JPWO2019073875A1 - Release film for manufacturing ceramic green sheets - Google Patents

Abstract

[PROBLEMS] To peel even an ultra-thin layer product with a thickness of 1 μm or less by maintaining high smoothness on the surface of the release layer and making the force applied when peeling the ceramic green sheet from the release film low and uniform To provide a release film for manufacturing a ceramic green sheet that sometimes does not damage the ceramic green sheet. A release film in which a release layer is provided on the surface layer A of a polyester film having a surface layer A substantially free of inorganic particles, wherein the release layer is a cationic curable substance. A release film for producing a ceramic green sheet obtained by curing a composition containing a binder a containing 1 and one or more release agents b. [Selection figure] None

Description

  The present invention relates to a release film for producing a ceramic green sheet. By suppressing erosion of a release layer by an organic solvent during ceramic sheet processing or internal electrode printing, an increase in peeling force or uniformity of peeling can be achieved. The present invention relates to a release film for producing a ceramic green sheet that is not likely to be damaged.

  Conventionally, a release film in which a polyester film is used as a base material and a release layer is laminated thereon has been used for molding ceramic green sheets such as a laminated ceramic capacitor and a ceramic substrate. In recent years, the thickness of the ceramic green sheet tends to be reduced as the multilayer ceramic capacitor is reduced in size and capacity. The ceramic green sheet is molded by applying a slurry containing a ceramic component such as barium titanate and a binder resin on a release film and drying. After the electrode is printed on the molded ceramic green sheet and peeled from the release film, the ceramic green sheet is laminated, pressed, fired, and an external electrode is applied to produce a multilayer ceramic capacitor. When molding a ceramic green sheet on the release layer surface of a polyester film, there is a problem that minute protrusions on the surface of the release layer affect the molded ceramic green sheet and easily cause defects such as repelling and pinholes. there were. Therefore, a technique for realizing a release layer surface having excellent flatness has been developed (see, for example, Patent Document 1).

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

  In recent years, it has been found that the surface of the release layer becomes smooth by using a radical curable substance that reacts under irradiation of active energy rays. At the same time, it has been found that the silicone component or the cured product thereof contained in the release layer is also excellent in releasability from the ceramic sheet (for example, see Patent Document 2).

  However, according to the method described in Patent Document 2, when processing in the air, there is a problem that the release layer surface is poorly cured due to the influence of oxygen inhibition due to radical polymerization reaction. When poor curing occurs on the surface of the release layer, the release layer is eroded by the organic solvent during ceramic green sheet processing and internal electrode printing, which increases the peel force and impairs the release uniformity. There was a risk of damaging the sheet.

  In addition, the radical polymerization reaction has a problem that curl is easily generated in the release film due to large shrinkage in curing. When curl occurs in the release film, the transportability of the release film is deteriorated and the electrode printing accuracy is lowered, which may cause defects.

JP 2000-117899 A International Publication No. 2013/145864

As a result of intensive studies in view of the above circumstances, the present invention maintains high smoothness of the surface of the release layer, and reduces the force applied when the ceramic green sheet is peeled from the release film, thereby reducing the thickness. Therefore, an object of the present invention is to provide a release film for producing a ceramic green sheet that does not cause damage to the ceramic green sheet at the time of peeling even if it is an ultra-thin layer product of 1 μm or less.

That is, the present invention has the following configuration.
1. A release film in which a release layer is provided on the surface layer A of a polyester film having a surface layer A substantially free of inorganic particles, wherein the release layer contains a cationic curable substance. And a release film for producing a ceramic green sheet obtained by curing a composition containing at least one release agent b.
2. The mold release for producing the ceramic green sheet according to the first aspect, wherein a difference between the diiodomethane contact angle θ _{1 on the} surface of the release layer and the diiodomethane contact angle θ _{2 on} the release layer surface after immersion in toluene is 3.0 ° or less as an absolute value the film.
3. The release film for producing a ceramic green sheet according to the first or second aspect, wherein the at least one release agent b is a compound containing a silicone skeleton.
4). The release film for producing a ceramic green sheet according to any one of the first to third aspects, wherein the binder a containing a cationic curable substance contains 80% by mass or more in the total solid content of the release layer.
5. The ceramic according to any one of the first to fourth, wherein the binder a containing a cationic curable substance contains at least one compound selected from a compound having an alicyclic epoxy group and a compound having an oxetane ring in the molecule. Release film for green sheet manufacturing.
6). The release film for producing a ceramic green sheet according to any one of the first to fifth aspects, wherein at least one of the release agents b is silicone containing an alicyclic epoxy group.
7. The separation for manufacturing a ceramic green sheet according to any one of the first to sixth aspects, wherein the average surface roughness (Sa) of the release layer surface is 7 nm or less and the maximum protrusion height (P) is 100 nm or less. Mold film.
8). It is a manufacturing method of the ceramic green sheet which has thickness of 0.2 micrometer-1.0 micrometer, Comprising: The manufacturing method of the ceramic green sheet using the release film for ceramic green sheet manufacture in any one of Claims 1-7.
9. A method for producing a ceramic capacitor, which employs the method for producing a ceramic green sheet according to the eighth aspect.

  According to the present invention, since there is no erosion of the release layer by the organic solvent during ceramic sheet processing or internal electrode printing, the release film for producing a ceramic green sheet does not have a risk of increasing the peeling force or deteriorating the uniformity of peeling. Can be provided.

  The present inventors used a polyester film with a controlled surface roughness, provided a release layer on one side, and contained a binder a composed of a cationic curable substance and at least one release agent b in the release layer. It has been found that by using the constitution, a release film for producing a ceramic green sheet excellent in releasability can be provided without the possibility that the release layer is eroded by an organic solvent. Further, the present inventors have found that a release film that does not easily curl and does not cause a decrease in electrode printing accuracy can be provided because a cationically curable substance with little curing shrinkage is used. Hereinafter, the present invention will be described in detail.

  The release film for producing a ceramic green sheet of the present invention has a surface layer A substantially free of inorganic particles on at least one surface of a polyester film, and contains at least a cationic curable substance on the surface layer A. It is preferable that a release layer formed by curing a composition containing a binder a and one or more release agents b is laminated. Since the cationic curable substance is not inhibited from curing by oxygen, there is no possibility of causing poor curing of the surface of the release layer even in the air, and erosion of the release layer by the organic solvent can be suppressed. In addition, since the cationic curable substance has a small curing shrinkage, curling is difficult to occur, and there is no possibility that the electrode printing accuracy is lowered. In addition, the cation curable substance used here refers to a compound in which a cation generated in a reaction system becomes an active species and a curing reaction proceeds.

  The release layer in the present invention is preferably less eroded by the organic solvent. The erosion of the release layer can be confirmed by evaluating the difference in the surface state of the release layer before and after the release film is immersed in an organic solvent. As the organic solvent used for the immersion, it is preferable to use toluene used for a general ceramic slurry assuming a ceramic green sheet manufacturing process. An example of a method for evaluating the surface state of the release layer is evaluation by contact angle, and the smaller the contact angle change of the release layer surface before and after immersion in toluene, the better.

