WO2019131449A1 - Mold release film for production of ceramic green sheet - Google Patents

Abstract

[Problem] To provide a mold release film for molding of a ceramic green sheet, which has excellent releasability and is not likely to cause pin hole defects and damage such as cracks during releasing on an ultrathin ceramic green sheet that is molded with use of the mold release film. [Solution] A mold release film for the production of a ceramic green sheet, which is obtained by superposing a mold release layer having a thickness of 0.2-3.5 μm on at least one surface of a polyester film directly or with another layer being interposed therebetween, and which is configured such that the surface of the mold release layer has a local surface roughness (Sa) of 5-40 nm and a maximum profile peak height (Rp) of 60 nm or less.

Description

Release film for ceramic green sheet production

The present invention relates to a release film for producing an ultra-thin layer ceramic green sheet, and more specifically, a production method for suppressing the occurrence of process defects due to pinholes and uneven thickness and peeling defects at the time of producing an ultra-thin layer ceramic green sheet The present invention relates to a release film for producing an ultra-thin layer ceramic green sheet that can be produced.

Conventionally, a release film having a polyester film as a base material and a release layer laminated thereon is used for forming a ceramic green sheet such as a multilayer ceramic capacitor (hereinafter referred to as MLCC), a ceramic substrate or the like. In recent years, the thickness of ceramic green sheets tends to be thinner along with the miniaturization and the increase in capacity of multilayer ceramic capacitors. The ceramic green sheet is molded by coating and drying a slurry containing a ceramic component such as barium titanate and a binder resin on a release film. After printing an electrode on a molded ceramic green sheet and peeling it from a release film, a laminated ceramic capacitor is manufactured by laminating, pressing and cutting the ceramic green sheet, and firing and applying an external electrode. So far, when molding a ceramic green sheet on the surface of the release layer of polyester film, minute projections on the surface of the release layer affect the formed ceramic green sheet, and defects such as repelling and pinholes are likely to occur. There was a problem. Therefore, various methods have been developed for realizing a release layer surface having excellent flatness (for example, Patent Document 1).

However, in recent years, the thickness of ceramic green sheets has been further reduced, and ceramic green sheets having a thickness of 1.0 μm or less, more specifically 0.2 μm to 1.0 μm, have been required. Therefore, higher smoothness is required on the surface of the release layer. In addition, since the strength of the ceramic green sheet decreases as the thickness of the ceramic green sheet decreases, not only the surface of the release layer is smoothed, but also the peel strength when peeling the ceramic green sheet 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, and to prevent the ceramic green sheet from being damaged.

As a method from the mold release layer side to suppress the load on the ceramic green sheet at the time of smoothing and peeling of the mold release layer surface, the mold release layer is used by using an active energy ray curing component in the mold release layer By increasing the crosslink density of the above and improving the elastic modulus, measures have been studied for suppressing the elastic deformation of the release layer at the time of peeling of the ceramic green sheet and reducing the peeling force (for example, Patent Documents 2 and 3). However, in this method, the surface is exfoliated because the smoothness is too high, the exfoliation force is increased, and the green sheet may be cracked. Furthermore, when the ultra-thin ceramic green sheet is processed, if the smooth surface is in contact with the smooth roll or rubber roll for controlling the tension of the coating equipment, the slippage between the roll and the smooth surface is insufficient and tension control becomes unstable. There was a problem that the smoothness of the coated surface of the green sheet was reduced.

Therefore, a mold release film excellent in balance between smoothness and uniform peelability has been reported by using a polyester film having a suitable large protrusion serving as a trigger at the start of peeling (peeling start point) (for example, for example , Patent Document 4). However, in the case of the filler kneaded in PET, the coarse projections due to filler aggregation can not be completely eliminated, and there is a problem that causes defects in the product. In particular, in the ultra-thin ceramic green sheet, since the inorganic filler used as the ceramic material has a particle size of about 60 nm to 800 nm (Patent Documents 5 and 6), when a film as described in Patent Document 4 is used, There was a problem that a local hole was generated at the peeling surface.

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

Therefore, as a result of intensive investigations, the present inventors continuously form a low protrusion having a constant shape on the surface of the mold release layer, thereby causing the above-described heavy peeling, the deterioration of processing suitability, and the generation of a defect factor. At the same time, I determined that I could suppress it. And the object of the present invention is to provide a release film for forming a ceramic green sheet which is excellent in releasability and hardly causes damage such as a pinhole defect or a crack at the time of exfoliation to an extremely thin ceramic green sheet to be formed. It is.

That is, the present invention has the following constitution.
1. A release film in which a release layer of 0.2 to 3.5 μm is laminated on at least one surface of a polyester film directly or through another layer, and the area surface roughness (Sa) of the release layer surface is A release film for producing a ceramic green sheet, having a maximum peak height (Rp) of 60 nm or less and 5 to 40 nm.
2. An energy ray-curable compound (I), wherein the releasing layer has three or more reactive groups in one molecule, and the energy ray-curable compound (I) as a sea component, the energy ray-curable compound (I) The release film for producing a ceramic green sheet according to the first above, wherein a coating film containing at least a resin (II) which is incompatible with the resin and which becomes an island component and a releasing component (III) is cured.
3. The mold release film for producing a ceramic green sheet according to the first or second form, wherein the mold release layer is substantially free of inorganic particles.
4. The polyester film is a laminated polyester film comprising at least a surface layer A and two or more layers including a surface layer B opposite to the surface layer A, 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 first to the third, wherein the surface layer A contains substantially no inorganic particles.
5. The surface layer B contains particles, the particles are silica particles and / or calcium carbonate particles, and the total content of particles is 5000 to 15000 ppm with respect to the total mass of the surface layer B. Release film for ceramic green sheet production.
6. The polyester film according to any one of the above 1 to 3, wherein the polyester film is substantially free of inorganic particles and a coating layer containing the particles is laminated on the side of the polyester film on which the release layer is not laminated. Release film for ceramic green sheet production.
7. A method for producing a ceramic green sheet, wherein the ceramic green sheet is formed by using the release film for producing a ceramic green sheet according to any one of the first to sixth aspects, wherein the formed ceramic green sheet has a thickness of 0.2 μm to A method of producing a ceramic green sheet characterized by having a thickness of 1.0 μm.

