JP2022016465A - Release film for producing ceramic green sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a release film for producing a ceramic green sheet capable of molding a ceramic green sheet having less defects even in the case of an ultra-thin layer product having a thickness of 1 μm or less by providing a release layer which has excellent solvent resistance, small curing shrinkage and low peeling strength and is uniform while maintaining high smoothness of a release layer surface of a release film.

SOLUTION: There is provided a release film for producing a ceramic green sheet which is obtained by providing a release layer on at least one surface of a polyester film, wherein the release layer is obtained by curing a composition comprising a radically curable substance (a) having one or more radical curable functional groups selected from a (meth) acryloyl group and an alkenyl group, a thiol group-containing compound (b), a releasing agent (c) and a radical initiator (d).

SELECTED DRAWING: None

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to a mold release film for manufacturing a ceramic green sheet, and more specifically, a mold release film for manufacturing a ceramic green sheet that can suppress the occurrence of process defects such as pinholes and uneven thickness when manufacturing an ultrathin ceramic green sheet. It's about film.

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 such as polyvinyl acetal resin onto 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. Until now, when a ceramic green sheet is molded on the surface of the release layer of a polyester film, minute protrusions on the surface of the release layer affect the molded ceramic green sheet, and defects such as cissing and pinholes are likely to occur. There was a problem such as. Therefore, a method for realizing a release layer surface having excellent flatness has 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, a release film having a smoother release layer surface is desired. In addition, since the strength of the ceramic green sheet decreases as the film becomes thinner, it is also desired that the peeling force when the ceramic green sheet is peeled from the release film is low and uniform. 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 observed that the surface of the release layer becomes smooth by using a cured product of a composition containing a radical curable substance and a silicone-based component that reacts under irradiation with active energy rays as the release layer. It was issued. In addition, by increasing the elastic modulus of the release layer, when the ceramic green sheet is peeled off, the release layer becomes difficult to deform and it becomes difficult to follow the ceramic green sheet, so that it is also excellent in peelability. Issued (see, for example, Patent Documents 2 and 3).

However, according to the methods described in Patent Documents 2 and 3, there is a possibility that curing failure may occur due to the influence of oxygen inhibition due to the radical polymerization reaction. In particular, the silicone component segregated on the surface of the release layer is easily affected by oxygen inhibition, and when a silicone component having a radically polymerizable functional group is used, the curability of the surface of the release layer may deteriorate. .. As a result, the release layer is eroded by the organic solvent used during ceramic sheet processing and electrode printing, which causes heavy peeling and deterioration of peeling uniformity, which may cause defects in the ceramic green sheet during peeling.

Generally, radical polymerization in an inert gas atmosphere can prevent curing defects due to oxygen inhibition, but in this case, it is necessary to introduce special equipment and the processing speed is limited. Therefore, the productivity was poor and there was a problem in terms of cost. When manufacturing in the air, it is necessary to secure a sufficient film thickness of the release layer in order to prevent curing defects due to oxygen inhibition. However, since the radical curable substance has a large curing shrinkage, the release layer is formed. There is a problem that curling is likely to occur in the release film when the film thickness is thick. As a result, the accuracy of electrode printing after molding the ceramic green sheet may decrease, and a release film with less curl has been required. On the other hand, if the film thickness of the release layer is reduced in order to suppress curl, curing failure due to oxygen inhibition is likely to occur, the solvent resistance of the release layer deteriorates, and there is a risk of causing heavy peeling. ..

That is, using a photoradical curable substance that reacts by irradiation with active energy rays in the atmosphere, the release layer was cured to a thin thickness, specifically 0.5 μm or less, and further to 0.3 μm or less. In some cases, the radical curing reaction does not proceed efficiently due to the influence of oxygen inhibition, which may cause curing failure and damage the ceramic green sheet at the time of peeling.

Japanese Unexamined Patent Publication No. 2000-117899 International Publication No. 2013/145864 International Publication No. 2013/145865

The present invention has been made in the background of the problems of the prior art. That is, an object of the present invention is to provide a uniform release layer having excellent solvent resistance, low curing shrinkage, low peeling force, while maintaining high smoothness on the surface of the release layer of the release film. Therefore, an object of the present invention is to provide a release film for manufacturing a ceramic green sheet capable of molding a ceramic green sheet having few defects even in an ultrathin layer product having a thickness of 1 μm or less.

That is, the present invention has the following configuration.
1. 1. A release film having a release layer provided on at least one side of a polyester film, wherein the region surface average roughness (Sa) of the surface of the release layer is 7 nm or less, and the release layer is a (meth) acryloyl radical and A composition containing a radical curable substance (a) having one or more radical curable functional groups selected from alkenyl groups, a thiol group-containing compound (b), a mold release agent (c), and a radical initiator (d). A mold release film for manufacturing ceramic green sheets, which is made by curing radicals.
2. 2. The release film for producing a ceramic green sheet according to the first aspect above, wherein the thiol group-containing compound (b) does not have a radical curable functional group selected from a (meth) acryloyl group and an alkenyl group.
3. 3. The release film for producing a ceramic green sheet according to the first or second above, wherein the thiol group-containing compound (b) is a compound having two or more thiol groups in one molecule.
4. The difference (θ ₁ − θ ₂ ) between the diiodomethane contact angle θ ₁ on the surface of the release layer and the diiodomethane contact angle θ ₂ on the surface of the release layer after the release film is immersed in toluene is 3.0 ° or less as an absolute value. The release film for producing a ceramic green sheet according to any one of the above 1st to 3rd.
5. The release film for producing a ceramic green sheet according to any one of the above 1 to 4, wherein the release agent (c) is a compound containing a silicone component.
6. The release film for producing a ceramic green sheet according to any one of the above 1 to 4, wherein the release agent (c) is a compound containing a fluorine atom in the molecule.
7. The ceramic green sheet for producing the ceramic green sheet according to any one of 1 to 6 above, wherein the content of the thiol group-containing compound (b) is 1 to 30% by mass with respect to the total mass of the composition forming the release layer. Release film.
8. The polyester film has a surface layer A that does not substantially contain inorganic particles and a surface layer B on the opposite side that contains inorganic particles, and a release layer is provided on the surface layer A. The ceramic green sheet according to any one of 1 to 7 above, wherein the inorganic particles contained in B are silica particles and / or calcium carbonate particles, and the total amount of the inorganic particles is contained in the surface layer B at 5000 to 15000 ppm. Release film for manufacturing.
9. The release film for producing a ceramic green sheet according to any one of 1 to 8 above, wherein the release layer has a film thickness in the range of 0.01 μm or more and 0.5 μm or less.
10. (Meta) Radical curable substance (a) having one or more radical curable functional groups selected from acryloyl group and alkenyl group, thiol group-containing compound (b), mold release agent (c), radical initiator ( The method for producing a release film for producing a ceramic green sheet according to any one of 1 to 9 above, wherein the composition containing d) is cured in the air to form a release layer.
11. A method for producing a ceramic green sheet having a thickness of 0.2 μm to 1.0 μm, wherein the ceramic green sheet is produced by using the release film for producing the ceramic green sheet according to any one of the above 1 to 9. .. A method for manufacturing a ceramic capacitor, which employs the method for manufacturing a ceramic green sheet according to the eleventh item.

