JP6822549B2 - Release film for manufacturing ceramic green sheets - Google Patents

Description

The present invention relates to a release film for manufacturing an ultra-thin layer ceramic green sheet, and more specifically, a film that suppresses the occurrence of process defects due to pinholes, uneven thickness, and poor peeling during the production of an ultra-thin layer ceramic green sheet. It relates to a mold release film for manufacturing an ultra-thin ceramic green sheet that can be manufactured.

Conventionally, a release film obtained by laminating a release layer on a polyester film as a base material is used for molding a ceramic green sheet such as a laminated ceramic capacitor (hereinafter referred to as MLCC) and a ceramic substrate. In recent years, with the miniaturization and large capacity of multilayer ceramic capacitors, the thickness of the ceramic green sheet tends to be reduced. The ceramic green sheet is molded by applying a slurry containing a ceramic component such as barium titanate and a binder resin to a release film and drying it. A laminated ceramic capacitor is manufactured by printing an electrode on a molded ceramic green sheet, peeling it from a release film, laminating the ceramic green sheet, pressing and cutting, firing, and applying an external electrode. Until now, when a ceramic green sheet was molded on the surface of the release layer of a polyester film, minute protrusions on the surface of the release layer affected the molded ceramic green sheet, and defects such as cissing and pinholes were likely to occur. There was a problem. Therefore, various methods for realizing a release layer surface having excellent flatness have been developed (for example, Patent Document 1).

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

As a method from the release layer side that smoothes the surface of the release layer and suppresses the load on the ceramic green sheet at the time of peeling, the release layer is formed by using an active energy ray-curable component for the release layer of the release film. Measures have been studied to suppress elastic deformation of the release layer at the time of peeling of the ceramic green sheet and reduce the peeling force by increasing the cross-linking density of the film and improving the elastic modulus (for example, Patent Documents 2 and 3). However, in this method, since the smoothness is too high, surface peeling occurs, the peeling force becomes heavy, and the green sheet may be cracked. Furthermore, when the ultra-thin ceramic green sheet is processed, if the smooth surface comes into contact with a smooth roll or rubber roll for controlling the tension of the coating equipment, the slipperiness of the roll and the smooth surface becomes insufficient and the tension control becomes unstable. There is a problem that the smoothness of the green sheet coated surface is lowered.

Therefore, a release film having an excellent balance between smoothness and uniform peelability has been reported by using a polyester film having an appropriate large protrusion that serves as a trigger (peeling start point) at the start of peeling (for example). , Patent Document 4). However, in the case of the filler kneaded into PET, there is a problem that the coarse protrusions due to the aggregation of the filler cannot be completely eliminated, which causes a defect of the product. In particular, in the ultrathin ceramic green sheet, the inorganic filler used as the ceramic material has a particle size of about 60 nm to 800 nm (Patent Documents 5 and 6), so that a film as described in Patent Document 4 is used. There was a problem that local holes were generated on the peeled surface.

Japanese Unexamined Patent Publication No. 2000-117899 International Publication No. 2013/145864 International Publication No. 2013/145856 International Publication No. 2014/203702 Japanese Unexamined Patent Publication No. 2016-127120 Japanese Unexamined Patent Publication No. 2017-081805

Therefore, as a result of diligent studies, the present inventors have caused the above-mentioned heavy peeling, deterioration of processing suitability, and occurrence of defect factors by continuously forming low protrusions having a constant shape on the surface of the release layer. It was determined that it could be suppressed at the same time. An object of the present invention is to provide a release film for molding a ceramic green sheet, which has excellent peelability and is less likely to cause damage such as pinhole defects and cracks during peeling to the ultrathin ceramic green sheet to be molded. Is.

That is, the present invention has the following configuration.
1. 1. A release film in which a release layer of 0.2 to 3.5 μm is laminated directly on at least one surface of the polyester film or via another layer, and the region surface roughness (Sa) of the surface of the release layer is high. A release film for manufacturing ceramic green sheets having a maximum mountain height (Rp) of 60 nm or less and 5 to 40 nm.
2. 2. The energy ray-curable compound (I) in which the release layer has an energy ray-curable compound (I) having three or more reactive groups in one molecule and the energy ray-curable compound (I) as a sea component, and the energy ray-curable compound (I) The release film for producing a ceramic green sheet according to the above first, wherein the coating film containing at least the resin (II) which is incompatible with and becomes an island component and the release component (III) is cured.
3. 3. The release film for producing a ceramic green sheet according to the first or second above, wherein the release layer does not substantially contain inorganic particles.
4. The polyester film is a laminated polyester film composed of at least two or more layers including a surface layer A and a surface layer B on the opposite side of the surface layer A, and a release layer is laminated on the surface layer A. The release film for producing a ceramic green sheet according to any one of the above 1 to 3, wherein the surface layer A does not substantially contain inorganic particles.
5. 4. The fourth item described above, wherein the surface layer B contains particles, the particles are silica particles and / or calcium carbonate particles, and the total content of the particles is 5000 to 15000 ppm with respect to the total mass of the surface layer B. Release film for manufacturing ceramic green sheets.
6. 3. The above-mentioned item 1 to 3 above, wherein the polyester film does not substantially contain inorganic particles, and a coating layer containing particles is laminated on the side where the release layer of the polyester film is not laminated. Release film for manufacturing ceramic green sheets.
7. A method for producing a ceramic green sheet by molding a ceramic green sheet using the release film for producing a ceramic green sheet according to any one of the above 1 to 6, wherein the molded ceramic green sheet is 0.2 μm to A method for producing a ceramic green sheet, which is characterized by having a thickness of 1.0 μm.

