WO2023080026A1 - Release film for manufacturing ceramic green sheet - Google Patents

Abstract

Provided is a release film for manufacturing a ceramic green sheet, the release film exhibiting excellent releasability, wherein transfer and omission of a release layer and adherence defects do not easily occur.　The present invention pertains to a release film for manufacturing a ceramic green sheet, the release film comprising a polyester film and a release layer. The release layer is obtained by curing a curable composition comprising: a polysiloxane A having two or more intramolecular alkenyl groups; a polysiloxane B having two or more intramolecular hydrosilyl groups; and an adherence-imparting agent C, and is characterized in that the surface free energy γS (mJ/m²) at the surface of the release layer and a hydrogen bond component γSVh (mJ/m²) of γS satisfy expression (a) and expression (b).　(a): 1.0 ≤ γSVh/γS*100 ≤ 6.5; (b): γS ≤ 30

Description

Release film for manufacturing ceramic green sheets

The present invention relates to a release film for manufacturing ceramic green sheets, which has a polyester film and a release layer, and can be suitably used for manufacturing ultra-thin ceramic green sheets.

Conventionally, a release film made by laminating a release layer on a polyester film as a base material has been used as a film for various processes. Among others, release films for manufacturing ceramic green sheets are also used as process films for manufacturing ceramic green sheets that require high smoothness, such as laminated ceramic capacitors and ceramic substrates.

In recent years, along with the miniaturization and increase in capacity of multilayer ceramic capacitors, the thickness of ceramic green sheets tends to be thinner. A ceramic green sheet is molded by coating a release film with a slurry containing a ceramic component such as barium titanate and a binder resin and drying the slurry. A laminated ceramic capacitor is manufactured by laminating, pressing, firing, and applying external electrodes to the ceramic green sheets obtained by printing electrodes on molded ceramic green sheets and peeling them from the release film.

In recent years, ceramic green sheets have become thinner, and the releasability of the ceramic green sheets from the release film has become more important. If the peel force is large and non-uniform, the ceramic green sheet will be damaged in the peeling process, causing problems such as sheet defects, thickness unevenness, pinholes, sheet cracks, and the like. Therefore, it is required to peel off the ceramic green sheet with a lower and more uniform force.

As a measure to make the release layer easy to release, as in Patent Document 1, polydimethylsiloxane having an alkenyl group, polydimethylsiloxane having a hydrosilyl group, and a platinum catalyst are used, and are formed by an addition reaction such as heat. A release film having a silicone film as a release layer has been proposed.

In addition, as a measure to improve the curability of the release layer, Patent Document 2 discloses a radical-curable composition containing a polyorganosiloxane having a reactive functional group such as an acryloyl group and a polyfunctional (meth)acrylic acid ester. A release film having a release layer formed by curing a material has been proposed.

Japanese Patent No. 6619200 Japanese Patent No. 5492352

However, in the invention of Patent Document 1, there is a tendency that it is difficult to achieve both the adhesion of the release layer to the substrate film and the release property of the surface, and the silicone coating falls off from the release layer in the process of manufacturing the ceramic green sheet. However, there was concern that the process would be contaminated.

In addition, in the invention of Patent Document 2, if the curability is increased to the extent that transfer of the release layer can be prevented, there is a problem that sufficient releasability cannot be obtained when peeling the ceramic.

Accordingly, an object of the present invention is to provide a release film for producing a ceramic green sheet which is excellent in release properties and which is less susceptible to transfer/drop-off of the release layer and poor adhesion. Another object of the present invention is to provide a method for producing a ceramic green sheet using the release film.

As a result of intensive research to solve the above problems, the present inventors have found that, for a release layer cured by further adding an adhesion imparting agent, in particular, the ratio of the hydrogen bond component γSVh in the surface free energy γS is set within a predetermined range. The present inventors have found that the above problem can be solved by controlling to , and have completed the present invention.

That is, the present invention includes the following contents.

[1] A release film for producing a ceramic green sheet having a polyester film and a release layer,
The release layer comprises a polysiloxane A having two or more alkenyl groups in the molecule, a polysiloxane B having two or more hydrosilyl groups in the molecule, and an adhesion imparting agent C. A curable composition containing is a hardened layer of matter,
The surface free energy γS (mJ/m ² ) of the surface of the release layer and the hydrogen bond component γSVh (mJ/m ² ) of γS satisfy the following formulas (a) and (b). release film for manufacturing ceramic green sheets.
1.0≤γSVh/γS*100≤6.5 (a)
γS≦30 (b)

[2] The ceramic according to [1], wherein the adhesion imparting agent C is a silane coupling agent having one or more functional groups selected from the group consisting of vinyl groups, epoxy groups, acrylic groups, and methacrylic groups. Release film for green sheet production.

[3] The release film for producing a ceramic green sheet according to [1] or [2], wherein the polysiloxane A has a weight average molecular weight of 300,000 or more and 600,000 or less.

[4] The molar ratio between the amount of hydrosilyl groups possessed by the polysiloxane B and the amount of alkenyl groups possessed by the polysiloxane A in the curable composition satisfies the following formula (c), [1] to [ 3] The release film for producing a ceramic green sheet according to any one of the above.
1.0≤Si-H/Si-A≤3.8 (c)
(In the formula, Si—H represents the molar amount of hydrosilyl groups, and Si—A represents the molar amount of alkenyl groups.)

[5] The curable composition contains 1% by mass or more and 10% by mass or less of the adhesion imparting agent C with respect to the total amount of the polysiloxane A and the polysiloxane B, [1] to [ 4] The release film for producing a ceramic green sheet according to any one of the above.

[6] The polyester film has a surface layer A that does not substantially contain inorganic particles,
The release layer is laminated on the surface layer A with a thickness of 0.005 μm or more and 0.1 μm or less,
The release film for producing a ceramic green sheet according to any one of [1] to [5], wherein the maximum projection height (Sp) on the surface of the release layer is 100 nm or less.

[7] A method for manufacturing a ceramic green sheet by molding a ceramic green sheet using the release film for manufacturing a ceramic green sheet according to any one of [1] to [6], wherein the molded ceramic green sheet is A method for producing a ceramic green sheet having a thickness of 0.2 μm to 1.0 μm.

According to the present invention, it is possible to provide a release film for producing a ceramic green sheet which is excellent in release properties and which is less susceptible to transfer/drop-off of the release layer and poor adhesion.

[Release film for manufacturing ceramic green sheets]
The release film for producing a ceramic green sheet of the present invention (hereinafter sometimes simply referred to as "release film") has a polyester film and a release layer, and the release layer is provided on at least one side of the polyester film. It is sufficient if it is provided.

In addition, an easy-adhesion layer, an antistatic layer, a smoothing layer, etc. may be provided between the release layer and the polyester film. Good adhesion is easily obtained. That is, a preferred embodiment is a release film in which a release layer is provided directly on a polyester film.

The release layer comprises a polysiloxane A having two or more alkenyl groups in the molecule, a polysiloxane B having two or more hydrosilyl groups in the molecule, and an adhesion imparting agent C. A curable composition containing It is a hardened layer.

The release film of the present invention has the surface free energy γS (mJ/m ² ) of the surface of the release layer, i.e., the surface opposite to the polyester film of the release layer, and the hydrogen bond component γSVh (mJ/m ² ) of γS. ) satisfies the following formulas (a) and (b).
1.0≤γSVh/γS*100≤6.5 (a)
γS≦30 (b)
First, the surface properties of the release layer specified by formulas (a) and (b) will be described.

(Surface properties of release layer)
The above formulas (a) and (b) include the surface free energy γS and its hydrogen bond component γSVh, and how to obtain them will be explained. The surface free energy can be obtained by dropping each solvent such as water, methylene iodide, or ethylene glycol onto the release layer and measuring the angle (contact angle) between the droplet and the release layer after a certain period of time. . From the contact angle of each solvent, the surface free energy γS of the release layer and its hydrogen bond component γSVh are calculated using the Kitazaki-Hata equation.

More specifically, a release film is fixed on a flat glass substrate, and 1.9 μL of water is dropped onto the release film. 60 seconds after the droplet stops, the angle formed by the droplet and the release layer is measured and defined as _θ1 . Similarly, 0.9 μL of methylene iodide is dropped onto the release film. 30 seconds after the droplet has stopped, the angle formed by the droplet and the release layer is measured and defined as _θ2 . Furthermore, 0.9 μL of ethylene glycol is dropped onto the release film. 30 seconds after the droplet has stopped, the angle formed by the droplet and the release layer is measured and defined as _θ3 .

γLVnd, γLVnp, γLVnh, and γLn of water, methylene iodide, and ethylene glycol described in the above θ ₁ , θ ₂ , θ ₃ and Table 1 (where n = 1, 2, or 3; (corresponding to methylene chloride or ethylene glycol), the dispersion component γSVd, the dipole component γSVp, and the hydrogen bond component γSVh of the surface free energy of the release layer are calculated by the following Kitazaki-Hata formula, and the total is separated. It was defined as the surface free energy γs of the mold layer. That is, γSVd+γSVp+γSVh=γs. The unit of surface free energy and each component is "mJ/m ² ".

The present inventors have found that when the surface free energy obtained by measuring the release layer under the above conditions satisfies the formulas (a) and (b), the ceramic slurry is applied to the release layer and dried. The inventors have found that when the ceramic green sheet formed by the above method is peeled off, an extremely good peelability can be obtained. In addition, by satisfying the inequality on the lower limit side of the formula (a), the curability of the coating film is improved, and as a result, the release layer tends to have sufficient strength, and problems such as falling off of the release layer are less likely to occur. I found out.

