JP2019116086A - Release film for manufacturing ceramic green sheet - Google Patents

Abstract

To provide a release film for manufacturing a ceramic green sheet having no aggravation of detachability even when thickness of the release film is made thin, having no aggravation of runnability generated by curl, and hardly generating pin hole defect or the like on a molded ultrathin ceramic green sheet.SOLUTION: There is provided a release sheet for manufacturing a ceramic green sheet, in which a release sheet with 0.2 to 2.0 μm on at least a single surface of a polyester film directly or via other layers, area surface roughness (Sa) of a release layer surface is 7 nm or less, and the release layer is manufactured by curing a coated film containing at least an energy ray curing type copolymer acrylic resin having a (meth)acryloyl group and a polyorganosiloxane group in a molecule and weight average molecular weight of 2,000 to 100,000.SELECTED DRAWING: None

Description

  The present invention relates to a release film for producing an ultrathin layer ceramic green sheet, and in particular, it is possible to produce a film in which the occurrence of process defects due to pinholes and thickness unevenness is suppressed at the time of producing an ultrathin layer ceramic green sheet. The present invention relates to a release film for producing an ultra-thin layer ceramic green sheet.

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

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

  Further, in recent years, it is required to reduce the thickness of the release film from the viewpoint of environmental load and cost reduction. However, if the thickness of the release film is reduced, the smoothness of the surface of the release film may be reduced, or the stiffness of the release film may be reduced to cause curling, etc. There is a problem that the traveling property of the mold film is deteriorated. More specifically, when the traveling property of the release film is deteriorated, the uniformity at the time of coating and forming of the ceramic green sheet is deteriorated, the film thickness of the ceramic green sheet becomes uneven, and the printing accuracy in the electrode printing process There is a problem that the defect rate of the molded MLCC is deteriorated.

  As a method of suppressing the load on the ceramic green sheet at the time of peeling, the crosslinking density of the releasing layer is increased by using an active energy ray curing component in the releasing layer of the releasing film, and the elastic modulus is improved. A measure to reduce the peeling force by suppressing the deformation of the release layer at the time of peeling the ceramic green sheet has been studied (for example, Patent Documents 2 and 3).

  However, just increasing the crosslinking density of the release layer as in Patent Documents 2 and 3 may result in an increase in curing shrinkage of the release layer, causing curling in the release film after release layer processing, and running property There was a concern that would worsen. In addition, if the curing is insufficient, the solvent resistance of the release layer is deteriorated, so that the release layer is corroded by the organic solvent used at the time of ceramic green sheet processing or electrode printing, for example, toluene, etc. And could cause damage to the ceramic green sheet at the time of peeling. Furthermore, when curing was insufficient, there was a concern that a large amount of the silicone component was transferred to the green sheet, and the adhesion between the green sheets was reduced. In particular, when the thickness of the release film becomes thin, curling becomes more remarkable, and while the problem occurs when molding the ceramic green sheet, when the release layer is made thinner, curing inhibition occurs and generation of peeling defects and silicone transfer amount increase. There was a concern.

JP 2000-117899 A International Publication No. 2013/145864 International Publication No. 2013/145865

  As a result of intensive investigations in view of the above situation, the inventors of the present invention, by using a specific material for the release layer of the release film, makes compatible high crosslink density of the release layer, low cure shrinkage, and low silicone migration. I found out. And, the subject of the present invention is that even if the thickness of the release film is made thin, there is no deterioration in releasability and no deterioration in running property caused by curling, and pinhole defects etc. occur in the molded ultrathin ceramic green sheet. It is an object of the present invention to provide a difficult release film for producing a ceramic green sheet.

That is, the present invention has the following constitution.
1. A release film in which a release layer of 0.2 to 2.0 μm is laminated on at least one surface of a polyester film directly or through another layer, and the area surface roughness (Sa) of the release layer surface is 7 nm The coating film containing at least an energy ray-curable copolymerized acrylic resin having a weight average molecular weight of 2000 to 100,000 having a (meth) acryloyl group and a polyorganosiloxane group in one molecule is cured. Release film for producing ceramic green sheets.
2. The release layer contains an energy ray-curable resin component and a polyorganosiloxane component other than an energy ray-curable copolymerized acrylic resin having a molecular weight of 2,000 to 100,000 having a (meth) acryloyl group and a polyorganosiloxane group in one molecule. The release film for producing a ceramic green sheet according to the above first aspect.
3. An energy ray-curable copolymerized acrylic resin having a weight average molecular weight of 2,000 to 100,000 having a (meth) acryloyl group and a polyorganosiloxane group in one molecule, a monomer having a (meth) acryloyl group precursor and a polyorganosiloxane A compound having a (meth) acryloyl group is grafted to an acrylic copolymer (I) in which a plurality of types of monomers including at least a monomer having a group are copolymerized, and the acrylic copolymer (I) The release according to the first or the second according to the first or the second, wherein the amount of polyorganosiloxane group introduced is 0.01 to 10 mol%, and the amount of introduction of (meth) acryloyl group by grafting is 70 to 99.95 mol%. Mold film.
4. A laminated polyester film comprising at least two layers of polyester films, wherein the surface layer A on the side on which the release layer of the laminated polyester film is laminated is substantially free of inorganic particles. The release film for ceramic green sheet manufacture in any one of 3.
5. The surface layer B on the opposite side to the surface layer A of the laminated polyester film contains particles, the particles are silica particles and / or calcium carbonate particles, and the total content of particles relative to the total mass of the surface layer B The mold release film for producing a ceramic green sheet according to the above fourth, which has a weight of 5000 to 15000 ppm.
6. 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 the said 1st-5th, Comprising: 0.2 micrometers-of the ceramic green sheet shape | molded A method of producing a ceramic green sheet having a thickness of 1.0 μm.

  The release film for producing a ceramic green sheet according to the present invention has a smaller amount of curling and transfer to silicone and is excellent in releasability as compared with a conventional release film for producing a ceramic green sheet, so the thickness of the release film is reduced. However, it has become possible to provide a release film for producing a ceramic green sheet which can reduce defects such as pinholes in an ultrathin ceramic green sheet having a thickness of 1 μm or less to be molded.

  Hereinafter, the present invention will be described in detail.

  The release film for producing an ultrathin ceramic green sheet according to the present invention has a release layer on at least one side of a polyester film, and the release layer contains a (meth) acryloyl group and a polyorganosiloxane in one molecule. A release film for producing a ceramic green sheet, which is obtained by curing a coating film containing at least an energy ray-curable copolymerized acrylic resin having a weight average molecular weight of 2,000 to 100,000 having a group is a preferable embodiment. .

(Polyester film)
The polyester constituting the polyester film to be used as a substrate in the present invention is not particularly limited, and a polyester film generally used as a substrate for a release film may be used, but preferably It may be a crystalline linear saturated polyester comprising an aromatic dibasic acid component and a diol component, for example, polyethylene terephthalate, polyethylene 2,6 naphthalate, polybutylene terephthalate, polytrimethylene terephthalate or resins thereof. Copolymers having a component as a main component are more preferred, and polyester films formed from polyethylene terephthalate are particularly preferred. In polyethylene terephthalate, the repeating unit of ethylene terephthalate is preferably 90 mol% or more, more preferably 95 mol% or more, and small amounts of other dicarboxylic acid components and diol components may be copolymerized, but from the viewpoint of cost And those produced solely from terephthalic acid and ethylene glycol. In addition, known additives, for example, an antioxidant, a light stabilizer, an ultraviolet light absorber, a crystallization agent, and the like may be added within a range not to inhibit the effect of the release film of the present invention. The polyester film is preferably a biaxially oriented polyester film for reasons such as the height of the elastic modulus in both directions.