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

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

(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 a film-molded polyester usually generally used as the release film base material can be used. It is preferably a crystalline linear saturated polyester composed of an aromatic dibasic acid component and a diol component, for example, polyethylene terephthalate, polyethylene-2,6-naphthalate, polybutylene terephthalate, polytrimethylene terephthalate or these. A copolymer containing the constituent components of the resin as a main component is more preferable, and a polyester film formed from polyethylene terephthalate is particularly preferable. The repeating unit of ethylene terephthalate is preferably 90 mol% or more, more preferably 95 mol% or more, and other dicarboxylic acid components and diol components may be copolymerized in a small amount, but from the viewpoint of cost. , Preferably made only from terephthalic acid and ethylene glycol. Further, known additives such as antioxidants, light stabilizers, ultraviolet absorbers, crystallization agents and the like 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 its high bidirectional elastic modulus and the like.

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

The method for producing the polyester film in the present invention is not particularly limited, and a method generally used in the past can be used. For example, the polyester can be melted by an extruder, extruded into a film, cooled by a rotary cooling drum to obtain an unstretched film, and the unstretched film can be obtained by uniaxially or biaxially stretching. You can. The biaxially stretched film can be obtained by a method of sequentially biaxially stretching a longitudinally or laterally uniaxially stretched film in the lateral or longitudinal direction, or a method of simultaneously biaxially stretching an unstretched film in the longitudinal and horizontal directions. You can.

In the present invention, the stretching temperature at the time of stretching the polyester film is preferably set to be 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 thickness of the polyester film is preferably 12 to 50 μm, more preferably 12 to 38 μm, and even more preferably 15 μm to 31 μm. When the thickness of the film is 12 μm or more, it is preferable because there is no possibility of deformation due to heat during film production, the processing process of the release layer, and the molding of the ceramic green sheet. On the other hand, when the thickness of the film is 50 μm or less, the amount of film discarded after use does not become extremely large, which is preferable in reducing the environmental load, and moreover, the material per area of the release film used is small. Therefore, it is also preferable from an economic point of view.

The polyester film base material may be a single layer or a multilayer of two or more layers, but it may be a laminated polyester film having a surface layer A substantially free of inorganic particles on at least one side. 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 or the like on the opposite surface of the surface layer A which does not substantially contain inorganic particles. As for the laminated structure, if the layer to which the release layer is applied is the surface layer A, the layer on the opposite surface is the surface layer B, and the core layers other than these are the core layer C, the layer structure in the thickness direction is the release layer. A laminated structure such as / surface layer A / surface layer B or release layer / surface layer A / core layer C / surface layer B can be mentioned. As a matter 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 impart slipperiness for winding the film in a roll shape.

In the polyester film base material of the present invention, it is preferable that the surface layer A forming the surface to which the release layer is applied does not substantially contain inorganic particles. At this time, the region surface average roughness (Sa) of the surface layer A is preferably 7 nm or less. When Sa is 7 nm or less, pinholes and the like occur during molding of the ultra-thin ceramic green sheet to be laminated even if the release layer has a film thickness of 2.0 μm or less and is even thinner and 0.5 μm or less. Difficult and preferable. It can be said that the smaller the region surface average roughness (Sa) of the surface layer A is, the more preferable it is, but it may be 0.1 nm or more. However, when an anchor coat layer or the like described later is provided on the surface layer A, it is preferable that the coat layer does not substantially contain inorganic particles, and the region surface average roughness (Sa) after laminating the coat layer is within the above range. It is preferable to have. In the present invention, "substantially free of inorganic particles" is defined as 50 ppm or less when the inorganic element is quantified by Kay light X-ray analysis, preferably 10 ppm or less, and most preferably below the detection limit. The content is. This means that even if inorganic particles are not actively added to the film, contaminant components derived from foreign substances and stains attached to the raw material resin or the line or device in the film manufacturing process are peeled off and mixed into the film. This is because there are cases.

When the polyester film base material in the present invention is a laminated film, the surface layer B forming the opposite surface to the surface layer A to which the release layer is applied is a particle from the viewpoint of the slipperiness of the film and the ease with which air can escape. Is preferable, and silica particles and / or calcium carbonate particles are particularly preferable. The total amount of particles contained in the surface layer B is preferably 5000 to 15000 ppm. At this time, the region 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 amount of silica particles and / or calcium carbonate particles in the surface layer B is 5000 ppm or more and Sa is 1 nm or more, air can be uniformly released when the film is rolled up in a roll shape, and the rolled shape is good. The good flatness makes it suitable for manufacturing ultra-thin ceramic green sheets. Further, when the total amount of silica particles and / or calcium carbonate particles is 15,000 ppm or less and Sa is 40 nm or less, the lubricant is unlikely to aggregate and coarse protrusions cannot be formed. Therefore, the ultrathin ceramic green sheet is wound up after molding. Even in this case, it is preferable that the ceramic green sheet does not cause defects such as pinholes.

