JP6841355B2 - Release film for manufacturing ceramic green sheets - Google Patents

Description

The present invention relates to a release film for manufacturing a ceramic green sheet. More specifically, the present invention relates to a release film for manufacturing a ceramic green sheet, which can achieve both good take-up property and prevention of pinholes and partial thickness variations even when the ceramic green sheet is thinned.

Conventionally, the release film for ceramic green sheet production is stored in a wound state by making the surface roughness of the surface (back surface) opposite to the surface on which the release agent layer of the base film is provided relatively rough. A technique has been disclosed for eliminating problems such as the front and back surfaces of a release film for producing a ceramic green sheet sticking (blocking) when the film is used (see, for example, Patent Document 1). However, such a conventional technique has a problem that pinholes and partial thickness variations occur because the protrusions are large.

Therefore, a technique has been disclosed that attempts to prevent pinholes and partial thickness variations from occurring in the ceramic green sheet by filling the protrusions on the back surface with a coating layer in order to reduce the height of the protrusions (for example). , Patent Document 2). However, according to the conventional technique, although the protrusion height is low, the protrusion density is low, so that the pressure applied to the protrusions is large, and when the ceramic green sheet is further thinned, pinholes are generated. there were.

Japanese Unexamined Patent Publication No. 2003-203822 Japanese Unexamined Patent Publication No. 2014-144636

The present invention has been made against the background of the problems of the prior art. That is, an object of the present invention is for producing an excellent ceramic green sheet capable of achieving both good winding performance and prevention of pinholes and partial thickness variations even when the ceramic green sheet is thinned. The purpose is to provide a release film.

The present inventor has completed the present invention as a result of diligent studies to achieve such an object. That is, the present invention has the following configuration.
1. 1. The base material is a polyester film containing substantially no particles, and the polyester film is a polyester film containing at least one selected from polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. It has a release coating layer on one surface and an easy-slip coating layer containing particles on the other surface, and the average length (RSm) of the roughness curve elements of the easy-slip coating layer. A release film for producing a ceramic green sheet, characterized in that the thickness is 10 μm or less.
2. 2. The release for manufacturing a ceramic green sheet according to the first aspect, wherein the region surface average roughness (Sa) of the slippery coating layer is 1 nm or more and 25 nm or less, and the maximum protrusion height (P) is 60 nm or more and 500 nm or less. Mold film.
3. 3. The release for producing a ceramic green sheet according to the first or second above, wherein the region surface average roughness (Sa) of the release coating layer is 5 nm or less, and the maximum protrusion height (P) is 30 nm or less. Mold film.
4. The release film for producing a ceramic green sheet according to any one of the above 1 to 3, wherein the thickness of the easy-slip coating layer is 0.001 μm or more and 2 μm or less.
5. A method for producing a ceramic green sheet, which comprises using the release film for producing a ceramic green sheet according to any one of the first to fourth aspects.
6. The method for producing a ceramic green sheet according to the fifth aspect above, wherein the thickness of the ceramic green sheet to be produced is 0.2 μm or more and 2 μm or less.
7. A method for manufacturing a ceramic capacitor, which comprises adopting the method for manufacturing a ceramic green sheet according to the fifth or sixth method.

According to the present invention, there is provided a release film for manufacturing a ceramic green sheet that can achieve both good take-up property and prevention of pinholes and partial thickness variations even when the ceramic green sheet is thinned. Is possible.

Hereinafter, the present invention will be described in detail.
The release film for producing a ceramic green sheet of the present invention (hereinafter, may be simply referred to as a release film) has a release coating layer on one side and particles on the other side of a biaxially oriented polyester film which is a base film. It is a release film having an easy-to-slip coating layer including.

(Base film)
The film preferably used as a base material in the present invention is a film composed of a polyester resin, and a polyester film containing at least one selected from polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate is mainly used. preferable. Further, a film made of polyester in which a third component monomer is copolymerized as a part of the dicarboxylic acid component or the diol component of the polyester as described above may be used. Among these polyester films, polyethylene terephthalate film is most preferable from the viewpoint of the balance between physical properties and cost.

Further, the polyester film may be a single layer or a plurality of layers. Further, as long as the effects of the present invention are exhibited, each of these layers can contain various additives in the polyester resin, if necessary. Examples of the additive include antioxidants, lightfasteners, antigelling agents, organic wetting agents, antistatic agents, ultraviolet absorbers and the like.

(Easy slip coating layer)
The release film of the present invention has an easy-slip coating layer on one surface of the polyester base film as described above. It is preferable that the slippery coating layer contains at least a binder resin and particles.

(Binder resin in the easy-slip coating layer)
The binder resin constituting the slippery coating layer is not particularly limited, but specific examples of the polymer include polyester resin, acrylic resin, urethane resin, polyvinyl resin (polyvinyl alcohol, etc.), polyalkylene glycol, polyalkyleneimine, and methyl cellulose. , Hydroxycellulose, polymers and the like. Among these, polyester resin, acrylic resin, and urethane resin are preferably used from the viewpoint of particle retention and adhesion. Further, a polyester resin is particularly preferable in consideration of compatibility with a polyester film. The polyester of the binder is preferably a copolymerized polyester in order to achieve solubility in a solvent, dispersibility, and adhesion to a base film and other layers. The polyester resin may be modified with polyurethane. Further, as another preferable binder resin constituting the I Ching coating layer on the polyester base film, urethane resin can be mentioned. Examples of the urethane resin include polycarbonate polyurethane resin. Further, the polyester resin and the polyurethane resin may be used in combination, or the other binder resin described above may be used in combination.

(Crosslinking agent)
In the present invention, in order to form a crosslinked structure in the easy-slip coating layer, the easy-slip coating layer may be formed by containing a cross-linking agent. By containing a cross-linking agent, it becomes possible to further improve the adhesion under high temperature and high humidity. Specific examples of the cross-linking agent include urea-based, epoxy-based, melamine-based, isocyanate-based, oxazoline-based, and carbodiimide-based. Further, in order to promote the cross-linking reaction, a catalyst or the like can be appropriately used as needed.