It is believed that the excellent releasability from the ceramic green sheet described above is due to the fact that the surface free energy in the release layer has a small amount of hydrogen bonding components. That is, it is considered that the prevention of hydrogen bonding between the hydroxyl group component in the binder contained in the ceramic green sheet and the hydrogen component, which is an unreacted component in the release layer, contributes to the easy peelability of the ceramic green sheet.

4. The ratio of hydrogen bond components contained in the surface free energy of the release layer (γSVh/γS*100) is preferably 6.5% or less, more preferably 6.0% or less. It is more preferably 0% or less. When this ratio is 6.5% or less, the peel strength is good, and the ceramic green sheet is less likely to be deformed or damaged during peeling.

On the other hand, the lower limit of the ratio (γSVh/γS*100) is preferably 1.0% or more, more preferably 1.2% or more. When this ratio is 1.0% or more, the number of unreacted vinyl groups is small, the coating film tends to have sufficient strength, and problems such as detachment of the release layer are less likely to occur.

It is also desirable that the surface free energy γs of the release layer is low. This is because when the surface free energy of the release layer is close to the surface free energy of the ceramic green sheet, the energy required to separate the release layer from the ceramic green sheet increases, resulting in poor peelability. Conceivable. The surface free energy γs is desirably 30 mJ/m ² or less, more preferably 25 mJ/m ² or less, still more preferably 20 mJ/m ² or less.

The lower limit of the surface free energy γs is not particularly limited, but from the viewpoint of ceramic slurry coating properties, the surface free energy γs is preferably 12 mJ/m ² or more, more preferably 14 mJ/m ² or more. preferable.

[Release layer]
For the material constituting the release layer of the release film, it is preferable to use the curable composition shown below in order to form the release layer that satisfies the physical properties described above. That is, the release layer is preferably formed from a layer obtained by curing the curable composition shown below.

The curable composition contains polysiloxane A having two or more alkenyl groups in the molecule, polysiloxane B having two or more hydrosilyl groups in the molecule, and adhesion-imparting agent C.

(Polysiloxane A)
Polysiloxane A may have two or more alkenyl groups in side chains and/or terminals, preferably polyorganosiloxane having alkenyl groups in at least side chains, and polyorganosiloxane having alkenyl groups only in side chains. Siloxane is more preferred. Further, a copolymer containing a siloxane unit having an alkenyl group and a dialkylsiloxane unit or an alkylphenylsiloxane unit is preferable because it is easy to adjust the amount of alkenyl groups in one molecule while exhibiting releasability. . The terminal silicon atom is preferably a trialkylsilane structure such as trimethylsilane.

Examples of alkenyl groups include alkenyl groups having 2 or more and 10 or less carbon atoms. By having such an alkenyl group, the strength of the release layer is excellent. The alkenyl group is preferably an alkenyl group having 2 to 8 carbon atoms, more preferably an alkenyl group having 2 to 6 carbon atoms, and particularly preferably a vinyl group or a hexenyl group. A plurality of alkenyl groups may be bonded to a silicon atom to which an alkenyl group is bonded, but preferably an alkenyl group and an alkyl group are bonded. As the alkyl group in that case, a methyl group or the like is preferable.

In addition to the alkenyl group-containing siloxane units, the dialkylsiloxane units and the like contained in polysiloxane A are preferably exemplified by dimethylsiloxane units, phenylmethylsiloxane units, and the like.

Examples of polysiloxanes as described above include polysiloxanes represented by the following structural formula (1).

In the above formula (1), l, m and n are integers of 0 or more (where m+n is 2 or more). It is preferable because the cross-linking reaction proceeds favorably while exhibiting moldability, and the strength of the release layer is improved. From the same point of view, (m+n)/(l+m+n+2) is preferably 0.006 or more and 0.03 or less, more preferably 0.01 or more and 0.024 or less.

It should be noted that the above formula does not mean a block copolymer embodiment, but simply indicates that the total number of each unit is 1, m, and n. Therefore, the polysiloxane in the above formula may be a random copolymer or a block copolymer.

In the present invention, as the polysiloxane A, one type of polysiloxane as described above may be used alone, or a polysiloxane having two or more different alkenyl groups in one molecule may be used. Also, two or more polysiloxanes having different structures, such as having different alkenyl groups, may be used in combination.

The weight average molecular weight of polysiloxane A is preferably 300,000 or more and 600,000 or less, and particularly preferably 400,000 or more and 550,000 or less. In addition, the weight average molecular weight in this specification is the value of standard polystyrene conversion measured by the gel permeation chromatography (GPC) method.

When the weight-average molecular weight of polysiloxane A is 300,000 or more, the release layer after cross-linking has an appropriate coating film strength, which can more effectively prevent the coating film from coming off. Moreover, when the weight average molecular weight is 600,000 or less, the flatness of the coating film after drying is improved.

(Polysiloxane B)
Polysiloxane B may have two or more hydrosilyl groups (groups in which hydrogen atoms are directly bonded to silicon atoms) in side chains and/or terminals, and is hydrogen polysiloxane having hydrosilyl groups in at least side chains. is preferred, and hydrogenpolysiloxane having hydrosilyl groups only in side chains is more preferred. Further, a copolymer containing a siloxane unit having a hydrosilyl group and a dialkylsiloxane unit or an alkylphenylsiloxane unit is preferable because it is easy to adjust the amount of hydrosilyl groups in one molecule while exhibiting releasability. . A plurality of hydrogen atoms may be directly bonded to the silicon atom to which a hydrogen atom is directly bonded, but preferably a hydrogen atom and an alkyl group are bonded. As the alkyl group in that case, a methyl group or the like is preferable. The terminal silicon atom is preferably a trialkylsilane structure such as trimethylsilane.

In addition to the siloxane unit having a hydrosilyl group, the dialkylsiloxane unit and the like contained in the polysiloxane B are preferably exemplified by a dimethylsiloxane unit, a phenylmethylsiloxane unit, and the like.

Examples of such hydrogenpolysiloxanes include polysiloxanes represented by the following structural formula (2).

In the above formula (2), o is an integer of 0 or more and p is an integer of 2 or more. It is preferable because the cross-linking reaction proceeds favorably and the strength of the release layer is improved. From the same point of view, (p)/(o+p+2) is preferably 0.3 or more and 1 or less.

It should be noted that the above formula does not mean a block copolymer embodiment, but simply indicates that the total number of respective units is o and p. Therefore, the hydrogenpolysiloxane in the above formula may be a random copolymer or a block copolymer.

As the polysiloxane B, one of the above hydrogenpolysiloxanes may be used alone, or two or more hydrogenpolysiloxanes having different structures such as different numbers of hydrosilyl groups in one molecule may be used. They may be used together.

The weight average molecular weight of polysiloxane B is preferably 5,000 or more and 100,000 or less, and particularly preferably 7,000 or more and 20,000 or less. When the weight-average molecular weight of polysiloxane B is 5000 or more, the release layer after cross-linking has an appropriate coating film strength, making it possible to prevent the coating film from coming off. Moreover, when the weight average molecular weight is 100,000 or less, the flatness of the coating film after drying is improved.

In the present invention, polysiloxane A and polysiloxane B, preferably addition-polymerized in the presence of a platinum-based catalyst or the like, which will be described later, are the main components of the release layer. The addition polymerization here means that a functional group in a molecular terminal or a molecular side chain in polysiloxane A represented by ~Si-CH= _CH2 or ~Si-R-CH= _CH2 and H-Si~ It is a reaction in which the functional group in the molecular terminal or the molecular side chain in the polysiloxane B shown becomes -Si-CH ₂ CH ₂ -Si- or -Si-R-CH ₂ CH ₂ -Si-. However, "-" in the above functional groups indicates that the molecules are further connected. When the reaction at this time is expressed as a reaction formula, it is shown as the following formula. In addition, R represents a C1-C8 alkylene group here.

(Content of polysiloxane)
It is preferable that the molar ratio between the amount of hydrosilyl groups possessed by the polysiloxane B and the amount of alkenyl groups possessed by the polysiloxane A satisfies the following formula (c) in the curable composition.
1.0≤Si-H/Si-A≤3.8 (c)
(In the formula, Si—H represents the molar amount of hydrosilyl groups, and Si—A represents the molar amount of alkenyl groups.)

In other words, the release layer satisfies formula (a), and in order to satisfy this formula, it is preferable to adjust the amount of hydrosilyl groups possessed by polysiloxane B in the curable composition. It is desirable that the amount of hydrosilyl groups possessed by polysiloxane B is equal to the amount of alkenyl groups possessed by polysiloxane A and up to 3.8 times the molar amount. When the amount of hydrosilyl groups possessed by polysiloxane B is equal to or greater than the amount of alkenyl groups possessed by polysiloxane A, the coating film tends to have sufficient strength, and problems such as detachment of the release layer are less likely to occur. From this point of view, the molar ratio is more preferably 1.5 or more, and more preferably more than 2.0.

On the other hand, when the amount of hydrosilyl groups possessed by polysiloxane B is 3.8 times or less than the amount of alkenyl groups possessed by polysiloxane A, the amount of hydrogen bond components contained in the surface free energy of the release layer becomes appropriate, and the peelability is improved. become good. From this point of view, the molar ratio is more preferably 3.5 or less, and even more preferably 3.0 or less.

In the curable composition of the present invention, the mixing mass ratio (B/A) of polysiloxane A and polysiloxane B is preferably 0.5 or more and 5 or less, more preferably 0.9 or more and 3 or less. and preferably satisfies formula (c). By setting such a mixing mass ratio (B/A), the polysiloxane A and the polysiloxane B react appropriately, and it is possible to prevent either component from precipitating on the surface of the release layer.