The release film for producing a ceramic green sheet of the present invention is excellent in solvent resistance and peelability because it can suppress oxygen inhibition, which is a problem peculiar to radical curable substances, and enhance the curability of the release layer surface. A release film can be provided. Further, since the curing shrinkage can be reduced, it is possible to provide a release film for manufacturing a ceramic green sheet, which suppresses the generation of curl and does not cause the occurrence of uneven thickness of the ceramic green sheet and the deterioration of electrode printing accuracy. can.

The present inventors provided a release layer directly on at least one surface of the biaxially oriented polyester film or via another layer, set the region surface average roughness (Sa) of the surface of the release layer to 7 nm or less, and set the release layer. The composition of the above is a cured composition containing a radical curable substance (a), a thiol group-containing compound (b), a release agent (c), and a radical initiator (d). However, we have found that it is possible to reduce the thickness of the release layer and provide a release film that does not generate curls. Hereinafter, the present invention will be described in detail.

(Polyester film)
The polyester constituting the polyester film used as the base material of 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 polyethylene terephthalate film is preferably 0.50 to 0.70 dl / g, more preferably 0.52 to 0.62 dl / g. When the intrinsic viscosity is 0.50 dl / g or more, it is preferable 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 is sufficiently vacuum dried.

The method for producing a polyester film in the present invention is not particularly limited, and a method generally used in the past can be used. For example, the polyester can be obtained by melting the polyester with an extruder, extruding it into a film, cooling it with a rotary cooling drum to obtain an unstretched film, and biaxially stretching the unstretched film. 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 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, processing process, and molding. 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 is preferably a laminated film having a surface layer A substantially free of inorganic particles on at least one surface. .. 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 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 A layer, the layer on the opposite surface thereof is the B layer, and the core layer other than these is the C layer, the layer structure in the thickness direction is the release layer / A /. B, or a laminated structure such as a release layer / A / C / B can be mentioned. As a matter of course, the C layer may have a plurality of layer configurations. Further, the surface layer B may not contain inorganic particles. In that case, in order to impart slipperiness for winding the film into a roll, it is preferable to provide a coat layer containing at least inorganic particles and a binder on the surface layer B.

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 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 that the inorganic particles are 50 ppm or less, preferably 10 ppm or less, and most preferably the detection limit or less when the inorganic elements are quantified by the optical X-ray analysis. It means the content. This means that even if inorganic particles are not actively added to the film, contamination components derived from foreign substances and stains attached to the raw material resin or the line or device 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 inorganic particles from the viewpoint of the slipperiness of the film and the ease with which air can escape. In particular, it is preferable to use silica particles and / or calcium carbonate particles. The content of the inorganic particles contained is preferably 5000 to 15000 ppm in total of the inorganic particles 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 B layer, inactive inorganic particles and / or heat-resistant organic particles other than silica and / or calcium carbonate can also be used, but from the viewpoint of transparency and cost, silica particles and / or It is more preferable to use calcium carbonate particles. Further, examples of the 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 inorganic 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 inorganic particles is 0.1 μm or more, the slipperiness of the release film is good, which is preferable. Further, when the average particle diameter is 2.0 μm or less, there is no possibility that pinholes are generated 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 is 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 raw material or the like in the surface layer A, which is the layer on which the release layer is provided, in order to prevent the mixing of inorganic particles such as lubricant.

The thickness ratio of the surface layer A, which is the layer on which the release layer is provided, is preferably 20% or more and 50% or less of the total thickness of the base film. When it is 20% or more, it is not easily affected by the particles contained in the surface layer B or the like from the inside of the film, and it is easy for the region surface average roughness Sa to satisfy the above range, which is preferable. When it is 50% or less of the thickness of 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 scraps or recycled raw materials for PET bottles can be used for the layers other than the surface layer A (surface layer B or the above-mentioned intermediate layer C). Even in this case, it is preferable that the type and amount of the lubricant contained in the B layer, 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.

(Release layer)
The release layer in the present invention is a radical curable substance (a) having a radical curable functional group selected from a (meth) acryloyl group and an alkenyl group, a thiol group-containing compound (b), a release agent (c), and the like. It is preferable that the composition containing the radical initiator (d) is cured. It can be added in addition to the resin and the additive as long as the function of the present invention is not impaired. Here, in the present invention, the radical curable substance (a) and the thiol group-containing compound (b) are considered to have changed in the structure of the compound in the state after being cured in the coating layer. Since it is extremely difficult to accurately represent and describe the structure itself, as described above, "a radical curable substance having a radical curable functional group whose release layer is selected from (meth) acryloyl and an alkenyl group (a). ), The thiol group-containing compound (b), the mold release agent (c), and the radical initiator (d) are cured. "

(Radical curable substance (a))
The radical curable substance (a) preferably has a radical curable functional group selected from a (meth) acryloyl group and an alkenyl group, and is a substance having at least two or more radical curable functional groups. May be used. Since the reaction rate of radical curing is very fast, the polymerization reaction proceeds instantly at the same time as the radical initiator is cleaved, and a coating film having a high crosslink density can be formed. By increasing the crosslink density of the release layer, the release layer can have a high elastic modulus, the release layer is less likely to be deformed when the ceramic green sheet is peeled off, and the ceramic green sheet can be peeled off uniformly with a low peeling force, which is preferable. The alkenyl group in the present invention refers to a group having 2 to 10 carbon atoms such as a vinyl group, an allyl group, a propenyl group and a hexenyl group.

The number of radical curable functional groups is preferably 3 or more, more preferably 6 or more, and even more preferably 9 or more, from the viewpoint of increasing the crosslink density. The number of functional groups is not particularly limited, but is preferably 20 or less. When the value is 20 or less, the intramolecular reaction is more likely to proceed than the cross-linking reaction between molecules, and the effect of efficiently improving the elastic modulus of the release layer is obtained, which is preferable.

Examples of the radical curable substance include acrylate, methacrylate, urethane acrylate, acrylamide, allyl compound, methallyl compound, maleimide compound and the like, but acrylate, methacrylate, urethane acrylate, allyl compound and methallyl compound are preferable from the viewpoint of reactivity. Most preferred are acrylates, methacrylates and urethane acrylates. Acrylate and methacrylate have a relatively large curing shrinkage, but in the present invention, since the film thickness can be reduced, there is no risk of appearance defects such as curling, and they can be suitably used. From the viewpoint of curl, urethane acrylate is most suitable because it has a small curing shrinkage.

The radical curable substance to be used may be a monomer, an oligomer or a polymer, but it is preferable to use a monomer or an oligomer from the viewpoint of solubility in an organic solvent and handleability. These may be used alone or in combination of two or more.

When a monomer is used as the (meth) acrylate, for example, trimethylolpropantri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol. Examples thereof include tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ethoxylated isocyanuric acid tri (meth) acrylate, and caprolactone-modified dipentaerythritol hexa (meth) acrylate.

When an oligomer is used as the (meth) acrylate, examples thereof include a polyfunctional (meth) acrylate oligomer, a polyester acrylate-based oligomer, an epoxy acrylate-based oligomer, a polyether acrylate-based oligomer, a polybutadiene acrylate-based oligomer, and a silicone acrylate-based oligomer. ..