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. 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. Be done. Examples of the heat-resistant organic particles include crosslinked polyacrylic particles, crosslinked polystyrene particles, and benzoguanamine particles. When silica particles are used, porous colloidal silica is preferable, and when calcium carbonate particles are used, light calcium carbonate surface-treated with a polyacrylic acid-based polymer compound is preferable from the viewpoint of preventing the lubricant from falling off. ..

The average particle size of the particles added to the surface layer B is preferably 0.1 μm or more and 2.0 μm or less, and particularly preferably 0.5 μm or more and 1.0 μm or less. When the average particle size 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 size is 2.0 μm or less, pinholes due to coarse particles are not likely to occur on the surface of the release layer, which is preferable. The average particle size of the particles is measured by observing the particles in the cross section of the processed film with a scanning electron microscope, observing 100 particles, and using the average value as the average particle size. Can be done. The shape of the particles is not particularly limited as long as it satisfies the object of the present invention, and spherical particles and irregular 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 the pi (π), calculating the square root, and doubling it.

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

When the surface layer B does not contain particles, it is also preferable that a coat layer containing particles on the surface layer B has slipperiness. The means for providing the coating layer is not particularly limited, but it is preferable to provide the coating layer by a so-called in-line coating method in which the coating is applied during the film formation of the polyester film. Further, when a coat layer having a slipperiness 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 the inorganic particles are substantially contained. It may consist of a single-layer polyester film that does not contain the material.

The region surface average roughness (Sa) of the surface layer B is preferably 40 nm or less, more preferably 35 nm or less, and further preferably 30 nm or less. Further, when the surface layer B or the surface on the side where the release layer of the single-layer polyester film is not laminated is provided with the slipperiness by the coat layer (D), the surface Sa of the surface is measured by measuring the surface on which the coat layer is laminated. It is preferable that the surface layer B is in the same range as the region surface average roughness (Sa).

(Coat layer D)
It is preferable that at least a binder resin and particles are contained in the coat layer D on the surface of the polyester film on the side where 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 polyester resin, acrylic resin, urethane resin, polyvinyl resin (polyvinyl alcohol, etc.), polyalkylene glycol, polyalkyleneimine, and methyl cellulose. , Hydroxycellulose, polymers and the like. Among these, it is preferable to use polyester resin, acrylic resin, or urethane resin 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 for coat layer D)
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, carbodiimide-based, and aziridine. Further, in order to promote the cross-linking reaction, a catalyst or the like can be appropriately used as needed.

(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, 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 270 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 the RP) small to achieve both slipperiness and smoothness, and particularly preferably, small particles of 30 nm or more and 250 nm or less and average particles. Large particles with 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.

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

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

Further, from the viewpoint of economy, 50 to 90% by mass of film waste or a recycled raw material for PET bottles can be used for the layers other than the surface layer A (surface layer B or the core layer C described above). Even in this case, it is preferable that the type and amount of the lubricant contained in the surface layer B, the particle size, and the region surface average roughness (Sa) satisfy the above ranges.

In addition, a film before or after uniaxial stretching in the film forming process on the surface of the surface layer A and / or the surface layer B in order to improve the adhesion of the release layer to be applied later and prevent charging. A coat layer may be provided on the surface, or a corona treatment or the like may be applied. When a coat layer is also provided, the Sa of each layer is substituted by the measured value on the surface of the coat layer. Further, when these coat layers are provided on the surface of the surface layer A, it is preferable that they do not contain particles.

(Release layer)
The release layer of the present invention is incompatible with the energy ray-curable compound (I) having three or more reactive groups in one molecule and the energy ray-curable compound (I), and is phase-separated to form a sea-island structure. It is preferable that the coating film containing at least the resin (II) forming the above and the release component (III) is cured. The energy ray-curable compound (I) and the resin (II) are phase-separated to form a sea-island structure, which makes it easy to form irregularities of an appropriate height and does not generate coarse protrusions. No holes are generated. In addition, even a brittle ultra-thin ceramic green sheet can be peeled off without zipping because the flat surface portion is almost eliminated and the peeling occurs at points, so that damage such as cracks and deformation can be suppressed. ..

(Energy ray-curable compound (I) having 3 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 3 or more reactive groups in one molecule can be used. By having 3 or more reactive groups in one molecule, a release layer having a high elastic modulus can be obtained, deformation of the release layer at the time of peeling the green sheet can be suppressed, and heavy peeling can be suppressed. Further, since the solvent resistance of the release layer can be improved, erosion of the release layer by the solvent during slurry coating can be prevented, which is preferable. Further, the energy ray-curable compound having 3 or more reactive groups in one molecule is not particularly limited as to whether it reacts directly with energy rays or with an indirectly generated active species. The content of the energy ray-curable compound (I) in the solid content in the coating liquid for forming the release layer is preferably 60 to 98% by mass, preferably 75 to 97% by mass. By adding 60% by mass or more, the degree of cross-linking can be maintained and a high elastic modulus can be obtained.

