° C to 140 ° C, more preferably from 70 ° C to 130 ° C, even more preferably from 80 ° C to 120 ° C. A temperature of 60 ° C. or more and 140 ° C. or less is preferable because the amount of the organic solvent contained in the release layer after coating can be effectively dried without poor planarity due to heat.

The time required to pass through the initial drying step is preferably from 1.0 to 3.0 seconds, more preferably from 1.0 to 2.5 seconds, and more preferably from 1.2 to 2.5 seconds. Seconds or less are more preferred. The time is preferably at least 1.0 second because the organic solvent contained in the release layer after application can be sufficiently dried. Further, it is preferable to set the release time to 1.0 second or longer because the component derived from the silicone release agent contained in the release layer can be effectively deposited on the surface of the release layer. Further, when the time is 3.0 seconds or less, aggregation of the components in the release layer hardly occurs, which is preferable. By adjusting the solid content concentration of the coating liquid, the type of organic solvent, and the like so that the coating liquid can be dried in the above-described time, deterioration in smoothness due to aggregation can be suppressed even when a coating liquid that easily aggregates is used.

(5) The amount of the organic solvent contained in the release layer after passing through the initial drying step is preferably 5% by mass or less, more preferably 2% by mass or less. When the amount of the organic solvent is 5% by mass or less, deterioration in appearance due to bumping or the like can be prevented even when heated in the heating step, which is preferable. The amount of the organic solvent in the release layer can be measured by gas chromatography or thermogravimetric analysis after sampling the film after the initial drying step, but it can be estimated by using a drying simulation. It is preferable to obtain the value from simulation because measurement can be performed without stopping the process. The simulation is not particularly limited, but known simulation software can be used.

(Heat curing process)
The release film of the present invention preferably undergoes a heat curing step after the initial drying step. The heat curing step is not particularly limited, and a known drying furnace can be used. Regarding the drying furnace system, either a roll supporting system or a floating system may be used. The heat curing step may be a step that is continuous with the initial drying step or a step that is discontinuous, but is preferably a step that is continuous from the viewpoint of productivity.

温度 The temperature of the heat curing step is preferably 80 ° C or more and 180 ° C or less, more preferably 90 ° C or more and 160 ° C or less, and most preferably 90 ° C or more and 140 ° C or less. When the temperature is 180 ° C. or lower, the flatness of the film is maintained, and the possibility of causing thickness unevenness of the ceramic green sheet is small, which is preferable. When the temperature is 140 ° C. or lower, processing can be performed without impairing the flatness of the film, and the possibility of causing unevenness in the thickness of the ceramic green sheet is further reduced. When the temperature is 80 ° C. or higher, the thermosetting resin is preferable because the curing proceeds sufficiently.

時間 The time of passing through the heat curing step is preferably 2 seconds or more and 30 seconds or less, more preferably 2 seconds or more and 20 seconds or less. If the passage time is 2 seconds or longer, the curing of the thermosetting resin proceeds, which is preferable. Further, it is preferable that the time is 30 seconds or less, since the flatness of the film due to heat does not decrease.

(4) At the end of the heat curing step, it is preferable that the hot air temperature be equal to or lower than the glass transition temperature of the base film and the actual temperature of the base film in a flat state be equal to or lower than the glass transition temperature. If the actual temperature of the base film leaves the drying oven at or above the glass transition temperature, slippage will be poor when it comes into contact with the roll surface, and not only will scratches and the like occur, but curl etc. may occur. is there.

離 The release film of the present invention is preferably wound up in a roll after passing through the heat curing step. After passing through the heat curing step, the time required for winding into a roll is preferably 2 seconds or more, more preferably 3 seconds or more. When the time is at least 2 seconds, the release film, the temperature of which has been raised in the heat curing step, is cooled and wound up on a roll.

In the release film of the present invention and the method for producing the same, various treatments may be carried out after the heat-curing step and before winding into a roll, aging treatment, charge removal treatment, corona treatment, plasma treatment, ultraviolet irradiation treatment. And an electron beam irradiation treatment.

