JP2021091230A - Release film for producing ceramic green sheet - Google Patents

Abstract

To provide a release film for producing a ceramic green sheet maintaining the high smoothness of the surface of a release layer of a release film, having low peel force even when a peel angle is low upon the production of a ceramic green sheet compared with the conventional release film for producing a ceramic green sheet, and having low peel force upon peeling even in the production of an ultrathin layer ceramic green sheet.SOLUTION: There is provided a release film using a polyester film as a base material, in which at least one side of the base material contains a surface layer A substantially not including inorganic particles, and a release layer is laminated on the surface of the surface layer A in at least one side directly or via the other layer. When ceramic green sheet molding is performed to the surface of the release layer, a peel temperature between the ceramic green sheet and the release film reaches 50°C, and peel force F (T50/A30) at a peel angle of 30° reaches 60 mN/mm or lower.SELECTED DRAWING: Figure 1

Description

The present invention relates to a release film for manufacturing a ceramic green sheet, and more specifically, during production of an ultrathin ceramic green sheet, the ceramic green sheet and the release film are peeled even when the peeling temperature is high and the peeling angle is low. The present invention relates to a release film for manufacturing an ultra-thin ceramic green sheet, which has low force and can suppress damage to the ceramic green sheet.

Conventionally, a release film in which a polyester film is used as a base material and a release layer is laminated on the polyester film is used for molding a ceramic green sheet such as a laminated ceramic capacitor and a ceramic substrate. In recent years, with the miniaturization and large capacity of multilayer ceramic capacitors, the thickness of the ceramic green sheet tends to be reduced. The ceramic green sheet is molded by applying a slurry containing a ceramic component such as barium titanate and a binder resin to a release film and drying it. A multilayer ceramic capacitor is manufactured by printing an electrode on a molded ceramic green sheet, peeling it from a release film, laminating and pressing the ceramic green sheet, firing, and applying an external electrode. When a ceramic green sheet is molded on the surface of the release layer of a polyester film, there is a problem that minute protrusions on the surface of the release layer affect the molded ceramic green sheet, which tends to cause defects such as cissing and pinholes. there were. Therefore, various methods for realizing a release layer surface having excellent flatness have been developed (for example, Patent Document 1).

However, in recent years, further thinning of the ceramic green sheet has progressed, and a ceramic green sheet having a thickness of 1.0 μm or less, more specifically 0.2 μm to 1.0 μm, has been required. Therefore, since the strength of the ceramic green sheet is lowered, it has become necessary not only to smooth the surface of the release layer but also to reduce and uniformly release the ceramic green sheet when it is peeled from the release film. .. That is, it is becoming more important to minimize the force applied to the ceramic green sheet when peeling the ceramic green sheet from the release film so as not to damage the ceramic green sheet.

As a method for peeling the ceramic green sheet, a method has been proposed in which the ceramic green sheet side is fixed to a suction head and the release film, which is a carrier film, is peeled off from the end portion (for example, Patent Document 2). In the case of Patent Document 2, it can be seen from the dimensions of the apparatus that the peeling angle is as low as about 3 °. It is generally known that the peeling force becomes heavier when the peeling angle is lower than 90 ° (for example, Non-Patent Document 1). Further, the head for peeling the ceramic sheet from the release film and the head for laminating may be the same. In this case, a constant temperature is applied to the peeling head in order to fuse the binders in the ceramic sheet to each other during lamination.

In recent years, it has been found that the surface of the release layer becomes smooth by using an ultraviolet curable resin. At the same time, it has been found that the silicone-based component contained in the release layer or a cured product thereof is excellent in peelability from the ceramic sheet (see, for example, Patent Document 3).

However, according to the method described in Patent Document 3, the silicone component is likely to segregate on the surface of the release layer during the release layer processing, and surface hardening inhibition peculiar to radical polymerization occurs. There was a problem that the solvent property was deteriorated. If the solvent resistance near the surface of the release layer is poor, the surface of the release layer is eroded by organic solvents used during ceramic green sheet processing and internal electrode printing, such as toluene, and the ceramic green sheet is particularly eroded at low angles and high temperatures. There is a problem that the peeling force at the time of peeling is remarkably increased and the ceramic sheet is damaged. From the above, we focused on the fact that the release layer, which has low peeling force at low angles and low peeling force even at high temperature peeling, is effective in reducing damage to the ceramic green sheet, and led to the present invention. It was.

Japanese Unexamined Patent Publication No. 2000-117899 Japanese Unexamined Patent Publication No. 2004-031489 International Publication No. 2013/145864

Inao, Saeki, Sugisaki, Shimizu, Inaba, Kishimoto, "Peeling energy and its effect at the adhesive / peeling agent interface", Journal of the Japan Adhesive Society, Vol.48, No.9, p. 308-313, 2012

As a result of diligent studies in view of the above circumstances, the present invention maintains high smoothness of the release layer surface of the release film in order to prevent damage to the ceramic green sheet, and is used for conventional ceramic green sheet production. Compared to the release film, the peeling force is low even when the peeling angle is low during the production of the ceramic green sheet, and the peeling force during the peeling is low even when the ultrathin layer ceramic green sheet with a thickness of 1 μm or less is manufactured. It is intended to provide a release film for sheet production.

As a result of diligent studies to solve the above problems, the present inventors have provided a release layer on at least one side of a polyester film, and the peeling temperature between the ceramic sheet coated on the release layer and the release layer is 50. It has been found that a release film for producing a ceramic green sheet having excellent peelability of a ceramic green sheet can be provided by setting the peeling force F (T50 / A30) at ° C. and a peeling angle of 30 ° to 60 mN / mm or less.

That is, the present invention has the following configuration.
1. 1. A polyester film is used as a base material, and the base material has a surface layer A having substantially no inorganic particles on at least one side thereof, and is separated on the surface of the surface layer A on at least one side directly or via another layer. A release film in which mold layers are laminated, and when a ceramic green sheet is molded on the release layer, the release force F between the ceramic green sheet and the release film at a release temperature of 50 ° C. and a release angle of 30 °. A release film for manufacturing a ceramic green sheet having (T50 / A30) of 60 mN / mm or less.
2. The ceramic green sheet production according to the first aspect, wherein the film elastic modulus measured from the surface of the release layer opposite to the base material by the nanoindentation test on the release layer is 2.0 GPa or more. Release film for use.
3. 3. The ceramic green according to the first or second above, wherein the release layer is obtained by curing a coating film containing at least a release agent and a binder component, and the binder component is 85% by mass or more of the solid content of the release layer. Release film for sheet manufacturing.
4. The release film for producing a ceramic green sheet according to the third item, wherein the release agent contains a silicone skeleton, and the content of the release agent is 15% by mass or less with respect to the solid content of the release layer.
5. The release film for producing a ceramic green sheet according to any one of the first to fourth above, wherein the release layer has a film thickness of 0.01 μm to 1.5 μm.
6. The release film for producing a ceramic green sheet according to any one of the third to fifth above, wherein the binder component is at least one crosslinked product of a melamine compound, an epoxy compound, and an acrylate compound.
7. The surface layer B forming the surface layer opposite to the surface layer A of the polyester film base material contains particles, the particles are silica particles and / or calcium carbonate particles, and the total of the particles is the surface layer B. The release film for producing a ceramic green sheet according to any one of 1 to 6 above, which contains 5000 to 15000 ppm.
8. A method for manufacturing a ceramic green sheet, wherein the ceramic green sheet is molded by using the release film for manufacturing the ceramic green sheet according to any one of the first to seventh above, 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.
9. A method for manufacturing a ceramic capacitor, which employs the method for manufacturing a ceramic green sheet according to the eighth item.

The release film for manufacturing a ceramic green sheet of the present invention has a smooth surface of the release layer, and when the peeling angle is lower during the production of the ceramic green sheet as compared with the conventional release film for producing a ceramic green sheet. However, the peeling force is low, damage to the ceramic green sheet is suppressed, and an ultrathin layer ceramic green sheet having a thickness of 0.2 to 1.0 μm can be produced.

It is a schematic diagram for demonstrating the measuring method of the peeling force in this invention.

Hereinafter, the present invention will be described in detail.

The release film for producing a ceramic green sheet of the present invention has a surface layer A substantially free of inorganic particles on at least one side of the polyester film, and is directly on the surface of the surface layer A on at least one side or another. The release layer is laminated via the layer, and the release force F (T50 / A30) at a release temperature of 50 ° C. and a release angle of 30 ° between the ceramic sheet applied on the release layer and the release layer is 60 mN. It is preferably / mm or less.

(Polyester film)
The polyester constituting the polyester film used as the base material in the present invention is not particularly limited, and a film-molded polyester usually generally used as a base material for a release film can be used, but it is preferable. It is preferably a crystalline linear saturated polyester composed of an aromatic dibasic acid component and a diol component, for example, polyethylene terephthalate, polyethylene-2,6-naphthalate, polybutylene terephthalate, polytrimethylene terephthalate or resins thereof. A copolymer containing a constituent component as a main component is more preferable, and a polyester film formed from polyethylene terephthalate is particularly preferable. The repeating unit of ethylene terephthalate is preferably 90 mol% or more, more preferably 95 mol% or more, and other dicarboxylic acid components and diol components may be copolymerized in a small amount, but from the viewpoint of cost. , Preferably made only from terephthalic acid and ethylene glycol. Further, known additives such as antioxidants, light stabilizers, ultraviolet absorbers, crystallization agents and the like 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 because of its high bidirectional elastic modulus and the like.