  The type of droplet used for measuring the contact angle is not particularly limited, and water, bromonaphthalene, ethylene glycol, and the like can be suitably used, but diiodomethane in which the difference in the surface state of the release layer is more noticeable. Most preferably, is used.

When diiodomethane is used as a droplet used for measuring the contact angle, the contact angle θ ₁ of the release layer surface and the contact angle θ ₂ of the release layer surface after the release film is immersed in toluene for 5 minutes at room temperature. The smaller the absolute value of the difference (θ ₁ −θ ₂ ), the better the solvent resistance of the release layer surface. 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 due to the organic solvent during ceramic green sheet processing or internal electrode printing is suppressed, and there is no fear that increase in peeling force or peeling uniformity may be impaired. The smaller the difference (θ ₁ −θ ₂ ) between the diiodomethane contact angle θ ₁ of the release layer surface and the contact angle θ ₂ of the release layer surface after the release film is immersed in toluene at room temperature for 5 minutes, it is preferably 0 Although it is most preferable, it may be 0.05 ° or more as an absolute value.

(Polyester film)
The polyester constituting the polyester film used as the base material in the present invention is not particularly limited, and a polyester film generally used as a base material for a release film can be used, but preferably, A crystalline linear saturated polyester composed of an aromatic dibasic acid component and a diol component is preferable. For example, polyethylene terephthalate, polyethylene-2,6-naphthalate, polybutylene terephthalate, polytrimethylene terephthalate, or a resin thereof. A copolymer having a constituent component as a main component is more preferable, and a polyester film formed from polyethylene terephthalate is particularly preferable. In polyethylene terephthalate, the repeating unit of ethylene terephthalate is preferably 90 mol% or more, more preferably 95 mol% or more, and other dicarboxylic acid components and diol components may be copolymerized in a small amount, but from the viewpoint of cost. Those produced only from terephthalic acid and ethylene glycol are preferred. Moreover, you may add a well-known additive, for example, antioxidant, a light stabilizer, a ultraviolet absorber, a crystallizing agent, etc. within the range which does not inhibit the effect of the release film of this invention. The polyester film is preferably a biaxially oriented polyester film for reasons such as high bidirectional elasticity.

  The intrinsic viscosity of the polyethylene terephthalate film is preferably 0.50 to 0.70 dl / g, and 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 breakage does not occur in the stretching process. On the other hand, when it is 0.70 dl / g or less, it is preferable because cutting property when cutting to a predetermined product width is good and dimensional defects do not occur. Moreover, it is preferable that the raw material is sufficiently vacuum-dried.

  The manufacturing method of the polyester film in this invention is not specifically limited, The method generally used conventionally can be used. For example, the polyester can be melted with an extruder, extruded into a film, cooled with a rotary cooling drum to obtain an unstretched film, and the unstretched film can be obtained by biaxial stretching. A biaxially stretched film can be obtained by a method of sequentially biaxially stretching a uniaxially stretched film in the longitudinal direction or the transverse direction in the transverse direction or the longitudinal direction, or a method of simultaneously biaxially stretching an unstretched film in the longitudinal direction and the transverse direction. I can do it.

  In this invention, it is preferable that the extending | stretching temperature at the time of extending | stretching a polyester film shall be more than the secondary transition point (Tg) of polyester. It is preferable to stretch 1 to 8 times, particularly 2 to 6 times in the longitudinal and lateral directions.

  It is preferable that the said polyester film is 12-50 micrometers in thickness, More preferably, it is 15-38 micrometers, More preferably, it is 19 micrometers-33 micrometers. If the thickness of the film is 12 μm or more, it is preferable that there is no risk of deformation due to heat during film production, processing steps, and molding. On the other hand, if the thickness of the film is 50 μm or less, the amount of the film discarded after use is not extremely increased, which is preferable in reducing the environmental load.

  The polyester film substrate may be a single layer or a multilayer of two or more layers, but preferably has 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 that can contain inorganic particles and the like on the opposite surface of the surface layer A that does not substantially contain inorganic particles. As the laminated structure, when the layer on the side to which the release layer is applied is the A layer, the opposite layer is the B layer, and the core layer other than these is the C layer, the layer structure in the thickness direction is the release layer / A / B, or a laminated structure such as a release layer / A / C / B. Of course, the C layer may have a plurality of layers. Further, 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 slipperiness for winding the film into a roll.

  In the polyester film substrate of the present invention, it is preferable that the surface layer A that forms the surface on which the release layer is applied does not substantially contain inorganic particles. At this time, the area surface average roughness (Sa) of the surface layer A is preferably 7 nm or less. When Sa is 7 nm or less, pinholes and the like are less likely to occur during molding of the laminated ultra-thin ceramic green sheet. Although it can be said that the region surface average roughness (Sa) of the surface layer A is preferably as small as possible, it may be 0.1 nm or more. Here, when providing the below-mentioned anchor coat layer etc. on the surface layer A, it is preferable that an inorganic particle is not included substantially in a coat layer, and the area | region surface average roughness (Sa) after coat layer lamination | stacking is the said range. It is preferable to enter. In the present invention, “substantially free of inorganic particles” means that the inorganic particles are not more than 50 ppm, preferably not more than 10 ppm, most preferably not more than the detection limit when inorganic elements are quantified by fluorescent X-ray analysis. Means quantity. This means that even if inorganic particles are not actively added to the film, contaminants derived from foreign substances, raw material resin, or dirt attached to the line or equipment in the film manufacturing process will be peeled off and mixed into the film. This is because there are cases.

  In the polyester film substrate of the present invention, the surface layer B that forms the surface opposite to the surface on which the release layer is applied preferably contains inorganic particles from the viewpoint of the slipperiness of the film and the ease of air removal, In particular, it is preferable to use silica particles and / or calcium carbonate particles. It is preferable that the inorganic particle content to be contained is 5,000 to 15,000 ppm in total in the surface layer B of the inorganic particles. At this time, it is preferable that the area | region surface average roughness (Sa) of the film of the surface layer B is the range of 1-40 nm. More preferably, it is the range of 5-35 nm. When the total of silica particles and / or calcium carbonate particles is 5000 ppm or more and Sa is 1 nm or more, when the film is rolled up, air can be released uniformly, and the winding shape is good and the flatness is good. This is suitable for the production of an ultrathin layer ceramic green sheet. In addition, when the total of silica particles and / or calcium carbonate particles is 15000 ppm or less and Sa is 40 nm or less, the lubricant is less likely to agglomerate and coarse protrusions cannot be formed, so the quality is stable when manufacturing ultra-thin ceramic green sheets. It is preferable.

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

  The average particle diameter 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 diameter of the inorganic particles is 0.1 μm or more, the slipperiness of the release film is good, which is preferable. Moreover, if an average particle diameter is 2.0 micrometers or less, there is no possibility that a pinhole may generate | occur | produce in the ceramic green sheet by the coarse particle of a mold release layer surface, and it is preferable.

  The surface layer B may contain two or more kinds of particles having different materials. Moreover, you may contain the same kind of particle | grains from which an average particle diameter differs.

  When the surface layer B does not contain particles, it is preferable that the surface layer B has a slipperiness with a coat layer containing particles. Although this coating layer is not specifically limited, It is preferable to provide with the in-line coating applied during film forming of a 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 is a region for the same reason as the surface average roughness (Sa) of the surface layer B described above. The surface average roughness (Sa) is preferably in the range of 1 to 40 nm. More preferably, it is the range of 5-35 nm.

