JP7306514B2 - Release film for manufacturing ceramic green sheets - Google Patents

Description

The present invention relates to a release film for manufacturing ceramic green sheets, and more specifically, suppresses the occurrence of green sheet defects such as pinholes and unevenness in thickness, and process defects such as poor peeling when manufacturing ultra-thin ceramic green sheets. The present invention relates to a release film for producing a ceramic green sheet that can be used.

Conventionally, a release film obtained by laminating a release layer on a polyester film as a base material has been used for molding ceramic green sheets such as laminated ceramic capacitors and ceramic substrates. In recent years, along with miniaturization and increase in capacity of laminated ceramic capacitors, the thickness of ceramic green sheets tends to be reduced. A ceramic green sheet is formed by coating a release film with a slurry containing a ceramic component such as barium titanate and a binder resin such as polyvinyl acetal resin and drying the slurry. After electrodes are printed on the molded ceramic green sheets and separated from the release film, the ceramic green sheets are laminated, pressed, fired, and external electrodes are applied to manufacture the laminated ceramic capacitor. Until now, when molding a ceramic green sheet on the release layer surface of a polyester film, minute protrusions on the surface of the release layer affect the molded ceramic green sheet, and defects such as cissing and pinholes are likely to occur. There was a problem. Therefore, techniques have been developed for realizing a release layer surface with excellent flatness (see, for example, Patent Document 1).

However, in recent years, the thickness of ceramic green sheets has been further reduced, and ceramic green sheets having a thickness of 1.0 μm or less, more specifically, a thickness of 0.2 μm to 1.0 μm have been required. Therefore, a release film having a smoother release layer surface is desired. In addition, as the thickness of the ceramic green sheet decreases, the strength of the ceramic green sheet decreases. Therefore, it is desired that the peel force when peeling the ceramic green sheet from the release film be low and uniform. That is, it is becoming more important to minimize the force applied to the ceramic green sheets when peeling the ceramic green sheets from the release film so as not to damage the ceramic green sheets.

In recent years, it has been reported that the release layer surface is excellent in smoothness and releasability by UV-curing a release layer composed mainly of a radical-curable substance that reacts under irradiation with active energy rays. was found (see, for example, Patent Documents 2 and 3). More specifically, curing the radical-curable substance with ultraviolet rays increases the elastic modulus of the release layer, making it difficult for the release layer to deform when peeled off (the release layer is less likely to follow the ceramic green sheet). A release layer having excellent releasability can be obtained. At the same time, the release agent contained in the composition (additive added to impart releasability) segregates on the surface of the release layer during drying, resulting in excellent smoothness and improved releasability. An excellent release layer can be obtained.

However, according to Patent Documents 2 and 3, a silicone component represented by polydimethylsiloxane is used as a release agent. Therefore, the release layer surface, where the silicone component is thought to be segregated, has a lower elastic modulus due to the flexibility derived from the silicone skeleton. was there. Moreover, the solvent resistance of the silicone component has also been a problem. More specifically, the surface of the release layer is corroded by the organic solvent used in molding the ceramic green sheets and printing the internal electrodes, which may cause problems in the smoothness and peelability of the ceramic green sheets. In addition, the silicone component may transfer to the ceramic green sheets, resulting in process failures such as poor adhesion, or contamination of products, resulting in reduced reliability.

JP-A-2000-117899 WO2013/145864 WO2013/145865

The present invention has been made against the background of such problems of the prior art. That is, the object of the present invention is to provide a release layer having a low and uniform release force and excellent solvent resistance while maintaining high smoothness on the surface of the release layer of the release film. To provide a release film for producing a ceramic green sheet, which can form a ceramic green sheet having few defects even in an ultra-thin layer of 1 μm or less.

That is, the present invention consists of the following configurations.
1. A release film comprising a release layer provided on at least one side of a polyester film directly or via another layer, wherein the release layer contains a binder component (a) and a silsesquioxane component (b) Release film for manufacturing ceramic green sheets, which is obtained by curing a material.
2. 1. The release film for producing a ceramic green sheet according to 1 above, wherein the content of the silsesquioxane component (b) relative to the total solid content of the composition is 0.01% by mass to 60% by mass.
3. 2. The release film for producing a ceramic green sheet according to 1 or 2 above, wherein the silsesquioxane component (b) has a polyorganosiloxane group in the molecule.
4. 3. The release film for producing a ceramic green sheet according to any one of the above 1 to 3, wherein the release layer surface has an area surface average roughness (Sa) of 7 nm or less.
5. The binder component (a) is a radically curable substance, and the silsesquioxane component (b) has at least one reactive functional group selected from an acryloyl group, a methacryloyl group, an alkenyl group and a thiol group in the molecule. 4. The release film for producing a ceramic green sheet according to any one of 1st to 4th above.
6. The binder component (a) is a cationic curable substance, and the silsesquioxane component (b) has at least one reactive functional group selected from an epoxy group, an alicyclic epoxy group and an oxetanyl group in the molecule. 4. The release film for producing a ceramic green sheet according to any one of 1st to 4th above.
7. The binder component (a) is a melamine-based substance, and the silsesquioxane component (b) has in its molecule at least one reactive functional group selected from hydroxyl, carboxyl, amino and hydrosilyl groups. The release film for manufacturing a ceramic green sheet according to any one of 1st to 4th.
8. The polyester film has a surface layer A that does not substantially contain inorganic particles and an opposite surface layer B that contains inorganic particles, a release layer is provided on the surface layer A, and the surface layer The ceramic green sheet according to any one of the above 1st to 7th, wherein the inorganic particles contained in B are silica particles and/or calcium carbonate particles, and the total amount of the inorganic particles is contained in the surface layer B at 5000 to 15000 ppm. Release film for manufacturing.
9. 10. A method for producing a ceramic green sheet having a thickness of 0.2 μm to 1.0 μm, wherein the release film for producing a ceramic green sheet according to any one of the first to eighth is used. . A method for manufacturing a ceramic capacitor employing the method for manufacturing a ceramic green sheet according to the ninth aspect.

The release film for producing a ceramic green sheet of the present invention has higher hardness and solvent resistance on the surface of the release layer than the release layer of a conventional release film, so it is excellent in releasability and prevents migration of Si-containing components. can be suppressed. Therefore, it is possible to provide a release film for manufacturing a ceramic green sheet that does not cause defects in the ceramic green sheet and process defects such as poor peeling and poor adhesion even when manufacturing an ultra-thin ceramic green sheet.

In the present invention, a release layer is provided on at least one side of a polyester film directly or via another layer, and the release layer contains a binder component (a) and a silsesquioxane component (b). It is preferable that the The present invention will be described in detail below.

(polyester film)
The polyester constituting the polyester film used as the base material of the present invention is not particularly limited, and it is possible to use a film-molded polyester that is commonly used as a base material for a release film, but preferably, It is preferably a crystalline linear saturated polyester comprising an aromatic dibasic acid component and a diol component, such as polyethylene terephthalate, polyethylene-2,6-naphthalate, polybutylene terephthalate, polytrimethylene terephthalate, or resins thereof. Component-based copolymers are more preferred, and polyester films formed from polyethylene terephthalate are particularly preferred. In polyethylene terephthalate, the repeating unit of ethylene terephthalate is preferably 90 mol % or more, more preferably 95 mol % or more, and may be copolymerized with a small amount of other dicarboxylic acid component or diol component, but from the viewpoint of cost. , preferably made only from terephthalic acid and ethylene glycol. In addition, known additives such as antioxidants, light stabilizers, ultraviolet absorbers, crystallization agents, etc. may be added within limits that do not impair the effects of the film of the present invention. The polyester film is preferably a biaxially oriented polyester film because of its high bidirectional elastic modulus.

The intrinsic viscosity of the polyethylene terephthalate film is preferably 0.50 to 0.70 dl/g, more preferably 0.52 to 0.62 dl/g. When the intrinsic viscosity is 0.50 dl/g or more, it is preferable because many breakages do not occur in the stretching process. Conversely, when it is 0.70 dl/g or less, the cutting performance is good when cutting into a predetermined product width, and dimensional defects do not occur, which is preferable. Moreover, it is preferable to sufficiently vacuum-dry the raw material.

The method for producing the polyester film in the present invention is not particularly limited, and conventionally generally used methods can be used. For example, the polyester can be melted by an extruder, extruded into a film, cooled by a rotating cooling drum to obtain an unstretched film, and biaxially stretched to obtain 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 direction or longitudinal direction, or by a method of simultaneously biaxially stretching an unstretched film in the longitudinal direction and the lateral direction. I can.

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 that the film is stretched 1 to 8 times, particularly 2 to 6 times, in each of the longitudinal and transverse directions.

The polyester film preferably has a thickness of 12 to 50 μm, more preferably 15 to 38 μm, and still more preferably 19 to 33 μm. 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, and molding. On the other hand, if the thickness of the film is 50 μm or less, the amount of the film to be discarded after use is not excessively increased, which is preferable for reducing the environmental load.