(Ceramic green sheet and ceramic capacitor)
Generally, a multilayer ceramic capacitor has a rectangular parallelepiped ceramic body. Inside the ceramic body, first internal electrodes and second internal electrodes are provided alternately along the thickness direction. The first internal electrode is exposed on a first end face of the ceramic body. A first external electrode is provided on the first end surface. The first internal electrode is electrically connected to a first external electrode at a first end face. The second internal electrode is exposed on the second end face of the ceramic body. A second external electrode is provided on the second end surface. The second internal electrode is electrically connected to a second external electrode at a second end face.

型 The release film for producing a ceramic green sheet of the present invention is used for producing such a multilayer ceramic capacitor. For example, it is manufactured as follows. First, using the release film of the present invention as a carrier film, a ceramic slurry for forming a ceramic body is applied and dried. A conductive layer for forming the first or second internal electrode is printed on the applied and dried ceramic green sheet. The ceramic green sheet, the ceramic green sheet on which the conductive layer for forming the first internal electrode is printed, and the ceramic green sheet on which the conductive layer for forming the second internal electrode is printed are appropriately laminated and pressed. Thereby, a mother laminate is obtained. The mother laminate is divided into a plurality of pieces to produce a raw ceramic body. The ceramic body is obtained by firing the raw ceramic body. After that, by forming the first and second external electrodes, the multilayer ceramic capacitor can be completed.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples. The characteristic values used in the present invention were evaluated using the following methods.

(Region surface average roughness (Sa), maximum protrusion height (P))
It is a value measured under the following conditions using a non-contact surface profile measuring system (VertScan R550H-M100, manufactured by Ryoka Systems Inc.). The average surface roughness of the area (Sa) was an average value of five measurements, and the maximum protrusion height (P) was measured seven times, and the five maximum values excluding the maximum value and the minimum value were used.
(Measurement condition)
・ Measurement mode: WAVE mode ・ Objective: 10 × ・ 0.5 × Tube lens ・ Measurement area 936 μm × 702 μm
(Analysis conditions)
・ Surface correction: 4th order correction ・ Interpolation processing: Complete interpolation ・ Filter processing: Gaussian cut-off value 50μm

(Amount of release layer applied)
The coating amount of the release layer after curing of the release film of the present invention was measured by a gravimetric method. The release film was sampled to a size of 15 cm × 15 cm, and after neutralization using a static eliminator, the weight was measured using a precision balance (AUW120D manufactured by Shimadzu Corporation). The measured release layer of the release film was wiped off using methyl ethyl ketone, dried at 80 ° C. for 1 minute with a hot-air drier, and the mass was measured again using a precision balance. The release layer coating amount (g / m ² ) was calculated by dividing the difference in the film weight after wiping from the film weight before wiping the release layer by the film area (15 cm × 15 cm). The measurement was performed five times using films sampled from different locations, and an average value of three times excluding the maximum value and the minimum value was used.

(Ratio of Si element on the outermost surface of the release layer)
The Si element ratio at the outermost surface of the release layer of the release film of the present invention was measured by ESCA. The device is K-Alpha
⁺ (Manufactured by Thermo Fisher Scientific) was used. Details of the measurement conditions are shown below. Using this apparatus, a narrow scan was performed for five elements of C, O, N, S, and Si on the surface of the release layer, and the Si element ratio (at%) was calculated from the following equation. (In the present invention, the Si element ratio is the ratio (at%) of Si in the five elements of C, O, N, S, and Si.)
Si element ratio (at%) = {Si / (C + O + N + S + Si)} × 100 Expression In the analysis, the background was removed by the shirley method. The surface Si element ratio was an average value of the measurement results at three or more locations.

・ Measurement conditions Excitation X-ray: Monochrome Al Ka-ray X-ray output: 12 kV, 6 mA
Photoelectron escape angle: 90 °
Spot size: 400 mm f (approx.)
Pass energy: 50eV
Step: 0.1eV

(Surface free energy)
Using a contact angle meter (manufactured by Kyowa Interface Science Co., Ltd .: fully automatic contact angle meter DM-701) under the conditions of 25 ° C. and 50% RH, water (1.8 μL of droplet amount) was applied to the release surface of the release film , A liquid drop of diiodomethane (suitable amount of liquid 0.9 μL) and ethylene glycol (suitable amount of liquid 0.9 μL) were prepared, and the contact angles were measured. As the contact angle, a contact angle 10 seconds after each liquid was dropped onto the release film was employed. The contact angle data of water, diiodomethane, and ethylene glycol obtained by the above method were calculated from the "Kitasaki-Hata" theory to determine the dispersion component γsd, polar component γsp, and hydrogen bond component γsh of the surface free energy of the release film, The sum of the components was defined as surface free energy γs. This calculation was performed using calculation software in the contact angle meter software (FAMAS).

