JP7017168B2 - 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, to suppress the occurrence of process defects due to pinholes, uneven thickness and poor peeling during production of an ultra-thin layer ceramic green sheet. It relates to a release film for manufacturing an ultra-thin ceramic green sheet that can be manufactured.

Conventionally, a release film having a polyester film as a base material and a release layer laminated on the polyester film 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, as the size and capacity of multilayer ceramic capacitors have increased, the thickness of ceramic green sheets has also tended to decrease. 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 and pressing a ceramic green sheet, cutting it, firing it, and applying an external electrode. Until now, when a ceramic green sheet is molded on the surface of the release layer of a polyester film, minute protrusions on the surface of the release layer affect the molded ceramic green sheet, and defects such as repellent and pinholes are 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 is preferable to reduce the load applied to the ceramic green sheet as much as possible when peeling the ceramic green sheet from the release film so as not to damage the ceramic green sheet.

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-curing component for the release layer of the release film. Measures have been studied for suppressing elastic deformation of the release layer at the time of peeling of the ceramic green sheet and reducing the peeling force by increasing the cross-linking density 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 was a problem that the smoothness of the green sheet coated surface was 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 ultra-thin layer 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. 2013/145865 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 workability and generation 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 mold 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 mold release film for manufacturing ceramic green sheets having a maximum mountain height (Rp) of 60 nm or less and 5 to 40 nm.
The static friction coefficient of the surface of the release layer of the release layer film is 0.05 or more and 2.00 or less, and the dynamic friction coefficient is 1.00 or less.
2. 2. 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). The release film for producing a ceramic green sheet according to the first item above, 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. The above-mentioned first to third, 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. In one embodiment, the intrinsic viscosity of the polyethylene terephthalate film is 0.50 to 0.70 dl / g.
8. A method for manufacturing a ceramic green sheet by molding a ceramic green sheet using the release film for manufacturing a ceramic green sheet according to any one of the above 1 to 6, wherein the molded ceramic green sheet is 0.2 μm or more. A method for manufacturing 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 processability is excellent, and the release layer has large protrusions as compared with the conventional release film for producing a ceramic green sheet. Therefore, it has become possible to provide a mold release film for manufacturing 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 ultrathin 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. 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. Preferably, it is 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 a 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. I can. The biaxially stretched film can be obtained by a method of sequentially biaxially stretching a uniaxially stretched film in a vertical or horizontal direction in a horizontal or vertical direction, or a method of simultaneously biaxially stretching an unstretched film in the vertical and horizontal directions. I 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 terms of 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 may be a laminated polyester film having a surface layer A substantially free of inorganic particles on at least one side thereof. 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 on the side to which the release layer is applied is the surface layer A, the layer on the opposite surface thereof 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 mold 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 into a roll.

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 a thin film of 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, which will be described later, is provided on the surface layer A, it is preferable that the coat layer does not contain substantially 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 the optical X-ray analysis, preferably 10 ppm or less, and most preferably the detection limit or less. Content. This means that even if inorganic particles are not actively added to the film, contamination components derived from foreign substances and stains attached to raw material resins or lines and devices 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. It is preferable to contain silica particles and / or calcium carbonate particles in particular. 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 into a roll shape, and the rolled shape is good. The good flatness makes it suitable for manufacturing ultra-thin ceramic green sheets. 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. Inactive inorganic particles and / or heat-resistant organic particles can be used in addition to silica and / or calcium carbonate, 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 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 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 amorphous non-spherical particles can be used. The particle size of the amorphous particles can be calculated as the equivalent circle diameter. The equivalent circle diameter is a value obtained by dividing the observed particle area by 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 to provide slipperiness with a coat layer containing particles on the surface layer B. The means for providing the coat layer is not particularly limited, but it is preferable to provide the coat layer by a so-called in-line coat method in which the coat is applied during the film formation of the polyester film. Further, in the case of providing a coat layer having slipperiness on the surface on the side where the release layer of the polyester film 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 be made 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 of the single-layer polyester film on the side where the release layer is not laminated is provided with 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, polyalkylene imine, and methyl cellulose. , Hydroxycellulose, polymers and the like. Among these, it is preferable to use a polyester resin, an acrylic resin, or a urethane resin from the viewpoint of particle retention and adhesion. Further, the polyester resin is particularly preferable in consideration of the familiarity with the 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, etc. Barium Sulfate, Carbon Black, Zinc Oxide, Zinc Sulfate, Zinc Carbonate, Zinc Oxide, Titanium Dioxide, Satin White, Aluminum Silate, Soil Kaiso, Calcium Silica, 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 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. When the average particle size of the particles is 10 nm or more, it is difficult to aggregate and slipperiness can be ensured, which is preferable.

