JPWO2019131449A1 - Release film for ceramic green sheet production - Google Patents

Abstract

An object of the present invention is to provide a release film for molding a ceramic green sheet which is excellent in peelability and hardly causes pinhole defects and damages such as cracks at the time of peeling in a molded ultra-thin ceramic green sheet. A release film in which a release layer having a thickness of 0.2 to 3.5 μm is laminated directly or via another layer on at least one surface of a polyester film, and the surface roughness of the surface of the release layer is provided. A release film for producing a ceramic green sheet, wherein (Sa) is 5 to 40 nm and the maximum peak height (Rp) is 60 nm or less. [Selection diagram] None

Description

  The present invention relates to a release film for manufacturing an ultra-thin ceramic green sheet, and more particularly, to a method for suppressing the occurrence of process defects due to pinholes and thickness unevenness or peeling failure during the production of an ultra-thin ceramic green sheet. The present invention relates to a release film for producing an ultra-thin ceramic green sheet which can be produced.

  2. Description of the Related Art Conventionally, a release film in which a release layer is laminated on a polyester film as a substrate has been used for forming a ceramic green sheet such as a multilayer ceramic capacitor (hereinafter referred to as MLCC), a ceramic substrate and the like. In recent years, the thickness of ceramic green sheets has tended to be reduced as the size and capacity of multilayer ceramic capacitors have increased. The ceramic green sheet is formed by applying a slurry containing a ceramic component such as barium titanate and a binder resin to a release film and drying the slurry. After printing an electrode on the molded ceramic green sheet and peeling it from the release film, the ceramic green sheet is laminated, pressed, cut, fired, and coated with an external electrode to produce a multilayer ceramic capacitor. Until now, when molding a ceramic green sheet on the release layer surface of a polyester film, minute projections on the release layer surface affect the molded ceramic green sheet, and defects such as cissing and pinholes are likely to occur. There was a problem. Therefore, various techniques for realizing a release layer surface having excellent flatness have been developed (for example, Patent Document 1).

  However, in recent years, ceramic green sheets have been further reduced in thickness, and ceramic green sheets having a thickness of 1.0 μm or less, more specifically, a thickness of 0.2 μm to 1.0 μm have been required. Therefore, higher smoothness has been required for the surface of the release layer. In addition, as the ceramic green sheet becomes thinner, the strength of the ceramic green sheet decreases, so not only the surface of the release layer is smoothed, but also the peeling force when the ceramic green sheet is peeled off from the release film is reduced and uniform. It is preferable to minimize the load applied to the ceramic green sheet when the ceramic green sheet is peeled from the release film so as not to damage the ceramic green sheet.

  As a method from the release layer side to smooth the release layer surface and to suppress the load on the ceramic green sheet during peeling, the release layer of the release film is formed by using an active energy ray-curable component. In order to increase the cross-linking density and improve the elastic modulus of the ceramic green sheet, measures for suppressing the elastic deformation of the release layer at the time of peeling the ceramic green sheet and reducing the peeling force have been studied (for example, Patent Documents 2 and 3). However, in this method, the surface was peeled because the smoothness was too high, the peeling force was increased, and cracks sometimes occurred in the green sheet. Furthermore, when the ultra-thin ceramic green sheet is processed, if the smooth surface comes in contact with a smooth roll or rubber roll for controlling the tension of the coating equipment, the slip control between the roll and the smooth surface is insufficient and the tension control becomes unstable, There was a problem that the smoothness of the green sheet application surface was reduced.

  Therefore, a release film having an excellent balance between smoothness and uniform release properties has been reported by using a polyester film having moderately large projections serving as a trigger at the start of peeling (peeling start point) (for example, , Patent Document 4). However, in the case of a filler kneaded in PET, coarse projections due to filler agglomeration cannot be completely eliminated, and there has been a problem of causing a defect of the product. In particular, in an ultra-thin ceramic green sheet, the inorganic filler used as a ceramic material has a particle size of about 60 nm to 800 nm (Patent Documents 5 and 6). There was a problem that a local hole was generated on the peeled surface.

JP 2000-117899 A International Publication No. WO 2013/145864 International Publication No. 2013/145865 International Publication No. WO 2014/203702 JP 2016-127120 A JP-A-2017-081805

  Therefore, the present inventors have conducted intensive studies, and as a result, by continuously forming low protrusions having a constant shape on the surface of the release layer, the above-described heavy separation, reduction in workability and occurrence of a defect factor have been solved. At the same time, we determined that it could be suppressed. Further, an object of the present invention is to provide a release film for forming a ceramic green sheet which is excellent in peelability and hardly causes a damage such as a pinhole defect and a crack at the time of peeling in a molded ultra-thin ceramic green sheet. It is.

That is, the present invention has the following configurations.
1. A release film in which a release layer of 0.2 to 3.5 μm is laminated on at least one surface of a polyester film directly or via another layer, wherein the surface roughness (Sa) of the release layer surface is A release film for producing a ceramic green sheet having a thickness of 5 to 40 nm and a maximum peak height (Rp) of 60 nm or less.
2. An energy ray-curable compound (I) in which a release layer has three or more reactive groups in one molecule; and the energy ray-curable compound (I), wherein the energy ray-curable compound (I) is a sea component. 2. The release film for producing a ceramic green sheet according to the above item 1, wherein a resin (II) which is incompatible with the resin and serves as an island component and a coating film containing at least a release component (III) are cured.
3. 3. The release film for producing a ceramic green sheet according to the above item 1 or 2, wherein the release layer contains substantially no inorganic particles.
4. The polyester film is a laminated polyester film comprising at least a surface layer A and two or more layers including a surface layer B opposite to the surface layer A, wherein a release layer is laminated on the surface layer A. 4. The release film for producing a ceramic green sheet according to any one of the first to third aspects, wherein the surface layer A contains substantially no inorganic particles.
5. The surface layer B contains particles, the particles are silica particles and / or calcium carbonate particles, and the content of the total particles is 5,000 to 15,000 ppm with respect to the total mass of the surface layer B according to the above item No. 4. Release film for manufacturing ceramic green sheets.
6. The polyester film according to any one of the first to third aspects, wherein the polyester film does not substantially contain inorganic particles, and the coating layer containing the particles is laminated on the side of the polyester film where the release layer is not laminated. Release film for manufacturing ceramic green sheets.
7. A method for producing a ceramic green sheet using the release film for producing a ceramic green sheet according to any one of the first to sixth aspects, wherein the molded ceramic green sheet has a thickness of 0.2 μm or more. A method for producing a ceramic green sheet having a thickness of 1.0 μm.