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

The energy ray-curable compound having a (meth) acryloyl group is not limited to a monomer, an oligomer, and a polymer, and can be used. Further, it is preferable that at least one molecule contains a compound having 3 or more reactive groups, but 2 or more compounds such as a compound having 1 to 2 reactive groups in the molecule are mixed and used. You can also do it. By mixing these compounds having a small number of reactive groups, curling and the like can be suppressed.

Examples of the energy ray-curable monomer having 3 or more (meth) acryloyl groups in the molecule include isocyanuric acid triacrylate, glycerin tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, and tri. Methylolpropantri (meth) acrylate, ditrimethylolpropanetetra (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 and the like can be mentioned.

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, and 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 trimethylolpropaneformal (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxybutyl ( Meta) acrylate, hydroxypropyl (meth) acrylate, (meth) acrylic acid, dicyclopentenyloxyethyl (meth) acrylate, dicyclopentanyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, tetrahydro Flufuryl (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, pentamethylpiperidinyl (meth) acrylate, tetramethylpiperidinyl (meth) acrylate, 1,4-butanediol di (meth) acrylate, polyethylene glycol di Monomers such as (meth) acrylate, nonanediol di (meth) acrylate, bisphenol A di (meth) acrylate, neopentyl glycol di (meth) acrylate, cyclohexanediol di (meth) acrylate and their ethylene oxide modified products, propylene. Examples thereof include oxide-modified products and caprolactone-modified products.

Examples of energy ray-curable oligomers having 3 or more (meth) acryloyl groups in the molecule include urethane acrylates, polyester acrylates, polyether acrylates, epoxy acrylates, silicone-modified acrylates, and the like, which are generally commercially available. Can be used. For example, Arakawa Chemical Industry Co., Ltd. Beam Set (registered trademark) series, Shin Nakamura Chemical Industry Co., Ltd. NK Oligo series, Dicelle Ornex Co., Ltd. EBECRYL series, Osaka Organic Chemical Industry Co., Ltd. Viscoat series, Kyoei Co., Ltd. Chemical Company urethane acrylate series, Examples include the Unidic series manufactured by DIC.

Examples of energy ray-curable polymers having three or more (meth) acryloyl groups in the molecule include graft polymers obtained by grafting (meth) acryloyl groups on the polymers, and block polymers in which a polyfunctional acrylic monomer is added to the polymer ends. Can be mentioned. As the polymers as described above, acrylic resin, epoxy resin, polyester resin, polyorganosiloxane and the like can be used, and the present invention 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 both are dissolved or dispersed in the state of the coating agent, but after application, the solvent is dried. In the release layer formed through curing, they are incompatible with each other, and it is preferable to form a sea-island structure with the energy ray-curable compound (I) as a sea component and the resin (II) as an island component. As for (II), it can be used without particular limitation as long as the above requirements are satisfied. Two or more resins can be used at the same time. The content of the resin (II) in the coating liquid for forming a release layer is preferably 1 to 40% by mass, preferably 1 to 10% by mass. Sufficient unevenness can be formed by containing 1% by mass or more, and 40% by mass or less is preferable because the degree of cross-linking of the release layer is high and the temperature dependence at the time of peeling is low.

The resin (II) can be used without particular limitation as long as it is a solvent-soluble type such as polyester resin, acrylic resin, urethane resin, polyester urethane resin, polyimide resin, polyamideimide resin, and cellulose resin. 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. For example, the Byron (registered trademark) series manufactured by Toyobo Co., Ltd. and the Nichigo Polyester (registered trademark) series manufactured by Nippon Synthetic Chemical Industry Co., Ltd. can be mentioned.

The acrylic resin refers to an oligomer or polymer obtained by polymerizing an acrylic acid ester, and may be a homopolymer or a copolymer. Moreover, a commercially available product can be used. For example, the Acridic (registered trademark) series manufactured by DIC Corporation and the ARFON (registered trademark) series manufactured by Toagosei Corporation can be mentioned.

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

(Release component (III))
The release component (III) used in the present invention is not particularly limited as long as it is a material capable of exhibiting releasability with a green sheet such as polyorganosiloxane, fluorine compound, long-chain alkyl compound, and waxes. Further, a material having a functional group capable of reacting with and binding to the energy ray-curable compound (I) having a (meth) acryloyl group or the like is preferable. It is also possible to use a mixture of two or more kinds of materials. The content of the release component (III) in the solid content of the release layer forming coating liquid is preferably 0.05 to 10% by mass, more preferably 0.1 to 5% by mass. If it is added in an amount of 0.05% by mass or more, the peeling force can be lightened, and if it is 10% by mass or less, the transfer of the release component to a ceramic green sheet or the like is suppressed, which is preferable.

