JP7343021B2 - Release film for ceramic green sheet production - Google Patents

Description

The present invention relates to a release film for manufacturing ceramic green sheets, and more specifically, when manufacturing ultra-thin ceramic green sheets, the peeling between the ceramic green sheet and the release film is high, even when the peeling angle is low. The present invention relates to a release film for producing ultra-thin ceramic green sheets that has low force and can suppress damage to ceramic green sheets.

Conventionally, a release film having a polyester film as a base material and a release layer laminated thereon has been used for molding ceramic green sheets such as multilayer ceramic capacitors and ceramic substrates. In recent years, as multilayer ceramic capacitors have become smaller and larger in capacity, the thickness of ceramic green sheets has also tended to become thinner. Ceramic green sheets are formed by coating a release film with a slurry containing a ceramic component such as barium titanate and a binder resin, and drying the slurry. After printing electrodes on the molded ceramic green sheets and peeling them off from the release film, the ceramic green sheets are laminated, pressed, fired, and coated with external electrodes to produce a multilayer ceramic capacitor. When molding a ceramic green sheet on the surface of a mold release layer of a polyester film, there is a problem that minute protrusions on the surface of the mold release layer affect the molded ceramic green sheet, making it more likely to cause defects such as repellency and pinholes. there were. Therefore, various methods have been developed to realize a release layer surface having excellent flatness (for example, Patent Document 1).

However, in recent years, ceramic green sheets have become even thinner, and ceramic green sheets with a thickness of 1.0 μm or less, more specifically, 0.2 μm to 1.0 μm, are now required. As a result, the strength of the ceramic green sheet decreases, and it has become necessary not only to smooth the surface of the release layer, but also to apply a low and uniform peeling force when peeling the ceramic green sheet from the release film. . In other words, it is becoming more important to reduce the force applied to the ceramic green sheet as much as possible when peeling the ceramic green sheet from the release film so as not to damage the ceramic green sheet.

As a method for peeling a ceramic green sheet, a method has been proposed in which the ceramic green sheet side is fixed to a suction head and a release film, which is a carrier film, is peeled from the end (for example, Patent Document 2). In the case of Patent Document 2, it can be seen from the dimensions of the device that the peeling angle is as low as about 3°. It is generally known that when the peeling angle is lower than 90°, the peeling force becomes heavier (for example, Non-Patent Document 1). Further, the head that peels the ceramic sheet from the release film and the head that laminates the ceramic sheet 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 sheets together during lamination.

In recent years, it has been discovered that the surface of the release layer can be made smooth by using an ultraviolet curable resin. Furthermore, it has been found that the silicone component contained in the release layer or its cured product also provides excellent releasability from the ceramic sheet (for example, see Patent Document 3).

However, according to the method described in Patent Document 3, silicone components tend to segregate on the surface of the mold release layer during processing of the mold release layer, and surface hardening inhibition peculiar to radical polymerization occurs. There was a problem in that the solvent properties deteriorated. If the solvent resistance near the surface of the mold release layer is poor, the surface of the mold release layer will be eroded by organic solvents, such as toluene, used during ceramic green sheet processing and internal electrode printing. There was a problem in that the peeling force during peeling increased significantly, causing damage to the ceramic sheet. Based on the above, we focused on the fact that a release layer that has low peeling force at low angles and low peeling force even when peeling at high temperatures is effective in reducing damage to ceramic green sheets, and we have developed the present invention. Ta.

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

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

As a result of intensive studies in view of the above circumstances, the present invention has been developed to maintain high smoothness of the surface of the release layer of the release film in order to prevent damage to the ceramic green sheet, and to improve the performance of the conventional ceramic green sheet manufacturing method. Compared to release films, ceramic green has a lower peeling force even when the peeling angle is low during the production of ceramic green sheets, and has a lower peeling force when peeling even when producing ultra-thin ceramic green sheets with a thickness of 1 μm or less. The present invention aims to provide a release film for sheet production.

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

That is, the present invention has the following configuration.
1. A polyester film is used as a base material, the base material has a surface layer A substantially free of inorganic particles on at least one side, and the surface layer A on at least one side is directly or separately separated through another layer. A release film in which a mold layer is laminated, and when a ceramic green sheet is molded on the release layer, the peeling force F between the ceramic green sheet and the release film at a peeling temperature of 50°C and a peeling angle of 30° is A release film for producing ceramic green sheets with (T50/A30) of 60 mN/mm or less.
2. The ceramic green sheet production according to the above-mentioned item 1, wherein the coating elastic modulus measured from the surface of the release layer opposite to the base material by a nanoindentation test on the release layer is 2.0 GPa or more. Release film for use.
3. The release layer is formed by curing a coating film containing at least a release agent and a binder component, and the ceramic green according to the first or second item above, wherein the binder component accounts for 85% by mass or more of the solid content of the release layer. Release film for sheet manufacturing.
4. 3. The release film for producing a ceramic green sheet according to the above 3, wherein the release agent contains a silicone skeleton, and the content of the release agent is 15% by mass or less based on 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 aspects, wherein the release layer has a 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 aspects, wherein the binder component comprises a crosslinked product of at least one of a melamine compound, an epoxy compound, and an acrylate compound.
7. The surface layer B forming the surface layer on the opposite side 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 number of particles is the surface layer B. The release film for producing a ceramic green sheet according to any one of the first to sixth aspects, wherein the release film contains 5,000 to 15,000 ppm.
8. A method for manufacturing a ceramic green sheet, comprising molding a ceramic green sheet using the release film for manufacturing a ceramic green sheet according to any one of the first to seventh aspects, wherein the molded ceramic green sheet has a thickness of 0.2 μm to 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 aspect.

The release film for ceramic green sheet production of the present invention has a smooth surface of the release layer, and can be used when the peeling angle is low during ceramic green sheet production compared to conventional release films for ceramic green sheet production. It also has low peeling force, suppresses damage to ceramic green sheets, and can produce ultra-thin ceramic green sheets with a thickness of 0.2 to 1.0 μm.

FIG. 3 is a schematic diagram for explaining a method for measuring peeling force in the present invention.

The present invention will be explained in detail below.

The release film for producing ceramic green sheets of the present invention has a surface layer A containing substantially no inorganic particles on at least one side of a polyester film, and has a surface layer A containing substantially no inorganic particles on at least one side. A release layer is laminated through the layers, and the release force F (T50/A30) between the ceramic sheet coated on the release layer and the release layer at a peeling temperature of 50°C and a peeling angle of 30° is 60mN. /mm or less is preferable.

(Polyester film)
The polyester constituting the polyester film used as the base material in the present invention is not particularly limited, and a film formed from a polyester commonly used as a base material for a release film can be used, but preferably, It is preferable to use a crystalline linear saturated polyester consisting of an aromatic dibasic acid component and a diol component. Copolymers based on the constituents are further preferred, particularly polyester films formed from polyethylene terephthalate. In polyethylene terephthalate, the repeating unit of ethylene terephthalate is preferably 90 mol% or more, more preferably 95 mol% or more, and a small amount of other dicarboxylic acid component or diol component may be copolymerized, but from the viewpoint of cost. , those made from only terephthalic acid and ethylene glycol are preferred. Further, known additives such as antioxidants, light stabilizers, ultraviolet absorbers, crystallizing agents, etc. may be added within a range that does not impede the effects of the film of the present invention. The polyester film is preferably a biaxially oriented polyester film for reasons such as high elastic modulus in both directions.

