JP6977748B2 - Release film for manufacturing ceramic green sheets - Google Patents

Description

The present invention relates to a release film for manufacturing a ceramic green sheet, and more specifically, it is possible to suppress the occurrence of process defects due to pinholes and uneven thickness during the manufacture of an ultrathin ceramic green sheet, and the ceramic is ceramic when the ceramic green sheet is peeled off. The present invention relates to an ultra-thin layer ceramic green sheet manufacturing release film that can be peeled off without damaging the ceramic green sheet by minimizing the force applied to the green sheet.

Conventionally, a release film having a polyester film as a base material and a release layer laminated on the polyester film has been used for molding ceramic green sheets such as laminated ceramic capacitors and ceramic substrates. In recent years, as the size and capacity of multilayer ceramic capacitors have increased, the thickness of ceramic green sheets has also tended to decrease. The ceramic green sheet is molded by applying a slurry containing a ceramic component such as barium titanate and a binder resin to a release film and drying it. A laminated ceramic capacitor is manufactured by printing an electrode on a molded ceramic green sheet, peeling it from a release film, laminating and pressing the ceramic green sheet, firing, and applying an external electrode. When a ceramic green sheet is molded on the surface of the release layer of a polyester film, there is a problem that minute protrusions on the surface of the release layer affect the molded ceramic green sheet, and defects such as cissing and pinholes are likely to occur. there were. Therefore, various methods for realizing a release layer surface having excellent flatness have been developed (see, for example, Patent Document 1).

However, in recent years, further thinning of the ceramic green sheet has progressed, and a ceramic green sheet having a thickness of 1.0 μm or less, more specifically 0.2 μm to 1.0 μm, has been required. Therefore, since the strength of the ceramic green sheet is lowered, it is required not only to smooth the surface of the release layer but also to reduce and make the peeling force when the ceramic green sheet is peeled from the release film low and uniform. It has become. That is, it is becoming more important to minimize the force applied to the ceramic green sheet when peeling the ceramic green sheet from the release film so as not to damage the ceramic green sheet.

In recent years, it has been disclosed that a thin ceramic green sheet can be peeled off with an appropriate peeling force without causing defects by forming a release layer in which a composition containing a melamine resin as a main component is heat-cured. (See, for example, Patent Document 2). Further, the weight average molecular weight of the melamine resin in the range of 1,000 to 10,000 is used, by increasing the amount of methylol groups _(CH 2 -OH), discloses that can suppress the occurrence of curling.

The weight average molecular weight of the melamine compound can also be expressed by the weight average degree of polymerization. When the weight average molecular weight of the melamine resin is 1000 or more, it means that the ratio of polynuclear bodies such as dimers, trimers and multimers in which melamine compounds are condensed is large, and the degree of weight average polymerization is high. It means that the value of is large.

However, if the release layer uses a composition containing a melamine resin having a large weight average molecular weight as described above, the reactivity of the melamine resin tends to be insufficient, and an ultrathin ceramic green sheet, specifically The peelability when peeling an ultrathin layer product of 1 μm or less was insufficient, and there was a possibility that a defect would occur in the ceramic green sheet after peeling. Further, in recent years, the film thickness tends to be reduced from the viewpoint of reducing the environmental load and cost. Therefore, if the release film uses a composition containing a melamine resin having a large weight average molecular weight as the release layer, the reactivity of the melamine resin is insufficient, and therefore it is necessary to apply a relatively large amount of heat during processing. There was still a concern that the flatness and winding appearance would deteriorate during processing, and that curling would occur. Furthermore, since there are restrictions on the processing speed, there has been a demand for a mold release layer that can be processed more economically.

Japanese Unexamined Patent Publication No. 2000-117899 Japanese Unexamined Patent Publication No. 2017-007226

The present invention has been made in the background of the problems of the prior art. That is, the production of a ceramic green sheet capable of molding a ceramic green sheet having a low peeling force and uniform thickness and having few defects even in an ultrathin layer product having a thickness of 1 μm or less while maintaining high smoothness on the surface of the release layer of the release film. It is intended to provide a release film.

As a result of diligent studies to solve the above problems, the present inventors have provided a release layer directly on at least one side or via another layer using a polyester film, and at least a melamine compound and a carboxyl group are provided in the release layer. By curing the composition containing the polyorganosiloxane containing the above and setting the weight average degree of polymerization of the melamine compound to 2.0 or less, the force applied to the ceramic green sheet when the ceramic green sheet is peeled off is minimized. It has been found that it is possible to provide a release film for producing a ceramic green sheet having excellent peelability, which can be peeled off without damaging the ceramic green sheet.

That is, the present invention has the following configuration.
1. 1. A biaxially oriented polyester film is used as a base material, and the base material has a surface layer A having substantially no inorganic particles on at least one side thereof, and a layer directly or another layer is formed on the surface of the surface layer A on at least one side. A release layer is laminated therethrough, and the release layer is formed by curing a composition containing at least a release agent and a melamine compound, and the release agent is a polyorganosiloxane containing a carboxyl group. A ceramic green sheet having a weight average polymerization degree of the melamine compound of 2.0 or less and a content of the melamine compound of 80% by mass or more with respect to the solid content of the release layer forming composition. Release film for manufacturing.
2. 2. One side of the substrate has a surface layer A that does not substantially contain inorganic particles, the surface layer B has a surface layer B on the opposite side of the substrate from the surface layer A, and the surface layer B contains particles. The release film for producing a ceramic green sheet according to the first aspect, wherein at least a part of the particles is silica particles and / or calcium carbonate particles, and the total content of the particles with respect to the mass of the surface layer B is 5000 to 15000 ppm.
3. 3. The release film for producing a ceramic green sheet according to the first or second above, wherein the region surface average roughness (Sa) of the release layer is 7 nm or less, and the maximum protrusion height (P) is 100 nm or less.
4. A method for manufacturing a ceramic green sheet by molding a ceramic green sheet using the release film for manufacturing a ceramic green sheet according to any one of the first to third, wherein the molded ceramic green sheet has a thickness of 0.2 μm or more. A method for manufacturing a ceramic green sheet having a thickness of 1.0 μm.
5. A method for manufacturing a ceramic capacitor, which employs the method for manufacturing a ceramic green sheet according to the fourth item.

The release film for manufacturing an ultrathin ceramic green sheet of the present invention has a smooth surface on the release layer, and has pinholes and pinholes during the production of a ceramic green sheet as compared with the conventional release film for manufacturing a ceramic green sheet. The occurrence of process defects due to uneven thickness can be suppressed, the force applied to the ceramic green sheet when the ceramic green sheet is peeled off can be reduced as much as possible, and the ceramic green sheet can be peeled off without damaging it, resulting in over 0.2 to 1.0 μm. It is possible to efficiently manufacture a thin-layer ceramic green sheet.

Hereinafter, the present invention will be described in detail.

The release film for producing a ceramic green sheet of the present invention comprises a composition containing at least a melamine-based compound and a polyorganosiloxane containing a carboxyl group on at least one side of a polyester film as a base material, either directly or via another layer. It is preferable that the cured release layer is laminated. Then, one side of the polyester film as a base material has a surface layer A that does not substantially contain inorganic particles, and the composition is cured on the surface layer A directly or via another layer. It is preferable that the release layer is laminated.