Examples of polyorganosiloxane include polydimethylsiloxane, polydiethylsiloxane, polyphenylsiloxane, and other siloxane-based compounds that are partially organically modified, block polymers that have polyorganosiloxane, and polymers that are grafted with polyorganosiloxane. Can be used. As commercially available products, for example, BYK (registered trademark) series manufactured by Big Chemie Japan, Modiper (registered trademark) series manufactured by NOF Corporation, and the like can be used.

The fluorine compound is not particularly limited, and commercially available ones can be used. For example, the Mega Fvck (registered trademark) series manufactured by DIC Corporation can be mentioned.

Examples of the long-chain alkyl compound include an acrylic polymer copolymerized with a long-chain alkyl acrylate, a graft polymer grafted with a long-chain alkyl, and a block polymer having a long-chain alkyl added to the end. Further, the product is not particularly limited, and a commercially available product can be used. For example, Tessfine (registered trademark) series manufactured by Hitachi Kasei Co., Ltd. and Piroyl (registered trademark) manufactured by Lion Specialty Chemicals Co., Ltd. can be mentioned.

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

The atmosphere when irradiating the active energy rays may be general air or a nitrogen gas atmosphere. In a nitrogen gas atmosphere, the radical reaction proceeds smoothly and the elastic modulus of the release layer can be improved by reducing the oxygen concentration, but if there is no practical problem even if it is irradiated in air, it is irradiated in air. It is preferable from an economical point of view.

(Photopolymerization initiator)
When a radical polymerization compound is used for 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, 2,4. -Diethylthioxanson, 1-hydroxycyclohexylphenylketone, benzyldiphenylsulfide, tetramethylthium monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, β-chloranthraquinone, (2,4,6-trimethyl) Benzyldiphenyl) phosphine oxide, 2-benzothiazole-N, N-diethyldithiocarbamate and the like can be mentioned. In particular, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] -phenyl} -2-methylpropan-1-one, which is said to have excellent surface curability, 1-Hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propane-1-one, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1 -On is preferable, and 2-hydroxy-2-methyl-1-phenyl-propane-1-one and 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one are particularly preferable. preferable. These may be used alone or in combination of two or more.

The amount of the photopolymerization initiator added is not particularly limited, but for example, it is preferably contained in an amount of about 0.1 to 20% by mass as the solid content in the coating liquid 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 or other particles that form protrusions from the viewpoint of pinhole generation.

An adhesion improver, an additive such as an antistatic agent, or the like 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 pretreatment such as anchor coating, corona treatment, plasma treatment, and atmospheric pressure plasma treatment on the surface of the polyester film 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, but preferably, the release layer after curing is preferably in the 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 polymer is good, and the elastic modulus of the release layer is improved, so that good peeling performance can be obtained, which is preferable. Further, when the thickness is 3.5 μm or less, curling is unlikely to occur even if the thickness of the release film is thin, and the ceramic green sheet is preferably formed and dried without causing poor running performance.

In the release film of the present invention, it is preferable that the surface of the release layer has appropriate irregularities. Therefore, the region surface average roughness (Sa) on the surface of the release layer is preferably 5 to 40 nm. Further, it is more preferable that the Sa is satisfied and the maximum protrusion height (Rp) on the surface of the release layer is 60 nm or less. Further, the region surface average roughness (Sa) is preferably 5 to 20 nm, more preferably 8.5 to 20 nm. At the same time, it is particularly preferable that the maximum protrusion height (Rp) is 50 nm or less. When the region surface roughness (Sa) is 5 nm or more, zipping is reduced when the ceramic green sheet is peeled off, and even an ultrathin layer green sheet can be easily peeled off without damage. Further, when the region surface roughness (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. When the above Sa is satisfied and the maximum protrusion height (Rp) of the release layer surface is 60 nm or less, the possibility of further pinhole defects is further reduced, which is preferable. The maximum protrusion height (Rp) is preferably small, but the maximum protrusion height (Rp) may be 5 nm or more in relation to adjusting the region surface average roughness (Sa) to 5 nm or more, and is 10 nm or more. It doesn't matter. In order to adjust the surface roughness (Sa) and maximum protrusion height (Rp) of the release layer as described above, various factors are related, but mainly the surface layer A of the polyester film. Alternatively, since the single-layer polyester film does not substantially contain inorganic particles, the surface roughness on which the release layer is laminated is small, and the release layer has three or more reactive groups in one molecule. The curable compound (I) and the energy ray-curable compound (I) are used as sea components, and the resin (II) which is incompatible with the energy ray-curable compound (I) and becomes an island component is contained 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 an appropriate range 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 on the surface of the release layer 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. When the coefficient of static friction is within the above range, the roll of the coating equipment slides well on the surface of the release layer and no excessive force is applied, so that damage to the surface of the release layer is reduced and damage to the green sheet is reduced. A good green sheet surface can be obtained.
Further, the coefficient of dynamic friction on 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 during the process.
Adjusting the range of the static friction coefficient and the dynamic friction coefficient of the release layer surface is related to the range of the surface roughness (Sa) and the maximum protrusion height (Rp) of the release layer, and the adjustment method thereof. Although there is no particular limitation, it can be preferably achieved mainly by adjusting the material combination and content ratio 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 releaseable compound is dissolved or dispersed is developed by coating or the like on one surface of a polyester film of a base material, and a solvent or the like is formed. Is removed by drying and then cured.

