JP2018144500A - Release film for producing ceramic green sheet, and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a release film for producing a ceramic green sheet, in which a release film at least includes a binder resin and a silicone based resin, in which deterioration in the surface roughness caused by the flocculation upon the drying of the components is suppressed, having high smoothness and excellent detachability, and a method for producing the release film.SOLUTION: There is provided a release film for producing a ceramic green sheet using a polyester film as a base material, in which the base material contains a surface layer A not substantially including particles at least on either side, and a release layer is laminated on the surface of the surface layer A at least of either side directly or via the other layer, in which a curl after heating at 100°C for 15 minutes without applying tension is 2 mm or lower, the release layer includes a binder component and a silicone based release agent, and the maximum projection height (P) of the surface of the release layer is 50 nm or lower.SELECTED DRAWING: None

Description

  The present invention relates to a release film for producing a ceramic green sheet, and more specifically, an ultra-thin layer capable of producing a ceramic green sheet having an ultra-thin layer in which occurrence of process defects due to pinholes and thickness unevenness can be suppressed. The present invention relates to a release film for producing a ceramic green sheet.

  In recent years, with the reduction in size and capacity of multilayer multilayer ceramic capacitors (abbreviated as MLCC), there has been a demand for thinner ceramic green sheets. Multilayer multilayer ceramic capacitors are coated with a slurry containing a ceramic component such as barium titanate and a binder resin on a release film and dried to form a ceramic green sheet, and electrodes are printed on the resulting ceramic green sheet Then, it is peeled from the release film, laminated and pressed with a ceramic green sheet, degreased and fired, and then coated with an external electrode.

  In order to increase the size and capacity of MLCC, it is necessary to reduce the thickness of the ceramic green sheet. The film thickness is 1.0 μm or less, and further 0.6 μm or less. Progress is also being made. However, when the ceramic green sheet is thinned, there is a problem that defects such as pinholes and cracks are likely to occur due to extremely fine protrusions on the release film and the force when peeling from the release film.

In order to solve these problems, as a release film used for molding a ceramic green sheet, a film in which a release layer is provided on a polyester film and the release layer surface is highly smoothed has been proposed. Patent Document 1 discloses that a smoothing layer is provided on the surface of a polyester film, and then a release layer is provided on the smoothing layer. Patent Document 2 discloses that a release layer composed of a (meth) acrylic acid ester and a silicone component is formed with a film thickness of 0.3 μm or more. Patent Document 1 and Patent Document 2 disclose that the arithmetic average roughness Ra of the release layer surface can be 8 nm or less and the maximum protrusion height Rp can be 50 nm or less.

  However, in Patent Documents 1 and 2, since the thickness of the resin layer (release layer and smoothing layer) laminated on the polyester film is thick, it takes time to cure and the amount of organic solvent to be used increases, so the environmental load is large. There were issues such as. In addition, since the release layer is thick, curling of the obtained release film may be a problem.

  In addition, the following proposals have been made as a release layer of a release film for forming a ceramic green sheet. Patent Document 3 proposes a non-silicone release layer that does not contain silicone in the release layer. Patent Document 4 proposes a film using a silicone resin as a release layer. However, if it is a non-silicone release layer as in Patent Document 3, the peeling force when peeling the ceramic green sheet is increased, and the thinned ceramic green sheet has a problem of being damaged. In addition, in the release layer of the silicone resin as in Patent Document 4, the peeling force when peeling the ceramic green sheet is small, but since the glass transition temperature of the silicone resin is generally below room temperature, the elastic modulus is low. There is a problem that the peeling force becomes unstable because the release layer is deformed at the time of peeling.

  On the other hand, Patent Document 5 proposes a release layer containing melamine resin and polyorganosiloxane. It has been proposed to mainly contain a melamine resin as a binder for the release layer and to add a silicone resin as a release component to increase the elastic modulus of the release layer to achieve both deformability and peelability. .

  However, if the release layer contains a binder resin and a silicone resin, the solubility of the binder resin and the silicone resin in the organic solvent and the surface tension of the solution are greatly different. Agglomerates to form protrusions, and there is a problem of deteriorating the surface roughness of the release layer surface. When a ceramic green sheet having a thickness of 1.0 μm or less, further 0.6 μm or less is molded, the defect rate of a multilayer ceramic capacitor that can generate pinholes and the like is deteriorated even when the surface roughness is so small. Further smoothness has been demanded.

JP 2014-177093 A International Publication No. 2013/145864 JP 2010-144046 A JP 2012-207126 A JP 2017-7226 A

  In view of the above circumstances, the present invention includes at least a binder resin and a silicone resin as a release layer of a release film for producing a ceramic green sheet, and suppresses deterioration of surface roughness due to aggregation of the above components during drying. An object of the present invention is to provide a release film having smoothness and excellent peelability and a method for producing the release film.

That is, the present invention has the following configuration.
1. A polyester film is used as a base material, and the base material has a surface layer A substantially free of particles on at least one side, and is released directly on the surface of the surface layer A on at least one side or via another layer. A release film in which layers are laminated, and the curl after heating at 100 ° C. for 15 minutes without applying tension is 2 mm or less, and the release layer contains a binder component and a silicone release agent, A release film for producing a ceramic green sheet, wherein the maximum protrusion height (P) on the surface of the release layer is 50 nm or less.
2. 2. The release film for producing a ceramic green sheet according to the first aspect, wherein the binder component contained in the release layer contains a resin having a long-chain alkyl group and / or a silicone skeleton.
3. The release agent for producing a ceramic green sheet according to claim 1 or 2, wherein the silicone-based release agent has a polyether moiety and is contained in a release layer in an amount of 0.1 to 20% by mass. Mold film.
4). A method for producing a ceramic green sheet using the release film for producing a ceramic green sheet according to any one of the first to third aspects, wherein the molded ceramic green sheet has a thickness of 0.2 μm to A method for producing a ceramic green sheet having a thickness of 1.0 μm.
5. A method for producing a ceramic capacitor, wherein the method for producing a ceramic green sheet according to the fourth aspect is adopted.

  Also in the production of ultra-thin ceramic green sheets having a film thickness of 0.2 to 1.0 μm, a release film for producing ceramic green sheets that has good peelability and can reduce defects such as pinholes and its efficiency New manufacturing methods can be provided.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a polyester film having a surface layer A that does not substantially contain particles on at least one side is directly or via another layer on the surface layer A on at least one side. A release film formed by laminating a release layer having a film thickness of 0.2 μm or less, containing a binder resin and a silicone resin in the release layer, and having a maximum protrusion height (P) on the surface of the release layer The present invention has found a release film for producing a ceramic green sheet characterized by having a thickness of 50 nm or less and an arithmetic average roughness (Sa) of 1.5 nm or less, and a production method for efficiently producing the release film.
Hereinafter, the present invention will be described in detail.

(Polyester film)
In the present invention, the polyester constituting the polyester film used as the substrate is not particularly limited, and it is possible to use a film-molded polyester that is generally used as a release film substrate. A linear linear saturated polyester composed of an aromatic dibasic acid component and a diol component, such as polyethylene terephthalate, polyethylene-2,6-naphthalate, polybutylene terephthalate, polytrimethylene terephthalate or a resin thereof. A copolymer having the above component as a main component is more preferable, and a polyester film formed from polyethylene terephthalate is particularly preferable. In polyethylene terephthalate, the repeating unit of ethylene terephthalate is preferably 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. Those produced only from terephthalic acid and ethylene glycol are preferred. Moreover, you may add a well-known additive, for example, antioxidant, a light stabilizer, a ultraviolet absorber, a crystallizing agent, etc. within the range which does not inhibit the effect of the film of this invention. The polyester film is preferably a biaxially oriented polyester film for reasons such as high bidirectional elasticity.