(Adhesion imparting agent C)
The release layer in the present invention contains adhesion imparting agent C as an essential component. The adhesion-imparting agent tends to migrate between the polyester film and the release layer in the step of forming the release layer, thereby improving the adhesion between the polyester film and the release layer. As a result, it is possible to prevent the release layer from coming off from the polyester film in the process of processing the ceramic green sheet using the release film, resulting in a reduction in the defect rate in the production of the ceramic green sheet.

The adhesion-imparting agent desirably has a functional group that reacts with at least one of polysiloxane A or polysiloxane B in order to have adhesion to the silicone resin that is the release layer. Specifically, it preferably has one or more functional groups selected from the group consisting of vinyl groups, epoxy groups, acrylic groups, and methacrylic groups that react with hydrosilyl groups.

In addition, the adhesion imparting agent is desirably a silane coupling agent in order to impart adhesion to the polyester film. If it is a silane coupling agent, it becomes possible to impart good adhesiveness (for example, the effect of hydrogen bonding) to a polyester film while maintaining compatibility with polysiloxane.

As the silane coupling agent, those represented by the following general formula are preferable.

In the above general formula, X ¹ represents the above functional group, and a represents an integer of 1 or more and 3 or less. In particular, a is preferably 1.

R ¹ represents a hydrolyzable group selected from an alkoxy group, an acyloxy group, a halogen, or an alkyl group. Among them, an alkoxy group and an acyloxy group are preferable. As the alkoxy group, an alkoxy group having 1 to 10 carbon atoms is preferable, an alkoxy group having 1 to 6 carbon atoms is more preferable, and a methoxy group and an ethoxy group are particularly preferable. The acyloxy group is preferably an acyloxy group having 2 to 11 carbon atoms, more preferably an acyloxy group having 2 to 7 carbon atoms, and particularly preferably an acetoxy group. A chloro group is preferred as the halogen. As the alkyl group, an alkyl group having 1 to 6 carbon atoms is preferable.

When R ¹ is in the above aspect, the adhesiveness between the base film and the release layer is excellent.

In the above general formula, (4-a) R ^1s are bound to Si, and these R ^1s may be of the same type or of different types. may In the present invention, it is preferable that at least one of the (4-a) R ¹ 's is an alkoxy group or an acyloxy group, and it is more preferable that all R ¹ 's are an alkoxy group or an acyloxy group.

The silane coupling agents of the general formula may be used singly or in combination of two or more, and it is also possible to use a reactant obtained by reacting two or more silane coupling agents.

In addition, acetic acid, p-toluenesulfonic acid, or the like may be added to the silane coupling agent in order to improve the adhesion between the silane coupling agent and the polyester film.

The amount of the adhesion promoter added to the curable composition is desirably 1% by mass or more and 10% by mass or less, more preferably 2., based on the total amount of polysiloxane A and polysiloxane B. It is desirable to be 0% by mass or more and 8.0% by mass or less. When it is 1% by mass or more, the adhesion between the release layer and the substrate is good, and when it is 10% by mass or less, excessive adhesion The property-imparting agent is less likely to adversely affect the release layer, resulting in good flatness and releasability.

(Catalyst D)
The curable composition for forming the release layer preferably further contains a catalyst D. The catalyst is not particularly limited as long as it can accelerate the curing reaction of the curable composition, but platinum group metal compounds are preferred.

Examples of platinum group metal compounds include fine particle platinum, fine particle platinum adsorbed on a carbon powder carrier, chloroplatinic acid, alcohol-modified chloroplatinic acid, olefin complexes of chloroplatinic acid, palladium, rhodium, and the like. . When the curable composition contains such a catalyst, the curing reaction of the curable composition can proceed more efficiently.

The content of the catalyst D in the curable composition according to the present embodiment is about 1 ppm or more and 1000 ppm or less with respect to the total amount of solids other than the catalyst D from the viewpoint of adjusting the curing reaction rate to a suitable range. is preferred.

(Optional component)
In addition to the above components, the curable composition may contain a reaction inhibitor, a solvent, a silicone resin having no reactive functional group, an antistatic agent, and the like.

(Physical properties of release layer)
The thickness of the release layer is preferably 0.005 μm or more and 0.1 μm or less, and more preferably 0.01 μm or more and 0.05 μm or less. When the thickness of the release layer is 0.005 μm or more, the thickness is sufficient to exhibit the function as a release layer. On the other hand, when the thickness of the release layer is 0.1 μm or less, the coating film is less likely to come off from the release layer.

The surface of the release layer is desirably flat so as not to cause defects in the ceramic green sheet coated and molded thereon. ) is preferably 100 nm or less. More preferably, the average surface roughness of the region is 5 nm or less and the maximum projection height is 80 nm or less. For example, the maximum protrusion height (Sp) may be 45 nm or less.

If the surface roughness of the region is 7 nm or less and the maximum protrusion height is 100 nm or less, defects such as pinholes do not occur when forming the ceramic green sheet, and the yield is favorable, which is preferable. It can be said that the smaller the region surface average roughness (Sa) is, the more preferable it is. It can be said that the smaller the maximum protrusion height (Sp) is, the more preferable it is, but the maximum protrusion height (Sp) may be 1 nm or more, or 3 nm or more.

[Polyester film]
The polyester film used as the base film (hereinafter sometimes referred to as base film) in the present invention is a film containing polyester as a resin component, and preferably contains the most polyester in the resin component (for example, 90 mass % or more).

The polyester that constitutes the polyester film is not particularly limited, and it is possible to use a film formed from polyester that is commonly used as a release film base material. Preferred are crystalline linear saturated polyesters comprising an aromatic dibasic acid component and a diol component, such as polyethylene terephthalate, polyethylene-2,6-naphthalate, polybutylene terephthalate, polytrimethylene terephthalate, or resins thereof. Copolymers based on constituents are more preferred.

A polyester film formed from polyethylene terephthalate is particularly suitable. The polyethylene terephthalate preferably contains 90 mol % or more, more preferably 95 mol % or more of repeating units of ethylene terephthalate, and may be copolymerized with other dicarboxylic acid components and diol components in small amounts. For example, from the viewpoint of cost, one produced only from terephthalic acid and ethylene glycol is preferable. In addition, known additives such as antioxidants, light stabilizers, ultraviolet absorbers, crystallization agents, etc. may be added within limits that do not impair the effects of the release film of the present invention. The polyester film is preferably a biaxially oriented polyester film because of its high bidirectional elastic modulus.

The intrinsic viscosity of the polyethylene terephthalate film is preferably 0.50 dl/g or more and 0.70 dl/g or less, more preferably 0.52 dl/g or more and 0.62 dl/g or less. When the intrinsic viscosity is 0.50 dl/g or more, it is preferable because many breakages do not occur in the stretching process. Conversely, when it is 0.70 dl/g or less, the cutting performance is good when cutting into a predetermined product width, and dimensional defects do not occur, which is preferable. Moreover, it is preferable to sufficiently vacuum-dry the raw material pellets.

In the present specification, the term "polyester film" may mean a (laminated) polyester film having a surface layer A and a surface layer B.

The method for producing the polyester film in the present invention is not particularly limited, and conventionally commonly used methods can be used. For example, the polyester can be melted by an extruder, extruded into a film, cooled by a rotating cooling drum to obtain an unstretched film, and biaxially stretched to obtain the unstretched film. The biaxially stretched film can be obtained by a method of sequentially biaxially stretching a longitudinally or laterally uniaxially stretched film in the lateral direction or longitudinal direction, or by a method of simultaneously biaxially stretching an unstretched film in the longitudinal direction and the lateral direction. I can.

In the present invention, the stretching temperature during stretching of the polyester film is preferably at least the secondary transition point (Tg) of the polyester. It is preferable that the film is stretched 1- to 8-fold, particularly 2- to 6-fold, in each of the longitudinal and transverse directions.

The thickness of the polyester film is preferably 12 µm or more and 50 µm or less, more preferably 15 µm or more and 38 µm or less, and still more preferably 19 µm or more and 33 µm or less. If the thickness of the film is 12 μm or more, it is preferable because there is no risk of deformation due to heat during film production, processing, and molding. On the other hand, if the thickness of the film is 50 μm or less, the amount of the film to be discarded after use is not excessively increased, which is preferable for reducing the environmental load.

The above polyester film substrate may be a single layer or a multilayer of two or more layers. For example, the base film may be a polyester film having a surface layer A substantially free of particles with a particle size of 1.0 μm or more and a surface layer B containing particles. Preferably, the surface layer A does not substantially contain inorganic particles having a particle size of 1.0 μm or more.

In this aspect, the surface layer A may contain particles with a particle size of less than 1.0 μm and 1 nm or more. When the surface layer A does not substantially contain particles having a particle size of 1.0 μm or more, such as inorganic particles, it is possible to reduce the occurrence of problems due to transfer of the particle shape in the base material to the resin sheet.

In one aspect, the surface layer A does not contain particles with a particle size of less than 1.0 μm, so that it is possible to more effectively suppress the transfer of the particle shape in the base material to the resin sheet and the occurrence of problems.

In one aspect, the polyester film substrate is preferably a laminated film having a surface layer A substantially free of inorganic particles on at least one side. As a result, it is possible to more effectively suppress the transfer of the particle shapes in the base material to the resin sheet and the occurrence of problems.

For example, it is preferable that the surface layer A, which does not substantially contain particles with a particle size of less than 1.0 μm, substantially does not contain particles with a particle size of 1.0 μm or more.