  From the viewpoint of reducing pinholes, it is preferable not to use recycled materials or the like for the surface layer A, which is the layer on the side where the release layer is provided, in order to prevent the mixing of inorganic particles such as a lubricant.

  The thickness ratio of the surface layer A, which is the layer on the side where the release layer is provided, is preferably 20% to 50% of the total thickness of the base film. If it is 20% or more, the influence of particles contained in the surface layer B or the like is not easily received from the inside of the film, and the area surface average roughness Sa is easy to satisfy the above range, which is preferable. When the thickness is 50% or less of the total thickness of the base film, the use ratio of the recycled raw material in the surface layer B can be increased, and the environmental load is small.

  Further, from the viewpoint of economy, 50 to 90% by mass of film scraps and recycled materials for PET bottles can be used for layers other than the surface layer A (surface layer B or the aforementioned intermediate layer C). Even in this case, it is preferable that the type and amount of the lubricant contained in the B layer, the particle diameter, and the area surface average roughness (Sa) satisfy the above range.

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

(Release layer)
In the release layer in the present invention, a composition containing at least a binder a containing a cationic curable substance and at least one release agent b (additive for imparting peelability) is cured. Is preferred. The binder a containing a cationic curable substance can be crosslinked to form a highly elastic coating film. Increasing the elastic modulus of the release layer is preferable because the release layer does not deform and follow when peeling, and there is no risk of damaging the ceramic green sheet.

It can be added in addition to the resin and additives as long as the function of the present invention is not impaired. Here, in the present invention, the cationic curable substance is considered to have changed the structure of the compound in the state after being cured in the coating layer, but the changed structure itself resulting from the cationic curable substance itself. Since it is extremely difficult to accurately express and describe the above, as described above, “a composition containing a binder a containing a cationic curable substance and one or more release agents b is cured. It is expressed.

  The cation curable substance used for the release layer in the present invention is not particularly limited and can be a general one, but is preferably a vinyl ether compound or a cyclic ether compound, and among them, a compound containing an oxetane compound or an epoxy group. Is preferably used. Examples of oxetane compounds include aliphatic, aromatic and alicyclic compounds. Examples of the compound containing an epoxy group include glycidyl ether type, glycidyl amine type, glycidyl ester type epoxy and alicyclic epoxy, and in particular, glycidyl ether type epoxy and alicyclic epoxy are preferable, It is most preferable to use an alicyclic epoxy from the viewpoint of reactivity. Examples of the glycidyl ether type epoxy compound include aromatic glycidyl ethers typified by bisphenol type epoxy resins and cresol novolac type epoxy resins, aliphatic glycidyl ethers typified by hydrogenated A type glycidyl ether and butyl glycidyl ether, and the like. It is done. Examples of the alicyclic epoxy include those having an ester skeleton, a dicyclopentadiene skeleton, a fluorene skeleton, an ε-caprolactone skeleton and the like, and may have other skeletons.

  What is marketed can also be used as said alicyclic epoxy compound. Examples of commercially available products include Cyclomer (registered trademark) M100, Celoxide (registered trademark) 2000 (above, manufactured by Daicel Corp., monofunctional), Celoxide (registered trademark) 2021P, 2081 (above, manufactured by Daicel Corp., bifunctional) , Epolide (registered trademark) GT401 (manufactured by Daicel Corporation, tetrafunctional), EHPE (registered trademark) 3150 (manufactured by Daicel Corporation, multifunctional), and the like.

  As said oxetane compound, what is marketed can also be used. Examples of commercial products include Aron Oxetane (registered trademark) OXT-101, 212 (above, manufactured by Toagosei Co., Ltd., monofunctional) OXT221, OXT-121 (above, manufactured by Toagosei Co., Ltd., bifunctional), ETERNACOL (registered trademark) ) EHO, OXMA (above, Ube Industries, Ltd., monofunctional) OXTP, OXBP (above, Ube Industries, Ltd., bifunctional).

  The number of cation curable functional groups of the cation curable substance is not particularly limited, and may be one or two or more. In order to increase the crosslinking density of the release layer and improve the solvent resistance, the number of functional groups is preferably 2 or more. In addition, the cationic curable functional group may be introduced at any position within the terminal, side chain, or straight chain. In addition, the cation curable functional group shown here refers to a functional group that can be a crosslinking point in the cation curing reaction.

  One kind of the cationic curable substance may be used, or two or more kinds may be mixed and used. Although not particularly limited, the use of two or more types of cationic curable substances increases the crosslink density due to the complexity of the polymer network chain after the reaction, and suppresses erosion of the release layer by the organic solvent. Is preferable.

  When two or more kinds of cationic curable substances are used, although not limited by theory, it is preferable to use two kinds of cationic curable substances having different numbers of functional groups. By using those having different numbers of functional groups, a polymer network can be effectively constructed and a release layer having a high crosslinking density can be obtained. For example, a linear polymer is constructed with a bifunctional cationic curable material by mixing a cationic curable material with 2 functional groups and a polyfunctional cationic curable material with 3 or more functional groups. Since a crosslinked structure of polymer chains can be formed by entering a trifunctional or higher functional cationic curable substance into a part of the polymer chain, the crosslinking density can be improved.

  When two or more kinds of cationic curable substances are used, the optimal ratio is that the other curable substance is used in an amount of 0.1 to 50 parts by mass with respect to 100 parts by mass of one curable substance. More preferably, it is 0.5 to 20 parts by mass, and most preferably 1 to 10 parts by mass. When one curable substance is 0.1 part by mass or more, the amount taken into the crosslinked structure of the other curable substance is not extremely reduced, and the effect of increasing the crosslinking density can be sufficiently obtained. preferable. When one curable substance is used in an amount of 50 parts by mass or less, the crosslink structure between the curable substances is not dominant, and a complex polymer net chain obtained by mixing is formed, and the effect of increasing the crosslinking density Is preferable.

  The release layer in the present invention preferably has an increased crosslinking density in order to suppress erosion of the release layer by an organic solvent. For this reason, any of polymers, oligomers, and monomers may be used as the cationic curable substance. In particular, the use of a monomer is preferable because the number of crosslinking points per certain mass increases and the crosslinking density can be increased.

  In the release layer in the present invention, the cationic curable substance is preferably contained in an amount of 80% by mass or more and 99.9% or less, more preferably 90% by mass or more and 99.9%, based on the solid content of the entire release layer. % Or less, and more preferably 95% by mass or more and 99.9% or less. It is preferable to contain 80% by mass or more of the cationic curable substance because a high crosslinking density can be obtained by the cationic polymerization reaction and erosion of the release layer by the organic solvent can be suppressed. At this time, the solid content of the entire release layer is that the acid generator is decomposed under the drying process or irradiation with active energy rays, and it is difficult to accurately calculate a small amount of mass remaining in the release phase. Therefore, it is expressed as a total value of the solid contents of the binder component and the release agent.