(Polyester film)
The polyester constituting the polyester film used as the base material in the present invention is not particularly limited, and a film-molded polyester usually generally used as a base material for a release film can be used, but it is preferable. It is preferably a crystalline linear saturated polyester composed of an aromatic dibasic acid component and a diol component, for example, polyethylene terephthalate, polyethylene-2,6-naphthalate, polybutylene terephthalate, polytrimethylene terephthalate or resins thereof. A copolymer containing a constituent component as a main component is more preferable, and a polyester film formed from polyethylene terephthalate is particularly preferable. The repeating unit of ethylene terephthalate is preferably 90 mol% or more, more preferably 95 mol% or more, and other dicarboxylic acid components and diol components may be copolymerized in a small amount, but from the viewpoint of cost. , Preferably made only from terephthalic acid and ethylene glycol. Further, known additives such as antioxidants, light stabilizers, ultraviolet absorbers, crystallization agents and the like may be added as long as the effects of the film of the present invention are not impaired. The polyester film is preferably a biaxially oriented polyester film because of its high bidirectional elastic modulus and the like.

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

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

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

The thickness of the polyester film is preferably 12 to 50 μm, more preferably 15 to 38 μm, and even more preferably 19 μm to 33 μm. When the thickness of the film is 12 μm or more, it is preferable because there is no possibility of deformation due to heat during film production, a process of processing a release layer, and molding of a ceramic green sheet or the like. On the other hand, when the thickness of the film is 50 μm or less, the amount of the film discarded after use does not become extremely large, which is preferable in reducing the environmental load.

The polyester film base material may be a single layer or a multilayer of two or more layers, but it is preferable that the surface layer A having substantially no inorganic particles on at least one surface thereof. In the case of a laminated polyester film having a multilayer structure of two or more layers, it is preferable to have a surface layer B capable of containing particles or the like on the opposite surface of the surface layer A which does not substantially contain inorganic particles. As for the laminated structure, if the layer on the side to which the release layer is applied is the surface layer A, the layer on the opposite surface thereof is the surface layer B, and the core layer other than these is the layer C, the layer structure in the thickness direction is the release layer / A laminated structure such as A / B or a release layer / A / C / B can be mentioned. As a matter of course, the layer C may have a plurality of layer configurations. Further, the surface layer B may not contain particles. In that case, it is preferable to provide a coat layer containing particles and a binder on the surface layer B in order to impart slipperiness for winding the film into a roll.

In the polyester film base material of the present invention, it is preferable that the surface layer A forming the surface to which the release layer is applied does not substantially contain inorganic particles. At this time, the region surface average roughness (Sa) of the surface layer A is preferably 7 nm or less. When Sa is 7 nm or less, pinholes and the like are less likely to occur during molding of the ultrathin layer ceramic green sheet to be laminated, which is preferable. It can be said that the smaller the region surface average roughness (Sa) of the surface layer A is, the more preferable it is, but it may be 0.1 nm or more. Here, when an anchor coat layer or the like, which will be described later, is provided on the surface layer A, it is preferable that the coat layer does not substantially contain inorganic particles, and the region surface average roughness (Sa) after laminating the coat layer is in the above range. It is preferable to enter. In the present invention, "substantially free of inorganic particles" means a content of 50 ppm or less, preferably 10 ppm or less, and most preferably detection limit or less when the inorganic element is quantified by the optical X-ray analysis. do. This means that even if inorganic particles are not actively added to the film, contamination components derived from foreign substances and stains attached to raw material resins or lines and devices in the film manufacturing process are peeled off and mixed into the film. This is because there are cases.

In the polyester film base material of the present invention, the surface layer B forming the opposite surface to the surface to which the release layer is applied preferably contains particles from the viewpoint of the slipperiness of the film and the ease with which air can escape. It is preferable to use silica particles and / or calcium carbonate particles. The particle content is preferably 5,000 to 15,000 ppm in total in the surface layer B. At this time, the region surface average roughness (Sa) of the film of the surface layer B is preferably in the range of 1 to 40 nm. More preferably, it is in the range of 5 to 35 nm. When the total amount of silica particles and / or calcium carbonate particles is 5000 ppm or more and Sa is 1 nm or more, air can be uniformly released when the film is rolled into a roll shape, and the rolled shape is good and the flatness is good. , Suitable for the production of ultra-thin layer ceramic green sheet. Further, when the total amount of silica particles and / or calcium carbonate particles is 15,000 ppm or less and Sa is 40 nm or less, the lubricant is less likely to aggregate and coarse protrusions cannot be formed, so that the quality is stable during the production of an ultrathin ceramic green sheet. It is preferable.

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

The average particle size of the particles added to the surface layer B is preferably 0.1 μm or more and 2.0 μm or less, and particularly preferably 0.5 μm or more and 1.0 μm or less. When the average particle size of the particles is 0.1 μm or more, the slipperiness of the release film is good, which is preferable. Further, when the average particle size is 2.0 μm or less, pinholes are not likely to occur in the ceramic green sheet due to the coarse particles on the surface of the release layer, which is preferable.

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

When the surface layer B does not contain particles, it is preferable to provide slipperiness with a coat layer containing particles on the surface layer B. The coating layer is not particularly limited, but is preferably provided by an in-line coating applied during the formation of the polyester film. When the surface layer B does not contain particles and has a coat layer containing particles on the surface layer B, the surface of the coat layer has a region for the same reason as the above-mentioned region surface average roughness (Sa) of the surface layer B. The surface average roughness (Sa) is preferably in the range of 1 to 40 nm. More preferably, it is in the range of 5 to 35 nm.

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

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

Further, from the viewpoint of economic efficiency, 50 to 90% by mass of film waste or recycled raw material for PET bottles can be used for the layers other than the surface layer A (surface layer B or the above-mentioned 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 size, and the region surface average roughness (Sa) satisfy the above ranges.

Further, a film before or after uniaxial stretching in the film forming process on the surface of the surface layer A and / or the surface layer B in order to improve the adhesion of the release layer to be applied later and prevent charging. A coat layer may be provided on the surface, or a corona treatment or the like may be applied.

(Structure of release layer)
It is preferable that the release layer in the present invention is formed by curing a composition containing at least a melamine-based compound and a polyorganosiloxane containing a carboxyl group. In addition to the resin and additives, other components can be added as long as the effects of the present invention are not impaired.

As the melamine-based compound used for the release layer in the present invention, a general compound can be used and is not particularly limited, but it is obtained by condensing melamine and formaldehyde, and a triazine ring and a methylol group and / or an alkoxy are contained in one molecule. It is preferable to have one or more methyl groups each. Specifically, a compound obtained by dehydrating and condensing a methylalcohol melamine derivative obtained by condensing melamine and formaldehyde with methyl alcohol, ethyl alcohol, isopropyl alcohol, butyl alcohol and the like as lower alcohols to etherify them is preferable. Examples of the methylolated melamine derivative include monomethylol melamine, dimethylol melamine, trimethylol melamine, tetramethylol melamine, pentamethylol melamine, and hexamethylol melamine. One type may be used or two or more types may be used.

The release layer in the present invention preferably has a high crosslink density and a high elastic modulus in order to suppress the deformation of the release layer that occurs at the time of peeling and to make the peeling force low and uniform. Therefore, it is preferable to use hexamethylol melamine or hexaalkoxymethyl melamine having more cross-linking points in one molecule, but hexaalkoxymethyl melamine having better reactivity is more preferable, and hexamethoxymethyl melamine is particularly preferable. At this time, the hexamethylol melamine _{is one in which X is a methylol group (−CH 2-} OH) in the following formula (a). Hexaalkoxymethylmelamine is obtained by subjecting a methylol melamine derivative to a dehydration condensation reaction using an alcohol, and X is (-CH _2- OR, R is an alkyl group having 1 to 4 carbon atoms). The hexamethoxymethylmelamine are those wherein X is _(-CH 2 -OMe).

The Xs in the above (a) may be the same or different. Further, the above Rs may be the same or different from each other. Further, X may be (−H).