The polyester film substrate may be a single layer or a multilayer of two or more layers, but is preferably a laminated film having 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 capable of containing inorganic particles and the like on the opposite side of the surface layer A which does not substantially contain inorganic particles. As a laminated structure, the layer on the side where the release layer is applied is layer A, the layer on the opposite side is layer B, and the core layer other than these is layer C. The layer configuration in the thickness direction is release layer / A / B, or a laminated structure such as release layer/A/C/B. Of course, the C layer may have a multi-layer structure. In addition, the surface layer B may not contain inorganic particles. In that case, it is preferable to provide a coating layer containing at least inorganic particles and a binder on the surface layer B in order to impart lubricity for winding the film into a roll.

In the polyester film substrate of the present invention, the surface layer A forming the surface to be coated with the release layer preferably 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 and the like are less likely to occur during molding of laminated ultra-thin ceramic green sheets, 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 the below-described anchor coat layer or the like 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 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 that the inorganic particles are 50 ppm or less, preferably 10 ppm or less, most preferably less than the detection limit when the inorganic elements are quantified by fluorescence X-ray analysis. means content. This is because even if inorganic particles are not positively added to the film, contaminants derived from foreign substances and dirt adhering to the lines and equipment in the raw material resin or film manufacturing process peel off and mix into the film. This is because there are cases.

In the polyester film substrate of the present invention, the surface layer B, which forms the surface opposite to the surface to which the release layer is applied, preferably contains inorganic particles from the viewpoint of film slipperiness and ease of air release. In particular, silica particles and/or calcium carbonate particles are preferably used. The content of the inorganic particles contained in the surface layer B is preferably 5000 to 15000 ppm in total of the inorganic particles. At this time, the area average surface 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, when the film is wound into a roll, air can escape uniformly, resulting in a good roll shape and good flatness. , suitable for the production of ultra-thin ceramic green sheets. In addition, when the total amount of silica particles and/or calcium carbonate particles is 15000 ppm or less and Sa is 40 nm or less, aggregation of the lubricant is difficult to occur and coarse protrusions cannot be formed, so that the quality is stable when manufacturing an ultra-thin ceramic green sheet. and preferred.

As the particles contained in the B layer, inactive inorganic particles and/or heat-resistant organic particles can be used in addition to silica and/or calcium carbonate. More preferably, calcium carbonate particles are used. Inorganic particles that can also be used include alumina-silica composite oxide particles, hydroxyapatite particles, and the like. Examples of 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 inorganic 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. If the average particle size of the inorganic particles is 0.1 μm or more, the slipperiness of the release film is good, which is preferable. In addition, if the average particle size is 2.0 μm or less, it is preferable because there is no fear of generating pinholes 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 kinds of particles made of different materials. Further, particles of the same type but different in average particle diameter may be contained.

When the surface layer B does not contain particles, it is preferable that a coating layer containing particles on the surface layer B provides lubricity. Although the present coat layer is not particularly limited, it is preferably provided as an in-line coat that is applied during film formation of the polyester film. When the surface layer B does not contain particles and the surface layer B has a coat layer containing particles, the surface of the coat layer has a region surface roughness (Sa) for the same reason as the region surface roughness (Sa) of the surface layer B The average surface roughness (Sa) is preferably in the range of 1-40 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 recycled raw materials in the surface layer A, which is the layer on which the release layer is provided, in order to prevent inorganic particles such as lubricants 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 layer thickness of the base film. If it is 20% or more, the inside of the film is less likely to be affected by the particles contained in the surface layer B, etc., and it is easy for the region surface average roughness Sa to satisfy the above range, which is preferable. When the total thickness of the base film is 50% or less of the total thickness 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 small, which is preferable.

From the viewpoint of economy, the layers other than the surface layer A (the surface layer B or the intermediate layer C described above) may contain 50 to 90% by mass of recycled film scraps and PET bottle raw materials. Even in this case, the type and amount of the lubricant contained in the B layer, the particle size, and the area surface average roughness (Sa) preferably satisfy the above ranges.

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

(release layer)
The release layer in the present invention is preferably formed by curing a composition containing a binder component (a) and a silsesquioxane component (b). Here, in the present invention, the binder component (a) and the silsesquioxane component (b) are considered to have a changed structure after being cured in the coating layer. Since it is extremely difficult to accurately express and describe it, as described above, "the release layer is formed by curing a composition containing a binder component (a) and a silsesquioxane component (b). ” is expressed.

(Binder component (a))
The binder component (a) is preferably a component that can be cured under heat or active energy ray irradiation to form a coating film with a high elastic modulus. Examples of the thermosetting binder component include epoxy-based substances and melamine-based substances. From the viewpoint of reactivity, it is preferable to use melamine-based substances. As the active energy ray-curable binder component, a radical-curable substance and a cationic-curable substance are preferable, and each of them can be suitably used.

The radical-curable substance in the present invention preferably has at least one reactive functional group selected from an acryloyl group, a methacryloyl group, an alkenyl group and a thiol group and is cured under ultraviolet irradiation. The cationic curable substance preferably has at least one reactive functional group selected from an epoxy group, a vinyl ether group, an alicyclic epoxy group, and an oxetanyl group and is cured under ultraviolet irradiation. The alkenyl group in the present invention refers to those having 2 to 10 carbon atoms such as vinyl group, allyl group, propenyl group and hexenyl group.

The melamine-based substance used as the binder component (a) is not particularly limited and can be a general one. preferably have one or more of each. Specifically, a methylolmelamine derivative obtained by condensing melamine and formaldehyde is preferably etherified by dehydration condensation reaction with a lower alcohol such as methyl alcohol, ethyl alcohol, isopropyl alcohol, or butyl alcohol. Examples of methylolated melamine derivatives include monomethylolmelamine, dimethylolmelamine, trimethylolmelamine, tetramethylolmelamine, pentamethylolmelamine, and hexamethylolmelamine. 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 suppress deformation of the release layer. Therefore, it is preferable to use hexamethylolmelamine, which has many cross-linking points in one molecule, as the melamine-based substance used for the release layer, which can increase the cross-linking density of the release layer.

As the melamine-based material used in the release layer of the present invention, when using an ether compound obtained by dehydration condensation reaction of a methylolmelamine derivative with alcohol, from the viewpoint of reactivity, hexamethoxy obtained by dehydration condensation with methyl alcohol Methylmelamine is particularly preferred.

When using a melamine-based material in the release layer of the present invention, it is preferable to add a catalyst to promote the cross-linking reaction of the melamine-based material. The catalyst to be used is not particularly limited, but an existing acid catalyst can be used, and a carboxylic acid catalyst is preferably used. Metal salt type, phosphate ester type, and sulfonic acid type can be preferably used. Block-type catalysts in which acid sites are blocked can also be used.

Examples of carboxylic acid-based catalysts that can be used include benzoic acid, acetic acid, formic acid, oxalic acid, propionic acid, and derivatives thereof. The use of a carboxylic acid-based catalyst is preferable because it can suppress curling of the release film due to an excessive increase in crosslink density due to appropriate reactivity. In particular, 4-methylbenzoic acid is inexpensive, readily available and easy to use.

The radical-curable substance used as the binder component (a) may be a monomer, an oligomer, or a polymer. Acrylates, methacrylates, urethane acrylates, allyl compounds and methallyl compounds are preferred, and acrylates, methacrylates and urethane acrylates are particularly preferred.

The radical-curable substance used as the binder component (a) may be a monomer, an oligomer, or a polymer, but from the viewpoints of solubility in organic solvents and handling properties, it is preferable to use a monomer or an oligomer. These may be used alone or in combination of two or more.

When using a monomer as a (meth)acrylate, for example, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol Tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethoxylated isocyanurate tri(meth)acrylate, caprolactone-modified dipentaerythritol hexa(meth)acrylate and the like.

When oligomers are used as (meth)acrylates, examples include polyfunctional (meth)acrylate oligomers, polyester acrylate oligomers, epoxy acrylate oligomers, polyether acrylate oligomers, polybutadiene acrylate oligomers, and silicone acrylate oligomers. .

The urethane acrylate used in the present invention means one having a urethane bond and one or more radical-curing functional groups selected from acryloyl groups and methacryloyl groups in the 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 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 polyol obtained by reaction with phthalic acid, etc.); polycaprolactone polyol obtained by reaction of the above polyhydric alcohol with ε-caprolactone; polycarbonate polyol (for example, obtained by reaction of 1,6-hexanediol and diphenyl carbonate) 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, adducts of these isocyanate compounds, or these Polymers of isocyanate and the like can be mentioned.

Examples of the hydroxy(meth)acrylate compounds include pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, hydroxyethyl (meth)acrylate, ) acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, dimethylolcyclohexyl mono (meth)acrylate, hydroxycaprolactone (meth)acrylate and the like. Among them, pentaerythritol tri(meth)acrylate and dipentaerythritol penta(meth)acrylate are preferable from the viewpoint of hardness.

