JP2014177093A - Release film for production of green sheet and method of producing release film for production of green sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a release film for production of green sheet which prevents occurrence of pinholes in the surface of a green sheet and enables production of a green sheet with high reliability.SOLUTION: A release film for production of a green sheet is used in production of a green sheet and includes a substrate having a first surface and a second surface, a smoothing layer formed on the first surface and a release agent layer formed on the surface of the smoothing layer opposite to the substrate. The smoothing layer is formed by heating a composition for formation of the smoothing layer containing a heat curable compound of an average molecular weight of 950 or smaller to harden the heat curable compound. The outer surface of the release agent layer has an arithmetic average roughness Raof 8 nm and a maximum protrusion height Rpof 50 nm or smaller.

Description

  The present invention relates to a release film for producing a green sheet and a method for producing a release film for producing a green sheet.

  In the production of ceramic capacitors, a release film for producing a green sheet is used to form a green sheet.

  The release film for producing a green sheet is generally composed of a base material and a release agent layer. The green sheet is manufactured by applying and drying a ceramic slurry in which ceramic particles and a binder resin are dispersed and dissolved in an organic solvent on such a release film for manufacturing a green sheet. Moreover, the manufactured green sheet peels from the peeling film for green sheet manufacture, and is used for manufacture of a ceramic capacitor.

  In the production of a green sheet using a conventional release film for producing a green sheet, problems such as the occurrence of pinholes on the surface of the green sheet due to the surface irregularities of the release film for producing a green sheet being transferred to the green sheet was there. As a result, the ceramic capacitor manufactured by laminating such green sheets has a problem that a malfunction due to a short circuit occurs. In order to solve such a problem, the surface (cast surface) of the release film for producing a green sheet is required to have very high smoothness.

  Therefore, as a method for producing a release film for producing a green sheet with a smooth surface, it is formed by applying a thermosetting resin liquid to one surface of a substrate sheet with fine irregularities on the surface, and heating and curing it. There has been proposed a release film in which a thermosetting resin layer is provided and a release agent is further applied to form a release agent layer (see, for example, Patent Document 1).

  In addition, with the recent reduction in size and density of ceramic capacitors, further reduction in the thickness of green sheets has been demanded. However, in the conventional release film for producing a green sheet, if a thin green sheet is to be produced, a pinhole or the like is generated on the surface of the green sheet, and it is difficult to obtain a reliable green sheet.

JP 2007-069360 A

  An object of the present invention is to provide a release film for producing a green sheet that can prevent the occurrence of pinholes and partial thickness variations on the surface of the green sheet and can produce a highly reliable green sheet. It is another object of the present invention to provide a production method for producing a release film for producing a green sheet capable of preventing the occurrence of pinholes and partial thickness variations on the surface of the green sheet.

Such an object is achieved by the present inventions (1) to (7) below.
(1) A release film for producing a green sheet used for producing a green sheet,
A substrate having a first surface and a second surface;
A smoothing layer provided on the first surface side of the substrate;
A release agent layer provided on the surface side opposite to the base material of the smoothing layer,
The smoothing layer is formed by heating and curing a composition for forming a smoothing layer containing a thermosetting compound having a mass average molecular weight of 950 or less,
The arithmetic average roughness Ra ₁ of the outer surface of the release agent layer is 8 nm or less, and the maximum protrusion height Rp ₁ of the outer surface of the release agent layer is 50 nm or less. Release film.

(2) the arithmetic mean roughness Ra ₂ of the first surface is 10 to 200 nm, and green according to the maximum projection height Rp ₂ of the first surface is 80～1000Nm (1) Release film for sheet production.

  (3) The release film for producing a green sheet according to (1) or (2), wherein an average film thickness of the smoothing layer is 0.2 to 10 μm.

  (4) The release film for producing a green sheet according to any one of (1) to (3), wherein the thermosetting compound is a bisphenol type epoxy compound.

(5) The arithmetic average roughness of the substrate opposite to the surface of the smoothing layer Ra ₄ is a 8nm or less, and the maximum protrusion height of the substrate opposite to the surface of the smoothing layer Rp ₄ is The release film for producing a green sheet according to any one of the above (1) to (4), which is 50 nm or less.

(6) the second arithmetic mean roughness Ra ₃ of the surface is 10 to 200 nm, and said second maximum projection height Rp ₃ the surfaces to be above (1) to 80～1000Nm (5) A release film for producing a green sheet according to any one of the above.

(7) A method for producing a release film for producing a green sheet according to any one of (1) to (6) above,
A base material preparing step of preparing the base material having the first surface and the second surface;
A coating layer forming step of forming a coating layer by coating the smoothing layer forming composition containing the thermosetting compound having a mass average molecular weight of 950 or less on the first surface side of the substrate;
A smoothing layer forming step of forming the smoothing layer by heating and curing the coating layer;
A release agent layer forming step of forming the release agent layer on the surface side of the smoothing layer opposite to the substrate;
The arithmetic average roughness Ra ₁ of the outer surface of the release agent layer is 8 nm or less, and the maximum protrusion height Rp ₁ of the outer surface of the release agent layer is 50 nm or less. A method for producing a release film.

  According to the present invention, there is provided a release film for producing a green sheet that can prevent the occurrence of pinholes and partial thickness variations on the surface of the green sheet and can produce a highly reliable green sheet. can do. In particular, even when a substrate having a relatively large surface roughness is used as a substrate constituting the release film for producing a green sheet, a release film for producing a green sheet having excellent outer surface smoothness is provided. be able to. If this release film for producing a green sheet is used, pinholes, partial thickness variations and the like can be prevented from occurring on the surface of the green sheet. As a result, when a capacitor is produced by laminating green sheets, it is possible to prevent a problem due to a short circuit from occurring. Moreover, according to this invention, the peeling film for green sheet manufacture which can manufacture the green sheet excellent in the smoothness of the surface can be manufactured easily and reliably.

It is a cross-sectional view of a release film for producing a green sheet of the present invention.

Hereinafter, the present invention will be described in detail based on preferred embodiments.
<Peeling film for manufacturing green sheets>
The release film for producing a green sheet of the present invention is used for producing a green sheet. And the manufactured green sheet is used for manufacture of a ceramic capacitor etc., for example.

