JP7435557B2 - Release film, ceramic component sheet, and manufacturing method of multilayer ceramic capacitor - Google Patents

Description

The present disclosure relates to a release film, a ceramic component sheet, a method for manufacturing a release film, a method for manufacturing a ceramic component sheet, and a method for manufacturing a multilayer ceramic capacitor.

As a manufacturing method for a multilayer ceramic capacitor, a manufacturing method is known that involves peeling a ceramic green sheet formed on a release film from the release film and laminating it with a plurality of similarly obtained ceramic green sheets ( For example, Patent Document 1). With the demand for smaller multilayer ceramic capacitors, thinner ceramic green sheets are required. Along with this, release films used for forming ceramic green sheets are required to have a smooth surface with sufficiently reduced unevenness and to have excellent release properties.

As a release film with excellent releasability, for example, Patent Document 2 discloses a release film comprising a base film and a polymer layer provided on one surface of the base film, wherein the polymer layer is (meth) It has a layer containing a cured product of an acrylate component, and a film containing a silicone polymer component that covers a part of the surface of the layer opposite to the base film, the silicone polymer component comprising: Release films have been proposed that are polymers of modified silicone oils modified with (meth)acryloyl groups and/or vinyl groups.

JP2003-203822A Japanese Patent Application Publication No. 2010-105384

In order to respond to the recent trend toward further miniaturization of multilayer ceramic capacitors, it is required to form thinner ceramic green sheets and the like. In order to produce such thin ceramic green sheets, it is desirable to further improve the releasability of the release film. However, when the content of the silicone polymer component in the release layer is increased to improve release properties, the silicone polymer component and other components tend to phase separate. There are concerns that it will be difficult to prepare, that the prepared slurry will be difficult to apply to the substrate, and that defects will occur due to aggregation of the silicone polymer, making it difficult to obtain a release layer with sufficient smoothness. .

Therefore, an object of the present disclosure is to provide a release film having excellent releasability and sufficient smoothness, and a method for manufacturing the same. Another object of the present disclosure is to provide a ceramic component sheet that has a release film as described above and can produce a thin green sheet, and a method for producing the same. A further object of the present disclosure is to provide a method of manufacturing a multilayer ceramic capacitor using a release film as described above.

One aspect of the present disclosure is a release film including a base material and a release layer provided on the base material, the release layer comprising a silicone resin having a reactive functional group and other polymerizable components. is a cured product of a composition containing, where X is the peak intensity of silicon on the surface of the release layer opposite to the base material side measured by XPS, and a depth of 4 from the surface of the release layer is When the peak intensity of silicon at .1 nm is Y and the peak intensity of silicon measured when forming a silicone resin layer containing 90% or more of polydimethylsiloxane is Z, X is larger than Y, and Z Provided is a release film in which the ratio of X to Z is 40% or more, and the ratio of Y to Z is 5 to 50%.

Regarding the peak intensity of silicon measured by XPS, the release film has a ratio of X to Z of 40% or more, and Y (peak intensity of silicon at a depth of 4.1 nm from the surface of the release layer). is smaller than the above-mentioned X (peak intensity at the surface of the release layer). Therefore, the resin component derived from the silicone resin having a reactive functional group is present in a larger amount in the surface layer portion of the release layer, resulting in excellent releasability on the surface of the release layer. Furthermore, since the above Y with respect to the above Z (the peak intensity of silicon when forming the layer made of the above silicone resin) is 5 to 50%, at a depth of 4.1 nm from the above surface of the above peeling layer, other Since the resin component derived from the polymerizable component is present in an appropriate amount, aggregation of the resin component derived from the silicone resin is sufficiently reduced, and the release layer has few defects and is sufficiently smooth.

The ratio of the above Y to the above X may be 70% or less.

The release layer may be a cured product of a composition containing a silicone resin having a reactive functional group, a (meth)acrylate having a reactive functional group, and an acrylic silicone graft polymer having a reactive functional group. When the release layer is a cured product formed using the above composition, in the above composition, the acrylic silicone graft polymer having a reactive functional group is combined with a silicone resin and a (meth)acrylate (or a polymer thereof). Because it works to suppress phase separation and aggregation of silicone resin, it is possible to contain more silicone resin than conventional release layers, and the resulting release layer has improved releasability and smoothness. It is possible to achieve both at a higher level.

The content of the acrylic silicone graft polymer may be 10 to 600% by mass based on the total amount of (meth)acrylate. By having the content of the acrylic silicone graft polymer within the above range, phase separation between the silicone resin and (meth)acrylate (or its polymer) and aggregation of the silicone resin can be more fully suppressed, and the peeling of the release layer can be suppressed. It is possible to achieve both a higher level of flexibility and smoothness.

The content of the silicone resin may be 0.5% by mass or more. By setting the content of the silicone resin within the above range, it is possible to increase the content of the silicone resin on the surface of the release layer, thereby further improving the releasability of the release layer.

One aspect of the present disclosure is a ceramic comprising the above-mentioned release film and at least one green sheet selected from the group consisting of a ceramic green sheet and an electrode green sheet provided on the surface of the release layer. Provide parts sheet.

The ceramic component sheet has excellent releasability and has a release film with sufficient smoothness, so the occurrence of pinholes and variations in thickness in the green sheet provided on the release film are sufficiently suppressed. ing. Further, since the ceramic component sheet has a release film with excellent releasability, it is also useful for producing thin green sheets.

One aspect of the present disclosure is a method for producing a release film including a base material and a release layer provided on the base material, the method comprising: a silicone resin having a reactive functional group; a step of coating a slurry containing a composition containing meth)acrylate and an acrylic silicone graft polymer having a reactive functional group and a solvent on the substrate, and reducing the content of the solvent in the slurry. The present invention provides a method for producing a release film, comprising the steps of: providing a photosensitive layer by exposing the photosensitive layer to light to form a release layer made of a cured product of the composition.