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 (hexafunctional), Arakawa Chemical Industries: Beamset 577 (hexafunctional), Taisei Fine Chemicals: 8UX-015A (15 functional) and Shin-Nakamura Chemical: U15HA (15 functionality) and the like.

The compound having an alkenyl group used in the release layer of the present invention is not particularly limited, and general compounds can be suitably used. Examples of commercially available products include Nippon Kasei Co., Ltd.: TAIC (registered trademark) triallyl isocyanurate (trifunctional), Shikoku Kasei Co., Ltd.: LDAIC (bifunctional), TA-G (tetrafunctional), DD-1. (tetrafunctional) and the like.

When using a radical-curable substance in the release layer of the present invention, it is preferable to use a radical initiator in order to advance the reaction. As the radical initiator, both a thermal radical initiator and a photoradical initiator can be preferably used, but it is preferable to use a photoradical initiator because the amount of heat during processing can be suppressed. One type or two or more types of initiators may be used, and a photoradical initiator and a thermal radical initiator may be used at the same time.

The radical initiator is not particularly limited and general ones can be used. Specific examples 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-hydroxycyclohexylphenyl ketone, benzyldiphenylsulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, β-chloranthraquinone, (2,4,6-trimethylbenzyldiphenyl)phosphine oxide, 2-benzothiazole-N,N-diethyldithiocarbamate and the like.

As the radical initiator, α-hydroxyalkylphenones and α-aminoalkylphenones, which are said to be particularly excellent in surface curability, can be preferably used to suppress oxygen inhibition. Examples of α-hydroxyalkylphenones include 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]-phenyl}- 2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl- and 1-propan-1-one. Examples of α-aminoalkylphenones include 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1,2-methyl-1-(4-methylthiophenyl)-2-morpholinopro pan-1-one, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholyl)phenyl]-1-butanone and the like.

When a photoradical initiator is used, a sensitizer can be added to promote absorption of active energy rays and further improve curability. The sensitizer is not particularly limited and commonly used ones, but anthracene derivatives and naphthalene derivatives are suitable. One type or two or more types of sensitizers may be used.

The amount of the radical initiator added is preferably 0.1% by mass or more and 20% by mass or less, and is 0.5% by mass or more and 10% by mass or less, based on the total solid content in the release layer. is more preferable, and it is most preferable that it is 1% by mass or more and 8% by mass or less. When the content is 0.1% by mass or more, the amount of generated radicals becomes insufficient, which is preferable because there is no risk of insufficient curing. When the amount is 20 parts by mass or less, the amount of the radical initiator residue contained in the release layer is reduced, which is preferable because it is possible to suppress deterioration of releasability and transfer to the ceramic green sheet to be molded.

The amount of the sensitizer to be added is preferably 0.1 to 5 times the weight of the radical photoinitiator. More preferably, it is 0.1 to 2 times. When it is larger than 0.1 times, it is preferable because a sufficient sensitizing effect can be obtained. If it is smaller than 5 times, it is preferable because there is no possibility that the absorption of the active energy ray by the photoradical initiator will be inhibited and the amount of generated radicals will be insufficient.

The cationic curable substance used as the binder component (a) is not particularly limited and can be a general one, but is preferably a vinyl ether compound or a cyclic ether compound. Among them, an oxetane compound or a compound having an epoxy group is preferably used. is preferred. Examples of oxetane compounds include aliphatic, aromatic and cycloaliphatic compounds. Examples of the compound having an epoxy group include glycidyl ether type, glycidyl amine type, glycidyl ester type epoxy, and alicyclic epoxy. Glycidyl ether type epoxy and alicyclic epoxy are particularly preferred, and the reaction It is most preferable to use cycloaliphatic epoxies from the viewpoint of compatibility. Examples of glycidyl ether type epoxy compounds include aromatic glycidyl ethers typified by bisphenol type epoxy resins and cresol novolac type epoxy resins, and aliphatic glycidyl ethers typified by hydrogenated type A glycidyl ethers and butyl glycidyl ethers. be done. Examples of the alicyclic epoxy include those into which an ester skeleton, a dicyclopentadiene skeleton, a fluorene skeleton, an ε-caprolactone skeleton, or the like is introduced, and may have other skeletons.

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

A commercially available one can also be used as the oxetane compound. Examples of commercially available products include Aron Oxetane (registered trademark) OXT-101, 212 (manufactured by Toagosei Co., Ltd., monofunctional) OXT221, OXT-121 (manufactured by Toagosei Co., Ltd., bifunctional), ETERNACOL (registered trademark) ) EHO, OXMA (manufactured by Ube Industries, monofunctional) OXTP, OXBP (manufactured by Ube Industries, bifunctional) and the like.

The release layer in the present invention preferably has a high crosslink density in order to suppress corrosion of the release layer by an organic solvent. Therefore, any of polymers, oligomers, and monomers may be used as the cationic curable substance, but it is particularly preferable to use a monomer because the number of cross-linking points per unit mass increases and the cross-linking density can be increased.

When using a cationic curable substance for the release layer in the present invention, it is preferable to use an acid generator in order to promote the cationic polymerization reaction. The acid generator to be used is not particularly limited and a common one is used, but it is preferable to use a photoacid generator that generates acid under active energy ray irradiation, because the amount of heat during processing can be suppressed. . A release layer with a high cross-linking density that can suppress the corrosion of organic solvents can be obtained by using a common acid such as a sulfonic acid or a carboxylic acid. The surface of the release layer may become rough due to heat shrinkage of the raw material and deterioration of smoothness. In addition, metal salt-based, phosphate ester-based, and block-type acid generators in which the acid site is blocked can also be used. Most preferred from

From the viewpoint of reactivity, it is preferable to use a salt composed of an onium ion and a non-nucleophilic anion as the photoacid generator. Alternatively, an organometallic complex typified by an iron arene complex or a carbocation salt typified by tropylium may be used, and an anthracene derivative or a phenol substituted with an electron-withdrawing group such as pentafluorophenol may also be used. .

When a salt composed of an onium ion and a non-nucleophilic anion is used as a photoacid generator, the onium ion can be, for example, iodonium, sulfonium or ammonium. As the organic group of the onium ion, triaryl, diaryl (monoalkyl), monoaryl (dialkyl), trialkyl may be used, and benzophenone or 9-fluorene may be introduced, or other organic groups may be used. good. As non-nucleophilic anions, hexafluorophosphate, hexafluoroantimonate, hexafluoroborate, and tetra(pentafluorophenyl)borate are preferably used. Alternatively, tetra(pentafluorophenyl)gallium ions, anions in which some fluorine anions are replaced with perfluoroalkyl groups or organic groups, or other anion components may be used.

When the photoacid generator is used, a sensitizer can be added to increase the reactivity of the polymerization reaction and further suppress corrosion of the release layer by the organic solvent. The sensitizer is not particularly limited and commonly used ones, but anthracene derivatives and naphthalene derivatives are suitable. One type or two or more types of sensitizers may be used.

The amount of the photoacid generator added to the coating liquid containing the release layer-forming composition is 0.1 to 10% by mass, more preferably 0.5%, based on the total solid content in the release layer. ~8% by mass. More preferably, it is 1 to 5% by mass. A content of 0.1% by mass or more is preferable because there is no risk of insufficient curing due to an insufficient amount of generated acid. In addition, when the amount is 10% by mass or less, the amount of generated acid becomes appropriate, and the amount of acid transferred to the ceramic green sheet to be molded can be suppressed, which is preferable.

(Silsesquioxane component (b))
The present inventors have found that a release layer containing a binder component (a) and a certain amount of silsesquioxane component (b) exhibits excellent peelability from an ultra-thin ceramic green sheet. I found out. The content of the silsesquioxane component (b) contained in the release layer is from 0.01% by mass to 0.01% by mass when the mass of the total solid content constituting the release layer-forming composition is 100% by mass. It is preferably 60% by mass, more preferably 0.01% by mass to 30% by mass, even more preferably 0.01% by mass to 25% by mass, and 0.01% by mass to 20% by mass. is most preferred. It is preferable that the content of the silsesquioxane component (b) is 0.01% by mass or more because the peelability is excellent. When the content is 60% by mass or less, there is no risk of lowering the crosslink density, and excellent hardness and peelability are obtained, which is preferable.

The silsesquioxane component (b) in the present invention refers to a silsesquioxane having a unit composition formula of [(RSiO _3/2 ) _n ]. At this time, R refers to an organic functional group, which is not particularly limited, and non-reactive functional groups such as a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, a polyorganosiloxane group, a hydroxyl group, a carboxyl group, an amino group. , thiol groups, epoxy groups, alicyclic epoxy groups, oxetanyl groups, vinyl ether groups, acryloyl groups, methacryloyl groups, and alkenyl groups. R is not limited to one type, and may have two or more types of organic functional groups per molecule.

The silsesquioxane component (b) is chemically stable and has excellent solvent resistance as compared with silicone-based release additives represented by polyorganosiloxane. Therefore, there is no risk that the release layer will be eroded by the organic solvent used when molding the ceramic green sheet or when printing the internal electrodes, and the release layer can be made excellent in releasability.