  FIG. 1 is a cross-sectional view of a release film for producing a green sheet of the present invention. In the following description, the upper side in FIG. 1 is referred to as “upper” and the lower side is referred to as “lower”.

  As shown in FIG. 1, the release film 1 for producing a green sheet includes a base material 11 having a first surface 111 and a second surface 112, and a smooth surface provided on the first surface 111 of the base material 11. And a release agent layer 13 provided on the side of the surface 121 opposite to the base material of the smoothing layer 12 (hereinafter also referred to as “third surface 121”). That is, as shown in FIG. 1, the release film 1 for producing a green sheet has a three-layer structure in which a base material 11, a smoothing layer 12, and a release agent layer 13 are laminated so as to be joined to each other in this order. It is.

  In addition, in this specification, when manufacturing a green sheet using the release film for manufacturing a green sheet, the green sheet is applied with, for example, a ceramic slurry dissolved on the outer surface 131 of the release agent layer 13. Formed with.

In the present invention, the release film for producing a green sheet has a smoothing layer between the substrate and the release agent layer. And the peeling film for green sheet manufacture of this invention is formed when a smoothing layer is heated and hardened | cured the composition for smoothing layer formation containing the thermosetting compound whose predetermined | prescribed mass mean molecular weight is 950 or less. The arithmetic average roughness Ra ₁ of the outer surface of the release agent layer is 8 nm or less, and the maximum protrusion height Rp ₁ of the outer surface of the release agent layer is 50 nm or less. Yes.

  By having such characteristics, it is possible to obtain a release film for producing a green sheet that is excellent in smoothness of the outer surface of the release agent layer and excellent in peelability. If a green sheet is manufactured using this green sheet manufacturing release film, pinholes and partial thickness variations are prevented from occurring on the surface of the green sheet, and a highly reliable green sheet is manufactured. Can do. As a result, when a capacitor is produced by laminating green sheets, it is possible to prevent a problem due to a short circuit from occurring.

  By the way, some films used as a substrate have various surface roughnesses, and the cheaper the film, the more likely the surface roughness is relatively rough. Even when a release film for producing a green sheet is formed using a substrate having such a relatively rough surface, a smoothing layer having the above-described characteristics can be provided on the surface of the substrate. The unevenness of the substrate can be embedded accurately. As a result, the surface of the smoothing layer opposite to the substrate can be smoothed. Thereby, it is possible to prevent the unevenness of the base material from affecting the outer surface of the release agent layer formed on the smoothing layer, and the green sheet having excellent smoothness of the outer surface of the release agent layer A release film for production can be obtained.

  Hereinafter, each layer which comprises the peeling film 1 for green sheet manufacture which concerns on this embodiment is demonstrated one by one.

<Substrate 11>
The base material 11 has a function of imparting physical strength such as rigidity and flexibility to the release film 1 for producing a green sheet (hereinafter sometimes simply referred to as “release film 1”).

As shown in FIG. 1, the base material 11 has a first surface 111 and a second surface 112.
The material constituting the substrate 11 is not particularly limited, and examples thereof include polyester resins such as polybutylene terephthalate resin, polyethylene terephthalate resin and polyethylene naphthalate resin, polyolefin resins such as polypropylene resin and polymethylpentene resin, and polycarbonate. Examples thereof include a film made of plastic, and it may be a single layer film or a multilayer film of two or more layers of the same kind or different kinds. Among these, a polyester film is preferable, a polyethylene terephthalate film is more preferable, and a biaxially stretched polyethylene terephthalate film is more preferable. In particular, the polyester film is less prone to dust and the like during its processing and use. Therefore, for example, when a green sheet is manufactured using the release film 1 manufactured using a polyester resin, it is possible to effectively prevent a ceramic slurry coating failure due to dust or the like. As a result, a green sheet with fewer pinholes and the like can be manufactured.

  In addition to the above materials, the base material 11 may contain a filler or the like. Examples of the filler include silica, titanium oxide, calcium carbonate, kaolin, aluminum oxide, and the like, and one or more of these can be used in combination. 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.

In addition, the base material 11 preferably has an arithmetic average roughness Ra ₂ of the first surface 111 of ₁₀ to 200 nm and a maximum protrusion height Rp ₂ of 80 to 1000 nm.

In particular, the arithmetic average roughness Ra ₂ of the first surface 111, more preferably from 15 to 100 nm, the arithmetic mean roughness Ra ₂ of the first surface 111, more preferably, it is 20 to 50 nm. The maximum projection height Rp ₂ of the first surface 111 is more preferably from 90～800Nm, maximum projection height Rp ₂ of the first surface 111 a and even more preferably 100-600 nm.

When the arithmetic average roughness Ra ₂ and the maximum protrusion height Rp _{2 of} the first surface 111 are within the above ranges, even if the smoothing layer 12 described later has a relatively thin film thickness, The unevenness of the first surface 111 can be embedded more suitably, and the surface 121 opposite to the substrate 11 of the smoothing layer 12 can be made smoother. As a result, it is possible to more suitably prevent the unevenness of the first surface 111 of the substrate 11 from affecting the outer surface 131 of the release agent layer 13 formed on the smoothing layer 12.

In addition, the base 11 having the arithmetic average roughness Ra ₂ of the first surface 111 and the maximum protrusion height Rp ₂ within the above range is relatively inexpensive and easily available.

Further, when the arithmetic average roughness Ra ₂ of the first surface 111 exceeds the upper limit value, it is difficult to sufficiently fill the unevenness of the first surface 111 depending on the constituent material of the smoothing layer forming composition. Therefore, it may be necessary to make the release agent layer 13 relatively thick.

In the present specification, the arithmetic average roughness Ra ₂ and the maximum protrusion height Rp ₂ of the first surface 111 of the base material 11 are in accordance with JIS B0601-1994, a surface roughness measuring instrument SV3000S4 (Mitutoyo Co., Ltd.). It is a value obtained by measurement by a stylus type). In the present specification, unless otherwise specified, the “arithmetic average roughness and maximum protrusion height” refer to values obtained by measurement as described above.