  The intrinsic viscosity of the polyethylene terephthalate film is preferably 0.50 to 0.70 dl / g, more preferably 0.52 to 0.62 dl / g. When the intrinsic viscosity is 0.50 dl / g or more, a large number of fractures do not occur in the stretching step, which is preferable. On the contrary, when it is 0.70 dl / g or less, it is preferable because the cutting property when cutting into a predetermined product width is good and dimensional defects do not occur. In addition, it is preferable that the raw material be sufficiently vacuum dried.

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

  In the present invention, the stretching temperature at the time of stretching the polyester film is preferably at least the secondary transition point (Tg) of the polyester. It is preferable to stretch 1 to 8 times, particularly 2 to 6 times in the longitudinal and transverse directions.

  The polyester film preferably has a thickness of 12 to 50 μm, more preferably 15 to 38 μm, and still more preferably 19 to 33 μm. If the thickness of the film is 12 μm or more, there is no risk of deformation due to heat at the time of film production, processing steps, and molding, which is preferable. 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 large, which is preferable in reducing the environmental load.

  The polyester film substrate may be a single layer or a multilayer of two or more layers, but it is preferable to have a surface layer A substantially free of inorganic 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 capable of containing inorganic particles and the like on the opposite surface of the surface layer A substantially not containing inorganic particles. Assuming that the layer to which the release layer is applied is layer A, the layer on the opposite side is layer B, and the core layer other than these layers is layer C, the layer configuration in the thickness direction is release layer / A /. B, or a laminated structure of release layer / A / C / B or the like. Naturally, the C layer may have a plurality of layer configurations. The surface layer B can also contain no inorganic particles. In that case, it is preferable to provide a coat layer containing at least inorganic particles and a binder on the surface layer B in order to impart slipperiness for winding the film into a roll.

  In the polyester film substrate in the present invention, it is preferable that the surface layer A forming the surface to which the release layer is applied does not substantially contain inorganic particles. At this time, the area average surface roughness (Sa) of the surface layer A is preferably 7 nm or less. It is preferable that occurrence of pinholes and the like does not easily occur at the time of molding of the laminated ultrathin ceramic green sheet that Sa is 7 nm or less. The area average surface roughness (Sa) of the surface layer A is preferably as small as possible, but may be 0.1 nm or more. Here, when providing the below-mentioned anchor coat layer etc. on surface layer A, it is preferable that an inorganic particle is not included in a coat layer substantially, and the field surface average roughness (Sa) after coat layer lamination is the above-mentioned range Is preferred. In the present invention, the phrase "containing substantially no inorganic particles" means that the inorganic particles are 50 ppm or less, preferably 10 ppm or less, most preferably the detection limit or less when the inorganic element is quantified by fluorescent X-ray analysis. Means quantity. This is because, even if the inorganic particles are not positively added to the film, contamination components derived from extraneous foreign matter, stains attached to the lines and devices in the manufacturing process of the raw material resin or the film are peeled off and mixed in the film. It is because there is a case.

  In the polyester film substrate according to the present invention, the surface layer B forming the opposite surface of the surface to which the release layer is applied preferably contains inorganic particles from the viewpoint of film slipperiness and ease of removal of air, In particular, silica particles and / or calcium carbonate particles are preferably used. It is preferable that the inorganic particle content to be contained is 5000 to 15000 ppm in total of the inorganic particles in the surface layer B. At this time, it is preferable that the area | region surface average roughness (Sa) of the film of surface layer B is the range of 1-40 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 up, and the winding appearance is good and flatness is good. And ultra-thin ceramic green sheets. 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, aggregation of the lubricant is difficult to occur and coarse projections can not be made, so the quality is stable at the time of manufacturing ceramic green sheet of ultrathin layer. Preferred.

  In addition to silica and / or calcium carbonate, inactive inorganic particles and / or heat-resistant organic particles can be used as the particles contained in the above-mentioned B layer, but from the viewpoint of transparency and cost, silica particles and / or It is more preferable to use calcium carbonate particles, but examples of inorganic particles that can be used include alumina-silica composite oxide particles and hydroxyapatite particles. Further, as the heat resistant organic particles, crosslinked polyacrylic particles, crosslinked polystyrene particles, benzoguanamine particles and the like can be mentioned. When silica particles are used, porous colloidal silica is preferable, and when calcium carbonate particles are used, light calcium carbonate which has been surface-treated with a polyacrylic acid-based polymer compound is preferable from the viewpoint of preventing the slippage of the lubricant. .

  The average particle diameter of the inorganic particles added to the surface layer B is preferably 0.1 μm to 2.0 μm and particularly preferably 0.5 μm to 1.0 μm. If the average particle diameter of the inorganic particles is 0.1 μm or more, the slipperiness of the release film is good, which is preferable. In addition, if the average particle diameter is 2.0 μm or less, there is no possibility that pinholes 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 kinds of particles different in material. Further, particles of the same type but different in average particle diameter may be contained.

  In the case where the surface layer B does not contain particles, it is preferable that the coat layer containing the particles on the surface layer B have lubricity. The present coating layer is not particularly limited, but is preferably provided by in-line coating which is applied during film formation of a polyester film. When the surface layer B does not contain particles but has a coat layer containing particles on the surface layer B, the surface of the coat layer is an area for the same reason as the area average roughness (Sa) of the above-mentioned 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.

  In order to prevent the mixing of inorganic particles such as a lubricant, it is preferable not to use a regeneration raw material or the like from the viewpoint of reducing pinholes in the surface layer A which is the layer on the side where the release layer is provided.

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

  Further, from the viewpoint of economy, 50 to 90% by mass of film scraps and recycled materials for plastic 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 layer B, the particle size, and the area surface average roughness (Sa) satisfy the above range.

  In addition, a film after stretching or uniaxial stretching in the film forming process on the surface of the surface layer A and / or the surface layer B in order to improve adhesion of a release layer applied later or to prevent charging etc. May be provided with a coating layer, or may be subjected to corona treatment or the like.

(Release layer)
The release layer of the present invention is preferably formed by curing a coating film containing at least an energy ray-curable copolymerized acrylic resin having a (meth) acryloyl group and a polyorganosiloxane group in one molecule. By using an energy ray-curable copolymerized acrylic resin having a (meth) acryloyl group and a polyorganosiloxane group in one molecule, it is possible to improve the crosslinking density while suppressing the cure shrinkage of the release layer, The solvent resistance of the mold layer is improved, and the erosion of the release layer by the organic solvent at the time of ceramic sheet processing and electrode printing can be suppressed. Moreover, since the polyorganosiloxane group is introduce | transduced in the molecule | numerator, since it can suppress transferring to a ceramic green sheet, it is preferable.

  The release layer of the present invention preferably contains no polyorganosiloxane component other than the energy ray-curable copolymerized acrylic resin having a (meth) acryloyl group and a polyorganosiloxane group in one molecule. By using a release layer having such a configuration, it is preferable to prevent segregation of the silicone component not incorporated in the crosslinked structure on the surface of the release layer and to suppress migration of silicone. Moreover, since a crosslinking reaction can advance only by setting it as the mold release layer of such a structure, and a curing | hardening shrinkage | contraction can be suppressed only between energy beam-curable copolymerized acrylic resins, it is preferable. Here, "does not contain a polyorganosiloxane component" means that, in order to impart a specific function, for example, a function such as releasability to the coating film forming the release layer, intentionally within one molecule. It indicates that polyorganosiloxane components other than the energy ray-curable copolymerized acrylic resin having a (meth) acryloyl group and a polyorganosiloxane group are not added. Then, when there is mixing of a very small amount of by-products and impurities derived from the raw material when synthesizing the energy ray-curable copolymerized acrylic resin, and mixing of the silicone component remaining in the step of forming the releasing layer. Also, it is a minor amount, not a polyorganosiloxane component.