When the release layer of the present invention is applied onto the base film by solution coating, the drying temperature of solvent drying is preferably 50 ° C. or higher and 120 ° C. or lower, and 60 ° C. or higher and 100 ° C. or lower. More preferred. The drying time is preferably 30 seconds or less, more preferably 20 seconds or less. Further, after drying with a solvent, it is preferable to irradiate with active energy rays to proceed with the curing reaction. As the active energy beam used at this time, ultraviolet rays, electron beams, X-rays and the like can be used, but ultraviolet rays are preferable because they are easy to use. The amount of ultraviolet rays to be irradiated is preferably 30 to 300 mJ / cm ² in terms of the amount of light, and more preferably 30 to 200 mJ / cm ² . When the temperature is 30 mJ / cm ² or more, the composition is sufficiently cured, and when the temperature is 300 mJ / cm ² or less, the processing speed can be improved, so that a release film can be economically produced. preferable.

In the present invention, the surface tension of the coating liquid when the release layer is applied is not particularly limited, but is preferably 30 mN / m or less. By 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.

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.

In order to explain the present invention in detail, examples will be given below, but the present invention is not limited to these examples. The characteristic values used in the present invention were evaluated using the following method. Hereinafter, the weight average molecular weight may be simply referred to as Mw.

(1) Base film thickness Using a millitron (electronic micro-indicator), cut four 5 cm square samples from any four points of the film to be measured, measure each five points (20 points in total), and measure the average value. Was taken as the thickness.

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

(3) Region surface roughness (Sa), maximum protrusion 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 System Co., Ltd.). The region surface average roughness (Sa) was measured 5 times, and the maximum protrusion height (Rp) was measured 7 times, and the maximum value of 5 times excluding the maximum value and the minimum value was used.
(Measurement condition)
・ Measurement mode: WAVE mode ・ Objective lens: 50x ・ 0.5 × Tube lens (analysis conditions)
・ Surface correction: 4th order correction ・ Interpolation processing: Complete interpolation

(4) Evaluation of Pinholes in Ceramic Green Sheet The composition consisting of 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.
Toluene 76.3 parts by mass Ethanol 76.3 parts by mass Barium titanate (HPBT-1 manufactured by Fuji Titanium Industry Co., Ltd.) 35.0 parts by mass Polyvinyl butyral 3.5 parts by mass (Sekisui Chemical Co., Ltd. Eslek (registered trademark) BM-S )
DOP (Dioctyl phthalate) 1.8 parts by mass Next, apply an applicator to the release surface of the release film sample so that the dried ceramic green sheet is 0.8 μm, and dry at 90 ° C for 2 minutes. 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. The measurement was performed 5 times and the average value was adopted.
◯: Almost no pinholes occur (approximate: 2 or less pinholes per measurement area)
Δ: There are pinholes (approximate: 3 or more and 5 or less per measurement area) ×: There are many pinholes (approximate: 6 or more pinholes per measurement area)

(5) Evaluation of Damage to Ceramic Green Sheet The release film with ceramic green sheet prepared by the above method was cut into a width of 30 mm and a length of 80 mm to prepare a sample for measuring the peeling force. After static elimination using an electric removal machine (Keyence, SJ-F020), a peeling tester (VPA-3, Kyowa Interface Science Co., Ltd.) is used to remove the peeling angle at 30 degrees, the peeling temperature at 25 ° C, and the peeling speed at 10 m /. It peeled off in min. As for the direction of peeling, a double-sided adhesive tape (Nitto Denko Co., Ltd., No. 535A) is attached on the SUS plate attached to the peeling tester, and the ceramic green sheet side is bonded to the double-sided tape on the release film. Was fixed and peeled off by pulling the release film side. With respect to the surface of the ceramic green sheet that was in contact with the release film after peeling, 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 the average value measured 10 times was adopted. .. Visual judgment was made according to the following criteria.

◯: No damage during peeling (approximate: no cracks or deformation)
Δ: There is slight damage during peeling (approximate: 1 or more and 3 or less cracks and deformations per measurement area)
×: Severe damage during peeling (approximate: 4 or more cracks and deformations)

The peeling angle in this evaluation method refers to the angle in the direction in which the release film is pulled with respect to the evaluation sample shaft fixed to the peeling tester. The peeling temperature is the temperature at which the release film fixed by using the heater type stage system attached to the device is heated. After confirming that the measurement sample has reached the corresponding temperature using a handy type thermometer (manufactured by Anritsu Meter Co., Ltd., HD-1400E), peeling is performed.

(6) Static friction coefficient, dynamic friction coefficient When a Tencilon universal testing machine (manufactured by A & D Co., Ltd., RTG-1210) is used to overlap the surface of the release layer of the film so that the SUS plate is in contact with each other. The static friction coefficient (μs) and dynamic friction coefficient (μd) of the contact surface were measured under the following conditions in accordance with JIS K-7125.