Further, the substrate 11 is the arithmetic mean roughness Ra ₃ of the second surface 112 is 10 to 200 nm, and the maximum projection height Rp ₃ is preferably a 80～1000Nm. In particular, the arithmetic mean roughness Ra ₃ of the second surface 112 is more preferably from 15 to 100 nm, the arithmetic mean roughness Ra ₃ of the second surface 112 is an even more preferred 20 to 50 nm. The maximum projection height Rp ₃ of the second surface 112 is more preferably from 90～800Nm, maximum projection height Rp ₃ of the second surface 112 is an even more preferred 100-600 nm.

When the arithmetic average roughness Ra ₃ of the second surface 112 and the maximum protrusion height Rp ₃ are within the above ranges, it is preferable that winding deviation or the like occurs when the release film 1 is wound into a roll shape. In addition, it is possible to prevent the occurrence of blocking when winding and storing in a roll shape. Specifically, the release film 1 can be wound and stored in a roll shape around a core material such as paper, plastic, or metal as necessary. At this time, when the arithmetic average roughness Ra ₃ of the second surface 112 and the maximum protrusion height Rp ₃ are within the above ranges, air release is good when the release film 1 is wound into a roll shape. Thus, winding deviation can be effectively suppressed. Therefore, when winding the release film 1, it is not necessary to increase the winding tension, and it is possible to suppress the deformation of the winding core portion caused by the winding tension. In addition, when the arithmetic average roughness Ra ₃ of the second surface 112 and the maximum protrusion height Rp ₃ in the roll-shaped release film 1 are within the above ranges, the release agent layer 13 and the second base material 11 The occurrence of blocking caused by the close contact with the surface 112 can be more effectively prevented. Therefore, the roll-shaped release film 1 can be easily fed out.

On the other hand, when the arithmetic average roughness Ra ₃ of the second surface 112 is less than the lower limit value, when winding up into a roll shape, the front and back of the release film 1 (with the second surface 112 of the base material 11 and There is a possibility that blocking is likely to occur on the outer surface 131) of the release agent layer 13.

  Moreover, although the average film thickness of the base material 11 is not specifically limited, It is preferable that it is 10-300 micrometers, and it is more preferable that it is 15-200 micrometers. Thereby, while making the softness | flexibility of the peeling film 1 moderate, the tolerance with respect to tearing, a fracture | rupture, etc. can be made especially excellent.

<Smoothing layer 12>
The smoothing layer 12 has a function of reducing the influence of the unevenness of the first surface 111 of the substrate 11 on the outer surface 131 of the release agent layer 13.

As shown in FIG. 1, the smoothing layer 12 is provided on the first surface 111 of the substrate 11.
The smoothing layer 12 is composed of a smoothing layer forming composition containing a predetermined thermosetting compound. The smoothing layer 12 is formed by heating and curing.

  As described above, the smoothing layer-forming composition contains a thermosetting compound having a mass average molecular weight of 950 or less. In particular, those containing a thermosetting compound having a mass average molecular weight of 300 to 700 are preferable. Thereby, the viscosity of the composition for smoothing layer formation before apply | coating to the 1st surface 111 of the base material 11 and heating can be made moderate, and the composition for smoothing layer formation is moderate. It will have fluidity. By using such a composition for forming a smoothing layer, the smoothing layer 12 is formed on the first surface 111 side of the base material 11 so that the unevenness of the first surface 111 of the base material 11 is suitably embedded. be able to. As a result, it is possible to prevent the unevenness of the base material 11 from affecting the third surface 121 of the smoothing layer 12 and to smooth the third surface 121 of the smoothing layer 12. Therefore, it is possible to prevent the unevenness of the base material 11 from affecting the outer surface 131 of the release agent layer 13 formed on the smoothing layer 12, and to smooth the outer surface 131 of the release agent layer 13. Can be.

  In particular, even if the unevenness of the surface of the first surface 111 of the substrate 11 is relatively large, the unevenness of the first surface 111 is reduced by the action and effect of the smoothing layer forming composition as described above. Since it can be embedded suitably, the release film 1 excellent in the smoothness of the outer surface 131 of the release agent layer 13 can be obtained.

  On the other hand, when the mass average molecular weight of the thermosetting compound exceeds the upper limit, the fluidity of the composition for forming a smoothing layer is lowered, and the smoothing layer 12 is the first surface of the substrate 11. There is a risk of forming along the irregularities 111. As a result, the third surface 121 of the smoothing layer 12 may have a shape that follows the unevenness of the first surface of the substrate 11.

  Examples of the thermosetting compound having a mass average molecular weight within the above range include bisphenol type epoxy compounds such as bisphenol A type epoxy compounds, bisphenol A type epoxy ester compounds, bisphenol F type epoxy compounds, and bisphenol F type epoxy ester compounds. In addition to amino compounds such as compounds, melamine compounds, and urea compounds, isocyanate compounds, oxazoline compounds, urethane compounds, acrylic compounds, phenol compounds, alkyd compounds, polyester compounds, and the like can be given. Among these, a bisphenol type epoxy compound is particularly preferable, and a bisphenol A type epoxy ester compound is more preferable. Thereby, the unevenness of the surface of the first surface 111 of the substrate 11 can be filled more easily and reliably, and the curability is particularly excellent even with the smoothing layer 12 having a relatively thin film thickness. can do.

  Moreover, although the composition for smoothing layer formation contains the thermosetting compound in which the mass mean molecular weight is the said range, it may contain a solvent as needed. Thereby, the viscosity of the composition for smoothing layer formation at the time of apply | coating to the 1st surface 111 of the base material 11 can be adjusted easily.

  Examples of the solvent include organic solvents such as aromatic hydrocarbons such as toluene and xylene, fatty acid esters such as ethyl acetate and butyl acetate, ketones such as methyl ethyl ketone and methyl isobutyl ketone, and aliphatic hydrocarbons such as hexane and heptane. 1 type or 2 types or more of them can be used in combination. Thereby, it becomes easy to make the viscosity before apply | coating to the 1st surface 111 of the base material 11 and heating the composition for smoothing layer formation moderate.

  In addition, the composition for smoothing layer formation may contain the other component in addition to the component which was ahead. Examples of other components include a catalyst, a dye, a dispersant, an antistatic agent, and a curing agent. Moreover, when the said other component is included, it is preferable that the content rate of the said other component in the composition for smoothing layer formation (solid content conversion) is 0.1-10 mass%.