According to the release film for producing a ceramic green sheet of the present invention, compared to the conventional release film for producing a ceramic green sheet, the peeling force is not too heavy, the processability is excellent, and the large protrusion is formed on the release layer. Since there is no film, it has become possible to provide a release film for producing a ceramic green sheet capable of reducing defects such as pinholes in an ultrathin 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 on at least one side of the polyester film directly or through another layer, and the surface roughness (Sa of the release layer surface) (Sa And the maximum peak height (Rp) is preferably 60 nm or less. And, 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 a sea-island structure by phase separation. A mold release film for producing a ceramic green sheet, in which a coating film containing at least a resin (II) forming the resin and a mold release component (III) is cured is a preferred embodiment.

(Polyester film)
The polyester constituting the polyester film used as the substrate in the release film of the present invention is not particularly limited, and polyester film generally used as a release film substrate can be film-molded, but 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 Further preferred is a copolymer having as a main component a component of the resin of (1), and particularly preferred is a polyester film formed of polyethylene terephthalate. In polyethylene terephthalate, the repeating unit of ethylene terephthalate is preferably 90 mol% or more, more preferably 95 mol% or more, and small amounts of other dicarboxylic acid components and diol components may be copolymerized, but from the viewpoint of cost And those produced solely from terephthalic acid and ethylene glycol. In addition, known additives, for example, an antioxidant, a light stabilizer, an ultraviolet light absorber, a crystallizing agent and the like may be added within a range not to inhibit the effect of the film of the present invention. The polyester film is preferably a polyester film because of the height of the elastic modulus in both directions 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, breakage is less likely to occur in the stretching step, which is preferable. On the contrary, when it is 0.70 dl / g or less, it is preferable because the cutting property when cutting into a predetermined product width is good and dimensional defects do not occur. In addition, it is preferable that the raw material be sufficiently vacuum dried.

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

In the present invention, the stretching temperature at the time of stretching the polyester film is preferably at least 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 longitudinal and transverse directions.

The polyester film preferably has a thickness of 12 to 50 μm, more preferably 12 to 38 μm, and still more preferably 15 to 31 μm. If the thickness of the film is 12 μm or more, it is preferable because there is no risk of deformation due to heat at the time of film production, processing step of the release layer, and molding of the ceramic green sheet. On the other hand, if the thickness of the film is 50 μm or less, the amount of film discarded after use is not extremely large, which is preferable in reducing the environmental impact, and furthermore, the material per area of the release film used is small. It is also preferable from the economic point of view.

The polyester film substrate may be a single layer or a multilayer of two or more layers, but it is 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 and the like on the opposite surface of the surface layer A substantially free of inorganic particles. In the laminated structure, assuming that 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 configuration in the thickness direction is the release layer. / Layer structure of surface layer A / surface layer B, or release layer / surface layer A / core layer C / surface layer B, etc. may be mentioned. Naturally, the core layer C may have a plurality of layer configurations. The surface layer B can also contain no 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 substrate in 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 area average surface roughness (Sa) of the surface layer A is preferably 7 nm or less. If Sa is 7 nm or less, even if the thickness of the release layer is 2.0 μm or less, and even a thin film such as 0.5 μm or less, pinholes or the like occur during molding of the ultra-thin ceramic green sheet to be laminated Hard and preferred. The area average surface roughness (Sa) of the surface layer A is preferably as small as possible, but may be 0.1 nm or more. However, when providing the below-mentioned anchor coat layer etc. on surface layer A, it is preferable that an inorganic particle is not included in a coat layer substantially, and the field surface average roughness (Sa) after coat layer lamination is within the above-mentioned range. Is preferred. In the present invention, "substantially free of inorganic particles" is defined as 50 ppm or less when the inorganic element is quantified by fluorescent X-ray analysis, preferably 10 ppm or less, and most preferably below the detection limit. Content. This is because, even if the inorganic particles are not positively added to the film, contamination components derived from extraneous foreign matter, stains attached to the lines and devices in the manufacturing process of the raw material resin or the film are peeled off and mixed in the film. It is because there is a case.