(Surface tension of coating liquid)
The surface tension of the coating liquid was measured by a Wilhelmy method using a platinum plate at 20 ° C. using a surface tensiometer (manufactured by Kyowa Interface Science Co., Ltd .: DY-500 high-performance surface tensiometer). The measurement was performed three times and the average value was adopted.

(Viscosity of coating liquid)
The viscosity of the coating liquid was measured at 20 ° C. using a rotary viscometer (TVB-15M, manufactured by Toki Sangyo Co., Ltd.). When measuring a low viscosity liquid of 10 mPa · s or less, the measurement was performed using an optional low viscosity adapter. The measurement was performed three times, and the average value was adopted.

(Evaluation of coatability of ceramic slurry)
The composition composed of the following materials was stirred and mixed, and dispersed with zirconia beads having a diameter of 0.5 mm using a bead mill for 60 minutes to obtain a ceramic slurry.
76.3 parts by mass of toluene 76.3 parts by mass of ethanol 75.0 parts by mass of barium titanate (HPBT-1 manufactured by Fuji Titanium Co., Ltd.) 35.0 parts by mass 3.5 parts by mass of polyvinyl butyral 3.5 parts by mass (ESREC® BM-S manufactured by Sekisui Chemical Co., Ltd.)
1.8 parts by mass of DOP (dioctyl phthalate) Then, the release surface of the obtained release film sample is applied using an applicator so that the slurry after drying is 1 μm, and dried at 90 ° C. for 1 minute. The coatability was evaluated based on the following criteria. ：: The entire surface was coated without repelling.
Δ: Although some repelling was observed at the coated end, the coating was completed on almost the entire surface.
×: Many cissings were not applied.

(Evaluation of pinholes on ceramic green sheets)
A ceramic green sheet having a thickness of 1 μm was formed on the release surface of the release film in the same manner as in the evaluation of the coatability of the ceramic slurry.
Subsequently, the slurry after drying was applied to the release surface of the obtained release film sample using an applicator so as to have a thickness of 1 μm, dried at 90 ° C. for 1 minute, the release film was peeled off, and the ceramic green sheet was removed. Obtained.
In the center region of the obtained ceramic green sheet in the film width direction, light is applied from the opposite surface of the ceramic slurry application surface in a range of 25 cm ² , and the state of occurrence of pinholes through which light is visible is observed. It was visually determined.
：: No pinholes are generated △: Almost no pinholes are generated X: Many pinholes are generated

(Evaluation of peelability of ceramic green sheet)
The composition composed of the following materials was stirred and mixed, and dispersed with zirconia beads having a diameter of 0.5 mm using a bead mill for 60 minutes to obtain a ceramic slurry.
38.3 parts by mass of toluene 38.3 parts by mass of ethanol 34.8 parts by mass of barium titanate (HPBT-1 manufactured by Fuji Titanium Co., Ltd.) 64.8 parts by mass of polyvinyl butyral 6.5 parts by mass (ESREC (registered trademark) BM-S manufactured by Sekisui Chemical Co., Ltd.)
3.3 parts by mass of DOP (dioctyl phthalate) Then, the slurry after drying is applied to the release surface of the obtained release film sample using an applicator so as to have a thickness of 10 μm, dried at 90 ° C. for 1 minute, and dried. A green sheet was formed on a release film. The obtained release film with ceramic green sheet was subjected to static elimination using a static eliminator (manufactured by Keyence Corporation, SJ-F020), and then peeled at a peel angle of 90 °, a peel angle of 90 ° and a peel speed of 10 m / min. The stress applied during peeling was measured and used as the peeling force.

(Evaluation of peeling stability of ceramic green sheet)
The peelability was evaluated 10 times in the same manner as the peelability evaluation of the ceramic green sheet described above. The dispersion of the peeling force 10 times was evaluated based on the following criteria, and the evaluation was made as the peeling stability.
：: The difference between the maximum value and the minimum value measured 10 times was smaller than 0.5 mN / mm ² .
Δ: The difference between the maximum value and the minimum value measured 10 times was 0.5 mN / mm ² or more and less than 1.0 N / mm ² .
×: The difference between the maximum value and the minimum value measured 10 times was smaller than 1.0 mN / mm ² .