  Moreover, the content rate of the thermosetting compound in the composition for smoothing layer formation containing a solvent is although it does not specifically limit, 0.5-60 mass% is preferable and 1-45 mass% is more preferable. Thereby, it becomes easy to make the viscosity of the composition for smoothing layer formation suitable.

  Moreover, the content rate of the thermosetting compound in the composition for smoothing layer formation (solid content conversion) is although it does not specifically limit, 90 mass% or more is preferable and 95 mass% or more is more preferable. Thereby, the sclerosis | hardenability of the composition for smoothing layer formation can be made especially excellent.

Also, arithmetic mean roughness of the third surface 121 of the smoothing layer 12 Ra ₄ is a 8nm or less, and preferably has a maximum projection height Rp ₄ is 50nm or less. Particularly, preferred arithmetic average roughness Ra ₄ of the third surface 121 that is 6nm or less. In addition, it is preferable that the maximum protrusion height Rp ₄ of the third surface 121 is 40 nm or less.

When the arithmetic average roughness Ra ₄ and the maximum protrusion height Rp _{4 of} the third surface 121 are within the above ranges, the influence of the unevenness of the surface of the base material 11 on the outer surface 131 of the release agent layer 13 is more preferably applied. Can be prevented.

On the other hand, if the arithmetic average roughness Ra ₄ of the third surface 121 is less than the lower limit value, the adhesiveness to the release agent layer 13 may be lowered depending on the constituent material of the smoothing layer 12 and the like. is there. On the other hand, when the arithmetic average roughness Ra ₄ of the third surface 121 exceeds the upper limit, it may be necessary to provide a new smoothing layer between the release agent layer 13 and the smoothing layer 12. .

Further, if the maximum protrusion height Rp ₄ of the third surface 121 is less than the lower limit value, in order to improve the adhesion with the release agent layer 13, on the third surface 121 of the smoothing layer 12, In some cases, it is necessary to perform a treatment for improving the adhesion. On the other hand, if the maximum protrusion height Rp ₄ of the third surface 121 exceeds the upper limit, it may be necessary to provide a new smoothing layer between the release agent layer 13 and the smoothing layer 12. .

  Moreover, the average film thickness of the smoothing layer 12 is not specifically limited, However, It is preferable that it is 0.2-10 micrometers, and it is more preferable that it is 0.3-5 micrometers. Thereby, the unevenness | corrugation of the 1st surface 111 of the base material 11 can be embedded more correctly, and the smoothness of the outer surface of the peeling film 1 can be made higher. Moreover, the softness | flexibility of the smoothing layer 12 can be made moderate.

  On the other hand, if the average film thickness of the smoothing layer 12 is less than the lower limit value, the unevenness of the first surface 111 of the substrate 11 may be sufficient depending on the components constituting the smoothing layer forming composition. Therefore, it may be necessary to use the first surface 111 having a relatively small surface roughness. Moreover, when the average film thickness of the smoothing layer 12 exceeds the above upper limit, depending on the components constituting the composition for forming the smoothing layer, curling of the release film 1 is likely to occur due to curing shrinkage of the smoothing layer 12. Therefore, the handleability of the release film 1 may be reduced.

<Release layer 13>
The release agent layer 13 has a function of imparting peelability to the release film 1.

  As shown in FIG. 1, the release agent layer 13 is provided on the third surface 121 side of the smoothing layer 12.

The release agent layer 13 is a layer formed by applying a release agent layer forming composition to the third surface 121 of the smoothing layer 12, drying and curing.
Such a composition for forming a release agent layer contains a release agent.

  Examples of the release agent include alkyd compounds, acrylic compounds, silicone compounds, long-chain alkyl group-containing compounds, fluorine compounds, and the like, and one or more of these can be used in combination. Among these, it is preferable to use an alkyd compound, an acrylic compound, a silicone compound, or a long-chain alkyl group-containing compound. As a result, it is possible to obtain the release agent layer 13 that has an appropriate curability and is particularly excellent in the peelability to the green sheet.

  Specific examples of alkyd compounds include modified products such as long-chain alkyl-modified alkyd compounds and silicone-modified alkyd compounds. When an alkyd compound is used, a release agent layer 13 having an alkyd compound having a crosslinked structure is added to the release agent layer forming composition by a method in which a crosslinking agent or a catalyst is further added and cured. Can be obtained.

  In addition, as the acrylic compound, for example, a modified product such as a long-chain alkyl-modified acrylic compound or a silicone-modified acrylic compound can be used. In addition, when the release agent layer forming composition contains an acrylic compound, the release agent layer forming composition is further added with a crosslinking agent or a catalyst, and then heated and cured to form an acrylic resin having a crosslinked structure. Thus, the release agent layer 13 having a system compound can be obtained.

  Moreover, as a silicone type compound, the silicone type compound etc. which have a dimethylpolysiloxane as a basic skeleton can be used for a specific example. Examples of the silicone compound include an addition reaction type, a condensation reaction type, an ultraviolet curable type, and an electron beam curable type. The addition reaction type silicone compound has high reactivity and excellent productivity, and has advantages such as little change in peel force after production and no cure shrinkage compared to the condensation reaction type. It is preferable to use it as a constituent release agent.

  As a specific example of the above addition reaction type silicone compound, two or more alkenyl groups having 2 to 10 carbon atoms such as vinyl group, allyl group, propenyl group, hexenyl group and the like are provided at the terminal and / or side chain of the molecule. Organopolysiloxane is mentioned. When such an addition reaction type silicone compound is used, it is preferable to use a crosslinking agent and a catalyst in combination.

  Examples of the crosslinking agent include, for example, organopolysiloxane having hydrogen atoms bonded to at least two silicon atoms in one molecule, specifically, a dimethylhydrogensiloxy group end-capped dimethylsiloxane-methylhydrogensiloxane copolymer. , Trimethylsiloxy group end-capped dimethylsiloxane-methylhydrogensiloxane copolymer, trimethylsiloxy group end-capped methylhydrogenpolysiloxane, poly (hydrogensilsesquioxane), and the like.