(Particles in the easy-to-slip coating layer)
The slippery coating layer preferably contains lubricant particles in order to impart slipperiness to the surface. The particles may be inorganic particles or organic particles, and are not particularly limited. (1) Silica, kaolinite, talc, light calcium carbonate, heavy calcium carbonate, zeolite, alumina, etc. Barium Sulfate, Carbon Black, Zinc Oxide, Zinc Sulfate, Zinc Carbonate, Zinc Oxide, Titanium Dioxide, Satin White, Aluminum Silate, Kaiso Soil, Calcium Sirate, Aluminum Hydroxide, Hydrate Halloysite, Calcium Carbonate, Magnesium Carbonate, Calcium Phosphate, Hydroxide Inorganic particles such as magnesium and barium sulfate, (2) acrylic or methacrylic, vinyl chloride, vinyl acetate, nylon, styrene / acrylic, styrene / butadiene, polystyrene / acrylic, polystyrene / isoprene, polystyrene / Organic particles such as isoprene-based, methyl methacrylate / butyl methacrylate-based, melamine-based, polycarbonate-based, urea-based, epoxy-based, urethane-based, phenol-based, diallyl phthalate-based, and polyester-based are examples, but are suitable for the coating layer. Silica is particularly preferably used to provide slipperiness.

The average particle size of the particles is preferably 10 nm or more, more preferably 20 nm or more, still more preferably 30 nm or more. It is preferable that the average particle size of the particles is 10 nm or more because it is difficult to aggregate and slipperiness can be ensured.

The average particle size of the particles is preferably 1000 nm or less, more preferably 800 nm or less, still more preferably 600 nm or less. When the average particle size of the particles is 1000 nm or less, transparency is maintained and the particles do not fall off, which is preferable.

Further, for example, it is also possible to mix small particles having an average particle size of about 10 to 200 nm and large particles having an average particle size of about 300 to 1000 nm, which will be described later in terms of region surface average roughness (Sa) and maximum protrusion height (Sa). It is preferable to reduce the average length (RSm) of the roughness curve element while keeping P) small to achieve both slipperiness and smoothness, and particularly preferably, small particles of 30 nm or more and 150 nm or less and average particles. Large particles having a diameter of 350 to 600 nm are used in combination. When small particles and large particles are mixed, it is preferable that the mass content of the small particles is larger than the mass content of the large particles with respect to the total solid content of the coating layer.

The average particle size of the particles is measured by observing the particles in the cross section of the processed film with a transmission electron microscope or a scanning electron microscope, observing 100 non-aggregated particles, and using the average value as the average particle size. The method was to use the diameter.

The shape of the particles is not particularly limited as long as it satisfies the object of the present invention, and spherical particles and amorphous non-spherical particles can be used. The particle size of the amorphous particles can be calculated as the equivalent circle diameter. The equivalent circle diameter is a value obtained by dividing the observed particle area by π, calculating the square root, and doubling it.

The ratio of the particles to the total solid content of the slippery coating layer is preferably 50% by mass or less, more preferably 40% by mass or less, and further preferably 30% by mass or less. When the ratio of the particles to the total solid content of the easy-slip coating layer is 50% by mass or less, the transparency is maintained and the particles do not significantly fall off from the easy-slip coating layer, which is preferable.

The ratio of the particles to the total solid content of the slippery coating layer is preferably 1% by mass or more, more preferably 1.5% by mass or more, and further preferably 2% by mass or more. When the ratio of the particles to the total solid content of the easy-slip coating layer is 1% by mass or more, slipperiness can be ensured, which is preferable.

As a method for measuring the content of particles contained in the easy-slip coating layer, for example, when the easy-slip coating layer contains an organic component resin and inorganic particles, the following method can be used. First, the easy-slip coating layer provided on the processed film is extracted from the processed film using a solvent or the like and dried to dryness to take out the easy-slip coating layer. Next, heat is applied to the obtained easy-slip coating layer, and the organic component contained in the easy-slip coating layer is burned and distilled off by heat, whereby only the inorganic component can be obtained. By measuring the weights of the obtained inorganic component and the easy-slip coating layer before combustion distillation, the mass% of the particles contained in the easy-slip coating layer can be measured. At this time, accurate measurement can be performed by using a commercially available differential thermal / thermogravimetric simultaneous measuring device.

(Additives in the easy-to-slip coating layer)
In order to impart other functionality to the slippery coating layer, various additives may be contained within a range that does not impair the coating appearance. Examples of the additive include fluorescent dyes, fluorescent whitening agents, plasticizing agents, ultraviolet absorbers, pigment dispersants, defoaming agents, defoaming agents, preservatives and the like.

The easy-slip coating layer may contain a surfactant for the purpose of improving the leveling property at the time of coating and defoaming the coating liquid. The surfactant may be any of a cationic type, an anion type, nonionic type and the like, but a silicone type, acetylene glycol type or fluorine type surfactant is preferable. It is preferable that these surfactants are contained in the coating layer within a range that does not cause an abnormality in the coating appearance when added excessively.

As the coating method, either a so-called in-line coating method in which the polyester base film is applied at the same time as the film is formed and a so-called offline coating method in which the polyester base film is separately applied with a coater after the film is formed can be applied. Is more efficient and more preferable.

As a coating method, any known method can be used as a method for coating the coating liquid on a polyethylene terephthalate (hereinafter, may be abbreviated as PET) film. For example, reverse roll coating method, gravure coating method, kiss coating method, die coater method, roll brushing method, spray coating method, air knife coating method, wire bar coating method, pipe doctor method, impregnation coating method, curtain coating method, etc. Can be mentioned. These methods are applied alone or in combination.

In the present invention, as a method of providing the easy-slip coating layer on the polyester film, a method of applying a coating liquid containing a solvent, particles and a resin to the polyester film and drying it can be mentioned. Examples of the solvent include an organic solvent such as toluene, water, or a mixed system of water and a water-soluble organic solvent. However, from the viewpoint of environmental problems, water alone or a so-called aqueous system obtained by mixing a water-soluble organic solvent with water is preferable. Solvent is preferred.