The urethane acrylate used in the present invention means a urethane acrylate having a urethane bond and one or more radical curable functional groups selected from an acryloyl group and a methacryloyl group in the molecular chain. The synthesis method is not particularly limited, but it can be obtained, for example, by reacting a polyhydric alcohol or an organic polyisocyanate with a hydroxy acrylate.

Examples of the polyhydric alcohol include neopentyl glycol, 3-methyl-1,5-pentanediol, ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, trimethylolpropane, and pentaerythritol. , Tricyclodecanedimethylol, bis- [hydroxymethyl] -cyclohexane, etc .; Polyolpolyol obtained by reaction with (phthalic acid, etc.); Polycaprolactone polyol obtained by reaction of the above polyhydric alcohol with ε-caprolactone; Obtained by reaction of polycarbonate polyol (for example, 1,6-hexanediol and diphenylcarbonate). Polyether polyols and the like); and polyether polyols. Examples of the polyether polyol include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, ethylene oxide-modified bisphenol A and the like.

Examples of the organic polyisocyanate include isocyanate compounds such as isophorone diisocyanate, hexamethylene diisocyanate, tolylene diisocyanate, xylene diisocyanate, diphenylmethane-4,4'-diisocyanate, and dicyclopentanyl isocyanate, adducts of these isocyanate compounds, or these. Examples thereof include a multimer of isocyanate.

Examples of the hydroxy (meth) acrylate compound include pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and hydroxyethyl (meth). ) Acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, dimethylolcyclohexylmono (meth) acrylate, hydroxycaprolactone (meth) acrylate and the like can be mentioned. Of these, pentaerythritol tri (meth) acrylate and dipentaerythritol penta (meth) acrylate are preferable from the viewpoint of hardness.

As the urethane acrylate used in the present invention, commercially available ones can also be used. Examples of commercially available products are: UV1700B (10 functional), UV7620EA (9 functional), UV7610B (9 functional), UV7600B (6 functional), UV7650B (5 functional), manufactured by Nippon Kayaku Co., Ltd .: DPHA40H (10 functionals), UX5003 (6 functionals), Arakawa Chemical Industry Co., Ltd .: Beam set 577 (6 functionals), Taisei Fine Chemicals Co., Ltd .: 8UX-015A (15 functionals), and Shin Nakamura Chemical Industry Co., Ltd .: U15HA (15) Sensory) and the like.

The compound having an alkenyl group used for the release layer of the present invention is not particularly limited, and a general compound can be preferably used. Examples of commercially available products are: TAIC (registered trademark) triallyl isocyanurate (trifunctional) manufactured by Nihon Kasei Corporation, LDAIC (bifunctional), TA-G (4 functional), DD-1 manufactured by Shikoku Kasei Corporation. (4 sensuality) and the like.

(Thiolu group-containing compound (b))
The release layer in the present invention preferably contains a thiol group-containing compound. Since the thiol group-containing compound acts as a curing accelerator for the radical polymerization reaction, it is not easily affected by oxygen inhibition and exhibits excellent reactivity even in the air. Therefore, it is preferable because the curability of the release layer surface can be enhanced and the solvent resistance can be improved. Further, since oxygen inhibition is suppressed, even if the release layer is made into a thin film, the solvent resistance does not deteriorate and peeling failure does not occur, which is preferable. Further, since the thiol group-containing compound proceeds with the radical curable functional group and the addition polymerization reaction, it is incorporated into the crosslinked structure of the radical curable substance, and the flexible structure derived from the thiol group-containing compound is introduced into the cured product. Therefore, even if the release layer is thick, curing shrinkage, which is a problem peculiar to radical curable substances, is suppressed, uneven thickness of the ceramic green sheet occurs during molding of the ceramic green sheet, and electrode printing accuracy is lowered. It is preferable because there is no risk of causing.

When a coating film containing a radical curable substance is cured in the air, polar groups such as hydroxyl groups and carboxyl groups are formed on the surface due to oxygen inhibition, so that the wettability of the ceramic slurry is improved. When a coating film containing a radical curable substance is cured under an inert gas atmosphere, the effect of suppressing oxygen inhibition is large and the surface curability can be improved, but on the other hand, the wettability of the ceramic slurry is poor. Therefore, there is a problem that repellents and pinholes are likely to occur on the molded ceramic green sheet. The thiol group-containing compound is preferable because it can exhibit both the two contradictory effects of improving the surface hardness and improving the wettability by oxygen inhibition.

Further, by forming a release layer made of a cured product containing a thiol group-containing compound, S atoms are introduced into the release layer, so that the affinity with the molded ceramic green sheet is improved. For this reason, the ceramic green sheet is difficult to float during transportation, and the occurrence of defects can be suppressed, which is preferable.

The thiol group-containing compound is not particularly limited and a general compound is used, but it is preferable that the thiol group-containing compound does not contain a radical curable functional group selected from a (meth) acryloyl group and an alkenyl group. By using the thiol group-containing compound having no radical curable functional group, the radical curable functional groups in the same molecule react preferentially with each other over the thiol group acting as a curing accelerator, and oxygen It is preferable because there is no risk that the effect of suppressing inhibition cannot be obtained. The thiol group-containing compound in the present invention refers to an organic compound having a hydrogenated sulfur atom at the end, and is synonymous with a compound called thioalcohol. The thiol group may also be called a mercapto group or a sulfhydryl group.

The number of functional groups of the thiol group-containing compound is preferably 2 or more, more preferably 3 or more, and most preferably 4 or more. When the number of functional groups is two or more, it becomes easy to form a crosslinked structure with a radical curable substance, and it becomes easy to obtain the effect of suppressing oxygen inhibition, which is preferable.

Examples of the thiol group-containing compound include 1,4-bis (3-mercaptobutylyloxy) butane and tetraethylene glycol bis (3-mercaptopropionate) 1,3,5-tris (3-mercaptobutyryloxy). Ethyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H)-Trione, Trimethylol Propanthris (3-Mercaptopropionate), Tris-[(3-Mercaptopropionyloxy)- Ethyl] -isocyanurate, pentaerythritol tetrakis (3-mercaptopropionate), pentaerythritol tetrakis (3-mercaptobutyrate), dipentaerythritol hexakis (3-mercaptopropionate) and the like.

As the thiol group-containing compound, commercially available compounds can be preferably used. For example, Showa Denko: Karenz MT (registered trademark) BD1 (bifunctional), NR1 (3 functional), PE1 (4 functional), SC Organic Chemistry: TMMP (3 functional), TEMPIC (3 functional) , PEMP (4 functional), EGMP-4 (4 functional) DPMP (6 functional) and the like.

As the thiol group-containing compound, a polymer, an oligomer, or a monomer can be preferably used, but a monomer is most preferable. The molecular weight is preferably 10,000 or less, and most preferably 1000 or less. By setting the molecular weight to 10,000 or less, the number of thiol groups per constant mass becomes a sufficient number to obtain the effect of promoting radical curing, which is preferable.

The content of the thiol group-containing compound contained in the release layer is preferably 1 to 30% by mass or less, and more preferably 2 to 25% by mass or less, based on the solid content of the entire release layer. It is preferably 5 to 20% by mass or less, and most preferably 5 to 20% by mass or less. It is preferable that the content of the thiol group-containing compound is 1% by mass or more because the effect of promoting the radical curing reaction and making it less susceptible to oxygen inhibition can be sufficiently obtained. When the content is 30% by mass or less, the cured product does not become too flexible due to the thiol group-containing compound, and the effect of improving the elastic modulus by cross-linking between the radical curable substances can be obtained, which is preferable.