  Examples of the catalyst include finely divided platinum, finely divided platinum adsorbed on a carbon powder carrier, chloroplatinic acid, alcohol-modified chloroplatinic acid, olefin complexes of chloroplatinic acid, white metal compounds such as palladium and rhodium, etc. Is mentioned. By using such a catalyst, the curing reaction of the composition for forming a release agent layer can be advanced more efficiently.

  Examples of the long chain alkyl compound include polyvinyl carbamate obtained by reacting a polyvinyl alcohol polymer with a long chain alkyl isocyanate having 8 to 30 carbon atoms, or polyethyleneimine and a long chain having 8 to 30 carbon atoms. An alkyl urea derivative obtained by reacting an alkyl isocyanate is used.

  Moreover, as a fluorine compound, a fluorine silicone compound, a fluorine boron compound, etc. can be used for a specific example.

  Further, the release agent layer forming composition may contain a dispersion medium and a solvent in addition to the release agent described above. By including at least one of the dispersion medium and the solvent, the viscosity of the composition for forming the release agent layer before applying to the third surface 121 of the smoothing layer 12 and drying can be made appropriate. it can.

  Examples of the dispersion medium or solvent include aromatic solvents such as toluene, fatty acid esters such as ethyl acetate, ketones such as methyl ethyl ketone, and organic solvents such as aliphatic hydrocarbons such as hexane and heptane. Species or a combination of two or more can be used.

  In addition to the components as described above, the release agent layer forming composition may contain other components. Examples of other components include a catalyst, a dye, a dispersant, an antistatic agent, and a curing agent. Moreover, when the said other component is included, it is preferable that the content rate of the said other component in the composition for peeling agent layer forming is 0.1-10 mass%.

As described above, the outer surface 131 of the release agent layer 13 has an arithmetic average roughness Ra ₁ of 8 nm or less, and a maximum protrusion height Rp ₁ of 50 nm or less. In particular, the arithmetic mean roughness Ra ₁ of the outer surface 131 of the release agent layer 13 is preferably 6 nm or less. In addition, the maximum protrusion height Rp ₁ of the outer surface 131 of the release agent layer 13 is preferably 40 nm or less.

When the arithmetic average roughness Ra ₁ and the maximum protrusion height Rp ₁ of the outer surface 131 of the release agent layer 13 are within the above ranges, a relatively high smooth surface shape of the outer surface 131 is formed when the green sheet is formed. By being transferred to the green sheet, pinholes and the like can be more suitably prevented from occurring on the surface of the green sheet. As a result, a green sheet having a higher smooth surface can be obtained.

  Further, the release agent layer 13 preferably has an average film thickness of 0.01 to 3 μm, and more preferably 0.03 to 1 μm. If the thickness of the release agent layer 13 is less than 0.01 μm, the function as the release agent layer may not be sufficiently exhibited depending on the material constituting the release agent layer 13 or the like. On the other hand, when the thickness of the release agent layer 13 exceeds 3 μm, blocking tends to occur when the release film 1 is wound up in a roll shape. Problems such as highs may occur.

<Method for producing release film for producing green sheet>
Next, a preferred embodiment of the method for producing the release film 1 for producing a green sheet as described above will be described.

  The manufacturing method of the peeling film 1 of this embodiment is a base material preparation process which prepares the base material 11, and apply | coats an application layer by apply | coating and drying the composition for smoothing layer formation containing a predetermined thermosetting compound. On the surface 121 side of the smoothing layer 12 opposite to the substrate 11, the coating layer forming step to be formed, the smoothing layer forming step of forming the smoothing layer 12 by heating and curing the coating layer, A release agent layer forming step for forming the release agent layer 13.

Hereinafter, each step will be described in detail.
<Base material preparation process>
First, the base material 11 is prepared.
As the base material 11, the base material 11 having the configuration described above can be used.

  Further, the first surface 111 of the substrate 11 can be subjected to a surface treatment such as an oxidation method or a primer treatment. Thereby, the adhesiveness of the base material 11 and the smoothing layer 12 provided in the 1st surface 111 side of the base material 11 can be made especially excellent.

  The surface treatment by the oxidation method or the like may be appropriately selected according to the type of the substrate 11 and the like. For example, corona discharge treatment, plasma discharge treatment, chromium oxidation treatment (wet), flame treatment, hot air treatment, ozone treatment And ultraviolet irradiation treatment. Among these, it is more preferable to use a corona discharge treatment because it has excellent adhesion to the smoothing layer 12 and the treatment operation is simple.

<Coating layer formation process>
In this step, first, a smoothing layer forming composition is prepared.

  As the composition for forming a smoothing layer, the thermosetting compound as described above may be used alone, or in addition to this, a mixture of a solvent and other components as described above may be used as necessary. May be.

  Next, a liquid smoothing layer forming composition is applied onto the first surface 111 of the substrate 11. Thereby, a coating layer is obtained. As described above, since the smoothing layer-forming composition has an appropriate fluidity, the smoothing layer-forming composition is applied onto the first surface 111 of the substrate 11 and dried. Thereby, the unevenness | corrugation of the 1st surface 111 of the base material 11 can be filled exactly, and the coating layer with a smooth outer surface can be obtained.

  Examples of the method for applying the smoothing layer forming composition 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, Examples include a die coating method. Among these, the gravure coating method and the bar coating method are more preferable, and the bar coating method is more preferable. Thereby, the coating layer of the target thickness can be formed easily.

<Smoothing layer forming step>
Next, the smoothing layer 12 is formed by heating and hardening the coating layer obtained by the coating layer formation process.

  In this step, the coating layer in which the unevenness of the first surface 111 of the substrate 11 is appropriately embedded in the coating layer forming step is cured while maintaining the smoothness of the outer surface. As a result, the smoothing layer 12 having a sufficiently smooth third surface 121 can be obtained. Thereby, the influence of the unevenness | corrugation of the 1st surface 111 of the base material 11 with respect to the outer surface 131 of the releasing agent layer 13 can be prevented more suitably. Therefore, the smoothness of the outer surface 131 of the release agent layer 13 can be made excellent in the release agent layer forming step described later.

  Although it does not specifically limit as a heating method, For example, the method etc. which heat with a hot air drying furnace etc. are mentioned.