(Curl evaluation of release film)
The release film sample was cut into a size of 10 cm × 10 cm, and heat-treated at 100 ° C. for 15 minutes in a hot-air oven so that tension was not applied to the release film. Then, after taking out from the oven and cooling to room temperature, a release film sample was placed on a glass plate so that the release surface faced upward, and the height of the portion floating from the glass plate was measured. At this time, the height of the portion floating the largest from the glass plate was taken as the measured value. The curl properties were evaluated according to the following criteria.
：: The curl is 1 mm or less, and almost no curl.
Δ: The curl was larger than 1 mm and 2 mm or less, and a slight curl was observed.
X: The curl was larger than 2 mm.

(Preparation of polyethylene terephthalate pellet (PET (I)))
As the esterification reactor, a continuous esterification reactor consisting of a three-stage complete mixing tank having a stirrer, a decomposer, a raw material inlet, and a product outlet was used. TPA (terephthalic acid) was set at 2 tons / hour, EG (ethylene glycol) was set at 2 moles with respect to 1 mole of TPA, antimony trioxide was used in such an amount that Sb atoms became 160 ppm with respect to generated PET, and these slurries were esterified. The mixture was continuously supplied to the first esterification reactor of the conversion reaction apparatus, and reacted at 255 ° C. at ordinary pressure for 4 hours on average. Next, the reaction product in the first esterification reactor is continuously taken out of the system and supplied to the second esterification reactor, and is distilled from the first esterification reactor into the second esterification reactor. EG solution containing magnesium acetate tetrahydrate in an amount such that Mg atoms become 65 ppm with respect to the generated PET, and 40 ppm with P atoms with respect to the generated PET. An EG solution containing the following amount of TMPA (trimethyl phosphate) was added and reacted at 260 ° C. for 1 hour at an average residence time at normal pressure. Next, the reaction product of the second esterification reactor is continuously taken out of the system and supplied to the third esterification reactor, and 39 MPa (400 kg / cm ² ) using a high-pressure disperser (manufactured by Nippon Seiki Co., Ltd.). 0.2% by mass of porous colloidal silica having an average particle size of 0.9 μm subjected to dispersion treatment with an average number of treatments of 5 passes at a pressure of 0.2%, and 1% by mass of an ammonium salt of polyacrylic acid per calcium carbonate adhered thereto While adding 0.4% by mass of synthetic calcium carbonate having a diameter of 0.6 μm as EG slurries of 10% each, the mixture was reacted at 260 ° C. and an average residence time of 0.5 hour at normal pressure. The esterification reaction product generated in the third esterification reaction vessel was continuously supplied to a three-stage continuous polycondensation reaction apparatus to perform polycondensation, and sintered a stainless steel fiber having a 95% cut diameter of 20 μm. After filtration with a filter, ultrafiltration was performed and the mixture was extruded into water. After cooling, the mixture was cut into chips to obtain a PET chip having an intrinsic viscosity of 0.60 dl / g (hereinafter abbreviated as PET (I)). . The lubricant content in the PET chip was 0.6% by mass.

(Preparation of polyethylene terephthalate pellet (PET (II)))
On the other hand, in the production of the above-mentioned PET chip, a PET chip having an intrinsic viscosity of 0.62 dl / g containing no particles such as calcium carbonate and silica was obtained (hereinafter abbreviated as PET (II)).

(Preparation of polyethylene terephthalate pellet (PET (III)))
Except that the type and content of the particles of PET (I) were changed to 0.75% by mass of synthetic calcium carbonate having an average particle size of 0.9 μm obtained by adhering ammonium salt of polyacrylic acid at 1% by mass per calcium carbonate. A PET chip was obtained in the same manner as PET (I) (hereinafter abbreviated as PET (III)). The lubricant content in the PET chip was 0.75% by mass.