(Release agent (c))
Examples of the release agent (additive for imparting releasability) used for the release layer in the present invention include silicone-based additives and non-silicone-based additives such as fluorine-based, long-chain alkyl-based, and olefin-based additives. Can be suitably used respectively.

The silicone-based additive is a material having a polyorganosiloxane having an organic group attached to the siloxane bond, and is not particularly limited as long as the effect of the present invention can be obtained, and a general one should be used. Can be done. Among the polyorganosiloxanes, dialkylsiloxane can be preferably used, and among them, dimethylsiloxane is more preferable, and those having a functional group as a part of dimethylsiloxane are further preferable. Having a functional group is preferable because it facilitates the development of intermolecular interactions such as hydrogen bonds with radical curable substances and makes it difficult for migration to a ceramic green sheet to occur.

The functional group to be introduced into the polydimethylsiloxane is not particularly limited, and may be a reactive functional group or a non-reactive functional group. Further, the functional group may be introduced into one end of the polydimethylsiloxane, or may be both ends or a side chain. Further, the number of positions to be introduced may be one or a plurality.

As the reactive functional group to be introduced into the polydimethylsiloxane, a hydroxy group, a carboxyl group, a (meth) acryloyl group, an alkenyl group, a thiol group and the like can be used. Above all, it is preferable to have a radically curable functional group such as a (meth) acryloyl group, an alkenyl group and a thiol group. By using polydimethylsiloxane having a radical curable functional group, it is possible to form a crosslinked structure with the radical curable substance (a) and the thiol group-containing compound (b), and the transfer to the ceramic green sheet is difficult to occur. preferable. From the viewpoint of solvent resistance, the larger the number of reactive functional groups, the easier it is to form a crosslinked structure, which is preferable. The radical curable functional group shown here refers to a functional group that can be a cross-linking point in a radical curing reaction, such as a (meth) acryloyl group or an alkenyl group.

As the non-reactive functional group to be introduced into the polydimethylsiloxane, a polyether group, an alkyl group, a fluoroalkyl group, a long chain alkyl group, an ester group, an amide group, a phenyl group and the like can be used.

As the silicone component, it is particularly preferable to use a polydimethylsiloxane-modified resin such as an acrylic resin, a polyester resin, or a urethane resin having polydimethylsiloxane in the side chain. The polydimethylsiloxane modified resin is preferable because it has better compatibility with radical curable substances and can form a uniform release layer as compared with other general release agents, and thus has improved releasability. Further, it is preferable because the interaction between the radical curable substance and the molecule is likely to occur and the solvent resistance is improved. Further, it is preferable because the transfer of the release agent to the ceramic green sheet is less likely to occur at the time of peeling. Among the polydimethylsiloxane modified resins, it is preferable to use a polydimethylsiloxane modified resin having a radical curable functional group. A polydimethylsiloxane modified resin having a radical curable functional group is preferable because it can have a crosslinked structure with the radical curable substance (a) and the thiol group-containing compound (b), and thus the solvent resistance is further improved.

Examples of commercially available acrylic resins having a polydimethylsiloxane skeleton in the side chain include Cymac (registered trademark) US350, Cymac (registered trademark) US352, (Toagosei), 8BS-9000 (Taisei Fine Chemical), and others. Examples thereof include GL-01 and GL-03R (manufactured by Kyoeisha Chemical Co., Ltd.). Examples of commercially available acrylic resins having a polydimethylsiloxane skeleton and radical curable functional groups in the side chains include 8SS-723, (manufactured by Taisei Fine Chemical Co., Ltd.), GL-02, GL-04R (manufactured by Kyoei Co., Ltd.), etc. Can be mentioned.

The fluorine-based additive is not particularly limited, and existing ones can be used. For example, those having a perfluoro group and those having a perfluoroether group can be preferably used. For the same reason as the silicone-based additive, it is preferable to have a functional group, and it is further preferable to have a radical curable functional group. Commercially available products include 8FX-038EX (manufactured by Taisei Fine Chemicals), Optool (registered trademark) (manufactured by Daikin Industries, Ltd.), Megafuck (registered trademark) RS-72-K, RS-75, RS-78 (above, DIC). , F Escort (registered trademark) UT-UCH23 (made by AGC Seimi Chemical Co., Ltd.), EBECRYL (registered trademark) 8110 (manufactured by Daisel Ornex), F-Clear (registered trademark) (manufactured by Kanto Denka Kogyo Co., Ltd.), etc. Will be.

As the long-chain alkyl-based additive, a resin modified with a long-chain alkyl can be used, and those having an alkyl group having about 8 to 20 carbon atoms in the side chain such as polyvinyl alcohol or acrylic resin are preferable. Further, a polymer having a (meth) acrylic acid ester as a main repeating unit and having a transesterified portion containing a long-chain alkyl group having 8 to 20 carbon atoms can also be preferably used. Further, octyl acrylate, lauryl acrylate, stearyl acrylate and the like having an acrylate group attached to a long-chain alkyl can also be preferably used.

Examples of commercially available long-chain alkyl additives include Pyroyl (registered trademark) 1010, 1050, 1070 (above, manufactured by Lion Specialty Chemicals), Tessfine (registered trademark) 305, 314 (above, Hitachi). (Made by Kaseisha), etc.

The olefin-based additive is not particularly limited, and general ones can be used. For example, polybutadiene, cycloolefin-based resin, and the like can be preferably used. Examples of commercially available products include NISSO-PB (registered trademark) B series, G series, JP series (hereinafter, manufactured by Nippon Soda Co., Ltd.), ARTON (registered trademark) (manufactured by JSR Corporation), and the like.

Further, two or more kinds of the above mold release agents may be mixed and used. At this time, although not particularly limited by theory, it is more preferable to use two types having different functional groups in terms of peelability, and it is more preferable to use a reactive functional group.

The release layer in the present invention preferably contains the release agent (c) in an amount of 0.05% by mass or more and 20% by mass or less based on the solid content of the entire 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 the amount is more than 0.1% by mass, releasability is imparted, and there is no possibility that the peelability of the ceramic green sheet is deteriorated, which is preferable. By making it less than 20% by mass, it becomes difficult for repelling to occur when the ceramic slurry is applied, and there is no possibility that the thickness of the ceramic green sheet becomes uneven.

(Radical initiator (d))
It is preferable to use a radical initiator for the release layer in the present invention in order to promote the radical curing reaction. As the radical initiator, both a thermal radical initiator and a photoradical initiator can be preferably used, but it is preferable to use a photoradical initiator because the amount of heat during processing can be suppressed. The initiator to be used may be one type or two or more types, and a photoradical initiator and a thermal radical initiator may be used at the same time.

The radical initiator is not particularly limited and a general one can be used. Specific examples 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-Hydroxycyclohexylphenyl ketone, benzyldiphenylsulfide, tetramethylthium monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, β-chloranthraquinone, (2,4,6-trimethylbenzyldiphenyl) phosphine Examples thereof include oxide, 2-benzothiazole-N, N-diethyldithiocarbamate and the like.