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 during the stretching process. On the other hand, if it is 0.70 dl/g or less, it is preferable because the cutting properties are good when cutting into a predetermined product width and dimensional defects do not occur. Further, it is preferable that the raw material pellets be sufficiently vacuum dried.

The method for producing the polyester film in the present invention is not particularly limited, and any conventionally commonly used method can be used. For example, it can be obtained by melting the polyester in an extruder, extruding it into a film, cooling it in a rotating cooling drum to obtain an unstretched film, and then biaxially stretching the unstretched film. A biaxially stretched film can be obtained by sequentially biaxially stretching a uniaxially stretched film in the longitudinal or transverse direction in the transverse or longitudinal direction, or by simultaneously biaxially stretching an unstretched film in the longitudinal and transverse directions. I can do it.

In the present invention, the stretching temperature during stretching of the polyester film is preferably higher than the secondary transition point (Tg) of the polyester. It is preferable to stretch the film 1 to 8 times, particularly 2 to 6 times, in both the longitudinal and transverse directions.

The thickness of the polyester film is preferably 12 to 50 μm, more preferably 15 to 38 μm, and even more preferably 19 to 33 μm. If the thickness of the film is 12 μm or more, it is preferable because there is no risk of deformation due to heat during film production, processing of a release layer, and molding of ceramic green sheets. On the other hand, if the thickness of the film is 50 μm or less, the amount of film to be discarded after use will not be excessively large, which is preferable in terms of reducing environmental burden.

The above-mentioned polyester film base material may be a single layer or a multilayer of two or more layers, but it is preferable to have a surface layer A substantially free of inorganic particles on at least one side. 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, which can contain particles, on the opposite side of the surface layer A, which does not substantially contain inorganic particles. Assuming that the layer on which the release layer is applied is the surface layer A, the layer on the opposite side is the surface layer B, and the other core layer is layer C, the layer structure in the thickness direction is the release layer/ Examples include laminated structures such as A/B or release layer/A/C/B. Naturally, the layer C may have a plurality of layers. Further, the surface layer B may not contain particles. In that case, it is preferable to provide a coating layer containing particles and a binder on the surface layer B in order to provide slipperiness for winding the film into a roll.

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 area surface average roughness (Sa) of the surface layer A is preferably 7 nm or less. When Sa is 7 nm or less, pinholes are less likely to occur during molding of ultra-thin ceramic green sheets to be laminated, which is preferable. It can be said that the smaller the area 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 below is provided on the surface layer A, it is preferable that the coat layer does not substantially contain inorganic particles, and the area surface average roughness (Sa) after lamination of the coat layer is within the above range. It is preferable to enter. In the present invention, "substantially free of inorganic particles" means a content that is 50 ppm or less, preferably 10 ppm or less, most preferably below the detection limit when inorganic elements are quantified by fluorescent X-ray analysis. do. This is because even if inorganic particles are not actively added to the film, contaminants derived from foreign substances and dirt attached to the raw resin or the lines and equipment in the film manufacturing process can peel off and get 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 side to the side to which the release layer is applied preferably contains particles, particularly from the viewpoint of the slipperiness of the film and the ease with which air can escape. Preferably, silica particles and/or calcium carbonate particles are used. The total amount of particles contained in the surface layer B is preferably 5,000 to 15,000 ppm. At this time, the area surface average roughness (Sa) of the film of the surface layer B is preferably in the range of 1 to 40 nm. More preferably, the range is 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, resulting in a good rolled shape and good flatness. , it is suitable for producing ultra-thin ceramic green sheets. In addition, 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 are not formed, resulting in stable quality when producing ultra-thin ceramic green sheets. It is preferable.

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

The average particle diameter of the particles added to the surface layer B is preferably 0.1 μm or more and 2.0 μm or less, particularly preferably 0.5 μm or more and 1.0 μm or less. It is preferable that the average particle diameter of the particles is 0.1 μm or more because the release film has good slip properties. Further, it is preferable that the average particle diameter is 2.0 μm or less, since there is no fear that pinholes will be generated in the ceramic green sheet due to coarse particles on the surface of the release layer.

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

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

When the surface layer B does not contain particles, it is preferable that a coating layer containing particles be provided on the surface layer B to provide slipperiness. This coat layer is not particularly limited, but is preferably provided as an in-line coat applied during the production 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 roughness in the area for the same reason as the area average roughness (Sa) of the surface layer B described above. It is preferable that the surface average roughness (Sa) is in the range of 1 to 40 nm. More preferably, the range is 5 to 35 nm.

From the viewpoint of reducing pinholes, it is preferable not to use recycled raw materials 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 lubricants from being mixed in.

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 layer thickness of the base film. If it is 20% or more, it is difficult to be influenced by particles contained in the surface layer B etc. from inside the film, and it is easy for the area surface average roughness Sa to satisfy the above range, which is preferable. When the thickness is 50% or less of the total thickness of the base film, the ratio of recycled raw materials used in the surface layer B can be increased, and the environmental load is reduced, which is preferable.

Furthermore, from the viewpoint of economic efficiency, 50 to 90% by mass of film scraps or recycled raw materials from PET bottles can be used for 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 lubricant contained in the surface layer B, the particle size, and the area surface average roughness (Sa) satisfy the above ranges.

In addition, in order to improve the adhesion of a release layer to be applied later or to prevent static electricity, a film may be applied to the surface of surface layer A and/or surface layer B before or after uniaxial stretching during the film forming process. A coating layer may be provided on the substrate, and 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 crosslinking density. Increasing the crosslinking density also improves the elastic modulus, so by reducing deformation during peeling, it is possible to lower the peeling force at high temperatures and at low angles. It is also preferable that the surface of the release layer has high solvent resistance in order to reduce the peeling force at high temperatures and at low angles. The high solvent resistance of the surface of the mold release layer prevents erosion of the surface of the mold release layer by solvents during slurry coating. By reducing the deformation of the surface of the release layer due to solvent erosion, the peeling force can be lowered. In addition, it is preferable that the release agent in the release layer is moderately segregated on the surface while maintaining interaction with the binder, in order to reduce the peeling force at high temperatures and at low angles.

The binder component contained in the release layer in the present invention is not particularly limited, but in order to increase the crosslinking density of the release layer, it is preferable that a component that can be crosslinked is crosslinked. As the binder component, thermosetting resin, ultraviolet curing resin, etc. can be used. The release agent, binder component, etc. that are constituent substances in the coating solution and coating before crosslinking and curing may change chemically in the release layer after crosslinking and curing. Since it is difficult to describe the chemical structure itself in the crosslinked and cured state, the release layer is expressed as a cured coating film containing at least a release agent and a binder component.

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

Suitable binder components for the thermosetting resin include melamine compounds. It is preferable to use a melamine compound because it is possible to obtain a release layer with a high crosslinking density.