Specimen: Width 50 mm x Length 60 mm
Load: 4.4 kg
Test speed: 200 mm / min
Friction material: SUS plate

(Preparation of polyethylene terephthalate pellets (PET (1)))
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 product in the first esterification reaction can is continuously taken out of the system and supplied to the second esterification reaction can, and distilled off from the first esterification reaction can 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 acetate 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 products of the second esterification reaction can are 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 an 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 (1)). .. The lubricant content in the PET chip was 0.6% by mass.

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

(Manufacturing 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 stainless steel fibers having a 95% cut diameter of 15 μm and a 95% cut diameter are obtained. Two-stage filtration of a filter obtained by sintering 15 μm stainless steel particles is performed, and the PET (1) is combined with the surface layer B (extrusion type surface side layer) and the PET (2) is surfaced. It is laminated so as to be layer A (separation surface side layer), extruded (casting) into a sheet at a speed of 45 m / min, and electrostatically adhered and cooled on a casting drum at 30 ° C. by the electrostatic adhesion method. An unstretched polyethylene terephthalate sheet having an intrinsic viscosity of 0.59 dl / g was obtained. The layer ratio was adjusted so that PET (1) / (2) = 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 X1 having a thickness of 31 μm. The Sa of the surface layer A of the obtained film X1 was 2 nm, and the Sa of the surface layer B was 29 nm.

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

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

(Example 1)
A coating liquid 1 having the following composition is applied onto the surface layer A of the laminated film X1 using reverse gravure so that the release layer thickness after drying is 2.5 μm, dried at 90 ° C. for 30 seconds, and then subjected to high pressure. A release film for producing an ultrathin ceramic green sheet was obtained by irradiating ultraviolet rays at 200 mJ / cm ² using a mercury lamp. For the obtained release film, the release layer thickness, region surface roughness Sa, maximum protrusion height Rp, pinhole evaluation of the ceramic green sheet, damage evaluation to the ceramic green sheet, static friction coefficient, and dynamic friction coefficient were evaluated. It was.

(Coating liquid 1)
Compound (I) 100.00 parts by mass
(Dipentaerythritol hexaacrylate, A-DPH manufactured by Shin-Nakamura Chemical Industry Co., Ltd., solid content concentration 100%)
Resin (II) Polyester resin 9.47 parts by mass (Byron (registered trademark) RV280 manufactured by Toyobo Co., Ltd., solid content concentration 100% by mass)
Release agent (III) 1.26 parts by mass (modified polydimethylsiloxane having an acryloyl group, BYK-UV3505, manufactured by Big Chemie Japan, solid content concentration 40% by mass)
Photopolymerization initiator 5.25 parts by mass (OMNIRAD (registered trademark) 907, manufactured by IGM Japan GK, solid content concentration 100% by mass)
Diluting solvent (MEK / toluene = 1/1) 459.79 parts by mass

(Example 2)
The resin (II) was changed to a polyester urethane resin (Byron (registered trademark) UR1400 manufactured by Toyobo Co., Ltd., solid content concentration 30% by mass), and the following coating liquid 2 was used. The solid content concentration of the coating liquid 2 was reduced as compared with the coating liquid 1 of Example 1. The coating was applied so that the release layer film thickness 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 release layer was coated so that the film thickness of the release layer after drying was 1.5 μm. The obtained release film was evaluated for the release layer thickness, region surface roughness Sa, maximum protrusion height Rp, pinhole evaluation of the ceramic green sheet, damage evaluation to the ceramic green sheet, static friction coefficient, and dynamic friction coefficient. It was.

(Coating liquid 2)
Compound (I) 100.00 parts by mass (dipentaerythritol hexaacrylate, A-DPH manufactured by Shin-Nakamura Chemical Industry Co., Ltd., solid content concentration 100%)
Resin (II) Polyester urethane resin 31.50 parts by mass (Toyobo Co., Ltd. Byron (registered trademark) UR1400, solid content concentration 30% by mass)
Release agent (III) 0.42 parts by mass (modified polydimethylsiloxane having an acryloyl group, BYK-UV3505, manufactured by Big Chemie Japan, solid content concentration 40% by mass)
Photopolymerization initiator 5.25 parts by mass (OMNIRAD (registered trademark) 907, manufactured by IGM Japan GK, solid content concentration 100% by mass)
Diluting solvent (MEK / toluene = 1/1) 955.42 parts by mass

(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. The coating was applied so that the release layer film thickness 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 release layer was coated so that the film thickness of the release layer after drying was 1.8 μm. The obtained release film was evaluated for the release layer thickness, region surface roughness Sa, maximum protrusion height Rp, pinhole evaluation of the ceramic green sheet, damage evaluation to the ceramic green sheet, static friction coefficient, and dynamic friction coefficient. It was.

