JP7046053B2 - Release film for forming a green sheet - Google Patents

Description

The present invention relates to a release film for forming a green sheet.

The release film is generally composed of a base material and a release agent layer. The green sheet is produced by dispersing ceramic particles and a binder resin in an organic solvent on such a release film, applying a dissolved ceramic slurry, and drying. Further, the produced green sheet is peeled off from the release film and used for manufacturing a ceramic capacitor.
Further, when a green sheet is manufactured using a release film, there is a problem that pinholes are generated on the surface of the green sheet due to the transfer of unevenness on the surface of the release film to the green sheet. Therefore, the release film is required to have smoothness with less surface irregularities. On the other hand, with the recent miniaturization and high density of ceramic capacitors, further thinning of the green sheet is required. Further, by further thinning the green sheet, the release film is required to have further improvement in smoothness.

However, there is a problem that blocking is more likely to occur as the smoothness of the release film is improved. That is, the release film is generally stored and transported in a rolled state, and when forming a green sheet, the release film is unwound from the roll state and used. Therefore, when the wound release film is unwound, there is a problem that blocking (sticking) between the release agent layer on the front surface of the release film and the base material on the back surface of the release film is likely to occur. As described above, in the release film having excellent smoothness, the ability to prevent blocking (anti-blocking property) is required.
As a technique for improving the anti-blocking property of a release film, for example, Patent Document 1 describes a release film provided with a release layer containing inert fine particles on at least one side of the polyester film. In this release film, the ten-point average roughness (Rz) of the surface of the release layer is 20 to 500 nm.

Japanese Unexamined Patent Publication No. 2004-255704

However, with the release film described in Patent Document 1, a release film having both smoothness and anti-blocking property could not be obtained.

Therefore, an object of the present invention is to provide a release film for forming a green sheet, which has excellent smoothness and sufficient anti-blocking property.

The release film for forming a green sheet according to one aspect of the present invention is a release film for forming a green sheet used for forming a green sheet, and comprises a base material and a release agent layer provided on one side of the base material. The release agent layer is characterized by comprising a cured product of a release agent forming material containing (A) an energy ray-curable compound, (B) a hydrophobic silica sol, and (C) a release-imparting component. Is to be.

In the release film for forming a green sheet according to one aspect of the present invention, the average particle size of the (B) hydrophobic silica sol is preferably 10 nm or more and 100 nm or less.
In the release film for forming a green sheet according to one aspect of the present invention, when the coating film of the (B) hydrophobic silica sol is formed, it is preferable that the contact angle of water with respect to the coating film is 100 ° or more.
In the release film for forming a green sheet according to one aspect of the present invention, the average thickness of the release agent layer is preferably 0.2 μm or more and 2 μm or less.
In the release film for forming a green sheet according to one aspect of the present invention, the arithmetic average roughness Ra of the outer surface of the release agent layer is 8 nm or less, and the maximum protrusion height Rp of the outer surface of the release agent layer is Is preferably 50 nm or less.

According to the present invention, it is possible to provide a release film for forming a green sheet having excellent smoothness and sufficient anti-blocking property.

It is a schematic sectional drawing which shows the release film for forming a green sheet which concerns on embodiment of this invention. It is a schematic diagram for conceptually explaining the segregation state of the hydrophobic silica sol in the release film for forming a green sheet which concerns on embodiment of this invention.

Hereinafter, the present invention will be described by taking an embodiment as an example. The present invention is not limited to the content of the embodiment.

As shown in FIG. 1, the release film 1 for forming a green sheet (hereinafter referred to as “release film 1”) according to the present embodiment has a base material 11 and a release agent layer provided on the first surface 11A of the base material 11. 12 and.

(Base material)
The base material 11 according to the present embodiment has a first surface 11A and a second surface 11B.
The material constituting the base material 11 is not particularly limited, and is, for example, polyester resin (polybutylene terephthalate resin, polyethylene terephthalate resin, polyethylene naphthalate resin, etc.), polyolefin resin (polypropylene resin, polymethylpentene resin, etc.), and Examples thereof include a film made of plastic such as polycarbonate. The base material 11 may be a single-layer film, or may be a multilayer film having two or more layers of the same type or different types. Among these, a polyester film is preferable, and a biaxially stretched polyethylene terephthalate film is more preferable, from the viewpoint that dust and the like are less likely to be generated during processing or use. When the green sheet is manufactured by using the release film 1 manufactured by using the polyester film, it is possible to effectively prevent the ceramic slurry from being poorly coated due to dust or the like.

In addition to the above-mentioned materials, the base material 11 may contain a filler or the like. Fillers include silica, titanium oxide, calcium carbonate, kaolin, aluminum oxide and the like. These may be used alone or in combination of two or more. By including such a filler, the mechanical strength of the base material 11 can be imparted, the slipperiness of the front and back surfaces can be improved, and blocking can be suppressed.

The surface roughness (arithmetic mean roughness R _a1 and R _a2 , and the maximum protrusion height R _p1 and R _p2 ) of the first surface 11A and the second surface 11B of the base material 11 are general-purpose grades on both surfaces. Roughness range may be used, or both surfaces may be in the roughness range of high smoothness grade. Further, one of the first surface 11A and the second surface 11B may have a roughness range of a high smoothness grade, and the other surface may have a roughness range of a general-purpose grade. If the second surface 11B of the base material 11 to which the release agent layer 12 is not applied is in the roughness range of a high smoothness grade, the winding of the release film 1 usually causes blocking, but in the present embodiment The release film 1 is less likely to cause blocking.