The melamine compound used for the release layer in the present invention preferably has a weight average molecular weight of 250 or more and 1000 or less. More preferably, the weight average molecular weight is 250 or more and 900 or less, and more preferably 300 or more and 800 or less. When the weight average molecular weight is 1000 or less, the cross-linking reaction easily proceeds, a film having a higher cross-linking density can be formed, and the peeling force can be reduced, which is preferable. When the weight average molecular weight is 250 or more, the crosslink density does not become excessively high and the curl does not deteriorate, which is preferable. The weight average molecular weight in the present specification is a value in terms of standard polystyrene measured by a gel permeation chromatography (GPC) method.

The fact that the weight average molecular weight of the melamine-based compound is 250 to 1000 means that the melamine-based compound used in the present invention contains a large amount of mononuclear compounds. Since the mononuclear body has more cross-linking points and is excellent in reactivity than the polynuclear body formed by condensing two or more melamine derivatives, it can be a release layer having a high cross-linking density and excellent peelability. The larger the content of the mononuclear body, the more preferable, and it is most preferable to use a melamine-based compound composed of only the mononuclear body.

The weight average molecular weight can also be expressed by the weight average degree of polymerization. The weight average degree of polymerization of the melamine-based compound used is preferably 2.0 or less, more preferably 1.5 or less, and the smaller the weight average polymerization degree, the more preferably it can be used. When the weight average degree of polymerization is 2.0 or less, the content of the mononuclear body contained in the melamine compound increases, and the release layer having excellent reactivity and peelability can be obtained, which is preferable. The weight average degree of polymerization in the present specification is a value calculated based on the weight average molecular weight obtained by gel permeation chromatography in terms of standard polystyrene.

Melamine-based compounds may contain imino groups (-NH _2- ) or polynuclear compounds in the process of their synthesis. Even if these melamine derivatives are mixed, if the weight average molecular weight (that is, the weight average degree of polymerization) of the melamine compound is within the above range, the reactivity is excellent and each of them can be suitably used.

The release layer in the present invention preferably contains a melamine compound in an amount of 80% by mass or more and 99.9% by mass or less, more preferably 90% by mass or more, based on the solid content of the release layer forming composition. It is 99.9% by mass or less, more preferably 95% by mass or more and 99.9% by mass or less. By containing 80% by mass or more of the melamine-based compound, the release layer can obtain a high cross-linking density by self-crosslinking of the melamine-based compound, and the deformation of the release layer at the time of peeling can be suppressed. At this time, the solid content of the release layer forming composition is substantially the total value of the solid content of the melamine-based compound and the release agent because the solvent and the acid catalyst partially evaporate during the drying process. It can be regarded as.

It is preferable to add an acid catalyst to the release layer in the present invention in order to promote the cross-linking reaction of the melamine compound, and it is possible to add an acid catalyst to the release layer forming composition, apply it, and cure it. preferable. As the acid catalyst to be used, it is preferable to use a sulfonic acid-based catalyst.

As the sulfonic acid-based catalyst, for example, p-toluene sulfonic acid, xylene sulfonic acid, cumene sulfonic acid, dodecylbenzene sulfonic acid, dinonylnaphthalene sulfonic acid, trifluoromethanesulfonic acid and the like can be preferably used, but the reaction From the viewpoint of sex, p-toluenesulfonic acid can be particularly preferably used.

As the sulfonic acid-based catalyst used in the present invention, commercially available ones can also be used. Examples of commercially available products include dryer (registered trademark) 900 (p-toluenesulfonic acid, manufactured by Hitachi Kasei), NACURE (registered trademark) DNNDSA series (dinonylnaphthalenedisulfonic acid, manufactured by Kusumoto Kasei), and DNNSA series (registered trademark). Dinonylnaphthalene (mono) sulfonic acid, manufactured by Kusumoto Kasei Co., Ltd.), DDBSA series (dodecylbenzene sulfonic acid, manufactured by Kusumoto Kasei Co., Ltd.), p-TSA series (p-toluenesulfonic acid, manufactured by Kusumoto Kasei Co., Ltd.), etc. Be done.

Since the sulfonic acid-based catalyst has higher acidity and excellent reactivity than other acid catalysts such as carboxylic acid-based catalysts, the release layer can be processed at a lower temperature. Therefore, it is preferable because it is possible to suppress deterioration of the flatness of the film due to heat during processing and deterioration of the rolled appearance.

The amount of the acid catalyst added is preferably 0.1 to 10% by mass with respect to the melamine-based compound contained in the release layer. More preferably, it is 0.5 to 8% by mass. More preferably, it is 0.5 to 7% by mass. When it is 0.1% by mass or more, the curing reaction tends to proceed, which is preferable. On the other hand, when it is 10% by mass or less, there is no possibility that the acid catalyst is transferred to the ceramic green sheet to be molded, and there is no possibility of adverse effects, which is preferable.

As the release agent (additive for improving the release property of the release layer) used for the release layer in the present invention, polyorganosiloxane containing a carboxyl group may be used from the viewpoint of achieving both releasability and suppression of transfer amount. preferable. Among the polyorganosiloxane structures, polyorganosiloxane containing a carboxyl group having a polydimethylsiloxane structure (abbreviation, PDMS) can be preferably used.

Since the release agent polyorganosiloxane contains a carboxyl group, the release agent does not show a strong interaction with the melamine-based compound in the drying process, and easily orients to the surface of the release layer, resulting in good release. can get. Therefore, it is preferable to use a polyorganosiloxane containing a carboxyl group because the release property can be satisfied even if the amount of the release agent added is small. Further, it is preferable that the polyorganosiloxane, which is a release agent, contains a carboxyl group because it shows a weak interaction with a melamine-based compound, and therefore it is difficult to transfer to a ceramic green sheet.

The carboxyl group may be introduced at one end of the polyorganosiloxane, or may be at both ends or a side chain, but the one introduced at one end is preferable because it has excellent peelability. Further, the number of positions to be introduced may be one or a plurality.

The carboxyl group-modified polyorganosiloxane may be one in which a carboxyl group is directly bonded to the silicon atom of the polyorganosiloxane, but one in which a carboxyl group is bonded to the polyorganosiloxane via an alkyl group or an aryl group. There may be. However, those in which a carboxyl group is bonded to polyorganosiloxane via an organic group having a repeating structure such as polyether, polyester, and polyurethane are not so preferable.

As the functional group to be introduced into the polyorganosiloxane which is a release agent, one molecule may have another functional group other than the carboxyl group, but only the carboxyl group is preferable. If a functional group other than the carboxyl group is contained, the intermolecular interaction with the melamine compound may be increased more than necessary and it may be difficult to orient the release layer on the surface, which is not preferable.

Polyorganosiloxane modified with a hydroxyl group that has a strong interaction with the melamine compound reacts rapidly with the melamine compound in the drying step, so it is difficult to align with the surface of the release layer and it is difficult to develop releasability. There is. Therefore, it is necessary to increase the amount added in order to have sufficient releasability, but in that case, the elastic modulus of the release layer may decrease, the release layer may be easily deformed at the time of peeling, and the release force may increase. be. Further, when the amount of polyorganosiloxane added is increased, the amount transferred to the ceramic green sheet tends to increase, which is not preferable.

The carboxyl group-containing polyorganosiloxane used in the present invention preferably has a molecular weight of 40,000 or less. More preferably, it is 30,000 or less. When the molecular weight is 40,000 or less, the polyorganosiloxane containing a carboxyl group is easily segregated on the surface of the release layer and has good peelability, which is preferable.