(Melamine compound)
The melamine resin used for the release layer in the present invention is not particularly limited and can be any commonly used melamine resin, but it is obtained by condensing melamine and formaldehyde, and contains a triazine ring, a methylol group, and/or an alkoxy group in one molecule. It is preferable that each of them has one or more methyl groups. Specifically, a compound obtained by subjecting a methylolmelamine derivative obtained by condensing melamine and formaldehyde to a dehydration condensation reaction with a lower alcohol such as methyl alcohol, ethyl alcohol, isopropyl alcohol, butyl alcohol, etc. to etherify it is preferable. Examples of methylolated melamine derivatives include monomethylolmelamine, dimethylolmelamine, trimethylolmelamine, tetramethylolmelamine, pentamethylolmelamine, and hexamethylolmelamine. One type or two or more types may be used.

The release layer in the present invention preferably has a high crosslinking density and a high modulus of elasticity in order to reduce the peeling force. Therefore, as the melamine resin used for the release layer, it is preferable to use hexamethylolmelamine, which has many crosslinking points in one molecule and can increase the crosslinking density of the release layer.

When using an ether compound obtained by dehydration condensation reaction of a methylol melamine derivative with alcohol as the melamine resin used in the release layer in the present invention, from the viewpoint of reactivity, it is preferable to use a hexamethoxy resin obtained by dehydration condensation reaction with methyl alcohol. Particularly preferred is methylmelamine.

In the melamine resin used for the release layer in the present invention, it is preferable that the weight average molecular weight is less than 1000. More preferably, the weight average molecular weight is less than 800, and even more preferably less than 600. It is preferable that the weight average molecular weight is less than 1,000 because the crosslinking reaction progresses easily and a film with higher crosslinking density can be formed. Note that the weight average molecular weight in this specification is a value measured by gel permeation chromatography (GPC) in terms of standard polystyrene.

When using a melamine compound as a binder for the release layer in the present invention, it is preferable to add a catalyst to promote the crosslinking reaction of the melamine compound. The catalyst to be used is not particularly limited, but existing acid catalysts can be used, and carboxylic acid-based, metal salt-based, phosphoric ester-based, and sulfonic acid-based catalysts can be suitably used. Moreover, a block type catalyst in which the acid site is blocked can also be used.

When using a sulfonic acid type acid catalyst, for example, p-toluenesulfonic acid, xylenesulfonic acid, cumenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, trifluoromethanesulfonic acid, etc. are preferably used. can be used, and para-toluenesulfonic acid can be particularly preferably used.

When using a carboxylic acid type acid catalyst, for example, benzoic acid, acetic acid, formic acid, oxalic acid, propionic acid, or derivatives thereof can be used. Although carboxylic acid catalysts are known to have weaker acidity and inferior reactivity than other catalysts such as sulfonic acid catalysts, carboxylic acid catalysts can also be used satisfactorily in the present invention. In addition, since carboxylic acid type reacts slower than sulfonic acid type, the mold release agent tends to segregate on the surface during the drying process, so it is possible to achieve mold release effects with the addition of a smaller amount of mold release agent. Therefore, it is preferable. In particular, 4-methylbenzoic acid is inexpensive, readily available, and easy to use.

The amount of the acid catalyst added is preferably 0.1 to 10% by mass based on the melamine 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 the content is 0.1% by mass or more, the curing reaction progresses easily, which is preferable. On the other hand, if the content is 10% by mass or less, there is no risk of the acid catalyst transferring to the ceramic green sheet to be molded, which is preferable since there is no risk of adverse effects.

Suitable binder components for the ultraviolet curable resin include cationic curable resins and radical curable resins. Examples of cationic curing resins include epoxy compounds, ether compounds, and oxetane compounds. Furthermore, as the radical curing resin, acrylate compounds can be suitably used. In the case of a cationic curing resin, the epoxy compound has high reactivity and is therefore preferable.

(Epoxy compound)
Examples of the compound containing an epoxy group used in the release layer in the present invention include glycidyl ether type, glycidyl amine type, glycidyl ester type epoxy, and alicyclic epoxy. In particular, glycidyl ether type epoxy and alicyclic epoxy are preferred, and from the viewpoint of reactivity, it is most preferred to use alicyclic epoxy. Examples of glycidyl ether type epoxy compounds include aromatic glycidyl ethers represented by bisphenol type epoxy resins and cresol novolac type epoxy resins, and aliphatic glycidyl ethers represented by hydrogenated A-type glycidyl ethers and butyl glycidyl ethers. It will be done. Examples of the alicyclic epoxy include those having an ester skeleton, dicyclopentadiene skeleton, fluorene skeleton, ε-caprolactone skeleton, etc., and may have skeletons other than these.

As the alicyclic epoxy compound, commercially available ones can also be used. Examples of commercially available products include Cyclomer (registered trademark) M100, Celoxide (registered trademark) 2000 (all manufactured by Daicel, monofunctional), Celoxide (registered trademark) 2021P, 2081 (all manufactured by Daicel, bifunctional) , Epolead (registered trademark) GT401 (manufactured by Daicel Corporation, tetrafunctional), and EHPE (registered trademark) 3150 (manufactured by Daicel Corporation, multifunctional).

The epoxy compounds used in the release layer in the present invention may be used alone or in combination of two or more. Among these epoxy group-containing compounds, alicyclic epoxy compounds are particularly preferred, and polyfunctional alicyclic epoxy resins having two or more functionalities in one molecule are more preferred.

(Cationic polymerization initiator)
When using a cationic curing resin for the release layer in the present invention, it is preferable to use a cationic polymerization initiator. Examples of cationic polymerization initiators include onium salts such as aryldiazonium salts, aryliodonium salts, arylhalonium salts, and arylsulfonium salts, and organometallic complexes such as iron-arene complexes, titanocene complexes, and arylsilanol-aluminum complexes. 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 Co., Ltd.), SP-150, SP-152, SP-170, SP-172 (manufactured by Asahi Denka Kogyo Co., Ltd.) ), Uvacure (registered trademark) 1590, 1591 (manufactured by Daicel UCB), Sunaid (registered trademark) SI-110, SI-180, SI-100L, SI-80L, SI60L (manufactured by Sanshin Kagaku), 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 based on the cationic curing resin used.

When using a photocationic polymerization initiator as a cationic polymerization initiator, it is desirable to use it together with a photosensitizer. Examples of the photosensitizer include carbonyl compounds, organic sulfur compounds, persulfates, redox compounds, azo and diazo compounds, halogen compounds, photoreducible dyes, and the like. Specific photosensitizers include, for example, benzoin methyl ether, benzoin isopropyl ether, benzoin derivatives such as α,α-dimethoxy-α-phenylacetophenone, benzophenone, 2,4-dichlorobenzophenone, and o-benzoylbenzoic acid. Methyl, 4,4'-bis(dimethylamino)benzophenone, benzophenone derivatives such as 4,4'-bis(dimethylamino)benzophenone, thioxanthone derivatives such as 2-chlorothioxanthone, 2-isopropylthioxanthone, 2-chloroanthraquinone , anthraquinone derivatives such as 2-methylanthraquinone, acridone derivatives such as N-methylacridone and N-butylacridone, α,α-diethoxyacetophenone, benzyl, fluorenone, xanthone, uranyl compounds, halogen compounds, etc. It will 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 based on the cationic curable resin.