The above method for producing a release film uses a composition containing a silicone resin having a reactive functional group, a (meth)acrylate having a reactive functional group, and an acrylic silicone graft polymer having a reactive functional group. The above-mentioned acrylic silicone graft polymer works to suppress phase separation between silicone resin and (meth)acrylate (or (meth)acrylate polymer generated during curing reaction) and aggregation of silicone resin, thereby increasing the amount of silicone resin. It can be included. In addition, in the process of removing the solvent and reducing the solvent content, depending on the specific gravity and surface energy of each component, the (meth)acrylate moves to the substrate side, and the silicone resin moves to the opposite side from the substrate. Moving. When the photosensitive layer is exposed to light in a state where the above-described movement has occurred in the photosensitive layer, the functional groups in each component react and the distribution state of the components in the photosensitive layer is fixed. Due to this effect, the surface of the release layer opposite to the base material side (the surface on which ceramic green sheets, etc. are formed) has excellent releasability and is smooth and smooth with suppressed defects due to aggregation of silicone resin, etc. It is possible to produce a release film with excellent properties.

The method may further include the step of preparing the composition so that the content of the acrylic silicone graft polymer is 10 to 600% by mass based on the total amount of the (meth)acrylate. By preparing a composition such that the content of the acrylic silicone graft polymer is within the above range, phase separation between the silicone resin and (meth)acrylate (or (meth)acrylate polymer generated during the curing reaction) is performed. It is also possible to more fully suppress aggregation of the silicone resin and further reduce the occurrence of defects in the release layer. As a result, it is possible to produce a release film that achieves both high levels of releasability and smoothness of the release layer.

The method may further include the step of preparing the composition so that the content of the silicone resin is 0.5% by mass or more. By preparing a composition so that the content of the silicone resin falls within the above range, a release film with improved release properties of the release layer can be produced.

The reactive functional group may be at least one functional group selected from the group consisting of a (meth)acryloyl group and a vinyl group, and the composition may further contain a photopolymerization initiator.

One aspect of the present disclosure also includes a base material, a release layer provided on the base material, and a ceramic green sheet and an electrode green sheet provided on a surface of the release layer opposite to the base material side. at least one green sheet selected from the group consisting of a silicone resin having a reactive functional group, a (meth)acrylate having a reactive functional group, and a reactive functional group. a step of coating a slurry containing a composition containing an acrylic silicone graft polymer having a functional group and a solvent on the substrate; and a step of reducing the content of the solvent in the slurry to form a photosensitive layer. , forming a release layer made of a cured product of the composition by exposing the photosensitive layer; and forming a release layer made of ceramic powder and an electrode material on the surface of the release layer opposite to the base material side. forming at least one green sheet selected from the group consisting of a ceramic green sheet and an electrode green sheet by applying a paste containing at least one selected from the group and removing the solvent. , provides a method for manufacturing a ceramic component sheet.

The above method for producing a ceramic component sheet prepares and uses a release layer that has excellent releasability and sufficient smoothness, so that the generation of pinholes and thickness variations in the green sheet can be sufficiently suppressed. By using the ceramic component sheet obtained by the above method for manufacturing a ceramic component sheet, the yield of ceramic products such as multilayer ceramic capacitors can be improved.

One aspect of the present disclosure is a method for manufacturing a multilayer ceramic capacitor, which includes the steps of preparing a plurality of the above-described ceramic component sheets, peeling off the release sheet from the ceramic component sheet, and laminating the green sheets to form a plurality of ceramic component sheets. Provided is a method for manufacturing a multilayer ceramic capacitor, which includes the steps of obtaining a laminate having the green sheet, and sintering the laminate to obtain a sintered body.

Since the method for manufacturing a multilayer ceramic capacitor uses the above-described ceramic component sheet, ceramic components can be manufactured with a high yield.

According to the present disclosure, it is possible to provide a release film that has excellent releasability and sufficient smoothness, and a method for producing the same. According to the present disclosure, it is also possible to provide a ceramic component sheet that has a release film as described above and can produce a thin green sheet, and a method for producing the same. According to the present disclosure, it is further possible to provide a method for manufacturing a multilayer ceramic capacitor using a release film as described above.

FIG. 1 is a schematic cross-sectional view showing an example of a release film. FIG. 2 is a schematic cross-sectional view showing an example of a ceramic component sheet. FIG. 3 is a schematic cross-sectional view showing an example of a ceramic component. FIG. 4 is a graph showing the results of depth direction analysis of the delamination layer by XPS measurement in the example. FIG. 5 is a photograph of the appearance of the release films prepared in Example 3 and Comparative Example 6.

Embodiments of the present disclosure will be described below, with reference to the drawings as the case may be. However, the following embodiments are examples for explaining the present disclosure, and are not intended to limit the present disclosure to the following contents. In addition, in the description, the same reference numerals are used for elements having the same structure or the same function, and redundant description will be omitted in some cases. In addition, the positional relationships such as top, bottom, left, and right are based on the positional relationships shown in the drawings unless otherwise specified. Furthermore, the dimensional ratio of each element is not limited to the ratio shown in the drawings.

FIG. 1 is a schematic cross-sectional view showing an example of a release film. The release film 10 has a base film 12 and a release layer 14 provided on the base film 12. The release film 10 can be used, for example, to produce green sheets used in the production of multilayer ceramic capacitors.

As the base film 12, for example, a synthetic resin film or the like is used. Examples of synthetic resins include polyester; polyolefins such as polyethylene and polypropylene; polylactic acid; acrylic resins such as polymethacrylate and polymethyl methacrylate; polyamides such as nylon 6,6; polyvinyl chloride; polyurethane; polystyrene; polycarbonate; polyphenylene sulfide and fluororesins such as polytetrafluoroethylene. The synthetic resin preferably contains polyester, more preferably polyethylene terephthalate. Polyethylene terephthalate film is relatively inexpensive and has excellent mechanical properties and transparency.

The base film 12 may contain filler. By containing the filler in the base film 12, the mechanical strength of the release film 10 can be sufficiently increased. Although the filler content in the base film 12 is not particularly limited, it is preferably within a level that does not deteriorate transparency. Examples of fillers include calcium carbonate, calcium phosphate, titanium oxide, silica, fumed silica, kaolin, talc, alumina, and organic particles.