  According to the release film for manufacturing a ceramic green sheet of the present invention, the peeling force is not too heavy, the workability is excellent, and the projections on the release layer are large, as compared with the conventional release film for manufacturing a ceramic green sheet. Therefore, it has become possible to provide a release film for producing a ceramic green sheet which can reduce defects such as pinholes in an ultra-thin ceramic green sheet having a thickness of 1 μm or less.

  Hereinafter, the present invention will be described in detail.

  The release film for producing an ultra-thin ceramic green sheet of the present invention has a release layer directly or via another layer on at least one side of a polyester film, and the surface roughness of the release layer surface (Sa ) Is 5 to 40 nm, and the maximum peak height (Rp) is preferably 60 nm or less. The release layer has an energy ray-curable compound (I) having three or more reactive groups in one molecule, and a sea-island structure formed by phase separation that is incompatible with the energy ray-curable compound (I). In a preferred embodiment, a release film for producing a ceramic green sheet is obtained by curing a coating film containing at least a resin (II) for forming a resin and a release component (III).

(Polyester film)
The polyester constituting the polyester film used as the base material in the release film of the present invention is not particularly limited, and it is possible to use a polyester film that is generally used as a release film base film-formed. Preferably, it is a crystalline linear saturated polyester comprising an aromatic dibasic acid component and a diol component. For example, polyethylene terephthalate, polyethylene-2,6-naphthalate, polybutylene terephthalate, polytrimethylene terephthalate, or a mixture thereof. A copolymer containing the resin 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 at least 90 mol%, more preferably at least 95 mol%, and other dicarboxylic acid components and diol components may be copolymerized in small amounts, but from the viewpoint of cost. And those produced only from terephthalic acid and ethylene glycol. Known additives such as an antioxidant, a light stabilizer, an ultraviolet absorber, and a crystallization agent may be added as long as the effects of the film of the present invention are not impaired. The polyester film is preferably a polyester film because of the high elastic modulus in both directions.

  The intrinsic viscosity of the polyethylene terephthalate film is preferably from 0.50 to 0.70 dl / g, more preferably from 0.52 to 0.62 dl / g. When the intrinsic viscosity is 0.50 dl / g or more, it is preferable that breakage hardly occurs in the stretching step. Conversely, when it is 0.70 dl / g or less, it is preferable because the cutability when cutting into a predetermined product width is good and dimensional defects do not occur. Further, it is preferable that the raw material is sufficiently dried in vacuum.

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

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

  The polyester film preferably has a thickness of 12 to 50 μm, more preferably 12 to 38 μm, and still more preferably 15 to 31 μm. When the thickness of the film is 12 μm or more, there is no possibility of being deformed by heat at the time of film production, processing of a release layer, and molding of a ceramic green sheet, which is preferable. On the other hand, if the thickness of the film is 50 μm or less, the amount of the film to be discarded after use is not extremely large, which is preferable in reducing the environmental load. Further, the material per area of the release film to be used is small. Therefore, it is preferable from an economic viewpoint.

  The polyester film substrate may be a single layer or a multilayer of two or more layers, but may be a laminated polyester film having a surface layer A substantially free of inorganic particles on at least one surface. preferable. In the case of a laminated polyester film having a multilayer structure of two or more layers, it is preferable to have a surface layer B capable of containing particles and the like on the surface opposite to the surface layer A substantially containing no inorganic particles. As for the laminated structure, the layer on the side on which the release layer is applied is the surface layer A, the layer on the opposite side is the surface layer B, and the other core layers are the core layer C. / A surface layer A / a surface layer B or a release layer / a surface layer A / a core layer C / a surface layer B. Of course, the core layer C may have a plurality of layer configurations. Further, the surface layer B may not contain particles. In that case, it is preferable to provide a coat layer (D) containing particles and a binder on the surface layer B in order to provide slipperiness for winding the film into a roll.

  In the polyester film substrate of the present invention, the surface layer A forming the surface on which the release layer is applied preferably contains substantially no inorganic particles. At this time, the average surface roughness (Sa) of the surface layer A is preferably 7 nm or less. When Sa is 7 nm or less, even if the release layer has a film thickness of 2.0 μm or less, and even a thin film having a thickness of 0.5 μm or less, pinholes or the like occur when molding the super-thin ceramic green sheets to be laminated. It is difficult and preferable. It can be said that the smaller the area surface average roughness (Sa) of the surface layer A is, the more preferable it is, but it may be 0.1 nm or more. However, when an anchor coat layer or the like described below is provided on the surface layer A, it is preferable that the coat layer contains substantially no inorganic particles, and the area average surface roughness (Sa) after the coat layer is laminated is within the above range. Preferably, there is. In the present invention, "substantially free of inorganic particles" is defined as being 50 ppm or less when the inorganic element is quantified by fluorescent X-ray analysis, preferably 10 ppm or less, most preferably the detection limit or less. Content. This is because even if the inorganic particles are not positively added to the film, the contamination components derived from the foreign matter and the dirt attached to the raw material resin or the line or the device in the manufacturing process of the film are separated and mixed into the film. This is because there are cases.

  In the case where the polyester film substrate in the present invention is a laminated film, the surface layer B forming the opposite surface to the surface layer A on which the release layer is applied has a particle size in view of the slipperiness of the film and the ease of air release. , And particularly preferably silica particles and / or calcium carbonate particles. The content of the particles contained in the surface layer B is preferably 5,000 to 15,000 ppm in total. At this time, the surface average roughness (Sa) of the film of the surface layer B is preferably in the range of 1 to 40 nm. More preferably, it is in the range of 5 to 35 nm. When the total of the silica particles and / or calcium carbonate particles of the surface layer B is 5000 ppm or more and Sa is 1 nm or more, when the film is wound up into a roll, air can be uniformly released and the wound appearance is good. Good flatness makes it suitable for the production of ultra-thin ceramic green sheets. When the total of the silica particles and / or calcium carbonate particles is 15000 ppm or less and Sa is 40 nm or less, the aggregation of the lubricant hardly occurs, and coarse projections cannot be formed. In this case, it is preferable because defects such as pinholes do not occur in the ceramic green sheet.