(Coating liquid 3)
Compound (I) 100.00 parts by mass (dipentaerythritol hexaacrylate, A-DPH manufactured by Shin-Nakamura Chemical Industry Co., Ltd., solid content concentration 100%)
Resin (II) Polyester urethane resin 31.50 parts by mass (Toyobo Co., Ltd. Byron (registered trademark) UR1400, solid content concentration 30% by mass)
Release agent (III) 1.26 parts by mass (modified polydimethylsiloxane having an acryloyl group, BYK-UV3505, manufactured by Big Chemie Japan, solid content concentration 40% by mass)
Photopolymerization initiator 5.25 parts by mass (OMNIRAD (registered trademark) 907, manufactured by IGM Japan GK, solid content 100% by mass)
Diluting solvent (MEK / toluene = 1/1) 982.98 parts by mass

(Example 4)
The coating liquid 3 used in Example 3 was applied onto 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. The obtained release film was evaluated for the release layer thickness, region surface roughness Sa, maximum protrusion height Rp, pinhole evaluation of the ceramic green sheet, damage evaluation to the ceramic green sheet, static friction coefficient, and dynamic friction coefficient. It was.

(Example 5)
The coating liquid 3 used in Example 3 was applied onto 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. The obtained release film was evaluated for the release layer thickness, region surface roughness Sa, maximum protrusion height Rp, pinhole evaluation of the ceramic green sheet, damage evaluation to the ceramic green sheet, static friction coefficient, and dynamic friction coefficient. It was.

(Comparative Example 1)
Compared to Example 1, the resin (II) is not contained, and the release agent (III) is contained in a polyether-modified polydimethylsiloxane having an acryloyl group (BYK UV-3500, 100% solid content concentration manufactured by Big Chemy Japan). The following coating liquid 4 was used, in which the addition amount was increased and the diluting 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 the release layer was coated so that the film thickness of the release layer after drying was 1.0 μm. The obtained release film was evaluated for the release layer thickness, region surface roughness Sa, maximum protrusion height Rp, pinhole evaluation of the ceramic green sheet, damage evaluation to the ceramic green sheet, static friction coefficient, and dynamic friction coefficient. It was.

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

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

Claims (9)

A release film in which a release layer of 0.2 to 3.5 μm is laminated directly on at least one surface of the polyester film or via another layer, and the region surface roughness (Sa) of the surface of the release layer is high. 5~40nm, maximum peak height (Rp) is Ri der below 60nm,
The energy ray-curable compound (I) in which the release layer contains an energy ray-curable compound (I) having three or more reactive groups in one molecule and the energy ray-curable compound (I) as a sea component, and the energy ray-curable compound ( I). ) And a resin (II) that is incompatible with the island component and a release film containing at least the release component (III) is cured to form a release film for manufacturing a ceramic green sheet. Compound (I) is an energy ray-curable monomer having three or more (meth) acryloyl groups in the molecule, the resin (II) is a polyester resin, acrylic resin, urethane resin, poly ester urethane resin, polyimide resin, it is at least one selected from the group consisting of polyamide-imide resin and cellulosic resins, release film for producing a ceramic green sheet according to claim 1. The release film for producing a ceramic green sheet according to claim 1 or 2, wherein the release layer does not substantially contain inorganic particles. The polyester film is a laminated polyester film composed of at least two or more layers including a surface layer A and a surface layer B on the opposite side of the surface layer A, and 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 does not substantially contain inorganic particles. The fourth aspect of claim 4, wherein the surface layer B contains particles, the particles are silica particles and / or calcium carbonate particles, and the total content of the particles is 5000 to 15000 ppm with respect to 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 the side where the release layer of the polyester film is not laminated. Release film for green sheet manufacturing. The release layer forming coating liquid for forming the release layer further contains a photopolymerization initiator.
The content of the energy ray-curable compound (I) in the solid content of the release layer forming coating liquid is 60. ~ 98% by mass,
The content of the resin (II) in the solid content in the coating liquid for forming the release layer is 1 to 40% by mass.
The content of the release component (III) in the solid content of the release layer forming coating solution is 0.05 to 10% by mass. The total of the components (I), (II), (III) and the photopolymerization initiator is 100% by mass.
The release film for producing a ceramic green sheet according to any one of claims 1 to 6. The energy ray-curable compound (I) has three or more (meth) acryloyl groups in the molecule. Energy ray-curable monomer
Energy ray-curable monomers having 3 or more (meth) acryloyl groups in the molecule
Isocyanuric acid triacrylate, glycerin tri (meth) acrylate, pentaeryth Ritoltri (meth) acrylate, pentaerythritol tetra (meth) acrylate , Trimethylolpropane Tri (meth) acrylate, Ditrimethylolpropane tetra (Meta) acrylate, dipentaerythritol tri (meth) acrylate, dipentae Lithritol tetra (meth) acrylate, dipentaerythritol penta (meth) ac Less selected from relate and dipentaerythritol hexa (meth) acrylate Both include one
The release film for manufacturing a ceramic green sheet according to any one of claims 1 to 7. A method for producing a ceramic green sheet using the release film for producing a ceramic green sheet according to any one of claims 1 to 8, wherein the molded ceramic green sheet is 0.2 μm to 1 A method for producing a ceramic green sheet, which is characterized by having a thickness of 0.0 μm.