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. On the contrary, when it is 0.70 dl / g or less, it is preferable because the cutability when cutting to a predetermined product width is good and dimensional defects do not occur. Further, it is preferable that the raw material pellets are sufficiently vacuum dried.

The method for producing the polyester film in the present invention is not particularly limited, and a method generally used in the past can be used. For example, the polyester can be obtained by melting the polyester with an extruder, extruding it into a film, and cooling it with a rotary cooling drum to obtain an unstretched film, and biaxially stretching the unstretched film. The biaxially stretched film can be obtained by a method of sequentially biaxially stretching a longitudinally or laterally uniaxially stretched film in the lateral or longitudinal direction, or a method of simultaneously biaxially stretching an unstretched film in the longitudinal and horizontal directions. You can.

In the present invention, the stretching temperature at the time of stretching the polyester film is preferably set to be equal to or higher than the secondary transition point (Tg) of the polyester. It is preferable to stretch 1 to 8 times, particularly 2 to 6 times in each of the vertical and horizontal directions.

The thickness of the polyester film is preferably 12 to 50 μm, more preferably 15 to 38 μm, and even more preferably 19 μm to 33 μm. When the thickness of the film is 12 μm or more, it is preferable because there is no possibility of deformation due to heat during film production, the processing process of the release layer, and the molding of the ceramic green sheet and the like. On the other hand, when the thickness of the film is 50 μm or less, the amount of the film discarded after use does not become extremely large, which is preferable in reducing the environmental load.

The polyester film base material may be a single layer or a multilayer of two or more layers, but it is preferable that the polyester film base material has a surface layer A substantially free of inorganic particles on at least one side thereof. 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 or the like on the opposite surface of the surface layer A which does not substantially contain inorganic particles. As for the laminated structure, if the layer to which the release layer is applied is the surface layer A, the layer on the opposite surface is the surface layer B, and the core layers other than these are the layer C, the layer structure in the thickness direction is the release layer / A laminated structure such as A / B or a release layer / A / C / B can be mentioned. As a matter of course, the layer C may have a plurality of layer configurations. 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 in a roll shape.

In the polyester film base material of the present invention, it is preferable that the surface layer A forming the surface to which the release layer is applied does not substantially contain inorganic particles. At this time, the region surface average roughness (Sa) of the surface layer A is preferably 7 nm or less. When Sa is 7 nm or less, pinholes and the like are less likely to occur during molding of the ultra-thin ceramic green sheet to be laminated, which is preferable. It can be said that the smaller the region 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 does not substantially contain inorganic particles, and the region surface average roughness (Sa) after laminating the coat layer is in the above range. It is preferable to enter. In the present invention, "substantially free of inorganic particles" means a content of 50 ppm or less, preferably 10 ppm or less, most preferably detection limit or less when the inorganic element is quantified by Keiko X-ray analysis. To do. This means that even if inorganic particles are not actively added to the film, contamination components derived from foreign substances and stains attached to the raw material resin or the line or device in the film manufacturing process are peeled off and mixed into the film. This is because there are cases.

In the polyester film base material of the present invention, the surface layer B forming the opposite surface 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 total amount of particles contained in the surface layer B is preferably 5000 to 15000 ppm. At this time, the region 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 amount of silica particles and / or calcium carbonate particles is 5000 ppm or more and Sa is 1 nm or more, air can be released uniformly when the film is rolled up, and the rolled shape is good and the flatness is good. , Suitable for manufacturing ultra-thin ceramic green sheets. Further, when the total amount of silica particles and / or calcium carbonate particles is 15,000 ppm or less and Sa is 40 nm or less, the lubricant is less likely to aggregate and coarse protrusions cannot be formed, so that the quality is stable during the production of an ultrathin ceramic green sheet. It is preferable.

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 and hydroxyapatite particles. Examples of the heat-resistant organic particles include crosslinked polyacrylic particles, crosslinked polystyrene particles, and benzoguanamine particles. When silica particles are used, porous colloidal silica is preferable, and when calcium carbonate particles are used, light calcium carbonate surface-treated with a polyacrylic acid-based polymer compound is preferable from the viewpoint of preventing the lubricant from falling off. ..

The average particle size of the particles added to the surface layer B is preferably 0.1 μm or more and 2.0 μm or less, and particularly preferably 0.5 μm or more and 1.0 μm or less. When the average particle size 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, pinholes are not likely to occur in the ceramic green sheet due to the coarse particles on the surface of the release layer, which is preferable.

The surface layer B may contain two or more types of particles having different materials. Further, particles of the same type having different average particle diameters may be contained.

The average particle size of the particles is measured by observing the particles in the cross section of the processed film with a transmission electron microscope or a scanning electron microscope, observing 100 non-aggregated particles, and maximizing the maximum of each particle. The particle size is defined as the particle size, and the average value thereof is used as the average particle size.

When the surface layer B does not contain particles, it is preferable that a coat layer containing particles on the surface layer B has slipperiness. The coating layer is not particularly limited, but is preferably provided by an in-line coating that is applied during the film formation of the polyester film. When 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 region for the same reason as the above-mentioned region surface average roughness (Sa) of the surface layer B. The surface average roughness (Sa) is preferably in the range of 1 to 40 nm. More preferably, it is in the range of 5 to 35 nm.

From the viewpoint of reducing pinholes, it is preferable not to use a recycled raw 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 lubricant from being mixed.

The thickness ratio of the surface layer A, which is the layer on which 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, it is not easily affected by the particles contained in the surface layer B or the like from the inside of the film, and it is easy for the region surface average roughness Sa to satisfy the above range, which is preferable. When it is 50% or less of the thickness of all the layers of the base film, the ratio of the recycled raw material used in the surface layer B can be increased, and the environmental load is reduced, which is preferable.

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

In addition, a film before or after uniaxial stretching in the film forming process on the surface of the surface layer A and / or the surface layer B in order to improve the adhesion of the release layer to be applied later and prevent charging. A coat layer may be provided on the surface, or a corona treatment or the like may be applied.

(Release layer)
The release layer in the present invention is preferably formed by curing a coating film containing at least a release agent and a binder component. The release layer in the present invention preferably has a high crosslink density. By increasing the crosslink density, the elastic modulus is also improved, so that the peeling force at high temperature and low angle can be lowered by reducing the deformation at the time of peeling. Further, it is also preferable that the surface of the release layer has high solvent resistance in terms of reducing the peeling force at high temperature and low angle. Since the surface of the release layer has high solvent resistance, it is possible to prevent erosion of the surface of the release layer by the solvent during slurry coating. The peeling force can be reduced by reducing the deformation of the surface of the release layer due to solvent erosion. Further, it is also preferable that the release agent in the release layer is appropriately segregated on the surface while maintaining the interaction with the binder, from the viewpoint of reducing the peeling force at high temperature and low angle.

The binder component contained in the release layer in the present invention is not particularly limited, but it is preferable that the component that can be crosslinked is crosslinked in order to increase the crosslink density of the release layer. As the binder component, a thermosetting resin, an ultraviolet curable resin, or the like can be used. The release agent, binder component, etc., which are constituent substances in the coating liquid and coating film before cross-linking and curing, may change in chemical structure in the release layer after cross-linking and curing. Since it is difficult to describe the chemical structure itself in the crosslinked and cured state, the release layer expresses that the coating film containing at least the release agent and the binder component is cured.

The binder component contained in the release layer in the present invention preferably contains two or more reactive functional groups in one molecule. Having two or more functional groups is preferable because the crosslink density can be increased.

Suitable binder components for thermosetting resins include melamine compounds. It is preferable to use a melamine compound because a release layer having a high crosslink density can be obtained.

(Melamine compound)
The melamine-based resin used for the release layer in the present invention may be a general one and is not particularly limited, but is obtained by condensing melamine and formaldehyde, and has a triazine ring, a methylol group and / or an alkoxy in one molecule. It is preferable to have one or more methyl groups each. Specifically, a compound obtained by dehydrating and condensing a methylalcohol melamine derivative obtained by condensing melamine and formaldehyde with methyl alcohol, ethyl alcohol, isopropyl alcohol, butyl alcohol and the like as lower alcohols to etherify them is preferable. Examples of the methylolated melamine derivative include monomethylol melamine, dimethylol melamine, trimethylol melamine, tetramethylol melamine, pentamethylol melamine, and hexamethylol melamine. One type may be used or two or more types may be used.

The release layer in the present invention preferably has a high crosslink density and a high elastic modulus in order to reduce the peeling force. Therefore, as the melamine-based resin used for the release layer, it is preferable to use hexamethylol melamine having many cross-linking points in one molecule, which can increase the cross-linking density of the release layer.