The thickness s of the base film 12 is preferably 10 to 100 μm, more preferably 20 to 50 μm. By setting the thickness s of the base film 12 to 10 μm or more, the release film 10 has better physical properties such as dimensional stability. By setting the thickness s of the base film 12 to 100 μm or less, the manufacturing cost per unit area of the release film 10 can be further reduced.

The release layer 14 is composed of a cured product of a composition containing a silicone resin having a reactive functional group and other polymerizable components. The release layer 14 has a specific distribution of silicone resin along the depth direction of the release layer 14 . The distribution can be measured by XPS. The distribution can be controlled by adjusting the composition and blending ratio of the composition, adjusting the manufacturing conditions of the manufacturing method described below, and the like.

The distribution measurement of the silicone resin along the depth direction of the release layer 14 by XPS (X-ray photoelectron spectroscopy) is performed by analyzing the composition of the surface of the release layer by XPS measurement, etching the surface of the release layer by sputtering using argon ions. This can be done by using in combination. The release layer is removed from the surface by sputtering, and while the interior is gradually exposed, the composition of the exposed surface is analyzed using XPS. There is a correlation between the etching time by sputtering and the distance (depth) in the thickness direction of the release layer. Therefore, the measurement results by XPS can be graphed as the distribution of silicone resin with respect to the depth from the surface of the release layer. In this specification, the etching rate is measured at 0.05 nm/sec.

The release layer 14 has a depth from the surface of the release layer 14, where X is the peak intensity of silicon on the surface of the release layer 14 opposite to the base material (base film 12) side measured by XPS. When the peak intensity of silicon at 4.1 nm is Y, and the peak intensity of silicon measured when forming a silicone resin layer containing 90% or more of polydimethylsiloxane is Z, X is larger than Y, The ratio of X to Z is 40% or more, and the ratio of Y to Z is 5 to 50%.

The peak intensity X with respect to the peak intensity Z may be, for example, 43% or more, 45% or more, or 50% or more, and may be 90% or less. By having the peak intensity X within the above range, the releasability of the release layer 14 can be further enhanced, and the load required to peel off the green sheet after forming the green sheet on the release layer 14 can be reduced. Can be done. The peak intensity Y with respect to the peak intensity Z may be, for example, 5 to 40%, 5 to 30%, 10 to 30%, or 10 to 25%. When the peak intensity Y is within the above range, the resin component derived from the other polymerizable components moderately coexists with the resin component derived from the silicone resin, and the aggregation of the silicone resin is sufficiently suppressed. The smoothness of the surface can be further improved.

The ratio of the peak intensity Y to the peak intensity X is preferably 70% or less, more preferably 60% or less, and still more preferably 50% or less. By setting the ratio of the peak intensity Y to the peak intensity X within the above range, it is possible to sufficiently reduce the silicone component on the base film 12 side, improve coating film forming properties, and cure Breakage at the interface between the release layer and the base material, which will be obtained later, can be more fully suppressed.

The thickness t of the release layer 14 is preferably 0.5 to 3 μm, more preferably 1 to 2 μm, and still more preferably 1 to 1.5 μm. By setting the thickness t of the release layer 14 to 0.5 μm or more, the influence of unevenness on the surface of the base film 12 can be more fully reduced, and the surface of the release layer 14 opposite to the base film can be more fully reduced. (Peeling surface 14a) can have more sufficient smoothness. By setting the thickness t of the release layer 14 to 3 μm or less, it is possible to prevent the release film 10 from warping due to shrinkage of the photosensitive layer due to the curing reaction during formation of the release layer.

The microroughness Sp of the surface of the release layer 14 opposite to the base film 12 side (release surface 14a) may be 100 nm or less, 50 nm or less, 40 nm or less, 35 nm or less, or 30 nm or less. . By having the microroughness Sp of the release surface 14a within the above range, the occurrence of pinholes etc. can be more fully suppressed in the ceramic green sheet and electrode green sheet formed using the release film 10, and Variations in the thickness of the ceramic green sheet and the electrode green sheet can be sufficiently reduced, and the smoothness can be improved. The microroughness Sp can be measured using Micromap System (optical interference three-dimensional non-contact surface shape measurement system) manufactured by Ryoka System Co., Ltd. in accordance with the method described in JIS B 0601:2013.

The above-mentioned release film 10 can be manufactured, for example, by the following manufacturing method. One embodiment of the method for producing a release film includes a step of applying a slurry containing a composition containing a silicone resin having a reactive functional group and a solvent onto a substrate (coating step); a step of forming a photosensitive layer by reducing the content of the solvent (solvent reduction step); and a step of forming a release layer composed of a cured product of the composition by exposing the photosensitive layer (exposure step). , has.

The coating step in the method for producing a release film is a step of coating a slurry onto a substrate to form a coating film containing the above composition. As a coating method for forming a coating film, for example, a bar coating method, a Meyer bar coating method, a reverse coating method, a gravure coating method, a rod coating method, a die coating method, a spray coating method, etc. can be used.

As the solvent contained in the slurry, a solvent capable of dissolving the silicone resin having a reactive functional group and other components is used. Examples of the solvent include toluene, xylene, methyl ethyl ketone (MEK), isopropyl alcohol (IPA), propylene glycol monomethyl ether (PGME), and propylene glycol monomethyl ether acetate (PEGMA). These solvents may be used alone or in combination of two or more.

The composition containing a silicone resin having a reactive functional group includes a silicone resin having a reactive functional group, a (meth)acrylate having a reactive functional group, and an acrylic silicone graft polymer having a reactive functional group. Good too. The reactive functional group includes at least one functional group selected from the group consisting of a vinyl group and a (meth)acryloyl group. A plurality of reactive functional groups may be the same or different. In this specification, "(meth)acrylate" means acrylate and methacrylate, and "(meth)acryloyl group" indicates an acryloyl group and a methacryloyl group.

The silicone resin having a reactive functional group (hereinafter also referred to as component (A)) may be, for example, a modified silicone oil modified with a reactive functional group. Examples of the modified silicone oil include silicone oil modified with (meth)acrylate at one end, silicone oil modified with (meth)acrylate at both ends, silicone oil modified with side chain (meth)acrylate, silicone oil modified with (meth)acrylate at both ends, Examples include silicone oil modified with vinyl at one end, silicone oil modified with vinyl at both ends, silicone oil modified with vinyl at both ends, and silicone oil modified with vinyl at both ends. These modified silicone oils may be used alone or in combination of two or more.