(acrylate compound)
The acrylate compound used in the release layer in the present invention is preferably a (meth)acrylate compound that is an ultraviolet curable resin. Since the (meth)acrylate compound has a very fast reaction rate, the radical polymerization reaction proceeds instantaneously at the same time as the photopolymerization initiator is cleaved, making it possible to form a coating film with high crosslinking density and high elastic modulus. Increasing the modulus of elasticity of the release layer is preferable because the release layer will not deform and follow the release layer when it is peeled off, and there will be no risk of damaging the ceramic green sheet. Note that the (meth)acrylate-based compounds referred to herein refer to a group of compounds in which the methacryloyl group and acrylolyl group contained in the molecule serve as crosslinking points and a radical curing reaction proceeds.

Examples of (meth)acrylate compounds include acrylate, methacrylate, and urethane acrylate. Although each can be suitably used, it is more preferable to use urethane acrylate. When using urethane acrylate, the urethane bonds within the molecule can form hydrogen bonds, so the strength of the cured coating film can be further increased. Hereinafter, the term urethane acrylate will be used as a term that includes urethane methacrylate.

The number of functional groups in one molecule of the (meth)acrylate compound (the number of functional groups that can become crosslinking points in a radical curing reaction) is preferably 4 or more from the viewpoint of increasing the crosslinking density, and 6 or more. It is more preferable that there be one, more preferably seven or more, even more preferably nine or more. Although there is no particular upper limit to the number of functional groups, it is preferably 20 or less. When it is 20 or less, the intramolecular reaction proceeds more easily than the intermolecular crosslinking reaction, and there is no possibility that the effect of improving the crosslinking density will not be obtained, which is preferable.

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

When using a monomer as a (meth)acrylate compound, for example, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, Examples include pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethoxylated isocyanuric acid tri(meth)acrylate, caprolactone-modified dipentaerythritol hexa(meth)acrylate, etc. .

When using an oligomer as the (meth)acrylate compound, for example, a polyfunctional (meth)acrylate oligomer, a polyester acrylate oligomer, an epoxy acrylate oligomer, a polyether acrylate oligomer, a polybutadiene acrylate oligomer, a silicone acrylate oligomer, etc. Can be mentioned.

The urethane acrylate used in the present invention refers to one having a urethane bond and one or more radically curable functional groups selected from acryloyl and methacryloyl groups in its molecular chain. Although the synthesis method is not particularly limited, it can be obtained, for example, by reacting a polyhydric alcohol and 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 (e.g., succinic acid, phthalic acid, hexahydrophthalic anhydride, terephthalic acid, adipic acid, azelaic acid, tetrahydroanhydride) polyester polyols obtained by reaction with phthalic acid, etc.; polycaprolactone polyols obtained by reaction of the above polyhydric alcohol with ε-caprolactone; polycarbonate polyols (obtained by reaction of 1,6-hexanediol with diphenyl carbonate, etc.); polycarbonate diols, etc.); 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 isocyanate compounds such as isophorone diisocyanate, hexamethylene diisocyanate, tolylene diisocyanate, xylene diisocyanate, diphenylmethane-4,4'-diisocyanate, and dicyclopentanyl isocyanate, and adducts of these isocyanate compounds. Examples include isocyanate polymers.

Examples of the hydroxy(meth)acrylate compounds include pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and hydroxyethyl(meth)acrylate. ) acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, dimethylolcyclohexyl mono(meth)acrylate, hydroxycaprolactone (meth)acrylate, and the like. Among these, pentaerythritol tri(meth)acrylate and dipentaerythritol penta(meth)acrylate are preferred from the viewpoint of increasing crosslink density.

Commercially available urethane acrylates can also be used in the present invention. Examples of commercially available products include: UV1700B (10 functional), UV7620EA (9 functional), UV7610B (9 functional), UV7600B (6 functional), UV7650B (5 functional), manufactured by Nippon Kayaku Co., Ltd.: DPHA40H (10 functional), UX5003 (6 functional), manufactured by Arakawa Chemical Co., Ltd.: Beam Set 577 (6 functional), manufactured by Taisei Fine Chemical Co., Ltd.: 8UX-015A (15 functional), and manufactured by Shin Nakamura Chemical Co., Ltd.: U15HA (15 sensory), etc.

(Photoradical initiator)
When using a radical polymerization resin 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, benzoin methyl benzoate, benzoin dimethyl ketal, 2, 4-diethylthioxanthone, 1-hydroxycyclohexyl phenyl ketone, benzyl diphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, β-chloranthraquinone, (2,4,6- Examples include trimethylbenzyldiphenyl)phosphine oxide, 2-benzothiazole-N,N-diethyldithiocarbamate, and the like. 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 hardening properties, 1-Hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropane-1 -one is preferred, and 2-hydroxy-2-methyl-1-phenyl-propan-1-one and 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one are particularly preferred. 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 based on the radical curing 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. It is. By containing 85% by mass or more of the binder component, the release layer has a high crosslinking density, which increases the elastic modulus of the release layer and improves the solvent resistance of the surface of the release layer, making it possible to release ceramic green sheets. Can be peeled off with low peeling force. In the present invention, components other than the binder component and the release agent component in the release layer, such as residual solvent, acid catalyst, photocationic initiator, and photoradical initiator, are volatile or in trace amounts, and the present invention In the above, the solid content of the entire release layer is the sum of the solid content of the binder component and the release agent.

(Release agent)
The mold release agent (additive that improves the mold release properties of the mold release layer) used in the mold release layer in the present invention includes silicone-based additives and non-silicone additives such as olefin-based, long-chain alkyl-based, and fluorine-based additives. Although additives such as silicone additives can be used, it is preferable to use silicone additives from the viewpoint of releasability.

The silicone additive is a compound having a silicone skeleton in its molecule, and polyorganosiloxane and the like can be suitably used. Furthermore, acrylic resins and alkyd resins having polyorganosiloxane in their side chains can also be used. Among polyorganosiloxanes, polydimethylsiloxane (abbreviated as PDMS) can be preferably used, and polydimethylsiloxanes having a functional group in part are also preferred. Having a functional group is preferable because it facilitates the expression of intermolecular interactions such as hydrogen bonding 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 polydimethylsiloxane, amino groups, epoxy groups, hydroxy groups, mercapto groups, carboxyl groups, methacrylic groups, acrylic groups, etc. can be used. As the non-reactive functional group, polyether groups, aralkyl groups, fluoroalkyl groups, long-chain alkyl groups, ester groups, amide groups, phenyl groups, etc. can be used.

When using a melamine compound as a binder, it is preferable to use carboxyl group-modified polydimethylsiloxane which exhibits moderate interaction with the hydroxyl group of the melamine compound, although it is not particularly limited. The use of the above compound is preferable because it interacts with the binder while being appropriately segregated on the surface of the mold release layer, thereby increasing the solvent resistance of the surface of the mold release layer. Improving the solvent resistance of the surface of the release layer is preferable because the peeling force at low angles and high temperatures can be lowered.

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

When using an epoxy compound as a binder, it is preferable to use an epoxy-modified polydimethylsiloxane in consideration of the reactivity between the binder and polydimethylsiloxane. The use of the above compound is preferable because it interacts with the binder while being segregated appropriately on the surface of the mold release layer, thereby increasing the solvent resistance of the surface of the mold release layer. Improving the solvent resistance of the surface of the release layer is preferable because the peeling force at low angles and high temperatures can be lowered.