In the case of a high smoothness grade, the arithmetic average roughness Ra (Ra ₁ ) of the first surface 11A of the base material 11 is preferably 1 nm or more and 40 nm or less, and more preferably 2 nm or more and 20 nm or less. As a result, as will be described later, on the first surface 11A of the base material 11, the release agent layer 12 which fills the unevenness of the first surface 11A and is smoothed is formed. Therefore, when the arithmetic average roughness Ra ₁ is within the above range, the smoothing action of the outer surface 12A of the release agent layer becomes particularly remarkable.
In the case of a high smoothness grade, the maximum protrusion height Rp (Rp ₁ ) of the first surface 11A of the base material 11 is preferably 10 nm or more and 500 nm or less, and more preferably 15 nm or more and 350 nm or less. As a result, as will be described later, on the first surface 11A of the base material 11, the release agent layer 12 which fills the unevenness of the first surface 11A and is smoothed is formed. Therefore, when the maximum protrusion height Rp ₁ is within the above range, the smoothing action of the outer surface 12A of the release agent layer becomes particularly remarkable.

In the case of a high smoothness grade, the arithmetic average roughness Ra (Ra ₂ ) of the second surface 11B of the base material 11 is preferably 1 nm or more and 40 nm or less, and more preferably 2 nm or more and 20 nm or less. Further, in the case of a highly smooth grade, the maximum protrusion height Rp (Rp ₂ ) of the second surface 11B of the base material 11 is preferably 10 nm or more and 500 nm or less, and more preferably 15 nm or more and 350 nm or less. It is particularly preferably 20 nm or more and 300 nm or less.
By using the highly smooth grade base material in this way, even if the release film 1 and the ceramic green sheet formed on the release film 1 are wound, the back surface side (second) of the release film 1 that comes into contact with the coated surface. Since the surface 11B side) is smooth, the ceramic green sheet is not damaged by being pressed, and the quality of the ceramic capacitor is improved.
In the case of the general-purpose grade, the arithmetic average roughness Ra (Ra ₁ ) of the first surface 11A of the base material 11 is usually 5 nm or more and 80 nm or less, and the maximum protrusion height of the first surface 11A of the base material 11 is high. Rp (Rp ₁ ) is usually 100 nm or more and 700 nm or less. Further, in the case of a general-purpose grade, the arithmetic average roughness Ra (Ra ₂ ) of the second surface 11B of the base material 11 is usually 5 nm or more and 80 nm or less, and the maximum protrusion height of the second surface 11B of the base material 11 is high. Rp (Rp ₂ ) is usually 100 or more and 700 nm or less.

In the present specification, the arithmetic average roughness Ra and the maximum protrusion height Rp of the first surface 11A and the second surface 11B of the base material 11 are the surfaces manufactured by Mitutoyo Co., Ltd. in accordance with JIS B0601-1994. It is a value obtained by measuring with a roughness measuring machine SV3000S4 (touch needle type). In the present specification, unless otherwise specified, the "arithmetic mean roughness and the maximum protrusion height" refer to the values obtained by measuring as described above.

The average film thickness of the base material 11 is not particularly limited, but is preferably 10 μm or more and 300 μm or less, and more preferably 15 μm or more and 200 μm or less. As a result, the flexibility of the release film 1 can be made appropriate, and the resistance to tearing or breaking can be made particularly excellent.

(Release layer)
The release agent layer 12 according to the present embodiment is provided on the first surface 11A of the base material 11. The release agent layer 12 is made of a cured product of a release agent forming material. Since the energy ray-curable compound (A) is used in the present embodiment, the release agent layer 12 is formed by irradiating the material for forming the release agent layer with active energy rays and curing the material. The release agent layer 12 can impart smoothness, release property and anti-blocking property to the release film 1.

The arithmetic average roughness Ra (Ra ₀ ) of the outer surface 12A of the release agent layer 12 is preferably 15 nm or less, and more preferably 8 nm or less. The maximum protrusion height Rp (Rp ₀ ) on the outer surface of the release agent layer 12 is preferably 50 nm or less, and more preferably 45 nm or less. As a result, when the green sheet is formed on the outer surface 12A side of the release agent layer 12, it is possible to more reliably prevent pinholes or partial thickness variations from occurring in the green sheet, and the surface of the green sheet can be prevented. It can be made smoother.
With the release agent layer 12 according to the present embodiment, blocking can be performed even when the outer surface 12A is highly smooth as described above and the second surface 11B of the base material 11 is also highly smooth. It won't wake you up.
The material for forming the release agent layer, which will be described later, has an appropriate fluidity when applied on the first surface 11A of the base material 11. Therefore, by using the material for forming the release agent layer, the unevenness of the first surface 11A of the base material 11 can be easily embedded, and the embedded state can be maintained. As a result, it is possible to prevent the unevenness of the base material 11 from affecting the outer surface 12A side opposite to the base material 11 of the release agent layer 12, and the outer surface 12A of the release agent layer 12 can be smoothed. ..