As the modified silicone oil, for example, one represented by the following general formula (1) or the following general formula (2) may be used.

In the above general formula (1), R ¹ and R ² independently represent a single bond or a divalent hydrocarbon group. m represents an integer of 1 or more. R ¹ and R ² are preferably a polymethylene group having about 1 to 10 carbon atoms or an alkylene group having about 1 to 10 carbon atoms. m is preferably about 10 to 1000.

In the above general formula (2), R ³ and R ⁴ independently represent a single bond or a divalent hydrocarbon group. n represents an integer of 1 or more. R ³ and R ⁴ are preferably a polymethylene group having about 1 to 10 carbon atoms or an alkylene group having about 1 to 10 carbon atoms. Further, n is preferably about 10 to 1000.

The (meth)acrylate having a reactive functional group (hereinafter also referred to as component (B)) preferably has two or more reactive functional groups, even if it has three or more reactive functional groups. good. (Meth)acrylates having a reactive functional group include, for example, alkylene diol di(meth)acrylates, (meth)acrylates having a trimethylolpropane skeleton, (meth)acrylates having a pentaerythritol skeleton, and dipentaerythritol skeletons. Examples include (meth)acrylate. These (meth)acrylates may be used alone or in combination of two or more.

Examples of the alkylene diol di(meth)acrylate include nonanediol di(meth)acrylate, decanediol di(meth)acrylate, and butylpropanediol diacrylate. Examples of the (meth)acrylate having a trimethylolpropane skeleton include trimethylolpropane di(meth)acrylate and trimethylolpropane tri(meth)acrylate. Examples of the (meth)acrylate having a pentaerythritol skeleton include pentaerythritol tetra(meth)acrylate. Examples of the (meth)acrylate having a dipentaerythritol skeleton include dipentaerythritol hexa(meth)acrylate.

Acrylic silicone graft polymers having reactive functional groups (hereinafter also referred to as component (C)) are acrylic polymers that are polymers of monomers containing (meth)acrylic acid and/or (meth)acrylic acid esters. This is a polymer into which silicone macromonomer is introduced. Acrylic silicone graft polymers having reactive functional groups may be used alone or in combination of two or more. The acrylic silicone graft polymer with reactive functionality preferably has one reactive functionality. The silicone that is the graft portion has a polysiloxane structure, preferably a polydimethylsiloxane structure. It is preferable that a plurality of polysiloxane structures are introduced into the acrylic silicone graft polymer having reactive functional groups. The content rate of the polysiloxane structure may be, for example, 3% by mass or more based on the total amount of the acrylic silicone graft polymer.

In this specification, "acrylic silicone graft polymer having a reactive functional group" includes oligomers having a relatively small molecular weight. That is, the "acrylic silicone graft polymer having a reactive functional group" includes an acrylic silicone graft oligomer having a reactive functional group. The weight average molecular weight of the acrylic polymer moiety constituting the main chain of the acrylic silicone graft polymer having a reactive functional group may be, for example, 5,000 to 2,000,000, 30,000 to 1,000,000, or 100,000 to 400,000. It's fine. As used herein, "weight average molecular weight" means a value measured by gel permeation chromatography, and is expressed as a polystyrene equivalent value.

As the acrylic silicone graft polymer having a reactive functional group, a commercially available one may be used, or one synthesized separately may be used. Examples of acrylic silicone graft polymers having reactive functional groups include the KP-500 series manufactured by Shin-Etsu Chemical Co., Ltd., the Cymac series manufactured by Toagosei Co., Ltd. (Cymac is a registered trademark), and the Cymac series manufactured by Taisei Fine Chemical Co., Ltd. 8SS (UV curable silicone acrylic polymer) series, etc. can be used.

Acrylic silicone graft polymers having reactive functional groups can be prepared, for example, by the following preparation method. As an example of the preparation method, for example, a silicone macromonomer is introduced into a polymer (linear acrylic polymer) of monomers such as (meth)acrylic acid and (meth)acrylate through a polymer reaction, and then , a method for preparing an acrylic silicone graft polymer having a reactive functional group by reacting a (meth)acrylate having a glycidyl group with a carboxyl group derived from acrylic acid to introduce a reactive functional group. Can be mentioned.

In addition to the above-mentioned method, methods for preparing acrylic silicone graft polymers having reactive functional groups include using monomers such as (meth)acrylic acid and (meth)acrylate, and monomers having a glycidyl group such as glycidyl (meth)acrylate. A silicone macromonomer is introduced by a polymer reaction into a linear acrylic polymer obtained by copolymerizing the acrylic polymer, and then (meth)acrylic acid, (meth)acrylic acid chloride, (meth)acrylamide, and (meth)acrylate having a hydroxyl group (for example, 2-hydroxyethyl (meth)acrylate, etc.) are reacted to form a reactive functional group (here, (meth)acrylate). A method for preparing an acrylic silicone graft polymer having a reactive functional group by introducing an acrylic group (acryloyl group) may also be used. The above-mentioned method of copolymerizing the monomer having a glycidyl group includes a method of copolymerizing a monomer having a hydroxyl group and then reacting the hydroxyl group with an isocyanate compound having a (meth)acryloyl group, and a method of copolymerizing the monomer having a phenolic hydroxyl group. Alternatively, a method may be used in which a monomer having a thiol group is copolymerized and then a (meth)acrylate having a glycidyl group is reacted with the phenolic hydroxyl group or thiol group.

In addition to the methods described above, acrylic silicone graft polymers having reactive functional groups can be produced by combining polysiloxanes having one vinyl group or (meth)acryloyl group with monomers such as (meth)acrylic acid and (meth)acrylate, and glycidyl ( It can also be prepared by copolymerizing with a monomer having a glycidyl group such as meth)acrylate and introducing a reactive functional group into an acrylic polymer having a silicone graft as described above.