When an ether compound dehydrated and condensed with alcohol as a methylol melamine derivative is used as the melamine resin used for the release layer in the present invention, hexamethoxy obtained by dehydration condensation with methyl alcohol from the viewpoint of reactivity. Methylmelamine is particularly preferred.

The melamine-based resin used for the release layer in the present invention preferably has a weight average molecular weight of less than 1000. More preferably, the weight average molecular weight is less than 800, still more preferably less than 600. When the weight average molecular weight is less than 1000, the cross-linking reaction easily proceeds and a film having a higher cross-linking density can be formed, which is preferable. The weight average molecular weight in the present specification is a standard polystyrene-equivalent value measured by a gel permeation chromatography (GPC) method.

When a melamine-based compound is used as the binder for the release layer in the present invention, it is preferable to add a catalyst in order to promote the cross-linking reaction of the melamine-based compound. The catalyst to be used is not particularly limited, but an existing acid catalyst can be used, and carboxylic acid-based, metal salt-based, phosphoric acid ester-based, and sulfonic acid-based catalysts can be preferably used. In addition, a block type catalyst in which the acid moiety is blocked can also be used.

When a sulfonic acid system is used as the acid catalyst, for example, paratoluenesulfonic acid, xylenesulfonic acid, cumenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, trifluoromethanesulfonic acid and the like are preferably used. And paratoluenesulfonic acid can be used particularly preferably.

When a carboxylic acid system is used as the acid catalyst, for example, benzoic acid, acetic acid, formic acid, oxalic acid, propionic acid and derivatives thereof can be used. It is known that a carboxylic acid-based acid catalyst has weaker acidity and is inferior in reactivity as compared with other catalysts such as a sulfonic acid-based catalyst, but in the present invention, a carboxylic acid-based acid catalyst can also be sufficiently used. Further, since the carboxylic acid type has a slower reaction than the sulfonic acid type, the release agent is likely to segregate on the surface in the drying step, and the release effect can be exhibited by adding a smaller amount of the release agent. Therefore, it is preferable. In particular, 4-methylbenzoic acid is inexpensive, easily available, and easy to use.

The amount of the acid catalyst added is preferably 0.1 to 10% by mass with respect to the melamine-based resin contained in the release layer. More preferably, it is 0.5 to 8% by mass. More preferably, it is 0.5 to 5% by mass. When it is 0.1% by mass or more, the curing reaction easily proceeds, which is preferable. On the other hand, when it is 10% 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 of adversely affecting it, which is preferable.

Suitable binder components of the ultraviolet curable resin include cationic curable resins and radical curable resins. Examples of the cationic curing resin include epoxy compounds, ether compounds, and oxetane compounds. Further, as the radical curing resin, an acrylate compound can be preferably used. In the case of a cationically curable resin, the reactivity of the epoxy compound is high, which is preferable.

(Epoxy compound)
Examples of the epoxy group-containing compound used for the release layer in the present invention include glycidyl ether type, glycidyl amine type, glycidyl ester type epoxy, and alicyclic epoxy, and in particular, glycidyl ether type epoxy. The alicyclic epoxy is preferable, and the alicyclic epoxy is most preferable from the viewpoint of reactivity. Examples of the glycidyl ether type epoxy compound include aromatic glycidyl ether represented by bisphenol type epoxy resin and cresol novolac type epoxy resin, and aliphatic glycidyl ether represented by hydrogenated A type glycidyl ether and butyl glycidyl ether. Be done. Examples of the alicyclic epoxy include those introduced with an ester skeleton, a dicyclopentadiene skeleton, a fluorene skeleton, an ε-caprolactone skeleton, and the like, and may have other skeletons.

As the alicyclic epoxy compound, a commercially available one can also be used. Examples of commercially available products include Cyclomer (registered trademark) M100, Celoxide (registered trademark) 2000 (above, Daicel, monofunctional), Celoxide (registered trademark) 2021P, 2081 (above, Daicel, bifunctional). , Epolide (registered trademark) GT401 (manufactured by Daicel, tetrafunctional), EHPE (registered trademark) 3150 (manufactured by Daicel, polyfunctional) and the like.

The epoxy compound used for the release layer in the present invention may be used alone or in combination of two or more. Among these epoxy group-containing compounds, an alicyclic epoxy compound is particularly preferable, and a polyfunctional alicyclic epoxy resin having two or more functions in one molecule is more preferable.

(Cationic polymerization initiator)
When a cationic curing resin is used for the release layer in the present invention, it is preferable to use a cationic polymerization initiator. Examples of the cationic polymerization initiator include onium salts such as aryldiazonium salt, aryliodonium salt, arylhalonium salt, and arylsulfonium salt, and organic metal complexes such as iron-allene complex, titanosen complex, and arylsilanol-aluminum complex. Can be mentioned. These may be used alone or in combination of two or more.

Commercially available products include PCI-220, PCI-620 (manufactured by Nippon Kayaku Co., Ltd.), UVI6990 (manufactured by Union Carbide), SP-150, SP-152, SP-170, SP-172 (manufactured by Asahi Denka Kogyo Co., Ltd.). , Uvacure (registered trademark) 1590, 1591 (manufactured by Daicel UCB), Sun Aid (registered trademark) SI-110, SI-180, SI-100L, SI-80L, SI60L (manufactured by Sanshin Chemical Co., Ltd.), etc. ..

The amount of the cationic polymerization initiator added is not particularly limited. For example, it is preferable to use about 0.1 to 20% by mass with respect to the cationic cured resin used.

When a photocationic polymerization initiator is used as the cationic polymerization initiator, it is desirable to use it in combination with a photosensitizer. Examples of the photosensitizer include carbonyl compounds, organic sulfur compounds, persulfurized compounds, redox compounds, azo and diazo compounds, halogen compounds, photoreducing dyes and the like. Specific photosensitizers include, for example, benzoin derivatives such as benzoin methyl ether, benzoin isopropyl ether, α, α-dimethoxy-α-phenylacetophenone, benzophenone, 2,4-dichlorobenzophenone, ο-benzoyl benzoic acid. Methyl, benzophenone derivatives such as 4,4'-bis (dimethylamino) benzophenone, 4,4'-bis (dimethylamino) benzophenone, 2-chlorothioxanthone, thioxanthone derivatives such as 2-isopropylthioxanthone, 2-chloroanthraquinone , Anthraquinone derivatives such as 2-methylanthraquinone, N-methylacridone, acridone derivatives such as N-butylacridone, α, α-diethoxyacetophenone, benzyl, fluorenone, xanthone, uranyl compounds, halogen compounds and the like. Be done. However, it is not limited to these. Further, these may be used alone or in combination. The photosensitizer is preferably added in an amount of about 0.1 to 20% by mass with respect to the cationic curable resin.

(Acrylate compound)
The acrylate-based compound used for the release layer in the present invention is preferably a (meth) acrylate-based compound which is an ultraviolet curable resin. Since the (meth) acrylate compound has a very high reaction rate, the radical polymerization reaction proceeds instantly at the same time as the photopolymerization initiator is cleaved, and a coating film having a high crosslink density and a high elastic modulus can be formed. By increasing the elastic modulus of the release layer, the release layer does not deform and follow when peeled, and there is no risk of damaging the ceramic green sheet, which is preferable. The (meth) acrylate-based compound shown here refers to a group of compounds in which the metaacryloyl group and the acryloyl group contained in the molecule serve as cross-linking points and the radical curing reaction proceeds.

Examples of the (meth) acrylate-based compound include acrylate, methacrylate, and urethane acrylate. Each can be preferably used, but it is more preferable to use urethane acrylate. When urethane acrylate is used, the urethane bond in the molecule can form a hydrogen bond, so that the strength of the cured coating film can be further increased. Hereinafter, the description of urethane acrylate will be described as a term including urethane methacrylate.

The number of functional groups (the number of functional groups that can be cross-linking points in the radical curing reaction) in one molecule of the (meth) acrylate-based compound is preferably 4 or more from the viewpoint of increasing the cross-linking density, and is preferably 6 or more. More preferably, 7 or more is more preferable, and 9 or more is further preferable. The number of functional groups is not particularly limited, but is preferably 20 or less. When the value is 20 or less, the intramolecular reaction is more likely to proceed than the intermolecular cross-linking reaction, and the effect of improving the cross-linking density is not lost, which is preferable.

The (meth) acrylate-based compound to be used may be a monomer, an oligomer or a polymer, but it is preferable to use a monomer or an oligomer from the viewpoint of solubility in an organic solvent and handleability. These may be used alone or in combination of two or more.

When a monomer is used as the (meth) acrylate-based compound, for example, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tri (meth) acrylate, di Examples thereof include pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tri (meth) ethoxylated isocyanurate, caprolactone-modified dipentaerythritol hexa (meth) acrylate, and the like. ..

When an oligomer is used as the (meth) acrylate-based compound, for example, a polyfunctional (meth) acrylate-based oligomer, a polyester acrylate-based oligomer, an epoxy acrylate-based oligomer, a polyether acrylate-based oligomer, a polybutadiene acrylate-based oligomer, a silicone acrylate-based oligomer, or the like is used. Can be mentioned.