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

  The average particle diameter of the particles added to the surface layer B is preferably from 0.1 μm to 2.0 μm, and particularly preferably from 0.5 μm to 1.0 μm. When the average particle diameter of the particles is 0.1 μm or more, the slipperiness of the release film is good, which is preferable. Further, when the average particle diameter is 2.0 μm or less, there is no possibility that pinholes due to coarse particles are generated on the surface of the release layer, which is preferable. The average particle diameter of the particles is measured by observing the particles on the cross section of the processed film with a scanning electron microscope, observing 100 particles, and using the average value as the average particle diameter. Can be. The shape of the particles is not particularly limited as long as the object of the present invention is satisfied, and spherical particles and irregular non-spherical particles can be used. The particle diameter of the amorphous particles can be calculated as a circle equivalent diameter. The equivalent circle diameter is a value obtained by dividing the area of the observed particle by the pi (π), calculating the square root, and doubling the square root.

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

  When particles are not contained in the surface layer B, it is also preferable that the coat layer containing the particles on the surface layer B has lubricity. The means for providing the present coat layer is not particularly limited, but is preferably provided by a so-called in-line coating method for applying during the production of a polyester film. In the case where a coat layer having lubricity is provided on the surface of the polyester film on the side where the release layer is not laminated, the polyester film does not need to have the surface layers A and B, and inorganic particles are substantially contained. It may be composed of a single-layer polyester film that is not contained in a specific way.

  The average surface roughness (Sa) of the surface layer B is preferably 40 nm or less, more preferably 35 nm or less, and still more preferably 30 nm or less. When the surface of the surface layer B or the surface of the single-layer polyester film on which the release layer is not laminated has a slipperiness with the coating layer (D), the surface Sa is measured by measuring the surface on which the coating layer is laminated. The average surface roughness (Sa) of the surface layer B is preferably in the same range as that described above.

(Coat layer D)
It is preferable that at least the binder resin and the particles are contained in the coat layer D on the surface of the polyester film on which the release layer is not laminated.

(Binder resin of coat layer D)
The binder resin constituting the slippery coating layer is not particularly limited, but specific examples of the polymer include a polyester resin, an acrylic resin, a urethane resin, a polyvinyl resin (eg, polyvinyl alcohol), a polyalkylene glycol, a polyalkyleneimine, and methylcellulose. , Hydroxycellulose, starch and the like. Among these, it is preferable to use a polyester resin, an acrylic resin, or a urethane resin from the viewpoint of retaining particles and adhesion. Further, in consideration of compatibility with the polyester film, a polyester resin is particularly preferable. In order to achieve solubility and dispersibility in a solvent and adhesion to a base film and other layers, the polyester of the binder is preferably a copolymer polyester. Incidentally, the polyester resin may be modified with polyurethane. Another preferred binder resin constituting the easily applied layer on the polyester base film is a urethane resin. Examples of the urethane resin include a polycarbonate polyurethane resin. Further, a polyester resin and a polyurethane resin may be used in combination, and the above-mentioned other binder resins may be used in combination.

(Crosslinking agent for coat layer D)
In the present invention, in order to form a crosslinked structure in the slippery coating layer, the slippery coating layer may be formed to contain a crosslinking agent. By including a crosslinking agent, it is possible to further improve the adhesion under high temperature and high humidity. Specific examples of the crosslinking agent include urea-based, epoxy-based, melamine-based, isocyanate-based, oxazoline-based, carbodiimide-based, and aziridine. In addition, a catalyst or the like can be appropriately used as needed to promote the crosslinking reaction.

(Particles in coat layer D)
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, Barium sulfate, carbon black, zinc oxide, zinc sulfate, zinc carbonate, zirconium oxide, titanium dioxide, satin white, aluminum silicate, diatomaceous earth, calcium silicate, aluminum hydroxide, hydrohaloysite, calcium carbonate, magnesium carbonate, calcium phosphate, hydroxylated 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 / Iso Organic particles such as len-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 exemplified, but are suitable for a coating layer. Silica is particularly preferably used to provide lubricity.

  The average particle size of the particles is preferably 10 nm or more, more preferably 20 nm or more, and even more preferably 30 nm or more. It is preferable that the average particle diameter of the particles is 10 nm or more, since the particles are hardly aggregated and the slipperiness can be secured.

  The average particle size of the particles is preferably 1000 nm or less, more preferably 800 nm or less, and even 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, mixing small particles having an average particle diameter of about 10 to 270 nm and large particles having an average particle diameter of about 300 to 1000 nm can also be achieved by the following method. It is preferable to reduce the average length (RSm) of the roughness curve element while keeping the RP) small, and to achieve both smoothness and smoothness. Particularly preferable are small particles of 30 nm or more and 250 nm or less, Large particles having a diameter of 350 to 600 nm are used in combination. When the small particles and the 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 entire solid content of the coating layer.

  From the viewpoint of reducing pinholes, it is preferable not to use a recycled material or the like in the surface layer A on the side where the release layer is provided, in order to prevent particles such as a lubricant from being mixed.

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

  In addition, from the viewpoint of economy, the layers other than the surface layer A (the surface layer B or the above-mentioned core layer C) can be made of 50 to 90% by mass of film waste or PET bottle recycled material. Even in this case, it is preferable that the type and amount of lubricant contained in the surface layer B, the particle diameter, and the average surface roughness (Sa) satisfy the above ranges.

  In addition, a film before or after uniaxial stretching in the film forming process is applied to the surface of the surface layer A and / or the surface layer B in order to improve the adhesion of a release layer or the like to be applied later or to prevent electrification. May be provided with a coat layer, or a corona treatment or the like may be performed. When a coat layer is also provided, the measured value of the surface of the coat layer is substituted for Sa of each layer. When these coat layers are provided on the surface of the surface layer A, it is preferable that no particles are contained.

(Release layer)
The release layer according to the present invention has an energy-ray-curable compound (I) having three or more reactive groups in one molecule, and is incompatible with the energy-ray-curable compound (I). It is preferable to cure a coating film containing at least the resin (II) forming the resin and the release component (III). Since the energy ray-curable compound (I) and the resin (II) phase-separate to form a sea-island structure, irregularities of moderate height can be easily formed and coarse projections do not occur. No holes are generated. In addition, since the flat portion is almost eliminated, and peeling is performed at a point, even a brittle ultra-thin ceramic green sheet can be peeled without zipping, thereby suppressing damage such as cracks and deformation. .