The method may further include the step of preparing the composition so that the content of the component (C) is 10 to 600% by mass based on the total amount of the component (B). The content of component (C) may be, for example, 5 to 400% by mass, 12 to 300% by mass, or 15 to 100% by mass, based on the total amount of component (B). By setting the content of component (C) within the above range, it is possible to increase the content of component (A) in the slurry, and it is possible to achieve both high levels of releasability and smoothness of the release layer 14. can do.

The method may further include the step of preparing the composition so that the content of the component (A) is 0.5% by mass or more. The content of component (A) may be, for example, 0.8% by mass or more, 1.0% by mass or more, or 1.2% by mass or more, based on the total amount of the composition. When the content of component (A) is within the above range, a release film with improved release properties of the release layer can be produced.

It is preferable that components (A) and (B) are selected to have low compatibility with each other. By selecting components that are not easily compatible with each other as components (A) and (B), the content of the solvent is reduced from the coating film in the solvent removal process described later, so that they are compatible within the coating film. Separation may occur. Therefore, in the resulting photosensitive layer, a concentration gradient of the (A) component and the (B) component can be more easily provided in the depth direction. Here, by blending component (C), this concentration gradient can be adjusted. In this specification, "not compatible with each other" and "not compatible with each other" mean that when the respective components are mixed, phase separation occurs or cloudiness occurs, and a homogeneous solution is not obtained. .

A composition containing a silicone resin having a reactive functional group may contain other components in addition to component (A), component (B), and component (C). Examples of other components include a photopolymerization initiator and a filler.

As the photopolymerization initiator, a compound that generates radicals upon irradiation with actinic rays can be used. Examples of photopolymerization initiators include 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, and 2-hydroxy-1-{4-[4- α-hydroxyalkylphenones such as (2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one, and 2-methyl-1-(4-methylthiophenyl)-2- Examples include α-aminoalkylphenones such as morpholinopropan-1-one. As the photopolymerization initiator, for example, IRGACURE 184, IRGACURE 127, IRGACURE 907, IRGACURE 379, DAROCURE 1173 (trade name, manufactured by Ciba Specialty Chemicals Co., Ltd.), etc. can be used.

The solvent reduction step in the method for producing a release film is a step of reducing the content of the solvent to provide a photosensitive layer containing the composition. The solvent reduction step is preferably a step of removing the above solvent to provide a photosensitive layer made of the above composition. The solvent may be removed, for example, by heating and drying at a temperature of 50 to 150° C. for 10 seconds to 10 minutes.

The specific gravity of component (B) contained in the slurry is usually about 0.95 to 1.5, and the specific gravity of component (A) is usually about 0.95 to 1.5. That is, the specific gravity of component (B) and component (A) tends to be approximately the same, or component (A) tends to be slightly lighter. Further, (A) has a lower surface energy than component (B). Here, in the case of a slurry containing multiple types of mutually incompatible components, each component moves so that the energy state becomes lower. In the slurry of this embodiment, as described above, component (A) has a lighter specific gravity and a lower surface energy, so that the solvent is reduced from the coating film provided on the base film 12 in the solvent removal step. In the process, component (A) more easily moves to the surface opposite to the base film 12 side (the surface that becomes the peeling surface 14a).

In the exposure step in the method for producing a release film, the reactive functionalities of component (A), component (B), and component (C) are removed by irradiating the photosensitive layer formed by reducing the content of the solvent with actinic light. This is a step of reacting the groups and curing the composition to form a release layer. The irradiation amount of actinic rays can be adjusted depending on the thickness of the photosensitive layer and the like. The exposure step may be performed under a nitrogen atmosphere. By performing the exposure step in a nitrogen atmosphere, deactivation of radically active species due to oxygen can be suppressed, and insufficient curing of the photosensitive layer can be further suppressed. The actinic light is preferably ultraviolet light. As the ultraviolet light source, for example, a mercury lamp, a metal halide lamp, etc. can be used.

One embodiment of the ceramic component sheet includes a base material, a release layer provided on the base material, and a ceramic green sheet and electrode green provided on the surface of the release layer opposite to the base material side. at least one green sheet selected from the group consisting of sheets. The ceramic component sheet may use the above-described release film 10 as a release film having a base material and a release layer provided on the base material.

FIG. 2 is a schematic cross-sectional view showing an example of a ceramic component sheet. The ceramic component sheet 20 includes a release film 10, a ceramic green sheet 22 on the release surface 14a of the release layer 14, and an electrode green sheet 24 formed on the ceramic green sheet 22.

Examples of the ceramic green sheet 22 include a dielectric green sheet for forming a multilayer ceramic capacitor. The thickness of the ceramic green sheet 22 may be, for example, 0.03 to 5 μm or 0.1 to 1 μm. After being peeled off from the release film 10, the ceramic green sheet 22 is fired to become a dielectric material containing at least one selected from the group consisting of, for example, calcium titanate, strontium titanate, and barium titanate.

After the electrode green sheet 24 is peeled off from the release film 10, it is fired and becomes an electrode containing at least one selected from the group consisting of copper, nickel, and alloys thereof, for example.

The above ceramic component sheet can be manufactured, for example, by the following manufacturing method. One embodiment of the method for producing a ceramic component sheet includes a composition containing a silicone resin having a reactive functional group, a (meth)acrylate having a reactive functional group, and an acrylic silicone graft polymer having a reactive functional group, and a solvent. a step of coating a slurry containing on a substrate (coating step), a step of reducing the content of the solvent in the slurry to provide a photosensitive layer (solvent reduction step), and exposing the photosensitive layer to light. a step (exposure step) of forming a release layer made of a cured product of the composition by applying a material from a group consisting of a ceramic powder and an electrode material to the surface of the release layer opposite to the base material side; forming at least one green sheet selected from the group consisting of ceramic green sheets and electrode green sheets by applying a paste containing at least one selected one and removing the solvent (sheet forming step); , has.

The coating process, solvent reduction process, and exposure process are common to the above-described method for manufacturing the release film 10, and the above description can be applied. In the method for manufacturing a ceramic component sheet, by using the above-described release film 10, the coating step, solvent reduction step, and exposure step may be omitted.