  The weight average molecular weight of the energy ray-curable copolymerized acrylic resin having a (meth) acryloyl group and a polyorganosiloxane group in one molecule, which is used in the release layer of the present invention, is preferably 2000 to 100,000, 2000 It is more preferable that it is 50,000, and it is further more preferable that it is 2000-30,000. When the weight average molecular weight is 2000 or more, the amount of the introduced polyorganosiloxane group is not extremely reduced, and it is preferable because the peelability is excellent. When the weight average molecular weight is 100,000 or less, the reaction between (meth) acryloyl groups in the molecule is suppressed, and the (meth) acryloyl group crosslinks between molecules, which is preferable because the effect of increasing the crosslink density is obtained .

(Energy ray-curable copolymerized acrylic resin)
The energy ray-curable copolymerized acrylic resin used in the present invention refers to one having a (meth) acryloyl group and a polyorganosiloxane group in one molecule. More specifically, it refers to an acrylic resin having a siloxane group and a (meth) acryloyl group in the molecule, and includes a polydimethylsiloxane (sometimes called an acrylic modified silicone) containing a (meth) acryloyl group. Absent.

  The energy ray-curable copolymerized acrylic resin used in the present invention is an acrylic copolymer of a precursor synthesized by copolymerizing a monomer having a (meth) acryloyl group precursor and a monomer having a polyorganosiloxane group (I ) Can be obtained by grafting a (meth) acryloyl group.

  Monomers having a precursor of (meth) acryloyl group include hydroxylalkyl groups such as 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, etc. ) Acrylic esters, (meth) acrylic esters having a carboxyl group such as (meth) acrylic acid, 3-buten-1-ol, 4-penten-2-ol, 1-penten-3-ol, 4- Alkenyl compounds having a hydroxyl group such as pentene-1-ol, crotonic acid, myristhic acid, palmitoleic acid, Sapienic acid, oleic acid, oleic acid, bacillic acid, gadeuric acid, eicosenic acid, erucic acid, nelvic acid, etc. An alkenyl compound having Jill (meth) acrylate, epoxy-modified acrylate compounds, such as 4-hydroxybutyl acrylate glycidyl ether.

  As a monomer having a polyorganosiloxane group, for example, (meth) acryloyl-modified polyorganosiloxane or the like corresponds, and as a product name, X-22-174 ASX manufactured by Shin-Etsu Chemical Co., Ltd., X-22-174 BX, KF -2012, X-22-2426, X-22-2404 etc. is mentioned.

  There is no particular limitation on the method of grafting the (meth) acryloyl group to the acrylic copolymer (I) of the precursor, for example, a hydroxyl group or a carboxyl group, an isocyanate group and an acryloyl group in the molecule such as isocyanuricethyl (meth) acrylate. Examples thereof include a method of reacting with a compound having a group, and a method of reacting an epoxy group and (meth) acrylic acid to obtain a (meth) acrylic ester.

  In the energy ray-curable copolymerized acrylic resin used in the present invention, it is preferable to introduce 0.01 to 10 mol% of a polyorganosiloxane group into one molecule of the acrylic copolymer as a precursor, and introduce 0.03 to 5 mol%. It is more preferable to introduce 0.05 to 5 mol%. By introducing a polyorganosiloxane group in an amount of 0.01 mol% or more, sufficient releasability of the release layer is developed, and when the ceramic green sheet is peeled off, the ceramic layer can be peeled off without damaging the ceramic layer. The introduction of 10 mol% or less is preferable because repelling is less likely to occur when the ceramic slurry is applied, and a uniform ceramic green sheet can be formed. In addition, since it is difficult to directly evaluate the introduction amount of the polyorganosiloxane group, in the present specification, when synthesizing the acrylic copolymer (I) which is a precursor of the energy ray-curable copolymerized acrylic resin It is shown by the value calculated from the input amount of monomers having a polyorganosiloxane group. Specifically, the value which represented the mole number of the polyorganosiloxane group contained in the monomer which has a polyorganosiloxane group with respect to the mole number of all the component monomers thrown in at the time of synthesize | combining acrylic copolymer (I) in mol% Is the introduction amount of polyorganosiloxane group.

  In the energy ray-curable copolymerized acrylic resin used in the present invention, it is preferable that 70 to 99.95 mol% of (meth) acryloyl group be introduced into one molecule of the acrylic copolymer as a precursor, and 80 to 99.95 mol It is more preferable that% is introduced. By introducing 70 mol% or more of (meth) acryloyl group, the crosslink density of the release layer is improved, and the solvent resistance is improved. Therefore, the release layer is corroded by an organic solvent at the time of ceramic sheet processing or electrode printing. It is preferable because there is no The introduction amount of 99.95 mol% or less is preferable because the introduction amount of the polyorganosiloxane group does not extremely decrease and the peelability is excellent. In addition, since it is difficult to directly evaluate the introduction amount of (meth) acryloyl group, in the present specification, it is assumed that the grafting reaction has completely proceeded, and the precursor of the energy ray-curable copolymerized acrylic resin is assumed. This is shown by a value calculated from the amount of the monomer having a precursor of (meth) acryloyl group at the time of synthesizing the acrylic copolymer (I) which is a body. Specifically, the number of moles of (meth) acryloyl group produced by the grafting of the compound having a (meth) acryloyl group to the number of moles of all the monomers introduced when synthesizing the acrylic copolymer (I) The value which represented by mol% is made into the introduction | transduction amount of (meth) acryloyl group.

  It is not necessary to graft the (meth) acryloyl group to all of the functional groups of the precursor acrylic copolymer (I). When a hydroxyl group, a carboxyl group, an epoxy group, etc. remain in the energy ray-curable copolymerized acrylic resin, it is possible to control the crosslinking density by using a heat-crosslinking-type curing agent in combination. Moreover, when a hydroxyl group arises when grafting with acrylic copolymer (I), the hydroxyl group can also be made to react with a heat-crosslinking-type curing agent to control the crosslink density. For example, in the grafting reaction of acrylic copolymer (I) containing an epoxy group and (meth) acrylic acid, and the grafting reaction of acrylic copolymer (I) containing a carboxyl group with glycidyl (meth) acrylate, hydroxyl groups are generated. It can be used in combination with a heat crosslinkable curing agent.

  As a heat crosslinking type curing agent, an isocyanate type curing agent, a metal chelate type curing agent, an epoxy curing agent, an aziridine type curing agent, a melamine type curing agent, an oxazoline type curing agent, etc. can be used without particular limitation.

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

  The addition amount of the photopolymerization initiator is not particularly limited. For example, it is preferable to use about 0.1 to 20% by mass with respect to the resin to be used.

(Sensitizer)
In the case of UV curing, sensitizers can be used. As a sensitizer, an amine type, a thiol type, etc. can be used without particular limitation.

(Other ingredients)
The release layer of the present invention can contain particles having a particle diameter of 1 μm or less, but it is preferable not to contain particles that form projections such as particles 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 of the present invention as long as the effects of the present invention are not impaired. Further, in order to improve the adhesion to the substrate, it is also preferable to subject the polyester film surface to pretreatment such as anchor coating, corona treatment, plasma treatment, atmospheric pressure plasma treatment or the like before the release coating layer is provided.

  In the present invention, the thickness of the release layer may be set according to the purpose of use, and is not particularly limited, but preferably, the range in which the release layer after curing is 0.2 to 2.0 μm is good. More preferably, it is 0.3-1.5 micrometers, More preferably, it is 0.3-1.0 micrometers. When the thickness of the release layer is 0.2 μm or more, the curability of the energy ray-curable copolymerized acrylic resin is good and the elastic modulus of the release layer is improved, which is preferable because good release performance is obtained. Further, when the thickness is 2.0 μm or less, curling is unlikely to occur even when the thickness of the release film is reduced, and thus it is preferable because the runability defect does not occur in the process of molding and drying the ceramic green sheet.