(Energy ray-curable compound (I) having three or more reactive groups in one molecule)
As the energy ray-curable compound (I) used in the present invention, an energy ray-curable compound having three or more reactive groups in one molecule can be used. By having three or more reactive groups in one molecule, a release layer having a high elastic modulus can be obtained, and deformation of the release layer at the time of peeling the green sheet can be suppressed, and heavy release can be suppressed. In addition, since the solvent resistance of the release layer can be improved, erosion of the release layer by a solvent at the time of slurry application can be prevented, which is preferable. The energy ray-curable compound having three or more reactive groups in one molecule is not particularly limited as to whether it reacts directly with an energy ray or reacts with an indirectly generated active species. The content of the energy ray-curable compound (I) in the solid content in the coating solution for forming a release layer is preferably from 60 to 98% by mass, and more preferably from 75 to 97% by mass. By adding 60% by mass or more, the degree of crosslinking can be maintained and a high elastic modulus can be obtained.

  Examples of the reactive group of the energy ray-curable compound (I) include a (meth) acryloyl group, an alkenyl group, an acrylamide group, a maleimide group, an epoxy group, and a cyclohexene oxide group. Among them, an energy ray-curable compound having a (meth) acryloyl group having excellent workability is preferable.

  The energy ray-curable compound having a (meth) acryloyl group can be used without being limited to a monomer, an oligomer or a polymer. In addition, it is preferable to contain at least one compound having three or more reactive groups in one molecule, but two or more compounds such as compounds having one to two reactive groups in a molecule are used as a mixture. You can also. By mixing these compounds having a small number of reactive groups, curling and the like can be suppressed.

  Examples of energy ray-curable monomers having three or more (meth) acryloyl groups in the molecule include isocyanuric acid triacrylate, glycerin tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, Methylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) ) Polyfunctional (meth) acrylates such as acrylates and their ethylene oxide modified products, propylene oxide modified products, caprolactone modified products, etc. .

  Examples of the energy ray-curable monomer having 1 to 2 reactive groups in the molecule include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, Isobutyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, cyclopentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, Nonyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, isobornyl (meth) acrylate, cyclic trimethylolpropane formal (Meth) acrylate, hydroxyethyl (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxypropyl (meth) acrylate, (meth) acrylic acid, dicyclopentenyloxyethyl (meth) acrylate, dicyclopentanyl (meth) acrylate, Benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, pentamethylpiperidinyl (meth) acrylate, tetramethylpiperidinyl (meth) acrylate, 1 , 4-butanediol di (meth) acrylate, polyethylene glycol di (meth) acrylate, nonanediol di (meth) acrylate, bisphenol A di (meth) acrylate Rate, neopentyl glycol di (meth) acrylate, monomers and their ethylene oxide-modified products such as cyclohexane diol di (meth) acrylate, propylene oxide-modified products, caprolactone-modified products, and the like.

  Examples of energy ray-curable oligomers having three or more (meth) acryloyl groups in the molecule include urethane acrylate, polyester acrylate, polyether acrylate, epoxy acrylate, and silicone-modified acrylate, and those commercially available are generally available. Can be used. For example, beam set (registered trademark) series manufactured by Arakawa Chemical Industry Co., Ltd., NK oligo series manufactured by Shin-Nakamura Chemical Co., EBECRYL series manufactured by Daicel Ornex, Biscoat series manufactured by Osaka Organic Chemical Industry Co., Ltd., urethane acrylate series manufactured by Kyoeisha Chemical Co., Ltd., DIC's Unidick series.

  Examples of the energy ray-curable polymers having three or more (meth) acryloyl groups in the molecule include a graft polymer obtained by grafting a (meth) acryloyl group to a polymer and a block polymer obtained by adding a polyfunctional acrylic monomer to a polymer terminal. Is mentioned. As the above-mentioned polymers, an acrylic resin, an epoxy resin, a polyester resin, a polyorganosiloxane, or the like can be used, and is not particularly limited.

(Resin (II))
The resin (II) used in the present invention is dissolved or dispersed in the same solvent as the energy ray-curable compound (I), and in the state of a coating agent, both are dissolved or dispersed. In the release layer formed through curing, it is incompatible with each other, and it is preferable to form a sea-island structure using the energy ray-curable compound (I) as a sea component and the resin (II) as an island component. (II) can be used without particular limitation as long as the above requirements are satisfied. Two or more resins can be used simultaneously. The content of the resin (II) in the solid content of the coating solution for forming a release layer is preferably 1 to 40% by mass, and more preferably 1 to 10% by mass. When the content is 1% by mass or more, sufficient unevenness can be formed, and when the content is 40% by mass or less, the degree of crosslinking of the release layer is high, and the temperature dependency at the time of peeling is low, which is preferable.

  As the resin (II), for example, a polyester resin, an acrylic resin, a urethane resin, a polyester urethane resin, a polyimide resin, a polyamideimide resin, a cellulose resin, and the like can be used without particular limitation as long as the solvent is soluble. The condition is that the resin is incompatible with the energy ray-curable compound (I).

  The polyester resin is not particularly limited, and a commercially available polyester resin can be used. Examples include the Byron (registered trademark) series manufactured by Toyobo and the Nichigo Polyester (registered trademark) series manufactured by Nippon Synthetic Chemical Industry.

  The acrylic resin refers to an oligomer or polymer obtained by polymerizing an acrylate, and may be a homopolymer or a copolymer. Also, commercially available products can be used. For example, an Acridic (registered trademark) series manufactured by DIC Corporation, an ARFON (registered trademark) series manufactured by Toagosei Co., Ltd., and the like can be given.

  Examples of the polyester urethane resin include Byron (registered trademark) UR series manufactured by Toyobo.

(Release component (III))
The release component (III) used in the present invention is not particularly limited as long as it is a material such as polyorganosiloxane, a fluorine compound, a long-chain alkyl compound, and waxes that can exhibit release properties with a green sheet. Further, a material having a functional group which can react with and bond to the energy ray-curable compound (I) having a (meth) acryloyl group or the like is preferable. Further, two or more kinds of materials can be mixed and used. The content of the release component (III) in the solid content in the coating liquid for forming a release layer is preferably 0.05 to 10% by mass, more preferably 0.1 to 5% by mass. Addition of 0.05% by mass or more is preferred because the peeling force can be reduced and 10% by mass or less can suppress the transfer of the release component to the ceramic green sheet or the like.