  The intrinsic viscosity of the polyethylene terephthalate film is preferably 0.50 to 0.70 dl / g, and more preferably 0.52 to 0.62 dl / g. When the intrinsic viscosity is 0.50 dl / g or more, it is preferable because many breakage does not occur in the stretching process. On the other hand, when it is 0.70 dl / g or less, it is preferable because cutting property when cutting to a predetermined product width is good and dimensional defects do not occur. The raw material pellets are preferably sufficiently vacuum-dried.

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

  In this invention, it is preferable that the extending | stretching temperature at the time of extending | stretching a polyester film shall be more than the secondary transition point (Tg) of polyester. It is preferable to stretch 1 to 8 times, particularly 2 to 6 times in the longitudinal and lateral directions.

  It is preferable that the said polyester film is 12-50 micrometers in thickness, More preferably, it is 15-38 micrometers, More preferably, it is 19 micrometers-33 micrometers. If the thickness of the film is 12 μm or more, it is preferable that there is no risk of deformation due to heat during film production, a release layer processing step, or molding of a ceramic green sheet. On the other hand, if the thickness of the film is 50 μm or less, the amount of the film discarded after use is not extremely increased, which is preferable in reducing the environmental load.

  The biaxially oriented polyester film substrate may be a single layer or a multilayer of two or more layers, but preferably has a surface layer A substantially free of particles on at least one side. 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 that can contain particles on the opposite surface of the surface layer A that does not substantially contain particles. As a laminated structure, when the layer on the side where the release layer is applied is the surface layer A, the opposite layer is the surface layer B, and the other core layer is the layer C, the layer structure in the thickness direction is the release layer / Examples thereof include a laminated structure such as A / B or release layer / A / C / B. Of course, the layer C may have a plurality of layer configurations. Further, the surface layer B can contain no particles. In that case, it is preferable to provide a coat layer 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 of the present invention, it is preferable that the surface layer A that forms the surface on which the release layer is applied does not substantially contain particles. At this time, the area 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 are less likely to occur during molding of the laminated ultra-thin ceramic green sheet. Although it can be said that the region surface average roughness (Sa) of the surface layer A is preferably as small as possible, it may be 0.1 nm or more. Here, when an anchor coat layer, which will be described later, is provided on the surface layer A, it is preferable that the coat layer does not substantially contain particles, and the area surface average roughness (Sa) after coating layer lamination is in the above range. It is preferable to enter. In the present invention, “substantially free of particles” means, for example, in the case of inorganic particles, when inorganic elements are quantified by fluorescent X-ray analysis, 50 ppm or less, preferably 10 ppm or less, most preferably the detection limit or less. Content. This means that even if particles are not actively added to the film, contaminants derived from foreign substances, raw resin, or dirt adhering to the lines and equipment in the film manufacturing process may be peeled off and mixed into the film. Because there is.

  In the polyester film substrate of the present invention, the surface layer B that forms the surface opposite to the surface on which the release layer is applied preferably contains particles from the viewpoint of the slipperiness of the film and the ease of air removal. It is preferable to use silica particles and / or calcium carbonate particles. The contained particle content is preferably 5000 to 15000 ppm in total in the surface layer B. At this time, it is preferable that the area | region surface average roughness (Sa) of the film of the surface layer B is the range of 1-40 nm. More preferably, it is the range of 5-35 nm. When the total of silica particles and / or calcium carbonate particles is 5000 ppm or more and Sa is 1 nm or more, when the film is rolled up, air can be released uniformly, and the winding shape is good and the flatness is good. This is suitable for the production of an ultrathin layer ceramic green sheet. In addition, when the total of silica particles and / or calcium carbonate particles is 15000 ppm or less and Sa is 40 nm or less, the lubricant is less likely to agglomerate and coarse protrusions cannot be formed, so the quality is stable when manufacturing ultra-thin ceramic green sheets. It is preferable.

  As particles contained in the surface layer B, inactive inorganic particles and / or heat-resistant organic particles other than silica and / or calcium carbonate can be used. Silica particles and / or calcium carbonate particles are more preferably used from the viewpoint of transparency and cost, but other inorganic particles that can be used include alumina-silica composite oxide particles, hydroxyapatite particles, and the like. 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 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. If the average particle diameter of the particles is 0.1 μm or more, the slipperiness of the release film is good, which is preferable. Moreover, if an average particle diameter is 2.0 micrometers or less, there is no possibility that a pinhole may generate | occur | produce in the ceramic green sheet by the coarse particle of a mold release layer surface, and it is preferable.

  The surface layer B may contain two or more kinds of particles having different materials. Moreover, you may contain the same kind of particle | grains from which an average particle diameter differs. In the present invention, the method for measuring the average particle size of the particles employs a method of observing 100 cross-sectional particles with a scanning electron microscope and observing 100 particles and setting the average value to the average particle size. it can. The shape of the particle is not particularly limited as long as it satisfies the object of the present invention, and spherical particles and non-spherical particles can be used. The particle diameter of the irregular shaped 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 circumference ratio (π) and calculating the square root and doubling it.

When the surface layer B does not contain particles, it is preferable that the surface layer B has a slipperiness with a coat layer containing particles. Although this coating layer is not specifically limited, It is preferable to provide with the in-line coating applied during film forming of a polyester film. When the surface layer B does not contain particles, and the surface layer B has a coat layer containing particles, the surface of the coat layer is a region for the same reason as the surface average roughness (Sa) of the surface layer B described above. The surface average roughness (Sa) is preferably in the range of 1 to 40 nm. More preferably, it is the range of 5-35 nm.

  From the viewpoint of reducing pinholes, it is preferable not to use a regenerated raw material or the like for the surface layer A, which is a layer on the side where the release layer is provided, from the viewpoint of reducing pinholes.

  The thickness ratio of the surface layer A, which is the layer on the side where the release layer is provided, is preferably 20% to 50% of the total thickness of the 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 is easy to satisfy the above range, which is preferable. When the thickness is 50% or less of the total thickness of the base film, the use ratio of the recycled raw material in the surface layer B can be increased, and the environmental load is reduced, which is preferable.

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

  In addition, the 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 or the like to be applied later or to prevent charging. A coating layer may be provided, and corona treatment or the like may be performed. When a coating layer is provided on the surface layer A, it is preferable that the coating layer does not substantially contain particles.

(Release layer)
The release layer in the present invention preferably contains at least a binder component and a silicone release agent. In addition to the resin and compound, other components can be added as long as the effects of the present invention are not impaired.

(Binder component)
The binder component contained in the release layer of the present invention is not particularly limited, but a component that can be cross-linked to increase the cross-linking density of the release layer and improve the durability and solvent resistance of the release layer is cross-linked. It is preferable that Therefore, it is preferable that the binder component is obtained by reacting a resin having a reactive functional group and a crosslinking agent. Further, it is also preferable that either a reactive functional group or a crosslinking agent is self-crosslinked alone. However, in the present invention, an embodiment in which the binder component is composed only of a resin having a reactive functional group or a crosslinking agent is not excluded.

  Although it does not specifically limit as resin which has a reactive functional group, A polyester-type resin, a polyacrylic-type resin, a polyurethane-type resin, a polyolefin-type resin etc. can be used conveniently. These resins preferably have at least one kind selected from a carboxyl group, a hydroxyl group, an epoxy, an amino group and the like as a reactive functional group.

  The resin having a reactive functional group preferably has a long-chain alkyl group and / or a silicone skeleton as part of the resin skeleton. By having a low surface free energy site such as a long-chain alkyl group and / or a silicone skeleton in a part of the resin skeleton, the compatibility between the silicone-based mold release agent described below and the binder component is increased, and aggregation occurs during drying. Is preferred because it is less likely to occur and the smoothness is improved.