(Acid generator)
In the release layer in the present invention, it is preferable to use an acid generator in order to advance the cationic polymerization reaction. The acid generator to be used is not particularly limited and a general one is used, but it is preferable to use a photoacid generator that generates an acid under irradiation of active energy rays because the amount of heat during processing can be suppressed. . Even by using a general acid such as a sulfonic acid type or a carboxylic acid type, it is possible to obtain a release layer having a high crosslinking density capable of suppressing erosion of an organic solvent, but a high processing temperature is required. There is a possibility that the surface of the release layer is roughened due to heat shrinkage of the raw fabric or a decrease in smoothness. In addition, metal salt-based, phosphate ester-based, and block-type acid generators in which acid sites are blocked can be used. However, using a photoacid generator for the reasons described above is a viewpoint of the amount of heat during processing. To most preferred.

  As the photoacid generator, it is preferable from the viewpoint of reactivity to use a salt comprising an onium ion and a non-nucleophilic anion. Further, an organometallic complex typified by an iron arene complex or a carbocation salt typified by tropylium may be used, or an anthracene derivative or a phenol substituted with an electron withdrawing group, for example, pentafluorophenol may be used. .

  When a salt composed of the onium ion and a non-nucleophilic anion is used as a photoacid generator, for example, iodonium, sulfonium, or ammonium can be used as the onium ion. As the organic group of the onium ion, triaryl, diaryl (monoalkyl), monoaryl (dialkyl), or trialkyl may be used. Even if benzophenone or 9-fluorene is introduced, other organic groups may be used. Good. As the non-nucleophilic anion, it is preferable to use hexafluorophosphorate, hexafluoroantimonate, hexafluoroborate, or tetra (pentafluorophenyl) borate. Further, tetra (pentafluorophenyl) gallium ions, anions obtained by replacing some of the fluorine anions with perfluoroalkyl groups or organic groups, or other anion components may be used.

  When the photoacid generator is used, by adding a sensitizer, the reactivity of the polymerization reaction can be increased, and erosion of the release layer by the organic solvent can be further suppressed. The sensitizer is not particularly limited and general ones are used, but anthracene derivatives and naphthalene derivatives are preferable. One type or two or more types of sensitizers may be used.

  It is preferable that the addition amount of the photo-acid generator to a coating liquid is 0.1-10 mass parts with respect to the mass sum total of the binder a which consists of a cationic curable substance contained in a mold release layer, and the mold release agent b. . More preferably, it is 0.5-8 mass parts. More preferably, it is 1-5 mass parts. The amount of 0.1 parts by mass or more is preferable because the amount of generated acid is insufficient and there is no fear of insufficient curing. Moreover, it is preferable for the amount to be 10 parts by mass or less because an appropriate amount of acid is generated and the amount of acid transferred to the ceramic green sheet to be molded can be suppressed.

  It is preferable that the addition amount of a sensitizer is 0.1-5 times as a mass with respect to a photo-acid generator. More preferably, it is 0.1 to 2 times. When it is larger than 0.1 times, there is no fear that a sufficient sensitizing effect cannot be obtained, which is preferable. When it is less than 5 times, the absorption of the active energy ray of the photoacid generator is inhibited, and there is no fear that the acid is not sufficiently generated.

(Release agent b)
As the release agent b (additive for imparting releasability) used in the release layer in the present invention, a silicone-based additive, a non-silicone-based additive such as a long-chain alkyl-based, fluorine-based, or the like is used. However, it is preferable to use a silicone-based additive from the viewpoint of peelability.

  A silicone-based additive is a material based on a polyorganosiloxane having an organic group attached to a siloxane bond, and is not particularly limited as long as the effects of the present invention can be obtained. can do. An acrylic resin or an alkyd resin having a polyorganosiloxane in the side chain can also be used. Among the polyorganosiloxanes, polydialkylsiloxanes can be preferably used. Among them, polydimethylsiloxane is more preferably used, and a polydimethylsiloxane having a functional group in a part thereof is more preferable. Having a functional group is preferable because intermolecular interactions such as a hydrogen bond and a cationic curable substance are easily developed and it is difficult to shift to a ceramic green sheet.

  Although it does not specifically limit as a functional group introduce | transduced into polydimethylsiloxane, A reactive functional group or a non-reactive functional group may be sufficient. In addition, the functional group may be introduced at one end of polydimethylsiloxane, or both ends or side chains may be used. Moreover, the position to be introduced may be one or plural.

  As a reactive functional group introduced into polydimethylsiloxane, a cyclic ether group, a hydroxy group, a mercapto group, a carboxyl group, a methacryloyl group, an acryloyl group, or the like can be used. Although not particularly limited, it is preferable to use a cyclic ether group, and in particular, the cationic curable substance contains a cationic curable functional group such as a glycidyl ether group, an alicyclic epoxy group, or an oxetane ring. This is preferable because it is incorporated into the cross-linked structure and it is difficult to shift to a ceramic green sheet. Among them, when an alicyclic epoxy group is contained, the compatibility with the binder component is also excellent, and thus the peelability is easily exhibited and is most preferable. As the non-reactive functional group, polyether group, alkyl group, fluoroalkyl group, long chain alkyl group, ester group, amide group, phenyl group, etc. can be used.

  In more detail, a preferable silicone-based additive is preferably a silicone-based additive having a cationic curable reactive group, and more preferably a silicone-based additive having an epoxy group. As the epoxy group, it is most preferable to use a silicone-based additive having an alicyclic epoxy group. More specifically, the structure of a silicone-based additive having an alicyclic epoxy group will be described. Polydimethylsiloxane containing an alicyclic epoxy group or an acrylic resin having a polydimethylsiloxane and an alicyclic epoxy group in the side chain. Is given as an example.

  It does not specifically limit as a silicone type additive used for this invention, The existing thing can be used. For example, as a commercially available silicone having a reactive functional group, X-22-170DX, X-22-3710, X-22-176DX, X-22-167B (manufactured by Shin-Etsu Chemical Co., Ltd.), BYK- Examples include UV3500, BYK-UV3505, BYK-UV3575 (manufactured by Big Chemie Japan). Examples of commercially available silicone additives having a cationic curable functional group include X-22-173BX, X-22-173DX, X-22-4741, X-22-9002 (manufactured by Shin-Etsu Chemical Co., Ltd.), etc. X-22-169B, KF-102, X-62-7629, X62-7660, X-62-7622 (Shin-Etsu Chemical Co., Ltd.), which are commercially available silicones having an alicyclic epoxy group. ), UV9300, UV9315, UV9430 (above, manufactured by Momentive Performance Materials), Silicolyse (registered trademark) UV Poly200, 201, 215 (above, made by Arakawa Chemical Industries, Ltd.), etc. .

  The fluorine-based additive is not particularly limited, and existing ones can be used. For example, those having a perfluoro group and those having a perfluoroether group can be suitably used. Examples of commercially available products include MegaFac (registered trademark) (manufactured by DIC), OPTOOL (registered trademark) (manufactured by Daikin Industries, Ltd.), and Fclear (registered trademark) (manufactured by Kanto Denka Kogyo).