In addition, the silsesquioxane component (b) has a more rigid skeleton than silicone-based mold release agents represented by polyorganosiloxane, and has characteristics similar to those of inorganic materials. Therefore, compared to silicone-based release agents, the surface hardness of the release layer can be increased, making it difficult for the release layer to deform when the ultra-thin ceramic green sheet is peeled off, exhibiting excellent release properties.

Examples of the skeleton structure of silsesquioxane include a random structure, a complete cage structure, a ladder structure, an incomplete cage structure, and the like. The silsesquioxane component (b) in the present invention may be a silsesquioxane having only one skeleton structure or a mixture of silsesquioxanes having two or more skeleton structures. A mixture of silsesquioxanes having two or more skeleton structures is preferred from the viewpoints of ease of handling, ease of handling, and cost.

The method for synthesizing the silsesquioxane component (b) is not particularly limited. An example is a method of hydrolyzing and condensing a trifunctional silane in the presence of an acidic or basic catalyst. Two or more types of trifunctional silanes may be used for the hydrolysis/condensation reaction, or tetrafunctional silanes having one or more types of hydrolyzable groups may be used. Incidentally, the trifunctional silane preferably has the organic functional group R described above.

The weight average molecular weight (Mw) of the silsesquioxane component (b) used in the present invention is preferably 1,000 to 100,000, more preferably 1,000 to 50,000. A weight-average molecular weight of 1,000 or more is preferable because of excellent solvent resistance. When the molecular weight is 100,000 or less, there is no risk of an extreme increase in viscosity or crystallization, and handleability is facilitated, which is preferable.

In the present invention, by using the silsesquioxane component (b), excellent peelability from the ultra-thin layer ceramic green sheet can be obtained. Thus, even better releasability can be obtained. It is most preferable to use polydimethylsiloxane groups as the polyorganosiloxane groups. In addition, the silsesquioxane component (b) having a polyorganosiloxane group in the molecule described in this specification includes the case where the polyorganosiloxane exists at the end of the molecule and the case where it exists in the molecular skeleton. there is

Silsesquioxane component (b) preferably has a reactive functional group capable of cross-linking with binder (a). By using the silsesquioxane component (b) having a reactive group that can be crosslinked with the binder (a), it is incorporated into the crosslinked structure of the binder (a) during curing to form a release layer with a higher surface hardness. It is preferable because In addition, Si-containing components such as the silsesquioxane component (b) are less likely to be transferred to the ceramic green sheets, which is preferable because there is no risk of lowering the reliability of the ceramic capacitor.

When a melamine-based substance is used as the binder component (a), the silsesquioxane component (b) contains one or more reactive functional groups selected from hydroxyl groups, carboxyl groups, amino groups, hydrosilyl groups, alkoxyl groups, epoxy groups, and the like. Having a group is more preferable from the viewpoint of reactivity with melamine-based substances, and it is particularly preferable to have at least one reactive functional group selected from a hydroxyl group, a carboxyl group, an amino group and a hydrosilyl group.

When a radically curable substance is used as the binder component (a), the silsesquioxane component (b) has at least one reactive functional group selected from acryloyl groups, methacryloyl groups, alkenyl groups, thiol groups and maleimide groups. From the viewpoint of reactivity with the radical curing substance, it is preferable to have at least one reactive functional group selected from acryloyl groups, methacryloyl groups, alkenyl groups and thiol groups.

When a cationic curable material is used as the binder component (a), the silsesquioxane component (b) has at least one reactive functional group selected from an epoxy group, an alicyclic epoxy group, an oxetanyl group and a vinyl ether group. is preferable from the viewpoint of reactivity with the cationic curable substance, and it is particularly preferable to have at least one reactive functional group selected from an epoxy group, an alicyclic epoxy group and an oxetanyl group.

As the silsesquioxane component (b), commercially available products can also be suitably used. Commercially available examples include Compoceran (registered trademark) SQ106, 107, 109 (manufactured by Arakawa Chemical Industries, Ltd., containing a thiol group), Compoceran (registered trademark) SQ506, 508, 510, 511 (manufactured by Arakawa Chemical Industries, Ltd.). Kogyo Co., Ltd., containing epoxy groups), AC-SQ TA100 (manufactured by Toagosei Co., Ltd., containing acryloyl groups), MAC-SQ TM-100 (manufactured by Toagosei Co., Ltd., containing methacryloyl groups), AC-SQ SI-20 (Toagosei manufactured by Toagosei Co., Ltd., containing polydimethylsiloxane group and acryloyl group), MAC-SQ SI-20 (manufactured by Toagosei Co., Ltd., containing polydimethylsiloxane group and methacryloyl group), OX-SQ TX100 (manufactured by Toagosei Co., Ltd., containing oxetanyl group), OX-SQ SI-20 (manufactured by Toagosei Co., Ltd., containing polydimethylsiloxane group and oxetanyl group), PSS-octa[(1,2-epoxy-4-ethylcyclohexyl)dimethylsiloxy] substituted product (manufactured by SIGMA-ALDRICH, alicyclic epoxy group-containing), PSS-octavinyl-substituted product (manufactured by SIGMA-ALDRICH, vinyl group-containing), and the like.

(other ingredients)
The release layer in the present invention may contain particles having a particle size of 1 μm or less, but from the viewpoint of pinhole generation, it is preferable not to contain particles that form protrusions.

Additives such as an adhesion improver and an antistatic agent may be added to the release layer in the present invention as long as the effects of the present invention are not impaired. In order to improve adhesion to the substrate, 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.

(Other Matters Concerning Release 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. , more preferably 0.01 to 1.5 μm, more preferably 0.01 to 1.0 μm. In particular, when a release layer is provided on the surface layer A of a polyester film having a surface layer A that does not substantially contain inorganic particles, the thinner the thickness of the release layer, the lower the coating agent cost. This is preferable because it is economical and can suppress the occurrence of curling. Specifically, it is preferably 0.8 μm or less, more preferably 0.5 μm or less. When the thickness of the release layer is thicker than 0.01 μm, sufficient release performance can be obtained, which is preferable. When the thickness is less than 2.0 μm, curling of the release film due to cure shrinkage is less likely to occur, which is preferable because there is no risk of unevenness in the thickness of the ceramic green sheet or deterioration of electrode printing accuracy.

The surface of the release layer of the release film of the present invention is desirably flat so as not to cause defects in the ceramic green sheet coated and molded thereon, and the area surface average roughness (Sa) is 7 nm or less. Preferably. Further, it is more preferable that the above Sa is satisfied and the maximum projection height (P) on the release layer surface is 100 nm or less. It is particularly preferred that the region surface average roughness (Sa) is 5 nm or less, and most preferred is that the maximum projection height (P) is 80 nm or less. If the area surface roughness is 7 nm or less, defects such as pinholes do not occur when the ceramic green sheets are 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. It can be said that the smaller the maximum projection height (P) is, the more preferable it is, but the maximum projection height (P) may be 1 nm or more, or 3 nm or more.

The release film of the present invention preferably has a peeling force of 0.3 mN/mm or more and 4.0 mN/mm or less when peeling the ceramic green sheet, and preferably 0.5 mN/mm or more and 3.0 mN/mm. It is more preferably 0.5 mN/mm or more and 2.0 mN/mm or less. A peeling force of 0.3 mN/mm or more is preferable because the peeling force is too light to lift the ceramic green sheet during transportation. When the peel force is 4.0 mN/mm or less, the ceramic green sheet is not damaged during peeling, and thus there is no possibility of causing defects, which is preferable.

It is preferable that the release film of the present invention has higher solvent resistance because it suppresses corrosion of the release layer by an organic solvent such as toluene during ceramic sheet processing or electrode printing. Solvent resistance can be confirmed by evaluating the difference in the surface state of the release layer before and after the release film is immersed in an organic solvent. As the organic solvent, it is preferable to use toluene, which is used for general ceramic slurries and conductive pastes, assuming ceramic green sheet processing and electrode printing. An example of a method for evaluating the surface state of the release layer is the evaluation based on the contact angle, and the smaller the change in the contact angle of the release layer surface before and after immersion in toluene, the better.

There are no particular restrictions on the type of liquid stripper used when measuring the contact angle, and water, bromonaphthalene, ethylene glycol, and the like can be suitably used. Most preferably, diiodomethane is used.

When diiodomethane was used as the liquid sample used to measure the contact angle, the diiodomethane contact angle _θ1 on the release layer surface and the contact angle θ on the release layer surface after the release film was immersed in toluene at room temperature for 5 minutes. The smaller the value of the difference in ₂ (θ ₁ −θ ₂ ) is, the better the solvent resistance of the surface of the release layer is. 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 angle is 3.0° or less, erosion of the release layer by an organic solvent during processing of the ceramic green sheet or printing of electrodes is suppressed, and there is no risk of an increase in peeling force or loss of uniformity of peeling, which is preferable. The difference (θ ₁ - _{θ 2} ) between the diiodomethane contact angle θ ₁ on the release layer surface and the contact angle θ ₂ on the release layer surface after immersing the release film in toluene at room temperature for 5 minutes is most preferably 0°. , the absolute value may be 0.05° or more, or 0.1° or more.