The solid content concentration of the slippery coating liquid depends on the type of binder resin, the type of solvent, and the like, but is preferably 0.5% by mass or more, and more preferably 1% by mass or more. The solid content concentration of the coating liquid is preferably 35% by mass or less, more preferably 20% by mass or less.

The drying temperature after coating also depends on the type of binder resin, the type of solvent, the presence or absence of a cross-linking agent, the solid content concentration, and the like, but is preferably 70 ° C. or higher, and preferably 250 ° C. or lower.

(Manufacturing of polyester film)
In the present invention, the polyester film to be the base film can be produced according to a general method for producing a polyester film. For example, a non-oriented polyester obtained by melting a polyester resin and extruding it into a sheet is stretched in the vertical direction by utilizing the speed difference of rolls at a temperature equal to or higher than the glass transition temperature, and then stretched in the horizontal direction by a tenter. A method of applying heat treatment can be mentioned. Further, there is also a method of biaxially stretching in the tenter at the same time in the vertical and horizontal directions.

In the present invention, the polyester film to be the base film may be a uniaxially stretched film or a biaxially stretched film, but is preferably a biaxially stretched film.

The thickness of the polyester film base material is preferably 5 μm or more, more preferably 10 μm or more, and further preferably 15 μm or more. When the thickness is 5 μm or more, wrinkles are less likely to occur during film transportation, which is preferable.

The thickness of the polyester film base material is preferably 50 μm or less, more preferably 45 μm or less, and further preferably 40 μm or less. When the thickness is 40 μm or less, the cost per unit area is reduced, which is preferable.

In the case of in-line coating, it may be applied to an unstretched film before stretching in the vertical direction, or may be applied to a uniaxially stretched film after stretching in the vertical direction and before stretching in the horizontal direction. When coating is applied before stretching in the longitudinal direction, it is preferable to provide a drying step before stretching the roll. When coating on a uniaxially stretched film before stretching in the lateral direction, the drying step can also be combined with the film heating step in the tenter, so it is not always necessary to provide a separate drying step. The same applies to the case of simultaneous biaxial stretching.

The film thickness of the slippery coating layer is preferably 0.001 μm or more, more preferably 0.01 μm or more, still more preferably 0.02 μm or more, and particularly preferably 0.03 μm or more. When the thickness of the coating layer is 0.001 μm or more, the film-forming property of the coating film is maintained and a uniform coating film can be obtained, which is preferable.

The film thickness of the slippery coating layer is preferably 2 μm or less, more preferably 1 μm or less, further preferably 0.8 μm or less, and particularly preferably 0.5 μm or less. When the film thickness of the coating layer is 2 μm or less, blocking may not occur, which is preferable.

The ceramic green sheet, which is coated and molded on the release coating layer described later, is wound into a roll together with the release film after coating and molding. At this time, the easy-slip coating layer of the release film is wound in contact with the surface of the ceramic green sheet. In order not to generate defects on the surface of the ceramic green sheet, the outer surface of the easy-slip coating layer (the surface of the easy-slip coating layer of the entire coating film that is not in contact with the polyester film) needs to be moderately flat, and the region. It is preferable that the surface average roughness (Sa) is 1 nm or more and 25 nm or less and the maximum protrusion height (P) is 60 nm or more and 500 nm or less.

If the region surface average roughness (Sa) of the outer surface of the easy-slip coating layer is 1 nm or more and the maximum protrusion height (P) is 60 nm or more, the easy-slip coating surface does not become too smooth and appropriate slipperiness is maintained. It is preferable because it can be done. When the region surface average roughness (Sa) is 25 nm or less and the maximum protrusion height (P) is 500 nm or less, the easy-slip coated surface is not too rough and defects of the ceramic green sheet due to protrusions do not occur, which is preferable.

In the present invention, in addition to setting the region surface average roughness (Sa) and the maximum protrusion height (P) within the above ranges, the average length (RSm) of the roughness curve elements is preferably 10 μm or less. By controlling the average length (RSm) of the roughness curve elements to 10 μm or less, the number of protrusions per unit area increases. When the number of protrusions increases, the pressure applied to each protrusion is dispersed and becomes smaller, which is preferable because the occurrence of pinholes can be effectively suppressed. The average length (RSm) of the roughness curve element is more preferably 5 μm or less, still more preferably 3 μm or less. However, if the average length (RSm) of the roughness curve element is too small, it is related to the content of particles in the easy-to-slip coating layer being too large, and the region surface average roughness (Sa) becomes large. Since it is also related to the increase in the maximum protrusion height (P), it is preferably 0.1 μm or more, and may be 0.5 μm or more, or 1 μm or more.

In the present invention, in order to keep the average length (RSm) of the roughness curve element within a predetermined range, the average particle size of the particles contained in the slippery coating layer is preferably 1000 nm or less. It is more preferably 800 nm or less, still more preferably 600 nm or less. When the particle diameter is 1000 nm or less, the distance between the particles does not become too large, and RSm is preferably adjusted to a predetermined range.

(Release coating layer)
The resin constituting the release coating layer in the present invention is not particularly limited, and silicone resin, fluororesin, alkyd resin, various waxes, aliphatic olefins and the like can be used, and each resin may be used alone or in combination of two or more. You can also do it.

As the release coating layer of the present invention, for example, the silicone resin is a resin having a silicone structure in the molecule, and examples thereof include curable silicone, silicone graft resin, and modified silicone resin such as alkyl-modified. From the viewpoint of properties and the like, it is preferable to use a reactive cured silicone resin. As the reactive cured silicone resin, an addition reaction type resin, a condensation reaction type resin, an ultraviolet ray or electron beam curing type resin, and the like can be used. More preferably, a low-temperature curable addition reaction system that can be processed at a low temperature, and an ultraviolet or electron beam-curable system are preferable. By using these, it is possible to process at a low temperature when coating the polyester film. Therefore, there is little heat damage to the polyester film during processing, a polyester film with high flatness can be obtained, and defects such as pinholes can be reduced even when manufacturing an ultra-thin ceramic green sheet having a thickness of 0.2 to 2 μm. ..