As the radical initiator, α-hydroxyalkylphenone and α-aminoalkylphenone, which are said to be particularly excellent in surface curability, can be suitably used for suppressing oxygen inhibition. Examples of α-hydroxyalkylphenone are 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] -phenyl}-. 2-Methylpropane-1-one, 2-hydroxy-2-methyl-1-phenyl-propane-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl- 1-Propane-1-one and the like can be mentioned. Examples of α-aminoalkylphenone are 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopro. Examples thereof include pan-1-one, 2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholyl) phenyl] -1-butanone and the like.

When a photoradical initiator is used, the addition of a sensitizer can promote the absorption of active energy rays and further improve the curability. The sensitizer is not particularly limited and a general one is used, but an anthracene derivative and a naphthalene derivative are preferable. One kind or two or more kinds of sensitizers may be used.

The amount of the radical initiator added is preferably 0.1% by mass or more and 20% by mass or less, preferably 0.5% by mass or more and 10% by mass or less, based on the total solid content in the release layer. It is more preferable, and it is most preferable that it is 1% by mass or more and 8% by mass or less. When it is 0.1% by mass or more, the amount of radicals generated is insufficient and there is no possibility of insufficient curing, which is preferable. When the content is 20 parts by mass or less, the amount of the radical initiator residue contained in the release layer is reduced, and it is possible to suppress deterioration of peelability and transfer to the ceramic green sheet to be molded, which is preferable.

The amount of the sensitizer added is preferably 0.1 to 5 times the mass of the photoradical initiator. More preferably, it is 0.1 to 2 times. When it is larger than 0.1 times, a sufficient sensitizing effect can be obtained, which is preferable. When it is smaller than 5 times, it is preferable because there is no possibility that the absorption of active energy rays of the photoradical initiator is hindered and the amount of generated radicals is insufficient.

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.

In the present invention, the thickness of the release layer may be set according to the purpose of use and is not particularly limited, but preferably, the release coating layer after curing is preferably in the range of 0.01 to 0.5 μm. , More preferably 0.05 to 0.4 μm, and more preferably 0.1 to 0.4 μm. In particular, when a release layer is provided on the surface layer A of a polyester film having a surface layer A that does not substantially contain inorganic particles, the thinner the release layer, the lower the coating material cost. This is preferable because it is economical and curl generation can be suppressed. Specifically, it is preferably 0.4 μm or less, and more preferably 0.3 μm or less. It is preferable that the thickness of the release layer is thicker than 0.01 μm because sufficient peeling performance can be obtained. Further, if it is thinner than 0.5 μm, curling of the release film due to curing shrinkage is unlikely to occur, so that there is no possibility of causing uneven thickness of the ceramic green sheet and deterioration of electrode printing accuracy, which is preferable.

The surface of the release layer 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, and the region surface average roughness (Sa) is 7 nm or less. It is preferable to have. Further, it is more preferable that the Sa is satisfied and the maximum protrusion height (P) on the surface of the release layer is 100 nm or less. It is particularly preferable that the region surface average roughness (Sa) 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, 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.

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, it is 0.8 mN / mm or more and 3.0 mN / mm or less. When the peeling force is 0.5 mN / mm or more, the peeling force is too light and there is no possibility that the ceramic green sheet will float during transportation, which is preferable. When the peeling force is 4.0 mN / mm or less, the ceramic green sheet is not damaged at the time of peeling and there is no possibility of causing defects, which is preferable.

The release film of the present invention is preferable because the higher the solvent resistance, the more the erosion of the release layer by an organic solvent such as toluene during ceramic sheet processing and electrode printing can be suppressed. 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, which is used for a general ceramic slurry or a conductive paste, assuming ceramic green sheet processing or electrode printing. An example of a method for evaluating the surface state of the release layer is evaluation based on the contact angle, and it is preferable that the change in the contact angle on the surface of the release layer before and after immersion in toluene is small.

The type of liquid plucking used to measure the contact angle is not particularly limited, but water, bromonaphthalene, ethylene glycol and the like can be preferably used, but the difference in the surface state of the release layer can be seen more prominently. It is most preferable to use diiodomethane which can be used.

When diiodomethane was used as the liquid picker used to measure the contact angle, the diiodomethane contact angle θ ₁ on the surface of the release layer and the contact angle θ on the surface of the release layer after immersing the release film in toluene at room temperature for 5 minutes. The smaller the value of the difference between ₂ (θ ₁ − θ ₂ ), the better the solvent resistance of the release layer surface, 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. When the temperature is 3.0 ° or less, erosion of the release layer by the organic solvent during ceramic green sheet processing or electrode printing is suppressed, and there is no possibility that the peeling force is increased or the peeling uniformity is impaired, which is preferable. The difference (θ ₁ − θ ₂ ) between the diiodomethane contact angle θ ₁ on the surface of the release layer and the contact angle θ ₂ on the surface of the release layer after immersing the release film in toluene at room temperature for 5 minutes is most preferable. The absolute value may be 0.05 ° or more, or 0.1 ° or more.

The release film of the present invention is preferably less curled. When the curl is small, the uniformity at the time of coating and molding the ceramic green sheet deteriorates, and there is no possibility that the film thickness of the ceramic green sheet becomes non-uniform, which is preferable. Further, it is preferable because there is no possibility that the printing accuracy is lowered in the electrode printing process. Further, it is preferable that the tension of the release film is less likely to be different between the central portion and the end portion of the release film during roll transfer, and the appearance quality such as meandering and winding misalignment during transfer is not deteriorated.

(Method of forming the release layer)

In the present invention, the method for forming the release layer is not particularly limited, and a coating liquid in which a composition containing a releaseable resin or the like is dissolved or dispersed is applied to one surface of a polyester film of a base material to develop it. Then, a method is used in which the solvent and the like are removed by drying, heat-dried, and then cured by irradiation with active energy rays or heat.

When curing using a photoradical initiator, the drying temperature for solvent drying is preferably 50 ° C. or higher and 100 ° C. or lower, and more preferably 60 ° C. or higher and 95 ° C. or lower. The heating time is preferably 30 seconds or less, more preferably 20 seconds or less. When the temperature is 100 ° C. or lower, the thermal load on the film is suppressed, appearance defects due to heat shrinkage of the film are less likely to occur, and there is less risk of causing uneven thickness of the ceramic green sheet, which is preferable. When the temperature is 95 ° C. or lower, the thermal load on the film is further reduced, processing can be performed without impairing the flatness of the film, and the possibility of causing uneven thickness of the ceramic green sheet is further reduced, which is particularly preferable. If the temperature is higher than 50 ° C., the diluting solvent used for coating will not be sufficiently dried, and there is no possibility of process contamination and the like, which is preferable.

As the active energy ray used for reacting the radical curable substance with the photoradical initiator, ultraviolet rays, electron beams, X-rays and the like can be used, but ultraviolet rays are preferable because they are easy to use. The amount of ultraviolet rays to be irradiated is preferably 30 to 300 mJ / cm ² in terms of integrated light amount, and more preferably 30 to 200 mJ / cm ² . A setting of 30 mJ / cm ² or more is preferable because the curing of the resin proceeds sufficiently. It is preferable that the speed is 300 mJ / cm ² or less because the speed at the time of processing can be improved and the release film can be economically produced.