In the case where the polyester film substrate in the present invention is a laminated film, the surface layer B forming the surface opposite to the surface layer A to which the release layer is applied is in the form of particles from the viewpoint of film slipperiness and air escapeability. It is preferable to contain, in particular, silica particles and / or calcium carbonate particles. The content of particles contained is preferably 5,000 to 15,000 ppm in total of particles in the surface layer B. At this time, the area average surface roughness (Sa) of the film of the surface layer B is preferably in the range of 1 to 40 nm. More preferably, it is in the range of 5 to 35 nm. When the total of the silica particles and / or calcium carbonate particles 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, and the winding appearance is good. The good planarity makes it suitable for the production of ultra-thin ceramic green sheets. In addition, when the total amount of silica particles and / or calcium carbonate particles is 15000 ppm or less and Sa is 40 nm or less, aggregation of the lubricant is difficult to occur and coarse protrusions can not be formed, so the ceramic green sheet of ultrathin layer is wound after molding Even in this case, the ceramic green sheet is preferable without causing defects such as pinholes.

As 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. In addition to silica and / or calcium carbonate, inert inorganic particles and / or heat resistant organic particles can be used, and examples of other inorganic particles that can be used include alumina-silica composite oxide particles, hydroxyapatite particles, etc. Be Further, as the heat resistant organic particles, crosslinked polyacrylic particles, crosslinked polystyrene particles, benzoguanamine particles and the like can be mentioned. When silica particles are used, porous colloidal silica is preferable, and when calcium carbonate particles are used, light calcium carbonate which has been surface-treated with a polyacrylic acid-based polymer compound is preferable from the viewpoint of preventing the slippage of the lubricant. .

The average particle diameter of the particles added to the surface layer B is preferably 0.1 μm to 2.0 μm and particularly preferably 0.5 μm to 1.0 μm. If the average particle size of the particles is 0.1 μm or more, the slipperiness of the release film is good and preferable. In addition, if the average particle diameter is 2.0 μm or less, there is no possibility of generation of pinholes due to coarse particles on the surface of the release layer, which is preferable. In addition, the measuring method of the average particle diameter of particle | grains observes the particle of the cross section of the film after a process with a scanning electron microscope, observes 100 particle | grains, and carries out it by the method of making it the average particle diameter Can. The shape of the particles is not particularly limited as long as the object of the present invention is satisfied, and spherical particles and irregular-shaped non-spherical particles can be used. The particle diameter of the irregularly shaped particles can be calculated as the equivalent circle diameter. The equivalent circle diameter is a value obtained by dividing the area of the observed particles by the circular constant (π), calculating the square root and doubling it.

The surface layer B may contain two or more types of particles different in material. Also, particles of the same type but different in average particle size may be contained.

In the case where the surface layer B does not contain particles, it is also preferable to make the surface layer B have a lubricity by a coat layer containing the particles. Although the means to provide this coating layer is not specifically limited, It is preferable to provide by what is called the in-line coating method coated in film forming of a polyester film. Moreover, when providing the coat layer which gives slipperiness to the surface of the side which does not laminate the mold release layer of a polyester film, the polyester film does not need to have the surface layers A and B, and it is necessary to May be composed of a single-layer polyester film not contained.

The area average surface roughness (Sa) of the surface layer B is preferably 40 nm or less, more preferably 35 nm or less, and still more preferably 30 nm or less. Also, when the surface layer B or the surface of the single-layer polyester film not to be laminated is provided with lubricity by the coat layer (D), Sa on the surface is the surface on which the coat layer is laminated. It is preferable that the area of the surface layer B be in the same range as the surface average roughness (Sa).

(Coat layer D)
Preferably, 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)
Although it does not specifically limit as a binder resin which comprises a lubricious application layer, As a specific example of a polymer, a polyester resin, an acrylic resin, a urethane resin, polyvinyl-type resin (polyvinyl alcohol etc.), polyalkylene glycol, polyalkyleneimine, methylcellulose , Hydroxycellulose, starches and the like. Among these, it is preferable to use a polyester resin, an acrylic resin, or a urethane resin from the viewpoint of retention of particles and adhesion. In addition, polyester resins are particularly preferable in consideration of familiarity with polyester films. In order to achieve the solubility in solvents, the dispersibility, and the adhesion to the substrate film and other layers, the polyester of the binder is preferably a copolyester. The polyester resin may be polyurethane-modified. Moreover, urethane resin is mentioned as another preferable binder resin which comprises the easily slipping coating layer on a polyester base film. Polycarbonate polyurethane resin is mentioned as a urethane resin. Furthermore, polyester resin and polyurethane resin may be used in combination, and the other binder resin described above may be used in combination.

(Cross-linking agent for coat layer D)
In the present invention, in order to form a crosslinked structure in the slippery coating layer, the slippery coating layer may be formed to contain a crosslinking agent. By including the crosslinking agent, it is possible to further improve the adhesion under high temperature and high humidity. Specific examples of the crosslinking agent include ureas, epoxys, melamines, isocyanates, oxazolines, carbodiimides, and aziridine. Moreover, in order to accelerate | stimulate a crosslinking reaction, a catalyst etc. can be used suitably as needed.

(Particles in the 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, ground calcium carbonate, zeolite, alumina, Barium sulfate, carbon black, zinc oxide, zinc sulfate, zinc carbonate, zirconium oxide, titanium dioxide, satin white, aluminum silicate, diatomaceous earth, calcium silicate, aluminum hydroxide, hydrolysed 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 / Iso Although organic particles such as styrene, methyl methacrylate / butyl methacrylate, melamine, polycarbonate, urea, epoxy, urethane, phenol, diallyl phthalate, polyester, etc. may be mentioned, suitable for the coating layer Silica is particularly preferably used to impart slip properties.

The average particle diameter of the particles is preferably 10 nm or more, more preferably 20 nm or more, and still more preferably 30 nm or more. When the average particle diameter of the particles is 10 nm or more, aggregation is difficult and slipperiness can be secured, which is preferable.