  Specific examples of the reactive functional group-containing resin having a long-chain alkyl group in the resin skeleton include alkyd resins or acrylic resins having a long-chain alkyl group in the side chain. As the long-chain alkyl group to be used, a linear alkyl group having 6 to 20 carbon atoms is preferable. By having the above-mentioned carbon number, the surface free energy of the obtained resin can be reduced, and the compatibility with the silicone-based release agent is improved, which is preferable.

  In the case of an alkyd resin having a long-chain alkyl group in the side chain, an acid having a long-chain alkyl group (for example, octylic acid or stearyl acid) is mixed with a polybasic acid such as phthalic acid, and a polyhydric alcohol component ( Pentaerythritol, diethylene glycol, etc.) and can be obtained by a dehydration condensation reaction.

  The acrylic resin having a long-chain alkyl group in the side chain is preferably obtained by copolymerizing two or more kinds of acrylic monomers. The monomer to be copolymerized preferably includes a monomer having a long-chain alkyl group (for example, lauryl acrylate, stearyl acrylate, isodecyl acrylate, etc.), and a monomer having a hydroxy group as a reactive functional group (for example, hydroxyethyl) Acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, etc.). In addition to the above, other known monomers such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, hexanediol dimethacrylate, and butanediol diacrylate can also be included in order to impart Tg adjustment, crosslinkability, reactivity, and the like of the polymer obtained. .

  The content of the monomer having a long-chain alkyl group in the obtained acrylic resin is preferably 1 mol% or more and 50 mol% or less with respect to all monomers. 1 mol% or more is preferred because of the effect of reducing the surface free energy. When the amount is 50 mol% or less, the monomer having a reactive functional group is relatively high, so that the crosslinking density of the resin is high, which is preferable.

  Specific examples of the reactive functional group-containing resin having a silicone skeleton in the resin skeleton include alkyd resins or acrylic resins having a polydimethylsiloxane skeleton in the side chain. Specific examples of commercially available products include Cymac (registered trademark) US350, US352 (manufactured by Toa Gosei Co., Ltd., reactive functional group: carboxyl group), Cymac (registered trademark) US270 (manufactured by Toagosei Co., Ltd., reactive functional group: hydroxyl group) )and so on.

(Crosslinking agent)
It is also preferable that the binder component contains a crosslinking agent. Although it does not specifically limit as a crosslinking agent, A melamine type | system | group, an isocyanate type, a carbodiimide type | system | group, an oxazoline type | system | group, an epoxy type, etc. can be used, You may use it in combination of 1 type or 2 types or more. Particularly preferred is a crosslinking agent that reacts with a reactive functional group introduced into the binder component.

  The crosslinking agent used in the present invention is preferably a melamine compound from the viewpoint of reactivity. The use of a melamine compound is preferable because even a thin film having a release layer thickness of 0.2 μm or less can be cured quickly and the crosslinking density becomes high.

  As the melamine compound used in the present invention, a general compound can be used and is not particularly limited. The melamine compound is obtained by condensing melamine and formaldehyde, and each has a triazine ring, a methylol group and / or an alkoxymethyl group in one molecule. It is preferable to have one or more. Specifically, a compound obtained by subjecting a methylolmelamine derivative obtained by condensing melamine and formaldehyde to etherification by dehydration condensation reaction of methyl alcohol, ethyl alcohol, isopropyl alcohol, butyl alcohol or the like as a lower alcohol is preferable. Examples of methylolated melamine derivatives include monomethylol melamine, dimethylol melamine, trimethylol melamine, tetramethylol melamine, pentamethylol melamine, and hexamethylol melamine. One type or two or more types may be used.

  As the melamine compound, it is preferable to use hexamethylol melamine having many crosslinking points in one molecule, hexamethoxymethylol melamine, or the like because the crosslinking density of the binder component can be increased. From the viewpoint of reactivity, hexamethoxymethyl methylol melamine obtained by dehydration condensation with methyl alcohol is particularly preferred when an ether compound obtained by dehydration condensation reaction using an alcohol as a methylol melamine derivative is used.

  The amount of the crosslinking agent contained in the binder component in the present invention is preferably 15% by mass or more, more preferably 30% by mass or more, and further preferably 50% by mass with respect to the resin having a reactive functional group. It is. Moreover, when a crosslinking agent can self-condense and can form a resin film, a binder component may be comprised only with a crosslinking agent. It is preferable to contain 15% by mass or more of a crosslinking agent because the crosslinking density of the release layer can be increased and the solvent resistance and elastic modulus can be improved.

(catalyst)
In the release layer in the present invention, a catalyst may be used for curing the crosslinking agent. When a melamine compound is used, it is preferable to use an acid catalyst, and although not particularly limited, carboxylic acid, metal salt, phosphate ester, and sulfonic acid compounds can be preferably used. Further, a block type catalyst in which an acid site is blocked can also be used. In particular, paratoluenesulfonic acid can be suitably used from the viewpoint of reactivity. When using an isocyanate compound, a general thing can be used and organic tin, an amine compound, a trialkylphosphine compound, etc. can be used conveniently.

  It is preferable that the addition amount of a catalyst is 0.1-40 mass% with respect to the crosslinking agent contained in a mold release layer. More preferably, it is 0.5-30 mass%. More preferably, it is 0.5-20 mass%. When the content is 0.1% by mass or more, the curing reaction easily proceeds, which is preferable. On the other hand, if it is 40% by mass or less, the acid catalyst is not likely to migrate to the ceramic green sheet to be molded, which is preferable because there is no risk of adverse effects.

(Silicone mold release agent)
The silicone release agent used in the release layer in the present invention is a compound having a silicone structure in the molecule and is not particularly limited as long as the effects of the present invention can be obtained, but polyorganosiloxane and the like are preferably used. Can be used. Among polyorganosiloxanes, polydimethylsiloxane (abbreviation, PDMS) can be preferably used, and those having a functional group in part of the polydimethylsiloxane are also preferred. Having a functional group is preferable because intermolecular interaction such as hydrogen bonding with the binder resin is likely to occur and migration to the ceramic green sheet is difficult.

  Although it does not specifically limit as a functional group introduce | transduced into polydimethylsiloxane, A reactive functional group or a non-reactive functional group may be sufficient. In addition, the functional group may be introduced at one end of polydimethylsiloxane, or both ends or side chains may be used. Moreover, the position to be introduced may be one or plural.

  As a reactive functional group introduced into polydimethylsiloxane, an amino group, an epoxy group, a hydroxyl group, a mercapto group, a carboxyl group, a methacryl group, an acrylic group, or the like can be used. As the non-reactive functional group, a polyether group, an aralkyl group, a fluoroalkyl group, a long chain alkyl group, an ester group, an amide group, a phenyl group, or the like can be used. Although not particularly restricted by theory, among the above, those having an epoxy group, a carboxyl group, a polyether group, a methacryl group, an acrylic group, and an ester group are preferable.

  The functional group introduced into polydimethylsiloxane is more preferably one that does not react with the binder component. For example, polydimethylsiloxane modified with a hydroxyl group that reacts with a melamine resin reacts with melamine in the drying step, and therefore, it may be difficult to orient on the surface of the release layer and release properties may be difficult. For this reason, it is necessary to increase the amount of addition in order to provide sufficient release properties. In this case, however, the elastic modulus of the release layer may be reduced, and the release layer may be easily deformed.

  As the functional group to be introduced into the polydimethylsiloxane, as a functional group that does not react with the binder resin for the reasons described above, is easy to be oriented on the surface of the release layer, and has little transferability to the ceramic green sheet, a polyether group, An ester group is preferred, and a polyether group is particularly preferred.

  The silicone mold release agent used in the present invention preferably has a molecular weight of 40000 or less. More preferably, it is 30000 or less. When the molecular weight is 40,000 or less, the silicone release agent is easily segregated on the surface of the release layer, and the releasability is good.