In the release film of the present invention, the higher the hardness of the release layer surface, the less likely the release layer is deformed when the ultra-thin ceramic green sheet is peeled off, and the release layer can be peeled off with a low and uniform force. preferable. In addition, the higher the hardness, the less likely the release layer is scratched during transport by rolls, etc., which is preferable because there is no risk of partial increase in release force or unevenness in the thickness of the ceramic green sheet. The hardness of the release layer surface can be evaluated by the degree of scratching (scratch resistance) when the release layer surface is rubbed with steel wool. The degree of scratching (scratch resistance) can be evaluated by the number of scratches formed when the release layer is rubbed with steel wool. The smaller the number of scratches, the higher the hardness of the release layer surface, which is preferable.

In the release film of the present invention, it is preferable that the amount of the release agent component transferred to the ceramic green sheet after peeling is as small as possible. The migration amount of the release agent component was measured by simulating PVB, one of the binder components contained in the ceramic green sheet, on the release film, molding it, and measuring the Si intensity of the release layer before and after peeling. It can be evaluated by measuring with a line. More specifically, when the Si strength of the release layer surface is Si (before) and the Si strength of the release surface of the release film after coating and peeling the PVB sheet is Si (after), Si ( The value of (before) - Si (after) was taken as the migration amount. The migration amount at this time is preferably 0.20 Kcps or less, more preferably 0.10 Kcps or less. If the migration amount is 0.20 Kcps or less, it is preferable because there is no risk of lowering the reliability of the ceramic capacitor.

(Method for forming release layer)
In the present invention, the method of forming the release layer is not particularly limited, and a coating solution in which a composition containing a release substance or the like is dissolved or dispersed is spread by coating or the like on one surface of the polyester film as the base material. Then, after removing the solvent and the like by drying and drying by heating, a method of curing by irradiation with active energy rays or heat is used.

When a thermosetting substance is used for the binder component (a), the drying temperature during solvent drying and heat curing is preferably 100° C. or higher and 180° C. or lower, and preferably 100° C. or higher and 160° C. or lower. More preferably, the temperature is 100° C. or higher and 140° 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 planarity of the film is maintained, and the possibility of causing unevenness in the thickness of the ceramic green sheet is small, 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 possibility of causing unevenness in the thickness of the ceramic green sheet is further reduced, which is particularly preferred. When the temperature is higher than 100°C, the curing reaction does not proceed sufficiently, and there is no risk of lowering the elastic modulus of the release layer, which is preferable.

When an active energy ray-curable substance (i.e., a radical-curable substance or a cationic-curable substance) is used as the binder component (a), the drying temperature for solvent drying is preferably 50° C. or higher and 100° C. or lower. It is more preferably 60°C or higher and 95°C or lower. The heating time is preferably 30 seconds or less, more preferably 20 seconds or less. When the temperature is 100° C. or less, the thermal load on the film is suppressed, the poor appearance due to heat shrinkage of the film is less likely to occur, and the possibility of unevenness in the thickness of the ceramic green sheet is small, which is preferable. When the temperature is 95° C. or lower, the thermal load on the film is further reduced, the film can be processed without impairing the flatness of the film, and the possibility of causing unevenness in the thickness of the ceramic green sheet is further reduced, which is particularly preferred. If the temperature is higher than 50°C, drying of the diluent solvent used in coating becomes insufficient, and the risk of process contamination or the like disappearing, which is preferable.

As the active energy ray used for curing the active energy ray-curable substance, 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 in terms of integrated light amount, more preferably 30 to 200 mJ/cm ² . It is preferable to set it to 30 mJ/cm ² or more because the curing of the active energy ray-curable substance progresses sufficiently. It is preferable to make the release film 300 mJ/cm ² or less because the processing speed can be improved and the release film can be produced economically.

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 adjusting the surface tension as described above, the wettability 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 coating 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. As for the amount to be added, it is preferable to add about 10 to 80% by mass based on the entire coating liquid.

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

(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 alternately provided 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 face 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 for producing such a laminated ceramic capacitor. For example, it is manufactured as follows. First, using the release film of the present invention as a carrier film, a ceramic slurry for forming a ceramic body is applied and dried. As for the thickness of the ceramic green sheet, an ultra-thin product with a thickness of 0.2 to 1.0 μm is required. A conductive layer for forming the first or second internal electrode is printed on the coated and dried ceramic green sheet. Ceramic green sheets, ceramic green sheets printed with conductive layers for forming first internal electrodes, and ceramic green sheets printed with conductive layers for forming second internal electrodes are appropriately laminated and pressed. Thus, a mother laminate is obtained. The mother laminate is divided into a plurality of pieces to produce raw ceramic bodies. 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.

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

(Intrinsic viscosity of polyester resin (dl/g))
Measured at 30° C. using a mixed solvent of phenol (60% by mass) and 1,1,2,2-tetrachloroethane (40% by mass) as a solvent in accordance with JIS K 7367-5.

(Base film thickness)
Using a millitron (electronic microindicator), 4 pieces of 5 cm square samples were cut out from 4 arbitrary points of the film to be measured, 5 points each (20 points in total) were measured, and the average value was taken as the thickness.

(Release layer thickness)
The cut release film was embedded in a resin and cut into ultrathin slices using an ultramicrotome. Then, using a JEOL JEM2100 transmission electron microscope, direct observation was performed at a magnification of 20,000, and the film thickness of the release layer was measured from the observed TEM image.

(Area surface roughness Sa, maximum protrusion height P)
These are values measured under the following conditions using a non-contact surface profile measurement system (VertScan R550H-M100 manufactured by Ryoka Systems Co., Ltd.). The area surface average roughness (Sa) was the average value of 5 measurements, and the maximum protrusion height (P) was measured 7 times, and the maximum value of the 5 measurements excluding the maximum and minimum values was used.
(Measurement condition)
・Measurement mode: WAVE mode ・Objective lens: 10x ・0.5×Tube lens ・Measurement area: 936 μm×702 μm
(analysis conditions)
・Surface correction: Quaternary correction ・Interpolation processing: Complete interpolation

(Evaluation of pinholes in ceramic green sheets)
A composition composed of the following materials was stirred and mixed, and dispersed with zirconia beads having a diameter of 0.5 mm for 30 minutes using a bead mill to obtain a ceramic slurry.
Toluene 76.3 parts by mass Ethanol 76.3 parts by mass Barium titanate (HPBT-1 manufactured by Fuji Titanium Co., Ltd.) 35.0 parts by mass Polyvinyl butyral (Eslec (registered trademark) BM-S manufactured by Sekisui Chemical Co., Ltd.) 3.5 parts by mass DOP (dioctyl phthalate) 1.8 parts by mass Next, the release surface of the obtained release film sample was coated with an applicator so that the dried ceramic green sheet had a thickness of 0.8 µm, and the mixture was heated at 90°C for 2 hours. After drying, the release film was peeled off to obtain a ceramic green sheet. In the central region of the obtained ceramic green sheet in the film width direction, light was applied from the opposite side of the ceramic slurry-coated surface in a range of 25 cm ² , and the occurrence of pinholes that can be seen through light transmission was observed. judged visually. The measurement was performed 5 times and the average value was adopted.
◎: No pinholes ○: Almost no pinholes (reference: 2 or less pinholes per measurement area)
△: Pinholes occur (reference: 3 or more pinholes per measurement area, 5 or less)
×: Many pinholes are generated

(Peelability evaluation of ceramic green sheet)
A composition consisting of the following materials was stirred and mixed, and dispersed with zirconia beads having a diameter of 0.5 mm using a bead mill for 60 minutes to obtain a ceramic slurry.
Toluene 38.3 parts by mass Ethanol 38.3 parts by mass Barium titanate (HPBT-1 manufactured by Fuji Titanium Co., Ltd.) 64.8 parts by mass Polyvinyl butyral 6.5 parts by mass (Eslec (registered trademark) BM-S manufactured by Sekisui Chemical Co., Ltd. )
DOP (dioctyl phthalate) 3.3 parts by mass Next, the release surface of the release film sample was coated with an applicator so that the dried ceramic green sheet had a thickness of 1 μm, and dried at 90° C. for 2 minutes. A sheet was cast on a release film. The release film with the ceramic green sheet thus obtained was cut into a piece having a width of 30 mm and a length of 80 mm to obtain a sample for peel strength measurement. After static elimination using a static eliminator (manufactured by Keyence Corporation, SJ-F020), using a peel tester (manufactured by Kyowa Interface Science Co., Ltd., VPA-3), a peeling angle of 90 degrees, a peeling temperature of 25 ° C., a peeling speed of 10 m / It peeled off at min. As for the peeling direction, a double-sided adhesive tape (manufactured by Nitto Denko Co., Ltd., No. 535A) was attached to the SUS plate attached to the peel tester, and the ceramic green sheet side was adhered 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 value of the peel force at the peel distance of 20 mm to 70 mm was calculated, and the value was defined as the peel force. The measurement was carried out a total of 5 times, and the average value of the peel strength was used for evaluation. Judgment was made according to the following criteria from the numerical value of the obtained peel strength.
⊚: The peeling force was 2.0 mN/mm or less, which was very light.
◯: The peel force was greater than 2.0 mN/mm, and peeled with a relatively light force of 3.0 mN/mm or less.
Δ: The peeling force was greater than 3.0 mN/mm, and could be peeled off with a light force of 4.0 mN/mm or less.
x: A peeling force greater than 4.0 mN/mm was required.