The average thickness of the release agent layer 12 is preferably 0.2 μm or more and 2 μm or less, and more preferably 0.3 μm or more and 1.5 μm or less. When the average thickness of the release agent layer 12 is at least the above lower limit, the smoothness of the outer surface 12A of the release agent layer 12 can be improved, and pinholes or partial thickness variations can be caused in the green sheet. It can be surely prevented. On the other hand, if the thickness of the release agent layer 12 is not more than the upper limit, it is possible to prevent the release film 1 from being curled due to the curing shrinkage of the release agent layer 12, and the base material in contact with the release film 1 is wound up. It is possible to suppress the occurrence of blocking on the second surface 11B of 11 and the outer surface 12A of the release agent layer 12.

The elastic modulus of the release agent layer 12 is preferably 3.5 GPa or more and 8.0 GPa or less, and more preferably 4.0 GPa or more and 8.0 GPa or less. When the average elastic modulus of the release agent layer 12 is within the above range, the outer surface 12A of the release agent layer 12 is sufficiently hard, and when the release films are in close contact with each other, the hydrophobic silica segregated on the surface sinks. It can be suppressed. Therefore, the effect of imparting anti-blocking property by the hydrophobic silica can be further enhanced.

In the present specification, the elastic modulus of the release agent layer 12 uses a nanoindenter (manufactured by MTS, trade name “NanoIndenter SA4”), the maximum indentation depth of the indenter is 100 nm, and the strain rate is 0.05 sec ^-1 . A nanoindentation test was performed under the conditions of a displacement amplitude of 2 nm and a vibration frequency of 45 Hz, and the film elastic modulus of the release film was measured. In the present specification, unless otherwise specified, the "elastic modulus" refers to a value obtained by measuring as described above.

(Material for forming a release agent)
Here, the material for forming the release agent layer used for forming the release agent layer 12 according to the present embodiment will be described.
The material for forming the release agent layer according to the present embodiment contains (A) an energy ray-curable compound, (B) a hydrophobic silica sol, and (C) a release-imparting component.

(Energy ray curable compound)
The (A) energy ray-curable compound according to the present embodiment is not particularly limited and can be selected from conventionally known compounds. Examples of the energy ray-curable compound (A) include energy ray-curable monomers, oligomers and resins, and compositions containing these.
Specific examples include polyfunctional (meth) acrylate, urethane (meth) acrylate, polyester (meth) acrylate, polyether (meth) acrylate, silicone (meth) acrylate and the like. These may be used alone or in combination of two or more.
Examples of the polyfunctional (meth) acrylate include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, and ethylene glycol di (meth) acrylate. Propylene glycol di (meth) acrylate, hexanediol di (meth) acrylate, trimethylol ethanetri (meth) acrylate, trimethylol propanetri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate , Gglycerol tri (meth) acrylate, triallyl (meth) acrylate and the like. These may be used alone or in combination of two or more. Among these, pentaerythritol tetra (meth) acrylate or dipentaerythritol hexa (meth) acrylate is more preferable because it can impart appropriate hardness to the release agent layer 12.
Further, the polyfunctional (meth) acrylate may be a polyfunctional (meth) acrylate containing a functional group. The functional group used is preferably a hydroxyl group, and the dispersibility of the hydrophobic silica sol of the component (B) in the material for forming the release agent layer and the ubiquity in the formed release agent layer 12 can be optimized. .. Specific examples of the hydroxyl group-containing acrylic compound include pentaerythritol tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and trimethylolpropane di. Examples thereof include (meth) acrylate and pentaerythritol di (meth) acrylate. These may be used alone or in combination of two or more. Among these, it is more preferable to use pentaerythritol tri (meth) acrylate because it can impart appropriate hardness to the release agent layer 12. Further, if the polyfunctional (meth) acrylate has a functional group, the release agent layer 12 can be cured by two systems of energy rays and heating by crosslinking with a crosslinking agent, and the degree of curing is desired. Can be a level.

It is also preferable that the polyfunctional (meth) acrylate contains an EO (ethylene oxide) or PO (propylene oxide) -added polyfunctional (meth) acrylate.
The EO (ethylene oxide) or PO (propylene oxide) -added polyfunctional (meth) acrylate is a compound obtained by esterifying an EO or PO-added polyhydric alcohol with acrylic acid. Specific examples thereof include EO or PO-modified glycerol triacrylate, EO or PO-modified trimethylolpropane acrylate, EO or PO-modified pentaerythritol tetraacrylate, and EO or PO-modified dipentaerythritol hexaacrylate. These may be used alone or in combination of two or more. Among these, EO or PO-modified dipentaerythritol hexaacrylate, EO or PO-modified trimethylolpropane tetraacrylate can be prevented from cracking or cracking in the release agent layer 12 by imparting appropriate flexibility to the release agent layer 12. May be used.

The content of the (A) energy ray-curable compound in terms of solid content (content ratio in the total solid content excluding the solvent) in the material for forming the release agent layer is preferably 50% by mass or more.