  Examples of the polyorganosiloxane include polydimethylsiloxane, polydiethylsiloxane, polyphenylsiloxane, a partially organically modified siloxane-based compound, a block polymer having a polyorganosiloxane, and a polymer obtained by grafting a polyorganosiloxane. Can be used. As commercially available products, for example, BYK (registered trademark) series manufactured by BYK Japan KK and Modiper (registered trademark) series manufactured by NOF Corporation can be used.

  The fluorine compound is not particularly limited, and a commercially available one can be used. For example, there is a MegaFac (registered trademark) series manufactured by DIC Corporation.

  Examples of the long-chain alkyl compound include an acrylic polymer obtained by copolymerizing a long-chain alkyl acrylate, a graft polymer obtained by grafting a long-chain alkyl, and a block polymer having a long-chain alkyl added to a terminal. There is no particular limitation, and commercially available products can be used. Examples include the Tesfine (registered trademark) series manufactured by Hitachi Chemical Co., Ltd., and Peiroyl (registered trademark) manufactured by Lion Specialty Chemicals.

  Examples of the active energy rays include infrared rays, visible rays, ultraviolet rays, electromagnetic waves such as X-rays, electron beams, ion beams, neutron rays, and particle rays such as α rays. It is preferable to use excellent ultraviolet light.

  The atmosphere for irradiating the active energy ray may be general air or nitrogen gas atmosphere. In a nitrogen gas atmosphere, the radical reaction can proceed smoothly by reducing the oxygen concentration and the elastic modulus of the release layer can be improved. It is preferable to do so from an economic viewpoint.

(Photopolymerization initiator)
When a radical polymerization compound is used in the release layer of the present invention, it is preferable to add a photopolymerization initiator. Specific examples of the photopolymerization initiator include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, methyl benzoin benzoate, benzoin dimethyl ketal, and 2,4. -Diethylthioxanthone, 1-hydroxycyclohexylphenylketone, benzyldiphenylsulfide, tetramethylthiurammonosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, β-chloranthraquinone, (2,4,6-trimethyl (Benzyldiphenyl) phosphine oxide, 2-benzothiazole-N, N-diethyldithiocarbamate and the like. In particular, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] -phenyl} -2-methylpropan-1-one, which is considered to have excellent surface curability, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1 -One is preferable, and 2-hydroxy-2-methyl-1-phenyl-propan-1-one and 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one are particularly preferable. preferable. These may be used alone or in combination of two or more.

  The amount of the photopolymerization initiator to be added is not particularly limited. For example, it is preferable that the photopolymerization initiator be contained in an amount of about 0.1 to 20% by mass as a solid content in the coating solution for forming a release layer.

  The release layer in the present invention may contain particles having a particle diameter of 1 μm or less, but it is preferable not to contain particles that form projections such as particles from the viewpoint of pinhole generation.

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

  In the present invention, the thickness of the release layer may be set according to the purpose of use, and is not particularly limited. Preferably, the release layer after curing has a range of 0.2 to 3.5 μm. More preferably, it is 0.5 to 3.0 μm. When the thickness of the release layer is 0.2 μm or more, the curability of the energy ray-curable copolymer is good, and the elasticity of the release layer is improved, so that good release performance is obtained, which is preferable. Further, when the thickness is 3.5 μm or less, curling hardly occurs even when the thickness of the release film is reduced, and the running property is not deteriorated in the process of molding and drying the ceramic green sheet, which is preferable.

  In the release film of the present invention, the surface of the release layer preferably has moderate unevenness. Therefore, it is preferable that the average surface roughness (Sa) of the release layer surface is 5 to 40 nm. Further, it is more preferable that the above-mentioned Sa is satisfied and the maximum projection height (Rp) of the surface of the release layer is 60 nm or less. Further, the average surface roughness (Sa) of the region is preferably from 5 to 20 nm, more preferably from 8.5 to 20 nm. At that time, it is particularly preferable that the maximum projection height (Rp) be 50 nm or less. If the area surface roughness (Sa) is 5 nm or more, zipping is reduced when the ceramic green sheet is peeled, and even an ultrathin green sheet can be easily peeled without damage. If the surface roughness of the region (Sa) is 40 nm or less, it is sufficiently smaller than the particle size of the ceramic, and does not affect the surface shape of the green sheet. It is preferable that the above-mentioned Sa is satisfied and the maximum protrusion height (Rp) of the release layer surface is 60 nm or less, since the possibility of causing pinhole defects is further reduced. Although the maximum protrusion height (Rp) is preferably small, the maximum protrusion height (Rp) may be 5 nm or more, or may be 10 nm or more, because the average surface roughness (Sa) is adjusted to 5 nm or more. It does not matter. Various factors are involved in adjusting the surface roughness (Sa) and the maximum projection height (Rp) of the release layer as described above, but mainly the surface layer A of the polyester film is adjusted. Or, since the single-layer polyester film does not substantially contain inorganic particles, the surface of the release layer having a low layer roughness is small, and the release layer has three or more reactive groups in one molecule. A curable compound (I) and the energy ray-curable compound (I) as a sea component, and a resin (II) which is incompatible with the energy ray-curable compound (I) and becomes an island component and cured. It can be said that what is being done is related. The method for adjusting the surface roughness (Sa) and the maximum protrusion height (Rp) of the release layer to the appropriate ranges as described above is not particularly limited, but mainly the energy ray-curable compound (I) and the resin ( It can be preferably achieved by adjusting the combination of materials and the content ratio of II).

The coefficient of static friction of the release layer surface of the release layer film of the present invention is preferably 0.05 or more and 2.00 or less. It is more preferably 0.1 or more and 1.00 or less, and further preferably 0.1 or more and 0.50 or less. If the coefficient of static friction is within the above range, the roll between the coating equipment and the release layer surface slides well, and excessive force is not applied, so that damage to the release layer surface is reduced and damage to the green sheet is reduced. And a good green sheet surface can be obtained.
Further, the dynamic friction coefficient of the surface of the release layer of the release film of the present invention is preferably 1.00 or less. Within the above range, a good green sheet surface can be obtained without causing tension abnormality in the process.
The adjustment to the range of the static friction coefficient and the dynamic friction coefficient of the release layer surface has a relationship with the range of the surface roughness (Sa) and the maximum protrusion height (Rp) of the release layer. Although not particularly limited, it can be preferably achieved mainly by adjusting the combination and content ratio of the materials of the energy ray-curable compound (I) and the resin (II).