Here, in the present invention, “substantially free of particles” means, for example, in the case of inorganic particles of less than 1.0 μm, when the inorganic elements are quantified by fluorescence X-ray analysis, it is 50 ppm or less, preferably 10 ppm. Hereinafter, most preferably, it means a content below the detection limit. Even if particles are not actively added to the film, contaminants derived from foreign substances and dirt adhering to the raw material resin or the lines and equipment in the film manufacturing process peel off and enter the film. This is because Further, "substantially free of particles with a particle size of 1.0 μm or more" means that particles with a particle size of 1.0 μm or more are intentionally not included.

In the case of a laminated polyester film having a multilayer structure of two or more layers, it is preferable to have a surface layer B that can contain inorganic particles, etc. on the opposite side of the surface layer A that does not substantially contain inorganic particles.

As a laminated structure, the layer on the side where the release layer is applied is layer A, the layer on the opposite side is layer B, and the core layer other than these is layer C. The layer configuration in the thickness direction is release layer / A / B, or a laminated structure such as release layer/A/C/B. Of course, the C layer may have a multi-layer structure. In addition, the surface layer B may not contain inorganic particles. In that case, it is preferable to provide a coating layer D containing at least inorganic particles and a binder on the surface layer B in order to impart lubricity for winding the film into a roll.

In the polyester film substrate of the present invention, the surface layer B, which forms the surface opposite to the surface to which the release layer is applied, preferably contains inorganic particles from the viewpoint of film slipperiness and ease of air release. In particular, silica particles and/or calcium carbonate particles are preferably used. The content of the inorganic particles contained in the surface layer B is preferably 5000 ppm or more and 15000 ppm or less in total of the inorganic particles.

At this time, the area surface average roughness (Sa) of the film of the surface layer B is preferably in the range of 1 nm or more and 40 nm or less. More preferably, it is in the range of 5 nm or more and 35 nm or less. When the total amount of silica particles and/or calcium carbonate particles is 5000 ppm or more and Sa is 1 nm or more, when the film is wound into a roll, air can be released uniformly, resulting in a good roll shape and good flatness. , suitable for the production of ultra-thin ceramic green sheets. In addition, when the total amount of silica particles and/or calcium carbonate particles is 15000 ppm or less and Sa is 40 nm or less, aggregation of the lubricant is difficult to occur and coarse protrusions cannot be formed, so that the quality is stable when manufacturing an ultra-thin ceramic green sheet. and preferred.

As the particles contained in the B layer, inactive inorganic particles and/or heat-resistant organic particles can be used in addition to silica and/or calcium carbonate. More preferably, calcium carbonate particles are used. Inorganic particles that can also be used include alumina-silica composite oxide particles, hydroxyapatite particles, and the like. Examples of 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. If 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 size is 2.0 μm or less, there is no fear of adversely affecting the smoothness of the surface of the release layer, and thus there is no fear of generating pinholes in the ceramic green sheet, which is preferable. The average particle diameter of the particles is measured by observing the cross section of the film after processing with a scanning electron microscope, observing 100 particles, and taking the average value as the average particle diameter. can be done. The shape of the particles is not particularly limited as long as it satisfies the object of the present invention, and spherical particles and irregularly shaped non-spherical particles can be used. The particle diameter of amorphous particles can be calculated as a circle equivalent diameter. The circle-equivalent diameter is a value obtained by dividing the observed particle area by the circular constant (π), calculating the square root, and doubling the result.

From the viewpoint of reducing pinholes, it is preferable not to use recycled raw materials for the surface layer A, which is the layer on which the release layer is provided, in order to prevent contamination of inorganic particles such as lubricants.

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 layer thickness of the base film. If it is 20% or more, the inside of the film is less likely to be affected by the particles contained in the surface layer B, etc., and it is easy for the region surface average roughness Sa to satisfy the above range, which is preferable. When the total thickness of the base film is 50% or less of the total thickness 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.

In addition, from the viewpoint of economy, it is possible to use 50% by mass or more and 90% by mass or less of recycled film scraps or PET bottle raw materials for layers other than the surface layer A (surface layer B or intermediate layer C). can. Even in this case, the type and amount of the lubricant contained in the B layer, the particle size, and the area surface average roughness (Sa) preferably satisfy the above ranges.

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

When the surface layer B does not contain particles, it is also preferable that the surface layer B is coated with a coating layer D containing particles to provide lubricity. The means for providing the main coat layer D is not particularly limited, but it is preferably provided by a so-called in-line coating method in which coating is performed during film formation of the polyester film. Further, in the case of providing a coating layer D that provides slipperiness on the surface of the polyester film on which the release layer is not laminated, the polyester film does not need to have the surface layers A and B, and inorganic particles are not included. It may consist of a single-layer polyester film that does not contain substantially.

The area surface average roughness (Sa) of the surface layer B is preferably 40 nm or less, more preferably 35 nm or less, and still more preferably 30 nm or less. In addition, when the surface layer B or the surface of the single-layer polyester film on which the release layer is not laminated is provided with a coat layer D to give slipperiness, the surface Sa is measured on the surface on which the coat layer D is laminated. However, it is preferably in the same range as the region surface average roughness (Sa) of the surface layer B described above.

It is preferable that at least a binder resin and particles are contained in the coat layer D on the side of the polyester film on which the release layer is not laminated.

(Binder resin for coat layer D)
The binder resin constituting the easy-smooth coating layer is not particularly limited, but specific examples of polymers include polyester resins, acrylic resins, urethane resins, polyvinyl resins (polyvinyl alcohol, etc.), polyalkylene glycol, polyalkyleneimine, and methyl cellulose. , hydroxycellulose, starches, and the like. Among these resins, polyester resins, acrylic resins, and urethane resins are preferably used from the viewpoint of particle retention and adhesion. In addition, polyester resin is particularly preferable in consideration of compatibility with the polyester film. In order to achieve solubility in solvents, dispersibility, and adhesiveness to the substrate film and other layers, the binder polyester is preferably a copolymerized polyester. Incidentally, the polyester resin may be modified with polyurethane. Urethane resin is another preferable binder resin that constitutes the easy-slip coating layer on the polyester base film. Urethane resins include polycarbonate polyurethane resins. Furthermore, polyester resins and polyurethane resins may be used in combination, and other binder resins may be used in combination.

(Crosslinking agent for coat layer D)
In the present invention, the slippery coating layer may contain a cross-linking agent to form a crosslinked structure in the slippery coating layer. By containing a cross-linking agent, it becomes possible to further improve adhesion under high temperature and high humidity conditions. Specific cross-linking agents include urea-based, epoxy-based, melamine-based, isocyanate-based, oxazoline-based, carbodiimide-based, aziridine and the like. In addition, a catalyst or the like can be appropriately used as necessary in order to accelerate the cross-linking reaction.

(Particles in Coat Layer D)
The easy-slip coating layer preferably contains lubricant particles in order to impart slipperiness to the surface. The particles may be inorganic particles or organic particles, and are not particularly limited, and include (1) silica, kaolinite, talc, light calcium carbonate, heavy calcium carbonate, zeolite, alumina, Barium sulfate, carbon black, zinc oxide, zinc sulfate, zinc carbonate, zirconium oxide, titanium dioxide, satin white, aluminum silicate, diatomaceous earth, calcium silicate, aluminum hydroxide, hydrated halloysite, calcium carbonate, magnesium carbonate, calcium phosphate, hydroxide inorganic particles such as magnesium and barium sulfate; Examples include organic particles such as isoprene, methyl methacrylate/butyl methacrylate, melamine, polycarbonate, urea, epoxy, urethane, phenol, diallyl phthalate, and polyester. Silica is particularly preferably used to impart lubricity.

The average particle size of the particles is preferably 10 nm or more, more preferably 20 nm or more, and still more preferably 30 nm or more. When the average particle size of the particles is 10 nm or more, it is preferable because the particles are less likely to aggregate and the lubricity can be ensured.

The average particle size of the particles is preferably 1000 nm or less, more preferably 800 nm or less, and even more preferably 600 nm or less. When the average particle diameter of the particles is 1000 nm or less, the transparency is maintained and the particles do not fall off, which is preferable.

Further, for example, a mixture of small particles having an average particle diameter of about 10 nm or more and 270 nm or less and large particles having an average particle diameter of about 300 nm or more and 1000 nm or less can also be used, which will be described later. It is preferable to reduce the average length (RSm) of the roughness curve element while keeping the roughness (RP) small, and to achieve both slipperiness and smoothness, particularly preferably small particles of 30 nm or more and 250 nm or less, It is to use large particles having an average particle size of 350 nm or more and 600 nm or less. When small particles and large particles are mixed, it is preferable that the mass content of small particles is larger than the mass content of large particles with respect to the total solid content of the coating layer.

[Formation of release layer]
In the present invention, the method for forming the release layer is not particularly limited. is removed by drying and then cured.

When the release layer of the present invention is applied onto a substrate film by solution coating, the drying temperature for solvent drying is preferably 50° C. or higher and 120° C. or lower, and preferably 60° C. or higher and 100° C. or lower. more preferred. The drying time is preferably 30 seconds or less, more preferably 20 seconds or less. Furthermore, after drying the solvent, it is preferable to irradiate the active energy ray to advance the curing reaction. As the active energy ray used at this time, an ultraviolet ray, an electron beam, an X-ray, or the like can be used, but the ultraviolet ray is preferable because it is easy to use. The amount of ultraviolet light to be irradiated is preferably 30 mJ/cm ² or more and 300 mJ/cm ² or less, more preferably 30 mJ/cm ² or more and 200 mJ/cm ² or less. When it is 30 mJ/cm ² or more, the curing of the composition proceeds sufficiently, and when it is 300 mJ/cm ² or less, the processing speed can be improved, so that the release film can be produced economically. preferable.