In the sheet forming step, a paste containing ceramic powder (ceramic paste) and a paste containing electrode material (electrode paste) are respectively applied onto the surface 14a of the release film 10 on the side opposite to the base film 12 side.

Ceramic paste contains, for example, a dielectric raw material (ceramic powder) and an organic vehicle. The dielectric raw material can be appropriately selected from various compounds that become composite oxides or oxides by firing, such as carbonates, nitrates, hydroxides, and organometallic compounds. The average particle diameter of the dielectric raw material is preferably 0.4 μm or less, more preferably 0.1 to 3.0 μm. The ceramic paste may further contain a dispersant, a plasticizer, an antistatic agent, a dielectric, a glass frit, an insulator, etc., as necessary.

The electrode paste includes at least one material selected from the group consisting of conductive materials such as various conductive metals and alloys, and materials that become conductive materials after firing with various oxides, organometallic compounds, resinates, etc. and an organic vehicle. Examples of the conductive material include nickel metal, nickel alloy, and mixtures thereof. The electrode paste may further contain a plasticizer. When the electrode paste contains a plasticizer, the wettability of the electrode paste to the release layer can be further improved. Examples of the plasticizer include phthalate esters such as benzylbutyl phthalate (BBP), adipic acid, phosphoric esters, and glycols.

As the organic vehicle contained in the ceramic paste and the electrode paste, a binder resin dissolved in an organic solvent can be used. Examples of the binder resin include ethyl cellulose, acrylic resin, butyral resin, polyvinyl acetal, polyvinyl alcohol, polyolefin, polyurethane, polystyrene, and copolymers thereof. The binder resin preferably includes a butyral resin, specifically a polyvinyl butyral resin. By using butyral resin as the binder resin, the mechanical strength of the ceramic green sheets 22 and the electrode green sheets 24 can be increased. The degree of polymerization of the polyvinyl butyral resin is preferably 1000 to 1700, more preferably 1400 to 1700. Furthermore, when a butyral-based resin is used as the binder resin, by using an alkylene diol di(meth)acrylate monomer as a raw material for the release layer 14, the release properties of the ceramic green sheets 22 and the electrode green sheets 24 are made even more excellent. be able to.

Examples of organic solvents used in the organic vehicle include terpineol, alcohol, butyl carbitol, acetone, toluene, xylene, and benzyl acetate. These organic solvents may be used alone or in combination of two or more. Examples of the alcohol include methanol, ethanol, propanol, and butanol.

The above ceramic paste is applied onto the surface 14a of the release film 10 using, for example, a doctor blade device. Then, the applied ceramic paste is heated and dried in a commercially available drying device at a temperature of 50 to 100° C. for 1 to 20 minutes to form a ceramic green sheet 22. The ceramic green sheet 22 shrinks by 5 to 25% compared to before drying.

Next, an electrode paste is printed on the surface 22a of the formed ceramic green sheet 22 using, for example, a screen printing device so as to form a predetermined pattern. Then, the applied electrode paste is heated and dried in a commercially available drying device at a temperature of, for example, 50 to 100° C. for 1 to 20 minutes to form an electrode green sheet 24. As a result, it is possible to obtain a ceramic component sheet 20 in which the release film 10, the ceramic green sheet 22, and the electrode green sheet 24 are sequentially laminated.

Since this ceramic component sheet 20 is manufactured using the release film 10 having the release layer 14, the green sheet 26 consisting of the ceramic green sheet 22 and the electrode green sheet 24 has sufficiently excellent releasability. The peeling residue can be sufficiently reduced. Therefore, variations in the thickness of the green sheet 26 can be sufficiently reduced, and the occurrence of pinholes can be sufficiently suppressed.

Furthermore, since the occurrence of repelling is sufficiently suppressed when applying electrode paste or ceramic paste to the surface 14a of the release layer 14, the green sheet 26 with few pinholes and thickness variations can be easily formed. Can be done. This makes it possible to manufacture the multilayer ceramic capacitor even more easily.

A method for manufacturing a multilayer ceramic capacitor, which is an embodiment of a method for manufacturing ceramic components, will be described below.

One embodiment of the method for manufacturing a multilayer ceramic capacitor includes a step of preparing a plurality of ceramic component sheets (preparation step), a lamination step of laminating a plurality of green sheets of ceramic component sheets to obtain a laminate, and firing the laminate. The method includes a firing step for obtaining a sintered body, and an electrode forming step for forming terminal electrodes on the sintered body to obtain a multilayer ceramic capacitor.

In the preparation step, a plurality of ceramic component sheets 20 manufactured by the above-described ceramic component sheet manufacturing method are prepared. Next, in the lamination step, the green sheets 26 of the plurality of ceramic component sheets 20 are laminated to obtain a laminate in which the plurality of green sheets 26 are laminated.

An example of the lamination process will be explained in detail. First, the release film 10 of the ceramic component sheet 20 is peeled off to obtain the green sheet 26. The green sheet 26 and the ceramic component sheet 20 are laminated so that the surface 22b of this green sheet 26 and the electrode green sheet 24 of another ceramic component sheet 20 face each other. Thereafter, the release film 10 is peeled off from the laminated ceramic component sheet 20. A laminate can be obtained by repeating these steps and stacking the green sheets 26. That is, in this lamination step, a laminate is formed by repeating the procedure of laminating the ceramic component sheet 20 on the green sheet 26 and then peeling off the release film 10 multiple times.

Another example of the lamination process will be explained. The green sheets 26 are stacked such that the surface 22a of the green sheet 26 and the surface 22b of another green sheet 26 from which the release film 10 has been removed face each other. A laminate can be obtained by repeating these steps and sequentially stacking the green sheets 26. That is, in this lamination process, a laminate is formed by repeating the procedure of laminating the green sheets 26 from which the release film 10 has been peeled off a plurality of times.

The number of green sheets stacked in the laminate is not particularly limited, and may be, for example, from several tens to several hundreds of layers. A thicker exterior green sheet on which no electrode layer is formed may be provided on both end faces of the laminate that are perpendicular to the stacking direction. After forming the laminate, the laminate may be cut to form a green chip.