(Hydrophobic silica sol)
Examples of the type of (B) hydrophobic silica sol according to the present embodiment include sol of silica fine particles such as an alkoxysilane compound and a chlorosilane compound. (B) The hydrophobicized silica sol can impart antiblocking property to the release agent layer 12.
The alkoxysilane compound is not particularly limited as long as it is a silicon compound having a hydrolyzable alkoxyl group, and examples thereof include a compound represented by the general formula (1).
R ¹ _n Si (OR ² ) _4-n ... (1)
In the above general formula, R ¹ represents a hydrogen atom or a non-hydrolyzable group. Examples of the non-hydrolytable group include an alkyl group, a substituted alkyl group (substituent: halogen atom, epoxy atom, (meth) acryloyloxy group, etc.), an alkenyl group, an aryl group, an aralkyl group and the like. R ² represents a lower alkyl group (an alkyl group having 1 to 10 carbon atoms (preferably 1 to 4 carbon atoms)). n is an integer from 0 to 2, and when R ¹ and OR ² are each plural, the plurality of R ^1s may be the same or different, and the plurality of OR ^2s may be the same or different. ..

Here, examples of the alkoxysilane compound represented by the general formula (1) include tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane, and tetraisobutoxysilane. , Tetra-sec-butoxysilane, tetra-tert-butoxysilane, trimethoxysilane hydride, triethoxysilane hydride, tripropoxysilane hydride, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltriisopropoxysilane , Ethyltrimethoxysilane, ethyltriethoxysilane, propyltriethoxysilane, butyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, γ-acryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, dimethyl Examples thereof include dimethoxysilane, methylphenyldimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, divinyldimethoxysilane, and divinyldiethoxysilane. These may be used alone or in combination of two or more.

In this case, if the compound in which n is 0 or the compound in which n is 1 or 2 and R ¹ is a hydrogen atom is completely hydrolyzed as the alkoxysilane compound, an inorganic silica-based cured product can be obtained and partially hydrolyzed. Then, a polyorganosiloxane-based cured product or a mixed-based cured product of an inorganic silica-based and a polyorganosiloxane-based product can be obtained.
On the other hand, a compound in which n is 1 or 2 and R ¹ is a non-hydrolyzable group has a non-hydrolyzable group, so that a polyorganosiloxane-based cured product can be obtained by partial or complete hydrolysis.
Examples of the chlorosilane compound include ethyldichlorosilane, ethyltrichlorosilane, dimethyldichlorosilane, trichlorosilane, trimethylchlorosilane, dimethyldichlorosilane, and methyltrichlorosilane. These may be used alone or in combination of two or more.

The silica sol is a sol in which silica fine particles are dispersed in water or an organic solvent.
The organic solvent is not particularly limited, and examples thereof include methanol, ethanol, isopropanol, ethylene glycol, n-propyl cellosolve, methyl ethyl ketone, methyl isobutyl ketone, dimethylacetamide, propylene glycol monomethyl ether, cyclohexane, benzene, and toluene. These may be used alone or in combination of two or more. Among these, methyl isobutyl ketone and propylene glycol monomethyl ether are more preferable from the viewpoint of having a relatively high boiling point.

(B) The hydrophobic silica sol is characterized in that it is a hydrophobic silica sol treated with a surface modifier having a part or all of silanol groups on the surface of silica particles having a hydrophobic group.
Here, examples of the surface modifier include a silane coupling agent having both a functional group capable of reacting with a silanol group on the surface of silica particles and a hydrophobic group.
Examples of commercially available products of the (B) hydrophobicized silica sol include SIRPGM15WT% -E26 manufactured by CIK Nanotech.

(B) Hydrophobicization The degree of hydrophobization of the silica sol was determined by applying the silica sol on a PET film, removing the solvent to prepare a silica sol coating film, and measuring the contact angle of water with respect to the coating film.
More specifically, when a coating film of (B) hydrophobic silica sol is formed, the contact angle of water with respect to this coating film is preferably 100 ° or more.
That is, if the contact angle of water with respect to the coating film of the silica sol is 100 ° or more, it can be determined that the surface of the silica sol is hydrophobic.
Here, FIG. 2 shows a schematic diagram for conceptually explaining the segregation state of (B) the hydrophobic silica sol.
When a coating film is formed using the material for forming the release agent layer according to the present embodiment, as shown in FIG. 2, the hydrophobic silica sol P is applied to the outer surface 12A of the release agent layer 12 in the release agent layer 12. It is understood that a large amount is present, and the proportion present in the vicinity of the first surface 11A of the base material 11 and in the release agent layer 12 is low.
Therefore, by adding a small amount of the hydrophobic silica sol, an appropriate surface roughness can be imparted to the surface of the release agent layer 12. Therefore, it is possible to prevent blocking between the second surface 11B of the base material 11 and the release agent layer 12 even when the release films 1 are overlapped with each other for a long time.
That is, it is understood that a release agent layer having excellent smoothness can be formed because a predetermined anti-blocking effect can be exhibited by adding a relatively small amount.
When a coating film of (B) hydrophobic silica sol is formed, the contact angle of water with respect to this coating film is more preferably 100 ° or more and 130 ° or less.
On the other hand, when a coating film of silica sol is formed, the contact angle of water with respect to this coating film becomes a value of less than 100 °, and when the hydrophilicity of the silica sol becomes high, the silica sol segregates on the outer surface 12A of the release agent layer 12. It has been confirmed that it exists in a dispersed state in the entire release agent layer 12 without any problem.
Therefore, it is understood that the release agent layer 12 cannot be imparted with anti-blocking property.
A method of measuring the contact angle of water with respect to the coating film when a coating film of silica sol is formed will be specifically described in Example 1.