As described above, the polyorganosiloxane containing a carboxyl group is more preferably a polydimethylsiloxane containing a carboxyl group. Examples of the polydimethylsiloxane containing a carboxyl group include X22-3701E (side chain carboxyl-modified polydimethylsiloxane, manufactured by Shin-Etsu Chemical Industry Co., Ltd.), X22-3710 (one-ended carboxyl-modified polydimethylsiloxane, manufactured by Shin-Etsu Chemical Industry Co., Ltd.), and X22. -162C (both-terminal carboxyl-modified polydimethylsiloxane, manufactured by Shinetsu Chemical Industry Co., Ltd.), BY16-750 (both-terminal carboxyl-modified polydimethylsiloxane, manufactured by Toray Dow Corning), BY16-880 (side chain carboxyl-modified polydimethylsiloxane, manufactured by Toray) Dow Corning), Magnasoft 800L (both-terminal carboxyl-modified polydimethylsiloxane, Momentive) and the like can be used.

The carboxyl group-containing polydimethylsiloxane in the present invention may be an acrylic resin in which polydimethylsiloxane is introduced into a side chain of a carboxyl group-containing acrylic main chain. As the acrylic resin in which polydimethylsiloxane is introduced into the side chain of the acrylic main chain containing a carboxyl group, Cymac (registered trademark) US-350, US-352, US-380 (all manufactured by Toagosei Co., Ltd.) and the like are used. Can be used. Further, it may be an acrylic resin in which polydimethylsiloxane is introduced into a side chain of an acrylic main chain containing a carboxyl group and a hydroxyl group in one molecule. As acrylic resins in which polydimethylsiloxane is introduced into the side chain of an acrylic main chain containing a carboxyl group and a hydroxyl group in one molecule, Cymac® US-450 and US-480 (all manufactured by Toagosei Co., Ltd.) ) Etc. can be used.

The release layer in the present invention preferably contains a release agent in an amount of 0.1% by mass or more and 20% by mass or less with respect to the solid content of the composition for forming the release layer. More preferably, it is 0.1% by mass or more and 10% by mass or less, and further preferably 0.1% by mass or more and 5% by mass or less. When it 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, the elastic modulus of the entire release layer does not decrease too much, and it is possible to suppress the deformation of the release layer and the increase in the release force when the ceramic green sheet is peeled off, which is preferable. Further, when it is 20% by mass or less, it is preferable from the viewpoint that the transfer amount of the release agent does not become too high. At this time, the solid content of the release layer forming composition is substantially the total value of the solid content of the melamine-based compound and the release agent because the solvent and the acid catalyst partially evaporate during the drying process. It can be regarded as.

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

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

(Characteristics of release layer)
In the present invention, the thickness of the release layer may be set according to the purpose of use, and is not particularly limited, but preferably, the weight of the release coating layer after curing is in the range of 0.01 to 2.0 μm. It is better, more preferably 0.01 to 1.7 μm, still more preferably 0.01 to 1.5 μm, and even more preferably 0.02 to 1.3 μm. When the thickness of the release layer is 0.01 μm or more, peeling performance can be obtained, which is preferable. Further, when it is 2.0 μm or less, the curing time can be shortened, the flatness of the release film can be maintained, and the uneven thickness of the ceramic green sheet can be suppressed, which is preferable.

The release layer surface of the release film of the present invention is preferably flat so as not to cause defects in the ceramic green sheet coated and molded on the release layer surface, and the region surface average roughness (Sa) is 7 nm or less and the maximum. The protrusion height (P) is preferably 100 nm or less. Further, it is more preferable that the region surface average roughness is 5 nm or less and the maximum protrusion height is 80 nm or less. When the region surface roughness is 7 nm or less and the maximum protrusion height is 100 nm or less, defects such as pinholes do not occur when the ceramic green sheet is formed, and the yield is good, which is preferable. It can be said that the smaller the region surface average roughness (Sa) is, the more preferable it is, but 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 more preferable it is, 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 has a thickness of less than 0.5 μm, and even if the thickness of the release layer is thinner than 0.2 μm, the surface of the release layer can be obtained. Can be smoothed. Therefore, even in the release layer using a highly reactive melamine compound, the generation of curl can be suppressed. In addition, the amount of solvent and resin used can be reduced, which is environmentally friendly, and a release film for molding an ultra-thin ceramic green sheet can be produced at low cost.

Surface free energy of the release layer surface of the release layer film of the present invention (gamma] s) is preferably 18 mJ / ^{m 2} or more 35 mJ / ^{m 2} or less. More preferably, 23 mJ / ^{m 2} or more 35 mJ / ^{m 2} or less, further preferably 23 mJ / ^{m 2} or more 30 mJ / ^{m 2} or less. When it is 18 mJ / m ² or more, it is preferable that the ceramic slurry is not easily generated when the ceramic slurry is applied and can be applied uniformly. Further, when it is 35 mJ / m ² or less, there is no possibility that the releasability of the ceramic green sheet is deteriorated, which is preferable. Within the above range, it is possible to provide a release film having excellent releasability without repelling during coating.

The release film of the present invention preferably has a peeling force of 0.5 mN / mm or more and 2.5 mN / mm or less when peeling the ceramic green sheet. More preferably, it is 0.8 mN / mm or more and 2.0 mN / mm or less. When the peeling force is 0.5 mN / mm or more, the peeling force is not too light and there is no possibility that the ceramic green sheet will be lifted during transportation, which is preferable. When the peeling force is 2.5 mN / mm or less, the ceramic green sheet is not likely to be damaged at the time of peeling, which is preferable.

In the release film of the present invention, it is preferable that the amount of the silicone component transferred to the ceramic green sheet after peeling is small. The amount of transfer of the silicone component is determined by applying PVB, which is one of the binder components contained in the ceramic green sheet, onto the release film in a pseudo manner, molding it, and measuring the Si strength of the release layer before and after peeling with fluorescent X-rays. It can be evaluated by measuring. More specifically, when the Si strength of the release layer surface is Si (front) and the Si strength of the release surface of the release film after coating / peeling the PVB sheet is Si (rear), Si (rear). The value of front) -Si (rear) was used as the transfer amount. The transfer amount at this time is preferably 0.10 kcps or less, and more preferably 0.04 kcps or less. When the transfer amount is 0.10 kcps or less, the occurrence of process defects such as stacking misalignment and poor adhesion is suppressed, and there is no risk of deteriorating the reliability of the ceramic capacitor, which is preferable.

The release film of the present invention preferably has a curl of 3 mm or less, more preferably 1 mm or less, after being heated at 80 ° C. for 5 minutes without applying tension. Of course, it is also preferable not to curl at all. It is preferable that the thickness is 3 mm or less because curl is reduced and printing accuracy can be improved when the ceramic green sheet is molded and the electrodes are printed.

In the present invention, the method for forming the release layer is not particularly limited, and a coating liquid in which a releaseable resin is dissolved or dispersed is developed by coating or the like on one surface of a polyester film of a base material, and a solvent or the like is used. Is removed by drying, and then heat-dried and heat-cured. At this time, the drying temperature at the time of solvent drying and thermosetting is preferably 100 ° C. or higher and 180 ° C. or lower, more preferably 100 ° C. or higher and 160 ° C. or lower, and 100 ° C. or higher and 140 ° C. or lower. Is most preferable. The heating time is preferably 30 seconds or less, more preferably 20 seconds or less. When the temperature is 180 ° C. or lower, the flatness of the film is maintained and the risk of causing uneven thickness of the ceramic green sheet is small, which is preferable. When the temperature is 140 ° C. or lower, the film can be processed without impairing the flatness of the film, and the risk of causing uneven thickness of the ceramic green sheet is further reduced, which is particularly preferable. If it is lower than 100 ° C., the curing reaction of melamine does not proceed sufficiently and the elastic modulus of the release layer decreases, which is not preferable.