In the firing step, the laminate (green chip) obtained in the lamination step is fired to obtain a sintered body. The firing conditions are preferably 1100 to 1300° C. in an atmosphere such as a humidified mixed gas of nitrogen and hydrogen. However, the oxygen partial pressure in the atmosphere during firing is preferably 10 ^-2 Pa or less, more preferably 10 ^-2 to 10 ^-8 Pa. Note that before firing, it is preferable to perform a binder removal treatment on the laminate. The binder removal process can be performed under normal conditions. For example, when base metals such as nickel and nickel alloys are used as the conductor material of the internal electrode layer (electrode green sheet 24), it is preferable to carry out the heating at 200 to 600°C.

After firing, heat treatment may be performed to re-oxidize the dielectric layer constituting the sintered body. The holding temperature or maximum temperature in the heat treatment is preferably 1000 to 1100°C. The oxygen partial pressure during the heat treatment is preferably higher than the reducing atmosphere during firing, and more preferably from 10 ⁻² Pa to 1 Pa. It is preferable that the sintered body thus obtained be subjected to end face polishing, for example, by barrel polishing, sandblasting, or the like.

In the electrode forming step, a multilayer ceramic capacitor can be obtained by baking a terminal electrode paste onto the side surface of the sintered body to form a terminal electrode.

In the method for manufacturing a ceramic component of the present embodiment, since the above-described ceramic component sheet is used, it is possible to sufficiently suppress the occurrence of pinholes in the resulting ceramic component, that is, a multilayer ceramic capacitor. Therefore, a multilayer ceramic capacitor can be formed with high yield.

FIG. 3 is a schematic cross-sectional view showing an example of a ceramic component. The multilayer ceramic capacitor 100 shown in FIG. 3 includes an interior portion 40 and a pair of exterior portions 50 that sandwich the interior portion 40 in the stacking direction. The multilayer ceramic capacitor 100 of this embodiment has a terminal electrode 60 on the side surface.

The interior portion 40 includes a plurality of (13 layers in this embodiment) ceramic layers 42 and a plurality (12 layers in this embodiment) of internal electrode layers 44 . Ceramic layers 42 and internal electrode layers 44 are alternately stacked. Internal electrode layer 44 is electrically connected to terminal electrode 60.

The exterior part 50 is formed of a ceramic layer. This ceramic layer is formed from an exterior green sheet, and contains the same components as the ceramic layer 42, for example.

Although several embodiments have been described above, the present disclosure is not limited to the above embodiments.

Hereinafter, the content of the present disclosure will be explained in more detail with reference to Examples and Comparative Examples. However, the present disclosure is not limited to the following examples.

(Example 1)
In a reaction vessel, 0.5 parts by mass of a silicone resin having the following general formula (1) in which m is 10 to 100 and R ¹ and R ² are propyl groups as component (A) and as component (B) were placed in a reaction vessel. 85 parts by mass of trimethylolpropane triacrylate, 15 parts by mass of an acrylic silicone graft polymer having an acryloyl group as component (C), 20 parts by mass of propylene glycol monomethyl ether as a solvent, and methyl ethyl ketone (MEK) and isopropyl alcohol (IPA). ) (a solution in which MEK and IPA were mixed at a volume ratio of 1:1) was weighed out and 400 parts by mass was stirred and mixed to obtain a colorless and transparent solution.

A coating liquid (slurry) was prepared by adding 2.5 parts by mass of 1-hydroxy-cyclohexyl-phenyl-ketone as a photopolymerization initiator to the above solution. The prepared coating solution was applied to a biaxially stretched polyethylene terephthalate (PET) film (base film, thickness: 38 μm) using a bar coater, and the solvent was evaporated by drying with hot air at a heating temperature of 80°C for 30 seconds. A photosensitive layer was formed on the PET film. The formed photosensitive layer was irradiated with ultraviolet rays in a nitrogen atmosphere with an oxygen concentration of 100 ppm to obtain a release film having a release layer with a thickness of 1016 nm. Note that the ultraviolet ray irradiation was performed at an integrated light amount of 250 mJ/cm ² . Further, the thickness of the release layer was measured using a spectrophotometer (manufactured by JASCO Corporation, trade name: V-670).

The release film obtained by the above method was subjected to XPS measurement, appearance, and peelability evaluation of the release layer according to the method shown below. The results are shown in Table 1 below.

<XPS measurement (element distribution measurement of the exfoliation layer using X-ray photoelectron spectroscopy, analysis in the depth direction)>
XPS measurement (depth direction analysis) was performed on the release layer of the obtained release film. More specifically, by using a combination of compositional analysis of the surface of the release layer by XPS measurement and etching of the surface of the release layer by sputtering using argon ions, each surface is etched while gradually exposing the inside of the release layer. Compositional analysis was performed.

Instead of the above solution, a release layer was formed on the PET film in the same manner as in Example 1 using a solution in which polydimethylsiloxane was dissolved in a mixed solvent of toluene, MEK, and IPA, and XPS measurement (depth direction analysis) was performed. In an example using only polydimethylsiloxane, the peak intensity of silicon was 30,000 (average value) without depending on the depth direction.

FIG. 4 is a graph showing the results of depth direction analysis of the delamination layer by XPS measurement. In this graph, the vertical axis shows the peak intensity of silicon atoms (a value converted to a value based on the measured value in the release layer made of polydimethylsiloxane), and the horizontal axis shows the depth from the release layer surface (the etching time). (value converted to depth from the surface of the delamination layer). That is, the graph shows the distribution of silicon atoms along the depth direction of the exfoliation layer. In addition, in FIG. 4, the results of Examples and Reference Examples are shown by solid lines, and the results of Comparative Examples are shown by broken lines.

<Evaluation of microroughness Sp>
The microroughness Sp of the release layer in the obtained release film was determined based on the method described in JIS B 0601:2013 for the surface of the release layer opposite to the base film (the surface that becomes the release surface). The surface shape was determined by measurement using Micromap System (optical interference type three-dimensional non-contact surface shape measurement system) manufactured by Ryoka System Co., Ltd.