  Moreover, it does not specifically limit as heating conditions, However, It is preferable that heating temperature is 80-150 degreeC, and it is preferable that heating time is 5 second-1 minute. Thereby, unintentional alteration of the smoothing layer 12 can be prevented, and the smoothing layer 12 can be formed particularly efficiently. As a result, productivity of the finally obtained release film 1 can be improved. Further, when the heating temperature is within the above range, when the smoothing layer forming composition contains a solvent or the like, warping or cracking of the smoothing layer 12 accompanied by evaporation of the solvent or the like during heating occurs. Can be especially prevented.

<Release agent layer forming step>
Next, the release agent layer 13 is formed on the surface 121 side of the smoothing layer 12 opposite to the substrate 11.

  As the release agent layer forming composition constituting the release agent layer 13, a mixture of materials as described above is prepared.

  Subsequently, after apply | coating the liquid release agent layer forming composition on the surface 121 opposite to the base material 11 of the smoothing layer 12, the release agent layer 13 is obtained by drying and hardening.

  Although it does not specifically limit as a drying method, For example, the drying method using a hot air drying furnace etc. is mentioned.

  Moreover, it is although it does not specifically limit as drying conditions, It is preferable that drying temperature is 80-150 degreeC, and it is preferable that drying time is 5 second-1 minute. Thereby, unintentional alteration of the release agent layer 13 can be prevented, and the release agent layer 13 can be formed particularly efficiently. As a result, productivity of the finally obtained release film 1 can be improved.

  According to the above process, the reliable peeling film 1 which was excellent in smoothness and excellent in peelability can be manufactured easily and reliably.

  Moreover, if a green sheet is manufactured using such a peeling film 1, it can prevent that a pinhole etc. arise on the surface of a green sheet.

  In addition, as a method of manufacturing a ceramic green sheet using the release film 1, for example, a ceramic powder-dispersed slurry is applied to the surface of the release agent layer of the release film and dried to form a green sheet. A method may be mentioned in which electrodes are formed on a ceramic sheet obtained by laminating and firing the peeled green sheets. Thereby, a ceramic capacitor can be obtained. Thus, if a ceramic capacitor is formed with a green sheet formed using the release film 1, a highly reliable ceramic capacitor in which the occurrence of problems due to a short circuit is prevented can be obtained.

  As mentioned above, although this invention was demonstrated in detail based on preferred embodiment, this invention is not limited to this.

  For example, in the above-described embodiment, the base material has been described as having a single layer structure, but the present invention is not limited to this, and the base material may have a multilayer structure of two or more layers of the same type or different types. In addition, the smoothing layer and the release agent layer are similarly described as having a single layer structure, but the present invention is not limited to this, and the smoothing layer and the release agent layer are each of the same or different two or more layers. It may have a multilayer structure.

  Further, for example, in the embodiment described above, the release film for producing a green sheet is described as having a three-layer structure in which a base material, a smoothing layer, and a release agent layer are laminated in this order. However, the present invention is not limited to this, and an intermediate layer may be provided between the smoothing layer and the release agent layer. Moreover, you may provide an intermediate | middle layer between a base material and a smoothing layer. Such an intermediate layer may be one that improves the adhesion between the smoothing layer and the release agent layer, and is charged when the release film for producing the green sheet before winding the green sheet is wound up. You may suppress generation | occurrence | production more.

  Moreover, the manufacturing method of the peeling film for green sheet manufacture of this invention is not limited to the method mentioned above, Arbitrary processes may be added as needed.

  Next, although the specific Example of the peeling film for green sheet manufacture of this invention is described, this invention is not limited only to these Examples.

[1] Production of release film for green sheet production (Example 1)
First, a biaxially stretched polyethylene terephthalate film as a substrate [thickness: 38 μm, arithmetic average roughness Ra ₂ of the first surface: 42 nm, maximum protrusion height Rp _{2 of} the first surface: 619 nm, of the second surface Arithmetic average roughness Ra ₃ : 42 nm, maximum protrusion height Rp ₃ : 619 nm on the second surface] was prepared.

  Next, 100 parts by mass of a bisphenol A type epoxy ester compound as a thermosetting compound [“TA31-059D” manufactured by Hitachi Chemical Co., Ltd., solid content concentration 50 mass%, mass average molecular weight 530], and p- 3 parts by mass of toluenesulfonic acid, toluene, and methyl ethyl ketone were mixed to obtain a composition for forming a smoothing layer having a solid content of 20% by mass.

  The obtained composition for smoothing layer formation was apply | coated to the 1st surface of a base material with Mayer bar # 4, and the coating layer was obtained.

  Next, the coating layer was heated at 130 ° C. for 1 minute to form a smoothing layer (thickness: 1.3 μm).

  Furthermore, 100 parts by mass of a mixture of an addition reaction type silicone compound as a release agent and a crosslinking agent [manufactured by Shin-Etsu Chemical Co., Ltd., trade name “silicone KS-847H”, solid content 30% by mass] with toluene, 2 parts by mass of a platinum catalyst [trade name “PL-50T” manufactured by Shin-Etsu Chemical Co., Ltd.] was added to and mixed with a composition for forming a release agent layer having a solid content of 1.5% by mass. It coated uniformly on the surface opposite to the base material of the said smoothing layer so that the thickness after drying might be set to 0.1 micrometer. Then, it was made to dry at 130 degreeC for 1 minute, the release agent layer was formed, and the release film for green sheet manufacture was produced.

(Example 2)
The biaxially stretched polyethylene terephthalate film of Example 1 was converted into a biaxially stretched polyethylene terephthalate film [thickness 31 μm, arithmetic mean roughness Ra ₂ of the first surface: 29 nm, maximum protrusion height Rp ₂ : 257 nm of the first surface, A release film for producing a green sheet was produced in the same manner as in Example 1 except that the arithmetic average roughness Ra ₃ of the second surface was 29 nm and the maximum protrusion height Rp _{3 was} 257 nm of the second surface. .