  As the long-chain alkyl-based additive, a long-chain alkyl-modified resin can be used, and those having an alkyl group having about 8 to 20 carbon atoms in the side chain such as polyvinyl alcohol and acrylic resin are preferable. Moreover, it is a polymer which has (meth) acrylic acid ester as a main repeating unit, and the copolymer which contains a C8-C20 long-chain alkyl group in the transesterified part can also be used conveniently. Examples of commercially available products include Pyroyl (registered trademark) 1010, Pyroyl (registered trademark) 1050, Pyroyl (registered trademark) 1070 (Lion Specialty Chemicals), Tessfine (registered trademark) 305, Tessfine. (Registered trademark) 314 (manufactured by Hitachi Chemical Co., Ltd.).

  Further, two or more kinds of the above releasing agents may be mixed and used, but at least one releasing agent is preferably a silicone-based additive, and preferably a silicone having a cationic curable functional group. More preferred is silicone having an alicyclic epoxy group. It is preferable that at least one type of release agent is a silicone-based additive because a release layer having excellent peelability can be obtained.

  In the release layer in the present invention, the release agent b is preferably contained in an amount of 0.1% by mass or more and 20% by mass or less with respect to the solid content of the entire release layer. More preferably, they are 0.5 mass% or more and 10 mass% or less, More preferably, they are 0.5 mass% or more and 5 mass% or less. When the content is more than 0.1% by mass, releasability is imparted, and the peelability of the ceramic green sheet is not likely to deteriorate, which is preferable. When the amount is less than 20% by mass, a decrease in intermolecular interaction with the cationic curable substance is suppressed, and there is no possibility of causing a transition to a ceramic green sheet. At this time, the solid content of the entire release layer is that the acid generator is decomposed under the drying process or irradiation with active energy rays, and it is difficult to accurately calculate a small amount of mass remaining in the release phase. Therefore, it is expressed as a total value of the solid contents of the binder component and the release agent.

  The release layer in the present invention can contain particles having a particle size of 1 μm or less, but from the viewpoint of pinhole generation, except for a few impurities that are unintentionally mixed in unintentionally. In addition, it is preferable not to include particles that form protrusions such as particles, and it is particularly preferable that inorganic particles and organic particles are not included regardless of the type, particle size, or shape, regardless of solubility or insolubility. .

In the release layer of the present invention, an additive such as an adhesion improver or an antistatic agent may be added as long as the effect of the present invention is not impaired. In order to improve the adhesion to the substrate, it is also preferable that the polyester film surface is subjected to pretreatment such as anchor coating, corona treatment, plasma treatment, atmospheric pressure plasma treatment, etc. before providing the release coating layer.
(Characteristics of 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. Preferably, however, the thickness of the release coating layer after curing is in the range of 0.01 to 1.0 μm. More preferably, the thickness is 0.01 to 0.5 μm, more preferably 0.01 to 0.2 μm, and most preferably 0.02 to 0.1 μm. It is preferable that the thickness of the release layer is larger than 0.01 μm because sufficient peeling performance can be obtained. Moreover, since it is hard to produce the fault of curl as it is 1.0 micrometer or less, the active energy ray irradiation amount and heat amount required for hardening do not increase, there is no possibility of causing a reduction in processing speed, and from the economical aspect. Is also preferable.

  The surface of the release layer of the release film of the present invention is desirably flat so as not to cause defects in the ceramic green sheet applied and molded thereon, and the surface area average roughness (Sa) is 7 nm or less. Preferably there is. Further, it is more preferable that Sa is satisfied and the maximum protrusion height (P) on the surface of the release layer is 100 nm or less. It is particularly preferable if the area surface average roughness (Sa) is 5 nm or less and the maximum protrusion height is 80 nm or less. When the surface roughness of the region is 7 nm or less and the maximum protrusion height is 100 nm or less, there is no occurrence of defects such as pinholes when forming the ceramic green sheet, and the yield is favorable. It can be said that the smaller the surface average surface roughness (Sa), the better, but it may be 0.1 nm or more, or 0.3 nm or more. It can be said that the smaller the maximum protrusion height (P) is, the better, but it may be 1 nm or more, or 3 nm or more.

The release film of the present invention preferably has a peeling force of 0.5 mN / mm ² or more and 3.0 mN / mm ² or less when peeling the ceramic green sheet. More preferably, it is 0.8 mN / mm ² or more and 2.5 mN / mm ² or less. A peeling force of 0.5 mN / mm ² or more is preferable because the peeling force is too light and the ceramic green sheet is not likely to float during transportation. When the peeling force is 3.0 mN / mm ² or less, the ceramic green sheet is preferably not damaged during peeling.

In the release film of the present invention, the curl after heating at 100 ° C. for 15 minutes without applying tension is preferably 3 mm or less, more preferably 1 mm or less. Of course, it is also preferable not to curl at all. The thickness of 3 mm or less is preferable because a ceramic green sheet is molded and an electrode is printed so that curling is less and printing accuracy can be improved.
(Formation method of release layer)

  In the present invention, the method for forming the release layer is not particularly limited, and a coating solution in which a composition containing a releasable resin or the like is dissolved or dispersed is applied to one surface of the polyester film of the substrate by coating or the like. 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 curing using a photoacid generator, the heating temperature is preferably 50 ° C. or higher and 110 ° C. or lower, and more preferably 60 ° C. or higher and 100 ° C. or lower. The heating time is preferably 30 seconds or less, and more preferably 20 seconds or less. When the temperature is 110 ° C. or lower, the thermal load on the film can be suppressed, the appearance defect such as the heat shrinkage of the film is difficult to occur, and the possibility of causing uneven thickness of the ceramic green sheet is small. When the temperature is 100 ° 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 uneven thickness of the ceramic green sheet is further reduced, which is particularly preferable. When the temperature is higher than 50 ° C., the diluted solvent used for coating is sufficiently dried, and there is no possibility of causing process contamination and the like, which is preferable.

As active energy rays used for reacting a cationic curable substance with a photoacid generator, ultraviolet rays, electron beams, X-rays and the like can be used, but ultraviolet rays are preferred because they are easy to use. The amount of ultraviolet rays to be irradiated is preferably 10 to 1000 mJ / cm ² in terms of integrated light quantity, more preferably 15 to 500 mJ / cm ² , and further preferably 15 to 100 mJ / cm ² . Setting it to 10 mJ / cm ² or more is preferable because curing of the resin proceeds sufficiently. Since the speed at the time of a process can be improved by setting it as 1000 mJ / cm < ² > or less, a release film can be produced economically and it is preferable.

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

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

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

  Hereinafter, the present invention will be described in more detail with reference to examples. However, 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))
According to JIS K 7367-5, a mixed solvent of phenol (60% by mass) and 1,1,2,2-tetrachloroethane (40% by mass) was used as a solvent, and the measurement was performed at 30 ° C.

(Base film thickness)
Using a Millitron (electronic microindicator), four 5 cm square samples were cut from arbitrary four locations of the film to be measured, and each sample was measured at five points (20 points in total) to obtain the average value as the thickness.

(Film thickness of release layer)
The film cross section when the release film was cut to an arbitrary size was observed with a transmission electron microscope, and the calculated value was taken as the release layer thickness.