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 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. When 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 the entire layer 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 economic efficiency, 50 to 90% by mass of film scraps or recycled raw materials for PET bottles can be used for the layers other than the surface layer A (surface layer B or the above-mentioned core layer C). 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.

Further, 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 resin (II) 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 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 of 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 of the release layer forming coating liquid 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, glycerintri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, and tri. Methylol propanetri (meth) acrylate, ditrimethylol propanetetra (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate. ) 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 Full frill (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, Beam Set (registered trademark) series manufactured by Arakawa Chemical Industry Co., Ltd., NK Oligo series manufactured by Shin-Nakamura Chemical Co., Ltd., EBECRYL series manufactured by Dicel Ornex, Viscoat series manufactured by Osaka Organic Chemical Industry Co., Ltd., Urethane acrylate series manufactured by Kyoei Co., Ltd., 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 polymers, block polymers in which a polyfunctional acrylic monomer is added to the polymer ends, and the like. Can be mentioned. As the polymers as described above, acrylic resin, epoxy resin, polyester resin, polyorganosiloxane and the like can be used, and the polymer 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 (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. When it is contained in an amount of 1% by mass or more, sufficient unevenness can be formed, and when it is 40% by mass or less, the degree of cross-linking of the release layer is high and the temperature dependence at the time of peeling is low, which is preferable.

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, polyamide-imide 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. may 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, the ARFON (registered trademark) series manufactured by Toagosei Corporation, and the like can be mentioned.

Examples of the polyester urethane resin include 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 that can exhibit 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 the energy ray-curable compound (I) having a (meth) acryloyl group or the like and binding to these materials is preferable. It is also possible to mix and use 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 can be suppressed, which is preferable.

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

The fluorine compound is not particularly limited, and a commercially available compound can be used. For example, DIC's Megafuck (registered trademark) series and the like 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, the Tessfine (registered trademark) series manufactured by Hitachi Kasei Co., Ltd. and the Piroyl (registered trademark) manufactured by Lion Specialty Chemicals Co., Ltd. can be mentioned.

Examples of the active energy beam include infrared rays, visible rays, ultraviolet rays, electromagnetic waves such as 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 the air, it is irradiated in the air. It is preferable from an economic point of view.

(Photopolymerization initiator)
When a radical polymerization-based 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 preferred, especially 2-hydroxy-2-methyl-1-phenyl-propane-1-one, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one. 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 the like 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 substrate, 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 it is 3.5 μm or less, it is preferable that curl does not easily occur even if the thickness of the release film becomes thin, and the running performance is not deteriorated in the process of molding and drying the ceramic green sheet.

The release film of the present invention preferably has an appropriate unevenness on the surface of the release layer. Therefore, it is preferable that the region surface average roughness (Sa) of the release layer surface is 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 causing 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. Various factors are involved in adjusting the range of the surface roughness (Sa) and the maximum protrusion height (Rp) of the release layer as described above, 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 excessive force is not applied, so that damage to the surface of the release layer is reduced and damage to the green sheet is reduced. And a good green sheet surface is 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 during the process.
Adjusting to 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 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 releaseable compound is dissolved or dispersed is developed by coating on one surface of a polyester film as a base material, and a solvent or the like is used. 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 for 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 light amount, and more preferably 30 to 200 mJ / cm ² . When it is 30 mJ / cm ² or more, the curing of the composition progresses sufficiently, and when it is 300 mJ / cm ² or less, the speed at the time of processing 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 coat 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 an optical interferometry 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 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 can be seen, 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 measured 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 the 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 prepare a sample for measuring the peeling force. After static elimination using an electric eliminator (Keyence, SJ-F020), a peeling tester (VPA-3, Kyowa Interface Science) is used to peel off at an angle of 30 degrees, a peeling temperature of 25 ° C, and a peeling speed of 10 m /. It peeled off at 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 on 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 cracks and deformation per measurement area, 3 or less)
×: Severe damage during peeling (approximate: 4 or more cracks and deformation)