The urethane acrylate used in the present invention refers to a urethane acrylate having a urethane bond in the molecular chain and one or more radical curable functional groups selected from an acryloyl group and a methacryloyl group. The synthesis method is not particularly limited, but it can be obtained, for example, by reacting a polyhydric alcohol or an organic polyisocyanate with a hydroxyacrylate.

Examples of the polyhydric alcohol include neopentyl glycol, 3-methyl-1,5-pentanediol, ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, trimethylolpropane, and pentaerythritol. , Tricyclodecanedimethylol, bis- [hydroxymethyl] -cyclohexane, etc .; the above polyhydric alcohols and polybasic acids (eg, succinic acid, phthalic acid, hexahydrophthalic anhydride, terephthalic acid, adipic acid, azelaic acid, tetrahydroan anhydride) Polyol polyol obtained by reaction with phthalic acid, etc .; Polycaprolactone polyol obtained by reaction of the above polyhydric alcohol with ε-caprolactone; Obtained by reaction of polycarbonate polyol (for example, 1,6-hexanediol and diphenyl carbonate) Polyether polyols and the like); and polyether polyols. Examples of the polyether polyol include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, ethylene oxide-modified bisphenol A and the like.

Examples of the organic polyisocyanate include isophorone diisocyanate, hexamethylene diisocyanate, tolylene diisocyanate, xylene diisocyanate, diphenylmethane-4,4'-diisocyanate, dicyclopentanyl isocyanate and other isocyanate compounds, adducts of these isocyanate compounds, or these. Examples thereof include a multimer of isocyanate.

Examples of the hydroxy (meth) acrylate compound include pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and hydroxyethyl (meth). ) Acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, dimethylolcyclohexylmono (meth) acrylate, hydroxycaprolactone (meth) acrylate and the like can be mentioned. Of these, pentaerythritol tri (meth) acrylate and dipentaerythritol penta (meth) acrylate are preferable from the viewpoint of increasing the crosslink density.

As the urethane acrylate used in the present invention, a commercially available urethane acrylate can also be used. Examples of commercially available products are manufactured by Nippon Synthetic Chemical Industry Co., Ltd .: UV1700B (10 functionals), UV7620EA (9 functionals), UV7610B (9 functionals), UV7600B (6 functionals), UV7650B (5 functionals), manufactured by Nippon Kayaku Co., Ltd .: DPHA40H (10 functionals), UX5003 (6 functionals), Arakawa Chemical Industry Co., Ltd .: Beam set 577 (6 functionals), Taisei Fine Chemicals Co., Ltd .: 8UX-015A (15 functionals), and Shin-Nakamura Chemical Industry Co., Ltd .: U15HA (15) Sensory) and the like.

(Photoradical initiator)
When a radical polymerization type resin is used for the release layer in the present invention, it is preferable to add a photoradical polymerization initiator. Specific examples of the photoradical polymerization initiator include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, methyl benzoin benzoate, benzoin dimethyl ketal, 2, 4-Diethylthioxanthone, 1-hydroxycyclohexylphenylketone, benzyldiphenylsulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, β-chloranthraquinone, (2,4,6- Trimethylbenzyldiphenyl) phosphine oxide, 2-benzothiazole-N, N-diethyldithiocarbamate and the like can be mentioned. In particular, 2-hydroxy-1-{4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] -phenyl} -2-methylpropan-1-one, which is said to have excellent surface curability, 1-Hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propane-1-one, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1 -On is preferable, and 2-hydroxy-2-methyl-1-phenyl-propane-1-one and 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one are particularly preferable. preferable. These may be used alone or in combination of two or more.

The amount of the photoradical polymerization initiator added is not particularly limited. For example, it is preferable to use about 0.1 to 20% by mass with respect to the radical-based cured resin used.

The binder component contained in the release layer in the present invention is preferably contained in an amount of 85% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass, based on the solid content of the entire release layer. Is. By containing 85% by mass or more of the binder component, the release layer has a high crosslink density, the elastic modulus of the release layer can be increased, and the solvent resistance of the release layer surface can be improved, and the ceramic green sheet can be peeled off. Sometimes it can be peeled off with a low peeling force. In the present invention, components other than the binder component and the release agent component in the release layer, such as the residual solvent, acid catalyst, photocation initiator and photoradical initiator, are volatile or trace amounts, and the present invention In the above, the solid content of the entire release layer is the total value of the solid content of the binder component and the release agent.

(Release agent)
As the release agent (additive for improving the releasability of the release layer) used for the release layer in the present invention, a silicone-based additive or a non-silicone-based additive such as an olefin-based, long-chain alkyl-based, or fluorine-based additive is added. Agents and the like can be used, but it is preferable to use a silicone-based additive from the viewpoint of releasability.

The silicone-based additive is a compound having a silicone skeleton in the molecule, and polyorganosiloxane or the like can be preferably used. Further, an acrylic resin or an alkyd resin having polyorganosiloxane in the side chain can also be used. Among the polyorganosiloxanes, polydimethylsiloxane (abbreviation, PDMS) can be preferably used, and those having a functional group as a part of polydimethylsiloxane are also preferable. Having a functional group is preferable because it facilitates the development of intermolecular interactions such as hydrogen bonds with the binder component and improves the solvent resistance of the surface of the release layer.

As the reactive functional group to be introduced into the polydimethylsiloxane, an amino group, an epoxy group, a hydroxy group, a mercapto group, a carboxyl group, a methacryl group, an acrylic group and the like can be used. 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.

When a melamine-based compound is used as the binder, it is not particularly limited, but it is preferable to use a carboxyl group-modified polydimethylsiloxane that exhibits an appropriate interaction with the hydroxyl group of the melamine-based compound. It is preferable to use the compound because it exhibits an interaction with the binder while appropriately segregating on the surface of the release layer, and thus the solvent resistance of the surface of the release layer can be increased. By improving the solvent resistance of the surface of the release layer, it is possible to reduce the peeling force at a low angle and at a high temperature, which is preferable.

The carboxyl group-modified polydimethylsiloxane may be one in which a carboxyl group is directly bonded to the silicon atom of the polydimethylsiloxane, but one in which a carboxyl group is bonded to polydimethylsiloxane via an alkyl group or an aryl group. There may be. However, those in which a carboxyl group is bonded to polydimethylsiloxane via an organic group having a repeating structure such as polyether, polyester, or polyurethane are not so preferable.

When an epoxy compound is used as the binder, it is preferable to use epoxy-modified polydimethylsiloxane in consideration of the reactivity between the binder and polydimethylsiloxane. It is preferable to use the compound because it exhibits an interaction with the binder while appropriately segregating on the surface of the release layer, and thus the solvent resistance of the surface of the release layer can be increased. By improving the solvent resistance of the surface of the release layer, it is possible to reduce the peeling force at a low angle and at a high temperature, which is preferable.

When an acrylate compound is used as the binder, it is preferable to use an energy ray-curable copolymer polymer having a (meth) acryloyl group and a polyorganosiloxane group in the molecule. It is preferable to use the compound because it exhibits an interaction with the binder while appropriately segregating on the surface of the release layer, and thus the solvent resistance of the surface of the release layer can be increased. By improving the solvent resistance of the surface of the release layer, it is possible to reduce the peeling force at a low angle and at a high temperature, which is preferable.

The release layer in the present invention preferably contains a release agent in an amount of 0.1% by mass or more and 15% by mass or less based on the solid content of the entire release layer. More preferably, it is 0.5% by mass or more and 10% by mass or less, and further preferably 0.5% by mass or more and 5% by mass or less. When it is 0.1% by mass or more, the releasability is improved and the peelability of the ceramic green sheet is improved, which is preferable. On the other hand, when it is 15% by mass or less, the elastic modulus of the entire release layer and the solvent resistance of the release layer surface do not decrease too much, and the release layer is deformed when the ceramic green sheet is peeled, and the release force is large. It is preferable because it is difficult to become. At this time, the solid content of the entire release layer is the total value of the solid content of the binder component and the release agent.

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 other particles that form protrusions from the viewpoint of pinhole generation.

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

In the present invention, the thickness of the release layer may be set according to the purpose of use and is not particularly limited, but preferably, the weight of the release coating layer after curing is in the range of 0.01 to 1.5 μm. It is better, more preferably 0.05 to 1.3 μm, and even more preferably 0.1 to 1.1 μm. When the thickness of the release layer is 0.01 μm or more, peeling performance can be obtained, which is preferable. Further, when it is 1.5 μm or less, the curing time can be shortened, the flatness of the release film can be maintained, and the uneven thickness of the ceramic green sheet can be suppressed, which is preferable. Further, it is preferable that the thickness of the release layer is thin so that the curl becomes small when the release film is heated, so that the running performance is not deteriorated in the process of molding and drying the ceramic green sheet.

Surface free energy of the release layer surface of the release layer film of the present invention is preferably 18 mJ / ^{m 2} or more 40 mJ / ^{m 2} or less. More preferably, 23 mJ / ^{m 2} or more 35 mJ / ^{m 2} or less, further preferably 23 mJ / ^{m 2} or more 30 mJ / ^{m 2} or less. When it is 18 mJ / m ² or more, it is preferable that the ceramic slurry is not easily generated when the ceramic slurry is applied and can be applied uniformly. Further, when it is 40 mJ / m ² or less, there is no possibility that the releasability of the ceramic green sheet is deteriorated, which is preferable. Within the above range, it is possible to provide a release film having excellent releasability without repelling during coating.