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

When the release layer of the present invention is applied on a substrate film by solution coating, the drying temperature of solvent drying is preferably 50 ° C or more and 120 ° C or less, and is preferably 60 ° C or more and 100 ° C or less. More preferred. The drying time is preferably 30 seconds or less, more preferably 20 seconds or less. Further, it is preferable that after the solvent is dried, the curing reaction proceeds by irradiating with an active energy ray. As the active energy ray used at this time, an ultraviolet ray, an electron beam, an X-ray, or the like can be used. Preferably 30~300mJ / cm ² in quantity as the amount of ultraviolet rays to be irradiated, more preferably 30~200mJ / cm ^2. Curing proceed sufficiently in composition by a 30 mJ / cm ² or more, it is possible to create economically release film it is possible to improve the speed during processing by a 300 mJ / cm ² or less 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 setting the surface tension as described above, the wettability after coating is improved, and the unevenness of the coating film surface after drying can be reduced.

  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, and an air knife. A conventionally known method such as a coating method can be used.

  EXAMPLES The present invention will be described in detail with reference to examples below, but the present invention is not limited to these examples. The characteristic values used in the present invention were evaluated using the following methods. Hereinafter, the weight average molecular weight may be simply referred to as Mw.

(1) Base film thickness Using a Millitron (electronic microindicator), four 5 cm square samples are cut out from any four points of the film to be measured, and each point is measured at 5 points (20 points in total) and averaged. Is the thickness.

(2) Release Layer Thickness The thickness of the release layer was measured using a light interference type film thickness meter (F20, manufactured by Filmetrics). (The refractive index of the release layer is calculated as 1.52)

(3) Area surface roughness (Sa), maximum projection height (Rp)
It is a value measured under the following conditions using a non-contact surface shape measurement system (VertScan R550H-M100, manufactured by Ryoka Systems Inc.). The average value of five measurements was adopted as the average surface roughness of the area (Sa), and the maximum protrusion height (Rp) was measured seven times, and the maximum value of five times excluding the maximum value and the minimum value was used.
(Measurement condition)
・ Measurement mode: WAVE mode ・ Objective lens: 50 × ・ 0.5 × Tube lens (Analysis conditions)
・ Surface correction: 4th order correction ・ Interpolation processing: Complete interpolation

(4) Pinhole Evaluation of Ceramic Green Sheet A composition comprising the following materials was stirred and mixed, and dispersed for 60 minutes using a bead mill using zirconia beads having a diameter of 0.5 mm as a dispersion medium to prepare a ceramic slurry.
76.3 parts by mass of toluene 76.3 parts by mass of ethanol 76.3 parts by mass of barium titanate (HPBT-1 manufactured by Fuji Titanium Co., Ltd.) 35.0 parts by mass 3.5 parts by mass of polyvinyl butyral 3.5 parts by mass (ESLEC (registered trademark) BM-S manufactured by Sekisui Chemical Co., Ltd.) )
1.8 parts by mass of DOP (dioctyl phthalate) Next, the release surface of the release film sample is coated using an applicator so that the dried ceramic green sheet has a thickness of 0.8 μm, and dried at 90 ° C. for 2 minutes. The release film was peeled off to obtain a ceramic green sheet.
In the center region of the obtained ceramic green sheet in the film width direction, light is applied from the opposite surface of the ceramic slurry application surface in a range of 25 cm ² , and the state of occurrence of pinholes through which light is visible is observed. It was visually determined. The measurement was performed five times and the average value was adopted.
○: Almost no pinholes (approximate: 2 or less pinholes per measurement area)
△: Pinholes are generated (approximate: 3 or more pinholes per measurement area) ×: Many pinholes are generated (approximate: 6 or more pinholes per measurement area)

(5) Evaluation of Damage to Ceramic Green Sheet The release film with the ceramic green sheet prepared by the above method was cut into a width of 30 mm and a length of 80 mm to obtain a sample for measuring a peeling force. After static elimination using a static eliminator (manufactured by Keyence Corporation, SJ-F020), using a peeling tester (VPA-3, manufactured by Kyowa Interface Science Co., Ltd.), a peeling angle of 30 °, a peeling temperature of 25 ° C, and a peeling speed of 10 m / min. The peeling direction was such that a double-sided adhesive tape (No. 535A, manufactured by Nitto Denko Corporation) was attached to the SUS plate attached to the peeling tester, and the ceramic green sheet side was bonded to the double-sided tape on top of that. Was fixed and peeled off by pulling the release film side. With respect to the surface of the ceramic green sheet after peeling which was in contact with the release film, a range of 1250 μm × 900 μm was observed 100 times with a scanning electron microscope in the central region in the film width direction, and an average value measured ten times was adopted. . It was visually determined according to the following criteria.

：: No damage at the time of peeling (approximate: No crack and no deformation)
△: slight damage at peeling (approximate: cracks and deformations are 1 to 3 per measurement area)
×: Severe damage during peeling (approximate: 4 or more cracks and deformations)

The peel angle in the present evaluation method refers to the angle in the direction in which the release film is pulled with respect to the evaluation sample axis fixed to the peel tester. The peeling temperature is a temperature when the fixed release film is heated using a heater type stage system attached to the apparatus. The peeling is performed after confirming that the measurement sample has reached the corresponding temperature using a handy type thermometer (HD-1400E manufactured by Anritsu Keiki Co., Ltd.).

(6) Coefficient of static friction and coefficient of dynamic friction When using a Tensilon universal tester (RTG-1210, manufactured by A & D Corporation), the surface of the release layer of the film and the SUS plate are superimposed so as to be in contact with each other. The static friction coefficient (μs) and the dynamic friction coefficient (μd) of the contact surface were measured under the following conditions in accordance with JIS K-7125.