<Evaluation of appearance>
The appearance of the release layer in the obtained release film was visually observed and evaluated using the following criteria A to D.
A: No defects were observed in the 20 cm x 20 cm area, and the surface was mirror-like.
B: The number of defects observed in a 20 cm x 20 cm area is 5 or less, and interference fringes are generated around the defects (accompanied by variations in thickness).
C: There are 5 or more defects observed in an area of 20 cm x 20 cm, or it is difficult to count the number of defects and there is no gloss.
D: The number of defects observed in a region of 20 cm x 20 cm is 10 or more, and the diameter of at least one of the observed defects is 1 mm or more.

For reference, FIG. 5 shows photographs of the appearance of the release films prepared in Example 3 and Comparative Example 6. 5(a) shows the appearance of the release film prepared in Example 3, and FIG. 5(b) shows the appearance of the release film prepared in Comparative Example 6. As shown in FIG. 5(a), in the release film prepared in Example 3, no defects were observed on the surface of the release layer when the reflection of fluorescent lamps on the release film was observed, and the surface of the release layer was mirror-like. It was confirmed that. On the other hand, in the release film prepared in Comparative Example 6, as shown in Figure 5(b), the image of the fluorescent lamp reflected on the release film was not clear, and numerous defects were observed on the surface of the release layer. It was confirmed that the appearance was inferior.

<Evaluation of peelability>
The releasability of the release layer in the obtained release film was determined in accordance with the 180° peel test method for "adhesive force test method for peeling the release liner against the adhesive surface of the tape" described in ISO29862:2007 (JIS Z 0237:2009). The measurements were carried out as follows. For the measurement, a peel tester (manufactured by Shimadzu Corporation, product name: Autograph AG-X (load cell SBL-10N, load: 10N)) was used.

First, the obtained release film was placed on a cleaned plate glass so that the base film was in contact with it. Next, the adhesive side of a 1-inch wide adhesive tape (manufactured by Nitto Denko Corporation, product name: 31B) was attached to the release layer of the release film using a rubber roller to prevent air from entering. . After adhesion, the base film side of the release film was attached to a test plate of a release tester. The adhesive tape was bent 180 degrees as a gripping margin and connected upward to a gripping jig connected to a load cell. When one minute had passed since the adhesive tape was adhered to the release film, the average value of the load detected by the load cell was obtained when the adhesive tape was pulled up at a loading rate of 300 mm/min. The obtained average value was converted into the releasability of the release film when a 10 mm wide adhesive tape was used.

(Examples 2-4, Examples 6-7, Example 12, Reference Examples 1-6, Comparative Examples 1-7)
A release film was obtained in the same manner as in Example 1, except that the raw materials and charging ratio (mass ratio) were changed as shown in Table 1. Regarding the obtained release film, the thickness of the release layer, XPS measurement of the release layer, appearance, and peelability were evaluated. The results are shown in Table 1 below.

In Table 1, the following compounds were used as component (A), component (B), and component (C).
(A) Component: Silicone resin having a reactive functional group a1: Dimethylpolysiloxane having acryloyl groups at both ends (compound represented by formula (X))
a2: Polydimethylsiloxane having an acryloyl group in the side chain (manufactured by BYK Chemie Co., Ltd., product name: BYK-3500)
(B) component: (meth)acrylate with reactive functional group b1: trimethylolpropane triacrylate b2: dipentaerythritol hexaacrylate (C) component: acrylic silicone graft polymer with reactive functional group acrylic silicone with acryloyl group graft polymer

According to the present disclosure, it is possible to provide a release film that has excellent releasability and sufficient smoothness, and a method for producing the same. According to the present disclosure, it is also possible to provide a ceramic component sheet that has a release film as described above and can produce a thin green sheet, and a method for producing the same. According to the present disclosure, it is further possible to provide a method for manufacturing a multilayer ceramic capacitor using a release film as described above.

DESCRIPTION OF SYMBOLS 10... Release film, 12... Base film, 14... Release layer, 14a... Surface (release surface), 20... Ceramic component sheet, 22... Ceramic green sheet, 22a... Surface, 24... Electrode green sheet, 26... Green sheet , 40... Interior part, 42... Ceramic layer, 44... Internal electrode layer, 50... Exterior part, 60... Terminal electrode, 100... Multilayer ceramic capacitor.

Claims (8)

A release film comprising a base material and a release layer provided on the base material,
The release layer is a cured product of a composition containing a silicone resin having a reactive functional group and other polymerizable components,
The release layer has a silicon peak intensity at a depth of 4.1 nm from the surface of the release layer, where X is the peak intensity of silicon on the surface of the release layer opposite to the base material side measured by XPS. A release film in which the ratio of Y to X is 34 to 70%, where Y is 34% to 70%. The release film according to claim 1, wherein the ratio of the Y to the X is 68% or less. Claim 1, wherein the release layer is a cured product of a composition containing a silicone resin having a reactive functional group, a (meth)acrylate having a reactive functional group, and an acrylic silicone graft polymer having a reactive functional group. Or the release film according to 2. The release film according to claim 3, wherein the content of the acrylic silicone graft polymer in the composition is 10 to 600% by mass based on the total amount of the (meth)acrylate. The release film according to claim 3 or 4, wherein the content of the silicone resin is 0.5% by mass or more based on the total amount of the composition. The release film according to any one of claims 3 to 5, wherein the silicone resin having a reactive functional group contains a modified silicone oil represented by the following general formula (1) or the following general formula (2).

[In general formula (1), R ¹ and R ² independently represent a single bond or a divalent hydrocarbon group. m represents an integer of 1 or more. ]

[In general formula (2), R ³ and R ⁴ independently represent a single bond or a divalent hydrocarbon group. n represents an integer of 1 or more. ] A release film according to any one of claims 1 to 6,
and at least one green sheet selected from the group consisting of ceramic green sheets and electrode green sheets, provided on the surface of the release layer. A method for manufacturing a multilayer ceramic capacitor, the method comprising:
A step of preparing a plurality of ceramic component sheets according to claim 7;
Peeling off the release film from the ceramic component sheet and laminating the green sheets to obtain a laminate having a plurality of the green sheets;
Sintering the laminate to obtain a sintered body;
A method for manufacturing a multilayer ceramic capacitor, comprising:

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