  The release layer in the present invention preferably contains a silicone compound in an amount of 0.1% by mass or more and 20% by mass or less based on the solid content of the entire release layer. More preferably, they are 0.1 mass% or more and 10 mass% or less, More preferably, they are 0.1 mass% or more and 5 mass% or less. When the content is 0.1% by mass or more, the releasability is improved and the peelability of the ceramic green sheet is improved, which is preferable. On the other hand, when it is 20% by mass or less, there is little transfer of the silicone compound to the ceramic green sheet at the time of peeling. At this time, the solid content of the entire release layer is considered to be a substantially total value of the solid contents of the binder component and the release agent because the solvent and the catalyst are partially evaporated in the drying process or are originally very small. It does not matter.

  The release layer in the present invention can contain particles having a particle size of 1 μm or less, but it is preferable not to contain particles that form protrusions from the viewpoint of suppressing pinholes in the ceramic green sheet.

  In the release layer of the present invention, an additive such as an adhesion improver or an antistatic agent may be added as long as the effect of the present invention is not impaired. In order to improve the adhesion to the substrate, it is also preferable that the polyester film surface is subjected to pretreatment such as anchor coating, corona treatment, plasma treatment, atmospheric pressure plasma treatment, etc. before providing the release coating layer.

  In the present invention, the thickness of the release layer is preferably 0.2 μm or less. More preferably, it is 0.01-0.2 micrometer, More preferably, it is 0.02-0.15 micrometer, It is more preferable if it is 0.02-0.09 micrometer. When the thickness of the release layer is 0.01 μm or more, it is preferable that peeling performance is easily obtained. When the thickness is 0.2 μm or less, the curing time of the release layer can be shortened, so that the planarity of the release film can be maintained and uneven thickness of the ceramic green sheet can be suppressed. Moreover, since the curl of the obtained film also lessens that it is 0.2 micrometer or less, since a shaping | molding precision improves at the time of ceramic green sheet shaping | molding, it is preferable.

Surface free energy of the release layer surface of the release film of the present invention is preferably 18 mJ / ^{m 2} or more 35 mJ / ^{m 2} or less. More preferably, 20 mJ / ^{m 2} or more 30 mJ / ^{m 2} or less, further preferably 21 mJ / ^{m 2} or more 28 mJ / ^{m 2} or less. When it is 18 mJ / m ² or more, repelling is difficult to occur when the ceramic slurry is applied, which is preferable. Moreover, it is preferable that it is 35 mJ / m ² or less because there is no fear that the releasability of the ceramic green sheet is lowered. By setting it as the said range, there is no repellency at the time of coating, and the release film excellent in the release property can be provided.

The release film of the present invention preferably has a peeling force of 0.5 mN / mm ² or more and 3 mN / mm ² or less when peeling the ceramic green sheet. More preferably, it is 0.8 mN / mm ² or more and 2.5 mN / mm ² or less. More preferably, it is 1.0 mN / mm ² or more and 1.8 mN / mm ² or less. When the peeling force is 0.5 mN / mm ² or more, the peeling force is not too light, and the ceramic green sheet is preferably not lifted during transportation. When the peeling force is 3 mN / mm ² or less, the ceramic green sheet is preferably not damaged during peeling.

  The release film of the present invention preferably has less curl. Specifically, the curl after heating at 100 ° C. for 15 minutes without applying tension to the film is preferably 2 mm or less, more preferably 1 mm or less. Of course, it is also preferable not to curl at all. It is preferable that the thickness is 2 mm or less because when the ceramic green sheet is molded and an electrode is printed, curling is less and printing accuracy can be improved.

  The release layer surface of the release film of the present invention is desirably flat so as not to cause defects in the ceramic green sheet applied and molded thereon, and the area surface average roughness (Sa) is 1.5 nm or less. Preferably, it is 1.2 nm or less, and more preferably 1.0 nm or less. Further, the maximum protrusion height (P) on the surface of the release layer is preferably 50 nm or less, more preferably 40 nm or less, and still more preferably 30 nm or less. If the area surface average roughness (Sa) is 1.5 nm or less and the maximum protrusion height (P) is 50 nm or less, there is no occurrence of defects such as pinholes during the formation of the ceramic green sheet, and the yield is favorable. The smaller the surface average surface roughness (Sa), the better. However, it may be 0.1 nm or more, or 0.3 nm or more. It can be said that the smaller the maximum protrusion height (P) is, the better, but it may be 1 nm or more, or 3 nm or more.

  Since the release film of the present invention uses a highly flattened base film, the release layer surface is smooth even if the thickness of the release layer is 0.2 μm or even less than 0.09 μm. Therefore, the amount of solvent and resin used can be reduced, and a release film for molding an ultra-thin ceramic green sheet can be produced at low cost, which is environmentally friendly.

  In order to set the maximum protrusion height (P) on the surface of the release layer of the release film of the present invention to 50 nm or less and the arithmetic average roughness (Sa) to 1.5 nm or less, a coating solution for the release layer is applied. It is preferable to suppress aggregation of the silicone-based release agent and binder component before drying. Therefore, the target ultra-smooth release layer surface can be obtained by performing the time from coating to drying under certain conditions as described in the production method described later.

(Manufacturing method of release film)
The release film manufacturing method of the present invention includes a coating step in which a coating solution in which at least a binder component and a silicone-based release agent are dissolved or dispersed in a solvent is laminated on at least one surface of a polyester film of a substrate by coating or the like; After the application, it is preferable to use a method in which the release layer is laminated through an initial drying step for mainly removing the solvent and a heat curing step for mainly curing the binder resin. The surface of the polyester film on the side where the release layer is provided is preferably a surface layer A that does not substantially contain particles, and there is another coat layer between the surface layer A and the release layer. It doesn't matter.

(Coating process)
The solvent for dissolving or dispersing the binder resin and the silicone-based release agent is not particularly limited, but an organic solvent is preferably used. The use of an organic solvent is preferable because the surface tension of the coating liquid can be lowered, so that repelling and the like hardly occur after coating, and the smoothness of the release layer surface can be kept high.

  It does not specifically limit as an organic solvent used for the manufacturing method of the release film of this invention, A well-known thing can be used. As the solvent, aromatic hydrocarbons such as benzene, toluene and xylene, fatty acid hydrocarbons such as cyclohexane, n-hexane and n-heptane, halogenated hydrocarbons such as perchloroethylene, ethyl acetate, methyl ethyl ketone, methyl Examples include isobutyl ketone. In consideration of applicability when applied to the surface of the substrate film, a mixed solvent of toluene and methyl ethyl ketone is preferable although not limited.

In the present invention, the coating liquid used for coating for forming the release layer is not particularly limited, but it is preferable to include two or more kinds of organic solvents having different boiling points. The at least one organic solvent preferably has a boiling point of 100 ° C. or higher. By adding a solvent having a boiling point of 100 ° C. or more, bumping at the time of drying can be prevented, the coating film can be leveled, and the smoothness of the coating film surface after drying can be improved. As the addition amount, it is preferable to add about 10-50 mass% with respect to the whole coating liquid. Examples of the solvent having a boiling point of 100 ° C. or higher include toluene, xylene, heoctane, cyclohexanone, methyl isobutyl ketone, and n-propyl acetate.

  In the present invention, the surface tension (20 ° C.) of the coating liquid when the coating liquid for forming the release layer is applied is not particularly limited, but is preferably 30 mN / m or less. By making the surface tension as described above, the paintability after coating can be improved, and the unevenness of the coating film surface after drying can be reduced. In order to lower the surface tension of the coating liquid, it is preferable to use an organic solvent having a low surface tension as the organic solvent for forming the coating liquid. The surface tension (20 ° C.) of at least one organic solvent is preferably 26 mN / m or less, more preferably 23 mN / m or less. It is preferable to include an organic solvent having a surface tension (20 ° C.) of 26 mN / m or less because appearance defects such as repelling can be reduced during coating. As the addition amount, it is preferable to add 20 mass% or more with respect to the whole coating liquid.