The average particle diameter of the particles is preferably 1000 nm or less, more preferably 800 nm or less, and still more preferably 600 nm or less. Transparency is maintained as the average particle diameter of particle | grains is 1000 nm or less, and it is preferable without particle | grains falling off.

For example, it is also possible to mix small particles with an average particle diameter of about 10 to 270 nm and large particles with an average particle diameter of about 300 to 1000 nm, the area surface average roughness (Sa) described below, and the maximum projection height ( It is preferable to keep the average length (RSm) of the roughness curvilinear element small and keep slipperiness and smoothness compatible while keeping the RP) small, and particularly preferred is a small particle of 30 nm or more and 250 nm or less, and an average particle It is to use large particles having a diameter of 350 to 600 nm in combination. When small particles and large particles are mixed, it is preferable to make the mass content of small particles larger than the mass content of 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 recycled raw materials or the like in the surface layer A, which is the layer on which the release layer is provided, in order to prevent mixing of particles such as a lubricant.

It is preferable that the thickness ratio of surface layer A which is a layer at the side which provides the said mold release layer is 20% or more and 50% or less of the total layer thickness of a base film. If it is 20% or more, the influence of particles contained in the surface layer B or the like is not easily received from the inside of the film, and the area surface average roughness Sa easily meets the above range, which is preferable. The use ratio of the reproduction | regeneration raw material in surface layer B can be increased as it is 50% or less of the thickness of the whole layer of a base film, an environmental impact is small and preferable.

Further, from the viewpoint of economy, 50 to 90% by mass of film scraps and plastic bottle recycled raw materials can be used for the layers other than the surface layer A (surface layer B or 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 diameter, and the area surface average roughness (Sa) satisfy the above range.

In addition, a film after stretching or uniaxial stretching in the film forming process on the surface of the surface layer A and / or the surface layer B in order to improve adhesion of a release layer applied later or to prevent charging etc. May be provided with a coating layer, or may be subjected to corona treatment or the like. When a coat layer is also provided, Sa of each layer is substituted by the measurement value of the coat layer surface. Moreover, when providing these coat layers on the surface of surface layer A, it is preferable not to contain particle | grains.

(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 to cure the coating film containing at least the resin (II) forming the resin and the mold release component (III). By forming the sea-island structure by the phase separation of the energy ray-curable compound (I) and the resin (II), it is possible to easily form asperities with an appropriate height, and no coarse projections are generated. No holes occur. In addition, since the flat portion is almost absent and peeling occurs at points, even a brittle ultra-thin ceramic green sheet can be peeled without dipping, so that damage such as cracking or deformation can be suppressed. .

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

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

The energy ray-curable compound having a (meth) acryloyl group can be used without limitation to monomers, oligomers and polymers. Further, it is preferable to contain a compound having three or more reactive groups in at least one molecule, but two or more compounds such as a compound having one or two reactive groups in the molecule are mixed and used. It can also be done. By mixing a compound having a small number of reactive groups, curling and the like can be suppressed.

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

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

Examples of energy ray curable oligomers having 3 or more (meth) acryloyl groups in the molecule include urethane acrylate, polyester acrylate, polyether acrylate, epoxy acrylate, silicone modified acrylate, etc. It can be used. For example, beam set (registered trademark) series manufactured by Arakawa Chemical Industries, NK Oligo series manufactured by Shin-Nakamura Chemical Co., Ltd. EBECRYL series manufactured by Daicel Ornex Co., Ltd., biscoat series manufactured by Osaka Organic Chemical Industry Co., Ltd., urethane acrylate series manufactured by Kyoeisha Chemical 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 in which (meth) acryloyl groups are grafted to the polymer, block polymers in which a polyfunctional acrylic monomer is added to the polymer end, etc. Can be mentioned. As the polymers as described above, acrylic resin, epoxy resin, polyester resin, polyorganosiloxane and the like can be used, and it 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 a coating agent, but after application, the solvent is dried. It is preferable to form a sea-island structure by using the energy ray-curable compound (I) as the sea component and the resin (II) as the island component, since they are mutually incompatible in the release layer formed through curing. (II) can be used without particular limitation as long as the above requirements are satisfied. Two or more resins can also be used simultaneously. The content of the resin (II) in the solid content in the release layer-forming coating solution is preferably 1 to 40% by mass, and more preferably 1 to 10% by mass. Sufficient unevenness can be formed by containing 1% by mass or more, and by setting the amount to 40% by mass or less, the degree of crosslinking of the release layer is high, and the temperature dependency at peeling is low, which is preferable.

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

The polyester resin is not particularly limited, and commercially available resins can be used. For example, Bayon (registered trademark) series manufactured by Toyobo Co., Ltd., Nichigo Polyester (registered trademark) series manufactured by Nippon Synthetic Chemical Industry Co., Ltd., and the like can be mentioned.

The acrylic resin is an oligomer or a polymer obtained by polymerizing an acrylic ester, and may be a homopolymer or a copolymer. Moreover, a commercially available thing can be used. For example, the acryl Corporation (registered trademark) series ARICON (trade name) manufactured by Toagosei Co., Ltd. and the like, and the like may be mentioned.