When using an acrylate compound as a binder, it is preferable to use an energy ray-curable copolymer having a (meth)acryloyl group and a polyorganosiloxane group in the molecule. By using the above compound, it is preferable because it interacts with the binder while being segregated appropriately on the surface of the mold release layer, so that the solvent resistance of the surface of the mold release layer can be increased. Improving the solvent resistance of the surface of the release layer is preferable because the peeling force at low angles and high temperatures can be lowered.

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 even more preferably 0.5% by mass or more and 5% by mass or less. If the content is 0.1% by mass or more, the mold releasability is improved and the releasability of the ceramic green sheet is improved, which is preferable. On the other hand, if it is 15% by mass or less, the elastic modulus of the entire mold release layer and the solvent resistance of the surface of the mold release layer will not decrease too much, and the mold release layer will deform when the ceramic green sheet is peeled off, resulting in a large peeling force. This is preferable because it is less likely to occur. At this time, the solid content of the entire release layer is the sum of the solid content of the binder component and the release agent.

Although the release layer in the present invention may contain particles having a particle size of 1 μm or less, it is preferable not to contain particles that form protrusions, such as particles, from the viewpoint of generating pinholes.

Additives such as adhesion improvers and antistatic agents may be added to the release layer in the present invention as long as they do not impede the effects of the present invention. Furthermore, in order to improve the adhesion to the base material, it is also preferable to subject the surface of the polyester film to pretreatment such as anchor coating, corona treatment, plasma treatment, atmospheric pressure plasma treatment, etc. before providing the release coating layer.

In the present invention, the thickness of the release layer may be set depending on the purpose of use and is not particularly limited, but it is preferably within a range where the weight of the release coating layer after curing is 0.01 to 1.5 μm. The thickness is preferably 0.05 to 1.3 μm, and even more preferably 0.1 to 1.1 μm. It is preferable that the thickness of the release layer is 0.01 μm or more because peelability can be obtained. Further, it is preferable that the thickness is 1.5 μm or less because the curing time can be shortened, the flatness of the release film can be maintained, and thickness unevenness of the ceramic green sheet can be suppressed. Further, it is preferable that the thickness of the mold release layer is thinner, since curling will be smaller when the mold release film is heated, so that poor runnability will not occur during the process of molding and drying the ceramic green sheet.

The 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 and 40 mJ/m ² or less. More preferably, it is 23 mJ/m ² or more and 35 mJ/m ² or less, and even more preferably 23 mJ/m ² or more and 30 mJ/m ² or less. If it is 18 mJ/m ² or more, it is preferable because repellency is less likely to occur when the ceramic slurry is applied and uniform application can be achieved. Moreover, if it is 40 mJ/m ² or less, there is no fear that the mold releasability of the ceramic green sheet will deteriorate, which is preferable. By setting it as the said range, there will be no repellency at the time of coating, and a release film with excellent mold releasability can be provided.

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. It is preferable that the peeling force F (T25/A90) is 0.5 mN/mm or more because the peeling force is not too light and there is no fear that the ceramic green sheet will lift up during transportation. 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. It is preferable that the peeling force is 4.5 mN/mm or less because the ceramic green sheet is less likely to be damaged during peeling.

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

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°. mm or less. It is preferable that the peel force F (T50/A90) is 7.0 mN/mm or less because the ceramic green sheet is less likely to be damaged during peeling when the peeling temperature is high.

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

In the measurement of peeling force in the present invention, a release film with a ceramic green sheet by the method described below was used as a sample for measuring peeling force, and after electricity was removed, a peeling tester (manufactured by Kyowa Kaimen Kagaku Co., Ltd., VPA-3) was used to measure the peeling force. As shown in FIG. 1, peeling was performed at a peeling angle of 90 degrees or 30 degrees, a peeling temperature of 25° C. or 50° C., and a peeling speed of 10 m/min. For the direction of peeling, stick a double-sided adhesive tape (manufactured by Nitto Denko Corporation, No. 535A) on the SUS plate attached to the peel tester, and then apply a release film on top of it by adhering the ceramic green sheet side to the double-sided tape. 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 therefore particularly suitable for producing ultra-thin ceramic green sheets.

In the present invention, in order to achieve the above peeling force, the elastic modulus of the surface of the release layer measured by a nanoindentation test is preferably 2.0 GPa or more, preferably 2.3 GPa or more. When the elastic modulus of the surface of the mold release layer is 2.0 GPa or more, the mold release layer becomes difficult to deform, so when the ceramic green sheet is peeled from the mold release layer, the mold release layer does not follow the ceramic green sheet. This 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 mold release coating layer is not particularly determined, but from the viewpoint of maintaining appropriate adhesion between the mold release coating layer and the PET base material, it is preferably 10.0 GPa or less, and 7. More preferably, it is 0 GPa or less.

In the present invention, in order to achieve the above-mentioned peeling force, it is preferable that erosion by the organic solvent is small. Erosion of the release layer can be confirmed by evaluating the difference in surface condition of the release layer before and after the release film is immersed in an organic solvent. As the organic solvent used for dipping, it is preferable to use toluene, which is commonly used in ceramic slurry, assuming a ceramic green sheet manufacturing process. An example of a method for evaluating the surface state of the mold release layer is evaluation by contact angle, and the smaller the change in the contact angle of the surface of the mold release layer before and after immersion in toluene, the better.

The type of droplet used to measure the contact angle is not particularly limited, and water, bromonaphthalene, ethylene glycol, etc. can be suitably used, but the difference in the surface state of the release layer can be seen more clearly. Most preferably, diiodomethane is used.

When diiodomethane is used as a droplet for contact angle measurement, 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 for 5 minutes at room temperature It is preferable that the smaller the absolute value of the difference (θ ₁ −θ ₂ ), the better the solvent resistance of the surface of the release layer. Specifically, the absolute value is preferably 3.0° or less, more preferably 2.0° or less, and most preferably 1.0° or less. If it is 3.0° or less, erosion of the release layer by organic solvents during ceramic green sheet processing or internal electrode printing is suppressed, and there is no risk of increasing peeling force or impairing the uniformity of peeling, which is preferable. The difference between 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 for 5 minutes at room temperature (θ ₁ - θ ₂ ) is most preferably 0°. , the absolute value may be 0.05° or more.

In the present invention, in order to achieve the above 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° or more. It is most preferable that the temperature is at least . It is preferable that the initial diiodomethane contact angle on the surface of the mold release layer is 45.0° or more, since the mold release agent that reduces the peeling force is appropriately exposed on the surface of the mold release layer, so that the peeling force can be lowered. . 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. It is preferable that the initial diiodomethane contact angle on the surface of the release layer is 100.0° or less, since wettability does not deteriorate too much when the ceramic sheet is applied, and uniform application can be achieved.

In the present invention, the method of forming the mold release layer is not particularly limited, and a coating liquid in which a mold release resin is dissolved or dispersed is spread by coating on one side of a polyester film as a base material, and a solvent etc. After removing by drying, a method of heat drying and heat curing is used.