(Production of laminated film X1)
After drying these PET chips, they are melted at 285 ° C., melted at 290 ° C. by a separate melt extruder extruder, and a filter obtained by sintering a stainless steel fiber having a 95% cut diameter of 15 μm; Two-stage filtration of a filter obtained by sintering stainless steel particles of 15 μm is performed, and the two are combined in the feed block. PET (I) is applied to the surface layer B (anti-release surface side layer), and PET (II) is applied to the surface. The layers are laminated so as to become the layer A (release side layer), extruded (casted) at a speed of 45 m / min into a sheet, electrostatically adhered and cooled on a casting drum at 30 ° C. by an electrostatic adhesion method, An unstretched polyethylene terephthalate sheet having an intrinsic viscosity of 0.59 dl / g was obtained. The layer ratio is calculated as PET (I) / PET (II
) = 60% / 40%. Next, the unstretched sheet was heated by an infrared heater, and then stretched 3.5 times in the longitudinal direction at a roll temperature of 80 ° C. due to a speed difference between the rolls. Then, it was guided to a tenter and stretched 4.2 times in the transverse direction at 140 ° C. Next, heat treatment was performed at 210 ° C. in the heat setting zone. Thereafter, a relaxation treatment of 2.3% was performed in the horizontal direction at 170 ° C. to obtain a biaxially stretched polyethylene terephthalate film X1 having a thickness of 31 μm. Sa of the surface layer A of the obtained film X1 was 2 nm, and Sa of the surface layer B was 28 nm.

(Production of laminated film X2)
The thickness was adjusted by changing the speed at the time of casting without changing the same layer configuration and stretching conditions as those of the laminated film X1, to obtain a biaxially stretched polyethylene terephthalate film X2 having a thickness of 25 μm. Sa of the surface layer A of the obtained film X2 was 3 nm, and Sa of the surface layer B was 29 nm.

(Laminated film X3)
A4100 (Cosmoshine (registered trademark), manufactured by Toyobo Co., Ltd.) having a thickness of 25 μm was used as the laminated film X3. A4100 has a structure in which particles are not substantially contained in the film, and a coating layer containing particles is provided on the surface layer B side by in-line coating. Sa of the surface layer A of the laminated film X3 was 1 nm, and Sa of the surface layer B was 2 nm.

(Laminated film X4)
As the laminated film X4, E5101 (Toyobo Ester (registered trademark) film, manufactured by Toyobo Co., Ltd.) having a thickness of 25 μm was used. E5101 has a configuration in which particles are contained in the surface layers A and B of the film. Sa of the surface layer A of the laminated film X4 was 24 nm, and Sa of the surface layer B was 24 nm.

(Production of laminated film X5)
PET (III) is laminated so as to be a surface layer B (anti-release surface side layer) and PET (II) is to be a surface layer A (release surface side layer), and the layer ratio is calculated by calculating the discharge amount of each extruder. A biaxially stretched polyethylene terephthalate film X5 having a thickness of 31 μm was obtained in the same manner as for the laminated film X1, except that PET (III) / (II) was set to 80% / 20%. Sa of the surface layer A of the obtained film X5 was 2 nm, and Sa of the surface layer B was 30 nm.

(Resin solution A) Long-chain alkyl group-containing acrylic polyol Stearyl (meth) acrylate 20 mol%, hydroxyethyl (meth) acrylate 40 mol%, methyl (meth) acrylate 40 mol% are mixed at a ratio of 40 mol% The mixture was diluted with toluene so that the concentration became 40% by mass, and azobisisobutyronitrile was added in an amount of 0.5 mol% under a nitrogen stream to carry out copolymerization to obtain a resin solution A. The weight average molecular weight of the obtained polymer was 30,000.