In the present invention, the surface tension of the coating liquid when the release layer is applied is not particularly limited, but is preferably 30 mN / m or less. By setting the surface tension as described above, the coatability after coating can be improved, and the unevenness of the coating film surface after drying can be reduced.

In the present invention, the coating liquid for applying the release coating layer is not particularly limited, but it is preferable to add a solvent having a boiling point of 90 ° C. or higher. By adding a solvent having a boiling point of 90 ° C. or higher, bumping during drying can be prevented, the coating film can be leveled, and the smoothness of the coating film surface after drying can be improved. The amount to be added is preferably about 10 to 80% by mass with respect to the entire coating liquid.

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

(Ceramic green sheet and ceramic capacitor)
Generally, a monolithic ceramic capacitor has a rectangular parallelepiped ceramic element. Inside the ceramic body, first internal electrodes and second internal electrodes are alternately provided along the thickness direction. The first internal electrode is exposed on the first end face of the ceramic element. 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 on the second end face of the ceramic element. 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 manufacturing a ceramic green sheet of the present invention is used for manufacturing 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 forming a ceramic element is applied and dried. An ultra-thin product having a thickness of 0.2 to 1.0 μm is required for the ceramic green sheet. 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 on which a conductive layer for forming a first internal electrode is printed, and a ceramic green sheet on which a conductive layer for forming a second internal electrode is printed are appropriately laminated and pressed. Thereby, a mother laminated body is obtained. The mother laminate is divided into a plurality of pieces to prepare a raw ceramic element body. A ceramic element is obtained by firing a raw ceramic element. After that, 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 method.

(Surface roughness)
It is a value measured under the following conditions using a non-contact surface shape measurement system (VertScan R550H-M100). For the region surface average roughness (Sa), the average value of 5 measurements was adopted, and for the maximum protrusion height (P), the maximum value of 5 times excluding the maximum value and the minimum value was used after measuring 7 times.
(Measurement condition)
・ Measurement mode: WAVE mode ・ Objective lens: 10x ・ 0.5 × Tube lens ・ Measurement area 936μm × 702μm
(Analysis conditions)
・ Surface correction: 4th correction ・ Interpolation processing: Complete interpolation

(Surface free energy)
Water (droplet volume 1.8 μL) on the release surface of the release film using a contact angle meter (manufactured by Kyowa Interface Science Co., Ltd .: fully automatic contact angle meter DM-701) under the conditions of 25 ° C and 50% RH. , 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 dropping each liquid on the release film was adopted. The contact angle data of water, diiodomethane, and ethylene glycol obtained by the above method were calculated from the "Kitasaki-Hata" theory to obtain the dispersion component γsd, polar component γsp, and hydrogen bond component γsh of the surface free energy of the release film. The sum of each component was defined as the surface free energy γs. This calculation was performed using the calculation software in the contact angle meter software (FAMAS).

(Evaluation of coatability of ceramic rally)
The composition composed of the following materials was stirred and mixed, and dispersed with zirconia beads having a diameter of 0.5 mm for 30 minutes using a bead mill 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 Industry Co., Ltd.) 35.0 parts by mass Polyvinyl butyral (Eslek BM-S manufactured by Sekisui Chemical Co., Ltd.) 3.5 parts by mass DOP (phthalic acid) Dioctyl) 1.8 parts by mass Next, apply an applicator to the release surface of the obtained release film sample so that the dried slurry is 1 μm, dry at 90 ° C for 1 minute, and then apply according to the following criteria. The workability was evaluated. ○: There is no repellent and the entire surface can be coated.
Δ: There is some cissing at the end of the coating, but the coating can be done on almost the entire surface.
×: There are many repellents and the coating has not been completed.

(Pinhole evaluation of ceramic green sheet)
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 coatability of the ceramic slurry. Then, the release film was peeled off from the molded release film with a ceramic green sheet to obtain a ceramic green sheet. In the central region of the obtained ceramic green sheet in the film width direction ^{, light is applied from the opposite surface of the coated surface of the ceramic slurry within a range of 25 cm 2} , and the state of occurrence of pinholes through which light appears is observed, and the following criteria are used. It was judged visually.
○: No pinholes occurred △: Almost no pinholes occurred ×: Many pinholes occurred

(Evaluation of peelability of ceramic green sheet)
The composition composed of the following materials was stirred and mixed, and dispersed with zirconia beads having a diameter of 0.5 mm for 60 minutes using a bead mill 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 Industry Co., Ltd.) 64.8 parts by mass Polyvinyl butyral (Eslek BM-S manufactured by Sekisui Chemical Co., Ltd.) 6.5 parts by mass DOP (phthalic acid) Dioctyl) 3.3 parts by mass Next, apply the dried slurry to a thickness of 0.8 μm on the release surface of the obtained release film sample using an applicator, and dry at 60 ° C for 1 minute to obtain a ceramic green sheet. Was molded on a release film. The obtained release film with a ceramic green sheet is statically removed using an electric eliminator (Keyence, SJ-F020), and then a peeling tester (Kyowa Interface Science, VPA-3) is used to remove the peeling angle of 90 degrees. The peeling was performed at a peeling temperature of 25 ° C. and a peeling speed of 10 m / min. As for the direction of peeling, a double-sided adhesive tape (Nitto Denko Co., Ltd., No. 535A) is attached on the SUS plate attached to the peeling tester, and the ceramic green sheet side is bonded to the double-sided tape on the release film. Was fixed and peeled off by pulling on the release film side. Among the obtained measured values, the average value of the peeling force having a peeling distance of 20 mm to 70 mm was calculated, and the value was used as the peeling force. The measurement was carried out a total of 5 times, and the value of the average value of the peeling force was adopted and evaluated. Judgment was made according to the following criteria from the obtained numerical values of the peeling force.
◯: 0.5 mN / mm or more, 1.0 mN / mm or less Δ: Greater than 1.0 mN / mm, 2.5 mN / mm or less ×: Greater than 2.5 mN / mm

(Evaluation of transfer amount of silicone component in mold release layer)
The composition consisting of the following materials was stirred and mixed to obtain a polyvinyl butyral (PVB) solution.
Toluene 45.0 parts by mass Ethanol 45.0 parts by mass Polyvinyl butyral (ESREC BM-S manufactured by Sekisui Chemical Co., Ltd.) 10.0 parts by mass Next, the release surface of the obtained release film sample is dried using an applicator. The butyral (PVB) sheet was coated to a size of 10 μm, dried at 90 ° C. for 1 minute, and then the release film was peeled off. The Si strength of the release layer of the release film before coating the PVB sheet was measured with a fluorescent X-ray device (ZSX Primus2 manufactured by Rigaku), and the amount of transfer of the silicone component was quantified. The measurement conditions of the fluorescent X-ray apparatus were as follows.
Analysis line: Si-KA, Target: Rh4.0kW
Tube voltage: 50kV, tube current: 60mA
Filter: OUT, Attenuator: 1/1, Slit: S4, Spectral crystal: PET
Detector: PC, PHA condition: 100 (lower limit) -300 (upper limit)
Measurement diameter: 30 mm, atmosphere: vacuum The amount of silicone component transferred is the Si strength of the release surface of the release film before coating the PVB sheet to Si (front), and the release after coating and peeling the PVB sheet. The Si strength of the release surface of the film was defined as Si (rear), and the value obtained by subtracting Si (rear) from Si (front) was defined as the transfer amount of the silicone component. Judgment was made according to the following criteria from the numerical value of the transfer amount of the obtained silicone component.
◯: 0.04 kcps or less Δ: Greater than 0.04 kcps and smaller than 0.10 kcps.
X: 0.10 kcps or more

(Curl evaluation of release film)
The release film sample was cut into a size of 10 cm × 10 cm, and heat-treated at 80 ° C. for 5 minutes in a hot air oven so that tension was not applied to the release film. Then, after taking out from the oven and cooling to room temperature, the mold release film sample was placed on the glass plate so that the mold release surface was facing up, and the heights of the portions floating from the glass plates at the four corners were measured. The average value of the floating amounts of the four corners measured at this time was taken as the curl amount. The curl property was evaluated according to the following criteria.
⊚: The curl is 1 mm or less, and there is almost no curl.
◯: The curl was larger than 1 mm and 3 mm or less, and some curl was observed.
Δ: The curl was larger than 3 mm and 10 mm or less, and curl was observed.
X: The curl was larger than 10 mm.