(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 on the release film was adopted, and the average value of the values measured five times was adopted.

(Contact angle after immersion in toluene)
A release film used for 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 surface facing downward. The immersed release film was taken out, and air-dried for 15 minutes with the release surface facing up, and then vacuum-dried overnight at 25°C. The release film thus obtained after immersion in toluene was measured by the same method as the method for measuring the contact angle.

(Evaluation of contact angle change)
When the initial diiodomethane contact angle on the release layer surface before immersion in toluene measured by the above method is θ ₁ , and the diiodomethane contact angle on the release layer surface after immersion in toluene is θ ₂ , θ ₁ - _{θ 2} The absolute value was taken as the change in contact angle before and after immersion in toluene. The contact angle change was evaluated according to the following criteria.
◎: |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°

(Evaluation of scratch resistance)
Steel wool (Bonstar (registered trademark) No. 0000, manufactured by Nippon Steel Wool Co., Ltd.) was attached to a metal pedestal having a weight of 200 g and a size of 700 mm ² to prepare a steel wool evaluation jig. Using this jig, the release surface side of the release film was rubbed back and forth 10 times while applying a load of 200 g so that the release surface side of the release film was in contact with the steel wool. A 2×2 cm area in the center of the rubbed surface was observed under the reflection of a fluorescent light, and the number of visually visible scratches was evaluated. The number of scratches was determined and evaluated according to the following criteria.
◎: number of scratches ≤ 1 ○: 1 < number of scratches ≤ 10 △: 10 < number of scratches ≤ 20 x: 20 < number of scratches

(Evaluation of amount of Si migration)
A composition consisting of the following materials was stirred and mixed to obtain a PVB solution.
Toluene 45.0 parts by mass Ethanol 45.0 parts by mass Polyvinyl butyral (S-lec BM-S manufactured by Sekisui Chemical Co., Ltd.) 10.0 parts by mass Then, the PVB sheet after drying using an applicator is applied to the release surface of the release film sample. After coating to a thickness of 10 μm and drying at 90° C. for 1 minute, the release film is peeled off, and the surface of the peeled PVB sheet that was in contact with the release film (release layer) and the PVB sheet are coated. The Si intensity of the release layer of the previous release film was measured with a fluorescent X-ray device (ZSX Primus2 manufactured by Rigaku) to quantify the amount of Si transferred. The measurement conditions of the fluorescent X-ray device were as follows.
Analysis line: Si-KA, target: Rh4.0kW
Tube voltage: 50 kV, Tube current: 60 mA
Filter: OUT, Attenuator: 1/1, Slit: S4, Analysis crystal: PET
Detector: PC, PHA conditions: 100 (lower limit) - 300 (upper limit)
Measurement diameter: 30 mm, atmosphere: vacuum The amount of silicone transferred is Si (before), which is the Si strength of the release surface of the release film before coating the PVB sheet, and the release film after coating and peeling the PVB sheet. Si (rear) is the Si intensity of the release surface of the mold release surface, and the value obtained by subtracting Si (rear) from Si (before) is taken as the amount of Si transfer. Judgment was made according to the following criteria from the obtained numerical value of the amount of Si transferred.
A: 0.04 kcps or less A: Greater than 0.04 kcps and less than 0.10 kcps.
Δ: greater than 0.10 kcps and less than 0.20 kcps.
×: 0.20 kcps or more

(Preparation of polyethylene terephthalate pellets (PET (I)))
As the esterification reactor, a continuous esterification reactor comprising 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) was adjusted to 2 tons/hour, EG (ethylene glycol) was adjusted to 2 mol per 1 mol of TPA, and antimony trioxide was adjusted to give an amount of Sb atoms of 160 ppm relative to the produced PET. It was continuously supplied to the first esterification reactor of the reaction apparatus and reacted at 255° C. for an average residence time of 4 hours under normal pressure. 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 into the second esterification reaction can. 8% by mass of EG is supplied to the produced PET, and an EG solution containing magnesium acetate tetrahydrate in an amount such that the Mg atom is 65 ppm relative to the produced PET, and the P atom is 40 ppm relative to the produced PET. An EG solution containing a certain amount of TMPA (trimethyl phosphate) was added and reacted at normal pressure at 260° C. for an average residence time of 1 hour. Next, the reaction product in the second esterification reactor was continuously taken out of the system and supplied to the third esterification reactor, and was subjected to 39 MPa (400 kg/cm ² ) using a high-pressure disperser (manufactured by Nippon Seiki Co., Ltd.). 0.2% by mass of porous colloidal silica having an average particle size of 0.9 μm, which has been subjected to dispersion treatment for an average number of 5 passes at a pressure of , and 1% by mass of ammonium salt of polyacrylic acid per calcium carbonate. While adding 0.4% by mass of synthetic calcium carbonate with a diameter of 0.6 μm as a 10% EG slurry, the mixture was reacted at normal pressure at 260° C. for an average residence time of 0.5 hours. The esterification reaction product produced in the third esterification reaction vessel was continuously supplied to a three-stage continuous polycondensation reactor for polycondensation to sinter stainless steel fibers having a 95% cut diameter of 20 μm. After filtration with a filter, ultrafiltration was performed, the product was extruded into water, and after cooling, it was cut into chips to obtain PET chips having an intrinsic viscosity of 0.60 dl/g (hereinafter abbreviated as PET (I)). . The lubricant content in the PET chip was 0.6% by mass.

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

(Manufacturing method of laminated film X1)
As the laminated film X1, E5101 (Toyobo Ester (registered trademark) film, manufactured by Toyobo Co., Ltd.) having a thickness of 25 μm was used. E5101 has a structure in which inorganic particles are contained in the film. The Sa of the surface layer A of the laminated film X1 was 24 nm, and the Sa of the surface layer B was 24 nm.

(Production of laminated film X2)
After the PET chips are dried, they are melted at 285° C. and melted at 290° C. by a separate melt extruder extruder to form a filter made of sintered stainless steel fibers with a 95% cut diameter of 15 μm and a filter with a 95% cut diameter of 15 μm. Two-stage filtration of sintered stainless steel particles is performed, and they are combined in the feed block to form PET (I) as surface layer B (anti-separate surface side layer) and PET (II) as surface layer A. (release surface side layer), extruded (casting) into a sheet at a speed of 45 m / min, electrostatically adhered on a casting drum at 30 ° C. by an electrostatic adhesion method, cooled, and intrinsic viscosity An unstretched polyethylene terephthalate sheet having a .DELTA..times.0.59 dl/g was obtained. The layer ratio was adjusted so that PET(I)/PET(II)=60%/40% by calculation of the discharge amount of each extruder. Then, the 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. due to the speed difference between the rolls. After that, it was led to a tenter and stretched 4.2 times in the transverse direction at 140°C. It was then heat treated at 210° C. in a heat setting zone. After that, a 2.3% relaxation treatment was applied in the transverse direction at 170° C. to obtain a biaxially stretched polyethylene terephthalate film X2 having a thickness of 25 μm. The Sa of the surface layer A of the obtained film X2 was 2 nm, and the Sa of the surface layer B was 29 nm.

(Example 1)
A coating solution having the composition shown below was applied on the surface layer A of the laminated film X1 using a wire bar so that the thickness of the release layer after drying was 1.0 μm, and dried at 90° C. for 15 seconds. After that, ultraviolet light (LC6B, H bulb, manufactured by Heraeus) was irradiated with an accumulated light amount of 50 mJ/cm ² to obtain a release film for producing an ultra-thin ceramic green sheet. A ceramic slurry was applied to the obtained release film, and the surface roughness of the release layer, releasability, pinholes, scratch resistance, Si migration property, and solvent resistance were evaluated, and good evaluation results were obtained. was taken.
Methyl ethyl ketone 45.00 parts by mass Isopropyl alcohol 45.00 parts by mass Binder component (a): 10-functional urethane acrylate 9.50 parts by mass (product name: Shiko (registered trademark) UV-1700B, manufactured by Nippon Synthetic Chemical Co., Ltd., solid content 100 mass%)
Silsesquioxane component (b): PDMS, acryloyl group-containing silsesquioxane
0.10 parts by mass
(Product name: AC-SQ SI-20, manufactured by Toagosei Co., Ltd., solid content 100% by mass)
Radical initiator: 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one 0.40 parts by mass (product name : Omnirad 127, manufactured by IGM Resins, solid content 100% by mass)

(Example 2)
In the same manner as in Example 1, except that the silsesquioxane component (b) was changed to PDMS, a methacryloyl group-containing silsesquioxane (MAC-SQ SI-20, manufactured by Toagosei Co., Ltd., solid content 100% by mass). A release film for the production of ultra-thin ceramic green sheets was obtained.