(Example 1)
The coating solution 1 having the following composition was passed through a filter capable of removing 99% or more of foreign substances having a size of 0.5 μm or more on the surface layer A of the laminated film X1, and the coating film thickness (wet amount) was 5 g / After coating so as to obtain m ² , it was adjusted to enter the initial drying furnace in 0.5 seconds. After drying in an initial drying oven at 100 ° C. for 2 seconds, the product was continuously heated and cured at 130 ° C. for 7 seconds. Eight seconds after the heat curing step, the resultant was wound into a roll to obtain a release film for producing an ultra-thin ceramic green sheet. Table 1 shows the results obtained by measuring the film thickness, surface roughness, surface free energy, curl, and the like of the obtained release film. In addition, when the obtained release film was coated with a ceramic slurry and evaluated for coating properties, releasability, and pinholes, good evaluation results were obtained.
(Coating liquid 1) Solid content: 1.0% by mass, surface tension: 27 mN / m, viscosity: 5 mPa · s
Methyl ethyl ketone 57.93 parts by mass Toluene 40.00 parts by mass Resin solution A 1.75 parts by mass (long chain alkyl group-containing acrylic polyol, solid content 40%)
0.25 parts by mass of crosslinking agent (hexamethoxymethylolmelamine, solid content 100%)
0.05 parts by mass of silicone release agent (polyether-modified polydimethylsiloxane, TSF4446, solid content 100%, manufactured by Momentive)
Acid catalyst (p-toluenesulfonic acid) 0.02 parts by mass

(Examples 2 to 4, Comparative Examples 1 and 7)
A release film for producing an ultra-thin ceramic green sheet was prepared in the same manner as in Example 1, except that the composition of the coating liquid 1 was changed so as to have the ratio shown in Table 1. When the obtained release film was evaluated, the peeling force was good and good results were obtained for the examples containing the silicone-based release agent, but the peeling force was good for Comparative Example 1 containing no silicone-based release agent. And when the ceramic green sheet was peeled from the release film, defects such as pinholes were likely to occur. In Comparative Example 7 in which the amount of the silicone-based release agent was small and the ratio of the Si element on the surface of the release layer was low, the in-plane peeling uniformity was poor.

(Examples 5 to 7, Comparative Example 2)
The ultra-thin ceramic green sheet was prepared in the same manner as in Example 1 except that the solid content was changed as shown in Table 2 while the resin ratio of the coating liquid 1 was unchanged, and the coating amount (solid content) of the release layer was changed. A production release film was prepared.
When the obtained release film was evaluated, the examples in which the coating amount of the release layer was 0.2 g / m ² or less showed good results without curling. In Comparative Example 2 at 75 g / m ^2, the curl was significantly deteriorated. In Comparative Example 2, the content of the silicone-based release agent contained in the release layer was large, and the Si element ratio on the outermost surface of the release layer was increased, and the peeling stability tended to be deteriorated.

(Example 8)
A release film for producing an ultra-thin ceramic green sheet was prepared in the same manner as in Example 1 except that coating liquid 1 was changed to coating liquid 8.
(Coating liquid 8)
Methyl ethyl ketone 57.35 parts by mass Toluene 40.00 parts by mass Cymac (registered trademark) US270 2.33 parts by mass (acrylic polyol containing silicone group, manufactured by Toagosei Co., Ltd., solid content 30%)
0.25 parts by mass of crosslinking agent (hexamethoxymethylolmelamine, solid content 100%)
0.05 parts by mass of silicone release agent (polyether-modified polydimethylsiloxane, TSF4446, solid content 100%, manufactured by Momentive)
Acid catalyst (p-toluenesulfonic acid) 0.02 parts by mass

(Example 9)
A release film for producing an ultra-thin ceramic green sheet was prepared in the same manner as in Example 1 except that the coating liquid 1 was changed to the coating liquid 9.
(Coating liquid 9)
Methyl ethyl ketone 58.03 parts by mass Toluene 40.00 parts by mass Tesfine 305 1.90 parts by mass (long chain alkyl group-containing amino alkyd resin, manufactured by Hitachi Chemical, solid content 50%)
0.05 parts by mass of silicone release agent (polyether-modified polydimethylsiloxane, TSF4446, solid content 100%, manufactured by Momentive)
Acid catalyst (p-toluenesulfonic acid) 0.02 parts by mass

(Example 10)
A release film for producing an ultra-thin ceramic green sheet was prepared in the same manner as in Example 1, except that the coating liquid 1 was changed to the coating liquid 10.
(Coating liquid 10)
Methyl ethyl ketone 57.55 parts by mass Toluene 40.00 parts by mass Tesfine 322 2.38 parts by mass (long chain alkyl group-containing aminoacrylic resin, manufactured by Hitachi Chemical Co., Ltd., solid content 40%)
0.05 parts by mass of silicone release agent (polyether-modified polydimethylsiloxane, TSF4446, solid content 100%, manufactured by Momentive)
Acid catalyst (p-toluenesulfonic acid) 0.02 parts by mass