Examples of the addition reaction type silicone resin include those in which polydimethylsiloxane having a vinyl group introduced at the terminal or side chain and hydrodienesiloxane are reacted with each other using a platinum catalyst to be cured. At this time, it is more preferable to use a resin that can be cured at 120 ° C. within 30 seconds because it can be processed at a low temperature. Examples include low temperature add-curing types manufactured by Toray Dow Corning (LCC1006L, LTC1056L, LTC300B, LTC303E, LTC310, LTC314, LTC350G, LTC450A, LTC371G, LTC750A, LTC245, LTC245A, LTC245A, LTC245A, etc.) -510, BY24-561, BY24-562, etc.), Shin-Etsu Chemical's solvent-added + UV curable type (X62-5040, X62-5065, X62-5072T, KS5508, etc.), Dual cure curable type (X62-2835, X62, etc.) -2834, X62-1980, etc.) and the like.

As the silicone resin of the condensation reaction system, for example, a polydimethylsiloxane having an OH group at the terminal and a polydimethylsiloxane having an H group at the terminal are subjected to a condensation reaction using an organic tin catalyst to form a three-dimensional crosslinked structure. Can be mentioned.

As the most basic type of UV-curable silicone resin, for example, one that uses the same radical reaction as normal silicone rubber cross-linking, one that introduces an unsaturated group and photo-cures, and one that decomposes onium salts with UV light. Examples thereof include those in which a strong acid is generated and the epoxy group is cleaved and crosslinked by this, and those in which the epoxy group is crosslinked by an addition reaction of thiol to vinylsiloxane. Further, an electron beam can be used instead of the ultraviolet ray. The electron beam has stronger energy than ultraviolet rays, and it is possible to carry out a radical cross-linking reaction without using an initiator as in the case of ultraviolet curing. Examples of resins used include UV curable silicones manufactured by Shin-Etsu Chemical Co., Ltd. (X62-7028A / B, X62-7052, X62-7205, X62-7622, X62-7629, X62-7660, etc.), Momentary Performance. UV curable silicones manufactured by Materials (TPR6502, TPR6501, TPR6500, UV9300, UV9315, XS56-A2982, UV9430, etc.), UV curable silicones manufactured by Arakawa Chemical (Silicollies UV POLY200, POLY215, POLY201, KF-UV265AM, etc.) ).

As the ultraviolet curable silicone resin, acrylate-modified or glycidoxy-modified polydimethylsiloxane can also be used. Good mold release performance can also be obtained by mixing these modified polydimethylsiloxanes with a polyfunctional acrylate resin, epoxy resin, or the like and using them in the presence of an initiator.

As examples of other resins used, alkyd resins and acrylic resins that have been stearyl-modified or lauryl-modified, or alkyd-based resins and acrylic-based resins obtained by the reaction of methylated melamine are also suitable.

Examples of the aminoalkyd resin obtained by the above-mentioned reaction of methylated melamine include Tessfine 303, Tessfine 305, and Tessfine 314 manufactured by Hitachi Kasei Co., Ltd. Examples of the amino acrylic resin obtained by the reaction of methylated melamine include Tessfine 322 manufactured by Hitachi Kasei Co., Ltd.

When the above resin is used for the release coating layer of the present invention, one type may be used, or two or more types may be mixed and used. It is also possible to mix additives such as a light peeling additive and a heavy peeling additive in order to adjust the peeling force.

The release coating layer of 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 that the release coating layer does not substantially contain particles or the like that form protrusions.

Additives such as an adhesion improver and an antistatic agent may be added to the release coating layer of the present invention. Further, in order to improve the adhesion to the base material, it is also preferable to perform pretreatment such as anchor coating, corona treatment, plasma treatment, atmospheric pressure plasma treatment, etc. on the surface of the polyester film before providing the release coating layer.

In the present invention, the thickness of the release coating layer may be set according to the purpose of use and is not particularly limited, but preferably, the thickness of the release coating layer after curing is in the range of 0.005 to 2 μm. Good. When the thickness of the release coating layer is 0.005 μm or more, the peeling performance is maintained, which is preferable. Further, when the thickness of the release coating layer is 2 μm or less, the curing time does not become too long, and there is no possibility of uneven thickness of the ceramic green sheet due to the deterioration of the flatness of the release film, which is preferable. Further, since the curing time does not become too long, there is no possibility that the resin constituting the release coating layer will aggregate and there is no possibility of forming protrusions, so that pinhole defects of the ceramic green sheet are less likely to occur, which is preferable.

The outer surface of the film on which the release coating layer is formed (the surface of the release coating layer of the entire coating film that is not in contact with the polyester film) is flat so as not to cause defects in the ceramic green sheet coated and molded on it. It is preferable that the region surface average roughness (Sa) is 5 nm or less and the maximum protrusion height (P) is 30 nm or less. Further, it is more preferable that the region surface average roughness (Sa) is 5 nm or less and the maximum protrusion height (P) is 20 nm or less. Particularly preferably, the region surface average roughness (Sa) is 3 nm or less, and the maximum protrusion height (P) is 17 nm or less. When the region surface roughness (Sa) is 5 nm or less and the maximum protrusion height (P) is 30 nm or less, defects such as pinholes do not occur when the ceramic green sheet is formed, and the yield is good, which is preferable. It can be said that the smaller the region surface average roughness (Sa) is, the more preferable it is, but it may be 0.1 nm or more, or 0.3 nm or more. It can be said that the smaller the maximum protrusion height (P) is, the more preferable it is, but it may be 1 nm or more, or 3 nm or more.