The atmosphere when irradiating the active energy rays may be an atmosphere of an inert gas such as nitrogen or argon, but it is preferably in general air. In the present invention, by using the thiol group-containing compound, it is possible to obtain a release layer having excellent curability on the surface of the release layer even when irradiated in air and excellent wettability of the ceramic slurry. In addition, it is superior in terms of processing cost to that performed in an inert gas atmosphere, and is preferable from an 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 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 prime field. Inside the ceramic prime field, 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 prime field. 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 prime field. 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 prime field 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 prime field. A ceramic prime is obtained by firing a raw ceramic prime. 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.

(Intrinsic viscosity of polyester resin (dl / g))
According to JIS K 7637-5, a mixed solvent of phenol (60% by mass) and 1,1,2,2-tetrachloroethane (40% by mass) was used as a solvent, and the measurement was carried out at 30 ° C.

(Base film thickness)
Using a millitron (electronic micro-indicator), four 5 cm square samples were cut from any four points of the film to be measured, and each five points (20 points in total) were measured and the average value was taken as the thickness.

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

(Region surface roughness Sa, maximum protrusion 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.). 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

(Pinhole evaluation 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 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 (registered trademark) BM-S manufactured by Sekisui Chemical Co., Ltd.) 3.5 parts by mass DOP (dioctyl phthalate) 1.8 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 90 ° C for 2 minutes. After that, the release film was peeled off to obtain a ceramic green sheet. In the central region of the obtained ceramic green sheet in the film width direction, shine light from the opposite surface of the coated surface of the ceramic slurry within a range of 25 cm ² , observe the occurrence of pinholes through which light can be seen, and use the following criteria. It was judged visually. The measurement was carried out 5 times, and the average value was adopted.
⊚: No pinholes ○: Almost no pinholes (approximate: 2 or less pinholes per measured area)
Δ: Pinholes may occur (approximate: 3 or more and 5 or less pinholes per measurement area)
×: There are many pinholes

(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 (Sekisui Chemical Co., Ltd. Eslek BM-S) 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 becomes 0.8 μm, dry at 90 ° C for 2 minutes, and then use the following criteria. The coatability was evaluated in.
○: 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.
×: Repellent is generated at areas other than the coated end, and the entire surface cannot be coated.

(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 6.5 parts by mass (Sekisui Chemical Co., Ltd. Eslek (registered trademark) BM-S )
DOP (Dioctyl phthalate) 3.3 parts by mass Next, apply the dried ceramic green sheet to the release surface of the release film sample to a thickness of 10 μm using an applicator, and dry at 90 ° C for 2 minutes to make the ceramic green. 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 to prepare a sample for measuring the peeling force. After static elimination using an electric eliminator (Keyence, SJ-F020), a peeling tester (VPA-3, Kyowa Interface Science) is used to peel off at an angle of 90 degrees, a peeling temperature of 25 ° C, and a peeling speed of 10 m /. It peeled off at min. As for the direction of peeling, a double-sided adhesive tape (Nitto Denko Co., Ltd., No. 535A) is attached on the SUS plate attached to the peeling tester, and the ceramic green sheet side is bonded to the double-sided tape on the release film. Was fixed and peeled off by pulling on the release film side. 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.
⊚: The peeling force was 2.0 mN / mm or less, and the peeling force was very light.
◯: The peeling force was larger than 2.0 mN / mm, and peeling was possible with a relatively light force of 3.0 mN / mm or less.
Δ: The peeling force was larger than 3.0 mN / mm, and peeling was possible with a light force of 4.0 mN / mm or less.
X: A force having a peeling force greater than 4.0 mN / mm was required.

(Curl evaluation of release film)
The release film sample was cut into a size of 10 cm × 10 cm, and heat-treated at 90 ° C. for 1 minute 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 height of the portion floating from the glass plate was measured. At this time, the height of the portion most floating from the glass plate was taken as the measured value. The curl property was evaluated according to the following criteria.
⊚: The curl was 1 mm or less and hardly curled. ◯: The curl was larger than 1 mm and 2 mm or less, and a little curl was observed.
Δ: The curl was larger than 2 mm and 4 mm or less, and curl was observed.
X: The curl was larger than 4 mm.

(Contact angle)
Diiodomethane (droplet amount) was used on the release surface of the release film that had been allowed to stand using a contact angle meter (fully automatic contact angle meter DM-701 manufactured by Kyowa Interface Science Co., Ltd.) under the conditions of 25 ° C and 50% RH. A droplet of 0.9 μL) was prepared and the contact angle thereof was measured. As the contact angle, the contact angle 30 seconds after dropping on the release film was adopted, and the average value of the values measured 5 times was adopted.

(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 at a liquid temperature of 25 ° C. for 5 minutes with the release side facing down. The soaked release film was taken out, air-dried for 15 minutes with the release side facing up, and then vacuum-dried at 25 ° C. overnight. The release film after immersion in toluene thus obtained was measured by the same method as the method for measuring the contact angle.

(Evaluation of contact angle change)
When the diiodomethane contact angle of the initial release layer surface before toluene immersion 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 in contact angle was evaluated based on 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 °

(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 made up to 160 ppm of Sb atoms with respect to the PET produced, and these slurrys are esterified. It was continuously supplied to the first esterification reaction can of the chemical reaction apparatus, and reacted at normal pressure with an average residence time of 4 hours and 255 ° C. Next, the reaction product in the first esterification reaction can is continuously taken out of the system and supplied to the second esterification reaction can, and distilled off from the first esterification reaction can in the second esterification reaction can. EG is supplied in an amount of 8% by mass with respect to the produced PET, and further, an EG solution containing an amount of magnesium acetate tetrahydrate in an amount of 65 ppm with respect to the produced PET and 40 ppm of P atom 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 chip, a PET chip having an intrinsic viscosity of 0.62 dl / g containing no inorganic particles such as calcium carbonate and silica was obtained (hereinafter abbreviated as PET (II)).

(Manufacturing of laminated film X1)
These PET chips are dried, melted at 285 ° C, melted at 290 ° C by a separate melt extruder extruder, and have a filter obtained by sintering stainless steel fibers having a 95% cut diameter of 15 μm, and 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) / PET (II) = 60% / 40% in the discharge amount calculation of each extruder. Next, the unstretched sheet was heated with an infrared heater and then stretched 3.5 times in the vertical direction at a roll temperature of 80 ° C. due to the speed difference between the rolls. Then, it was guided to a tenter and stretched 4.2 times in the lateral direction at 140 ° C. Then, in the heat fixing zone, heat treatment was performed at 210 ° C. Then, a 2.3% relaxation treatment was carried out laterally at 170 ° C. to obtain a biaxially stretched polyethylene terephthalate film X1 having a thickness of 25 μm. The Sa of the surface layer A of the obtained film X1 was 2 nm, and the Sa of the surface layer B was 29 nm.

(Manufacturing of laminated film X2)
The thickness was adjusted by changing the speed at the time of casting without changing the layer structure and stretching conditions similar to those of the laminated film X1 to obtain a biaxially stretched polyethylene terephthalate film X2 having a thickness of 22 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.