  The solid content concentration of the release agent contained in the coating liquid is preferably 0.1% by mass or more and 10% by mass or less, and more preferably 0.2% by mass or more and 8% by mass or less. It is preferable that the solid content concentration is 0.1% by mass or more because drying after coating is quick, so that aggregation of components in the release agent hardly occurs. On the other hand, when the solid content concentration is 10% by mass or less, since the viscosity of the coating liquid is low and the leveling property is good, the planarity after coating can be improved, which is preferable. The viscosity of the coating solution is preferably 1 mPa · s or more and 100 mPa · s or less, more preferably 2 mPa · s or more and 10 mPa · s or less. It is preferable to adjust the solid content concentration, the organic solvent, etc. so as to be in this range.

  In this invention, it is preferable to filter the coating liquid for mold release layer formation before application | coating. The filtration method is not particularly limited and a known method can be used, but it is preferable to use a surface type, depth type, or adsorption type cartridge filter. The use of a cartridge type filter is preferable because it can be used when the coating liquid is continuously fed from the tank to the coating section, so that the productivity can be efficiently filtered. As the filtration accuracy of the filter, it is preferable to use a filter that removes 99% or more of a 1 μm size, and more preferably a filter that can filter 99% or more of a 0.5 μm size. By using the above-mentioned filtration accuracy, foreign matter mixed in the release agent can be removed, and the foreign matter adhering to the release film of the ceramic green sheet molding release film of the present invention can be greatly reduced. it can. Therefore, the defects of the molded ceramic green sheet using the release film of the present invention are reduced, and the defect rate of the ceramic capacitor can be reduced.

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

  The coating liquid film thickness (Wet film thickness) at the time of application is preferably 1 μm or more and 10 μm or less. If it is thicker than 1 μm, the coating is stable, and defects such as cissing and streaks are less likely to occur. Moreover, if it is 10 micrometers or less, drying is quick and it is preferable that the component contained in a mold release layer does not aggregate easily.

(Drying process)
Examples of the method of applying the coating liquid on the substrate film and drying it include known hot air drying and heat drying with an infrared heater, but hot air drying with a high drying speed is preferred. The drying furnace can be divided into a constant rate drying step in the initial stage of drying (hereinafter referred to as an initial drying step) and a step in which reduction rate drying and resin curing proceed (hereinafter referred to as a heat curing step). The initial drying step and the heat curing step may be continuous or discontinuous, but being continuous is preferable because of good productivity. It is preferable to distinguish each process by dividing | segmenting the zone of a drying furnace. The number of zones in each process is not limited as long as it is one or more.

  In the manufacturing method of the release film of this invention, it is preferable to put into a drying furnace within 1.5 second after application | coating, More preferably, it is within 1.0 second, and within 0.8 second is further more preferable. Prevents deterioration of the smoothness of the release layer surface due to aggregation because it can be dried before aggregation of the components contained in the release layer occurs by putting it in a drying oven within 1.5 seconds after coating. Is preferable. It is preferable that the time from application to the drying furnace is short, and there is no particular lower limit, but it may be 0.05 seconds or longer, or 0.1 seconds or longer.

  The initial drying step is not particularly limited, and a known drying furnace can be used. The drying furnace method can be either the roll support method or the floating method, but the roll support method has a wider range of adjustment of the airflow during drying, so the airflow etc. can be adjusted according to the type of release layer. This is preferable because it is possible.

  The temperature in the initial drying step is preferably 60 ° C. or higher and 140 ° C. or lower, more preferably 70 ° C. or higher and 130 ° C. or lower, and further preferably 80 ° C. or higher and 120 ° C. or lower. It is preferable to set the temperature to 60 ° C. or higher and 140 ° C. or lower because the amount of organic solvent contained in the release layer after coating can be effectively dried without poor planarity due to heat.

  The time for passing through the initial drying step is preferably 1.0 seconds or more and 3.0 seconds or less, more preferably 1.0 seconds or more and 2.5 seconds or less, 1.2 seconds or more, 2.5 seconds or less. More preferred is less than a second. It is preferable that the time is 1.0 second or longer because the organic solvent contained in the release layer after coating can be sufficiently dried. Moreover, it is preferable that it is 3.0 seconds or less that aggregation of components in the release layer hardly occurs. By adjusting the solid content concentration of the coating liquid, the organic solvent type, and the like so that it can be dried in the above-described time, even if a coating liquid that easily aggregates is used, deterioration of smoothness due to aggregation can be suppressed.

  The amount of the organic solvent contained in the release layer after passing through the initial drying step is preferably 5% by mass or less, more preferably 2% by mass or less. It is preferable that the amount of the organic solvent is 5% by mass or less because deterioration in appearance due to bumping or the like can be prevented even when heated in the heating step. The amount of the organic solvent in the release layer can be measured by sampling the film after the initial drying step and measuring it by gas chromatography, thermogravimetric analysis, or the like, but can be estimated by using drying simulation. The direction obtained from the simulation is preferable because the measurement can be performed without stopping the process. The simulation is not particularly limited, but known simulation software can be used.

(Heat curing process)
The release film of the present invention preferably undergoes a heat curing step after the initial drying step. The heat curing step is not particularly limited, and a known drying furnace can be used. The drying furnace method may be either a roll support method or a floating method. The heat curing step may be a step continuous with the initial drying step or a discontinuous step, but is preferably a continuous step from the viewpoint of productivity.

  The temperature in the heat curing step is preferably 80 ° C. or higher and 180 ° C. or lower, more preferably 90 ° C. or higher and 160 ° C. or lower, and most preferably 90 ° C. or higher and 140 ° C. or lower. When the temperature is 180 ° C. or lower, the flatness of the film is maintained, and the possibility of causing uneven thickness of the ceramic green sheet is small. When the temperature is 140 ° C. or lower, the film can be processed without impairing the flatness of the film, and the possibility of causing uneven thickness of the ceramic green sheet is further reduced, which is particularly preferable. When the temperature is 80 ° C. or higher, a thermosetting resin is preferable because curing proceeds sufficiently.

  The time for passing through the heat curing step is preferably 2 seconds to 30 seconds, more preferably 2 seconds to 20 seconds. When the passage time is 2 seconds or more, the curing of the thermosetting resin proceeds, which is preferable. Moreover, it is preferable that it is 30 seconds or less because the flatness of the film by heat does not deteriorate.

  At the end of the heat curing step, it is preferable to set the hot air temperature to be equal to or lower than the glass transition temperature of the base film and to set the actual temperature of the base film to be equal to or lower than the glass transition temperature in a flat state. If the actual temperature of the base film exits the drying furnace with the glass transition temperature or higher, slippage will be poor when it comes into contact with the roll surface, causing not only scratches but also curls and the like. is there.

  The release film of the present invention is preferably wound into a roll after passing through the heat curing step. After passing through the heat curing step, the time until winding up into a roll is preferably 2 seconds or longer, more preferably 3 seconds or longer. If it is 2 seconds or more, the release film whose temperature has been raised in the heat curing step is cooled and wound on a roll, which is preferable because the flatness is not impaired.

  In the release film of the present invention and the method for producing the release film, various treatments may be performed after the heat-curing step and before winding up into a roll shape, such as static elimination treatment, corona treatment, plasma treatment, ultraviolet irradiation treatment, electron beam. Irradiation treatment or the like can be performed.