(Example 3)
Ultra-thin in the same manner as in Example 1 except that the silsesquioxane component (b) was changed to an acryloyl group-containing silsesquioxane (AC-SQ TA-100, manufactured by Toagosei Co., Ltd., solid content 100% by mass) A release film for the production of layered ceramic green sheets was obtained.

(Example 4)
Ultra-thin in the same manner as in Example 1 except that the silsesquioxane component (b) was changed to a methacryloyl group-containing silsesquioxane (MAC-SQ TM-100, manufactured by Toagosei Co., Ltd., solid content 100% by mass) A release film for the production of layered ceramic green sheets was obtained.

(Example 5)
Example except that the silsesquioxane component (b) was changed to a thiol group-containing silsesquioxane (Compoceran (registered trademark) SQ107, manufactured by Arakawa Chemical Industries, Ltd., solid content 72% by mass) to adjust the blending amount. A release film for producing an ultra-thin ceramic green sheet was obtained in the same manner as in 1.

(Example 6)
Ultra-thin layer ceramic in the same manner as in Example 1 except that the binder component (a) was changed to a hexafunctional urethane acrylate (Shiko (registered trademark) UV-7600B, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., solid content 100% by mass) A release film for green sheet production was obtained.

(Example 7)
Mold release for ultrathin layer ceramic green sheet production in the same manner as in Example 1 except that the binder component (a) was changed to a hexafunctional acrylate (A-DPH, manufactured by Shin-Nakamura Chemical Co., Ltd., solid content 100% by mass). got the film.

(Example 8)
Ultra-thin layer ceramic green was prepared in the same manner as in Example 1, except that the binder component (a) was changed to a trifunctional allyl compound (Taiku (registered trademark), triisocyanurate, manufactured by Nippon Kasei Chemical Co., Ltd., solid content 100% by mass). A release film for sheet production was obtained.

(Example 9)
A release film for producing an ultra-thin ceramic green sheet was obtained in the same manner as in Example 1, except that the coating liquid was changed to the composition shown below.
Methyl ethyl ketone 45.00 parts by mass Isopropyl alcohol 45.00 parts by mass Binder component (a): 7.60 parts by mass of 10-functional urethane acrylate (product name: Shiko (registered trademark) UV-1700B, manufactured by Nippon Synthetic Chemical Co., Ltd., solid content 100 mass%)
Silsesquioxane component (b): PDMS, acryloyl group-containing silsesquioxane
2.00 parts by mass
(Product name: AC-SQ SI-20, manufactured by Toagosei Co., Ltd., solid content 100% by mass)
Radical initiator: 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one 0.40 parts by mass (product name : Omnirad 127, manufactured by IGM Resins, solid content 100% by mass)

(Example 10)
A release film for producing an ultra-thin ceramic green sheet was obtained in the same manner as in Example 1, except that the coating liquid was changed to the composition shown below.
Methyl ethyl ketone 45.00 parts by mass Isopropyl alcohol 45.00 parts by mass Binder component (a): 10-functional urethane acrylate 5.60 parts by mass (product name: Shiko (registered trademark) UV-1700B, manufactured by Nippon Synthetic Chemical Co., Ltd., solid content 100 mass%)
Silsesquioxane component (b): PDMS, acryloyl group-containing silsesquioxane
4.00 parts by mass
(Product name: AC-SQ SI-20, manufactured by Toagosei Co., Ltd., solid content 100% by mass)
Radical initiator: 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one 0.40 parts by mass (product name : Omnirad 127, manufactured by IGM Resins, solid content 100% by mass)

(Example 11)
A release film for producing an ultra-thin ceramic green sheet was obtained in the same manner as in Example 1, except that the coating liquid was changed to the composition shown below.
Methyl ethyl ketone 45.00 parts by mass Isopropyl alcohol 45.00 parts by mass Binder component (a): 10-functional urethane acrylate 3.60 parts by mass (product name: Shiko (registered trademark) UV-1700B, manufactured by Nippon Synthetic Chemical Co., Ltd., solid content 100 mass%)
Silsesquioxane component (b): PDMS, acryloyl group-containing silsesquioxane
6.00 parts by mass
(Product name: AC-SQ SI-20, manufactured by Toagosei Co., Ltd., solid content 100% by mass)
Radical initiator: 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one 0.40 parts by mass (product name : Omnirad 127, manufactured by IGM Resins, solid content 100% by mass)

(Example 12)
A release film for producing an ultra-thin ceramic green sheet was obtained in the same manner as in Example 1, except that the coating liquid was changed to the composition shown below.
Methyl ethyl ketone 44.80 parts by mass Toluene 44.80 parts by mass Binder component (a): Bifunctional alicyclic epoxy monomer 9.50 parts by mass (product name: Celoxide (registered trademark) 2021P, manufactured by Daicel Corporation, solid content 100% by mass )
Silsesquioxane component (b): PDMS, oxetanyl group-containing silsesquioxane
0.10 parts by mass
(Product name: AC-SQ SI-20, manufactured by Toagosei Co., Ltd., solid content 100% by mass)
Photoacid generator: Diphenyl[4-(phenylthio)phenyl]sulfonium hexafluoroantimonate 0.80 parts by mass (product name: CPI (registered trademark)-101A, manufactured by San-Apro Co., Ltd., solid content 50% by mass)

(Example 13)
Ultra-thin in the same manner as in Example 12, except that the silsesquioxane component (b) was changed to an oxetanyl group-containing silsesquioxane (OX-SQ TX-100, manufactured by Toagosei Co., Ltd., solid content 100% by mass) A release film for the production of layered ceramic green sheets was obtained.

(Example 14)
A release film for producing an ultrathin ceramic green sheet was obtained in the same manner as in Example 12, except that the silsesquioxane component (b) was changed to an alicyclic epoxy group-containing silsesquioxane.

(Example 15)
An ultra-thin layer ceramic was prepared in the same manner as in Example 12, except that the binder component (a) was changed to a tetrafunctional alicyclic epoxy monomer (Epoled (registered trademark) GT-401, manufactured by Daicel Corporation, solid content 100% by mass). A release film for green sheet production was obtained.

(Example 16)
Ultrathin layer ceramic green was prepared in the same manner as in Example 12, except that the binder component (a) was changed to a bifunctional oxetane compound (Aron Oxetane (registered trademark) OX-221, manufactured by Toagosei Co., Ltd., solid content 100% by mass). A release film for sheet production was obtained.

(Example 17)
A release film for producing an ultra-thin ceramic green sheet was obtained in the same manner as in Example 1, except that the coating liquid was changed to the composition shown below.
Methyl ethyl ketone 44.80 parts by mass Toluene 44.80 parts by mass Binder component (a): Bifunctional alicyclic epoxy monomer 7.60 parts by mass (product name: Celoxide (registered trademark) 2021P, manufactured by Daicel Corporation, solid content 100% by mass )
Silsesquioxane component (b): PDMS, oxetanyl group-containing silsesquioxane
2.00 parts by mass
(Product name: OX-SQ SI-20, manufactured by Toagosei Co., Ltd., solid content 100% by mass)
Photoacid generator: Diphenyl[4-(phenylthio)phenyl]sulfonium hexafluoroantimonate 0.80 parts by mass (product name: CPI (registered trademark)-101A, manufactured by San-Apro Co., Ltd., solid content 50% by mass)

(Example 18)
A release film for producing an ultra-thin ceramic green sheet was obtained in the same manner as in Example 1, except that the coating liquid was changed to the composition shown below.
Methyl ethyl ketone 44.80 parts by mass Toluene 44.80 parts by mass Binder component (a): Bifunctional alicyclic epoxy monomer 5.60 parts by mass (product name: Celoxide (registered trademark) 2021P, manufactured by Daicel Corporation, solid content 100% by mass )
Silsesquioxane component (b): PDMS, oxetanyl group-containing silsesquioxane
4.00 parts by mass
(Product name: OX-SQ SI-20, manufactured by Toagosei Co., Ltd., solid content 100% by mass)
Photoacid generator: Diphenyl[4-(phenylthio)phenyl]sulfonium hexafluoroantimonate 0.80 parts by mass (product name: CPI (registered trademark)-101A, manufactured by San-Apro Co., Ltd., solid content 50% by mass)