(Example 3)
The biaxially stretched polyethylene terephthalate film of Example 1 was converted into a biaxially stretched polyethylene terephthalate film [thickness 31 μm, arithmetic mean roughness Ra ₂ of the first surface: 15 nm, maximum projection height Rp _{2 of} first surface: 98 nm, Example 1 except that the arithmetic average roughness Ra ₃ of the second surface was changed to 15 nm and the maximum protrusion height Rp _{3 of} the second surface was 98 nm, and the thickness of the smoothing layer was changed to 0.4 μm. In the same manner as described above, a release film for producing a green sheet was produced.

Example 4
A release film for producing a green sheet was produced in the same manner as in Example 1 except that the thickness of the smoothing layer in Example 1 was changed to 1.8 μm.

(Example 5)
A release film for producing a green sheet was produced in the same manner as in Example 1 except that the thickness of the smoothing layer in Example 1 was changed to 2.3 μm.

(Comparative Example 1)
First, a biaxially stretched polyethylene terephthalate film as a substrate [thickness: 38 μm, arithmetic average roughness Ra ₂ of the first surface: 42 nm, maximum protrusion height Rp _{2 of} the first surface: 619 nm, of the second surface Arithmetic average roughness Ra ₃ : 42 nm, maximum protrusion height Rp ₃ : 619 nm on the second surface] was prepared.

  Next, 100 parts by mass of a mixture of an addition reaction type silicone compound as a release agent and a crosslinking agent [manufactured by Shin-Etsu Chemical Co., Ltd., trade name “silicone KS-847H”, solid content 30% by mass] with toluene, To this was added 2 parts by mass of a platinum catalyst [trade name “PL-50T” manufactured by Shin-Etsu Chemical Co., Ltd.] and mixed to obtain a release agent layer-forming composition having a solid content of 1.5% by mass. Then, it was applied uniformly on the first surface of the substrate so that the thickness after drying was 0.1 μm. Then, it was made to dry at 130 degreeC for 1 minute, the release agent layer was formed, and the release film for green sheet manufacture was produced.

(Comparative Example 2)
First, a biaxially stretched polyethylene terephthalate film as a substrate [thickness: 38 μm, arithmetic average roughness Ra ₂ of the first surface: 42 nm, maximum protrusion height Rp _{2 of} the first surface: 619 nm, of the second surface Arithmetic average roughness Ra ₃ : 42 nm, maximum protrusion height Rp ₃ : 619 nm on the second surface] was prepared.

  Next, a mixture of a stearyl-modified alkyd compound and a methylated melamine compound as a thermosetting compound [manufactured by Hitachi Chemical Co., Ltd., trade name “Tesfine 303”, solid content 20 mass%, mass average molecular weight 15000] 100 mass Part and 3 parts by mass of p-toluenesulfonic acid as an acid catalyst were mixed to obtain a smoothing layer forming composition.

  The obtained composition for smoothing layer formation was apply | coated to the 1st surface of a base material with Mayer bar # 4, and the coating layer was obtained.

  Next, the coating layer was heated at 130 ° C. for 1 minute to form a smoothing layer (thickness: 1.0 μm).

  Furthermore, 100 parts by mass of a mixture of an addition reaction type silicone compound as a release agent and a crosslinking agent [manufactured by Shin-Etsu Chemical Co., Ltd., trade name “silicone KS-847H”, solid content 30% by mass] with toluene, 2 parts by mass of a platinum catalyst [trade name “PL-50T” manufactured by Shin-Etsu Chemical Co., Ltd.] was added to and mixed with a composition for forming a release agent layer having a solid content of 1.5% by mass. It coated uniformly on the surface opposite to the base material of the said smoothing layer so that the thickness after drying might be set to 0.1 micrometer. Then, it was made to dry at 130 degreeC for 1 minute, the release agent layer was formed, and the release film for green sheet manufacture was produced.

(Comparative Example 3)
First, a biaxially stretched polyethylene terephthalate film as a substrate [thickness: 38 μm, arithmetic average roughness Ra ₂ of the first surface: 42 nm, maximum protrusion height Rp _{2 of} the first surface: 619 nm, of the second surface Arithmetic average roughness Ra ₃ : 42 nm, maximum protrusion height Rp ₃ : 619 nm on the second surface] was prepared.

  Next, 80 parts by mass of a polyester compound [manufactured by Toyobo Co., Ltd., trade name “Byron 20SS”, solid content 30% by mass, mass average molecular weight 3000] as a thermosetting compound, and a methylated melamine compound as a crosslinking agent 20 parts by mass, 3 parts by mass of p-toluenesulfonic acid as an acid catalyst, and toluene were mixed with methyl ethyl ketone to obtain a composition for forming a smoothing layer having a solid content of 20% by mass.

  The obtained composition for smoothing layer formation was apply | coated to the 1st surface of a base material with Mayer bar # 4, and the coating layer was obtained.

  Next, the coating layer was heated at 130 ° C. for 1 minute to form a smoothing layer (thickness 1.2 μm).

  Furthermore, 100 parts by mass of a mixture of an addition reaction type silicone compound as a release agent and a crosslinking agent [manufactured by Shin-Etsu Chemical Co., Ltd., trade name “silicone KS-847H”, solid content 30% by mass] with toluene, 2 parts by mass of a platinum catalyst [trade name “PL-50T” manufactured by Shin-Etsu Chemical Co., Ltd.] was added to and mixed with a composition for forming a release agent layer having a solid content of 1.5% by mass. It coated uniformly on the surface opposite to the base material of the said smoothing layer so that the thickness after drying might be set to 0.1 micrometer. Then, it was made to dry at 130 degreeC for 1 minute, the release agent layer was formed, and the release film for green sheet manufacture was produced.

  Table 1 summarizes the configurations and the like of the release films for producing green sheets of each Example and each Comparative Example.

  In the table, bisphenol A type epoxy ester compound [Hitachi Kasei Polymer Co., Ltd. “TA31-059D”, solid content concentration 50 mass%] as thermosetting compound is “A1”, stearyl modification as thermosetting compound Mixture of alkyd compound and methylated melamine compound [manufactured by Hitachi Chemical Co., Ltd., trade name “Tesfine 303”, solid content 20% by mass] “A2”, polyester compound as a thermosetting compound [Toyobo Co., Ltd. ), Trade name “Byron 20SS”, solid content 30% by mass] is indicated as “A3”.