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

  The release film for producing a ceramic green sheet of the present invention is used for producing such a multilayer ceramic capacitor. For example, it is manufactured as follows. First, the release film of the present invention is used as a carrier film, and a ceramic slurry for constituting a ceramic body is applied and dried. A conductive layer for forming the first or second internal electrode is printed on the coated and dried ceramic green sheet. A ceramic green sheet, a ceramic green sheet printed with a conductive layer for constituting the first internal electrode, and a ceramic green sheet printed with a conductive layer for constituting the second internal electrode are appropriately laminated and pressed. Thus, a mother laminate is obtained. The mother laminated body is divided into a plurality of parts to produce a raw ceramic body. A ceramic body is obtained by firing a raw ceramic body. Thereafter, the multilayer ceramic capacitor can be completed by forming the first and second external electrodes.

  Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples. The characteristic values used in the present invention were evaluated using the following methods.

(Surface roughness)
It is the value measured on condition of the following using a non-contact surface shape measurement system (Ryoka System make, VertScan R550H-M100). The average value of the area surface roughness (Sa) was an average value of 5 measurements, and the maximum protrusion height (P) 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: 10 times ・ 0.5 × Tube lens ・ Measurement area: 936 μm × 702 μm
(Analysis conditions)
・ Surface correction: 4th order correction ・ Interpolation processing: Complete interpolation

(Release layer thickness)
The cut release film was embedded in a resin and was cut into ultrathin sections using an ultramicrotome. Thereafter, observation was performed directly at a magnification of 20,000 times using a JEM2100 transmission electron microscope manufactured by JEOL, and the film thickness of the release layer was measured from the observed TEM image.

(Surface free energy)
Using a contact angle meter (manufactured by Kyowa Interface Science Co., Ltd .: fully automatic contact angle meter DM-701) under conditions of 25 ° C. and 50% RH, water (droplet amount 1.8 μL) is used on the release surface of the release film. Then, droplets of diiodomethane (appropriate amount of liquid 0.9 μL) and ethylene glycol (appropriate amount of liquid 0.9 μL) were prepared and their contact angles were measured. As the contact angle, the contact angle 10 seconds after each solution was dropped onto the release film was employed. The contact angle data of water, diiodomethane, and ethylene glycol obtained by the above method was calculated from the “Kitazaki-Hataba” theory to determine the surface free energy dispersion component γsd, polar component γsp, and hydrogen bond component γsh of the release film, The total of each component was defined as the surface free energy γs. This calculation was performed using calculation software in the contact angle meter software (FAMAS).

(Surface tension of coating liquid)
The surface tension of the coating liquid was measured by the Wilhelmy method using a platinum plate under a condition of 20 ° C. using a surface tension meter (manufactured by Kyowa Interface Science Co., Ltd .: high-functional surface tension meter DY-500). Three measurements were taken and the average value was adopted.

(Viscosity of coating liquid)
The viscosity of the coating solution was measured under a 20 ° C. condition using a rotary viscometer (manufactured by Toki Sangyo Co., Ltd .: TVB-15M). When measuring a low viscosity liquid of 10 mPa · s or less, the measurement was performed using an optional low viscosity adapter. Three measurements were taken and the average value was adopted.

(Coating property evaluation of ceramic slurry)
The composition consisting of the following materials was stirred and mixed, and dispersed for 30 minutes using a bead mill using glass beads having a diameter of 0.5 mm as a dispersion medium to obtain 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 (Esreck (registered trademark) BM-S manufactured by Sekisui Chemical Co., Ltd.)
DOP (dioctyl phthalate) 1.8 parts by mass Next, the obtained release film sample was coated on the release surface using an applicator so that the dried slurry would be 1 μm, dried at 90 ° C. for 1 minute, and then The coating property was evaluated according to the criteria. ○: There is no repelling and the entire surface can be applied.
Δ: Slight repellency at the coating end, but almost all surfaces are coated.
X: There are many repellents and it cannot coat.

(Ceramic green sheet pinhole evaluation)
A ceramic green sheet having a thickness of 1 μm was molded on the release surface of the release film in the same manner as in the evaluation of the coating property of the ceramic slurry.
Next, using an applicator, the slurry after drying was applied to the release surface of the obtained release film sample to a thickness of 1 μm, dried at 90 ° C. for 1 minute, the release film was peeled off, and the ceramic green sheet was removed. Obtained.
In the central region in the film width direction of the obtained ceramic green sheet, light was applied from the opposite side of the ceramic slurry coating surface within a range of 25 cm ² , and the occurrence of pinholes through which light was transmitted was observed. Visual judgment was made.
○: No occurrence of pinholes △: Almost no occurrence of pinholes ×: Many occurrences of pinholes

(Evaluation of peelability of ceramic green sheets)
The composition consisting of the following materials was stirred and mixed, and dispersed for 60 minutes using a bead mill using glass beads having a diameter of 0.5 mm as a dispersion medium to obtain a ceramic slurry. Toluene 38.3 parts by mass Ethanol 38.3 parts by mass Barium titanate (HPBT-1 manufactured by Fuji Titanium Co., Ltd.) 64.8 parts by mass Polyvinyl butyral 6.5 parts by mass (Sekisui Chemical Co., Ltd. ESREC (registered trademark) BM-S)
DOP (dioctyl phthalate) 3.3 parts by mass Next, the obtained release film sample was applied to the release surface using an applicator so that the dried slurry had a thickness of 10 μm, and dried at 90 ° C. for 1 minute to produce ceramic. A green sheet was molded on the release film. The obtained release film with ceramic green sheet was neutralized using a static eliminator (SJ-F020, manufactured by Keyence Corporation), and then peeled at a width of 30 mm at a peeling angle of 90 degrees and a peeling speed of 10 m / min. The stress applied at the time of peeling was measured and taken as the peeling force.

(Curl evaluation of release film)
The release film sample was cut into a size of 10 cm × 10 cm, and heat-treated at 100 ° C. for 15 minutes in a hot air oven so that no tension was applied to the release film. Then, after taking out from the oven and cooling to room temperature, the release film sample was placed on the glass plate so that the release surface was up, and the height of the part floating from the glass plate was measured. At this time, the height of the most floating part from the glass plate was taken as the measured value. Curl properties were evaluated according to the following criteria.
○: Curling is 1 mm or less, and it is hardly curled.
(Triangle | delta): The curl is larger than 1 mm and is 2 mm or less, and a little curl was seen.
X: The curl was curled larger than 2 mm.

(Preparation of polyethylene terephthalate pellets (PET (I)))
As the esterification reaction apparatus, a continuous esterification reaction apparatus comprising a three-stage complete mixing tank having a stirrer, a partial condenser, a raw material charging port and a product outlet was used. TPA (terephthalic acid) is 2 tons / hour, EG (ethylene glycol) is 2 moles per mole of TPA, antimony trioxide is made into an amount that makes Sb atoms 160 ppm with respect to the produced PET, and these slurries are esterified. Was continuously supplied to the first esterification reactor of the chemical reaction apparatus, and allowed to react at 255 ° C. at an average residence time of 4 hours at normal pressure. 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 is distilled off from the first esterification reaction can in the second esterification reaction can. EG solution containing 8 mass% of EG with respect to the generated PET, and further containing EG solution containing magnesium acetate tetrahydrate in an amount of 65 ppm of Mg atoms relative to the generated PET, and 40 ppm of P atoms relative to the generated PET An EG solution containing a quantity of TMPA (trimethyl phosphate) was added and reacted at 260 ° C. at normal pressure for an average residence time of 1 hour. 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 ) using a high pressure disperser (manufactured by Nippon Seiki Co., Ltd.). An average particle of 0.2 mass% of porous colloidal silica having an average particle diameter of 0.9 μm and an ammonium salt of polyacrylic acid adhered to 1 mass% of calcium carbonate, which was dispersed at an average number of treatments of 5 passes under the pressure of While adding 0.4% by mass of synthetic calcium carbonate having a diameter of 0.6 μm as an EG slurry of 10%, the reaction was carried out at 260 ° C. at an average residence time of 0.5 hours at normal pressure. 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 sintered with a stainless steel fiber having a 95% cut diameter of 20 μm. After filtering with a filter, ultrafiltration was performed and extruded into water, and after cooling, it was cut into chips to obtain PET chips with an intrinsic viscosity of 0.60 dl / g (hereinafter referred to as PET (I)). . The lubricant content in the PET chip was 0.6% by mass.