  The release film of the present invention preferably has high surface smoothness of the release layer. Therefore, it is preferable that the area | region surface average roughness (Sa) of the mold release layer surface is 7 nm or less. Further, it is more preferable that the above-mentioned Sa is satisfied, and the maximum projection height (P) on the surface of the releasing layer is 100 nm or less. Furthermore, the area surface average roughness (Sa) is preferably 5 nm or less, and at the same time the maximum projection height (P) is particularly preferably 80 nm or less. If the area surface roughness (Sa) is 7 nm or less, defects such as pinholes do not occur at the time of forming the ceramic green sheet, which is preferable because the yield is good. If the above-mentioned Sa is satisfied and the maximum projection height (P) on the surface of the releasing layer is 100 nm or less, the possibility of causing a pinhole defect is further reduced, which is preferable. It can be said that the smaller the area surface average roughness (Sa) is, the better, but it may be 0.1 nm or more, and may be 0.3 nm or more. The smaller the maximum projection height (P), the better, but it may be 1 nm or more, or 3 nm or more.

Surface free energy of the release layer surface of the release layer film of the present invention is preferably 18 mJ / ^{m 2} or more 40 mJ / ^{m 2} or less. More preferably, the 20 mJ / ^{m 2} or more 35 mJ / ^{m 2} or less. When it is 18 mJ / m < ² > or more, when a ceramic slurry is coated, it is hard to generate | occur | produce repelling easily and it can coat uniformly, and it is preferable. Moreover, if it is 40 mJ / m < ² > or less, there is no possibility that the mold release property of a ceramic green sheet may fall, and it is preferable. By setting it as the said range, there is no repelling at the time of coating, and the release film excellent in release property can be provided.

  The release film of the present invention is preferable because the corrosion resistance of the release layer by the organic solvent at the time of ceramic sheet processing or electrode printing, such as toluene, can be suppressed as the solvent resistance is higher. The solvent resistance can be confirmed by evaluating the difference in the surface state of the release layer before and after the release film is immersed in the organic solvent. As the organic solvent, it is preferable to use toluene that is used for general ceramic slurry and conductive paste, assuming processing of ceramic green sheets and electrode printing. As an example of the method of evaluating the surface state of the release layer, evaluation by a contact angle is mentioned, and the smaller the change in contact angle on the surface of the release layer before and after immersion in toluene, the better.

  The type of liquid drop used to measure the contact angle is not particularly limited, but water, bromonaphthalene, ethylene glycol, etc. can be suitably used, but the difference in the surface state of the release layer should be more clearly seen. Most preferably, diiodomethane is used.

When using diiodomethane as Eki摘used to measure contact angle at room temperature diiodomethane contact angle theta ₁ and the release film of the release layer surface in toluene, the contact angle of the release layer surface after immersion 5 minutes theta _The smaller the value of the difference of ₂ (θ ₁ -θ ₂ ), the better the solvent resistance of the surface of the release layer, which is preferable. Specifically, the absolute value is preferably 3.0 ° or less, more preferably 2.0 ° or less, and most preferably 1.0 ° or less. The erosion of the release layer by the organic solvent at the time of ceramic green sheet processing or electrode printing is suppressed as it is 3.0 degrees or less, and there is no possibility that the increase in exfoliation power or the uniformity of exfoliation will be impaired. The difference (θ ₁ -θ ₂ ) between the diiodomethane contact angle θ ₁ on the release layer surface and the contact angle θ ₂ of the release layer surface after immersion of the release film in toluene for 5 minutes at room temperature is most preferably 0 ° The absolute value may be 0.05 ° or more, or 0.1 ° or more.

  It is preferable that the release film of the present invention has less curl. When the curl is small, the uniformity at the time of coating and molding of the ceramic green sheet is deteriorated, and there is no possibility that the film thickness of the ceramic green sheet becomes nonuniform, which is preferable. Moreover, there is no possibility that printing accuracy may fall in an electrode printing process, and it is preferable. Furthermore, at the time of roll conveyance, the tension of the release film is less likely to be different at the film central portion and the end portion, and there is no possibility that the appearance quality such as meandering or winding deviation during conveyance is deteriorated.

  The release film of the present invention preferably has a peeling force of 0.5 mN / mm or more and 4.0 mN / mm or less when peeling the ceramic green sheet. More preferably, they are 0.8 mN / mm or more and 3.0 mN / mm or less. When the peeling force is 0.5 mN / mm or more, there is no possibility that the peeling force is too light and the ceramic green sheet may float during transportation, which is preferable. When the peeling force is 4.0 mN / mm or less, there is no possibility that the ceramic green sheet is damaged at the time of peeling, which is preferable.

  The release film of the present invention preferably has a high crosslinking density and a high elastic modulus. When the elastic modulus is high, deformation of the release layer at the time of peeling is small, and peeling is possible with low uniform force, which is preferable. The elastic modulus can be evaluated by the degree of scratching when the release layer surface is rubbed with steel wool. The degree of scratching can be evaluated by the number of scratches that occur when the release layer is rubbed with steel wool.

(Method of forming release layer)
In the present invention, the method for forming the releasing layer is not particularly limited, and a coating liquid in which a releasing resin is dissolved or dispersed is spread on one surface of the polyester film of the substrate by coating etc. The method of making it harden | cure after removing by drying is used.

It is preferable that the drying temperature of solvent drying in the case of apply | coating the release layer of this invention on a base film by solution application is 50 degreeC or more and 100 degrees C or less, and is 60 degrees C or more and 95 degrees C or less More preferable. The drying time is preferably 30 seconds or less and more preferably 20 seconds or less. Furthermore, after solvent drying, it is preferable to irradiate an active energy ray to advance the curing reaction. As the active energy ray used at this time, ultraviolet rays, electron beams, X-rays and the like can be used, but ultraviolet rays are preferred because they are easy to use. Preferably 30~300mJ / cm ² in quantity as the amount of ultraviolet rays to be irradiated, more preferably 30~200mJ / cm ^2. By setting it to 30 mJ / cm ² or more, curing of the resin proceeds sufficiently, and by setting it to 300 mJ / cm ² or less, the processing speed can be improved, so that it is possible to economically form a release film, which is preferable. .

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

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

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

(Ceramic green sheet and ceramic capacitor)
In general, a laminated ceramic capacitor has a rectangular parallelepiped ceramic body. Inside the ceramic body, first internal electrodes and second internal electrodes are alternately provided along the thickness direction. The first inner 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 inner electrode is electrically connected to the first outer electrode at the first end face. The second inner 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 inner electrode is electrically connected to the second outer electrode at the second end face.

  The release film for producing a ceramic green sheet of the present invention is used to produce such a multilayer ceramic capacitor. For example, it is manufactured as follows. First, using the release film of the present invention as a carrier film, a ceramic slurry for forming a ceramic body is applied and dried. As for the thickness of the ceramic green sheet, a very thin product of 0.2 to 1.0 μm has been required. A conductive layer for forming a first or second internal electrode is printed on the coated and dried ceramic green sheet. The ceramic green sheet, the ceramic green sheet on which the conductive layer for forming the first internal electrode is printed, and the ceramic green sheet on which the conductive layer for forming the second internal electrode is printed are appropriately laminated and pressed. Thus, a mother laminate is obtained. The mother laminate is divided into a plurality of pieces to prepare a green ceramic body. A ceramic body is obtained by firing a green ceramic body. Thereafter, the laminated ceramic capacitor can be completed by forming the first and second external electrodes.

  EXAMPLES Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited by these examples. The characteristic values used in the present invention were evaluated using the following method.

(Base film thickness)
Using a Millitron (electronic micro indicator), 4 pieces of 5 cm square samples were cut out from any 4 parts of the film to be measured, and 5 pieces of each sample (20 pieces in total) were measured to obtain an average value as a thickness.

(Inherent viscosity of polyester resin (dl / g))
It measured at 30 degreeC using the mixed solvent of phenol (60 mass%) and 1,1,2,2- tetrachloroethane (40 mass%) as a solvent based on JISK 7367-5: 2000.