In the present invention, in order to adjust the surface of the film on which the release coating layer is formed to a predetermined roughness range, it is preferable that the PET film contains substantially no particles. The term "substantially free of particles" as used in the present invention means that for both the base film and the release coating layer, for example, in the case of inorganic particles, the elements derived from the particles are quantitatively analyzed by fluorescent X-ray analysis. When it is used, it is defined as 50 ppm or less, preferably 10 ppm or less, and most preferably the detection limit or less. This means that even if particles are not actively added to the base film, contamination components derived from foreign substances and stains attached to the raw material resin or the line or device in the manufacturing process of the film are peeled off and mixed in the film. This is because it may be done.

In the present invention, the method for forming the release coating layer is not particularly limited, and a coating liquid in which a releaseable resin is dissolved or dispersed is developed by coating on one surface of a polyester film of a base material, and a solvent is used. After removing the above by drying, a method of heat drying, thermosetting or ultraviolet curing is used. At this time, the drying temperature during solvent drying and thermosetting is preferably 180 ° C. or lower, more preferably 150 ° C. or lower, and most preferably 120 ° C. or lower. The heating time is preferably 30 seconds or less, more preferably 20 seconds or less. When the temperature is 180 ° C. or lower, the flatness of the film is maintained and the possibility of causing uneven thickness of the ceramic green sheet is small, which is preferable. When the temperature is 120 ° C. or lower, 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.

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

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

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

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

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

Next, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is naturally not limited to the following Examples. The evaluation method used in the present invention is as follows.

(1) Surface characteristics of coated film Values measured under the following conditions using a non-contact surface shape measurement system (VertScan R550H-M100). For the region surface average roughness (Sa) and the average length (RSm) of the roughness curve elements, the average value of 5 measurements was adopted, and for the maximum protrusion height (P), the maximum value of 5 measurements was adopted.
(Measurement condition)
-Measurement mode: WAVE mode-Objective lens: 50x-0.5 x Tube lens-Measurement area 187 x 139 μm (Sa, P measurement)
-Measurement length (Lr: reference length): 187 μm (RSm measurement)

(2) Evaluation of pinholes and thickness variation of ceramic green sheet The composition consisting of the following materials is stirred and mixed, and dispersed for 2 hours using a paint shaker using 2.0 mm glass beads as a dispersion medium to obtain a ceramic slurry. It was.
Toluene 22.5% by mass
Ethanol 22.5% by mass
Barium titanate (HPBT-1 manufactured by Fuji Titanium Industry Co., Ltd.) 50% by mass
Polyvinyl butyral (Eslek BH-3 manufactured by Sekisui Chemical Co., Ltd.)
5 mass%
Next, the release surface of the release film sample was coated with an applicator so that the dried slurry had a thickness of 0.5 μm, dried at 90 ° C. for 1 minute, and then the slurry surface and the smoothing coating layer surface were overlapped with each other. After applying a load of 1 kg / cm ² for 1 minute, 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, shine light from the opposite surface of the coated surface of the ceramic slurry within a range ^{of 25 cm 2, observe the occurrence of pinholes through which light appears, and use the following criteria.} It was judged visually.
◯: No pinholes, thickness variation No particular problem ×: Pinholes are slightly generated and / or thickness variation is slightly noticeable ××: Pinholes are slightly generated and thickness variation Slightly noticeable XXX: There are many pinholes, and the thickness variation is large and noticeable.

(Preparation of polyethylene terephthalate pellets (PET (I)))
As the esterification reaction device, a continuous esterification reaction device consisting of a stirrer, a splitter, a raw material charging port, and a three-stage complete mixing tank having a raw material charging port and a product outlet was used. TPA (terephthalic acid) was set to 2 tons / hour, EG (ethylene glycol) was set to 2 mol per 1 mol of TPA, antimony trioxide was set to an amount of 160 ppm of Sb atoms with respect to the PET produced, and these slurries were esterified. It was continuously supplied to the first esterification reaction can of the chemical reaction apparatus and reacted at normal pressure for an average residence time of 4 hours and 255 ° C. Next, the reaction products in the first esterification reaction can are continuously taken out of the system and supplied to the second esterification reaction can, and distilled off from the first esterification reaction can in the second esterification reaction can. EG is supplied in an amount of 8% by mass with respect to the produced PET, and an EG solution containing an amount of magnesium tetrahydrate having an amount of Mg atoms of 65 ppm with respect to the produced PET and 40 ppm of P atoms with respect to the produced PET. An EG solution containing an amount of TMPA (trimethyl phosphate) was added, and the reaction was carried out at normal pressure for an average residence time of 1 hour and 260 ° C. Next, the reaction product of the second esterification reaction can is continuously taken out of the system and supplied to the third esterification reaction can, and 39 MPa (400 kg / cm ² ) using a high-pressure disperser (manufactured by Nippon Seiki Co., Ltd.). 0.2% by mass of porous colloidal silica having an average particle size of 0.9 μm and 1% by mass of ammonium salt of polyacrylic acid attached per calcium carbonate after dispersion treatment with an average number of treatments of 5 passes under the pressure of 0.4% by mass of synthetic calcium carbonate having a diameter of 0.6 μm was added as an EG slurry of 10% each, and the reaction was carried out at normal pressure for an average residence time of 0.5 hours and at 260 ° C. The esterification reaction product produced in the third esterification reaction can was continuously supplied to a three-stage continuous polycondensation reaction apparatus to carry out polycondensation, and a stainless steel fiber having a 95% cut diameter of 20 μm was sintered. After filtering with a filter, ultrafiltration was performed, extruded into water, cooled, and then 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 having an intrinsic viscosity of 0.62 dl / g containing no particles such as calcium carbonate and silica was obtained (hereinafter, abbreviated as PET (II)).