In the present invention, when a thermosetting resin such as melamine is used as a binder in the release layer, the drying temperature during solvent drying and thermosetting is preferably 100°C or higher and 180°C or lower, 110°C or higher, The temperature 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. A temperature of 180° C. or lower is preferable because the flatness of the film is maintained and there is little risk of uneven thickness of the ceramic green sheet. It is particularly preferable that the temperature is 140° C. or lower, since the film can be processed without impairing its flatness, and the possibility of causing thickness unevenness of the ceramic green sheet is further reduced. It is preferable that the temperature is 100° C. or higher because the curing reaction of the thermosetting resin sufficiently proceeds and the elastic modulus of the release layer increases.

When an active energy ray-curable resin such as epoxy or acrylate is used as a binder in the release layer of the present invention, the drying temperature for solvent drying is preferably 50°C or higher and 110°C or lower, and preferably 60°C or higher and 100°C or higher. It is more preferable that the temperature is below ℃. The drying time is preferably 30 seconds or less, more preferably 20 seconds or less. Furthermore, after drying the solvent, active energy rays are irradiated to advance the curing reaction. As active energy rays used at this time, ultraviolet rays, electron beams, X-rays, etc. can be used, but ultraviolet rays are preferred 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 . By setting it to 30 mJ/cm2 or ^more , the curing of the resin will proceed sufficiently, and by setting it to 300 mJ/ ^cm2 or less, the speed during processing can be improved, so that a release film can be created economically, which is preferable. .

In the present invention, the surface tension of the coating liquid when applying the release layer is not particularly limited, but is preferably 30 mN/m or less. By controlling the surface tension as described above, it is possible to improve the applicability after coating and reduce the unevenness of the coating film surface after drying.

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 with 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 added is preferably about 10 to 80% by mass based on the entire coating liquid.

Any known coating method can be applied to apply the above coating liquid, such as roll coating methods such as gravure coating method and reverse coating method, bar coating method such as wire bar coating method, die coating method, spray coating method, and air knife coating method. Conventionally known methods such as a coating method can be used.

The surface of the release layer of the release film of the present invention is desirably flat in order to prevent defects from occurring in the ceramic green sheet coated and molded thereon, and the surface average roughness (Sa) of the area is preferably 7 nm or less. It is preferable that there be. Further, it is more preferable that the above-mentioned Sa is satisfied and that the maximum protrusion height (P) on the surface of the release layer is 100 nm or less. It is particularly preferable that the area surface average roughness (Sa) is 5 nm or less and the maximum protrusion height is 80 nm or less. If the area surface roughness is 7 nm or less and the maximum protrusion height is 100 nm or less, defects such as pinholes will not occur during the formation of the ceramic green sheet, and the yield will be good, which is preferable. Although it can be said that the smaller the area 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 roughness 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. In addition, "containing substantially no inorganic particles" as used in the present invention means that both the base film and the release coating layer contain 50 ppm or less when the elements derived from the particles are quantitatively analyzed by X-ray fluorescence analysis. It is preferably 10 ppm or less, most preferably below the detection limit. This is because even if particles are not actively added to the base film, contaminants derived from foreign substances and dirt attached to the raw resin or the line or equipment in the film manufacturing process are peeled off and mixed into the film. This is because there are cases where

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

The release film for producing ceramic green sheets of the present invention is used to produce such laminated ceramic capacitors. For example, it is manufactured as follows. First, using the release film of the present invention as a carrier film, a ceramic slurry for forming a ceramic body is applied and dried. 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 printed with a conductive layer for forming the first internal electrode, and a ceramic green sheet printed with a conductive layer for forming the second internal electrode are laminated as appropriate and pressed. By this, a mother laminate is obtained. The mother laminate is divided into multiple parts to produce raw ceramic bodies. A ceramic body is obtained by firing a raw ceramic body. Thereafter, the multilayer ceramic capacitor can be completed by forming the first and second external electrodes.

The present invention will be explained in more detail below using Examples, but the present invention is not limited to these Examples in any way. The characteristic values used in the present invention were evaluated using the following method.

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

(Method for producing release film with ceramic green sheet)
A composition consisting of the following materials was stirred and mixed and dispersed for 60 minutes using a bead mill using zirconia beads with 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 Co., Ltd.) 10.86 parts by mass Polyvinyl butyral (S-LEC BM-S manufactured by Sekisui Chemical Co., Ltd.) 1.09 parts by mass DOP (phthalic acid Dioctyl) 0.55 parts by mass Next, the dried slurry was applied to the release surface of the obtained release film sample using an applicator to a thickness of 1.0 μm, and dried at 90°C for 2 minutes to form a ceramic green sheet. was molded onto a release film.

(Evaluation of ceramic green sheet removability)
The ceramic green sheet-attached release film produced in the above method was cut into pieces of 30 mm width and 80 mm length, and used as samples for peel force measurement. After removing the static electricity using a static eliminator (manufactured by Keyence Corporation, SJ-F020), using a peel tester (manufactured by Kyowa Kaimen Kagaku Co., Ltd., VPA-3), the peeling angle was 90 degrees or 30 degrees, and the peeling temperature was 25 degrees Celsius or 50 degrees Celsius. The film was peeled off at a temperature of 10 m/min at a peeling speed of 10 m/min. For the direction of peeling, stick a double-sided adhesive tape (manufactured by Nitto Denko Corporation, No. 535A) on the SUS plate attached to the peel tester, and then apply a release film on top of it by adhering the ceramic green sheet side to the double-sided tape. was fixed and peeled off by pulling the release film side. Among the measured values obtained, the peeling force was averaged over a peeling distance of 20 mm to 70 mm, and this value was taken as the peeling force. The measurement was carried out five times in total, and the average value of the peeling force was used for evaluation. Judgment was made based on the obtained peel force values based on the following criteria.
○: 45.0 mN/mm or less △: Greater than 45.0 mN/mm and 60.0 mN/mm or less ×: Greater than 60.0 mN/mm Note that the peel angle in this evaluation method refers to the Refers to the angle in the direction in which the release film is pulled with respect to the axis of the evaluation sample. The peeling temperature is the temperature when the fixed release film is heated using a heater stage system attached to the apparatus. After confirming that the measured sample has reached the appropriate temperature using a handy thermometer (manufactured by Anritsu Keiki Co., Ltd., HD-1400E), peeling is performed.

(contact angle)
Diiodomethane (droplet amount A droplet of 0.9 μL was prepared and its contact angle was measured. For the contact angle, the contact angle 30 seconds after dropping onto the release film was used, and the average value of the values measured five times was used.

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

The initial diiodomethane contact angle on the surface of the release layer before immersion in toluene measured by the above method is θ ₁ , and the contact angle of diiodomethane on the surface of the release _layer after immersion in toluene is _{θ 2} . The absolute value was taken as the value of the contact angle change before and after immersion in toluene. Initial contact angle and contact angle change were evaluated based on the following criteria.
(Evaluation of initial contact angle)
○:45.0°≦ _θ1
×: θ ₁ < 45.0°
(Evaluation of contact angle change)
◎:｜θ ₁ - θ ₂ ｜ < 1.0°
○: 1.0°≦ | θ ₁ - θ ₂ | < 2.0°
△: 2.0°≦ | θ ₁ - θ ₂ | ≦ 3.0°
×: |θ ₁ −θ ₂ | > 3.0°

(Release layer elastic modulus evaluation)
The release films obtained in Examples and Comparative Examples were cut into a size of 10 mm x 10 mm, and then the back side of the base material of the cut release films was bonded with two-component epoxy onto a glass plate adhered to an aluminum pedestal. Fixed with agent. Then, using a microhardness evaluation device (manufactured by Elionix Co., Ltd., ENT-3100), a nanoindentation test was performed in an atmosphere at 23°C with a maximum indentation depth of 50 nm, and the release layer of the release film was The elastic modulus of the sample was measured. The results are shown in Table 2.