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

(Contact angle)
Using a contact angle meter (manufactured by Kyowa Interface Science Co., Ltd., fully automatic contact angle meter DM-701) under conditions of 25 ° C. and 50% RH, diiodomethane (droplet amount) 0.9 μL) droplets were prepared and their contact angles were measured. As the contact angle, the contact angle 30 seconds after dropping onto the release film was adopted, and the average value of the values measured five times was adopted.

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

(Evaluation of contact angle change)
Theta ₁ diiodomethane contact angle measurements toluene before immersion initial release layer surface by the _method, when the diiodomethane contact angle of the release layer surface after toluene immersion was theta _2, the theta ₁ - [theta] ₂ The absolute value was defined 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 °
Δ: 2.0 ° ≦ | θ ₁ −θ ₂ | ≦ 3.0 °
×: | θ ₁ −θ ₂ |> 3.0 °

(Ceramic green sheet pinhole evaluation)
The composition consisting of the following materials was stirred and mixed, and dispersed for 30 minutes using a bead mill having zirconia beads having a diameter of 0.5 mm as a dispersoid 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 3.5 parts by mass (Esreck (registered trademark) BM-S manufactured by Sekisui Chemical Co., Ltd.)
DOP (dioctyl phthalate) 1.8 parts by mass Next, the obtained release film sample was applied to the release surface using an applicator so that the dried slurry had a thickness of 0.8 μm and dried at 90 ° C. for 1 minute. Thereafter, the release film was peeled off to obtain a ceramic green sheet.
In the central region in the film width direction of the obtained ceramic green sheet, light was applied from the opposite side of the ceramic slurry coating surface within a range of 25 cm ² , and the occurrence of pinholes through which light was transmitted was observed. Visual judgment was made. The measurement was performed 5 times and the average value was adopted.
A: No occurrence of pinholes O: No occurrence of pinholes (Guideline: 2 or less pinholes per measurement area)
Δ: Pinholes are generated (reference: 5 pinholes per measurement area or less)
×: Many pinholes are generated

(Evaluation of peelability of ceramic green sheets)
A composition comprising the following materials was stirred and mixed, and dispersed for 60 minutes using a bead mill having zirconia beads having a diameter of 0.5 mm as a dispersoid 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 (Sekisui Chemical Co., Ltd. ESREC (registered trademark) BM-S)
3.3 parts by mass of DOP (dioctyl phthalate) Next, using an applicator, the resulting release film sample was coated so that the dried slurry had a thickness of 10 μm and dried at 90 ° C. for 2 minutes to give a ceramic. A green sheet was molded on the release film. The obtained release film with a ceramic green sheet was neutralized using a static eliminator (Keyence Co., SJ-F020), and then 30 mm wide using a high-speed peel tester (Tester Sangyo Co., Ltd., TE-701). Was peeled at a peeling angle of 90 degrees and a peeling speed of 10 m / min. Peeling was performed in a direction in which the ceramic green sheet surface was fixed and the release film surface was pulled. The stress applied at the time of peeling at this time was measured and taken as the peeling force.

(Curl evaluation of release film)
The release film sample was cut into a size of 10 cm × 10 cm, and heat-treated at 100 ° C. for 15 minutes in a hot air oven so that no tension was applied to the release film. Then, after taking out from oven and cooling to room temperature, the release film sample was set | placed on the glass plate so that a release surface might become upper. The height from the glass plate at this time to each corner apex was measured, and the curl was evaluated according to the following criteria.
A: Sum of each corner is 1 mm or less. O: Sum of each corner is larger than 1 mm and 3 mm or less.
(Triangle | delta): The sum total of each corner | angular part is larger than 3 mm, and is 10 mm or less.
X: The total curl of each corner is larger than 10 mm.

(Preparation of polyethylene terephthalate pellets (PET (I)))
As the esterification reaction apparatus, a continuous esterification reaction apparatus comprising a three-stage complete mixing tank having a stirrer, a partial condenser, a raw material charging port and a product outlet was used. TPA (terephthalic acid) is 2 tons / hour, EG (ethylene glycol) is 2 moles per mole of TPA, antimony trioxide is made into an amount that makes Sb atoms 160 ppm with respect to the produced PET, and these slurries are esterified. Was continuously supplied to the first esterification reactor of the chemical reaction apparatus, and allowed to react at 255 ° C. at an average residence time of 4 hours at 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 is distilled off from the first esterification reaction can in the second esterification reaction can. EG solution containing magnesium acetate tetrahydrate in an amount of 65 ppm of Mg atoms to the generated PET, and 40 ppm of P atoms to the generated PET An EG solution containing a certain amount of TMPA (trimethyl phosphate) was added and reacted at 260 ° C. at normal pressure for an average residence time of 1 hour. Next, the reaction product of the second esterification reaction can was continuously taken out of the system and supplied to the third esterification reaction can, and 39 MPa (400 kg / cm ² ) using a high pressure disperser (manufactured by Nippon Seiki Co., Ltd.). An average particle of 0.2 mass% of porous colloidal silica having an average particle diameter of 0.9 μm and an ammonium salt of polyacrylic acid adhered to 1 mass% of calcium carbonate, which was dispersed at an average number of treatments of 5 passes under the pressure of While adding 0.4% by mass of synthetic calcium carbonate having a diameter of 0.6 μm as an EG slurry of 10%, the reaction was carried out at 260 ° C. at an average residence time of 0.5 hours at normal pressure. The esterification reaction product produced in the third esterification reaction can was continuously supplied to a three-stage continuous polycondensation reaction apparatus to perform polycondensation, and sintered with a stainless steel fiber having a 95% cut diameter of 20 μm. After filtering with a filter, ultrafiltration was performed and extruded into water, and after cooling, it was cut into chips to obtain PET chips with an intrinsic viscosity of 0.60 dl / g (hereinafter referred to as PET (I)). . The lubricant content in the PET chip was 0.6% by mass.

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

(Manufacture of laminated film X1)
These PET chips were dried, melted at 285 ° C., melted at 290 ° C. with a separate melt extruder extruder, sintered with stainless steel fibers having a 95% cut diameter of 15 μm, and a 95% cut diameter Two-stage filtration of a 15 μm stainless steel particle-sintered filter is performed and merged in the feed block, PET (I) is surface layer B (reverse mold release side layer), and PET (II) is surface Laminated so as to be layer A (release surface side layer), extruded (casting) into a sheet at a speed of 45 m / min, electrostatically adhered and cooled on a casting drum at 30 ° C. by electrostatic adhesion method, An unstretched polyethylene terephthalate sheet having an intrinsic viscosity of 0.59 dl / g was obtained. The layer ratio was adjusted so that PET (I) / PET (II) = 60% / 40% in the discharge amount calculation of each extruder. Next, this unstretched sheet was heated with an infrared heater and then stretched 3.5 times in the longitudinal direction at a roll temperature of 80 ° C. due to the speed difference between the rolls. Thereafter, the film was guided to a tenter and stretched 4.2 times in the transverse direction at 140 ° C. Subsequently, it heat-processed at 210 degreeC in the heat setting zone. Thereafter, a relaxation treatment of 2.3% was performed at 170 ° C. in the transverse direction to obtain a biaxially stretched polyethylene terephthalate film X1 having a thickness of 31 μm. Sa of surface layer A of the obtained film X1 was 2 nm, and Sa of surface layer B was 28 nm.