(Preparation of polyethylene terephthalate pellets (PET (II)))
On the other hand, in the production of the 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 abbreviated as PET (II)).

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

(Manufacture of laminated film X1)
These PET chips were dried, melted at 285 ° C., melted at 290 ° C. with a separate melt extruder extruder, sintered with stainless steel fibers having a 95% cut diameter of 15 μm, and a 95% cut diameter Two-stage filtration of a 15 μm stainless steel particle-sintered filter is performed and merged in the feed block, PET (I) is surface layer B (reverse mold release side layer), and PET (II) is surface Laminated so as to be layer A (release surface side layer), extruded (casting) into a sheet at a speed of 45 m / min, electrostatically adhered and cooled on a casting drum at 30 ° C. by electrostatic adhesion method, An unstretched polyethylene terephthalate sheet having an intrinsic viscosity of 0.59 dl / g was obtained. The layer ratio is calculated by calculating the discharge amount of each extruder PET (I) / PET (II
) = 60% / 40%. Next, this unstretched sheet was heated with 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, the film was guided to a tenter and stretched 4.2 times in the transverse direction at 140 ° C. Subsequently, it heat-processed at 210 degreeC in the heat setting zone. Thereafter, a relaxation treatment of 2.3% was performed at 170 ° C. in the transverse direction to obtain a biaxially stretched polyethylene terephthalate film X1 having a thickness of 31 μm. Sa of surface layer A of the obtained film X1 was 2 nm, and Sa of surface layer B was 28 nm.

(Manufacture of laminated film X2)
The layer configuration and stretching conditions similar to those of the laminated film X1 were not changed, but the thickness was adjusted by changing the speed during casting to obtain a biaxially stretched polyethylene terephthalate film X2 having a thickness of 25 μm. Sa of surface layer A of the obtained film X2 was 3 nm, and Sa of 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 coating layer containing particles is provided on the surface layer B side by in-line coating. Sa of surface layer A of laminated film X3 was 1 nm, and Sa of surface layer B was 2 nm.

(Laminated film X4)
As the laminated film X4, E5101 (Toyobo Ester (registered trademark) film, manufactured by Toyobo Co., Ltd.) having a thickness of 25 μm was used. E5101 has a structure in which particles are contained in the surface layers A and B of the film. Sa of the surface layer A of the laminated film X4 was 24 nm, and Sa of the surface layer B was 24 nm.

(Manufacture of laminated film X5)
PET (III) is surface layer B (reverse release surface side layer), PET (II) is surface layer A (release surface side layer)
The layer ratio is calculated by calculating the discharge amount of each extruder. PET (III) / (II) = 80%
A biaxially stretched polyethylene terephthalate film X5 having a thickness of 31 μm was obtained in the same manner as the laminated film X1 except that the thickness was changed to / 20%. Sa of surface layer A of the obtained film X5 was 2 nm, and Sa of surface layer B was 30 nm.

(Resin Solution A) Long-chain alkyl group-containing acrylic polyol 20% by mole of stearyl (meth) acrylate, 40% by mole of hydroxyethyl (meth) acrylate, 40% by mole of methyl (meth) acrylate and mixed to obtain a solid content It diluted with toluene so that a density | concentration might be 40 mass%, 0.5 mol% of azobisisobutyronitrile was added and copolymerized under nitrogen stream, and the resin solution A was obtained. The weight average molecular weight of the polymer obtained at this time was 30000.

Example 1
After coating the coating liquid 1 having the following composition on the surface layer A of the laminated film X1 through a filter capable of removing 99% or more of foreign matters of 0.5 μm or more, the coating film thickness (wet film thickness) is 5 μm using a reverse gravure. After coating, it was adjusted to enter the initial drying furnace in 0.5 seconds. After drying at 100 ° C. for 2 seconds in an initial drying furnace, it was continuously put into a heat curing step and heated at 130 ° C. for 7 seconds. After the heat curing step, a release film for producing an ultrathin layer ceramic green sheet was obtained in 8 seconds after winding. Table 3 shows the results of measuring the film thickness, surface roughness, surface free energy, and curl of the obtained release film. Moreover, when a ceramic slurry was applied to the obtained release film and coating properties, peelability and pinholes were evaluated, good evaluation results were obtained.
(Coating liquid 1) Solid content: 1.0% by mass, surface tension: 27 mN / m, viscosity: 5 mPa · s
Methyl ethyl ketone 57.93 parts by mass Toluene 40.00 parts by mass Resin solution A 1.75 parts by mass (long-chain alkyl group-containing acrylic polyol, solid content 40%)
0.25 parts by mass of cross-linking agent (hexamethoxymethylol melamine, solid content 100%)
0.05 part by mass of silicone release agent (polyether-modified polydimethylsiloxane, TSF4446, solid content 100%, manufactured by Momentive)
Acid catalyst (para-toluenesulfonic acid) 0.02 parts by mass

(Examples 2 to 4, Comparative Example 1)
A release film for producing an ultrathin layer ceramic green sheet was prepared in the same manner as in Example 1 except that the composition of the coating liquid 1 was changed to the ratio shown in Table 1. When the obtained release film was evaluated, the release force was good and good results were obtained for the examples containing the silicone release agent, but in Comparative Example 1 containing no silicone release agent, the release force was obtained. When the ceramic green sheet was peeled from the release film, defects such as pinholes were likely to occur.

(Examples 5-7, Comparative Example 2)
A release film for producing an ultra-thin ceramic green sheet was prepared in the same manner as in Example 1 except that the resin ratio of the coating liquid 1 was maintained and the solid content was changed to that shown in Table 1 to change the thickness of the release layer. .
When the obtained release film was evaluated, the examples in which the thickness of the release layer was 0.2 μm or less were good results without curling, but Comparative Example 2 in which the thickness of the release layer was 0.5 μm. The result was that the curl deteriorated greatly.

(Example 8)
A release film for producing an ultrathin ceramic green sheet was prepared in the same manner as in Example 1 except that the coating liquid 1 was changed to the coating liquid 8.
(Coating fluid 8)
Methyl ethyl ketone 57.35 parts by mass Toluene 40.00 parts by mass Cymac (registered trademark) US270 2.33 parts by mass (silicone group-containing acrylic polyol, manufactured by Toagosei Co., Ltd., solid content 30%)
0.25 parts by mass of cross-linking agent (hexamethoxymethylol melamine, solid content 100%)
0.05 part by mass of silicone release agent (polyether-modified polydimethylsiloxane, TSF4446, solid content 100%, manufactured by Momentive)
Acid catalyst (para-toluenesulfonic acid) 0.02 parts by mass

Example 9
A release film for producing an ultrathin layer ceramic green sheet was prepared in the same manner as in Example 1 except that the coating liquid 1 was changed to the coating liquid 9.
(Coating fluid 9)
Methyl ethyl ketone 58.03 parts by mass Toluene 40.00 parts by mass Tesfine 305 1.90 parts by mass (Long-chain alkyl group-containing aminoalkyd resin, manufactured by Hitachi Chemical Co., Ltd., solid content 50%)
0.05 part by mass of silicone release agent (polyether-modified polydimethylsiloxane, TSF4446, solid content 100%, manufactured by Momentive)
Acid catalyst (para-toluenesulfonic acid) 0.02 parts by mass