(Preparation of polyethylene terephthalate pellets (PET(I)))
As the esterification reactor, a continuous esterification reactor consisting of a three-stage complete mixing tank having a stirrer, a partial condenser, a raw material inlet, and a product outlet was used. TPA (terephthalic acid) is set at 2 tons/hour, EG (ethylene glycol) is set at 2 moles per 1 mole of TPA, antimony trioxide is set at an amount such that Sb atoms are 160 ppm relative to the produced PET, and these slurries are converted into esters. The mixture was continuously supplied to the first esterification reactor of the esterification reactor, and reacted at 255°C for an average residence time of 4 hours at normal pressure. Next, the reaction product in the first esterification reactor is continuously taken out of the system and supplied to the second esterification reactor, and the reaction product is distilled from the first esterification reactor into the second esterification reactor. In addition, an EG solution containing magnesium acetate tetrahydrate in an amount such that Mg atoms are 65 ppm relative to the produced PET, and 40 ppm P atoms relative to the produced PET is supplied. An EG solution containing an amount of TMPA (trimethyl phosphate) was added, and the mixture was reacted at 260°C for an average residence time of 1 hour at normal pressure. Next, the reaction product of the second esterification reactor was continuously taken out of the system and supplied to the third esterification reactor, and was heated to 39 MPa (400 kg/cm ² ) using a high-pressure disperser (manufactured by Nippon Seiki Co., Ltd.). Average particles made of 0.2% by mass of porous colloidal silica with an average particle diameter of 0.9 μm that has been subjected to dispersion treatment at a pressure of 5 times on average and 1% by mass of ammonium salt of polyacrylic acid per calcium carbonate. While adding 0.4% by mass of synthetic calcium carbonate having a diameter of 0.6 μm as a 10% EG slurry, the mixture was reacted at 260° C. for an average residence time of 0.5 hours at normal pressure. The esterification reaction product produced in the third esterification reactor was continuously fed to a three-stage continuous polycondensation reactor to perform polycondensation, and stainless steel fibers with a 95% cut diameter of 20 μm were sintered. After filtration with a filter, ultrafiltration was performed and extruded into water, and after cooling, it was 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 above PET (I) chip, a PET chip with an intrinsic viscosity of 0.62 dl/g containing no particles of calcium carbonate, silica, etc. was obtained (hereinafter abbreviated as PET (II)).

(Manufacture of laminated film X1)
After drying, these PET chips were melted at 285°C, melted at 290°C by a separate melt extruder extruder, and filtered with sintered stainless steel fibers with a 95% cut diameter of 15 μm and a filter with a 95% cut diameter of 15 μm. Two stages of filtration are performed using a filter made of sintered stainless steel particles of 15 μm, which are combined in the feed block to form PET (I) on the surface layer B (anti-release side layer) and PET (II) on the surface layer. Laminated to form layer A (release side layer), extruded (casting) into a sheet at a speed of 45 m/min, electrostatically adhered and cooled on a casting drum at 30°C using 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 by calculating the discharge amount of each extruder so that PET (I)/(II) = 60% by mass/40% by mass. Next, this unstretched sheet was heated with an infrared heater, and then stretched 3.5 times in the machine direction at a roll temperature of 80° C. using a speed difference between the rolls. Thereafter, it was introduced into a tenter and stretched 4.2 times in the transverse direction at 140°C. Then, heat treatment was performed at 210° C. in a heat fixing zone. Thereafter, a 2.3% relaxation treatment was performed at 170° C. in the transverse direction 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 acid tetra(3,4-epoxycyclohexylmethyl modified ε-caprolactone (Product name: Epolead (registered trademark) GT401, manufactured by Daicel, solid content 100% by mass)
(A-3) Epoxy compound (alicyclic epoxy compound)
Polyfunctional alicyclic epoxy group-containing polymer (product name: EHPE (registered trademark) 3150, manufactured by Daicel, solid content 100% by mass)
(B-1) Acrylate compound (6 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: Shiko (registered trademark) UV1700B, manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd., solid content 100% by mass)
(C-1) Melamine compound hexamethoxymethyl melamine, solid content 100%, manufactured by Tokyo Kasei Kogyo Co., Ltd. (Product name: N,N,N',N',N'',N''-hexakis(methoxymethyl)) Melamine, molecular weight 390)
(C-2) Melamine compound hexamethoxymethylmelamine, solid content 100%, manufactured by MT Aquapolymer Co., Ltd. (product name Cymel 303)

(Example 1)
On the surface layer A of the laminated film A release film for producing a ceramic green sheet was obtained by irradiating the film with ultraviolet light of /cm ² using an ultraviolet irradiator (LC6B, H bulb, manufactured by Heraeus). When a ceramic slurry was applied to the obtained release film using 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, solid content 100% by mass))
Mold release agent 1.00 parts by mass (alicyclic epoxy group-containing silicone resin, UV POLY215, solid content 100%, manufactured by Arakawa Chemical Industry Co., 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 ceramic green sheets was obtained in the same manner as in Example 1, except that coating liquid 2 having the composition shown below was used.
(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: Epolead (registered trademark) GT401, manufactured by Daicel Corporation, solid content 100%)
Mold release agent 1.00 parts by mass (alicyclic epoxy group-containing silicone resin, UV POLY215, solid content 100%, manufactured by Arakawa Chemical Industry Co., 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 ceramic green sheets was obtained in the same manner as in Example 1, except that coating liquid 3 having the composition shown below was used.
(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 Corporation, solid content 100% by mass)
Mold release agent 1.00 parts by mass (alicyclic epoxy group-containing silicone resin, UV POLY215, solid content 100%, manufactured by Arakawa Chemical Industry Co., Ltd.)
Photocation initiator 1.00% parts by mass (hexafluoroantimonate triarylsulfonium salt)
(Product name: CPI (registered trademark) 101A, active ingredient 50% by mass, manufactured by Sun-Apro)

(Example 4)
A release film for producing ceramic green sheets was obtained in the same manner as in Example 1 except that Coating Liquid 1 was changed to 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 Co., Ltd., solid content 100% by mass )
(Meth)acryloyl group-containing copolymerized silicone acrylic polymer 1.00 parts by mass (product name: GL-04R, manufactured by Kyoeisha Chemical Co., Ltd., solid content 20%)
α-Hydroxyalkylphenone 0.80 parts by mass (Product name: IRGACURE127, manufactured by BASF, 100% active ingredient)

(Example 5)
A release film for producing ceramic green sheets was obtained in the same manner as in Example 1, except that Coating Liquid 1 was changed to 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: Shiko (registered trademark) UV1700B, manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd., solid content 100% by mass)
(Meth)acryloyl group-containing copolymerized silicone acrylic polymer 1.00 parts by mass (product name: GL-04R, manufactured by Kyoeisha Chemical Co., Ltd., solid content 20%)
α-Hydroxyalkylphenone 0.80 parts by mass (Product name: IRGACURE127, manufactured by BASF, 100% active ingredient)

(Example 6)
Coating liquid 6 having the following composition was applied on the surface layer A of the laminated film A release film for producing ceramic green sheets 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 Kasei Kogyo Co., Ltd., product name N,N,N',N ',N'',N''-hexakis(methoxymethyl)melamine, molecular weight 390))
Mold release agent 0.50 parts by mass (one-end carboxyl-modified polydimethylsiloxane, X22-3710, solid content 100%, manufactured by Shin-Etsu Chemical Co., Ltd., an alkyl group is interposed between the dimethylsiloxane and the 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 release agent (X22-3710) added to coating liquid 6 in Example 6 was changed to 0.20 parts by mass.