(Manufacturing method of laminated film X3)
As the laminated film X3, E5101 (Toyobo Ester (registered trademark) film, manufactured by Toyobo Co., Ltd.) having a thickness of 25 μm was used. E5101 has a structure in which inorganic particles are contained in the film. The Sa of the surface layer A of the laminated film X3 was 24 nm, and the Sa of the surface layer B was 24 nm.

(Example 1)
A coating liquid 1 having the composition shown below is applied onto the surface layer A of the laminated film X1 using a wire bar so that the release layer thickness after drying is 0.4 μm, and dried at 90 ° C. for 15 seconds. Then, a release film for producing an ultrathin ceramic green sheet was obtained by irradiating ultraviolet rays (manufactured by Heraeus, LC6B, H bulb) having an integrated light amount of 70 mJ / cm ² in the atmosphere. A ceramic slurry was applied to the obtained release film, and the surface roughness, peelability, pinhole, coatability, curl, and solvent resistance of the release layer were evaluated. As a result, good evaluation results were obtained.
Methyl ethyl ketone 22.40 parts by mass Isopropyl alcohol 67.20 parts by mass Radical curable substance (a): 10-functional urethane acrylate 8.50 parts by mass (Product name: Shikou (registered trademark) UV-1700B, manufactured by Nippon Synthetic Chemical Co., Ltd., solid Minute 100% by mass)
Thiol group-containing compound (b): 1.00 part by mass of tetrafunctional thiol group-containing compound
(Product name: Calends MT (registered trademark) PE1, manufactured by Showa Denko KK, solid content 100% by mass)
Release agent (c): Acryloyl group-containing acrylic silicone 0.50 parts by mass (Product name: GL-04R, manufactured by Kyoeisha Chemical Co., Ltd., solid content 20% by mass)
Radical Initiator (d): 2-Hirodoxy-1- {4- [4- (2-Hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one 0.40 parts by mass (Product name: Omnirad127, manufactured by IGM Resins, solid content 100% by mass)

(Example 2)
Release for manufacturing ultra-thin ceramic green sheet in the same manner as in Example 1 except that the radical curable substance (a) was changed to 9-functional urethane acrylate (Shikou (registered trademark) UV-7620EA, manufactured by Nippon Synthetic Chemistry Co., Ltd.). Obtained a mold film.

(Example 3)
Release for manufacturing ultra-thin ceramic green sheet in the same manner as in Example 1 except that the radical curable substance (a) was changed to a hexafunctional urethane acrylate (Shikou (registered trademark) UV-7600B, manufactured by Nippon Synthetic Chemistry Co., Ltd.). Obtained a mold film.

(Example 4)
Release for manufacturing ultra-thin ceramic green sheet in the same manner as in Example 1 except that the radical curable substance (a) was changed to a pentafunctional urethane acrylate (Shikou (registered trademark) UV-7650B, manufactured by Nippon Synthetic Chemistry Co., Ltd.). Obtained a mold film.

(Example 5)
Release for manufacturing ultra-thin ceramic green sheet in the same manner as in Example 1 except that the radical curable substance (a) was changed to a trifunctional urethane acrylate (Shikou (registered trademark) UV-7550B, manufactured by Nippon Synthetic Chemistry Co., Ltd.). Obtained a mold film.

(Example 6)
A release film for producing an ultrathin ceramic green sheet was obtained in the same manner as in Example 1 except that the radical curable substance (a) was changed to a hexafunctional acrylate (A-DPH, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.). ..

(Example 7)
A release film for producing an ultrathin ceramic green sheet was obtained in the same manner as in Example 1 except that the radical curable substance (a) was changed to a tetrafunctional acrylate (A-TMMT, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.). ..

(Example 8)
A release film for producing an ultrathin ceramic green sheet was prepared in the same manner as in Example 1 except that the radical curable substance (a) was changed to a dendrimer type polyfunctional acrylate (SIRIUS-501, manufactured by Osaka Organic Chemical Industry Co., Ltd.). Obtained.

(Example 9)
Mold release for manufacturing ultra-thin ceramic green sheet in the same manner as in Example 1 except that the radical curable substance (a) was changed to a trifunctional allyl compound (Tyke (registered trademark) triisocyanurate, manufactured by Nihon Kasei Co., Ltd.). I got a film.

(Examples 10 and 11)
A release film for producing an ultrathin layer ceramic green sheet was obtained in the same manner as in Example 1 except that the content of the thiol group-containing compound (b) was changed to the amount shown in Table 1.

(Example 12)
A release film for producing an ultrathin ceramic green sheet was prepared in the same manner as in Example 1 except that the thiol group-containing compound (b) was changed to a trifunctional thiol (Calends MT (registered trademark) NR1, manufactured by Showa Denko KK). Obtained.

(Example 13)
A release film for producing an ultrathin ceramic green sheet was prepared in the same manner as in Example 1 except that the thiol group-containing compound (b) was changed to a bifunctional thiol (Calends MT (registered trademark) BD1, manufactured by Showa Denko KK). Obtained.

(Example 14)
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 22.50 parts by mass isopropyl alcohol 67.50 parts by mass Radical curable substance (a): Hexofunctional acrylate 8.50 parts by mass (Product name: A-DPH, manufactured by Shin Nakamura Chemical Industry Co., Ltd., solid content 100% by mass)
Thiol group-containing compound (b): 1.00 part by mass of tetrafunctional thiol group-containing compound
(Product name: Calends MT (registered trademark) PE1, manufactured by Showa Denko KK, solid content 100% by mass)
Release agent (c):
0.10 parts by mass of acryloyl group-containing polyether-modified polydimethylsiloxane (product name: BYK UV-3500, manufactured by Big Chemie Japan, solid content 100% by mass)
Radical Initiator (d): 2-Hirodoxy-1- {4- [4- (2-Hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one 0.40 parts by mass (Product name: Omnirad127, manufactured by IGM Resins, solid content 100% by mass)

(Example 15)
Manufacture of ultra-thin ceramic green sheet in the same manner as in Example 1 except that the mold release agent (c) was changed to a fluorine-based mold release agent (product name: Megafuck (registered trademark) RS-75, manufactured by DIC Corporation). A release film was obtained.

(Example 16)
A mold release film for producing an ultrathin ceramic green sheet was obtained in the same manner as in Example 1 except that the mold release agent (c) was changed to stearyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd.).

(Example 17)
Production of ultra-thin ceramic green sheet in the same manner as in Example 1 except that the release agent (c) was changed to acryloyl group-containing polyether-modified polydimethylsiloxane (product name: BYK-UV3500, manufactured by Big Chemie Japan). A release film was obtained.

(Example 18)
A mold release film for manufacturing an ultrathin ceramic green sheet was obtained in the same manner as in Example 1 except that the release layer was coated so that the film thickness was 1.0 μm.

(Example 19)
A mold release film for producing an ultrathin ceramic green sheet was obtained in the same manner as in Example 1 except that the release layer was coated so that the film thickness was 0.2 μm.

(Example 20)
A mold release film for producing an ultrathin ceramic green sheet was obtained in the same manner as in Example 1 except that the release layer was coated so that the film thickness was 0.05 μm.

(Example 21)
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 X2.

(Example 22)
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 X3.