(Example 11)
An ultra-thin ceramic green sheet was prepared in the same manner as in Example 1 except that the coating solution 11 in which the resin solution A of the coating solution 1 was changed to 6AN-5000 (an acrylic resin containing no long-chain alkyl group) of the coating solution 10 was used. A production release film was prepared.
(Coating liquid 11)
Methyl ethyl ketone 57.93 parts by mass Toluene 40.00 parts by mass 6AN-5000 1.75 parts by mass (acryl polyol, manufactured by Taisei Fine Chemical Co., solid content 40%)
0.25 parts by mass of crosslinking agent (hexamethoxymethylolmelamine, solid content 100%)
0.05 parts by mass of silicone release agent (polyether-modified polydimethylsiloxane, TSF4446, solid content 100%, manufactured by Momentive)
Acid catalyst (p-toluenesulfonic acid) 0.02 parts by mass

(Example 12)
A release film for producing an ultra-thin ceramic green sheet was prepared in the same manner as in Example 1 except that the coating liquid 1 was changed to the coating liquid 12.
(Coating liquid 12)
Methyl ethyl ketone 58.95 parts by mass Toluene 40.00 parts by mass Hexamethoxymethylolmelamine 0.95 parts by mass (solid content 100%)
0.05 parts by mass of silicone release agent (polyether-modified polydimethylsiloxane, TSF4446, solid content 100%, manufactured by Momentive Performance Materials)
Acid catalyst (p-toluenesulfonic acid) 0.05 parts by mass

良好 Good results were obtained even when the binder component was changed as in Examples 8 to 12. Even when a resin containing a long-chain alkyl group or a silicone skeleton as a binder component was processed under the same conditions, a tendency was observed that surface protrusions became lower.

(Example 13)
A release film for producing an ultra-thin ceramic green sheet was prepared in the same manner as in Example 1 except that the coating liquid 1 was changed to the coating liquid 13.
(Coating liquid 13)
Methyl ethyl ketone 57.78 parts by mass Toluene 40.00 parts by mass Resin solution A 1.75 parts by mass (long chain alkyl group-containing acrylic polyol, solid content 40%)
0.25 parts by mass of crosslinking agent (hexamethoxymethylolmelamine, solid content 100%)
0.08 parts by mass of silicone release agent (polyester-modified polydimethylsiloxane, BYK-310, solid content 25%, manufactured by BYK Japan KK)
Acid catalyst (p-toluenesulfonic acid) 0.02 parts by mass

(Example 14)
A release film for producing an ultra-thin ceramic green sheet was prepared in the same manner as in Example 1 except that the coating liquid 1 was changed to the coating liquid 14.
(Coating liquid 14)
Methyl ethyl ketone 57.93 parts by mass Toluene 40.00 parts by mass Resin solution A 1.75 parts by mass (long chain alkyl group-containing acrylic polyol, solid content 40%)
0.25 parts by mass of crosslinking agent (hexamethoxymethylolmelamine, solid content 100%)
0.02 parts by mass of silicone release agent (carboxyl-modified polydimethylsiloxane, X22-3710, solid content 100%, manufactured by Shin-Etsu Chemical Co., Ltd.)
Acid catalyst (p-toluenesulfonic acid) 0.02 parts by mass

(Example 15)
A release film for producing an ultra-thin ceramic green sheet was prepared in the same manner as in Example 1 except that the coating liquid 1 was changed to the coating liquid 15.
(Coating liquid 15)
Methyl ethyl ketone 57.78 parts by mass Toluene 40.00 parts by mass Resin solution A 1.75 parts by mass (long chain alkyl group-containing acrylic polyol, solid content 40%)
0.25 parts by mass of crosslinking agent (hexamethoxymethylolmelamine, solid content 100%)
0.08 parts by mass of silicone-based release agent (polyester modified hydroxyl group-containing polydimethylsiloxane, BYK-370, solid content 25%, manufactured by BYK Japan KK)
Acid catalyst (p-toluenesulfonic acid) 0.02 parts by mass

In Examples 13 to 15 in which the type of the silicone-based release agent was changed, good evaluation results were obtained, but those having no hydroxyl group that reacts with the crosslinking agent (melamine in this example) were the same. Under the conditions, there was a tendency that the Si element ratio on the outermost surface of the release layer was high and the releasability was good.