The release film of the present invention preferably has a ceramic green sheet peeling force F (T25 / A90) of 0.5 mN / mm or more, more preferably 1.0 mN, at a peeling temperature of 25 ° C. and a peeling angle of 90 °. / Mm or more. When the peeling force F (T25 / A90) is 0.5 mN / mm or more, the peeling force is not too light and there is no possibility that the ceramic green sheet will be lifted during transportation, which is preferable. On the other hand, the peeling force F (T25 / A90) is preferably 4.5 mN / mm or less, more preferably 4.3 mN / mm or less. When the peeling force is 4.5 mN / mm or less, the ceramic green sheet is less likely to be damaged during peeling, which is preferable.

The release film of the present invention preferably has a ceramic green sheet peeling force F (T25 / A30) of 50.0 mN / mm or less at a peeling temperature of 25 ° C. and a peeling angle of 30 °, more preferably 45.0 mN / mm. It is mm or less. When the peeling force F (T25 / A30) is 50.0 mN / mm or less, the ceramic green sheet is less likely to be damaged during peeling when the peeling angle is low, which is preferable.

The release film of the present invention preferably has a ceramic green sheet peeling force F (T50 / A90) of 7.0 mN / mm or less, more preferably 6.0 mN / mm, at a peeling temperature of 50 ° C. and a peeling angle of 90 °. It is mm or less. When the peeling force F (T50 / A90) is 7.0 mN / mm or less, the ceramic green sheet is less likely to be damaged during peeling when the peeling temperature is high, which is preferable.

The release film of the present invention preferably has a ceramic green sheet peeling force F (T50 / A30) of 60.0 mN / mm or less at a peeling temperature of 50 ° C. and a peeling angle of 30 °, more preferably 45.0 mN / mm. It is mm or less. When the peeling force F (T50 / A30) is 60.0 mN / mm or less, the ceramic green sheet is less likely to be damaged during peeling when the peeling angle is low and the peeling temperature is high, which is preferable.

In the measurement of the peeling force in the present invention, a release film with a ceramic green sheet by the method described later is used as a sample for measuring the peeling force, and after static elimination, a peeling tester (VPA-3, manufactured by Kyowa Interface Science Co., Ltd.) is used. As shown in FIG. 1, the peeling was performed at a peeling angle of 90 ° or 30 ° C, a peeling temperature of 25 ° C. or 50 ° C., and a peeling speed of 10 m / min. As for the direction of peeling, a double-sided adhesive tape (Nitto Denko Co., Ltd., No. 535A) is attached on the SUS plate attached to the peeling tester, and the ceramic green sheet side is bonded to the double-sided tape on the release film. Was fixed and peeled off by pulling the release film side. The release film of the present invention has a low peeling force even at a peeling angle of 30 degrees, and is particularly suitable for producing an ultrathin layer ceramic green sheet.

In the present invention, in order to achieve the peeling force, the elastic modulus measured by the nanoindentation test on the surface of the release layer is preferably 2.0 GPa or more, preferably 2.3 GPa or more. Since the elastic modulus of the surface of the release layer is 2.0 GPa or more, the release layer is less likely to be deformed. Therefore, when the ceramic green sheet is peeled from the release layer, the release layer follows the ceramic green sheet. It becomes difficult, which is preferable because the ceramic green sheet can be normally peeled off with a light force. On the other hand, the upper limit of the film elastic modulus on the surface of the release coating layer is not particularly set, but it is preferably 10.0 GPa or less from the viewpoint of maintaining an appropriate adhesion between the release coating layer and the PET substrate. It is more preferably 0 GPa or less.

In the present invention, in order to achieve the peeling force, it is preferable that there is little erosion by the organic solvent. The erosion of the release layer can be confirmed by evaluating the difference in the surface state of the release layer before and after the release film is immersed in the organic solvent. As the organic solvent used for dipping, it is preferable to use toluene, which is used in a general ceramic slurry, assuming a ceramic green sheet manufacturing process. An example of a method for evaluating the surface state of the release layer is evaluation based on the contact angle, and it is preferable that the change in the contact angle on the surface of the release layer before and after immersion in toluene is small.

The type of droplet used when measuring the contact angle is not particularly limited, and water, bromonaphthalene, ethylene glycol, etc. can be preferably used, but the difference in the surface state of the release layer can be seen more prominently. It is most preferable to use diiodomethane which can be used.

When diiodomethane is used as a droplet used for measuring the contact angle, the diiodomethane contact angle θ _{1 on the surface of the release layer and the contact angle θ 2 on the} surface of the release layer after the release film is immersed in toluene at room temperature for 5 minutes. The smaller the absolute value of the difference (θ ₁ − θ ₂ ), the better the solvent resistance of the surface of the release layer, which is preferable. Specifically, the absolute value is preferably 3.0 ° or less, more preferably 2.0 ° or less, and most preferably 1.0 ° or less. When the temperature is 3.0 ° or less, erosion of the release layer due to the organic solvent during ceramic green sheet processing or internal electrode printing is suppressed, and there is no possibility that the peeling force is increased or the peeling uniformity is not impaired, which is preferable. The difference (θ ₁ − θ ₂ ) between the diiodomethane contact angle θ _{1 on the surface of the release layer and the contact angle θ 2} (θ 1 − θ 2) on the surface of the release layer after immersing the release film in toluene at room temperature for 5 minutes is most preferable. , The absolute value may be 0.05 ° or more.

In the present invention, in order to achieve the peeling force, the initial diiodomethane contact angle on the surface of the release layer is preferably 45.0 ° or more, more preferably 50.0 ° or more, and 55.0. Most preferably, it is greater than or equal to °. When the initial diiodomethane contact angle on the surface of the release layer is 45.0 ° or more, the release agent that reduces the release force is appropriately exposed on the surface of the release layer, so that the release force can be reduced, which is preferable. .. The initial diiodomethane contact angle on the surface of the release layer is preferably 100.0 ° or less, more preferably 90.0 ° or less, and most preferably 80.0 ° or less. When the initial diiodomethane contact angle on the surface of the release layer is 100.0 ° or less, the wettability does not deteriorate too much when the ceramic sheet is applied, and it is preferable that the diiodomethane can be applied uniformly.

In the present invention, the method for forming the release layer is not particularly limited, and a coating liquid in which a releaseable resin is dissolved or dispersed is developed by coating or the like on one surface of a polyester film of a base material, and a solvent or the like is formed. Is removed by drying, and then heat-dried and heat-cured.

In the present invention, when a thermosetting resin such as melamine is used as a binder for the release layer, the drying temperatures during solvent drying and heat curing are preferably 100 ° C. or higher and 180 ° C. or lower, preferably 110 ° C. or higher. It is more preferably 160 ° C. or lower, and most preferably 125 ° C. or higher and 150 ° C. or lower. The heating time is preferably 30 seconds or less, more preferably 20 seconds or less. When the temperature is 180 ° C. or lower, the flatness of the film is maintained and there is little risk of causing uneven thickness of the ceramic green sheet, which is preferable. When the temperature is 140 ° C. or lower, the film can be processed without impairing the flatness of the film, and the risk of causing uneven thickness of the ceramic green sheet is further reduced, which is particularly preferable. When the temperature is 100 ° C. or higher, the curing reaction of the thermosetting resin proceeds sufficiently, and the elastic modulus of the release layer is increased, which is preferable.

When an active energy ray-curable resin such as epoxy or acrylate is used as the binder for the release layer in the present invention, the drying temperature for solvent drying is preferably 50 ° C. or higher and 110 ° C. or lower, and 60 ° C. or higher and 100 ° C. or higher. More preferably, it is below ° C. The drying time is preferably 30 seconds or less, more preferably 20 seconds or less. Further, after the solvent is dried, the curing reaction is allowed to proceed by irradiating with active energy rays. As the active energy beam used at this time, ultraviolet rays, electron beams, X-rays and the like can be used, but ultraviolet rays are preferable because they are easy to use. The amount of ultraviolet rays to be irradiated ^{is preferably 30 to 300 mJ / cm 2} , more preferably 30 to 200 mJ / cm ² , and even more preferably 30 to 80 mJ / cm ^2. When the temperature is 30 mJ / cm ² or more, the curing of the resin progresses sufficiently, ^{and when the temperature is 300 mJ / cm 2} or less, the processing speed can be improved, so that a release film can be economically produced, which is preferable. ..

In the present invention, the surface tension of the coating liquid when the release layer is applied is not particularly limited, but is preferably 30 mN / m or less. By setting the surface tension as described above, the coatability after coating can be improved, and the unevenness of the coating film surface after drying can be reduced.

In the present invention, the coating liquid for applying the release coating layer is not particularly limited, but it is preferable to add a solvent having a boiling point of 90 ° C. or higher. By adding a solvent having a boiling point of 90 ° C. or higher, bumping during drying can be prevented, the coating film can be leveled, and the smoothness of the coating film surface after drying can be improved. The amount to be added is preferably about 10 to 80% by mass with respect to the entire coating liquid.