(Measuring method of weight average degree of polymerization)
Analytical conditions 16 mg of sample was weighed and dissolved in 8 ml of chloroform. Filtration was performed with a 0.2 μm membrane filter, and GPC analysis of the obtained sample solution was performed under the following conditions.

Equipment: TOSOH HLC-8320GPC
Column: K-G + K-802 (exclusion limit molecular weight 5 × 10 ³ ) + K-801 (exclusion limit molecular weight 1.5 × 10 ³ ) (Shodex),
Solvent: 100% chloroform
Flow velocity: 1.0 ml / min
Concentration: 0.2%
Injection volume: 50 μL
Temperature: 40 ℃
Detector: RI
The weight average molecular weight was calculated in terms of polystyrene, and the weight average degree of polymerization was calculated based on the value. For polystyrene, PStQuick C (TOSOH) of the PStQuick series was used. Among the polystyrenes added to PStQuick C (TOSOH), polystyrenes Mw2110000, 427000, and 37900 that greatly exceed the exclusion limit molecular weight of the column are
Removed from calibration curve creation.

(Preparation of polyethylene terephthalate pellets (PET (I)))
As the esterification reaction device, a continuous esterification reaction device consisting of a stirrer, a splitter, a raw material charging port, and a three-stage complete mixing tank having a raw material charging port and a product outlet was used. TPA (terephthalic acid) is 2 tons / hour, EG (ethylene glycol) is 2 mol per 1 mol of TPA, antimony trioxide is an amount of 160 ppm of Sb atom with respect to the PET produced, and these slurrys are esterified. It was continuously supplied to the first esterification reaction can of the chemical reaction apparatus and reacted at normal pressure with an average residence time of 4 hours and 255 ° C. Next, the reaction product in the first esterification reaction can is continuously taken out of the system and supplied to the second esterification reaction can, and distilled off from the first esterification reaction can in the second esterification reaction can. EG is supplied in an amount of 8% by mass with respect to the produced PET, and an EG solution containing magnesium acetate tetrahydrate in an amount of 65 ppm of Mg atoms with respect to the produced PET and 40 ppm of P atoms with respect to the produced PET. An EG solution containing an amount of TMPA (trimethyl phosphate) was added, and the reaction was carried out at normal pressure for an average residence time of 1 hour and 260 ° C. Next, the reaction product of the second esterification reaction can was continuously taken out of the system and supplied to the third esterification reaction can, and 39 MPa (400 kg / cm ² ) was used using a high-pressure disperser (manufactured by Nippon Seiki Co., Ltd.). 0.2 mass% of porous colloidal silica having an average particle size of 0.9 μm and 1 mass% of ammonium salt of polyacrylic acid attached per calcium carbonate after dispersion treatment with an average number of treatments of 5 passes under the pressure of 0.4% by mass of synthetic calcium carbonate having a diameter of 0.6 μm was added as an EG slurry of 10% each, and the reaction was carried out at normal pressure for an average residence time of 0.5 hours and at 260 ° C. The esterification reaction product produced in the third esterification reaction can was continuously supplied to a three-stage continuous polycondensation reaction apparatus to perform polycondensation, and a stainless steel fiber having a 95% cut diameter of 20 μm was sintered. After filtering with a filter, it was subjected to ultracondensation, extruded into water, cooled, and then cut into chips to obtain PET chips with an intrinsic viscosity of 0.60 dl / g (hereinafter abbreviated as PET (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 PET (I) 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)))
The type and content of PET (I) particles were changed to 0.75% by mass of synthetic calcium carbonate having an average particle size of 0.9 μm, to which 1% by mass of ammonium salt of polyacrylic acid was attached per calcium carbonate. PET chips were obtained in the same manner as PET (I) (hereinafter abbreviated as PET (III)). The lubricant content in the PET chip was 0.75% by mass.

(Manufacturing of laminated film X1)
After drying these PET chips, they were melted at 285 ° C, melted at 290 ° C by a separate melt extruder extruder, and a filter obtained by sintering stainless steel fibers having a 95% cut diameter of 15 μm and a filter having a 95% cut diameter. Two-stage filtration of a filter obtained by sintering 15 μm stainless steel particles is performed and merged in the feed block, and PET (I) is surfaced with surface layer B (anti-separable surface side layer) and PET (II) is surfaced. It is laminated so as to be layer A (separation surface side layer), extruded (casting) into a sheet at a speed of 45 m / min, and electrostatically adhered and cooled on a casting drum at 30 ° C. by the electrostatic adhesion method. An unstretched polyethylene terephthalate sheet having an intrinsic viscosity of 0.59 dl / g was obtained. The layer ratio was adjusted so that PET (I) / (II) = 60% by mass / 40% by mass in the discharge amount calculation of each extruder. Next, the unstretched sheet was heated with an infrared heater and then stretched 3.5 times in the vertical direction at a roll temperature of 80 ° C. due to the speed difference between the rolls. Then, it was guided to a tenter and stretched 4.2 times in the lateral direction at 140 ° C. Then, in the heat fixing zone, heat treatment was performed at 210 ° C. Then, a 2.3% relaxation treatment was carried out laterally at 170 ° C. to obtain a biaxially stretched polyethylene terephthalate film X1 having a thickness of 31 μm. The Sa of the surface layer A of the obtained film X1 was 2 nm, and the Sa of the surface layer B was 28 nm.

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

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

(Manufacturing of laminated film X4)
PET (III) is laminated so as to be a surface layer B (release type surface side layer), and PET (II) is laminated to be a surface layer A (release type surface side layer), and the layer ratio is calculated by the discharge amount calculation of each extruder. A biaxially stretched polyethylene terephthalate film X4 having a thickness of 31 μm was obtained in the same manner as the laminated film X1 except that PET (III) / (II) = 80% by mass / 20% by mass. The Sa of the surface layer A of the obtained film X4 was 2 nm, and the Sa of the surface layer B was 30 nm.

(Example 1)
A coating liquid having the following composition is applied onto the surface layer A of the laminated film X1 using reverse gravure so that the release layer thickness after drying is 500 nm, and dried at 120 ° C. for 15 seconds to form an ultrathin layer. A release film for manufacturing a ceramic green sheet was obtained. When a ceramic slurry was applied to the obtained release film and the surface roughness, surface free energy, coatability, peelability, amount of transfer of silicone component, pinholes, and curl were evaluated, good evaluation results were obtained. rice field.
Methyl ethyl ketone 44.50 parts by mass Toluene 44.50 parts by mass Melamine compound 9.50 parts by mass (full ether type methylated melamine, solid content 100%, manufactured by Sanwa Chemical Co., Ltd., trade name MW-30M, weight average degree of polymerization 1 .3)
Release agent 0.50 parts by mass (one-ended carboxyl-modified polydimethylsiloxane, X22-3710, solid content 100%, manufactured by Shin-Etsu Chemical Co., Ltd., alkyl group intervenes between dimethylsiloxane and carboxyl group)
Acid catalyst 1.00 parts by mass (p-toluenesulfonic acid, manufactured by Hitachi Kasei Co., Ltd., trade name: Dryer (registered trademark) 900, solid content: 50%)

(Example 2)
Except for using the coating liquid in which the content of the full ether type methylated melamine in the coating liquid of Example 1 was 9.80 parts by mass and the addition amount of the release agent (X22-3710) was changed to 0.20 parts by mass. Obtained a release film for producing an ultrathin ceramic green sheet in the same manner as in Example 1.