(Manufacture of laminated film X2)
The layer configuration and stretching conditions similar to those of the laminated film X1 were not changed, but the thickness was adjusted by changing the speed during casting to obtain a biaxially stretched polyethylene terephthalate film X2 having a thickness of 25 μm. Sa of surface layer A of the obtained film X2 was 3 nm, and Sa of surface layer B was 29 nm.

(Laminated film X3)
As the laminated film X3, 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. Sa of surface layer A of laminated film X3 was 24 nm, and Sa of surface layer B was 24 nm.

(Example 1)
On the surface layer A of the laminated film X1, a coating solution having the following composition is applied using a wire bar so that the release layer thickness after drying is 50 nm and dried at 90 ° C. for 15 seconds. A release film for producing an ultra-thin ceramic green sheet was obtained by irradiating with 70 mJ / cm ² ultraviolet rays using an ultraviolet irradiator (LC6B, H bulb manufactured by Heraeus). When a ceramic slurry was applied to the obtained release film and the release layer surface roughness, peelability, contact angle change after immersion in toluene, pinholes, curls, etc. were evaluated, good evaluation results were obtained. It was.
Methyl ethyl ketone 49.43 parts by mass Toluene 49.43 parts by mass Binder a consisting of a cationic curable substance: 3 ', 4'-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate 0.90 parts by mass
(Product name: Celoxide (registered trademark) 2021P, manufactured by Daicel, solid content of 100% by mass, bifunctional)
Release agent b: Polydimethylsiloxane containing alicyclic epoxy group
0.10 parts by mass (product name, UV Poly215, manufactured by Arakawa Chemical Industries, solid content 100%)
Acid generator: Boron-based cationic curing UV catalyst 0.26 parts by mass (Product name: UV CATA211, active ingredient 19% by mass, manufactured by Arakawa Chemical Industries, Ltd.)

(Example 2)
A release film for producing an ultrathin ceramic green sheet was obtained in the same manner as in Example 1 except that the coating liquid was changed to the coating composition shown below.
Methyl ethyl ketone 49.43 parts by mass Toluene 49.43 parts by mass Binder a comprising a cationic curable substance:
Celoxide (registered trademark) 2021P 0.86 parts by mass
Butanetetracarboxylic acid tetra (3,4-epoxycyclohexylmethyl modified ε-caprolactone 0.04 parts by mass
(Product name: Epolide (registered trademark) GT401, manufactured by Daicel, solid content 100%, tetrafunctional)
Release agent b: UV Poly215 0.10 parts by mass Acid generator: UV CATA211 (active ingredient 19% by mass)
0.26 parts by mass

(Example 3)
A release film for producing an ultrathin ceramic green sheet was obtained in the same manner as in Example 1 except that the coating liquid was changed to the coating composition shown below.
(Coating liquid 3)
Methyl ethyl ketone 49.43 parts by mass Toluene 49.43 parts by mass Binder a comprising a cationic curable substance:
Celoxide (registered trademark) 2021P 0.63 parts by mass
Epolide (registered trademark) GT401 0.27 parts by mass Release agent b: UV Poly215 0.10 parts by mass Acid generator: UV CATA211 (active ingredient 19% by mass)
0.26 parts by mass

(Example 4)
A release film for producing an ultrathin ceramic green sheet was obtained in the same manner as in Example 1 except that the coating liquid was changed to the coating composition shown below.
Methyl ethyl ketone 49.43 parts by mass Toluene 49.43 parts by mass Binder a comprising a cationic curable substance:
Celoxide (registered trademark) 2021P 0.45 parts by mass
Epolide (registered trademark) GT401 0.45 parts by mass Release agent b: UV Poly215 0.10 parts by mass Acid generator: UV CATA211 (active ingredient 19% by mass)
0.26 parts by mass

(Example 5)
A release film for producing an ultrathin ceramic green sheet was obtained in the same manner as in Example 1 except that the coating liquid was changed to the coating composition shown below.
Methyl ethyl ketone 49.43 parts by mass Toluene 49.43 parts by mass Binder a comprising a cationic curable substance:
Celoxide (registered trademark) 2021P 0.86 parts by mass
0.04 part by mass of 2-ethylhexyloxetane
(Product name: Aron Oxetane (registered trademark) OXT-221, manufactured by Toa Gosei Co., Ltd., solid content 100% by mass, bifunctional)
Release agent b: UV Poly215 0.10 parts by mass Acid generator: UV CATA211 (active ingredient 19% by mass)
0.26 parts by mass

(Example 6)
A release film for producing an ultrathin ceramic green sheet was obtained in the same manner as in Example 1 except that the coating liquid was changed to the coating composition shown below.
Methyl ethyl ketone 49.43 parts by mass Toluene 49.43 parts by mass Binder a comprising a cationic curable substance:
Epolide (registered trademark) GT401 0.90 parts by mass Release agent b: UV Poly215 0.10 parts by mass Acid generator: UV CATA211 (active ingredient 19% by mass)
0.26 parts by mass

(Example 7)
A release film for producing an ultrathin ceramic green sheet was obtained in the same manner as in Example 1 except that the coating liquid was changed to the coating composition shown below.
Methyl ethyl ketone 49.43 parts by mass Toluene 49.43 parts by mass Binder a comprising a cationic curable substance:
0.90 parts by mass of polyfunctional alicyclic epoxy group-containing polymer
(Product name: EHPE (registered trademark) 3150, manufactured by Daicel Corporation, solid content 100% by mass, multifunctional)
Release agent b: UV Poly215 0.10 parts by mass Photoacid generator: hexafluoroantimonate triarylsulfonium salt
0.10 parts by mass (product name: CPI (registered trademark) 101A, active ingredient 50% by mass, manufactured by San Apro)

(Example 8)
A release film for producing an ultrathin ceramic green sheet was obtained in the same manner as in Example 1 except that the coating liquid was changed to the coating composition shown below.
Methyl ethyl ketone 49.43 parts by mass Toluene 49.43 parts by mass Binder a comprising a cationic curable substance:
Celoxide (registered trademark) 2021P 0.90 parts by mass Release agent b: UV Poly215 0.10 parts by mass Photoacid generator: hexafluoroantimonate triarylsulfonium salt
0.10 parts by mass (product name: CPI (registered trademark) 101A, active ingredient 50% by mass, manufactured by San Apro)

Example 9
A release film for producing an ultrathin ceramic green sheet was obtained in the same manner as in Example 1 except that the coating liquid was changed to the coating composition shown below.
Methyl ethyl ketone 49.43 parts by mass Toluene 49.43 parts by mass Binder a comprising a cationic curable substance:
Celoxide (registered trademark) 2021P 0.90 parts by mass Release agent b: 0.05 parts by mass of UV Poly215
Polyether-modified polydimethylsiloxane containing acryloyl groups
0.05 parts by mass (Product name: BYK-UV3500, manufactured by Big Chemie Japan, solid content 100%)
Acid generator: UV CATA211 (active ingredient 19% by mass)
0.26 parts by mass

(Example 10)
A release film for producing an ultrathin ceramic green sheet was prepared in the same manner as in Example 1 except that the release agent b of Example 1 was changed to a long-chain alkyl group-containing release agent obtained as follows. Obtained.
(Preparation method of long-chain alkyl group-containing release agent)
Mix in a ratio of 95 mol% stearyl acrylate and 5 mol% hydroxyethyl (meth) acrylate, dilute with toluene to a solids concentration of 40% by mass, and azobisisobutyronitrile under nitrogen flow. Was added at 0.5 mol% for copolymerization to obtain release agent A. The weight average molecular weight of the polymer obtained at this time was 30000.