  Moreover, the film thickness of the base material of each Example and each comparative example, the smoothing layer, and the release agent layer was measured with a reflective film thickness meter “F20” [manufactured by Filmetrics Co., Ltd.].

Further, the arithmetic average roughness Ra ₂ and the maximum protrusion height Rp ₂ of the first surface of the base material, the arithmetic average roughness Ra ₃ and the maximum protrusion height Rp ₃ of the second surface of the base material, and the smoothing layer The arithmetic average roughness Ra ₄ and the maximum protrusion height Rp _{4 of} the third surface, the arithmetic average roughness Ra ₁ and the maximum protrusion height Rp ₁ of the outer surface of the release agent layer, respectively, a double-sided tape affixed to the glass plate And fixed on the double-sided tape so that the surface opposite to the surface to be measured is on the glass plate side, using a surface roughness measuring instrument SV3000S4 (stylus type) manufactured by Mitutoyo Corporation in accordance with JIS B0601-1994. It was measured.

[2] Evaluation Regarding the release film for producing a green sheet obtained as described above, the following evaluation was performed.

[2.1] Evaluation of blocking property The release film for producing a green sheet obtained in each example and each comparative example was wound into a roll having a width of 400 mm and a length of 5000 m. This release film roll was stored in an environment of 40 ° C. and a humidity of 50% or less for 30 days, the appearance of the release film roll was visually observed, and the blocking property was evaluated according to the following criteria.

A: There was no change from when it was rolled up (no blocking)
B: There was a region where the color was partially different (can be used although it tends to be blocking)
C: Color was different over a wide area (with blocking)
When blocking due to adhesion between the front and back surfaces occurs as in the evaluation C and the color changes over a wide area of the release film roll, the film may not be normally unwound.

[2.2] Evaluation of the number of dents A release film for producing a green sheet obtained in each example and each comparative example was obtained by using a coating solution obtained by dissolving polyvinyl butyral resin in a toluene / ethanol mixed solvent (mass ratio 6/4). The release agent layer was coated on the outer surface (outer surface) so that the thickness after drying was 3 μm, and dried at 80 ° C. for 1 minute to form a polyvinyl butyral resin layer. Next, a polyester tape was attached to the surface of the polyvinyl butyral resin layer. Next, the release film for green sheet production was peeled from the polyvinyl butyral resin layer, and the polyvinyl butyral resin layer was transferred to a polyester tape. Next, with respect to the surface of the polyvinyl butyral resin layer that was in contact with the release agent layer of the release film for producing the green sheet, the PSI mode was used using a light interference type surface shape observation device “WYKO-1100” [manufactured by Veeco Corporation]. The number of dents with a depth of 150 nm or more to which the shape of the release agent layer confirmed in the range of 91.2 × 119.8 μm was transferred was counted at 50 magnifications, and evaluated according to the following criteria. In addition, when a capacitor was produced with a green sheet having a dent of the following evaluation C, a short circuit due to a decrease in withstand voltage tended to occur.

A: When the number of dents is 0 B: When the number of dents is 1 to 5 C: When the number of dents is 6 or more These results are shown in Table 2.

  As is clear from Table 2, the release film for producing the green sheet of the present invention was excellent in the smoothness of the outer surface. Moreover, the coarse dent etc. were hardly confirmed by the green sheet formed using the peeling film for green sheet manufacture of this invention. Moreover, generation | occurrence | production of malfunctions, such as a short circuit, was not confirmed by the ceramic capacitor manufactured with the green sheet formed using the peeling film for green sheet manufacture of this invention. On the other hand, satisfactory results were not obtained in the comparative example.

DESCRIPTION OF SYMBOLS 1 ... Release film 11 for green sheet manufacture ... Base material 111 ... 1st surface 112 of a base material ... 2nd surface 12 of a base material 12 ... Smoothing layer 121 ... Surface (Third aspect)
13 ... Release agent layer 131 ... Outer surface of release agent layer

Claims (7)

A release film for producing a green sheet used for producing a green sheet,
A substrate having a first surface and a second surface;
A smoothing layer provided on the first surface side of the substrate;
A release agent layer provided on the surface side opposite to the base material of the smoothing layer,
The smoothing layer is formed by heating and curing a composition for forming a smoothing layer containing a thermosetting compound having a mass average molecular weight of 950 or less,
The arithmetic average roughness Ra ₁ of the outer surface of the release agent layer is 8 nm or less, and the maximum protrusion height Rp ₁ of the outer surface of the release agent layer is 50 nm or less. Release film. The arithmetic mean roughness of the first surface Ra ₂ is 10 to 200 nm, and the first maximum projection height Rp ₂ of surface peeling green sheet produced according to claim 1 which is 80~1000nm the film.   The release film for producing a green sheet according to claim 1 or 2, wherein the smoothing layer has an average film thickness of 0.2 to 10 µm.   The release film for producing a green sheet according to any one of claims 1 to 3, wherein the thermosetting compound is a bisphenol type epoxy compound. The arithmetic average roughness Ra ₄ of the surface of the smoothing layer opposite to the substrate is 8 nm or less, and the maximum protrusion height Rp ₄ of the surface of the smoothing layer opposite to the substrate is 50 nm or less. The release film for manufacturing a green sheet according to any one of claims 1 to 4. The arithmetic average roughness Ra ₃ of the second surface is 10 to 200 nm, and, in any one of from the maximum projection height Rp ₃ of the second surface is no claim 1 wherein 80～1000Nm 5 The release film for green sheet manufacture as described. It is a manufacturing method of the peeling film for green sheet manufacture of any one of Claim 1 thru | or 6, Comprising:
A base material preparing step of preparing the base material having the first surface and the second surface;
A coating layer forming step of forming a coating layer by coating the smoothing layer forming composition containing the thermosetting compound having a mass average molecular weight of 950 or less on the first surface side of the substrate;
A smoothing layer forming step of forming the smoothing layer by heating and curing the coating layer;
A release agent layer forming step of forming the release agent layer on the surface side of the smoothing layer opposite to the substrate;
The arithmetic average roughness Ra ₁ of the outer surface of the release agent layer is 8 nm or less, and the maximum protrusion height Rp ₁ of the outer surface of the release agent layer is 50 nm or less. A method for producing a release film.

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