(Example 10)
A release film for producing an ultrathin layer ceramic green sheet was prepared in the same manner as in Example 1 except that the coating liquid 1 was changed to the coating liquid 10.
(Coating solution 10)
Methyl ethyl ketone 57.55 parts by mass Toluene 40.00 parts by mass Tesfine 322 2.38 parts by mass (Long-chain alkyl group-containing aminoacrylic resin, Hitachi Chemical Co., Ltd., solid content 40%)
0.05 part by mass of silicone release agent (polyether-modified polydimethylsiloxane, TSF4446, solid content 100%, manufactured by Momentive)
Acid catalyst (para-toluenesulfonic acid) 0.02 parts by mass

(Example 11)
An ultrathin layer ceramic green sheet in the same manner as in Example 1 except that the coating solution 11 in which the resin solution A of the coating solution 1 is changed to 6AN-5000 (an acrylic resin not containing a long chain alkyl group) of the coating solution 10 is used. A release film for production was prepared.
(Coating solution 11)
Methyl ethyl ketone 57.93 parts by mass Toluene 40.00 parts by mass 6AN-5000 1.75 parts by mass (acrylic polyol, manufactured by Taisei Fine Chemical Co., Ltd., solid content 40%)
0.25 parts by mass of cross-linking agent (hexamethoxymethylol melamine, solid content 100%)
0.05 part by mass of silicone release agent (polyether-modified polydimethylsiloxane, TSF4446, solid content 100%, manufactured by Momentive)
Acid catalyst (para-toluenesulfonic acid) 0.02 parts by mass

(Example 12)
A release film for producing an ultrathin layer ceramic green sheet was prepared in the same manner as in Example 1 except that the coating liquid 1 was changed to the coating liquid 12.
(Coating fluid 12)
Methyl ethyl ketone 58.95 parts by mass Toluene 40.00 parts by mass Hexamethoxymethylolmelamine 0.95 parts by mass (100% solids)
0.05 part by mass of silicone release agent (polyether-modified polydimethylsiloxane, TSF4446, solid content 100%, manufactured by Momentive Performance Materials)
0.05 parts by mass of acid catalyst (paratoluenesulfonic acid)

  Even if the binder component was changed as in Examples 8 to 12, good results were obtained. Even when a resin containing a long-chain alkyl group or a silicone skeleton in the binder component was processed under the same conditions, the surface protrusions tended to be lower.

(Example 13)
A release film for producing an ultrathin layer ceramic green sheet was prepared in the same manner as in Example 1 except that the coating liquid 1 was changed to the coating liquid 13.
(Coating fluid 13)
Methyl ethyl ketone 57.78 parts by mass Toluene 40.00 parts by mass Resin solution A 1.75 parts by mass (long-chain alkyl group-containing acrylic polyol, solid content 40%)
0.25 parts by mass of cross-linking agent (hexamethoxymethylol melamine, solid content 100%)
0.20 parts by mass of silicone release agent (polyester-modified polydimethylsiloxane, BYK-310, solid content 25%, manufactured by Big Chemie Japan)
Acid catalyst (para-toluenesulfonic acid) 0.02 parts by mass

(Example 14)
A release film for producing an ultrathin layer ceramic green sheet was prepared in the same manner as in Example 1 except that the coating liquid 1 was changed to the coating liquid 14.
(Coating solution 14)
Methyl ethyl ketone 57.93 parts by mass Toluene 40.00 parts by mass Resin solution A 1.75 parts by mass (long-chain alkyl group-containing acrylic polyol, solid content 40%)
0.25 parts by mass of cross-linking agent (hexamethoxymethylol melamine, solid content 100%)
0.05 part by mass of silicone release agent (carboxyl-modified polydimethylsiloxane, X22-3710, solid content 100%, manufactured by Shin-Etsu Chemical Co., Ltd.)
Acid catalyst (para-toluenesulfonic acid) 0.02 parts by mass

(Example 15)
A release film for producing an ultrathin layer ceramic green sheet was prepared in the same manner as in Example 1 except that the coating liquid 1 was changed to the coating liquid 15.
(Coating fluid 15)
Methyl ethyl ketone 57.78 parts by mass Toluene 40.00 parts by mass Resin solution A 1.75 parts by mass (long-chain alkyl group-containing acrylic polyol, solid content 40%)
0.25 parts by mass of cross-linking agent (hexamethoxymethylol melamine, solid content 100%)
0.20 parts by mass of a silicone release agent (polyester-modified hydroxyl group-containing polydimethylsiloxane, BYK-370, solid content 25%, manufactured by Big Chemie Japan)
Acid catalyst (para-toluenesulfonic acid) 0.02 parts by mass

  In Examples 13 to 15 in which the type of the silicone release agent was changed, good evaluation results were obtained, but the ones that did not contain a hydroxyl group that reacts with the crosslinking agent (melamine in this example) were the same. There was a tendency for the peelability to improve under the conditions.

(Examples 16 to 18, Comparative Example 3)
A release film for producing an ultrathin ceramic green sheet was prepared in the same manner as in Example 1 except that the base film in Example 1 was changed to the base film shown in Table 1.
When the obtained release film was evaluated, in Examples 1 to 15 and 16 to 18 using X1, X2, X3, and X5 not containing particles in the surface layer A of the base film, Sa on the release layer surface was used. , P was low and the pinhole evaluation was good, whereas in Comparative Example 3 using X4 containing particles in the surface layer A of the base film, both Sa and P on the surface of the release layer were high, and the pinhole The result was that the evaluation deteriorated.

(Examples 19 to 22, Comparative Examples 4 and 5)
Regarding the production conditions of Example 1, ultrathinness was performed in the same manner as in Example 1 except that the time after application to the time of entering the initial drying furnace, or the temperature and passage time of the initial drying furnace were changed to the conditions shown in Table 2. A release film for producing a multilayer ceramic green sheet was prepared.

(Comparative Example 6)
A release film for producing an ultrathin ceramic green sheet was produced in the same manner as in Example 11 except that the production conditions of Example 11 were changed to the conditions shown in Table 2.

  When the obtained film was evaluated, the time taken to enter the initial drying furnace after coating was 1.5 seconds or less, and in the examples where the passage time of the initial drying furnace was 1.0 second or more and 3.0 seconds or less, the mold release was performed. The surface roughness Sa of the layer surface and the maximum protrusion height P were low, and the pinhole evaluation was good, whereas in the comparative example excluded from the above conditions, the release layer was agglomerated and the surface roughness of the release layer was This is a result of increasing Sa and maximum protrusion height P.

  According to the present invention, the release layer of the release film for producing ceramic green sheets includes at least a binder component and a silicone release agent, thereby suppressing deterioration of surface roughness due to aggregation of the above components during drying. However, it has become possible to provide a release film having high smoothness and excellent releasability, and an efficient method for producing the release film.

Claims (5)

  A polyester film is used as a base material, and the base material has a surface layer A substantially free of particles on at least one side, and is released directly on the surface of the surface layer A on at least one side or via another layer. A release film in which layers are laminated, and the curl after heating at 100 ° C. for 15 minutes without applying tension is 2 mm or less, and the release layer contains a binder component and a silicone release agent, A release film for producing a ceramic green sheet, wherein the maximum protrusion height (P) on the surface of the release layer is 50 nm or less.   The release film for producing a ceramic green sheet according to claim 1, wherein the binder component contained in the release layer contains a resin having a long-chain alkyl group and / or a silicone skeleton.   The release agent for producing a ceramic green sheet according to claim 1 or 2, wherein the silicone-based release agent has a polyether moiety and is contained in a release layer in an amount of 0.1 to 20% by mass. Mold film.   It is a manufacturing method of the ceramic green sheet which shape | molds a ceramic green sheet using the release film for ceramic green sheet manufacture in any one of Claims 1-3, Comprising: The shape | molded ceramic green sheet is 0.2 micrometer ~ 1. A method for producing a ceramic green sheet having a thickness of 0.0 μm.   5. A method for producing a ceramic capacitor, wherein the method for producing a ceramic green sheet according to claim 4 is adopted.