(Example 3)
Except for using the coating liquid in which the content of the full ether type methylated melamine in the coating liquid of Example 1 was 9.00 parts by mass and the addition amount of the release agent (X22-3710) was changed to 1.00 parts by mass. Obtained a release film for producing an ultrathin ceramic green sheet in the same manner as in Example 1.

(Example 4)
Except for using the coating liquid in which the content of the full ether type methylated melamine in the coating liquid of Example 1 was 8.00 parts by mass and the addition amount of the release agent (X22-3710) was changed to 2.00 parts by mass. Obtained a release film for producing an ultrathin ceramic green sheet in the same manner as in Example 1.
(Examples 5 to 8)
A mold release film for manufacturing an ultrathin ceramic green sheet was obtained in the same manner as in Example 1 except that the film thickness of the release layer was changed to the film thickness shown in Table 1.

(Example 9)
A release film for producing an ultrathin ceramic green sheet was obtained in the same manner as in Example 1 except that the base film of Example 1 was changed to a laminated film X2 having a film thickness of 25 μm.

(Example 10)
A release film for producing an ultra-thin ceramic green sheet was obtained in the same manner as in Example 1 except that the laminated film of Example 1 was changed to the laminated film X3.

(Example 11)
A release film for manufacturing an ultrathin ceramic green sheet was obtained in the same manner as in Example 1 except that the laminated film of Example 1 was changed to the laminated film X4.

(Example 12)
Except for the use of the coating liquid in which the content of the acid catalyst (dryer (registered trademark) 900) of the coating liquid of Example 1 was 0.20 parts by mass (the ratio to the melamine-based compound was 1% by weight). A release film for producing an ultrathin ceramic green sheet was obtained in the same manner as in Example 1.

(Example 13)
Except for using a coating liquid in which the content of the acid catalyst (dryer (registered trademark) 900) of the coating liquid 1 of Example 1 was 1.80 parts by mass (the ratio to the melamine-based compound was 9% by weight). Obtained a release film for producing an ultrathin ceramic green sheet in the same manner as in Example 1.

(Example 14)
A release film for producing an ultrathin ceramic sheet was obtained in the same manner as in Example 1 except that the coating liquid was changed to the following composition. US-350 is an acrylic resin in which a silicone side chain is introduced into an acrylic main chain having a carboxyl group.
Methyl ethyl ketone 43.91 parts by mass Toluene 43.91 parts by mass Melamine compound 9.50 parts by mass (full ether type methylated melamine, solid content 100%, manufactured by Sanwa Chemical Co., Ltd., trade name MW-30M, weight average degree of polymerization 1 .3)
Release agent 1.68 parts by mass (carboxyl group-containing silicone copolymer acrylic resin, US-350, solid content 30%, manufactured by Toagosei Co., Ltd.)
Acid catalyst 1.00 parts by mass (p-toluenesulfonic acid, manufactured by Hitachi Kasei Co., Ltd., trade name: Dryer (registered trademark) 900, solid content: 50%)

(Example 15)
A release film for producing an ultrathin ceramic sheet was obtained in the same manner as in Example 1 except that the coating liquid was changed to the following composition. US-450 is an acrylic resin in which a silicone side chain is introduced into an acrylic main chain having two types of functional groups (carboxyl group and hydroxyl group) in one molecule.
Methyl ethyl ketone 43.91 parts by mass Toluene 43.91 parts by mass Melamine compound 9.50 parts by mass (full ether type methylated melamine, solid content 100%, manufactured by Sanwa Chemical Co., Ltd., trade name MW-30M, weight average degree of polymerization 1 .3)
Release agent 1.68 parts by mass (carboxyl group / OH group-containing silicone copolymer acrylic resin, US-450, solid content 30%, manufactured by Toagosei Corporation)
Acid catalyst 1.00 parts by mass (p-toluenesulfonic acid, manufactured by Hitachi Kasei Co., Ltd., trade name: Dryer (registered trademark) 900, solid content: 50%)

(Example 16)
The same as in Example 1 except that the full ether type methylated melamine of Example 1 was changed to MW-30 (weight average degree of polymerization 1.5) manufactured by Sanwa Chemical Co., Ltd. A release film for manufacturing a thin ceramic green sheet was obtained.

(Example 17)
A release film for producing an ultrathin ceramic sheet was obtained in the same manner as in Example 1 except that the coating liquid was changed to the following composition.
Methyl ethyl ketone 42.46 parts by mass Toluene 42.47 parts by mass Melamine compound 13.57 parts by mass (full ether type methylated melamine, solid content 70%, manufactured by Sanwa Chemical Co., Ltd., trade name MS-21, weight average degree of polymerization 1 .8)
Release agent 0.50 parts by mass (both-terminal carboxyl-modified polydimethylsiloxane, X22-162C, solid content 100%, manufactured by Shin-Etsu Chemical Co., Ltd.)
Acid catalyst 1.00 parts by mass (p-toluenesulfonic acid, manufactured by Hitachi Kasei Co., Ltd., trade name: Dryer (registered trademark) 900, solid content: 50%)

(Example 18)
A release film for producing an ultrathin ceramic sheet was obtained in the same manner as in Example 1 except that the coating liquid was changed to the following composition.
Methyl ethyl ketone 41.34 parts by mass Toluene 41.33 parts by mass Melamine compound 15.83 parts by mass (methylol-type methylated melamine, solid content 60%, Sanwa Chemical Co., Ltd., trade name MS-11, weight average degree of polymerization 1.8 )
Release agent 0.50 parts by mass (both-terminal carboxyl-modified polydimethylsiloxane, X22-162C, solid content 100%, manufactured by Shin-Etsu Chemical Co., Ltd.)
Acid catalyst 1.00 parts by mass (p-toluenesulfonic acid, manufactured by Hitachi Kasei Co., Ltd., trade name: Dryer (registered trademark) 900, solid content: 50%)

(Example 19)
A release film for producing an ultrathin ceramic sheet was obtained in the same manner as in Example 1 except that the coating liquid was changed to the following composition.
Methyl ethyl ketone 44.50 parts by mass Toluene 44.50 parts by mass Melamine compound 9.50 parts by mass (full ether type methylated melamine, solid content 100%, manufactured by Sanwa Chemical Co., Ltd., trade name MW-30M, weight average degree of polymerization 1 .3)
Release agent 0.50 parts by mass (side chain type carboxyl-modified polydimethylsiloxane, X22-3701E, solid content 100%, manufactured by Shin-Etsu Chemical Co., Ltd.)
Acid catalyst 1.00 parts by mass (p-toluenesulfonic acid, manufactured by Hitachi Kasei Co., Ltd., trade name: Dryer (registered trademark) 900, solid content: 50%)

(Example 20)
A release film for producing an ultrathin ceramic sheet was obtained in the same manner as in Example 1 except that the coating liquid was changed to the following composition.
Methyl ethyl ketone 44.50 parts by mass Toluene 44.50 parts by mass Melamine compound 9.50 parts by mass (full ether type methylated melamine, solid content 100%, manufactured by Sanwa Chemical Co., Ltd., trade name MW-30M, weight average degree of polymerization 1 .3)
Release agent 0.50 parts by mass (both-terminal carboxyl-modified polydimethylsiloxane, X22-162C, solid content 100%, manufactured by Shin-Etsu Chemical Co., Ltd.)
Acid catalyst 1.00 parts by mass (p-toluenesulfonic acid, manufactured by Hitachi Kasei Co., Ltd., trade name: Dryer (registered trademark) 900, solid content: 50%)

(Example 21)
Same as Example 1 except that the acid catalyst of the coating liquid of Example 1 was changed to dinonylnaphthalenedisulfonic acid (manufactured by Kusunoki Kasei Co., Ltd., trade name NACURE (registered trademark) 155, active ingredient 55%). Then, a release film for manufacturing an ultra-thin ceramic green sheet was obtained.