(Example 19)
A release film for producing an ultra-thin ceramic green sheet was obtained in the same manner as in Example 1, except that the coating liquid was changed to the composition shown below.
Methyl ethyl ketone 44.80 parts by mass Toluene 44.80 parts by mass Binder component (a): Bifunctional alicyclic epoxy monomer 3.60 parts by mass (product name: Celoxide (registered trademark) 2021P, manufactured by Daicel Corporation, solid content 100% by mass )
Silsesquioxane component (b): PDMS, oxetanyl group-containing silsesquioxane
6.00 parts by mass
(Product name: OX-SQ SI-20, manufactured by Toagosei Co., Ltd., solid content 100% by mass)
Photoacid generator: Diphenyl[4-(phenylthio)phenyl]sulfonium hexafluoroantimonate 0.80 parts by mass (product name: CPI (registered trademark)-101A, manufactured by San-Apro Co., Ltd., solid content 50% by mass)

(Example 20)
A coating solution having the composition shown below was applied on the surface layer A of the laminated film X1 using a wire bar so that the thickness of the release layer after drying was 1.0 μm, and dried at 120° C. for 15 seconds. A release film for the production of ultra-thin ceramic green sheets was obtained.
Methyl ethyl ketone 45.00 parts by mass Toluene 45.00 parts by mass Binder (a): Hexamethoxymethyl melamine 9.50 parts by mass (product name: N,N,N',N',N'',N''-hexakis ( Methoxymethyl) melamine, manufactured by Tokyo Chemical Industry Co., Ltd., solid content 100%)
Silsesquioxane component (b): PDMS, OH-containing silsesquioxane
0.10 parts by mass Acid catalyst (4-methylbenzoic acid) 0.40 parts by mass

(Example 21)
A release film for producing an ultra-thin ceramic green sheet was obtained in the same manner as in Example 1, except that the release layer was coated on the surface layer A of the laminated film X2 so that the thickness of the release layer was 0.8 μm. .

(Example 22)
A release film for producing an ultra-thin ceramic green sheet was obtained in the same manner as in Example 12, except that the release layer was coated on the surface layer A of the laminated film X2 so that the thickness of the release layer was 0.5 μm. .

(Example 23)
A release film for producing an ultra-thin ceramic green sheet was obtained in the same manner as in Example 12, except that the release layer was coated on the surface layer A of the laminated film X2 so that the thickness of the release layer was 0.2 μm. .

(Comparative example 1)
A release film for producing an ultra-thin ceramic green sheet was obtained in the same manner as in Example 1, except that the coating solution was changed to the composition shown below.
Methyl ethyl ketone 45.00 parts by mass Isopropyl alcohol 45.00 parts by mass Binder component (a): 10-functional urethane acrylate 9.50 parts by mass (product name: Shiko (registered trademark) UV-1700B, manufactured by Nippon Synthetic Chemical Co., Ltd., solid content 100 mass%)
Polyether-modified PDMS 0.10 parts by mass (product name: BYK UV-3510, manufactured by Big Chemie Japan, solid content 100% by mass)
Radical initiator: 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one 0.40 parts by mass (product name : Omnirad 127, manufactured by IGM Resins, solid content 100% by mass)

(Comparative example 2)
A release film for producing an ultra-thin ceramic green sheet was obtained in the same manner as in Example 1, except that the coating solution was changed to the composition shown below.
Methyl ethyl ketone 45.00 parts by mass Isopropyl alcohol 45.00 parts by mass Binder component (a): Hexafunctional acrylate 9.50 parts by mass (product name: A-DPH, manufactured by Shin-Nakamura Chemical Co., Ltd., solid content 100% by mass)
Acryloyl group-containing polyether-modified PDMS 0.10 parts by mass (product name: BYK UV-3500, manufactured by Big Chemie Japan, solid content 100% by mass)
Radical initiator: 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one 0.40 parts by mass (product name : Omnirad 127, manufactured by IGM Resins, solid content 100% by mass)

(Comparative Example 3)
A release film for producing an ultra-thin ceramic green sheet was obtained in the same manner as in Example 1, except that the coating solution was changed to the composition shown below.
Methyl ethyl ketone 44.80 parts by mass Toluene 44.80 parts by mass Binder component (a): Bifunctional alicyclic epoxy monomer 9.50 parts by mass (product name: Celoxide (registered trademark) 2021P, manufactured by Daicel Corporation, solid content 100% by mass )
0.10 parts by mass of epoxy-modified PDMS (product name: X-22-173DX, manufactured by Shin-Etsu Silicone Co., Ltd., solid content 100% by mass)
Photoacid generator: Diphenyl[4-(phenylthio)phenyl]sulfonium hexafluoroantimonate 0.80 parts by mass (product name: CPI (registered trademark)-101A, manufactured by San-Apro Co., Ltd., solid content 50% by mass)

(Comparative Example 4)
A release film for producing an ultra-thin ceramic green sheet was obtained in the same manner as in Example 20, except that the coating liquid having the composition shown below was used.
Methyl ethyl ketone 45.00 parts by mass Toluene 45.00 parts by mass Binder (a): Hexamethoxymethyl melamine 9.50 parts by mass (product name: N,N,N',N',N'',N''-hexakis ( Methoxymethyl) melamine, manufactured by Tokyo Chemical Industry Co., Ltd., solid content 100%)
0.10 parts by mass of epoxy-modified PDMS (product name: X-22-173DX, manufactured by Shin-Etsu Silicone Co., Ltd., solid content 100% by mass)
Acid catalyst (4-methylbenzoic acid) 0.40 parts by mass

(Comparative Example 5)
A release film for producing an ultra-thin ceramic green sheet was obtained in the same manner as in Example 1, except that the coating solution was changed to the composition shown below.
Methyl ethyl ketone 45.00 parts by mass Isopropyl alcohol 45.00 parts by mass Binder component (a): Hexafunctional acrylate 9.60 parts by mass (product name: A-DPH, manufactured by Shin-Nakamura Chemical Co., Ltd., solid content 100% by mass)
Radical initiator: 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one 0.40 parts by mass (product name : Omnirad 127, manufactured by IGM Resins, solid content 100% by mass)

(Comparative Example 6)
A release film for producing an ultra-thin ceramic green sheet was obtained in the same manner as in Example 1, except that the coating solution was changed to the composition shown below.
Methyl ethyl ketone 44.80 parts by mass Toluene 44.80 parts by mass Binder component (a): Bifunctional alicyclic epoxy monomer 9.60 parts by mass (product name: Celloxide (registered trademark) 2021P, manufactured by Daicel Corporation, solid content 100% by mass )
Photoacid generator: Diphenyl[4-(phenylthio)phenyl]sulfonium hexafluoroantimonate 0.80 parts by mass (product name: CPI (registered trademark)-101A, manufactured by San-Apro Co., Ltd., solid content 50% by mass)

The release film for producing a ceramic green sheet of the present invention has a highly smooth release layer surface, high hardness, and excellent solvent resistance. Therefore, the release layer is not eroded during ceramic green sheet processing or electrode printing, and even when an ultra-thin ceramic green sheet with a thickness of 1 μm or less is peeled off, the peeling force is low and uniform. It is possible to mold a ceramic green sheet with less

Claims (8)

A release film provided with a release layer directly or via another layer on at least one side of the polyester film,
The release layer is formed by curing a composition containing a binder component (a) and a silsesquioxane component (b),
the binder component (a) is a radically curable substance,
The silsesquioxane component (b) has at least one reactive functional group selected from acryloyl groups, methacryloyl groups, alkenyl groups and thiol groups in the molecule,
The radical curable substance includes acrylate, methacrylate, urethane acrylate, acrylamide, allyl compound, methallyl compound, and maleimide compound alone or in combination of two or more,
When oligomers are included as the acrylate and the methacrylate,
The oligomer is selected from polyfunctional (meth)acrylate oligomers, polyester acrylate-based oligomers, epoxy acrylate-based oligomers, polyether acrylate-based oligomers, and polybutadiene acrylate-based oligomers.
Release film for manufacturing ceramic green sheets. 2. The release film for producing a ceramic green sheet according to claim 1, wherein the content of the silsesquioxane component (b) with respect to the total solid content of the composition is 0.01% by mass to 60% by mass. 3. The release film for producing a ceramic green sheet according to claim 1, wherein the silsesquioxane component (b) has a polyorganosiloxane group in its molecule. 2. The release film for producing a ceramic green sheet according to claim 1, wherein the release layer surface has an area surface average roughness (Sa) of 7 nm or less. 2. The release film for producing a ceramic green sheet according to claim 1, wherein the binder component (a) contains a hexafunctional or higher compound. The polyester film has a surface layer A that does not substantially contain inorganic particles and an opposite surface layer B that contains inorganic particles, a release layer is provided on the surface layer A, and the surface layer The release film for producing a ceramic green sheet according to claim 1, wherein the inorganic particles contained in B are silica particles and/or calcium carbonate particles, and the total amount of inorganic particles contained in the surface layer B is 5000 to 15000 ppm. A method for producing a ceramic green sheet having a thickness of 0.2 μm to 1.0 μm, wherein the release film for producing a ceramic green sheet according to claim 1 is used. A method for manufacturing a ceramic capacitor employing the method for manufacturing a ceramic green sheet according to claim 7.