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

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

[Ceramic green sheet]
The release film for producing ceramic green sheets of the present invention is suitably used for producing ceramic green sheets. Further, the method for producing a ceramic green sheet of the present invention is a method for producing a ceramic green sheet by molding a ceramic green sheet using the release film described above. It is characterized by having a thickness of ˜1.0 μm.

The ceramic green sheet is not particularly limited as long as it contains ceramic. In one aspect, the release film of the present invention is a release film for molding a ceramic green sheet containing an inorganic compound. Examples of inorganic compounds include metal particles, metal oxides, and minerals, such as calcium carbonate, silica particles, aluminum particles, and barium titanate particles. Since the present invention has a release layer with high smoothness, even in an embodiment in which these inorganic compounds are included in the ceramic green sheet, defects attributable to the inorganic compound, such as breakage of the ceramic green sheet, from the release layer It is possible to suppress the problem that the separation of the ceramic green sheet becomes difficult.

The resin component that forms the ceramic green sheet can be appropriately selected according to the application. In one aspect, the ceramic green sheet containing the inorganic compound is a ceramic green sheet. For example, the ceramic green sheets can contain barium titanate as the inorganic compound. Moreover, as a resin component, for example, a polyvinyl butyral-based resin can be included.

In one aspect, the ceramic green sheet has a thickness of 0.2 μm or more and 1.0 μm or less.

For example, the present invention can provide a method for producing a release film for producing a ceramic green sheet containing such an inorganic compound. In addition, the method for producing a release film in the present invention may include a step of forming a ceramic green sheet having a thickness of 0.2 μm or more and 1.0 μm or less.

[Ceramic green sheets and ceramic capacitors]
Generally, a multilayer 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 internal electrode is exposed on the first end face of the ceramic body. A first external electrode is provided on the first end surface. The first internal electrode is electrically connected to the first external electrode at the first end surface. The second internal electrode is exposed on the second end face of the ceramic body. A second external electrode is provided on the second end surface. The second internal electrode is electrically connected to the second external electrode at the second end surface.

In one aspect, the release film of the present invention is a release film and is used to produce such a laminated ceramic capacitor.

For example, a ceramic green sheet manufacturing method for molding a ceramic green sheet using the release film of the present invention can mold a ceramic green sheet having a thickness of 0.2 μm or more and 1.0 μm or less.

More specifically, for example, ceramic green sheets are 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, an extremely thin product of 0.2 μm or more and 1.0 μm or less is required. A conductive layer for forming the first or second internal electrode is printed on the coated and dried ceramic green sheet. Ceramic green sheets, ceramic green sheets printed with conductive layers for forming first internal electrodes, and ceramic green sheets printed with conductive layers for forming second internal electrodes are appropriately laminated and pressed. Thus, a mother laminate is obtained. The mother laminate is divided into a plurality of pieces to produce raw ceramic bodies. A ceramic body is obtained by firing a raw ceramic body. After that, the multilayer ceramic capacitor can be completed by forming the first and second external electrodes.

The present invention will be described more specifically below with examples and comparative examples. In addition, in the present invention, physical properties were measured or evaluated by the following methods. Hereinafter, "parts" means "parts by mass" and "%" means "% by mass" unless otherwise specified.

(Functional group content of polysiloxane mixture)
Deuterated chloroform was added to a silicone mixture having the same mixing ratio as the polysiloxanes A and B to be used and dissolved so that the solid content was 10% by mass, and the resulting mixture was placed in an NMR tube. The sample placed in the NMR tube was subjected to NMR measurement using a nuclear magnetic resonance apparatus (manufactured by BRUKER, NMR AVANCE NEO 600) to quantify the amount (mmol) of each functional group of alkenyl groups and hydrosilyl groups.

From the above measurement results, the molar ratio of alkenyl groups to hydrosilyl groups was calculated using the following formula.
Molar ratio = Si-H/Si-A
(In the formula, Si—H represents the molar amount of hydrosilyl groups, and Si—A represents the molar amount of alkenyl groups.)

(Weight average molecular weight)
A sample solution adjusted to a sample concentration of 0.2% was filtered through a 0.2 μm membrane filter and subjected to gel permeation chromatography (GPC) analysis under the following conditions to determine the weight average molecular weight. The molecular weight was calculated in terms of standard polystyrene.
Apparatus: TOSOH HLC-8320GPC
Column: TSKgel SuperHM-H×2 + TSKgel SuperH2000 (TOSOH)
Solvent: 100% chloroform
Flow rate: 0.6ml/min
Concentration: 0.2%
Injection volume: 20 μl
Temperature: 40°C
Detector: RI

(Release layer thickness)
The release film was embedded in a resin and cut into ultrathin slices using an ultramicrotome. After that, cross-sectional observation was performed using a JEOL JEM2100 transmission electron microscope, and the film thickness of the release layer was measured from the observed TEM image. When the thickness was too thin to be evaluated accurately by cross-sectional observation, the Si intensity was measured with a fluorescent X-ray device (ZSX PRIMUS II manufactured by Rigaku), and the coating amount was calculated by the calibration curve method.

(Release layer region surface average roughness Sa, maximum protrusion height Sp)
Using a non-contact surface profile measurement system (VertScan R550H-M100), measurements were made under the following conditions. The area surface average roughness (Sa) adopts the average value of 5 measurements, and the maximum protrusion height (Sp) is measured 7 times, and the maximum value among the 5 measurement results excluding the maximum and minimum values adopted the one of

(Measurement condition)
・Measurement mode: WAVE mode ・Objective lens: 50x ・0.5×Tube lens ・Measurement area: 187 μm×139 μm
(analysis conditions)
・Surface correction: Quaternary correction ・Interpolation processing: Complete interpolation

(Surface free energy of release layer)
Fix the release film on a flat glass substrate, drop 1.9 μL of water on the release film using a contact angle meter (Kyowa Interface Chemical DM-501), and after 60 seconds when the droplet has stopped, the liquid The angle formed by the droplet and the release layer was measured, and the average value of 5 measurements was taken as θ ₁ . Similarly, 0.9 μL of methylene iodide was dropped on the release film, and 30 seconds after the droplet stopped, the angle formed by the droplet and the release layer was measured, and the average value of 5 measurements was taken as _θ2 . . Further, 0.9 μL of ethylene glycol was dropped on the release film, and 30 seconds after the droplet stopped standing _, the angle formed by the droplet and the release layer was measured.

γLVnd, γLVnp, γLVnh, and γLn of water, methylene iodide, and ethylene glycol described in the above θ ₁ , θ ₂ , θ ₃ and Table 2 (where n = 1, 2 or 3, water, iodide corresponding to methylene or ethylene glycol), the dispersion component γSVd, the dipole component γSVp, and the hydrogen bond component γSVh of the surface free energy of the release layer are calculated by the following formula, and the total is the surface of the release layer Free energy γS. The unit of surface free energy and each component is "mJ/m ² ".

γSVd + γSVp + γSVh = γS
(Peel force of ceramic sheet)
A slurry composition I consisting of the following materials was stirred and mixed for 10 minutes, and dispersed for 10 minutes with zirconia beads having a diameter of 0.5 mm using a bead mill to obtain a primary dispersion. After that, a slurry composition II consisting of the following materials was added to the primary dispersion at a ratio of (slurry composition I): (slurry composition II) = 3.4: 1.0, and a bead mill was used to prepare a slurry having a diameter of 0. Secondary dispersion was carried out for 10 minutes with 0.5 mm zirconia beads to obtain a ceramic slurry.
(Slurry composition I)
Toluene 22.3 parts by mass Ethanol 18.3 parts by mass Barium titanate (average particle diameter 100 nm) 57.5 parts by mass Homogenol L-18 (manufactured by Kao Corporation) 1.9 parts by mass (Slurry composition II)
Toluene 39.6 parts by mass Ethanol 39.6 parts by mass Dioctyl phthalate 3.3 parts by mass Polyvinyl butyral (S-Lec BM-S, manufactured by Sekisui Chemical Co., Ltd.) 16.3 parts by mass 1-Ethyl-3-methylimidazolium ethyl sulfate 0 .5 parts by mass Next, the release surface of the release film sample obtained was coated with an applicator so that the slurry after drying was 1.0 μm, dried at 60 ° C. for 1 minute, and the release film with the ceramic green sheet was applied. A mold film was obtained. After the release film with the resulting ceramic green sheet was statically eliminated using a static eliminator (manufactured by Keyence Corporation, SJ-F020), a peel tester (manufactured by Kyowa Interface Science Co., Ltd., VPA-3, load cell load 0.1N) was used. It was peeled at a peeling angle of 90 degrees, a peeling temperature of 25°C, and a peeling speed of 10 m/min. As for the peeling direction, a double-sided adhesive tape (manufactured by Nitto Denko Co., Ltd., No. 535A) was attached to the SUS plate attached to the peel tester, and the ceramic green sheet side was adhered to the double-sided tape on the release film. was fixed and peeled off by pulling the release film side. Among the obtained measured values, the average value of the peel force at the peel distance of 20 mm or more and 70 mm or less was calculated, and the value was defined as the peel force. The measurement was performed a total of 5 times, and the average value of the peel strength was adopted.