Test piece: width 50 mm x length 60 mm
Load: 4.4kg
Test speed: 200mm / min
Material to be frictioned: SUS plate

(Preparation of polyethylene terephthalate pellet (PET (1)))
As the esterification reactor, a continuous esterification reactor consisting of a three-stage complete mixing tank having a stirrer, a decomposer, a raw material inlet, and a product outlet was used. TPA (terephthalic acid) was set at 2 tons / hour, EG (ethylene glycol) was set at 2 moles with respect to 1 mole of TPA, antimony trioxide was used in such an amount that Sb atoms became 160 ppm with respect to generated PET, and these slurries were esterified. The mixture was continuously supplied to the first esterification reactor of the conversion reaction apparatus, and reacted at 255 ° C. at ordinary pressure for 4 hours on average. Next, the reaction product in the first esterification reactor is continuously taken out of the system and supplied to the second esterification reactor, and is distilled from the first esterification reactor into the second esterification reactor. EG solution containing magnesium acetate tetrahydrate in an amount such that Mg atoms become 65 ppm with respect to the generated PET, and 40 ppm with P atoms with respect to the generated PET. An EG solution containing the following amount of TMPA (trimethyl phosphate) was added and reacted at 260 ° C. for 1 hour at an average residence time at normal pressure. Next, the reaction product of the second esterification reactor is continuously taken out of the system and supplied to the third esterification reactor, 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 subjected to dispersion treatment with an average number of treatments of 5 passes at a pressure of 5%, and 1% by mass of ammonium salt of polyacrylic acid per 1% by mass of calcium carbonate While adding 0.4% by mass of synthetic calcium carbonate having a diameter of 0.6 μm as EG slurries of 10% each, the mixture was reacted at 260 ° C. and an average residence time of 0.5 hour at normal pressure. The esterification reaction product generated in the third esterification reaction vessel was continuously supplied to a three-stage continuous polycondensation reaction apparatus to perform polycondensation, and sintered a stainless steel fiber having a 95% cut diameter of 20 μm. After filtration with a filter, ultrafiltration was performed and the mixture was extruded into water. After cooling, the mixture was cut into chips to obtain a PET chip having an intrinsic viscosity of 0.60 dl / g (hereinafter abbreviated as PET (1)). . The lubricant content in the PET chip was 0.6% by mass.

(Preparation of polyethylene terephthalate pellet (PET (2)))
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 (2)).

(Preparation of polyethylene terephthalate pellet (PET (3)))
Except that the type and content of the particles of PET (I) were changed to 0.75 mass% of synthetic calcium carbonate having an average particle diameter of 0.9 μm obtained by adhering ammonium salt of polyacrylic acid at 1 mass% per calcium carbonate. A PET chip was obtained in the same manner as in PET (1) (hereinafter abbreviated as PET (3)). The lubricant content in the PET chip was 0.75% by mass.

(Production of laminated film X1)
After drying these PET chips, they are melted at 285 ° C., melted at 290 ° C. by a separate melt extruder extruder, and a filter obtained by sintering a stainless steel fiber having a 95% cut diameter of 15 μm; Two-stage filtration of a filter in which 15 μm stainless steel particles are sintered is performed, and the two are merged in a feed block. PET (1) has a surface layer B (anti-release surface side layer) and PET (2) has a surface. The layers are laminated so as to become the layer A (release side layer), extruded (casted) at a speed of 45 m / min into a sheet, electrostatically adhered and cooled on a casting drum at 30 ° C. by an 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 (1) / (2) = 60% / 40% in the discharge amount calculation of each extruder. Next, the unstretched sheet was heated by an infrared heater, and then stretched 3.5 times in the longitudinal direction at a roll temperature of 80 ° C. due to a speed difference between the rolls. Then, it was guided to a tenter and stretched 4.2 times in the transverse direction at 140 ° C. Next, heat treatment was performed at 210 ° C. in the heat setting zone. Thereafter, a relaxation treatment of 2.3% was performed in the horizontal direction at 170 ° C. to obtain a biaxially stretched polyethylene terephthalate film X1 having a thickness of 31 μm. Sa of the surface layer A of the obtained film X1 was 2 nm, and Sa of the surface layer B was 29 nm.

(Production of laminated film X2)
The thickness was adjusted by changing the speed at the time of casting without changing the same layer configuration and stretching conditions as those of the laminated film X1, to obtain a biaxially stretched polyethylene terephthalate film X2 having a thickness of 25 μm. Sa of the surface layer A of the obtained film X2 was 3 nm, and Sa of the surface layer B was 29 nm.

(Laminated film X3)
A4100 (Cosmoshine (registered trademark), manufactured by Toyobo Co., Ltd.) having a thickness of 25 μm was used as the laminated film X3. A4100 has a structure in which particles are not substantially contained in the film, and a coating layer containing particles is provided on the surface layer B side by in-line coating. Sa of the surface layer A of the laminated film X3 was 1 nm, and Sa of the surface layer B was 2 nm.

(Example 1)
A coating solution 1 having the following composition is applied on the surface layer A of the laminated film X1 using reverse gravure so that the thickness of the release layer after drying is 2.5 μm, and dried at 90 ° C. for 30 seconds. Ultraviolet rays were irradiated to 200 mJ / cm ² using a mercury lamp to obtain a release film for producing an ultra-thin ceramic green sheet. About the obtained release film, release layer thickness, area surface roughness Sa, maximum protrusion height Rp, pinhole evaluation of ceramic green sheet, damage evaluation to ceramic green sheet, static friction coefficient, and dynamic friction coefficient were evaluated. Was.

(Coating liquid 1)
Compound (I) 100.00 parts by mass
(Dipentaerythritol hexaacrylate, A-DPH manufactured by Shin-Nakamura Chemical Co., Ltd., solid content concentration 100%)
Resin (II) 9.47 parts by mass of polyester resin (Vylon (registered trademark) RV280 manufactured by Toyobo Co., solid content concentration: 100% by mass)
1.26 parts by mass of release agent (III) (modified polydimethylsiloxane having an acryloyl group, BYK-UV3505, manufactured by BYK Japan KK, solid content concentration 40% by mass)
5.25 parts by mass of photopolymerization initiator (OMNIRAD (registered trademark) 907, manufactured by IGM Japan GK, solid content concentration 100% by mass)
Diluent solvent (MEK / toluene = 1/1) 459.79 parts by mass

(Example 2)
The resin (II) was changed to a polyester urethane resin (manufactured by Toyobo Co., Ltd., Byron (registered trademark) UR1400, solid content concentration: 30% by mass), and the following coating solution 2 was used. The solid content concentration of the coating solution 2 was reduced as compared with the coating solution 1 of Example 1. Coating was performed so that the thickness of the release layer after drying was 1.5 μm. A release film was obtained in the same manner as in Example 1, except that the coating liquid 2 was used and the coating was performed so that the thickness of the release layer after drying was 1.5 μm. For the obtained release film, the release layer thickness, the area surface roughness Sa, the maximum protrusion height Rp, the pinhole evaluation of the ceramic green sheet, the damage to the ceramic green sheet, the static friction coefficient, and the dynamic friction coefficient were evaluated. Was.