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

(Area surface roughness Sa, maximum projection height P)
It is a value measured under the following conditions using a non-contact surface shape measurement system (VertScan R550H-M100, manufactured by Ryoka System Co., Ltd.). The area surface average roughness (Sa) was an average value of 5 measurements, and the maximum projection height (P) was 7 measurements, and the maximum value of 5 values excluding the maximum value and the minimum value was used.
(Measurement condition)
・ Measurement mode: WAVE mode ・ Objective lens: 10 times ・ 0.5 × Tube lens ・ Measurement area 936μm × 702μm
(Analysis conditions)
-Face correction: 4th order correction-Interpolation: Complete interpolation

(Surface free energy)
Water (droplet amount of 1.8 μL) was applied to 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. Droplets of diiodomethane (liquid suitable amount: 0.9 μL) and ethylene glycol (liquid suitable amount: 0.9 μL) were prepared, and their contact angles were measured. As the contact angle, a contact angle after 10 seconds after dropping each liquid onto the release film was adopted. The contact angle data of water, diiodomethane and ethylene glycol obtained by the above method are calculated from “Kitazaki-Hata” theory to determine the dispersion component γsd of the surface free energy of the release film, the polar component γsp and the hydrogen bond component γsh The sum of each component was taken as the surface free energy γs. This calculation was performed using analysis software in the contact angle meter software (FAMAS).

(Contact angle after immersion in toluene)
The release film used for the measurement was cut into a size of 5 cm × 5 cm, and immersed in a glass tray containing 30 mL of toluene having a liquid temperature of 25 ° C. for 5 minutes with the release surface down. The dipped release film was taken out, air-dried with the release surface facing upward for 15 minutes, and then vacuum-dried at 25 ° C. overnight. The diiodomethane contact angle of the release film after toluene immersion obtained in this way was measured by the same method as the method of measuring the contact angle.

(Evaluation of contact angle change)
When the diiodomethane contact angle of the initial release layer surface before toluene immersion is measured by the above method is θ ₁ , and the diiodomethane contact angle of the release layer surface after toluene immersion is θ ₂ , θ ₁ -θ ₂ The absolute value was taken as the value of the contact angle change before and after immersion in toluene. The change of the contact angle was evaluated on the basis of the following criteria.
:: | θ ₁ −θ ₂ | <1.0 °
○: 1.0 ° ≦ | θ ₁ −θ ₂ | <2.0 °
Δ: 2.0 ° ≦ | θ ₁ −θ ₂ | ≦ 3.0 °
×: | θ ₁ −θ ₂ |> 3.0

(Evaluation of coatability of ceramic slurry)
The composition consisting of the following materials was stirred and mixed, and dispersed with zirconia beads of 0.5 mm in diameter for 30 minutes using a bead mill to prepare a ceramic slurry.
Toluene 76.3 parts by mass Ethanol 76.3 parts by mass Barium titanate (HPBT-1 manufactured by Fuji Titanium Co., Ltd.) 35.0 parts by mass Polyvinyl butyral 3.5 parts by mass (S-Rec (registered trademark) BM-S manufactured by Sekisui Chemical Co., Ltd. )
Next, 1.8 parts by mass of DOP (dioctyl phthalate) is applied to the release surface of the release film sample using an applicator so that the ceramic green sheet after drying is 0.8 μm and dried at 90 ° C. for 2 minutes, The coatability was evaluated based on the following criteria.
○: No coating was done and coating was possible on the entire surface.
Fair: There is some repelling at the coating end, but coating is possible on almost the entire surface.
X: There are many repellings other than the coating edge part, and it has not coated on the whole surface.

(Pinhole evaluation of ceramic green sheet)
After molding the ceramic green sheet by the same method as the evaluation of the coating property of the ceramic slurry, the release film was peeled to obtain a ceramic green sheet.
In the central region of the film width direction of the obtained ceramic green sheet, light is applied from the opposite surface of the ceramic slurry application surface in the range of 25 cm ² , and the occurrence of pinholes where light is seen to be transmitted is observed. It judged visually. The measurement was performed 5 times and the average value was adopted.
:: No occurrence of pinholes ○: Almost no occurrence of pinholes (estimate: no more than 2 pinholes per measurement area)
:: Occurrence of pinholes (estimated: 3 or more, 5 or less pinholes per measurement area)
X: There are many pinholes (including non-removable)

(Evaluation of peelability of ceramic green sheet)
The composition consisting of the following materials was stirred and mixed, and dispersed with zirconia beads of 0.5 mm in diameter 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 Co., Ltd.) 64.8 parts by mass Polyvinyl butyral 6.5 parts by mass (S-Rec (registered trademark) BM-S manufactured by Sekisui Chemical Co., Ltd. )
DOP (dioctyl phthalate) 3.3 parts by mass Then, an applicator was used to apply a thickness of 10 μm to the release surface of the release film sample, and dried for 2 minutes at 90 ° C. The sheet was molded on a release film. The obtained release film with a ceramic green sheet was cut into a width of 30 mm and a length of 80 mm, and used as a sample for measurement of peel force. After removing electricity using an electric discharge machine (manufactured by KEYENCE CORPORATION, SJ-F020), using a peeling tester (VPA-3 manufactured by Kyowa Interface Science), peeling angle 90 °, peeling temperature 25 ° C., peeling speed 10 m / It peeled in min. As a peeling direction, a double-sided adhesive tape (Nitto Denko Co., Ltd., No. 535A) is stuck on a SUS plate attached to a peeling tester, and a release film is formed by bonding the ceramic green sheet side to the double-sided tape on it. Were fixed and peeled off in the form of pulling the release film side. The average value of the peeling force of 20 mm-70 mm of peeling distances was computed among the obtained measured values, and the value was made into peeling force. The measurement was performed a total of five times, and the value of the average value of the peeling force was adopted and evaluated. From the numerical value of the peeling force obtained, it was judged according to the following criteria.
◎: Peeling was possible with a very light force of 2.0 mN / mm or less.
:: Peeling force was greater than 2.0 mN / mm, and peeling was possible with a relatively light force of 3.0 mN / mm or less.
Fair: Peeling force was greater than 3.0 mN / mm, and peeling was possible with a light force of 4.0 mN / mm or less.
X: Peeling force required a force greater than 4.0 mN / mm.

(Curl evaluation of release film)
The release film sample was cut into a size of 10 cm × 10 cm, and heat treatment was performed in a hot air oven at 90 ° C. for 1 minute so that no tension was applied to the release film. Thereafter, the sample was taken out of the oven and cooled to room temperature, and then the release film sample was placed on white fine paper with the release surface facing up, and the height of the part floating from the upper white paper was measured. At this time, the height of the portion that floated the largest from the upper white paper was taken as the measurement value. The curling was evaluated based on the following criteria.
◎: The curl was 1 mm or less and hardly curled ○: The curl was larger than 1 mm and 3 mm or less, and a slight curl was observed.
Fair: The curl was larger than 3 mm and 10 mm or less, and curl was observed.
X: The curl was larger than 10 mm.