(B) The average particle size of the hydrophobic silica sol is preferably 10 nm or more and 100 nm or less. When the average particle size is 10 nm or more, the antiblocking property of the release agent layer 12 can be further improved. On the other hand, when the average particle size is 100 nm or less, the smoothness of the outer surface 12A of the release agent layer 12 can be ensured.
Therefore, the average particle size of the (B) hydrophobic silica sol is more preferably 10 nm or more and 50 nm or less, and further preferably 15 nm or more and 40 nm or less.
The average particle size of (B) hydrophobic silica sol is the particle size (median diameter D50) at an integrated value of 50% in the particle size distribution obtained by using a laser diffraction / scattering type particle size distribution measuring device.

The content of the (B) hydrophobic silica sol is preferably 0.4 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the (A) energy ray-curable compound in terms of solid content. It is more preferably 4 parts by mass or more and 30 parts by mass or less, further preferably 0.4 parts by mass or more and 10 parts by mass or less, and particularly preferably 0.4 parts by mass or more and 3 parts by mass or less. When the content is at least the above lower limit, sufficient antiblocking property can be imparted to the release agent layer 12. On the other hand, when the content is not more than the upper limit, the adhesion between the release agent layer 12 and the base material 11 can be ensured.

(Exfoliation imparting component)
Examples of the (C) peeling-imparting component according to the present embodiment include silicone compounds, fluorine compounds, and long-chain alkyl-modified compounds. These may be used alone or in combination of two or more. In particular, as the (C) exfoliating component, a silicone compound is preferable, and polyorganosiloxane having a linear or branched molecular chain can be mentioned. (C) The release-imparting component can impart the release property of the release agent layer 12. Further, the polyorganosiloxane has at least one selected from the group consisting of a (meth) acryloyl group, a vinyl group, a hydroxyl group, a thiol group, and a maleimide group at at least one of the terminal and side chains of the molecular chain. It is preferable to have a sex functional group. Further, the polyorganosiloxane is more preferably one in which the reactive functional group is bonded to a silicon atom in the molecular chain directly or via a divalent linking group. It suffices to have at least one reactive functional group in one molecule.
Examples of the divalent linking group include an alkylene group, an alkyleneoxy group, an oxy group, an imino group, a carbonyl group and a divalent linking group combining them.
The number of carbon atoms of the divalent linking group is preferably 1 to 30, and more preferably 1 to 10.
Further, the polyorganosiloxane can be used in combination of two or more kinds, if necessary.

The modified polyorganosiloxane substituted with such a reactive functional group is incorporated into the crosslinked structure and fixed when the (A) energy ray-curable compound is cured by irradiation with active energy rays. As a result, it is possible to suppress the transfer and transfer of the polyorganosiloxane, which is a component of the release agent layer 12, to the green sheet formed on the outer surface 12A side of the release agent layer 12.

(C) Examples of the organic group other than the reactive functional group constituting the stripping-imparting component include the same or different monovalent hydrocarbon group having no aliphatic unsaturated bond.
The monovalent hydrocarbon group preferably has 1 to 12 carbon atoms, and more preferably 1 to 10 carbon atoms.
Examples of the monovalent hydrocarbon group include an alkyl group (methyl group, ethyl group, propyl group, etc.), an aryl group (phenyl group, tolyl group, etc.) and the like.
Further, as the monovalent hydrocarbon group, it is preferable that 80 mol% or more of the monovalent hydrocarbon groups are methyl groups. As a result, the peelability of the release agent layer 12 can be made particularly excellent.

The content of the (C) peeling-imparting component is preferably 0.01 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the (A) energy ray-curable compound in terms of solid content. It is more preferably 02 parts by mass or more and 15 parts by mass or less, and particularly preferably 0.05 parts by mass or more and 10 parts by mass or less. When the content is at least the above lower limit, the peelability of the release agent layer 12 can be improved. On the other hand, when the content is not more than the upper limit, it is possible to suppress the repelling of the ceramic slurry when the ceramic slurry is applied to the surface of the release agent layer 12.

(Photopolymerization initiator)
In order to cure the material for forming the release agent layer, the material for forming the release agent layer may contain (D) a photopolymerization initiator. (D) By containing the photopolymerization initiator, the release agent layer 12 can be efficiently formed when the material for forming the release agent layer is irradiated with active energy rays. Here, the photopolymerization initiator refers to a compound that generates radical species by irradiation with active energy rays such as ultraviolet rays.

Examples of the photopolymerization initiator (D) include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-. Phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenylketone, 2-methyl-1- [4- (methylthio) Phenyl] -2-morpholinopropanone-1-one, 4- (2-hydroxyethoxy) phenyl-2- (hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4-diethylaminobenzophenone, dichlorobenzophenone , 2-Methylanthraquinone, 2-ethylanthraquinone, 2-tertiary butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethyl Examples thereof include thioxanthone, benzyldimethylketal, acetphenonedimethylketal, p-dimethylamine benzoic acid ester, and oligo [2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propane]. These may be used alone or in combination of two or more.