(Evaluation of pinholes in ceramic green sheets)
A ceramic green sheet having a thickness of 1 μm was formed on the release surface of the release film in the same manner as in the evaluation of the peel strength of the ceramic sheet. Next, the release film was peeled off from the molded release film with the ceramic green sheet to obtain a ceramic green sheet. In the central region of the obtained ceramic green sheet in the film width direction, light was applied from the opposite side of the ceramic slurry-coated surface in a range of 25 cm ² , and the occurrence of pinholes that can be seen through light transmission was observed. judged visually.
○: No pinholes ×: One or more pinholes

(Si transfer amount to PVB sheet)
Polyvinyl butyral (S-lec BM-S manufactured by Sekisui Chemical Co., Ltd.) is applied to the release surface of the release film sample using an applicator so that the thickness of the resin after drying is 1.0 μm, and dried at 60 ° C. for 1 minute. Then, a release film with a PVB sheet was obtained. After the release film with the PVB sheet was allowed to stand in an environment of 23°C and 65RH for 24 hours, the PVB sheet was peeled off from the release film, and the surface of the PVB sheet in contact with the release film was exposed to a fluorescent X-ray device (ZSX PRIMUSII manufactured by Rigaku). ) was used to measure the Si intensity (Kcps).

(Set-off of release layer to polyester substrate)
The release film sample was cut into 6 sheets of 5 cm×5 cm, 6 sheets were stacked so that the release surface and the surface opposite to the release surface were in contact, and pressure treatment was performed for 10 minutes while a load of 30 MPa was applied. After that, the six release films were peeled off, and the surface opposite to the release surface of the six films was painted red with a red marker pen (MGD-T2 manufactured by Teranishi Kagaku Kogyo Co., Ltd.) to check whether the marker ink repelled.
○: 0 cissing points on all 6 sheets ×: 1 or more cissing points on any of the 6 sheets

(Adhesion of release layer over time)
After storing the release film sample in an environment of 60°C and 90% RH for 3 days, gauze (white cross Pearl paper (Toyobo Ester Film P4255-35 manufactured by Toyobo Co., Ltd.) is used through Hakujuji Gauze Co., Ltd.), the load on the head is 200 gf / 25 mm ² (5 mm × 5 mm) [0.0785 MPa], and the film was reciprocated 10 times to rub against the load head, and then the release surface was painted red with a red marker pen (MGD-T2 manufactured by Teranishi Kagaku Kogyo Co., Ltd.) to confirm whether the marker ink was repelled.
〇: Magic ink repels △: There are parts where magic ink does not repel ×: Magic ink does not repel

(Preparation of polyethylene terephthalate pellets (PET (I)))
As the esterification reactor, a continuous esterification reactor comprising a three-stage complete mixing tank having a stirrer, a partial condenser, a raw material inlet and a product outlet was used. TPA (terephthalic acid) was adjusted to 2 tons/hour, EG (ethylene glycol) was adjusted to 2 mol per 1 mol of TPA, and antimony trioxide was adjusted to give an amount of Sb atoms of 160 ppm relative to the produced PET. It was continuously supplied to the first esterification reactor of the reaction apparatus and reacted at 255° C. for an average residence time of 4 hours under normal pressure. Next, the reaction product in the first esterification reaction can is continuously taken out of the system and supplied to the second esterification reaction can, and distilled from the first esterification reaction can into the second esterification reaction can. 8 mass % of EG is supplied to the produced PET, and further, an EG solution containing magnesium acetate tetrahydrate in an amount such that the Mg atom is 65 ppm relative to the produced PET, and an EG solution containing 40 ppm of P atom relative to the produced PET. An EG solution containing TMPA (trimethyl phosphate) in an amount corresponding to the above was added and reacted at 260° C. under normal pressure for an average residence time of 1 hour. Next, the reaction product in the second esterification reactor was continuously taken out of the system, supplied to the third esterification reactor, and subjected to 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 having an average particle size of 0.9 μm, which has been subjected to dispersion treatment for an average of 5 passes at a pressure of , and 1% by mass of ammonium salt of polyacrylic acid per calcium carbonate. While adding 0.4% by mass of synthetic calcium carbonate with a diameter of 0.6 μm as a 10% EG slurry, the mixture was reacted at normal pressure at 260° C. for an average residence time of 0.5 hours. The esterification reaction product produced in the third esterification reaction vessel was continuously supplied to a three-stage continuous polycondensation reactor for polycondensation to sinter stainless steel fibers having a 95% cut diameter of 20 μm. After filtration with a filter, ultrafiltration was performed, the product was extruded into water, and after cooling, it was cut into chips to obtain PET chips having an intrinsic viscosity of 0.60 dl/g (hereinafter abbreviated as PET (I)). . The lubricant content in the PET chip was 0.6% by mass.

(Preparation of polyethylene terephthalate pellets (PET (II)))
On the other hand, in the production of the PET(I) chip, a PET chip with an intrinsic viscosity of 0.62 dl/g containing no particles such as calcium carbonate and silica was obtained (hereinafter abbreviated as PET(II)).

(Production of laminated film X1)
After drying these PET chips, they were melted at 285° C. and melted at 290° C. by a separate melt extruder extruder to filter sintered stainless steel fibers with a 95% cut diameter of 15 μm and Two-stage filtration of sintered 15 μm stainless steel particles is performed, and they are combined in the feed block to form PET (I) on the surface layer B (anti-releasing surface side layer) and PET (II) on the surface. Laminated so as to form layer A (releasing surface side layer), extruded (cast) into a sheet at a speed of 45 m / min, electrostatically adhered on a casting drum at 30 ° C. by an electrostatic adhesion method, cooled, An unstretched polyethylene terephthalate sheet having an intrinsic viscosity of 0.59 dl/g was obtained. The layer ratio was adjusted so that PET (I)/(II)=60% by mass/40% by mass in calculating the discharge amount of each extruder. Then, the unstretched sheet was heated with an infrared heater and then stretched 3.5 times in the machine direction at a roll temperature of 80° C. due to the speed difference between the rolls. After that, it was led to a tenter and stretched 4.2 times in the transverse direction at 140°C. It was then heat treated at 210° C. in a heat setting zone. After that, a 2.3% relaxation treatment was applied in the transverse direction at 170° C. to obtain a biaxially stretched polyethylene terephthalate film X1 having a thickness of 31 μm. The Sa of the surface layer A of the obtained film X1 was 1 nm, and the Sa of the surface layer B was 28 nm.

(Production of laminated film X2)
As the laminated film X2, both the surface layer A side and the surface layer B side are laminated in the same manner as the laminated film X1 using PET (II), extruded (casting) into a sheet at a speed of 45 m / min, and statically. Electrostatic adhesion was carried out on a casting drum at 30° C. by an electroadhesion method, followed by cooling to obtain an unstretched polyethylene terephthalate sheet having an intrinsic viscosity of 0.59 dl/g. This unstretched PET sheet was heated to 100° C. by a heated roll group and an infrared heater, and then stretched 3.5 times in the longitudinal direction by a roll group with a peripheral speed difference to obtain a uniaxially stretched PET film. Next, after coating the following slippery coating liquid on one side of the PET film with a bar coater, it was dried at 80° C. for 15 seconds. The coating amount after the final stretching and drying was adjusted to 0.1 μm. Subsequently, the film was stretched 4.0 times in the width direction at 150°C with a tenter, heated at 230°C for 0.5 seconds while fixing the length of the film in the width direction, and further heated at 230°C for 10 seconds 3. % in the width direction to obtain an in-line coated polyester film with a thickness of 31 μm. The Sa of the surface layer A of the obtained film X2 was 1 nm, and the Sa of the surface layer B was 14 nm.

(Smooth coating liquid)
Water 45.82 parts by mass Isopropyl alcohol 35.00 parts by mass Acrylic polyol resin 10.36 parts by mass (DSM Coating Resins NeoCryl A-614, Tg 74°C, acid value 55%, solid content concentration 32% by mass)
Oxazoline-based cross-linking agent D-1 5.68 parts by mass (solid content concentration 25% by mass)
Acrylic particle water dispersion 2.37 parts by mass (manufactured by Nippon Shokubai, trade name MX200W, average particle size 350 nm, solid content concentration 10% by mass)
Acrylic particle water dispersion 0.47 parts by mass (manufactured by Nippon Shokubai, trade name MX300W, average particle size 450 nm, solid content concentration 10% by mass)
Surfactant H-1 (fluorine-based, solid content concentration 10% by mass) 0.30 parts by mass

(Example 1)
As polysiloxane A, a vinyl-modified silicone resin represented by structural formula (1) (weight average molecular weight: 466000, l = 3120, m = 46, n = 0 in structural formula (1)) and polysiloxane B, structure Polymethylhydrogensiloxane represented by formula (2) (weight average molecular weight: 8400, o = 3, p = 65 in structural formula (2)) at a molar ratio (hydrosilyl group weight/alkenyl group weight) of 2. A silicone mixture R1 adjusted to 0 was prepared, and the following release layer forming coating solution M1 containing the silicone mixture R1, adhesion imparting agent S1, and catalyst P1 was prepared.
(Release layer forming coating liquid M1)
Methyl ethyl ketone 64.3 parts Toluene 34.0 parts Silicone mixture R1 1.5 parts Adhesion imparting agent S1 0.083 parts (SD7200 manufactured by Dow Toray Industries, Inc. (reaction product of vinyltriacetoxysilane and glycidoxypropyltrimethoxysilane Solid concentration 90%))
Catalyst P1 0.1 parts (SRX212 manufactured by Dow Toray Industries, Inc. (platinum complex of 1,1,3,3-tetramethyl-1,3-divinyldisiloxane, solid content concentration 5%))
The release layer forming coating solution M1 having the composition described above was applied onto the surface layer A of the laminated film X1 using reverse gravure so that the coating amount after drying was 0.020 μm. After that, the processing speed was adjusted so that the first drying furnace entered after 0.5 seconds, and heat drying was continuously performed at a first drying furnace temperature of 120°C and a second drying furnace temperature of 90°C. After the drying process, an ultraviolet irradiator (manufactured by Heraeus, H bulb) is used to irradiate ultraviolet light with an integrated light amount of 100 mJ/cm ² on a cooling roll to cure the release layer, thereby forming a mold for manufacturing a ceramic green sheet. got the film. Table 3 shows an overview of the release layer-forming coating solution and the laminated film used at that time. Table 4 shows the results of evaluation of various physical properties of the obtained release film.