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

(Polyester resin A-1 polymerization)
In a stainless steel autoclave equipped with a stirrer, thermometer, and partial reflux cooler, 194.2 parts by mass of dimethyl terephthalate, 184.5 parts by mass of dimethyl isophthalate, 14.8 parts by mass of dimethyl 5-sodium sulfoisophthalate, 185.1 parts by mass of ethylene glycol, 185.1 parts by mass of neopentyl glycol, and 0.2 parts by mass of tetra-n-butyl titanate were charged, and a transesterification reaction was carried out at a temperature of 160 ° C. to 220 ° C. for 4 hours. .. Then, the temperature was raised to 255 ° C., the reaction system was gradually depressurized, and then the reaction was carried out under a reduced pressure of 30 Pa for 1 hour and 30 minutes to obtain a copolymerized polyester resin (A-1). The obtained copolymerized polyester resin (A-1) was pale yellow and transparent. The reduced viscosity of the copolymerized polyester resin (A-1) was measured and found to be 0.60 dl / g. The glass transition temperature by DSC was 65 ° C.

(Manufacture of polyester aqueous dispersion Aw-1)
30 parts by mass of polyester resin (A-1) and 15 parts by mass of ethylene glycol-n-butyl ether were placed in a reactor equipped with a stirrer, a thermometer and a reflux device, and heated and stirred at 110 ° C. to dissolve the resin. After the resin was completely dissolved, 55 parts by mass of water was gradually added to the polyester solution with stirring. After the addition, the liquid was cooled to room temperature with stirring to prepare a milky white polyester aqueous dispersion (Aw-1) having a solid content of 30% by mass.

(Polyester resin A-2 polymerization)
In a stainless steel autoclave equipped with a stirrer, thermometer, and partial reflux condenser, 163 parts by mass of dimethyl terephthalate, 163 parts by mass of dimethyl isophthalate, 169 parts by mass of 1,4 butanediol, 324 parts by mass of ethylene glycol, and 0.5 parts by mass of tetra-n-butyl titanate was charged, and a transesterification reaction was carried out from 160 ° C. to 220 ° C. over 4 hours.
Next, 14 parts by mass of fumaric acid and 203 parts by mass of sebacic acid were added, and the temperature was raised from 200 ° C. to 220 ° C. over 1 hour to carry out an esterification reaction. Then, the temperature was raised to 255 ° C., the reaction system was gradually depressurized, and then the reaction was carried out under a reduced pressure of 29 Pa for 1 hour and 30 minutes to obtain a hydrophobic copolymerized polyester resin (A-2). The obtained hydrophobic copolymerized polyester resin (A-2) was pale yellow and transparent.

(Manufacture of polyester aqueous dispersion Aw-2)
Next, 60 parts by mass of the copolymerized polyester resin (A-2), 45 parts by mass of methyl ethyl ketone and 15 parts by mass of isopropyl alcohol were added to a reactor equipped with a stirrer for producing graft resin, a thermometer, a reflux device and a quantitative dropping device. The resin was dissolved by heating and stirring at 65 ° C. After the resin was completely dissolved, 24 parts by mass of maleic anhydride was added to the polyester solution.
Then, a solution prepared by dissolving 16 parts by mass of styrene and 1.5 parts by mass of azobisdimethylvaleronitrile in 19 parts by mass of methyl ethyl ketone was added dropwise to the polyester solution at 0.1 ml / min, and stirring was continued for another 2 hours. After sampling for analysis from the reaction solution, 8 parts by mass of methanol was added. Then, 300 parts by mass of water and 24 parts by mass of triethylamine were added to the reaction solution, and the mixture was stirred for 1 hour.
Then, the internal temperature of the reactor was raised to 100 ° C., methyl ethyl ketone, isopropyl alcohol, and excess triethylamine were distilled off by distillation to obtain a pale yellow transparent polyester resin, and uniform water dispersibility with a solid content concentration of 25% by mass. A polyester-based graft copolymer dispersion (Aw-2) was prepared. The glass transition temperature of the obtained polyester-based graft copolymer was 68 ° C.

(Manufacture of polyurethane aqueous dispersion Aw-3)
In a four-necked flask equipped with a stirrer, Dimroth condenser, nitrogen introduction tube, silica gel drying tube, and thermometer, 43.75 parts by mass of 4,4-dicyclohexylmethanediiscetone, 12.85 parts by mass of dimethylolbutanoic acid, 153.41 parts by mass of polyhexamethylene carbonate diol having a number average molecular weight of 2000, 0.03 parts by mass of dibutyltin dilaurate, and 84.00 parts by mass of acetone as a solvent were added, and the mixture was stirred at 75 ° C. for 3 hours under a nitrogen atmosphere for reaction. It was confirmed that the liquid reached a predetermined amine equivalent. Next, the reaction solution was cooled to 40 ° C., and then 8.77 parts by mass of triethylamine was added to obtain a polyurethane prepolymer solution. Next, 450 g of water was added to a reaction vessel equipped with a homodisper capable of high-speed stirring, the temperature was adjusted to 25 ° C., and the polyurethane prepolymer solution was added and dispersed in water while stirring and mixing at ^{2000 min-1.} .. Then, under reduced pressure, acetone and a part of water were removed to prepare a water-soluble polyurethane resin solution Aw-3 having a solid content of 37% by mass. The glass transition temperature of the obtained polyurethane resin was −30 ° C.

(Silica particle B-1)
Colloidal silica (manufactured by Nissan Chemical Industries, Ltd., trade name Snowtex OL, average particle size 40 nm, solid content concentration 20% by mass)

(Silica Particle B-2)
Colloidal silica (manufactured by Nissan Chemical Industries, Ltd., trade name Snowtex ZL, average particle size 100 nm, solid content concentration 40% by mass)

(Silica Particle B-3)
Colloidal silica (manufactured by Nissan Chemical Industries, Ltd., trade name MP2040, average particle size 200 nm, solid content concentration 40% by mass)

(Silica particles B-4)
Colloidal silica (manufactured by Nissan Chemical Industries, Ltd., trade name MP4540M, average particle size 450 nm, solid content concentration 40% by mass)

(Acrylic particles B-5)
Acrylic particle aqueous dispersion (manufactured by Nippon Shokubai, trade name MX100W, average particle size 150 nm, solid content concentration 10% by mass)

(Release agent solution X-1)
100 parts by mass of UV curable silicone resin (UV9300 manufactured by Momentive, solid content concentration 100% by mass) and 1 part by mass of curing catalyst bis (alkylphenyl) iodonium hexafluoroantimonate, toluene / methyl ethyl ketone / heptane (= 3: 5:) 2) Dilute with a solution to prepare a release agent solution having a solid content of 2% by mass.