When (D) a photopolymerization initiator is used, its content shall be 0.5 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the (A) energy ray-curable compound in terms of solid content. Is more preferable, and it is more preferably 0.2 parts by mass or more and 20 parts by mass or less, and particularly preferably 0.5 parts by mass or more and 15 parts by mass or less. When the content is within the above range, particularly excellent curability can be obtained even if the thickness of the release agent layer 12 is within a range in which curability is difficult to obtain due to oxygen inhibition.

The material for forming the release agent layer according to the present embodiment may contain other components in addition to the component (A), the component (B), the component (C) and the component (D). Other components include, for example, cross-linking agents, antioxidants, UV absorbers, antistatic agents, polymerization accelerators, polymerization inhibitors, infrared absorbers, plasticizers and the like. As the cross-linking agent, when a hydroxyl group is used as the functional group of the component (A), a polyvalent isocyanate compound, a polyvalent epoxy compound, a polyvalent aziridine compound, a polyvalent metal chelate compound and the like can be used.
When other components are used, the content thereof is preferably 0.01 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the (A) energy ray-curable compound in terms of solid content, and is 0. It is more preferably 0.02 parts by mass or more and 3 parts by mass or less, and particularly preferably 0.05 parts by mass or more and 2 parts by mass or less.

The material for forming a release agent layer according to the present embodiment can be produced by mixing and dispersing the component (A1) and the component (B). When producing the material for forming the release agent layer, a solvent may be added if necessary.
Examples of the solvent according to the present embodiment include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, pentyl alcohol, ethyl cellosolve, benzene, toluene, xylene, ethylbenzene, cyclohexane and ethyl. Included are cyclohexane, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, tetrahydrofuran, propylene glycol monomethyl ether, water and the like. These may be used alone or in combination of two or more.

(Manufacturing method of release film)
Next, a method for producing the release film 1 of the present embodiment described above will be described.
The release film 1 of the present embodiment has a base material preparation step of preparing the base material 11, a coating layer forming step of forming a coating layer by applying and drying a material for forming a release agent layer, and a coating layer. It can be produced by a method including a release agent layer forming step of forming a release agent layer 12 by irradiating with active energy rays and curing.

In the base material preparation step, the base material 11 is prepared.
The first surface 11A of the base material 11 can be surface-treated. As a result, the adhesion between the base material 11 and the release agent layer 12 provided on the first surface 11A side of the base material 11 can be made particularly excellent.

Examples of the surface treatment include corona discharge treatment, plasma discharge treatment, chromium oxidation treatment (wet), flame treatment, hot air treatment, ozone, and ultraviolet irradiation treatment. These surface treatments are appropriately selected depending on the type of the base material 11, but in general, the corona discharge treatment is preferably used from the viewpoint of effectiveness and operability.

In the coating layer forming step, the above-mentioned material for forming the release agent layer is applied onto the first surface 11A of the base material 11 and dried. As a result, a coating layer is obtained.
By using the above-mentioned material for forming the release agent layer, the unevenness of the first surface 11A of the base material 11 can be filled. As a result, the outer surface 12A of the release agent layer 12 can be smoothed.

Examples of the method of applying the material for forming the release agent layer include a gravure coating method, a bar coating method, a spray coating method, a spin coating method, an air knife coating method, a roll coating method, a blade coating method, a gate roll coating method, and a method. The die coat method and the like can be mentioned.
The method for drying the material for forming the release agent layer is not particularly limited, and examples thereof include a method of drying in a hot air drying furnace or the like.

The drying conditions are not particularly limited, but the drying temperature is preferably 50 ° C. or higher and 130 ° C. or lower, and the drying time is preferably 5 seconds or longer and 1 minute or lower. This makes it possible to prevent unintentional deterioration of the coated layer and to form the coated layer particularly efficiently. As a result, the productivity of the finally obtained release film 1 can be improved. Further, when the drying temperature is within the above range, when the material for forming the release agent layer contains a solvent or the like, it is possible to prevent the coating layer from being warped or cracked due to evaporation of the solvent or the like during drying.

In the release agent layer forming step, the release agent layer 12 is formed by irradiating the coating layer obtained in the coating layer forming step with active energy rays and curing the coating layer.
In this step, in the coating layer forming step, the coating layer in which the unevenness of the first surface 11A of the base material 11 is accurately embedded is cured while maintaining the smoothness of the outer surface 12A thereof. As a result, the release agent layer 12 having a sufficiently smooth outer surface 12A can be obtained. Further, when the material for forming the release agent layer contains the above-mentioned constituent components, the release agent layer 12 having appropriate conductivity can be obtained.

Examples of the active energy beam include electromagnetic waves (infrared rays, visible rays, ultraviolet rays and X-rays, etc.) and particle beams (electron beams, ion beams, neutron beams, α-rays, etc.) and the like. Among these, it is preferable to use ultraviolet rays or visible light, and it is more preferable to use ultraviolet rays. This makes it easier and more reliable to form the release agent layer 12.

When ultraviolet rays are used as the active energy rays, the coating layer can be uniformly cured while sufficiently shortening the curing time for curing the coating layer. Further, the means for irradiating the active energy rays is not particularly limited, and various general means can be used. For example, as the light source, a light source lamp such as a pressure mercury lamp, a metal halide lamp, and an excimer lamp can be used.