(Example 22)
Examples except that the acid catalyst of the coating liquid of Example 1 was changed to dinonylnaphthalene (mono) sulfonic acid (manufactured by Kusunoki Kasei Co., Ltd., trade name NACURE (registered trademark) 1051, active ingredient 50%). In the same manner as in No. 1, a release film for producing an ultrathin ceramic green sheet was obtained.

(Comparative Example 1)
A mold release film for producing an ultra-thin ceramic sheet was obtained by the same method as in Example 1 except that a coating liquid containing no mold release agent was used for the coating liquid of Example 1. Since the release agent was not contained, the peeling force was heavy and many pinholes were generated.

(Comparative Example 2)
A release film for producing an ultrathin ceramic sheet was obtained in the same manner as in Example 1 except that the coating liquid was changed to the following composition. In Comparative Example 2 in which a large amount of mold release agent was added and the melamine compound was only 70% by mass of the mold release layer, the amount of silicone transferred to the ceramic green sheet was large.
Methyl ethyl ketone 44.50 parts by mass Toluene 44.50 parts by mass Melamine compound 7.00 parts by mass (full ether type methylated melamine, solid content 100%, manufactured by Sanwa Chemical Co., Ltd., trade name MW-30M, weight average degree of polymerization 1 .3)
Release agent 3.00 parts by mass (one-ended carboxyl-modified polydimethylsiloxane, X22-3710, solid content 100%, manufactured by Shin-Etsu Chemical Co., Ltd.)
Acid catalyst 1.00 parts by mass (p-toluenesulfonic acid, manufactured by Hitachi Kasei Co., Ltd., trade name: Dryer (registered trademark) 900, solid content: 50%)

(Comparative Example 3)
A release film for producing an ultrathin ceramic sheet was obtained in the same manner as in Example 1 except that the coating liquid was changed to the following composition. The amount of silicone transfer is low and good, but the interaction between the hydroxyl group and the melamine compound is strong, and the crosslink density is low probably because the silicone is not exposed on the surface and the weight average molecular weight of the melamine compound is high. The peeling force became heavy.
Methyl ethyl ketone 43.33 parts by mass Toluene 43.33 parts by mass Melamine compound 12.49 parts by mass (imino-type methylated melamine, solid content 80%, manufactured by Sanwa Chemical Co., Ltd., trade name MX-730, weight average degree of polymerization 2. 4)
Release agent 0.05 parts by mass (polyether-modified OH group-containing polydimethylsiloxane, BYK-377, solid content 100%, manufactured by Big Chemie Japan)
Acid catalyst 0.80 parts by mass (p-toluenesulfonic acid, manufactured by Hitachi Kasei Co., Ltd., trade name dryer (registered trademark) 900, solid content 50%)

(Comparative Example 4)
A release film for producing an ultrathin ceramic sheet was obtained in the same manner as in Example 1 except that the coating liquid was changed to a coating liquid having the following composition. The peeling force became heavier probably because the crosslink density was low due to the high weight average molecular weight of the melamine compound.
Methyl ethyl ketone 43.32 parts by mass Toluene 43.32 parts by mass Melamine 11.86 parts by mass (imino-type methylated melamine, solid content 80%, manufactured by Sanwa Chemical Co., Ltd., trade name MX-730, weight average degree of polymerization 2.4)
Release agent 0.50 parts by mass (one-ended carboxyl-modified polydimethylsiloxane, X22-3710, solid content 100%, manufactured by Shin-Etsu Chemical Co., Ltd., alkyl group intervenes between dimethylsiloxane and carboxyl group)
Acid catalyst 1.00 parts by mass (p-toluenesulfonic acid, manufactured by Hitachi Kasei Co., Ltd., trade name: Dryer (registered trademark) 900, solid content: 50%)

(Comparative Example 5)
A release film for producing an ultrathin ceramic sheet was obtained in the same manner as in Example 1 except that the coating liquid was changed to a coating liquid having the following composition. The peeling force became heavier probably because the crosslink density was low due to the high weight average molecular weight of the melamine compound.
Methyl ethyl ketone 41.34 parts by mass Toluene 41.34 parts by mass Melamine 15.82 parts by mass (imino-methylol type methylated melamine, solid content 60%, manufactured by Sanwa Chemical Co., Ltd., trade name MS-001, weight average degree of polymerization 5. 7)
Release agent 0.50 parts by mass (one-ended carboxyl-modified polydimethylsiloxane, X22-3710, solid content 100%, manufactured by Shin-Etsu Chemical Co., Ltd., alkyl group intervenes between dimethylsiloxane and carboxyl group)
Acid catalyst 1.00 parts by mass (p-toluenesulfonic acid, manufactured by Hitachi Kasei Co., Ltd., trade name: Dryer (registered trademark) 900, solid content: 50%)

According to the present invention, the surface of the release layer is smooth, and the ceramic green sheet can be peeled off with a low and uniform force as compared with the conventional release film for manufacturing a ceramic green sheet, so that the thickness is 1 μm or less. Even the ultra-thin layer ceramic green sheet can be manufactured without causing defects such as pinholes.

Claims (6)

The biaxially oriented polyester film as a base material, has a surface layer A, wherein the base material is not substantially free of inorganic particles on at least one surface, directly on the surface of at least one surface of the surface layer A, the release layer Are laminated,
The surface layer A contains a polyethylene terephthalate resin and contains.
The surface layer A has a surface average roughness (Sa) of 1 to 7 nm.
The release layer is formed by curing a composition containing at least a release agent and a melamine-based compound, and the release agent is a polyorganosiloxane containing a carboxyl group.
The weight average degree of polymerization of the melamine compound is 2.0 or less, and the content of the melamine compound is 80% by mass or more with respect to the solid content of the release layer forming composition.
Release film for manufacturing ceramic green sheets. One side of the substrate has a surface layer A that does not substantially contain inorganic particles, the surface layer B has a surface layer B on the opposite side of the substrate from the surface layer A, and the surface layer B contains particles. The release film for producing a ceramic green sheet according to claim 1, wherein at least a part of the particles is silica particles and / or calcium carbonate particles, and the total content of the particles with respect to the mass of the surface layer B is 5000 to 15000 ppm. The release film for producing a ceramic green sheet according to claim 1 or 2, wherein the region surface average roughness (Sa) of the release layer is 7 nm or less, and the maximum protrusion height (P) is 100 nm or less. The release film for producing a ceramic green sheet according to any one of claims 1 to 3, wherein the surface layer A contains a polyethylene terephthalate resin as a main component. A method for manufacturing a ceramic green sheet using the release film for manufacturing a ceramic green sheet according to any one of claims 1 to 4, wherein the molded ceramic green sheet is 0.2 μm to 1 .. A method for manufacturing a ceramic green sheet having a thickness of 0 μm. A method for manufacturing a ceramic capacitor, which employs the method for manufacturing a ceramic green sheet according to claim 5.