(Silicone transferability)
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 (S-LEC BM-S manufactured by Sekisui Chemical Co., Ltd.) 10.0 parts by mass Then, the release surface of the obtained release film sample is dried using an applicator. The PVB sheet is coated so as to be 10 μm and dried at 90 ° C. for 2 minutes, and then the release film is peeled off, and the surface (release layer) of the peeled PVB sheet to which the release film was in contact The Si strength of the release layer of the release film before coating was measured with a fluorescent X-ray apparatus (ZSX Primus 2 manufactured by Rigaku) to quantify the amount of silicone transferred. The measurement conditions of the fluorescent X-ray apparatus were as follows.
Analysis line: Si-KA Target: Rh 4.0 kW
Tube voltage: 50kV, tube current: 60mA
Filter: OUT, Attenuator: 1/1, Slit: S4, Spectroscopic crystal: PET
Detector: PC, PHA condition: 100 (lower limit)-300 (upper limit)
Measurement diameter: 30 mm, atmosphere: vacuum Transfer amount of silicone, Si strength of release surface of release film before applying PVB sheet to Si (front), release film after applying and peeling PVB sheet A value obtained by subtracting Si (after) from Si (before) as Si (after) is taken as a silicone transfer amount. From the numerical value of the silicone transfer amount obtained, it was judged according to the following criteria.
:: 0.04 kcps or less ○: greater than 0.04 kcps, 0.10 kcps or less Δ: greater than 0.10 kcps, 0.20 kcps or less ×: 0.20 kcps or more

(Evaluation of scratch resistance)
A steel wool (Nippon Steel Wool Co., Ltd., Bonstar (registered trademark) No. 0000) was attached to a metal pedestal of weight 700 g and size 700 mm ² to prepare a steel wool evaluation jig. Using this jig, the five-reciprocal release surface was rubbed while applying a load of 200 g in such a manner that the release surface of the release film was in contact with the steel wool. An area of 2 × 2 cm at the center of the rubbed surface was observed under transmission of a fluorescent lamp to evaluate the number of scratches visually observed. The number of flaws was judged and evaluated according to the following criteria.
:: Number of flaws ≦ 1 piece ○: 1 piece <number of flaws ≦ 10 pieces △: 10 pieces <number of flaws ≦ 20 pieces ×: 20 pieces <number of flaws

(Method of measuring weight average molecular weight)
The analysis was performed using gel permeation chromatography (manufactured by Tosoh Corporation HLC-8220 GPC) under the following conditions, and calculated by polystyrene conversion.
Column: Shodex (registered trademark) KF-805L
Medium: tetrahydrofuran,
Flow rate: 1.0 mL / min,
Sample concentration: 1.5 mg / ml,
Injection volume: 300 μL,
Column temperature: 40 ° C

(Preparation of polyethylene terephthalate pellets (PET (I)))
As an esterification reaction apparatus, a continuous esterification reaction apparatus was used which was composed of a three-stage complete mixing tank having a stirrer, a partial condenser, a raw material feed port and a product outlet. TPA (terephthalic acid) is 2 tons / hour, EG (ethylene glycol) is 2 moles with respect to 1 mole of TPA, antimony trioxide is produced in an amount such that 160 ppm of Sb atoms are formed with respect to PET, and these slurries are ester The reaction mixture was continuously fed to the first esterification reactor of the esterification reactor, and reacted at 255 ° C. for 4 hours at an average residence time under normal pressure. Then, the reaction product in the first esterification reaction vessel is continuously taken out of the system, supplied to the second esterification reaction vessel, and distilled from the first esterification reaction vessel in the second esterification reaction vessel. The EG solution contains 8% by weight of EG to the produced PET, and further contains an EG solution containing magnesium acetate tetrahydrate in an amount of 65 ppm of Mg atoms to the produced PET, and 40 ppm of P atoms to the produced PET The EG solution containing the following amount of TMPA (trimethyl phosphate) was added, and the reaction was carried out at 260.degree. C. under an atmospheric pressure for an average residence time of 1 hour. Then, the reaction product of the second esterification reaction vessel is continuously taken out of the system, supplied to the third esterification reaction vessel, and 39 MPa (400 kg / cm ² ) using a high pressure disperser (manufactured by Nippon Seiki Co., Ltd.) 0.2% by mass of porous colloidal silica with an average particle size of 0.9 μm dispersed with an average pressure of 5 passes and an average particle of 1% by mass per ammonium carbonate of an ammonium salt of polyacrylic acid While adding 0.4 mass% of synthetic calcium carbonate having a diameter of 0.6 μm as an EG slurry of 10% each, the reaction was carried out at 260 ° C. at an average residence time of 0.5 hours under normal pressure. The esterification reaction product generated in the third esterification reaction vessel was continuously supplied to a three-stage continuous polycondensation reaction apparatus to conduct polycondensation, and a 95% cut diameter sintered a 20 μm stainless steel fiber After filtration with a filter, it was ultrafiltered and extruded in water, and after cooling it was cut into chips to obtain PET chips with an intrinsic viscosity of 0.60 dl / g (hereinafter abbreviated as PET (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 manufacture of the above-mentioned PET chip, a PET chip having an intrinsic viscosity of 0.62 dl / g containing no particles such as calcium carbonate and silica was obtained (hereinafter referred to as PET (II)).

(Manufacture of laminated film X1)
After drying, these PET chips are melted at 285 ° C., melted at 290 ° C. by a separate melt extruder extruder, and a 95% cut diameter sintered filter of 15 μm stainless steel fibers, 95% cut diameter Two-stage filtration of a filter made of sintered 15 μm stainless steel particles is carried out and merged in a feed block to make PET (I) a surface layer B (reciprocal side layer), PET (II) a surface Layer A (release surface side layer) is laminated, extruded in a sheet shape at a speed of 45 m / min (casting), and electrostatically adhered and cooled on a casting drum at 30 ° C. by an electrostatic adhesion method. An unstretched polyethylene terephthalate sheet having an intrinsic viscosity of 0.59 dl / g was obtained. The layer ratio was adjusted to be PET (I) / (II) = 60% / 40% in calculation of the discharge amount of each extruder. Next, this unstretched sheet was heated by an infrared heater and then stretched 3.5 times in the longitudinal direction at a roll temperature of 80 ° C. due to the speed difference between the rolls. Thereafter, it was introduced into a tenter and stretched 4.2 times in the transverse direction at 140 ° C. It was then heat treated at 210 ° C. in the heat setting zone. Thereafter, the film was subjected to a relaxation treatment at 2.3 ° C. in the horizontal direction at 170 ° C. to obtain a 31 μm-thick biaxially stretched polyethylene terephthalate film X1. The Sa of the surface layer A of the obtained film X1 was 2 nm, and the Sa of the surface layer B was 28 nm.

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

(Production of laminated film X3)
A 25 μm thick polyester film (Toyobo ester (registered trademark) film E5101, manufactured by Toyobo Co., Ltd.) was used. E5101 has a configuration in which inorganic particles are also contained in the surface layer A of the two-layer structure. The Sa of the surface layer A was 24 nm, and the Sa of the surface layer B was 24 nm.

(Polymerization of Precursor Acrylic Copolymer 1a)
Add 10 g of methyl methacrylate, 10 g of methacryloyl modified polydimethylsiloxane at one end (product made by JNC, product name: FM0721, molecular weight 5,000), 80 g of glycidyl methacrylate, 2 g of dodecyl mercaptan and 200 g of methyl isobutyl ketone (MIBK) It heated up to 60 degreeC under airflow. Thereafter, a total of 2 g of AIBN was added, and the mixture was stirred for 6 hours to obtain a precursor acrylic copolymer 1a. The weight average molecular weight was 10,000, and the solid content concentration was 35% by mass.

(Synthesis of energy ray-curable copolymerized acrylic resin 1b)
Next, after heating to 90 ° C. in an air atmosphere, 0.1 g of p-methoxyphenol and 0.5 g of triphenylphosphine were added. After 5 minutes, 40.7 g of acrylic acid was dissolved in 76 g of MIBK and added dropwise over 30 minutes. During this time, the solution temperature was maintained at 90 to 100 ° C. Thereafter, the liquid temperature was raised to 110 ° C. and maintained at this temperature for 8 hours, and then returned to room temperature to obtain an energy ray-curable copolymerized acrylic resin 1b. The solid content concentration was 35% by mass, and the weight average molecular weight was 11,000.