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

(Release component (III))
The releasing component (III) used in the present invention is not particularly limited as long as it is a material capable of exhibiting releasing property with the green sheet, such as polyorganosiloxane, fluorine compound, long chain alkyl compound, and waxes. Moreover, the material which has a functional group which can react and couple | bond with energy-beam-curable compound (I) which has a (meth) acryloyl group etc. to these materials is preferable. Also, two or more kinds of materials can be mixed and used. The content of the release component (III) in the solid content in the release layer-forming coating solution is preferably 0.05 to 10% by mass, and more preferably 0.1 to 5% by mass. If the content is 0.05% by mass or more, the peeling force can be lightened, and if the content is 10% by mass or less, the transfer of the releasing component to the ceramic green sheet or the like can be suppressed, which is preferable.

As polyorganosiloxanes, in addition to polydimethylsiloxane, polydiethylsiloxane, polyphenylsiloxane, etc., siloxane compounds having a partial organic modification, block polymers having polyorganosiloxanes, polymers obtained by grafting polyorganosiloxanes, etc. It can be used. As a commercially available product, for example, BYK (registered trademark) series manufactured by Big Chemie Japan Co., Ltd., 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, Megafuck (registered trademark) series manufactured by DIC Corporation can be mentioned.

Examples of long chain alkyl compounds include acrylic polymers copolymerized with long chain alkyl acrylates, graft polymers grafted with long chain alkyl, and block polymers with long chain alkyl end-added. Moreover, it does not specifically limit, A commercially available thing can be used. For example, Tesfine (registered trademark) series manufactured by Hitachi Chemical Co., Ltd., and Peiroil (registered trademark) manufactured by Lion Specialty Chemicals, etc. may be mentioned.

Examples of the active energy ray include infrared rays, visible rays, ultraviolet rays, electromagnetic waves such as X-rays, electron beams, ion beams, particle rays such as neutrons and alpha rays, and the like, among them, the production cost It is preferable to use excellent ultraviolet light.

The atmosphere when the active energy ray is irradiated may be a general air or a nitrogen gas atmosphere. In a nitrogen gas atmosphere, the radical reaction can proceed smoothly by reducing the oxygen concentration, and the elastic modulus of the release layer can be improved. It is preferable from the economical point of view.

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

Although the addition amount of a photoinitiator is not specifically limited, For example, it is preferable to contain about 0.1 to 20 mass% as solid content in the coating liquid for release layer formation.

The releasing layer in the present invention can contain particles having a particle diameter of 1 μm or less, but it is preferable not to contain particles forming projections such as particles from the viewpoint of generation of pinholes.

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 effects of the present invention are not impaired. Further, in order to improve the adhesion to the substrate, it is also preferable to subject the polyester film surface to pretreatment such as anchor coating, corona treatment, plasma treatment, atmospheric pressure plasma treatment or the like before the release coating layer is provided.

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 range from 0.2 to 3.5 μm of the release layer after curing is preferable. More preferably, it is 0.5 to 3.0 μm. When the thickness of the release layer is 0.2 μm or more, the curability of the energy ray-curable copolymer is good, and the elastic modulus of the release layer is improved. Further, when the thickness is 3.5 μm or less, curling is unlikely to occur even when the thickness of the release film is reduced, and thus it is preferable because the running property is not deteriorated in the process of molding and drying the ceramic green sheet.

In the release film of the present invention, it is preferable that the surface of the release layer has appropriate irregularities. Therefore, it is preferable that the area surface average roughness (Sa) of the release layer surface is 5 to 40 nm. Further, it is more preferable that the above-mentioned Sa is satisfied, and the maximum projection height (Rp) on the surface of the releasing layer is 60 nm or less. Furthermore, the area surface average roughness (Sa) is preferably 5 to 20 nm, and more preferably 8.5 to 20 nm. At the same time, it is particularly preferred that the maximum projection height (Rp) be 50 nm or less. When the area surface roughness (Sa) is 5 nm or more, the zipping can be reduced at the time of peeling of the ceramic green sheet, and even an ultrathin layer green sheet can be easily peeled without damage. When the area surface roughness (Sa) is 40 nm or less, the particle size of the ceramic is sufficiently smaller than the particle size of the ceramic, and the surface shape of the green sheet is not affected. If the above-mentioned Sa is satisfied and the maximum projection height (Rp) on the surface of the releasing layer is 60 nm or less, the possibility of causing a pinhole defect is further reduced, which is preferable. Although the maximum projection height (Rp) is preferably small, the maximum projection height (Rp) may also be 5 nm or more, 10 nm or more, because the area surface average roughness (Sa) is adjusted to 5 nm or more. It does not matter. In order to adjust the surface roughness (Sa) and the maximum projection height (Rp) of the release layer as described above, various factors are related, but mainly the surface layer A of the polyester film 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. A curable compound (I) and the energy beam curable compound (I) as a sea component, and a resin (II) which is incompatible with the energy beam curable compound (I) and becomes an island component, are cured It can be said that what is being done is related. The method of adjusting the surface roughness (Sa) and the maximum projection height (Rp) of the release layer to the appropriate range as described above is not particularly limited, but mainly the energy ray-curable compound (I) and the resin ( This can be achieved preferably by adjusting the combination and content ratio of the materials of II).