(Example 2)
As polysiloxane A, a vinyl-modified silicone resin represented by structural formula (1) (weight average molecular weight: 495000, l = 2820, m = 60, n = 0 in structural formula (1)), and as polysiloxane B, the structure Polymethylhydrogensiloxane represented by formula (2) (weight average molecular weight: 8400, o = 3, p = 65 in structural formula (2)) at a molar ratio (hydrosilyl group weight/alkenyl group weight) of 1. A silicone mixture R2 adjusted to 0 was prepared, and the following release layer forming coating solution M2 containing the silicone mixture R2, the adhesion imparting agent S1, and the catalyst P1 was prepared. A release film for producing a ceramic green sheet was obtained in the same manner as in Example 1.
(Release layer forming coating liquid M2)
Methyl ethyl ketone 64.3 parts Toluene 34.0 parts Silicone mixture R2 1.5 parts Adhesion imparting agent S1 0.083 parts Catalyst P1 0.1 parts Outlines of the releasing layer forming coating solution and laminated film used at that time are as follows. Table 3 shows. Table 4 shows the results of evaluation of various physical properties of the obtained release film.

(Example 3)
As polysiloxane A, a vinyl-modified silicone resin represented by structural formula (1) (weight average molecular weight: 520000, l = 3700, m = 40, n = 0 in structural formula (1)), and polysiloxane B, structure Polymethylhydrogensiloxane represented by formula (2) (weight average molecular weight: 8400, o = 3, p = 65 in structural formula (2)) at a molar ratio (hydrosilyl group weight/alkenyl group weight) of 3. Example 1, except that a silicone mixture R3 adjusted to be 0 was prepared, and the following release layer-forming coating solution M3 containing the silicone mixture R3, an adhesion imparting agent S1, and a catalyst was prepared. A release film for producing a ceramic green sheet was obtained in the same manner as in .
(Release layer forming coating solution M3)
Methyl ethyl ketone 64.3 parts Toluene 34.0 parts Silicone mixture R3 1.5 parts Adhesion imparting agent S1 0.083 parts Catalyst P1 0.1 parts Outlines of the releasing layer forming coating solution and laminated film used at that time are as follows. Table 3 shows. Table 4 shows the results of evaluation of various physical properties of the obtained release film.

(Example 4)
A release film for producing a ceramic green sheet was obtained in the same manner as in Example 1, except that the coating liquid M1 for forming a release layer was applied so that the coating amount after drying was 0.050 μm. Table 3 shows an overview of the release layer-forming coating solution and the laminated film used at that time. Table 4 shows the results of evaluation of various physical properties of the obtained release film.

(Example 5)
A release film for producing a ceramic green sheet was obtained in the same manner as in Example 1, except that the coating liquid M1 for forming a release layer was applied so that the coating amount after drying was 0.080 μm. Table 3 shows an overview of the release layer-forming coating solution and the laminated film used at that time. Table 4 shows the results of evaluation of various physical properties of the obtained release film.

(Example 6)
Example 1, except that the following release layer-forming coating solution M4 containing the silicone mixture R1, the adhesion imparting agent S2, and the catalyst P1 was applied so that the coating amount after drying was 0.020 μm. A release film for producing a ceramic green sheet was obtained in the same manner as in .
(Release layer forming coating solution M4)
Methyl ethyl ketone 64.3 parts Toluene 34.0 parts Silicone mixture R1 1.5 parts Adhesion imparting agent S2 0.075 parts (manufactured by Shin-Etsu Chemical Co., Ltd., KBM503 (3-methacryloxypropyltrimethoxysilane, solid concentration 100% ))
p-Toluenesulfonic acid 0.008 part Catalyst P1 0.1 part Table 3 shows the summary of the releasing layer-forming coating solution and laminated film used at that time. Table 4 shows the results of evaluation of various physical properties of the obtained release film.

(Example 7)
Example 1, except that the following release layer-forming coating solution M5 containing the silicone mixture R1, the adhesion imparting agent S3, and the catalyst P1 was applied so that the coating amount after drying was 0.020 μm. A release film for producing a ceramic green sheet was obtained in the same manner as in .
(Release layer forming coating liquid M5)
Methyl ethyl ketone 64.3 parts Toluene 34.0 parts Silicone mixture R1 1.5 parts Adhesion agent S3 0.075 parts (manufactured by Shin-Etsu Chemical Co., Ltd., KBM403 (3-glycidoxypropyltrimethoxysilane, solid concentration 100 %))
p-Toluenesulfonic acid 0.008 part Catalyst P1 0.1 part Table 3 shows the summary of the releasing layer-forming coating solution and laminated film used at that time. Table 4 shows the results of evaluation of various physical properties of the obtained release film.

(Example 8)
Example 1, except that the following release layer-forming coating solution M6 containing the silicone mixture R1, the adhesion imparting agent S4, and the catalyst P1 was applied so that the coating amount after drying was 0.020 μm. A release film for producing a ceramic green sheet was obtained in the same manner as in .
(Release layer forming coating solution M6)
Methyl ethyl ketone 64.3 parts Toluene 34.0 parts Silicone mixture R1 1.5 parts Adhesion agent S4 0.075 parts (manufactured by Shin-Etsu Chemical Co., Ltd., KBM1003 (vinyltrimethoxysilane, solid concentration 100%))
p-Toluenesulfonic acid 0.008 part Catalyst P1 0.1 part Table 3 shows the summary of the releasing layer-forming coating solution and laminated film used at that time. Table 4 shows the results of evaluation of various physical properties of the obtained release film.

(Example 9)
In the same manner as in Example 1, except that the release layer forming coating solution M7 having a different content ratio of the adhesion imparting agent S1 was applied so that the coating amount after drying was 0.020 μm. A release film for manufacturing a ceramic green sheet was obtained.
(Release layer forming coating liquid M7)
Methyl ethyl ketone 64.4 parts Toluene 34.0 parts Silicone mixture R1 1.5 parts Adhesion imparting agent S1 0.042 parts Catalyst P1 0.1 parts Outlines of the releasing layer forming coating solution and laminated film used at that time are as follows. Table 3 shows. Table 4 shows the results of evaluation of various physical properties of the obtained release film.

(Example 10)
In the same manner as in Example 1, except that the following release layer forming coating liquid M8 having a different content ratio of the adhesion imparting agent S1 was applied so that the coating amount after drying was 0.020 μm. A release film for manufacturing a ceramic green sheet was obtained.
(Release layer forming coating liquid M8)
Methyl ethyl ketone 64.3 parts Toluene 34.0 parts Silicone mixture R1 1.5 parts Adhesion imparting agent S1 0.125 parts Catalyst P1 0.1 parts The overview of the release layer forming coating liquid and laminated film used at that time is as follows. Table 3 shows. Table 4 shows the results of evaluation of various physical properties of the obtained release film.

(Example 11)
In the same manner as in Example 1, except that the release layer forming coating solution M9 having a different content ratio of the adhesion imparting agent S1 was applied so that the coating amount after drying was 0.020 μm. A release film for manufacturing a ceramic green sheet was obtained.
(Release layer forming coating solution M9)
Methyl ethyl ketone 64.3 parts Toluene 34.0 parts Silicone mixture R1 1.5 parts Adhesion imparting agent S1 0.008 parts Catalyst P1 0.1 parts Outlines of the releasing layer forming coating solution and laminated film used at that time are as follows. Table 3 shows. Table 4 shows the results of evaluation of various physical properties of the obtained release film.

(Example 12)
In the same manner as in Example 1, except that the release layer forming coating solution M10 described below, which has a different content ratio of the adhesion imparting agent S1, was applied so that the coating amount after drying was 0.020 μm. A release film for manufacturing a ceramic green sheet was obtained.
(Release layer forming coating liquid M10)
Methyl ethyl ketone 64.1 parts Toluene 34.0 parts Silicone mixture R1 1.5 parts Adhesion imparting agent S1 0.250 parts Catalyst P1 0.1 parts Outlines of the releasing layer forming coating solution and laminated film used at that time are as follows. Table 3 shows. Table 4 shows the results of evaluation of various physical properties of the obtained release film.

(Example 13)
A release film for producing a ceramic green sheet was obtained in the same manner as in Example 1, except that the coating solution M1 for forming a release layer was applied to the laminated film X2. Table 3 shows an overview of the release layer-forming coating solution and the laminated film used at that time. Table 4 shows the results of evaluation of various physical properties of the obtained release film.

(Example 14)
As polysiloxane A, a vinyl-modified silicone resin represented by structural formula (1) (weight average molecular weight: 18000, l = 110, m = 3, n = 1 in structural formula (1)), and as polysiloxane B, the structure Polymethylhydrogensiloxane represented by formula (2) (weight average molecular weight: 8400, o = 3, p = 65 in structural formula (2)) at a molar ratio (hydrosilyl group weight/alkenyl group weight) of 1. 6 was prepared, and the following release layer-forming coating liquid M11 containing the silicone mixture R4, the adhesion imparting agent S1, and the catalyst P1 was prepared. A release film for producing a ceramic green sheet was obtained in the same manner as in Example 1.
(Release layer forming coating solution M11)
Methyl ethyl ketone 64.3 parts Toluene 34.0 parts Silicone mixture R4 1.5 parts Adhesion imparting agent S1 0.083 parts Catalyst P1 0.1 parts Outlines of the releasing layer forming coating solution and laminated film used at that time are as follows. Table 3 shows. Table 4 shows the results of evaluation of various physical properties of the obtained release film.