(Example 11)
A release film for producing an ultrathin ceramic green sheet was obtained in the same manner as in Example 1 except that the coating liquid was changed to the coating composition shown below.
Methyl ethyl ketone 49.43 parts by mass Toluene 49.43 parts by mass Binder a comprising a cationic curable substance:
Celoxide (registered trademark) 2021P 0.90 parts by weight Release agent b: One-end epoxy-modified polydimethylsiloxane
0.10 parts by mass (Product name: X22-173DX, manufactured by Shin-Etsu Chemical Co., Ltd., solid content 100%)
Acid generator: 0.26 parts by mass of UV CATA211

(Example 12)
A release film for producing an ultrathin ceramic green sheet was obtained in the same manner as in Example 1 except that the coating liquid was changed to the coating composition shown below.
Methyl ethyl ketone 49.43 parts by mass Toluene 49.43 parts by mass Binder a comprising a cationic curable substance:
Celoxide (registered trademark) 2021P 0.90 parts by weight Release agent b: Perfluoro-type release agent 0.10 parts by weight Acid generator: UV CATA211 (active ingredient 19% by weight)
0.26 parts by mass

(Example 13)
A release film for producing an ultrathin ceramic green sheet was obtained in the same manner as in Example 1 except that the coating liquid was changed to the coating composition shown below.
Methyl ethyl ketone 49.43 parts by mass Toluene 49.43 parts by mass Binder a comprising a cationic curable substance:
Celoxide (registered trademark) 2021P 0.95 parts by weight Release agent b: UV Poly215 0.05 parts by weight Acid generator: UV CATA211 (active ingredient 19% by weight)
0.26 parts by mass

(Example 14)
A release film for producing an ultrathin ceramic green sheet was obtained in the same manner as in Example 1 except that the coating liquid was changed to the coating composition shown below.
Methyl ethyl ketone 49.43 parts by mass Toluene 49.43 parts by mass Binder a comprising a cationic curable substance:
Celoxide (registered trademark) 2021P 0.80 parts by mass Release agent b: UV Poly215 0.20 parts by mass Acid generator: UV CATA211 (active ingredient 19% by mass)
0.26 parts by mass

(Example 15)
A release film for producing an ultrathin ceramic green sheet was obtained in the same manner as in Example 1 except that the film thickness of Example 1 was changed to the laminated film X2 having a thickness of 25 μm.

(Example 16)
A release film for producing an ultrathin ceramic green sheet was obtained in the same manner as in Example 1 except that coating was performed so that the release layer thickness was 30 nm.

(Example 17)
A release film for producing an ultrathin layer ceramic green sheet was obtained in the same manner as in Example 1 except that coating was performed so that the release layer thickness was 200 nm.

(Example 18)
A release film for producing an ultrathin layer ceramic green sheet was obtained in the same manner as in Example 1 except that coating was performed so that the release layer thickness was 0.8 μm.

(Comparative Example 1)
A release film for producing an ultrathin ceramic green sheet was obtained in the same manner as in Example 1 except that the coating liquid was changed to the coating composition shown below.
Methyl ethyl ketone 49.43 parts by mass Toluene 49.43 parts by mass Binder a comprising a cationic curable substance:
Celoxide (registered trademark) 2021P 1.00 parts by mass Acid generator: UV CATA211 (active ingredient 19% by mass)
0.26 parts by mass

(Comparative Example 2)
A release film for producing an ultrathin layer ceramic sheet was obtained in the same manner as in Example 1 except that the laminated film X1 was changed to a laminated film X3 (E5101-25 μm, manufactured by Toyobo Co., Ltd.). E5101 contained inorganic particles in both the surface layer A and the surface layer B, and the Sa of both the surface layer A and the surface layer B was 24 nm.

(Comparative Example 3)
Mold release for producing ultra-thin ceramic green sheets in the same manner as in Example 1 except that the coating solution was changed to the composition shown below and coating was performed so that the film thickness of the release layer was 0.8 μm. A film was obtained.
Methyl ethyl ketone 44.75 parts by mass Toluene 44.75 parts by mass Binder comprising a photo-radical curable substance:
Dipentaerythritol hexaacrylate
9.90 parts by mass
(Product name: A-DPH, manufactured by Shin-Nakamura Chemical Co., Ltd., solid content 100% by mass)
Release agent b: BYK-UV3500 0.10 parts by mass Photoradical polymerization initiator:
Methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one
0.50 parts by mass (Product name: IRGACURE (registered trademark) 907, manufactured by BASF, 100% by mass of active ingredient)

The release film for producing the ceramic green sheet of the present invention has a very smooth release layer surface and there is no risk of the release layer being eroded by an organic solvent. It is possible to mold a ceramic green sheet that is low and has few defects such as pinholes. Further, by using a cationic curable substance having a small curing shrinkage, it is possible to provide a release film for producing a ceramic green sheet that does not cause a decrease in the accuracy of electrode printing because appearance defects such as curling are suppressed. .

Claims (9)

  A release film in which a release layer is provided on the surface layer A of a polyester film having a surface layer A substantially free of inorganic particles, wherein the release layer contains a cationic curable substance. And a release film for producing a ceramic green sheet obtained by curing a composition containing at least one release agent b. 2. The mold release for producing ceramic green sheets according to claim 1, wherein a difference between the diiodomethane contact angle θ ₁ of the release layer surface and the diiodomethane contact angle θ ₂ of the release layer surface after immersion in toluene is 3.0 ° or less in absolute value. the film.   The release film for producing a ceramic green sheet according to claim 1 or 2, wherein at least one release agent b is a compound containing a silicone skeleton.   The release film for producing a ceramic green sheet according to any one of claims 1 to 3, wherein the binder a containing a cationic curable substance contains 80% by mass or more in the total solid content of the release layer.   The ceramic green according to any one of claims 1 to 4, wherein the binder a containing a cationic curable substance contains at least one compound selected from a compound having an alicyclic epoxy group in its molecule and a compound having an oxetane ring. Release film for sheet manufacturing.   The release film for producing a ceramic green sheet according to any one of claims 1 to 5, wherein at least one of the release agents b is a silicone containing an alicyclic epoxy group.   The mold release for producing ceramic green sheets according to any one of claims 1 to 6, wherein the average surface roughness (Sa) of the release layer surface is 7 nm or less and the maximum protrusion height (P) is 100 nm or less. the film.   It is a manufacturing method of the ceramic green sheet which has thickness of 0.2 micrometer-1.0 micrometer, Comprising: The manufacturing method of the ceramic green sheet using the release film for ceramic green sheet manufacture in any one of Claims 1-7. The manufacturing method of the ceramic capacitor which employ | adopts the manufacturing method of the ceramic green sheet of Claim 8.