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. Using a handy type thermometer (manufactured by Anritsu Keiki Co., Ltd., HD-1400E), peeling is performed after confirming that the measurement sample has reached the corresponding temperature.

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

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) is 2 tons / hour, EG (ethylene glycol) is 2 mol per 1 mol of TPA, antimony trioxide is made up to 160 ppm of Sb atoms with respect to the PET produced, and these slurrys are esterified. It was continuously supplied to the first esterification reaction can of the chemical reaction apparatus, and reacted at normal pressure with 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 magnesium acetate tetrahydrate in an amount of 65 ppm of Mg atoms with respect to the produced PET and 40 ppm of P atoms with respect to the produced PET. An EG solution containing an amount of TMPA (trimethyl phosphate) was added, and the reaction was carried out at normal pressure for an average residence time of 1 hour and 260 ° C. Next, the reaction product of the second esterification reaction can was continuously taken out of the system and supplied to the third esterification reaction can, and 39 MPa (400 kg / cm ² ) was used using a high-pressure disperser (manufactured by Nippon Seiki Co., Ltd.). 0.2 mass% of porous colloidal silica having an average particle diameter of 0.9 μm and 1 mass% of ammonium salt of polyacrylic acid attached per calcium carbonate after dispersion treatment with an average number of treatments of 5 passes under the pressure of 0.4% by mass of synthetic calcium carbonate having a diameter of 0.6 μm was added as an EG slurry of 10% each, and the reaction was carried out at normal pressure for an average residence time of 0.5 hours and 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 perform polycondensation, and a stainless steel fiber having a 95% cut diameter of 20 μm was sintered. After filtering with a filter, it was subjected to ultracondensation, extruded into water, cooled, and then cut into chips to obtain PET chips with 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 an 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 were melted at 285 ° C, melted at 290 ° C by a separate melt extruder extruder, and a filter obtained by sintering stainless steel fibers having a 95% cut diameter of 15 μm and a filter having a 95% cut diameter. 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 (anti-separable 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 laterally 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 high pressure is applied. 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. rice field.

(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. rice field.

(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 (Byron (registered trademark) UR1400 manufactured by Toyobo Co., Ltd., 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) 975.42 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. rice field.

(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 (Byron (registered trademark) UR1400 manufactured by Toyobo Co., Ltd., 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. rice field.

(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. rice field.

(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, solid content concentration 100% manufactured by Big Chemy Japan). The following coating liquid 4 in which the addition amount was increased and the diluting solvent was changed was used. 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. rice field.

(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 (7)

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. 5-40 nm, maximum mountain height (Rp) is 60 nm or less,
The static friction coefficient of the release layer surface of the release layer film is 0.05 or more and 2.00 or less, and the dynamic friction coefficient is 1.00 or less .
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 sea components, and the energy ray-curable compound (I). ) And a coating film containing at least the release component (III) and the resin (II) which is incompatible with the island component, and is a release film for manufacturing a ceramic green sheet. The release film for producing a ceramic green sheet according to claim 1, 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 claim 1 or 2 , wherein the surface layer A does not substantially contain inorganic particles. The third aspect of claim 3 , 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 green sheet production according to claim 1 or 2 , 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. The release film for producing a ceramic green sheet according to any one of claims 1 to 5 , wherein the polyethylene terephthalate film has an intrinsic viscosity of 0.50 to 0.70 dl / g. A method for manufacturing a ceramic green sheet by molding a ceramic green sheet using the release film for manufacturing a ceramic green sheet according to any one of claims 1 to 6 , wherein the molded ceramic green sheet is 0.2 μm to 1 A method for manufacturing a ceramic green sheet, which is characterized by having a thickness of 0.0 μm.