(Example 8)
The procedure was the same as in Example 6, except that the amount of hexamethoxymethylmelamine added in Coating Solution 6 of Example 6 was changed to 9.0 parts by mass, and the amount of mold release agent (X22-3710) added was changed to 1.0 parts by mass. A release film for ceramic green sheet production was obtained.

(Example 9)
The procedure was the same as in Example 6, except that the amount of hexamethoxymethylmelamine added in Coating Solution 6 of Example 6 was changed to 8.0 parts by mass, and the amount of mold release agent (X22-3710) added was changed to 2.0 parts by mass. A release film for ceramic green sheet production was obtained.

(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 thickness of the release layer in Example 6 was changed to the thickness shown in Table 2.

(Comparative example 1)
A release film for producing ceramic green sheets was obtained in the same manner as in Example 1, except that Coating Liquid 1 was changed to Coating Liquid 7. In Comparative Example 1, polyether-modified silicone that does not interact with the epoxy binder component was used, so the solvent resistance of the surface of the release layer was poor, and the peeling force at low angles and high temperatures was significantly 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, solid content 100% by mass))
Mold release agent 1.00 parts by mass (polyether modified silicone resin, BYK-302, solid content 100%, manufactured by Arakawa Chemical Industry Co., 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 ceramic green sheets was obtained in the same manner as in Example 1, except that Coating Liquid 1 was changed to Coating Liquid 8. In Comparative Example 2, the solvent resistance near the surface of the mold release layer deteriorated because a mold release agent whose main chain was polydimethylsiloxane was used and surface hardening was inhibited by oxygen, which is characteristic of radical polymerization. . As a result, although the modulus of elasticity of the release layer was high, the release force at low angles and high temperatures became significantly high because the solvent resistance of the surface of the release layer was poor.
(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 Co., Ltd., solid content 100% by mass )
Acryloyl group-containing polyether-modified polydimethylsiloxane 0.20 parts by mass (product name: BYK-UV3500, manufactured by Big Chemie Japan, solid content 100%)
α-Hydroxyalkylphenone 0.80 parts by mass (Product name: IRGACURE127, manufactured by BASF, 100% active ingredient)

(Comparative example 3)
A release film for ceramic sheet production was obtained in the same manner as in Example 6, except that Coating Liquid 6 was changed to Coating Liquid 9. In Comparative Example 3, in which a large amount of mold release agent was added and the melamine resin was only 70% by mass of the mold release layer, the elastic modulus of the mold release layer was low and the solvent resistance of the surface of the mold release layer was also poor, so the peel strength of the ceramic green sheet decreased. has grown larger. 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 Kasei Kogyo Co., Ltd.)
Mold release agent 3.00 parts by mass (one-end 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 producing a ceramic sheet was obtained in the same manner as in Example 1 except that Coating Liquid 1 was changed to Coating Liquid 10 below. The interaction between the hydroxyl group of the mold release agent and the melamine resin is strong, and the mold release agent does not appear on the surface. Although the elastic modulus of the mold release layer is high and the solvent resistance of the surface of the mold release layer is high, the peeling force is low. 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 Aqua Polymer Co., Ltd., trade name Cymel 303)
Mold release agent 1.00 parts by mass (polyester modified OH group-containing polydimethylsiloxane, BYK-370, solid content 25%, manufactured by BYK Chemie Japan)
Acid catalyst (para-toluenesulfonic acid) 0.50 parts by mass

The evaluation results for each example and comparative example are shown in Tables 1 and 2.

In Examples 1 to 12, since the peeling force was low at a peeling angle of 30° and a peeling temperature of 50°C, it was possible to peel off the ceramic sheet without damaging it and obtain a high-quality ceramic capacitor. In Comparative Examples 1 to 4, the peeling force at a peeling angle of 30° and a peeling temperature of 50° C. was high, which caused damage to the ceramic sheet, resulting in poor yield of ceramic capacitors.

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 the ultra-thin layer of ceramic green can suppress damage to the ceramic green sheet. 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: Tensile direction 7: Peeling angle 8: Release film 9: Release film with ceramic green sheet

Claims (9)

A polyester film is used as a base material, and the base material has a surface layer A that does not substantially contain inorganic particles on at least one side,
A release film in which a release layer is laminated directly or via another layer on the surface of the surface layer A on at least one side,
The diiodomethane contact angle θ1 on the surface of the release layer is 45.0° or more,
The absolute value of 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 on the surface of the release layer after immersing the release film in toluene for 5 minutes at room temperature is: 3.0° or less,
The binder component in the release layer is a melamine compound, an epoxy compound,
Containing at least one crosslinked acrylate compound,
When the binder component contains an epoxy compound, the binder component further contains a photocationic polymerization initiator.
Release film. The ceramic green sheet production according to claim 1, wherein the coating elastic modulus measured from the surface of the release layer opposite to the base material by a nanoindentation test on the release layer is 2.0 GPa or more. Release film for use. 2. The ceramic green sheet manufacturing method according to claim 1, wherein the release layer is formed by hardening a coating film containing at least a release agent and a binder component, and the binder component accounts for 85% by mass or more of the solid content of the release layer. Release film. The mold release agent contains a silicone skeleton,
Furthermore, it has at least one functional group selected from the group consisting of an epoxy group, an acryloyl group, and a carboxyl group,
The content of the mold release agent is 0.1% by mass or more and 15% by mass or less based on the solid content of the mold release layer.
The release film for producing ceramic green sheets according to claim 3 . The release film for producing ceramic green sheets according to claim 1, wherein the release layer has a thickness of 0.01 μm to 1.5 μm. The surface layer B forming the surface layer on the opposite side 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 number of particles is the surface layer B. The release film for producing ceramic green sheets according to claim 1, wherein the release film contains 5,000 to 15,000 ppm. The film according to claim 1, wherein the surface layer A has a surface average roughness (Sa) of 0.1 nm or more and 7 nm or less, and the surface layer B has a surface average roughness (Sa) of 1 to 40 nm. Release film for ceramic green sheet production. A method for manufacturing a ceramic green sheet, comprising molding a ceramic green sheet using the release film for manufacturing a ceramic green sheet according to any one of claims 1 to 7, wherein the molded ceramic green sheet has a diameter of 0.2 μm to 1 μm. A method for manufacturing a ceramic green sheet having a thickness of .0 μm. A method for manufacturing a ceramic capacitor, which employs the method for manufacturing a ceramic green sheet according to claim 8.