(Example 15)
As polysiloxane A, a vinyl-modified silicone resin represented by structural formula (1) (weight average molecular weight: 500000, l = 3460, m = 25, n = 4 in structural formula (1)), and polysiloxane B, structure Polymethylhydrogensiloxane represented by formula (2) (weight average molecular weight: 8400, o = 3, p = 65 in structural formula (2)) at a molar ratio (hydrosilyl group weight/alkenyl group weight) of 3. 5 was prepared, and the following release layer-forming coating solution M12 containing the silicone mixture R5, the adhesion imparting agent S1, and the catalyst P1 was prepared. A release film for producing a ceramic green sheet was obtained in the same manner as in Example 1.
(Release layer forming coating liquid M12)
Methyl ethyl ketone 64.3 parts Toluene 34.0 parts Silicone mixture R5 1.5 parts Adhesion imparting agent S1 0.083 parts Catalyst P1 0.1 parts Outlines of the releasing layer forming coating solution and laminated film used at that time are as follows. Table 3 shows. Table 4 shows the results of evaluation of various physical properties of the obtained release film.

(Comparative example 1)
As polysiloxane A, a vinyl-modified silicone resin represented by structural formula (1) (weight average molecular weight: 480000, l = 3220, m = 13, n = 7 in structural formula (1)), and as polysiloxane B, the structure Polymethylhydrogensiloxane represented by formula (2) (weight average molecular weight: 8400, o = 3, p = 65 in structural formula (2)) at a molar ratio (hydrosilyl group weight/alkenyl group weight) of 4. A silicone mixture R6 adjusted to 0 was prepared, and the following release layer forming coating solution M13 containing the silicone mixture R6, the adhesion imparting agent S1, and the catalyst P1 was prepared. A release film for producing a ceramic green sheet was obtained in the same manner as in Example 1.
(Release layer forming coating solution M13)
Methyl ethyl ketone 64.3 parts Toluene 34.0 parts Silicone mixture R6 1.5 parts Adhesion imparting agent S1 0.083 parts Catalyst P1 0.1 parts Outlines of the release layer forming coating solution and laminated film used at that time are as follows. Table 3 shows. Table 4 shows the results of evaluation of various physical properties of the obtained release film.

(Comparative example 2)
As polysiloxane A, a vinyl-modified silicone resin represented by structural formula (1) (weight average molecular weight: 462000, l = 2820, m = 60, n = 0 in structural formula (1)), and as polysiloxane B, structure Polymethylhydrogensiloxane represented by formula (2) (weight average molecular weight: 8400, o = 3, p = 65 in structural formula (2)) at a molar ratio (hydrosilyl group weight/alkenyl group weight) of 0. Example except that a silicone mixture R7 adjusted to be 8 was prepared, and the following release layer forming coating solution M14 containing the silicone mixture R7, the adhesion imparting agent S1, and the catalyst P1 was prepared. A release film for producing a ceramic green sheet was obtained in the same manner as in Example 1.
(Release layer forming coating liquid M14)
Methyl ethyl ketone 64.3 parts Toluene 34.0 parts Silicone mixture R7 1.5 parts Adhesion imparting agent S1 0.083 parts Catalyst P1 0.1 parts Outlines of the releasing layer forming coating liquid and laminated film used at that time are as follows. Table 3 shows. Table 4 shows the results of evaluation of various physical properties of the obtained release film.

(Comparative Example 3)
Example 1, except that the release layer forming coating solution M15 described below containing the silicone mixture R1, the adhesion imparting agent S4, and the catalyst P1 was applied so that the coating amount after drying was 0.020 μm. A release film for producing a ceramic green sheet was obtained in the same manner as in .
(Release layer forming coating liquid M15)
Methyl ethyl ketone 64.3 parts Toluene 34.0 parts Silicone mixture R1 1.5 parts Adhesion agent S4 0.075 parts (manufactured by Shin-Etsu Chemical Co., Ltd., KBM503 (N-2-(aminoethyl)-3-aminopropyltri Methoxysilane, solids concentration 100%))
p-Toluenesulfonic acid 0.008 part Catalyst P1 0.1 part Table 3 shows the summary of the releasing layer-forming coating solution and laminated film used at that time. Table 4 shows the results of evaluation of various physical properties of the obtained release film.

(Comparative Example 4)
The following coating liquid M16 for forming a release layer containing the silicone mixture R1 and the catalyst P1 and containing no adhesion imparting agent was applied so that the coating amount after drying was 0.020 μm. A release film for producing a ceramic green sheet was obtained in the same manner as in Example 1.
(Release layer forming coating liquid M16)
Methyl ethyl ketone 64.4 parts Toluene 34.0 parts Silicone mixture R1 1.5 parts Catalyst P1 0.1 parts Table 3 shows the overview of the release layer-forming coating solution and laminated film used at that time. Table 4 shows the results of evaluation of various physical properties of the obtained release film.

As the results in Table 4 show, in Examples 1 to 15, the release layer is a layer obtained by curing a curable composition containing polysiloxane A, polysiloxane B, and adhesion imparting agent C, and the formula (a ) and formula (b) are satisfied, a release film is obtained which is excellent in releasability and is less likely to cause transfer/drop-off of the release layer and poor adhesion.

In addition, in Example 11, since the content ratio of the adhesion imparting agent was too small, the effect of improving adhesion over time was small, and it was found that there is a preferable lower limit for the content ratio of the adhesion imparting agent. In Example 12, since the content ratio of the adhesion imparting agent was too large, the peeling force was slightly increased, and it was found that there is a preferred upper limit for the content ratio of the adhesion imparting agent. In Example 14, the weight average molecular weight of polysiloxane A was too small, so that the amount of silicone transferred to PVB was slightly high. In Example 15, since the molar ratio (amount of hydrosilyl groups/amount of alkenyl groups) was slightly large, the ceramic peeling force was slightly high, and it was found that the molar ratio has a preferable upper limit.

On the other hand, in Comparative Example 1, which exceeds the upper limit of formula (a) due to the large molar ratio (amount of hydrosilyl groups/amount of alkenyl groups), the peel strength increased. In Comparative Example 2, in which the molar ratio (amount of hydrosilyl groups/amount of alkenyl groups) is small and therefore is less than the lower limit of formula (a), the result of set-off is poor, and the release layer is formed on the opposite side of the base material to the release layer. Since it is transferred to the surface, there is a concern that the process of processing the ceramic green sheet will be significantly contaminated, and the amount of Si transferred to the PVB sheet has also increased. In Comparative Example 3, in which the upper limit of formula (a) was exceeded as a result of using an undesirable adhesion-imparting agent, the adhesion-imparting agent inhibited curing, resulting in poor set-off and contamination of the ceramic green sheet processing process. There is an extremely high concern that In Comparative Example 4 in which no adhesion-imparting agent was used, the peeling force increased, the adhesion over time decreased, and the amount of Si transferred to the PVB sheet increased slightly.

According to the present invention, by improving the smoothness and releasability of the release layer, it is possible to provide a release film that can form a ceramic green sheet with few defects even in an ultra-thin layer product having a thickness of 1 μm or less. Sheets can be manufactured without fear of defects.

Claims (7)

A release film for producing a ceramic green sheet having a polyester film and a release layer,
The release layer comprises a polysiloxane A having two or more alkenyl groups in the molecule, a polysiloxane B having two or more hydrosilyl groups in the molecule, and an adhesion imparting agent C. A curable composition containing is a hardened layer of matter,
The surface free energy γS (mJ/m ² ) of the surface of the release layer and the hydrogen bond component γSVh (mJ/m ² ) of γS satisfy the following formulas (a) and (b). release film for manufacturing ceramic green sheets.
1.0≤γSVh/γS*100≤6.5 (a)
γS≦30 (b) The ceramic green sheet production according to claim 1, wherein the adhesion imparting agent C is a silane coupling agent having one or more functional groups selected from the group consisting of vinyl groups, epoxy groups, acrylic groups, and methacrylic groups. release film. The release film for producing a ceramic green sheet according to claim 1 or 2, wherein the polysiloxane A has a weight average molecular weight of 300,000 or more and 600,000 or less. Any one of claims 1 to 3, wherein the molar ratio between the amount of hydrosilyl groups possessed by the polysiloxane B and the amount of alkenyl groups possessed by the polysiloxane A in the curable composition satisfies the following formula (c): A release film for producing a ceramic green sheet according to the above item.
1.0≤Si-H/Si-A≤3.8 (c)
(In the formula, Si—H represents the molar amount of hydrosilyl groups, and Si—A represents the molar amount of alkenyl groups.) Any one of claims 1 to 4, wherein the curable composition contains 1% by mass or more and 10% by mass or less of the adhesion imparting agent C with respect to the total amount of the polysiloxane A and the polysiloxane B. A release film for producing a ceramic green sheet according to the above item. The polyester film has a surface layer A that does not substantially contain inorganic particles,
The release layer is laminated on the surface layer A with a thickness of 0.005 μm or more and 0.1 μm or less,
The release film for producing a ceramic green sheet according to any one of claims 1 to 5, wherein the maximum projection height (Sp) on the surface of the release layer is 100 nm or less. A method for producing a ceramic green sheet by molding a ceramic green sheet using the release film for producing a ceramic green sheet according to any one of claims 1 to 6, wherein the molded ceramic green sheet has a thickness of 0.2 μm. A method for producing ceramic green sheets having a thickness of ~1.0 μm.