The static friction coefficient of the release layer surface of the release layer film of the present invention is preferably 0.05 or more and 2.00 or less. More preferably, it is 0.1 or more and 1.00 or less, and still more preferably 0.1 or more and 0.50 or less. If the coefficient of static friction is within the above range, the surface of the coating layer and the surface of the mold release layer slip well and no excessive force is applied, so the damage to the surface of the mold release layer is reduced and damage to the green sheet is reduced. And a good green sheet surface is obtained.
Moreover, it is preferable that the dynamic friction coefficient of the mold release layer surface of the mold release film of this invention is 1.00 or less. Within the above range, a good green sheet surface can be obtained without tension abnormality occurring in 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 projection height (Rp) of the release layer, and the adjustment method There is no particular limitation, but 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 releasing layer is not particularly limited, and a coating liquid in which a releasing compound is dissolved or dispersed is spread on one surface of the polyester film of the substrate by coating etc. The method of making it harden | cure after removing by drying is used.

It is preferable that the drying temperature of solvent drying in the case of apply | coating the release layer of this invention on a base film by solution application is 50 degreeC or more and 120 degrees C or less, and is 60 degrees C or more and 100 degrees C or less More preferable. The drying time is preferably 30 seconds or less and more preferably 20 seconds or less. Furthermore, after solvent drying, it is preferable to irradiate an active energy ray to advance the curing reaction. As the active energy ray used at this time, ultraviolet rays, electron beams, X-rays, etc. can be used, but ultraviolet rays are preferred because they are easy to use. The amount of ultraviolet light to be irradiated is preferably 30 to 300 mJ / cm ² , and more preferably 30 to 200 mJ / cm ² in light amount. By setting it to 30 mJ / cm ² or more, the curing of the composition proceeds sufficiently, and by setting it to 300 mJ / cm ² or less, the processing speed can be improved, so that the mold 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 coating property after coating can be improved, and unevenness on the surface of the coated film after drying can be reduced.

Any known coating method can be applied as the coating method of the above coating solution, for example, roll coating such as gravure coating or reverse coating, bar coating such as wire bar, die coating, spray coating, air knife A conventionally known method such as a coating method can be used.

EXAMPLES The present invention will be described by way of examples to describe the present invention in detail, 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) Substrate film thickness By using Millitron (electronic micro indicator), 4 pieces of 5 cm square samples are cut out from any 4 parts of the film to be measured, and each 5 pieces (20 pieces in total) are measured and averaged Thickness.

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

(3) Region surface roughness (Sa), maximum projection height (Rp)
It is a value measured under the following conditions using a non-contact surface shape measurement system (VertScan R550H-M100, manufactured by Ryoka System Co., Ltd.). The area surface average roughness (Sa) was an average value of 5 measurements, and the maximum projection height (Rp) was 7 measurements, and the maximum value of 5 values excluding the maximum value and the minimum value was used.
(Measurement condition)
-Measurement mode: WAVE mode-Objective lens: 50x-0.5 x Tube lens (analysis conditions)
-Face correction: 4th order correction-Interpolation: Complete interpolation

(4) Pinhole Evaluation of 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 with 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 Co., Ltd.) 35.0 parts by mass Polyvinyl butyral 3.5 parts by mass (S-Rec (registered trademark) BM-S manufactured by Sekisui Chemical Co., Ltd. )
Next, 1.8 parts by mass of DOP (dioctyl phthalate) is applied to the release surface of the release film sample using an applicator so that the ceramic green sheet after drying is 0.8 μm and dried at 90 ° C. for 2 minutes, The release film was peeled off to obtain a ceramic green sheet.
In the central region of the film width direction of the obtained ceramic green sheet, light is applied from the opposite surface of the ceramic slurry application surface in the range of 25 cm ² , and the occurrence of pinholes where light is seen to be transmitted is observed. It judged visually. The measurement was performed 5 times and the average value was adopted.
○: Occurrence of pinholes is almost nonexistent (estimate: no more than 2 pinholes per measurement area)
Δ: occurrence of pinholes (indication: 3 or more, 5 or less pinholes per measurement area) ×: many occurrence of pinholes (indication: 6 or more pinholes per measurement area)

(5) Evaluation of damage to ceramic green sheet The release film with a ceramic green sheet prepared by the above method was cut into a width of 30 mm and a length of 80 mm, and used as a sample for measurement of peel force. After removing electricity using an electric discharge machine (manufactured by Keyence Corporation, SJ-F020), using a peeling tester (VPA-3 manufactured by Kyowa Interface Science Co., Ltd.), the peeling angle is 30 degrees, the peeling temperature is 25 ° C., and the peeling speed is 10 m / m. It peeled in min. As a peeling direction, a double-sided adhesive tape (Nitto Denko Co., Ltd., No. 535A) is stuck on a SUS plate attached to a peeling tester, and a release film is formed by bonding the ceramic green sheet side to the double-sided tape on it. Were fixed and peeled off in the form of pulling the release film side. With respect to the surface of the ceramic green sheet after peeling, which was in contact with the mold release film, a range of 1250 μm × 900 μm was observed 100 times with a scanning electron microscope in the central region in the film width direction, and an average value measured ten times was adopted. . It judged visually according to the following standard.

○: no damage at peeling (indication: no occurrence of cracks and deformation)
:: Mild damage occurred during peeling (Indication: 1 or more and 3 or less cracks and deformations per measurement area)
X: There is severe damage at the time of exfoliation (Indication: 4 or more cracks and deformations)

In addition, the peeling angle in this evaluation method points out the angle of the direction which pulls a release film with respect to the evaluation sample axis fixed to the peeling test machine. The peeling temperature is a temperature at which the release film fixed by using a heater type stage system attached to the apparatus is heated. Peeling is performed after confirming that the temperature of the measurement sample has reached the relevant temperature using a handy type thermometer (HD-1400E, manufactured by Anritsu Keiki Co., Ltd.).