Any known coating method can be applied as the coating method, 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, or an air knife. Conventionally known methods such as the coating method can be used.

The surface of the release layer of the release film of the present invention is preferably flat so as not to cause defects in the ceramic green sheet coated and molded on it, and the region surface average roughness (Sa) is 7 nm or less. It is preferable to have. Further, it is more preferable that the Sa is satisfied and the maximum protrusion height (P) on the surface of the release layer is 100 nm or less. It is particularly preferable that the region surface average roughness (Sa) is 5 nm or less and the maximum protrusion height is 80 nm or less. When the region surface roughness is 7 nm or less and the maximum protrusion height is 100 nm or less, defects such as pinholes do not occur when the ceramic green sheet is formed, and the yield is good, which is preferable. It can be said that the smaller the region surface average roughness (Sa) is, the more preferable it is, but it may be 0.1 nm or more, or 0.3 nm or more. It can be said that the smaller the maximum protrusion height (P) is, the more preferable it is, but it may be 1 nm or more, or 3 nm or more.

In the present invention, in order to adjust the surface of the film on which the release coating layer is formed to a predetermined roughness range, it is preferable that the PET film does not substantially contain inorganic particles. The term "substantially free of inorganic particles" as used in the present invention means that both the base film and the release coating layer are 50 ppm or less when the elements derived from the particles are quantitatively analyzed by fluorescent X-ray analysis. It is defined as, preferably 10 ppm or less, and most preferably below the detection limit. This means that even if particles are not actively added to the base film, contamination components derived from foreign substances and stains attached to the raw material resin or the line or device in the film manufacturing process are peeled off and mixed in the film. This is because it may be done.

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

The release film for manufacturing a ceramic green sheet of the present invention is used for manufacturing such a multilayer ceramic capacitor. For example, it is manufactured as follows. First, the release film of the present invention is used as a carrier film, and a ceramic slurry for forming a ceramic element is applied and dried. The coated and dried ceramic green sheet preferably has a thickness of 0.2 μm to 1.0 μm. A conductive layer for forming the first or second internal electrode is printed on the coated and dried ceramic green sheet. A ceramic green sheet, a ceramic green sheet on which a conductive layer for forming a first internal electrode is printed, and a ceramic green sheet on which a conductive layer for forming a second internal electrode is printed are appropriately laminated and pressed. As a result, a mother laminate is obtained. The mother laminate is divided into a plurality of pieces to prepare a raw ceramic body. A ceramic body is obtained by firing a raw ceramic body. After that, the multilayer ceramic capacitor can be completed by forming the first and second external electrodes.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples. The characteristic values used in the present invention were evaluated using the following method.

(Surface roughness)
It is a value measured under the following conditions using a non-contact surface shape measurement system (VertScan R550H-M100). For the region surface average roughness (Sa), the average value of 5 measurements was adopted, and for the maximum protrusion height (P), the maximum value of 5 times excluding the maximum value and the minimum value was used after measuring 7 times.
(Measurement condition)
・ Measurement mode: WAVE mode ・ Objective lens: 10x ・ 0.5 × Tube lens ・ Measurement area 936μm × 702μm
(Analysis conditions)
・ Surface correction: 4th order correction ・ Interpolation processing: Complete interpolation

(How to make a release film with a ceramic green sheet)
The composition composed of the following materials was stirred and mixed, and dispersed for 60 minutes using a bead mill using zirconia beads having a diameter of 0.5 mm as a dispersoid to obtain a ceramic slurry.
Toluene 43.75 parts by mass Ethanol 43.75 parts by mass Barium titanate (HPBT-1 manufactured by Fuji Titanium Industry Co., Ltd.) 10.86 parts by mass Polyvinyl butyral (Eslek BM-S manufactured by Sekisui Chemical Co., Ltd.) 1.09 parts by mass DOP (phthalic acid) Dioctyl) 0.55 parts by mass Next, apply an applicator to the release surface of the obtained release film sample so that the dried slurry has a thickness of 1.0 μm, and dry at 90 ° C. for 2 minutes to obtain a ceramic green sheet. Was molded on a release film.

(Evaluation of ceramic green sheet peelability)
The release film with a ceramic green sheet prepared by the above method was cut into a width of 30 mm and a length of 80 mm to prepare a sample for measuring the peeling force. After static elimination using an electric removal machine (Keyence, SJ-F020), a peeling tester (VPA-3, Kyowa Interface Science Co., Ltd.) is used to remove the electricity at a peeling angle of 90 ° or 30 ° and a peeling temperature of 25 ° C or 50. The peeling was performed at a temperature of 1 ° C. and a peeling speed of 10 m / min. As for the direction of peeling, a double-sided adhesive tape (Nitto Denko Co., Ltd., No. 535A) is attached on the SUS plate attached to the peeling tester, and the ceramic green sheet side is bonded to the double-sided tape on the release film. Was fixed and peeled off by pulling the release film side. Among the obtained measured values, the average of the peeling force having a peeling distance of 20 mm to 70 mm was calculated, and the value was used as the peeling force. The measurement was carried out a total of 5 times, and the value of the average value of the peeling force was adopted and evaluated. Judgment was made based on the following criteria from the obtained numerical values of peeling force.
◯: 45.0 mN / mm or less Δ: Greater than 45.0 mN / mm, 60.0 mN / mm or less ×: Greater than 60.0 mN / mm The peeling angle in this evaluation method is fixed to the peeling tester. It refers to the angle in the direction in which the release film is pulled with respect to the evaluation sample axis. The peeling temperature is the temperature at which the release film fixed by using the heater type stage system attached to the device is heated. Using a handy type thermometer (manufactured by Anritsu Keiki Co., Ltd., HD-1400E), peeling is performed after confirming that the measurement sample has reached the corresponding temperature.

(Contact angle)
Diiodomethane (droplet amount) was used on the release surface of the release film that had been allowed to stand 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. A droplet of 0.9 μL) was prepared and the contact angle thereof was measured. As the contact angle, the contact angle 30 seconds after dropping on the release film was adopted, and the average value of the values measured 5 times was adopted.

(Contact angle after immersion in toluene)
The release film used for the measurement was cut into a size of 5 cm × 5 cm and immersed in a glass tray containing 30 mL of toluene at a liquid temperature of 25 ° C. for 5 minutes with the release side facing down. The soaked release film was taken out, air-dried for 15 minutes with the release surface facing up, and then vacuum-dried at 25 ° C. overnight. The release film obtained in this way after immersion in toluene was measured by the same method as the method for measuring the contact angle.

When the diiodomethane contact angle on the initial release layer surface before toluene immersion as measured by the above method is θ ₁ , and the diiodomethane contact angle on the release layer surface after toluene immersion is θ ₂ , θ ₁ − θ ₂ The absolute value was taken as the value of the change in contact angle before and after immersion in toluene. The initial contact angle and the change in contact angle were evaluated based on the following criteria.
(Evaluation of initial contact angle)
◯: 45.0 ° ≤ θ ₁
×: θ ₁ <45.0 °
(Evaluation of change in contact angle)
⊚: ｜ θ ₁ ― θ ₂ ｜ <1.0 °
◯: 1.0 ° ≤ ｜ θ ₁ ― θ ₂ ｜ <2.0 °
Δ: 2.0 ° ≦ ｜ θ ₁ ―θ ₂ ｜ ≦ 3.0 °
×: ｜ θ ₁ ― θ ₂ ｜ ＞ 3.0 °

(Evaluation of elastic modulus of release layer)
The release films obtained in Examples and Comparative Examples were cut into a size of 10 mm × 10 mm, and then the back surface of the cut release film base material was bonded with a two-component epoxy on a glass plate adhered to an aluminum pedestal. It was fixed with an agent. Then, using a micro-hardness evaluation device (ENT-3100 manufactured by Elionix Inc.), a nanoindentation test was performed in an atmosphere with a maximum indentation depth of 50 nm and 23 ° C., and the release layer of the release film was obtained. The elastic modulus of was measured. The results are shown in Table 2.