(Examples 16 to 18, Comparative Example 3)
A release film for producing an ultra-thin ceramic green sheet was prepared in the same manner as in Example 1, except that the substrate film of Example 1 was changed to the substrate film shown in Table 1.
When the obtained release film was evaluated, in Examples 1 to 15 and 16 to 18 in which X1, X2, X3 and X5 containing no particles were used in the surface layer A of the substrate film, the surface layer A of the release layer was , P was low and the pinhole evaluation was good, whereas in Comparative Example 3 where X4 containing particles was used in the surface layer A of the base film and the coating amount of the release layer was relatively small and thin, Both Sa and P on the surface of the layer were high, resulting in poor pinhole evaluation.

(Examples 19 to 22, Comparative Examples 4 and 5)
Regarding the manufacturing conditions of Example 1, the ultra-thin film was prepared in the same manner as in Example 1 except that the time from coating to entering the initial drying furnace, or the temperature and passing time of the initial drying furnace were changed to the conditions shown in Table 2. A release film for producing a multilayer ceramic green sheet was prepared.

(Comparative Example 6)
A release film for producing an ultra-thin ceramic green sheet was produced in the same manner as in Example 11, except that the production conditions of Example 11 were changed to the conditions described in Table 1.

(Comparative Example 8)
A release film for producing an ultra-thin ceramic green sheet was prepared in the same manner as in Comparative Example 4, except that the content of the silicone-based release agent was changed to that shown in Table 1.

When the obtained film was evaluated, after coating, the time required to enter the initial drying furnace was 1.5 seconds or less, and the time required for passage through the initial drying furnace was 1.0 seconds or more and 3.0 seconds or less. Although the surface roughness Sa and the maximum protrusion height P of the mold layer surface were low and the pinhole evaluation was good, in the comparative example where the above conditions were not satisfied, aggregation of the mold release layer was observed and the surface of the mold release layer was observed. As a result, the roughness Sa and the maximum projection height P were increased. Further, in Comparative Examples 4 and 8 in which the passage time in the initial drying step was shortened, there was a tendency that precipitation of the silicone release agent on the surface of the release layer was small and the Si element ratio on the outermost surface of the release layer was low. In particular, in Comparative Example 8, the result was that the Si element ratio on the outermost surface of the release layer was reduced, and the peeling stability was deteriorated.

According to the present invention, as a release layer of the release film for producing a ceramic green sheet, by at least a composition containing a binder component and a silicone-based release agent is cured, at the time of drying the above components It has become possible to provide a release film having high smoothness and excellent releasability by suppressing deterioration of surface roughness due to aggregation. According to the present invention, even in the production of an ultra-thin ceramic green sheet having a thickness of 0.2 to 1.0 μm, the peelability is good and defects such as pinholes of the ceramic green sheet can be reduced.

Claims

Using a polyester film as a base material, the base material has a surface layer A substantially free of particles on at least one surface, and is released on at least one surface of the surface layer A directly or via another layer. A release film in which layers are laminated, wherein the release layer is formed by curing a composition containing a binder component and a silicone-based release agent, and the Si element ratio on the release layer surface is 2.0 at% or more. A release film for producing a ceramic green sheet, which has a maximum protrusion height (P) of 50 nm or less and a region average roughness (Sa) of 1.5 nm or less at 10.0 at% or less, and a release layer surface.
The release film for producing a ceramic green sheet according to claim 1, wherein the silicone release agent is a silicone resin having a polyether moiety or a carboxyl group.
3. The release film for producing a ceramic green sheet according to claim 1, wherein the silicone-based release agent-derived component is contained in the release layer in an amount of 1 to 15 mg / m 2 .
4. The release film for producing a ceramic green sheet according to claim 1, wherein the binder component contains a resin having a long-chain alkyl group and / or a silicone skeleton.
A method for producing a ceramic green sheet using the release film for producing a ceramic green sheet according to any one of claims 1 to 4, wherein the molded ceramic green sheet has a thickness of 0.2 μm to 1 μm. A method for producing a ceramic green sheet having a thickness of 0.0 μm.
A method for manufacturing a ceramic capacitor, which employs the method for manufacturing a ceramic green sheet according to claim 5.