(6) Coefficient of static friction, coefficient of dynamic friction When using a Tensilon universal tester (RTG-1210, manufactured by A & D Co., Ltd.), the mold release layer surface of the film is overlapped with the SUS plate in contact with it The static friction coefficient (μs) and the dynamic friction coefficient (μd) of the contact surface were measured in accordance with JIS K-7125 under the following conditions.

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

(Preparation of polyethylene terephthalate pellets (PET (1)))
As an esterification reaction apparatus, a continuous esterification reaction apparatus was used which was composed of a three-stage complete mixing tank having a stirrer, a partial condenser, a raw material feed port and a product outlet. TPA (terephthalic acid) is 2 tons / hour, EG (ethylene glycol) is 2 moles with respect to 1 mole of TPA, antimony trioxide is produced in an amount such that 160 ppm of Sb atoms are formed with respect to PET, and these slurries are ester The reaction mixture was continuously fed to the first esterification reactor of the esterification reactor, and reacted at 255 ° C. for 4 hours at an average residence time under normal pressure. Then, the reaction product in the first esterification reaction vessel is continuously taken out of the system, supplied to the second esterification reaction vessel, and distilled from the first esterification reaction vessel in the second esterification reaction vessel. The EG solution contains 8% by weight of EG to the produced PET, and further contains an EG solution containing magnesium acetate tetrahydrate in an amount of 65 ppm of Mg atoms to the produced PET, and 40 ppm of P atoms to the produced PET The EG solution containing the following amount of TMPA (trimethyl phosphate) was added, and the reaction was carried out at 260.degree. C. under an atmospheric pressure for an average residence time of 1 hour. Then, the reaction product of the second esterification reaction vessel is continuously taken out of the system, supplied to the third esterification reaction vessel, 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 with an average particle size of 0.9 μm dispersed with an average pressure of 5 passes and an average particle of 1% by mass per ammonium carbonate of an ammonium salt of polyacrylic acid While adding 0.4 mass% of synthetic calcium carbonate having a diameter of 0.6 μm as an EG slurry of 10% each, the reaction was carried out at 260 ° C. at an average residence time of 0.5 hours under normal pressure. The esterification reaction product generated in the third esterification reaction vessel was continuously supplied to a three-stage continuous polycondensation reaction apparatus to conduct polycondensation, and a 95% cut diameter sintered a 20 μm stainless steel fiber After filtration with a filter, it was ultrafiltered and extruded in water, and after cooling it was 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 manufacture of the above 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 referred to as PET (2)).

(Preparation of polyethylene terephthalate pellets (PET (3)))
The type and content of particles of PET (I) were changed to 0.75% by mass of synthetic calcium carbonate having an average particle diameter of 0.9 μm, in 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 referred to as PET (3)). The lubricant content in the PET chip was 0.75% by mass.

(Manufacture of laminated film X1)
After drying, these PET chips are melted at 285 ° C., melted at 290 ° C. by a separate melt extruder extruder, and a 95% cut diameter sintered filter of 15 μm stainless steel fibers, 95% cut diameter Two-stage filtration of a filter made of sintered 15 μm stainless steel particles is carried out and merged in a feed block to make PET (1) a surface layer B (a reverse surface side layer), PET (2) a surface Layer A (release surface side layer) is laminated, extruded in a sheet shape at a speed of 45 m / min (casting), and electrostatically adhered and cooled on a casting drum at 30 ° C. by an electrostatic adhesion method. An unstretched polyethylene terephthalate sheet having an intrinsic viscosity of 0.59 dl / g was obtained. The layer ratio was adjusted so that PET (1) / (2) = 60% / 40% in discharge amount calculation of each extruder. Next, this unstretched sheet was heated by an infrared heater and then stretched 3.5 times in the longitudinal direction at a roll temperature of 80 ° C. due to the speed difference between the rolls. Thereafter, it was introduced into a tenter and stretched 4.2 times in the transverse direction at 140 ° C. It was then heat treated at 210 ° C. in the heat setting zone. Thereafter, the film was subjected to a relaxation treatment at 2.3 ° C. in the horizontal direction at 170 ° C. to obtain a 31 μm-thick biaxially stretched polyethylene terephthalate film X1. 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.

(Production of laminated film X2)
The thickness was adjusted by changing the speed at the time of casting without changing the layer configuration and the stretching conditions similar to the laminated film X1 to obtain a biaxially stretched polyethylene terephthalate film X2 having a thickness of 25 μm. In the surface layer A of the obtained film X2, Sa was 3 nm, and 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 the structure which provided the coating layer which contained particle | grains by in-line coating in the surface layer B side substantially without containing particle | grains in a film. Sa of the surface layer A of the laminated film X3 was 1 nm, and Sa of the surface layer B was 2 nm.