When irradiating with active energy rays (ultraviolet rays), the irradiation amount of the active energy rays is preferably 30 mJ / cm ² or more and 400 mJ / cm ² or less, and 50 mJ / cm ² or more and 300 m J / cm. It is more preferably ² or less. Further, it is preferable that the illuminance of the active energy ray is 0.1 W / cm ² or more and 4.0 W / cm ² or less. When the irradiation amount and illuminance of ultraviolet rays are within the above ranges, the coating layer can be cured more uniformly and reliably.

(How to use the release film)
Next, a method of using the release film 1 of the present embodiment described above will be described.
A ceramic capacitor can be manufactured by using the release film 1 of the present embodiment. As a method for manufacturing a ceramic capacitor, for example, a ceramic powder dispersion slurry is applied to the surface of the release agent layer 12 of the release film 1 and dried to form a green sheet, and then the green sheet peeled from the release film 1 is laminated. Then, a method of forming an electrode on a ceramic sheet obtained by firing can be mentioned. Since the release film 1 of the present embodiment is less likely to cause blocking, both the outer surface 12A of the release agent layer 12 and the second surface 11B of the base material 11 can be made highly smooth. As a result, if the ceramic capacitor is formed from the green sheet formed by using the release film 1 of the present embodiment, it is possible to obtain a highly reliable ceramic capacitor in which the occurrence of defects due to a short circuit is prevented.

(Action and effect of the embodiment)
According to this embodiment, the following effects can be obtained.
(1) The material for forming the release agent layer containing the (A) energy ray-curable compound can easily embed the unevenness of the first surface 11A of the base material 11 and can maintain the embedded state. can. As a result, it is possible to prevent the unevenness of the base material 11 from affecting the outer surface 12A side opposite to the base material 11 of the release agent layer 12, and the outer surface 12A of the release agent layer 12 can be smoothed. ..
(2) According to (B) the hydrophobic silica sol, sufficient anti-blocking property can be imparted to the release agent layer 12 even with a small content. And even if (B) a hydrophobic silica sol is used, the smoothness of the outer surface 12A of the release agent layer 12 can be maintained. Further, the release-imparting component (C) can also impart releaseability to the release agent layer 12.

More specific examples of the release film for forming a green sheet according to the present embodiment include, for example, the following release film for forming a green sheet, but the present invention is not limited to such an example. ..
As an example of the release film for forming a green sheet according to the present embodiment, a substrate and a release agent layer provided on one side of the substrate are provided, and the release agent layer is used as (A) an energy ray-curable compound. A release film for forming a green sheet, which comprises a cured product of a release agent-forming material containing (B) a hydrophobic silica sol and (C) a silicone compound as a release-imparting component. Be done.
As an example of the release film for forming a green sheet according to the present embodiment, a substrate and a release agent layer provided on one side of the substrate are provided, and the release agent layer is used as (A) an energy ray-curable compound. Consists of a cured product of a release agent forming material containing (B) a hydrophobic silica sol, (C) a silicone compound as a release-imparting component, and (D) a photopolymerization initiator. , A release film for forming a green sheet.

[Modification of Embodiment]
The present invention is not limited to the above-described embodiment, and modifications, improvements, and the like to the extent that the object of the present invention can be achieved are included in the present invention.
For example, in the above-described embodiment, the base material 11 has been described as having a single-layer structure, but the substrate 11 is not limited thereto. The base material 11 may have a multilayer structure of two or more layers of the same type or different types. Further, the release agent layer 12 has also been described as having a single layer structure, but the present invention is not limited thereto. The release agent layer 12 may also have a multi-layered structure of two or more layers of the same type or different types.
Further, for example, in the above-described embodiment, the release film for forming a green sheet in which the release agent layer 12 is provided on the first surface 11A of the base material 11 has been described, but the present invention is not limited thereto. The release agent layer 12 may be provided on the second surface 11B side of the base material 11.

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these examples. The materials used in Examples and Comparative Examples are shown below.
((A) component)
Energy ray curable compound: Pentaerythritol triacrylate, trade name "NK ester A-TMM-3L", manufactured by Shin Nakamura Chemical Industry Co., Ltd., solid content 100% by mass
((B) component)
Silica sol A: Hydrophobicized silica sol, average particle diameter 30 nm, trade name "SIRPGM15WT% -E26", CIK Nanotech silica sol B: Hydrophobicized silica sol, average particle diameter 30 nm, trade name "SIRMIBK15WT% -E83", CIK Nanotech (Other ingredients)
Silica sol C: Silica sol, average particle diameter 100 nm, trade name "SIRMIBK15WT% -K18", CIK Nanotech silica sol D: silica sol, average particle diameter 30 nm, trade name "OSCAL-1632", JGC Catalysts and Chemicals, Inc. silica sol E: silica sol , Average particle diameter 15 nm, trade name "MIBK-ST", Nissan Chemical Industry Co., Ltd. silica sol F: Silica sol average particle diameter 100 nm, trade name "SIRMIBK-E65", manufactured by CIK Nanotech Co., Ltd. ((C) component)
Detachable ingredient: Product name "SH-28", manufactured by Toray Dow Corning ((D) ingredient)
Photopolymerization Initiator: Trade Name "Irgacure 184", manufactured by BASF