(Release agent solution X-2)
Thermo-curable aminoalkyd resin (Tessfine 314 manufactured by Hitachi Kasei Co., Ltd., solid content 60% by mass) and p-toluenesulfonic acid (Hitachi Kasei Co., Ltd., dryer 900, solid content 50% by mass) as a curing catalyst 1. 2 parts by mass was diluted with a toluene / methyl ethyl ketone / heptane (= 3: 5: 2) solution to prepare a release agent solution having a solid content of 2% by mass.

(Back surface smoothing coating liquid Y)
Polydimethylsiloxane having 94 parts by mass of dipentaerythritol hexaacrylate [solid content 100% by mass] as an active energy ray compound and a polyether-modified acryloyl group as a polyorganosiloxane [manufactured by Big Chemie Japan Co., Ltd., trade name "BYK-3500", solid content 100% by mass] 1 part by mass and α-aminoalkylphenone-based photopolymerization initiator as a photopolymerization initiator [BASF, trade name "IRGACURE907", 2-methyl-1 [4- (Methylthio) phenyl] -2-morpholinopropane-1-one, solid content 100% by mass] 5 parts by mass is diluted with an isopropyl alcohol / methyl ethyl ketone mixed solvent (mass ratio 3/1) to obtain a solid content. A material for forming a back surface smoothing coat layer of 20% by mass was obtained.

(Example 1)
(Adjustment of easy slip coating liquid 1)
The I Ching coating liquid 1 having the following composition was adjusted.
(Easy slip coating liquid 1)
Water 48.33 parts by mass Isopropyl alcohol 35.00 parts by mass Polyester aqueous dispersion Aw-1 15.78 parts by mass (solid content concentration 30% by mass)
Silica particles B-3 0.59 parts by mass (average particle size 200 nm, solid content concentration 40% by mass)
Surfactant (fluorine-based, solid content concentration 10% by mass) 0.30 parts by mass

(Manufacturing of polyester film)
As a film raw material polymer, PET resin pellets (PET (II)) having an intrinsic viscosity (solvent: phenol / tetrachloroethane = 60/40) of 0.62 dl / g and substantially free of particles were used at 133 Pa. It was dried under reduced pressure at 135 ° C. for 6 hours. Then, it was supplied to an extruder, melt-extruded into a sheet at about 280 ° C., and rapidly cooled and solidified on a rotary cooled metal roll maintained at a surface temperature of 20 ° C. to obtain an unstretched PET sheet.

This unstretched PET sheet was heated to 100 ° C. with a heated roll group and an infrared heater, and then stretched 3.5 times in the longitudinal direction with a roll group having a peripheral speed difference to obtain a uniaxially stretched PET film.

Next, the easy-slip coating solution was applied to one side of the PET film with a bar coater, and then dried at 80 ° C. for 15 seconds. The coating amount after final stretching and drying was adjusted to 0.1 μm. Subsequently, with a tenter, the film was stretched 4.0 times in the width direction at 150 ° C., and with the length of the film fixed in the width direction, heated at 230 ° C. for 0.5 seconds, and further at 230 ° C. for 10 seconds 3 A relaxation treatment in the width direction of% was carried out to obtain an in-line coated polyester film having a thickness of 31 μm.

(Formation of release coating layer)
The release agent solution X-1 was applied to the surface of the in-line coated polyester film obtained above opposite to the laminated surface of the easy-to-slip coating layer with a reverse gravure coater so that the thickness after drying was 0.1 μm. Next, after drying with hot air at 90 ° C. for 30 seconds, immediately irradiate with ultraviolet rays (300 mJ / cm ² ) with an electrodeless lamp (H valve manufactured by Fusion Co., Ltd.) to form a release coating layer and ultra-thin ceramic green. A release film for sheet production was obtained. In addition, the process passability and handleability such as take-up property were excellent without any particular problem.

(Example 2)
Except for using the easy-slip coating solution 2 in which the silica particles B-3 in the easy-slip coating solution 1 used in Example 1 were changed to silica particles B-4 (average particle size 450 nm, solid content concentration 40% by mass). Obtained a release film for producing an ultra-thin ceramic green sheet in the same manner as in Example 1.

(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 easy-slip coating liquid 1 was changed to the following easy-slip coating liquid 3.
(Easy slip coating liquid 3)
Water 47.43 parts by mass Isopropyl alcohol 35.00 parts by mass Polyester aqueous dispersion Aw-1 14.92 parts by mass (solid content concentration 30% by mass)
Silica particles B-1 2.24 parts by mass (average particle size 40 nm, solid content concentration 20% by mass)
Silica particles B-4 0.11 parts by mass (average particle size 450 nm, solid content concentration 40% by mass)
Surfactant (fluorine-based, solid content concentration 10% by mass) 0.30 parts by mass

(Example 4)
A polyester film was obtained in the same manner as in Example 1 except that the easy-slip coating liquid 1 was changed to the following easy-slip coating liquid 4.
(Easy slip coating liquid 4)
Water 48.54 parts by mass Isopropyl alcohol 35.00 parts by mass Polyester aqueous dispersion Aw-1 14.92 parts by mass (solid content concentration 30% by mass)
Silica particles B-2 1.12 parts by mass (average particle size 100 nm, solid content concentration 40% by mass)
Silica particles B-4 0.11 parts by mass (average particle size 450 nm, solid content concentration 40% by mass)
Surfactant (fluorine-based, solid content concentration 10% by mass) 0.30 parts by mass

(Example 5)
A polyester film was obtained in the same manner as in Example 1 except that the easy-slip coating liquid 1 was changed to the following easy-slip coating liquid 5.
(Easy slip coating liquid 5)
Water 45.18 parts by mass Isopropyl alcohol 35.00 parts by mass Polyester aqueous dispersion Aw-2 18.93 parts by mass (solid content concentration 25% by mass)
Silica particles B-3 0.59 parts by mass (average particle size 200 nm, solid content concentration 40% by mass)
Surfactant (fluorine-based, solid content concentration 10% by mass) 0.30 parts by mass