(Polymerization of Precursor Acrylic Copolymer 2a)
Add 10 g of methyl methacrylate, 30 g of methacryloyl modified polydimethylsiloxane at one end (product name: X-22-174 ASX, product name: X-22-174 ASX, molecular weight 900), 60 g of glycidyl methacrylate, 2 g of dodecyl mercaptan and 200 g of methyl isobutyl ketone (MIBK) The temperature was raised to 60 ° C. under a nitrogen stream. Thereafter, a total of 2 g of AIBN was added and stirred for 6 hours to obtain a precursor acrylic copolymer 2a. The weight average molecular weight was 10,000, and the solid content concentration was 35% by mass.

(Synthesis of energy ray-curable copolymerized acrylic resin 2b)
Next, after heating to 90 ° C. in an air atmosphere, 0.1 g of p-methoxyphenol and 0.5 g of triphenylphosphine were added. After 5 minutes, 30.6 g of acrylic acid was dissolved in 58 g of MIBK and added dropwise over 30 minutes. During this time, the solution temperature was maintained at 90 to 100 ° C. Thereafter, the liquid temperature was raised to 110 ° C. and maintained at this temperature for 8 hours, and then returned to room temperature to obtain an energy ray-curable copolymerized acrylic resin 2 b. The solid content concentration was 35% by mass, and the weight average molecular weight was 11,000.

(Polymerization of Precursor Acrylic Copolymer 3a)
Add 10 g of methyl methacrylate, 1 g of methacryloyl modified polydimethyl siloxane at one end (product made by JNC, product name: FM0721, molecular weight 5,000), 89 g of glycidyl methacrylate, 2 g of dodecyl mercaptan and 200 g of methyl isobutyl ketone (MIBK). It heated up to 60 degreeC under airflow. Thereafter, a total of 2 g of AIBN was added and stirred for 6 hours to obtain a precursor acrylic copolymer 3a. The weight average molecular weight was 10,000, and the solid content concentration was 35% by mass.

(Synthesis of energy ray-curable copolymerized acrylic resin 3b)
Next, after heating to 90 ° C. in an air atmosphere, 0.1 g of p-methoxyphenol and 0.5 g of triphenylphosphine were added. After 5 minutes, 45.4 g of acrylic acid was dissolved in 85 g of MIBK and added dropwise over 30 minutes. During this time, the solution temperature was maintained at 90 to 100 ° C. Thereafter, the liquid temperature was raised to 110 ° C. and maintained at this temperature for 8 hours, and then returned to room temperature to obtain an energy ray-curable copolymerized acrylic resin 3 b. The solid content concentration was 35% by mass, and the weight average molecular weight was 11,000.

(Polymerization of Precursor Acrylic Copolymer 4a)
Add one-end methacryloyl modified polydimethylsiloxane (manufactured by JNC, product name: FM0721, molecular weight 5,000) 3 g, glycidyl methacrylate 97 g, dodecyl mercaptan 2 g, methyl isobutyl ketone (MIBK) 200 g, internal temperature under nitrogen stream 60 ° C. The temperature rose to the end. Thereafter, a total of 2 g of AIBN was added, and the mixture was stirred for 6 hours to obtain a precursor acrylic copolymer 4a. The weight average molecular weight was 10,000, and the solid content concentration was 35% by mass.

(Synthesis of energy ray-curable copolymerized acrylic resin 4b)
Next, after heating to 90 ° C. in an air atmosphere, 0.1 g of p-methoxyphenol and 0.5 g of triphenylphosphine were added. After 5 minutes, 49.4 g of acrylic acid was dissolved in 93 g of MIBK and added dropwise over 30 minutes. During this time, the solution temperature was maintained at 90 to 100 ° C. Thereafter, the liquid temperature was raised to 110 ° C. and maintained at this temperature for 8 hours, and then returned to room temperature to obtain an energy ray-curable copolymerized acrylic resin 4 b. The solid content concentration was 35% by mass, and the weight average molecular weight was 11,000.

(Polymerization of Precursor Acrylic Copolymer 5a)
Add 10 g of methyl methacrylate, 10 g of methacryloyl modified polydimethylsiloxane at one end (product made by JNC, product name: FM 0721, molecular weight 5,000), 80 g of glycidyl methacrylate, 1.5 g of dodecyl mercaptan and 200 g of methyl isobutyl ketone (MIBK) Was heated to 55.degree. C. under a nitrogen stream. Thereafter, a total of 1.5 g of AIBN was added and stirred for 10 hours to obtain precursor acrylic copolymer 5a. The weight average molecular weight was 50,000, and the solid content concentration was 35% by mass.

(Synthesis of energy ray-curable copolymerized acrylic resin 5b)
Next, after heating to 90 ° C. in an air atmosphere, 0.1 g of p-methoxyphenol and 0.5 g of triphenylphosphine were added. After 5 minutes, 40.7 g of acrylic acid was dissolved in 76 g of MIBK and added dropwise over 30 minutes. During this time, the solution temperature was maintained at 90 to 100 ° C. Thereafter, the liquid temperature was raised to 110 ° C. and maintained at this temperature for 8 hours, and then returned to room temperature to obtain an energy ray-curable copolymerized acrylic resin 5b. The solid content concentration was 35% by mass, and the weight average molecular weight was 52,000.

(Polymerization of Precursor Acrylic Copolymer 6a)
Add 30 g of methyl methacrylate, 10 g of methacryloyl modified polydimethylsiloxane at one end (product made by JNC, product name: FM0721, molecular weight 5,000), 60 g of glycidyl methacrylate, 2 g of dodecyl mercaptan and 200 g of methyl isobutyl ketone (MIBK) It heated up to 60 degreeC under airflow. Thereafter, a total of 2 g of AIBN was added, and the mixture was stirred for 6 hours to obtain a precursor acrylic copolymer 6a. The weight average molecular weight was 10,000, and the solid content concentration was 35% by mass.

(Synthesis of energy ray-curable copolymerized acrylic resin 6b)
Next, after heating to 90 ° C. in an air atmosphere, 0.1 g of p-methoxyphenol and 0.5 g of triphenylphosphine were added. After 5 minutes, 30.7 g of acrylic acid was dissolved in 58 g of MIBK and added dropwise over 30 minutes. During this time, the solution temperature was maintained at 90 to 100 ° C. Thereafter, the liquid temperature was raised to 110 ° C. and maintained at this temperature for 8 hours, and then returned to room temperature to obtain an energy ray-curable copolymerized acrylic resin 6 b. The solid content concentration was 35% by mass, and the weight average molecular weight was 11,000.

(Polymerization of Precursor Acrylic Copolymer 7a)
20 g of methyl methacrylate, 80 g of glycidyl methacrylate, 2 g of dodecyl mercaptan and 200 g of methyl isobutyl ketone (MIBK) were added, and the internal temperature was raised to 60 ° C. under a nitrogen stream. Thereafter, a total of 2 g of AIBN was added and stirred for 6 hours to obtain a precursor acrylic copolymer 7a. The weight average molecular weight was 10,000, and the solid content concentration was 35% by mass.

(Synthesis of energy ray-curable copolymerized acrylic resin 7b)
Next, after heating to 90 ° C. in an air atmosphere, 0.1 g of p-methoxyphenol and 0.5 g of triphenylphosphine were added. After 5 minutes, 40.7 g of acrylic acid was dissolved in 76 g of MIBK and added dropwise over 30 minutes. During this time, the solution temperature was maintained at 90 to 100 ° C. Thereafter, the liquid temperature was raised to 110 ° C. and maintained at this temperature for 8 hours, and then returned to room temperature to obtain an energy ray-curable copolymerized acrylic resin 7 b. The solid content concentration was 35% by mass, and the weight average molecular weight was 11,000.