[Example 1]
First, a polyethylene terephthalate film as a base material (trade name "Lumilar U48", manufactured by Toray Industries, Inc., thickness: 38 μm, arithmetic average roughness Ra (Ra ₁ ) of the first surface: 2 nm, maximum protrusion of the first surface. Height Rp (Rp ₁ ): 15 nm, arithmetic mean roughness Ra (Ra ₂ ) of the second surface: 2 nm, maximum protrusion height Rp (Rp ₂ ) of the second surface: 15 nm) were prepared.
Next, 100 parts by mass of the energy ray-curable compound, 0.4 parts by mass of silica sol A, 5 parts by mass of the peeling-imparting component, and 5 parts by mass of the photopolymerization initiator were mixed and diluted with propylene glycol monomethyl ether. , A material for forming a release agent layer having a solid content of 15% by mass was obtained.
Next, the obtained material for forming the release agent layer was applied on the first surface of the base material with a Meyer bar, dried at 70 ° C. for 1 minute, and then irradiated with ultraviolet rays using a high-pressure mercury lamp (integration). The amount of light was 300 mJ / cm ² ) to form a release agent layer (thickness: 1 μm), and a release film for forming a green sheet was obtained.

[Examples 2 to 7 and Comparative Examples 1 to 5]
A material for forming a release agent layer was obtained in the same manner as in Example 1 except that each material was blended according to the composition shown in Table 1.
Further, a release film for forming a green sheet was produced in the same manner as in Example 1 except that the obtained material for forming a release agent layer was used.

[Evaluation of silica sol and release film]
The evaluation of the silica sol (contact angle of the silica sol) and the evaluation of the release film (anti-blocking property, surface roughness of the release agent layer, and elastic modulus of the release agent layer) were performed by the following methods. The results obtained are shown in Table 1.
(1) Contact angle of silica sol Using the silica sol used in Examples and Comparative Examples, a silica sol coating film was formed on a flat glass substrate. Then, when the glass substrate was allowed to stand still and the inclination of the glass substrate was set to 0 degrees, 2 μL of water droplets were dropped, and when the droplets were stationary, the water contact angle was determined by Young's formula.
(2) Anti-blocking property A release film is cut into a size of 100 mm × 100 mm, and two or more sheets of the same release film are laminated. A load was applied to the film so as to be 10 kg / m ² , and after 5 days, the laminated release films were visually confirmed to have blocking under a fluorescent lamp. Then, the anti-blocking property was evaluated according to the following criteria.
A: There is no sticking between the film surfaces.
B: The film surfaces are stuck to each other.

(3) Surface Roughness of Release Agent Layer The surface roughness of the release agent layer of the release film (arithmetic mean roughness Ra ₀ and maximum protrusion height Rp ₀ , unit: nm) is determined by the optical interferometry surface roughness manufactured by Veeco. Measurement was performed using a meter "WYKO-1100" in PSI mode under the condition of a lens magnification of 50 times.
(4) Elastic modulus of the release agent layer Using a nano indenter (manufactured by MTS, trade name "Nano Indenter SA4"), the maximum indentation depth of the indenter is 100 nm, the strain rate is 0.05 sec ^-1 , the displacement amplitude is 2 nm, and the vibration frequency. A nanoindentation test was performed under the condition of 45 Hz, and the film elastic modulus of the release film was measured.

As is clear from the results shown in Table 1, when the release agent forming material containing the hydrophobic silica sol is used (Examples 1 to 7), both the release agent layer and the second surface of the base material are both. It was confirmed that a release film for forming a green sheet having sufficient anti-blocking property can be obtained even with high smoothness.

The release film for forming a green sheet of the present invention can be suitably used as a technique for molding a ceramic green sheet.

1 ... Release film, 11 ... Base material, 12 ... Release agent layer, 12A ... Outer surface of the release agent layer.

Claims (4)

A release film for forming a green sheet used for forming a green sheet.
A base material and a release agent layer provided on one side of the base material are provided.
The release agent layer is composed of a cured product of a release agent forming material containing (A) an energy ray-curable compound, (B) a hydrophobic silica sol, and (C) a release-imparting component .
When the coating film of the (B) hydrophobic silica sol is formed, the contact angle of water with respect to the coating film is 100 ° or more.
The arithmetic average roughness Ra of the outer surface of the release agent layer is 8 nm or less, and the maximum protrusion height Rp of the outer surface of the release agent layer is 50 nm or less.
A release film for forming a green sheet. In the release film for forming a green sheet according to claim 1,
A release film for forming a green sheet, wherein the average particle size of the (B) hydrophobic silica sol is 10 nm or more and 100 nm or less. In the release film for forming a green sheet according to claim 1 or 2 .
A release film for forming a green sheet, wherein the average thickness of the release agent layer is 0.2 μm or more and 2 μm or less. The release film for forming a green sheet according to any one of claims 1 to 3.
The (C) peeling-imparting component is a polyorganosiloxane having a linear or branched molecular chain, and the polyorganosiloxane has a (meth) acryloyl group at at least one of the terminal and side chains of the molecular chain. Has a reactive functional group having at least one selected from the group consisting of a vinyl group, a hydroxyl group, a thiol group, and a maleimide group.
A release film for forming a green sheet.

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