(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 coating liquid had the composition shown below.
Methyl ethyl ketone 22.40 parts by mass isopropyl alcohol 67.20 parts by mass Radical curable substance (a): 10-functional urethane acrylate 9.50 parts by mass (Product name: Shikou (registered trademark) UV-1700B, manufactured by Nippon Synthetic Chemical Co., Ltd., solid Minutes 100%)
Release agent (c): Acryloyl group-containing acrylic silicone 0.50 parts by mass (Product name: GL-04R, manufactured by Kyoeisha Chemical Co., Ltd., solid content 20% by mass)
Radical Initiator (d): 2-Hirodoxy-1- {4- [4- (2-Hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one 0.40 parts by mass (Product name: Omnirad127, manufactured by IGM Resins, solid content 100% by mass)

(Comparative Example 2)
A release film for producing an ultrathin ceramic green sheet was obtained by the same method as in Example 1 except that the coating liquid had the composition shown below.
Methyl ethyl ketone 22.50 parts by mass Isopropyl alcohol 67.50 parts by mass Radical curable substance (a) 10-functional urethane acrylate 8.60 parts by mass (Product name: Shikou (registered trademark) UV1700B, manufactured by Nippon Synthetic Chemical Co., Ltd., solid content 100% )
Thiol group-containing compound (b): 1.00 part by mass of tetrafunctional thiol group-containing compound
(Product name: Calends MT (registered trademark) PE1, manufactured by Showa Denko KK, solid content 100% by mass)
Radical Initiator (d): 2-Hirodoxy-1- {4- [4- (2-Hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one 0.40 parts by mass (Product name: Omnirad127, manufactured by IGM Resins, solid content 100% by mass)

(Comparative Example 3)
A mold release film for producing an ultrathin ceramic green sheet was obtained in the same manner as in Comparative Example 1 except that the release layer was coated so that the film thickness was 1.0 μm.

(Comparative Example 4)
A mold release film for producing an ultrathin ceramic green sheet was obtained by the same method as in Comparative Example 1 except that the release layer was coated so that the film thickness was 0.05 μm.

(Comparative Example 5)
A release film for producing an ultrathin ceramic green sheet was obtained by the same method as in Example 1 except that the coating liquid had the composition shown below.
Methyl ethyl ketone 22.50 parts by mass Isopropyl alcohol 67.50 parts by mass Radical curable substance (a) Hexofunctional acrylate 9.50 parts by mass (Product name: A-DPH, manufactured by Shin Nakamura Chemical Industry Co., Ltd., solid content 100% by mass)
Release agent (c):
0.10 parts by mass of acryloyl group-containing polyether-modified polydimethylsiloxane (product name: BYK UV-3500, manufactured by Big Chemie Japan, solid content 100% by mass)
Radical Initiator (d): 2-Hirodoxy-1- {4- [4- (2-Hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one 0.40 parts by mass (Product name: Omnirad127, manufactured by IGM Resins, solid content 100% by mass)

(Comparative Example 6)
A mold release film for producing an ultrathin ceramic green sheet was obtained in the same manner as in Comparative Example 5 except that the release layer was coated so that the film thickness was 1.0 μm.

(Comparative Example 7)
A release film for producing an ultrathin ceramic green sheet was obtained by the same method as in Example 1 except that a coating liquid having the following composition was used.
Methyl ethyl ketone 22.40 parts by mass Isopropyl alcohol 67.20 parts by mass Radical curable substance (a): Triallyl isocyanurate 9.50 parts by mass (Product name: Tyke (registered trademark), manufactured by Nihon Kasei Co., Ltd., 100% solid content)
Release agent (c): Acryloyl group-containing acrylic silicone 0.50 parts by mass (Product name: GL-04R, manufactured by Kyoeisha Chemical Co., Ltd., solid content 20% by mass)
Radical Initiator (d): 2-Hirodoxy-1- {4- [4- (2-Hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one 0.40 parts by mass (Product name: Omnirad127, manufactured by IGM Resins, solid content 100% by mass)

(Comparative Example 8)
A release film for producing an ultrathin ceramic green sheet was obtained in the same manner as in Comparative Example 1 except that it was cured by irradiating it with ultraviolet rays in a nitrogen atmosphere.

The release film for producing a ceramic green sheet of the present invention has a highly smooth release layer surface, a high crosslink density of the release layer, and excellent solvent resistance. Therefore, the release layer is not eroded during ceramic green sheet processing or electrode printing, and even when peeling an ultrathin ceramic green sheet with a thickness of 1 μm or less, the peeling force is low and uniform, resulting in defects such as pinholes. It is possible to mold a ceramic green sheet with less. Further, since the release film has less curl, it can be used without causing the thickness unevenness of the ceramic green sheet and the deterioration of the electrode printing accuracy.

Claims (12)

A mold release film having a mold release layer on at least one side of the polyester film.
The release layer is a radical curable substance (a) having one or more radical curable functional groups selected from a (meth) acryloyl group and an alkenyl group, a thiol group-containing compound (b), and a release agent (c). ), The composition containing the radical initiator (d) is cured.
Release film for manufacturing ceramic green sheets. The release film for producing a ceramic green sheet according to claim 1, wherein the thiol group-containing compound (b) does not have a radical curable functional group selected from a (meth) acryloyl group and an alkenyl group. The release film for producing a ceramic green sheet according to claim 1 or 2, wherein the thiol group-containing compound (b) is a compound having two or more thiol groups in one molecule. The difference (θ ₁ − θ ₂ ) between the diiodomethane contact angle θ ₁ on the surface of the release layer and the diiodomethane contact angle θ ₂ on the surface of the release layer after the release film is immersed in toluene is 3.0 ° or less as an absolute value. The release film for producing a ceramic green sheet according to any one of claims 1 to 3. The release agent (c) contains an acrylic resin having a polydimethylsiloxane skeleton in the side chain.
The release film for manufacturing a ceramic green sheet according to any one of claims 1 to 4. The release film for producing a ceramic green sheet according to any one of claims 1 to 4, wherein the release agent (c) is a compound containing a fluorine atom in the molecule. The release for ceramic green sheet production according to any one of claims 1 to 6, wherein the content of the thiol group-containing compound (b) is 1 to 30% by mass with respect to the total mass of the composition forming the release layer. Mold film. The polyester film has a surface layer A that does not substantially contain inorganic particles and a surface layer B on the opposite side that contains inorganic particles, and a release layer is provided on the surface layer A. The ceramic green sheet production according to any one of claims 1 to 7, wherein the inorganic particles contained in B are silica particles and / or calcium carbonate particles, and the total amount of the inorganic particles is contained in the surface layer B at 5000 to 15000 ppm. Release film. The release film for producing a ceramic green sheet according to any one of claims 1 to 8, wherein the release layer has a film thickness in the range of 0.01 μm or more and 0.5 μm or less. (Meta) Radical curable substance (a) having one or more radical curable functional groups selected from acryloyl group and alkenyl group, thiol group-containing compound (b), mold release agent (c), radical initiator ( The method for producing a release film for producing a ceramic green sheet according to any one of claims 1 to 9, wherein the composition containing d) is cured in the air to form a release layer. A method for producing a ceramic green sheet having a thickness of 0.2 μm to 1.0 μm, wherein the ceramic green sheet is produced by using the release film for producing the ceramic green sheet according to any one of claims 1 to 9. A method for manufacturing a ceramic capacitor, which employs the method for manufacturing a ceramic green sheet according to claim 11.