(Example 6)
A polyester film was obtained in the same manner as in Example 1 except that the easy-slip coating liquid 1 was changed to the following easy-slip coating liquid 6.
(Easy slip coating liquid 6)
Water 51.32 parts by mass Isopropyl alcohol 35.00 parts by mass Polyurethane resin aqueous dispersion Aw-3 12.79 parts by mass (solid content concentration 37% by mass)
Silica particles B-3 0.59 parts by mass (average particle size 200 nm, solid content concentration 40% by mass)
Surfactant (fluorine-based, solid content concentration 10% by mass) 0.30 parts by mass

(Example 7)
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 coating layer was formed as follows.
(Formation of release coating layer)
The release agent solution X-2 was applied to the obtained in-line coated polyester film on the surface layer (a) opposite to the easy-slip coating layer with a reverse gravure coater so that the thickness after drying was 0.1 μm. Then, the release coating layer was formed by drying with hot air at 130 ° C. for 30 seconds to obtain a release film for producing an ultrathin ceramic green sheet.

(Example 8)
A polyester film was obtained in the same manner as in Example 1 except that the easy-slip coating liquid 1 was changed to the following easy-slip coating liquid 8.
(Easy slip coating liquid 8)
Water 46.56 parts by mass Isopropyl alcohol 35.00 parts by mass Polyester aqueous dispersion Aw-1 15.78 parts by mass (solid content concentration 30% by mass)
Acrylic particles B-5 2.37 parts by mass (average particle size 150 nm, solid content concentration 10% by mass)
Surfactant (fluorine-based, solid content concentration 10% by mass) 0.30 parts by mass

(Comparative Example 1)
As a film for forming a release coating layer, it was carried out except that it was changed to E5000-25 μm (manufactured by Toyobo) instead of the in-line coating film having an easy-slip coating layer on one surface prepared in Example 1. A release film for producing a ceramic green sheet was obtained in the same manner as in Example 1. E5000 contained particles inside the film, and Sa on both surfaces was 0.031 μm.

(Comparative Example 2)
A release film for producing a ceramic green sheet was obtained in the same manner as in Comparative Example 1 except that the coating thickness of the release layer was changed to 1.0 μm.

(Comparative Example 3)
As the film forming the release coating layer, instead of the in-line coating film having the easy-slip coating layer on one surface prepared in Example 1, the laminated film Z is used instead, and the lubricant of the film Z is contained. A release film for producing a ceramic green sheet was obtained in the same manner as in Example 1 except that a release coating layer was formed on the surface on the side not covered.

(Comparative Example 4)
Reverse gravure so that the back surface smoothing coating liquid Y has a thickness of 0.5 μm after drying on the surface opposite to the surface on which the release coating layer of the release film for manufacturing the ceramic green sheet obtained in Comparative Example 3 is formed. The film is applied with a coater, then dried with hot air at 90 ° C. for 30 seconds, and then immediately irradiated with ultraviolet rays (300 mJ / cm ² ) with an electrodeless lamp (H valve manufactured by Fusion Co., Ltd.) to form a back smoothing layer. Then, a release film for manufacturing a ceramic green sheet was obtained.

(Comparative Example 5)
A release film for producing a ceramic green sheet was obtained in the same manner as in Comparative Example 4 except that the back surface smoothing layer was coated to a thickness of 0.7 μm.

(Comparative Example 6)
A release film for producing a ceramic green sheet was obtained in the same manner as in Comparative Example 4 except that the back surface smoothing layer was coated to a thickness of 1.0 μm.

Table 1 shows the evaluation results of each Example and Comparative Example. As with Example 1, the take-up property, process passability, and handleability of each example were excellent without any particular problem.

In Examples 1 to 8, since all the parameters of Sa, P, and RSm on the surface of the easy-to-slip coating layer were in an appropriate range, a ceramic green sheet without pinholes could be obtained. In Comparative Examples 1 to 3, pinholes were observed because all the parameters of Sa, P, and RSm on the easy-slip surface were large. In Comparative Examples 4 to 6, Sa and P can be kept in an appropriate range by filling the unevenness of the easy-slip surface with a smoothing layer, but since RSm is large, it is not possible to suppress the occurrence of pinholes. It was enough. It is considered that a large RSm means that the protrusion spacing is wide and the number of protrusions per unit area is small, and the pressure applied to each protrusion is large, resulting in pinholes.

According to the present invention, there is provided a release film for manufacturing a ceramic green sheet that can achieve both good take-up property and prevention of pinholes and partial thickness variations even when the ceramic green sheet is thinned. Is possible. Further, by using the release film for producing a ceramic green sheet of the present invention, an ultrathin ceramic green sheet can be obtained, and a minute ceramic capacitor can be efficiently produced.

Claims (7)

A polyester film containing substantially no particles is provided as a base material, and an easy-slip coating layer is provided on one surface of the base material.
The polyester film is a polyester film containing at least one selected from polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate.
Average length of roughness curve element before Kieki lubricating coating layer (RSm) is 10μm or less,
Coated polyester film. Area average surface roughness of slipperiness coating layer (Sa) is 1nm or more 25nm or less, the coating polyester film according maximum projection height (P) is the請Motomeko 1 Ru der least 500nm or less 60 nm. Coating polyester film according to請Motomeko 1 or 2 thick Ru der least 2μm or less 0.001μm the slipperiness coating layer. The coated polyester film according to any one of claims 1 to 3 for producing a ceramic green sheet. A method for producing a ceramic green sheet using the coated polyester film according to any one of claims 1 to 4. Ceramic green sheet method according to請Motomeko 5 the thickness of the ceramic green sheet, Ru der than 2μm below 0.2μm to manufacture. Producing a ceramic green sheet method Rousset La ceramic capacitor to adopt a manufacturing method according to claim 5 or 6.