(Preparation of polyethylene terephthalate pellets (PET (I)))
As the esterification reaction device, a continuous esterification reaction device consisting of a stirrer, a splitter, a raw material charging port, and a three-stage complete mixing tank having a raw material charging port and a product outlet was used. TPA (terephthalic acid) was set to 2 tons / hour, EG (ethylene glycol) was set to 2 mol per 1 mol of TPA, antimony trioxide was set to an amount of 160 ppm of Sb atoms with respect to the PET produced, and these slurries were esterified. It was continuously supplied to the first esterification reaction can of the chemical reaction apparatus and reacted at normal pressure for an average residence time of 4 hours and 255 ° C. Next, the reaction product in the first esterification reaction can is continuously taken out of the system and supplied to the second esterification reaction can, and distilled off from the first esterification reaction can in the second esterification reaction can. EG is supplied in an amount of 8% by mass with respect to the produced PET, and an EG solution containing an amount of magnesium tetrahydrate having an amount of Mg atoms of 65 ppm with respect to the produced PET and 40 ppm of P atoms with respect to the produced PET. An EG solution containing an amount of TMPA (trimethyl phosphate) was added, and the reaction was carried out at normal pressure for an average residence time of 1 hour and 260 ° C. Next, the reaction product of the second esterification reaction can is continuously taken out of the system and supplied to the third esterification reaction can, and 39 MPa (400 kg / cm ² ) using a high-pressure disperser (manufactured by Nippon Seiki Co., Ltd.). 0.2 mass% of porous colloidal silica having an average particle size of 0.9 μm and 1 mass% of ammonium salt of polyacrylic acid attached per calcium carbonate after dispersion treatment with an average number of treatments of 5 passes under the pressure of 0.4% by mass of synthetic calcium carbonate having a diameter of 0.6 μm was added as an EG slurry of 10% each, and the reaction was carried out at normal pressure for an average residence time of 0.5 hours and at 260 ° C. The esterification reaction product produced in the third esterification reaction can was continuously supplied to a three-stage continuous polycondensation reaction apparatus to carry out polycondensation, and a stainless steel fiber having a 95% cut diameter of 20 μm was sintered. After filtering with a filter, it was subjected to ultracondensation, extruded into water, cooled, and then cut into chips to obtain PET chips with 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 pellets (PET (II)))
On the other hand, in the production of the PET (I) 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)).

(Manufacturing of laminated film X1)
After drying these PET chips, they were melted at 285 ° C., melted at 290 ° C. by a separate melt extruder extruder, and a filter obtained by sintering stainless steel fibers having a 95% cut diameter of 15 μm and a 95% cut diameter were obtained. Two-stage filtration of a filter obtained by sintering 15 μm stainless steel particles is performed and merged in the feed block, and PET (I) is surface layer B (extrusion type surface side layer) and PET (II) is surface. It is laminated so as to be layer A (separation surface side layer), extruded (casting) into a sheet at a speed of 45 m / min, and electrostatically adhered and cooled on a casting drum at 30 ° C. by the electrostatic adhesion method. An unstretched polyethylene terephthalate sheet having an intrinsic viscosity of 0.59 dl / g was obtained. The layer ratio was adjusted so that PET (I) / (II) = 60% by mass / 40% by mass in the discharge amount calculation of each extruder. Next, the unstretched sheet was heated with an infrared heater and then stretched 3.5 times in the vertical direction at a roll temperature of 80 ° C. due to the speed difference between the rolls. Then, it was guided to a tenter and stretched 4.2 times in the lateral direction at 140 ° C. Then, in the heat fixing zone, heat treatment was performed at 210 ° C. Then, a 2.3% relaxation treatment was carried out in the transverse direction at 170 ° C. to obtain a biaxially stretched polyethylene terephthalate film X1 having a thickness of 31 μm. The Sa of the surface layer A of the obtained film X1 was 2 nm, and the Sa of the surface layer B was 28 nm.

(Binder component)
The following materials were used as the binder component.
(A-1) Epoxy compound (alicyclic epoxy compound)
3', 4'-Epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate (Product name: Celoxide (registered trademark) 2021P, manufactured by Daicel Corporation, solid content 100% by mass)
(A-2) Epoxy compound (alicyclic epoxy compound)
Butanetetracarboxylic diantetra (3,4-epoxycyclohexylmethyl-modified ε-caprolactone (product name: Epolide (registered trademark) GT401, manufactured by Daicel Corporation, solid content 100% by mass)
(A-3) Epoxy compounds (alicyclic epoxy compounds)
Polyfunctional alicyclic epoxy group-containing polymer (Product name: EHPE (registered trademark) 3150, manufactured by Daicel Corporation, solid content 100% by mass)
(B-1) Acrylate compound (six-functional)
Dipentaerythritol hexaacrylate (Product name: A-DPH, manufactured by Shin-Nakamura Chemical Co., Ltd., solid content 100% by mass)
(B-2) Acrylate compound (10 functional)
10-functional urethane acrylate (Product name: Shikou (registered trademark) UV1700B, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., solid content 100% by mass)
(C-1) Melamine-based compound Hexamethoxymethylmelamine, solid content 100%, manufactured by Tokyo Chemical Industry Co., Ltd. (Product name N, N, N', N', N'', N''-hexakis (methoxymethyl) Melamine, molecular weight 390)
(C-2) Melamine-based compound Hexamethoxymethylmelamine, solid content 100%, manufactured by MT Aquapolymer Co., Ltd. (Product name: Cymel 303)

(Example 1)
A coating liquid 1 having the following composition is applied onto the surface layer A of the laminated film X1 using reverse gravure so that the thickness of the release layer after drying is 0.8 μm, dried at 90 ° C. for 15 seconds, and then 70 mJ. A release film for producing a ceramic green sheet was obtained by irradiating ultraviolet rays of / cm ^{2 with an ultraviolet irradiator (manufactured by Heleus, LC6B, H bulb).} When the ceramic slurry was applied to the obtained release film by the above method and the peeling force was evaluated, good evaluation results were obtained.
(Coating liquid 1)
Methyl ethyl ketone 43.70 parts by mass Toluene 43.70 parts by mass Binder component (A-1) 9.00 parts by mass (Product name: Celoxide (registered trademark) 2021P, manufactured by Daicel Co., Ltd., solid content 100% by mass))
Release agent 1.00 parts by mass (alicyclic epoxy group-containing silicone resin, UV POLY215, solid content 100%, manufactured by Arakawa Chemical Industries, Ltd.)
Photocation initiator 2.60 parts by mass (UV CATA211, active ingredient 19% by mass, manufactured by Arakawa Chemical Industry Co., Ltd.)

(Example 2)
A release film for producing a ceramic green sheet was obtained in the same manner as in Example 1 except that the composition was changed to the coating liquid 2 shown below.
(Coating liquid 2)
Methyl ethyl ketone 43.70 parts by mass Toluene 43.70 parts by mass Binder component (A-2) 9.00 parts by mass (Product name: Epolide (registered trademark) GT401, manufactured by Daicel, 100% solid content)
Release agent 1.00 parts by mass (alicyclic epoxy group-containing silicone resin, UV POLY215, solid content 100%, manufactured by Arakawa Chemical Industries, Ltd.)
Photocation initiator 2.60% by mass
(UV CATA211, active ingredient 19% by mass, manufactured by Arakawa Chemical Industry Co., Ltd.)

(Example 3)
A release film for producing a ceramic green sheet was obtained in the same manner as in Example 1 except that the composition was changed to the coating liquid 3 shown below.
(Coating liquid 3)
Methyl ethyl ketone 44.50 parts by mass Toluene 44.50 parts by mass Binder component (A-3) 9.00 parts by mass ((Product name: EHPE (registered trademark) 3150, manufactured by Daicel Co., Ltd., solid content 100% by mass)
Release agent 1.00 parts by mass (alicyclic epoxy group-containing silicone resin, UV POLY215, solid content 100%, manufactured by Arakawa Chemical Industries, Ltd.)
Photocation initiator 1.00% by mass (hexafluoroantimonate triarylsulfonium salt)
(Product name: CPI (registered trademark) 101A, active ingredient 50% by mass, manufactured by San-Apro)

(Example 4)
A release film for producing a ceramic green sheet was obtained in the same manner as in Example 1 except that the coating liquid 1 was changed to the coating liquid 4.
(Coating liquid 4)
Isopropyl alcohol 59.40 parts by mass Methyl ethyl ketone 19.80 parts by mass Binder component (B-1) 19.00 parts by mass (Dipentaerythritol hexaacrylate Product name: A-DPH, manufactured by Shin-Nakamura Chemical Industry Co., Ltd., solid content 100% by mass )
(Meta) Acryloyl group-containing copolymer silicone acrylic polymer 1.00 parts by mass (Product name: GL-04R, manufactured by Kyoeisha Chemical Co., Ltd., solid content 20%)
0.80 parts by mass of α-hydroxyalkylphenone (Product name: IRGACURE127, manufactured by BASF, 100% active ingredient)

(Example 5)
A release film for producing a ceramic green sheet was obtained in the same manner as in Example 1 except that the coating liquid 1 was changed to the coating liquid 5.
(Coating liquid 5)
Isopropyl alcohol 59.40 parts by mass Methyl ethyl ketone 19.80 parts by mass Binder component (B-2) 19.00 parts by mass (10-functional urethane acrylate acrylate Product name: Shikou (registered trademark) UV1700B, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., solid content 100% by mass)
(Meta) Acryloyl group-containing copolymer silicone acrylic polymer 1.00 parts by mass (Product name: GL-04R, manufactured by Kyoeisha Chemical Co., Ltd., solid content 20%)
0.80 parts by mass of α-hydroxyalkylphenone (Product name: IRGACURE127, manufactured by BASF, 100% active ingredient)

(Example 6)
A coating liquid 6 having the following composition is applied onto the surface layer A of the laminated film X1 using reverse gravure so that the thickness of the release layer after drying is 0.6 μm, and dried at 140 ° C. for 15 seconds. A release film for manufacturing a ceramic green sheet was obtained.
(Coating liquid 6)
Methyl ethyl ketone 44.50 parts by mass Toluene 44.50 parts by mass Binder (C-1) 10.00 parts by mass (hexamethoxymethylmelamine, solid content 100%, manufactured by Tokyo Chemical Industry Co., Ltd., trade name N, N, N', N ', N'', N''-hexakis (methoxymethyl) melamine, molecular weight 390))
Release agent 0.50 parts by mass (one-ended carboxyl-modified polydimethylsiloxane, X22-3710, solid content 100%, manufactured by Shin-Etsu Chemical Industry Co., Ltd., alkyl group intervenes between dimethylsiloxane and carboxyl group)
Acid catalyst (p-toluenesulfonic acid) 0.50 parts by mass

(Example 7)
A release film for producing a ceramic green sheet was obtained in the same manner as in Example 6 except that the amount of the release agent (X22-3710) added to the coating liquid 6 of Example 6 was changed to 0.20 parts by mass.