Example 1
Apply coating solution 1 of the following composition onto the surface layer A of the laminated film X1 using reverse gravure so that the thickness of the release layer after drying is 2.5 μm, and after drying for 30 seconds at 90 ° C., high pressure A release film for producing an ultrathin ceramic green sheet was obtained by irradiating ultraviolet rays so as to be 200 mJ / cm ² using a mercury lamp. The release film thickness, area surface roughness Sa, maximum protrusion height Rp, pinhole evaluation of ceramic green sheet, damage evaluation to ceramic green sheet, static friction coefficient, dynamic friction coefficient are evaluated for the obtained release film. The

(Coating solution 1)
Compound (I) 100.00 parts by mass
(Dipentaerythritol hexaacrylate, Shin-Nakamura Chemical Co., Ltd. A-DPH, solid concentration 100%)
Resin (II) Polyester resin 9.47 parts by mass (Toyobo Co., Ltd. Byron (registered trademark) RV 280, solid content concentration 100% by mass)
Release agent (III) 1.26 parts by mass (modified polydimethylsiloxane having an acryloyl group, BYK-UV 3505, manufactured by Byk Chem Japan, solid content 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)
Diluted solvent (MEK / toluene = 1/1) 459.79 parts by mass

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

(Coating solution 2)
Compound (I) 100.00 parts by mass (Dipentaerythritol hexaacrylate, Shin-Nakamura Chemical Co., Ltd. A-DPH, 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 mass%)
Release agent (III) 0.42 parts by mass (Modified polydimethylsiloxane having an acryloyl group, BYK-UV 3505, manufactured by Bick 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)
Diluted solvent (MEK / toluene = 1/1) 975.42 parts by mass

(Example 3)
The following coating solution 3 was used, in which the proportion of the releasing agent (III) was increased as compared with that in Example 2. It applied so that the release layer film thickness after drying might be set to 1.8 micrometers. A release film was obtained in the same manner as in Example 1 except that the coating solution 3 was used and the coating was performed so that the thickness of the release layer after drying was 1.8 μm. The release film thickness, area surface roughness Sa, maximum protrusion height Rp, pinhole evaluation of ceramic green sheet, damage evaluation to ceramic green sheet, static friction coefficient, dynamic friction coefficient are evaluated for the obtained release film. The

(Coating solution 3)
Compound (I) 100.00 parts by mass (Dipentaerythritol hexaacrylate, Shin-Nakamura Chemical Co., Ltd. A-DPH, 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 mass%)
Release agent (III) 1.26 parts by mass (modified polydimethylsiloxane having an acryloyl group, BYK-UV 3505, manufactured by Byk Chem Japan, solid content 40% by mass)
Photopolymerization initiator 5.25 parts by mass (OMNIRAD (registered trademark) 907, manufactured by IGM Japan GK, solid content 100% by mass)
Diluted solvent (MEK / toluene = 1/1) 982.98 parts by mass

(Example 4)
The coating solution 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 release film thickness, area surface roughness Sa, maximum protrusion height Rp, pinhole evaluation of ceramic green sheet, damage evaluation to ceramic green sheet, static friction coefficient, dynamic friction coefficient are evaluated for the obtained release film. The

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

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

(Coating solution 4)
Compound (I) 100.00 parts by mass (Dipentaerythritol hexaacrylate, Shin-Nakamura Chemical Co., Ltd. A-DPH, solid content concentration 100%)
Releasing agent (III) 1.00 parts by mass (Acryloyl group-containing polyether-modified polydimethylsiloxane BYK UV-3500, 100% solid concentration by Big Chemie Japan)
Photopolymerization initiator 5.00 parts by mass (OMNIRAD (registered trademark) 907, IGM Japan GK company solid content concentration 100 mass%)
Diluted 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 peeling force does not become too heavy as compared with the conventional release film for producing a ceramic green sheet, and the processability is excellent and the release layer is large. Since there is no protrusion, it has become possible to provide a release film for producing a ceramic green sheet capable of reducing defects such as pinholes in an ultrathin ceramic green sheet having a thickness of 1 μm or less.

Claims (7)

1. A release film in which a release layer of 0.2 to 3.5 μm is laminated on at least one surface of a polyester film directly or through another layer, and the area surface roughness (Sa) of the release layer surface is A release film for producing a ceramic green sheet, having a maximum peak height (Rp) of 60 nm or less and 5 to 40 nm.
2. An energy ray-curable compound (I), wherein the releasing layer has three or more reactive groups in one molecule, and the energy ray-curable compound (I) as a sea component, the energy ray-curable compound (I) The release film for producing a ceramic green sheet according to claim 1, wherein the coating film containing at least the resin (II) which is incompatible with the resin and which becomes the island component and the release component (III) is cured.
3. The release film for producing a ceramic green sheet according to claim 1 or 2, wherein the release layer contains substantially no inorganic particles.
4. The polyester film is a laminated polyester film comprising at least a surface layer A and two or more layers including a surface layer B opposite to the surface layer A, and a release layer is laminated on the surface layer A. 4. The release film for producing a ceramic green sheet according to any one of claims 1 to 3, wherein the surface layer A is substantially free of inorganic particles.
5. The surface layer B contains particles, the particles are silica particles and / or calcium carbonate particles, and the total content of particles is 5,000 to 15,000 ppm with respect to the total mass of the surface layer B. Release film for ceramic green sheet production.
6. The ceramic according to any one of claims 1 to 3, wherein the polyester film is substantially free of inorganic particles, and the coating layer containing the particles is laminated on the side of the polyester film on which the release layer is not laminated. Release film for green sheet production.
7. A method for producing a ceramic green sheet, wherein the ceramic green sheet is molded using the mold release film for producing a ceramic green sheet according to any one of claims 1 to 6, wherein the molded ceramic green sheet has a thickness of 0.2 μm to 1 A method of producing a ceramic green sheet having a thickness of 0 μm.