Example 1
A coating solution of the composition shown below is coated on the surface layer A of the laminated film X1 using a wire bar so that the thickness of the release layer after drying is 0.9 μm and dried at 90 ° C. for 30 seconds A release film for producing a ceramic green sheet was obtained by irradiating ultraviolet light with an accumulated light quantity of 70 mJ / cm ² using an ultraviolet irradiator (LC6B, H bulb manufactured by Heraeus). The ceramic slurry is applied to the obtained release film, and the release layer surface roughness, surface free energy, coatability, pin hole, peelability, curl, scratch resistance, silicone migration, solvent resistance As a result of evaluation, good evaluation results were obtained.
Methyl ethyl ketone 10.48 parts by mass Isopropyl alcohol 31.42 parts by mass Energy ray-curable copolymerized acrylic resin 1b 57.10 parts by mass (solid content: 35% by mass)
Photopolymerization initiator 1.00 parts by mass (Omnirad 127, manufactured by IGM Resins)

(Examples 2 to 6)
A release film for producing an ultrathin ceramic green sheet was obtained in the same manner as in Example 1 except that the energy ray-curable copolymerized acrylic resin was changed to one described in Table 1.

(Examples 7, 8)
A release film for producing an ultrathin ceramic green sheet was obtained in the same manner as in Example 4 except that the thickness of the release layer was changed to the value described 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 was changed to the laminated film X2.

(Example 10)
A coating solution of the composition shown below is coated on the surface layer A of the laminated film X1 using a wire bar so that the thickness of the release layer after drying is 0.9 μm and dried at 140 ° C. for 30 seconds A release film for producing a ceramic green sheet was obtained by irradiating ultraviolet light with an accumulated light quantity of 70 mJ / cm ² using an ultraviolet irradiator (LC6B, H bulb manufactured by Heraeus).
Methyl ethyl ketone 13.25 parts by mass Isopropyl alcohol 39.75 parts by mass Energy ray-curable copolymerized acrylic resin 4b 40.00 parts by mass (solid content: 35% by mass)
Hexamethoxymethylmelamine 6.00 parts by mass (solid content 100%, manufactured by Tokyo Chemical Industry Co., Ltd.)
0.40 parts by mass of 4-methylbenzoic acid (solid content 100%, manufactured by Tokyo Chemical Industry Co., Ltd.)
Photopolymerization initiator (Omnirad 127, manufactured by IGM Resins) 0.60 parts by mass

(Comparative example 1)
A release film for producing an ultrathin ceramic green sheet was obtained in the same manner as in Example 1 except that the energy ray-curable copolymerized acrylic resin was changed to 7b described in Table 1. The obtained release film used an energy ray-curable copolymerized acrylic resin having no polyorganosiloxane in its molecule, and therefore could not be peeled off.

(Comparative example 2)
A release film for producing an ultrathin ceramic green sheet was prepared in the same manner as in Example 4 except that the film thickness of the release layer was 0.2 μm using the laminate film X3 as the base film. Obtained. The obtained release film had a large surface roughness of the release layer, and pinholes were generated in the ceramic green sheet. Moreover, the ceramic green sheet peeling force was heavy, and evaluation of silicone migration and solvent resistance was also bad.

(Comparative example 3)
A release film for producing an ultrathin ceramic green sheet was obtained in the same manner as in Example 1 except that the coating liquid had the composition shown below.
Methyl ethyl ketone 19.70 parts by mass Isopropyl alcohol 59.10 parts by mass Dipentaeristole hexaacrylate 20.00 parts by mass (A-DPH, manufactured by Shin-Nakamura Chemical Co., Ltd., solid content 100%)
Acryloyl group-containing polyether-modified polydimethylsiloxane 0.20 parts by mass (BYK UV-3500, solid content by Big Chemie Japan 100%)
Photopolymerization initiator 1.00 parts by mass (Omnirad 127, manufactured by IGM Resins)
The obtained release film had a large surface free energy and a heavy peeling force. In addition, the curing shrinkage of the release layer was large, curling occurred, and silicone migration and solvent resistance were also poor.

(Comparative example 4)
A release film for producing an ultrathin ceramic green sheet was obtained in the same manner as in Example 1 except that the coating liquid had the composition shown below.
Methyl ethyl ketone 19.75 parts by mass Isopropyl alcohol 59.25 parts by mass Acrylate modified polydimethylsiloxane with both ends 20.00 parts by mass (X-22-2445, manufactured by Shin-Etsu Chemical Co., Ltd., solid content 100%)
Photopolymerization initiator 1.00 parts by mass (Omnirad 127, manufactured by IGM Resins)
The obtained release film had poor wettability of the polydimethylsiloxane to the base film, was aggregated on the surface of the base film, and had a large surface roughness. In addition, the surface free energy was small, repelling occurred when the ceramic slurry was applied, and pinholes occurred in the ceramic green sheet. In addition, the scratch resistance, the solvent resistance, the silicone migration were also bad, and the peeling force was heavy.

(Comparative example 5)
Using a wire bar, apply a coating solution of the composition shown below on the surface layer A of the laminated film X1 so that the film thickness after drying is 0.6 μm, and then dry at 160 ° C. for 15 seconds Thus, a release film for producing an ultrathin ceramic green sheet was obtained.
Methyl ethyl ketone 33.00 parts by mass Toluene 33.00 parts by mass Thermosetting addition type silicone 33.30 parts by mass (KS-847H, manufactured by Shin-Etsu Silicone Co., Ltd., solid content 30% by mass)
Platinum catalyst 0.70 parts by mass (CAT-PL-50T, manufactured by Shin-Etsu Chemical Co., Ltd.)
The obtained release film had low surface free energy, repelling occurred when the ceramic slurry was applied on the release film, and pinholes were generated in the formed ceramic green sheet. In addition, scratch resistance, solvent resistance, silicone migration was also bad.

  According to the release film for producing a ceramic green sheet of the present invention, compared to the conventional release film for producing a ceramic green sheet, the smoothness of the surface of the release layer is excellent, the crosslink density of the release layer is high, and the elasticity is high. Since curling is also suppressed despite the rate, even when an ultra-thin ceramic green sheet having a thickness of 1 μm or less is molded, defects such as pinholes are less, making it possible to manufacture a ceramic green sheet excellent in releasability.

Claims (6)

  A release film in which a release layer of 0.2 to 2.0 μm is laminated on at least one surface of a polyester film directly or through another layer, and the area surface roughness (Sa) of the release layer surface is 7 nm The coating film containing at least an energy ray-curable copolymerized acrylic resin having a weight average molecular weight of 2000 to 100,000 having a (meth) acryloyl group and a polyorganosiloxane group in one molecule is cured. Release film for producing ceramic green sheets.   The release layer contains an energy ray-curable resin component and a polyorganosiloxane component other than an energy ray-curable copolymerized acrylic resin having a molecular weight of 2,000 to 100,000 having a (meth) acryloyl group and a polyorganosiloxane group in one molecule. A release film for producing a ceramic green sheet according to claim 1.   An energy ray-curable copolymerized acrylic resin having a weight average molecular weight of 2,000 to 100,000 having a (meth) acryloyl group and a polyorganosiloxane group in one molecule, a monomer having a (meth) acryloyl group precursor and a polyorganosiloxane A compound having a (meth) acryloyl group is grafted to an acrylic copolymer (I) in which a plurality of types of monomers including at least a monomer having a group are copolymerized, and the acrylic copolymer (I) The mold release according to claim 1 or 2, wherein the amount of polyorganosiloxane group introduced is 0.01 to 10 mol% and the amount introduced by grafting of (meth) acryloyl group is 70 to 99.95 mol%. the film.   The laminated polyester film comprising at least two layers of polyester film, wherein the surface layer A on the side on which the release layer of the laminated polyester film is laminated is substantially free of inorganic particles. A release film for producing a ceramic green sheet according to any one of the above.   The surface layer B on the opposite side to the surface layer A of the laminated polyester film contains particles, the particles are silica particles and / or calcium carbonate particles, and the total content of particles relative to the total mass of the surface layer B The release film for producing a ceramic green sheet according to claim 4, which is 5000 to 15000 ppm.   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 1-5, Comprising: 0.2 micrometers-1 of the ceramic green sheet shape | molded A method of producing a ceramic green sheet having a thickness of 0 μm.