(Coating liquid 2)
100.00 parts by mass of compound (I) (dipentaerythritol hexaacrylate, A-DPH manufactured by Shin-Nakamura Chemical Co., Ltd., solid content concentration 100%)
Resin (II) 31.50 parts by mass of polyester urethane resin (Vylon (registered trademark) UR1400 manufactured by Toyobo Co., solid content concentration: 30% by mass)
Release agent (III) 0.42 parts by mass (modified polydimethylsiloxane having an acryloyl group, BYK-UV3505, manufactured by BYK Japan KK, solid content concentration 40% by mass)
5.25 parts by mass of photopolymerization initiator (OMNIRAD (registered trademark) 907, manufactured by IGM Japan GK, solid content concentration 100% by mass)
975.42 parts by mass of a diluting solvent (MEK / toluene = 1/1)

(Example 3)
The following coating liquid 3 in which the ratio of the release agent (III) was increased as compared with Example 2 was used. Coating was performed so that the thickness of the release layer after drying was 1.8 μm. A release film was obtained in the same manner as in Example 1, except that the coating liquid 3 was used and the coating was performed so that the thickness of the release layer after drying was 1.8 μm. For the obtained release film, the release layer thickness, the area surface roughness Sa, the maximum protrusion height Rp, the pinhole evaluation of the ceramic green sheet, the damage to the ceramic green sheet, the static friction coefficient, and the dynamic friction coefficient were evaluated. Was.

(Coating liquid 3)
100.00 parts by mass of compound (I) (dipentaerythritol hexaacrylate, A-DPH manufactured by Shin-Nakamura Chemical Co., Ltd., solid content concentration 100%)
Resin (II) 31.50 parts by mass of polyester urethane resin (Vylon (registered trademark) UR1400 manufactured by Toyobo Co., solid content concentration: 30% by mass)
1.26 parts by mass of release agent (III) (modified polydimethylsiloxane having an acryloyl group, BYK-UV3505, manufactured by BYK Japan KK, solid content concentration 40% by mass)
5.25 parts by mass of photopolymerization initiator (OMNIRAD (registered trademark) 907, manufactured by IGM Japan GK, solid content 100% by mass)
Diluent solvent (MEK / toluene = 1/1) 982.98 parts by mass

(Example 4)
The coating liquid 3 used in Example 3 was applied on the surface layer A of the laminated film X2. A release film was obtained in the same manner as in Example 3, except that the laminated film X2 was used. For the obtained release film, the release layer thickness, the area surface roughness Sa, the maximum protrusion height Rp, the pinhole evaluation of the ceramic green sheet, the damage to the ceramic green sheet, the static friction coefficient, and the dynamic friction coefficient were evaluated. Was.

(Example 5)
The coating liquid 3 used in Example 3 was applied on the surface layer A of the laminated film X3. A release film was obtained in the same manner as in Example 3, except that the laminated film X3 was used. For the obtained release film, the release layer thickness, the area surface roughness Sa, the maximum protrusion height Rp, the pinhole evaluation of the ceramic green sheet, the damage to the ceramic green sheet, the static friction coefficient, and the dynamic friction coefficient were evaluated. Was.

(Comparative Example 1)
Compared to Example 1, the resin (II) is not contained, and the release agent (III) is a polyether-modified polydimethylsiloxane containing an acryloyl group (BYK UV-3500, manufactured by Big Chemie Japan, and having a solid content of 100%). The following coating solution 4 was used in which the amount of addition was increased and the dilution solvent was changed. A release film was obtained in the same manner as in Example 1, except that the coating liquid 4 was used and that the release layer thickness after drying was 1.0 μm. For the obtained release film, the release layer thickness, the area surface roughness Sa, the maximum protrusion height Rp, the pinhole evaluation of the ceramic green sheet, the damage to the ceramic green sheet, the static friction coefficient, and the dynamic friction coefficient were evaluated. Was.

(Coating liquid 4)
100.00 parts by mass of compound (I) (dipentaerythritol hexaacrylate, A-DPH manufactured by Shin-Nakamura Chemical Co., Ltd., solid content concentration 100%)
1.00 parts by mass of release agent (III) (acryloyl group-containing polyether-modified polydimethylsiloxane BYK UV-3500, manufactured by Big Chemie Japan, solid content: 100%)
5.00 parts by mass of photopolymerization initiator (OMNIRAD (registered trademark) 907, manufactured by IGM Japan GK, solid content concentration: 100% by mass)
424.25 parts by mass of diluting solvent (IPA / MEK = 3/1)

  According to the release film for producing a ceramic green sheet of the present invention, the release force does not become too heavy, the workability is excellent, and the release layer is large as compared with the conventional release film for producing a ceramic green sheet. Since there are no protrusions, it has become possible to provide a release film for producing a ceramic green sheet which can reduce defects such as pinholes in an ultra-thin ceramic green sheet having a thickness of 1 μm or less.

Claims (7)

  A release film in which a release layer of 0.2 to 3.5 μm is laminated on at least one surface of a polyester film directly or via another layer, wherein the surface roughness (Sa) of the release layer surface is A release film for producing a ceramic green sheet having a thickness of 5 to 40 nm and a maximum peak height (Rp) of 60 nm or less.   An energy ray-curable compound (I) in which a release layer has three or more reactive groups in one molecule; and the energy ray-curable compound (I), wherein the energy ray-curable compound (I) is a sea component. The release film for producing a ceramic green sheet according to claim 1, wherein a coating film containing at least a resin (II) which is incompatible with and which is an island component and a release component (III) is cured.   The release film for producing a ceramic green sheet according to claim 1 or 2, wherein the release layer contains substantially no inorganic particles.   The polyester film is a laminated polyester film comprising at least a surface layer A and two or more layers including a surface layer B opposite to the surface layer A, wherein a release layer is laminated on the surface layer A. The release film for producing a ceramic green sheet according to any one of claims 1 to 3, wherein the surface layer A contains substantially no inorganic particles.   The surface layer B contains particles, the particles are silica particles and / or calcium carbonate particles, and the total content of the particles is 5,000 to 15,000 ppm based on the total mass of the surface layer B. Release film for manufacturing ceramic green sheets.   The ceramic according to any one of claims 1 to 3, wherein the polyester film does not substantially contain inorganic particles, and a coating layer containing particles is laminated on a side of the polyester film where the release layer is not laminated. Release film for manufacturing green sheets.   A method for producing a ceramic green sheet using the release film for producing a ceramic green sheet according to claim 1, wherein the molded ceramic green sheet has a thickness of 0.2 μm to 1 μm. A method for producing a ceramic green sheet having a thickness of 0.0 μm.