(Example 8)
The same as in Example 6 except that the amount of hexamethoxymethylmelamine added to the coating liquid 6 of Example 6 was changed to 9.0 parts by mass and the amount of the release agent (X22-3710) added was changed to 1.0 part by mass. Obtained a release film for manufacturing a ceramic green sheet.

(Example 9)
The same as in Example 6 except that the amount of hexamethoxymethylmelamine added to the coating liquid 6 of Example 6 was changed to 8.0 parts by mass and the amount of the release agent (X22-3710) added was changed to 2.0 parts by mass. Obtained a release film for manufacturing a ceramic green sheet.

(Examples 10 to 12)
A release film for producing a ceramic green sheet was obtained in the same manner as in Example 6 except that the film thickness of the release layer of Example 6 was changed to the film thickness shown in Table 2.

(Comparative Example 1)
A release film for producing a ceramic green sheet was obtained in the same manner as in Example 1 except that the coating liquid 1 was changed to the coating liquid 7. In Comparative Example 1, since a polyether-modified silicone that does not interact with the epoxy binder component was used, the solvent resistance of the surface of the release layer was deteriorated, and the peeling force at a low angle and high temperature was remarkably increased.
(Coating liquid 7)
Methyl ethyl ketone 43.70 parts by mass Toluene 43.70 parts by mass Binder component (A-1) 9.00 parts by mass (Product name: Celoxide (registered trademark) 2021P, manufactured by Daicel Co., Ltd., solid content 100% by mass))
Release agent 1.00 parts by mass (polyether-modified silicone resin, BYK-302, solid content 100%, manufactured by Arakawa Chemical Industries, Ltd.)
Photocation initiator 2.60 parts by mass (UV CATA211, active ingredient 19% by mass, manufactured by Arakawa Chemical Industry Co., Ltd.)

(Comparative Example 2)
A release film for producing a ceramic green sheet was obtained in the same manner as in Example 1 except that the coating liquid 1 was changed to the coating liquid 8. In Comparative Example 2, since a mold release agent having polydimethylsiloxane as the main chain was used and surface hardening was inhibited by oxygen peculiar to radical polymerization, the solvent resistance near the surface of the mold release layer was deteriorated. .. As a result, although the elastic modulus of the release layer is high, the solvent resistance of the surface of the release layer is poor, so that the peeling force at a low angle and high temperature is remarkably high.
(Coating liquid 8)
Isopropyl alcohol 60.00 parts by mass Methyl ethyl ketone 20.00 parts by mass Binder component (B-1) 19.00 parts by mass (Dipentaerythritol hexaacrylate Product name: A-DPH, manufactured by Shin-Nakamura Chemical Industry Co., Ltd., solid content 100% by mass )
0.20 parts by mass of acryloyl group-containing polyether-modified polydimethylsiloxane (product name: BYK-UV3500, manufactured by Big Chemie Japan, 100% solid content)
0.80 parts by mass of α-hydroxyalkylphenone (Product name: IRGACURE127, manufactured by BASF, 100% active ingredient)

(Comparative Example 3)
A release film for manufacturing a ceramic sheet was obtained in the same manner as in Example 6 except that the coating liquid 6 was changed to the coating liquid 9 below. In Comparative Example 3 in which a large amount of release agent is added and the melamine resin is only 70% by mass of the release layer, the elastic modulus of the release layer is low and the solvent resistance of the release layer surface is also poor. Has grown. In particular, the peeling force at low angles and high temperatures was significantly increased.
(Coating liquid 9)
Methyl ethyl ketone 44.80 parts by mass Toluene 44.80 parts by mass Binder (C-1) 7.00 parts by mass (hexamethoxymethylmelamine, solid content 100%, manufactured by Tokyo Chemical Industry Co., Ltd.)
Release agent 3.00 parts by mass (one-ended carboxyl-modified polydimethylsiloxane, X22-3710, solid content 100%, manufactured by Shin-Etsu Chemical Co., Ltd.)
Acid catalyst (p-toluenesulfonic acid) 0.40 parts by mass

(Comparative Example 4)
A release film for manufacturing a ceramic sheet was obtained in the same manner as in Example 1 except that the coating liquid 1 was changed to the coating liquid 10 below. The interaction between the hydroxyl group of the release agent and the melamine resin is strong, and probably because the release agent is not exposed on the surface, the elastic modulus of the release layer is high and the solvent resistance of the release layer surface is also high, but the release force is high. Has become higher.
(Coating liquid 10)
Methyl ethyl ketone 44.75 parts by mass Toluene 44.75 parts by mass Binder (C-2) 9.00 parts by mass (hexamethoxymethylmelamine, solid content 100%, manufactured by MT Aquapolymer, trade name Cymel 303)
Release agent 1.00 parts by mass (polyester-modified OH group-containing polydimethylsiloxane, BYK-370, solid content 25%, manufactured by Big Chemie Japan)
Acid catalyst (paratoluenesulfonic acid) 0.50 parts by mass

The evaluation results of each Example and Comparative Example are shown in Tables 1 and 2.

In Examples 1 to 12, since the peeling force at a peeling angle of 30 ° and a peeling temperature of 50 ° C. was low, the ceramic sheet could be peeled without damaging it, and a high-quality ceramic capacitor could be obtained. In Comparative Examples 1 to 4, since the peeling force was high at a peeling angle of 30 ° and a peeling temperature of 50 ° C., the ceramic sheet was damaged and the yield of the ceramic capacitor was deteriorated.

According to the present invention, when the peeling temperature between the ceramic green sheet and the release film is high, the peeling force is low even when the peeling angle is low, and damage to the ceramic green sheet can be suppressed. Sheets can be manufactured.

1: SUS plate 2: Double-sided adhesive tape 3: Ceramic green sheet 4: Release layer 5: Polyester film base material 6: Pulling direction 7: Peeling angle 8: Release film 9: Release film with ceramic green sheet

Claims (10)

A polyester film is used as a base material, and the base material has a surface layer A having substantially no inorganic particles on at least one side thereof.
A release film in which a release layer is laminated directly on the surface of the surface layer A on at least one surface or via another layer.
When the ceramic green sheet is molded on the release layer, the peeling temperature between the ceramic green sheet and the release film is 50 ° C.
The peeling force F (T50 / A 90 ) at a peeling angle of 90 ° is 7.0 mN / mm or less.
The polyester film base material has a surface layer B on a surface opposite to the surface layer A.
The region surface average roughness (Sa) of the surface layer A is smaller than the region surface average roughness (Sa) of the surface layer B.
A release film for manufacturing ceramic green sheets. The ceramic green sheet production according to claim 1, wherein the film elastic modulus measured from the surface of the release layer opposite to the base material by the nanoindentation test on the release layer is 2.0 GPa or more. Release film for use. The ceramic green sheet according to claim 1 or 2, wherein the release layer is formed by curing a coating film containing at least a release agent and a binder component, and the binder component is 85% by mass or more of the solid content of the release layer. Release film for manufacturing. The release film for producing a ceramic green sheet according to claim 3, wherein the release agent contains a silicone skeleton, and the content of the release agent is 15% by mass or less with respect to the solid content of the release layer. The release film for producing a ceramic green sheet according to any one of claims 1 to 4, wherein the release layer has a film thickness of 0.01 μm to 1.5 μm. The release film for producing a ceramic green sheet according to any one of claims 3 to 5, wherein the binder component is at least one crosslinked product of a melamine compound, an epoxy compound, and an acrylate compound. The surface layer B forming the surface layer opposite to the surface layer A of the polyester film base material contains particles, the particles are silica particles and / or calcium carbonate particles, and the total of the particles is the surface layer B. The release film for producing a ceramic green sheet according to any one of claims 1 to 6, which contains 5000 to 15000 ppm. The region surface average roughness (Sa) of the surface layer A is 0.1 nm or more and 7 nm or less, and the region surface average roughness (Sa) of the film of the surface layer B is 1 to 40 nm. A release film for manufacturing a ceramic green sheet according to any one. A method for producing a ceramic green sheet by molding a ceramic green sheet using the release film for producing a ceramic green sheet according to any one of claims 1 to 8, wherein the molded ceramic green sheet is 0.2 μm to 1 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 9.

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