JP2003055894A - Process release paper for producing ceramic green sheet and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide process release paper for producing a ceramic green sheet composed by changing a PET or OPP-based process release film having been used as a base into a paper-based sheet, and to provide a method for producing the same. SOLUTION: This process release paper for forming the ceramic green sheet, comprising coating a solvent-based ceramic slurry and then hardening the slurry, is composed by forming a cast coating layer not containing both calcium carbonate and sodium salt on a support for the process release paper and then coating a solvent-free silicone on the surface of the cast coating layer to form the solvent-free silicone layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a release sheet (casting sheet) for producing a ceramic green sheet used for a ceramic multilayer capacitor and a method for producing the release sheet.

[0002]

2. Description of the Related Art In response to the trend toward lighter, thinner, shorter, and smaller electronic devices, multilayer ceramic capacitors, which are made into chip components by alternately laminating dielectric ceramics (barium titanate etc.) thin films and internal electrodes, are widely used. ing. As a manufacturing method of this ceramic product, there are a green sheet method for forming a green sheet (green sheet before sintering) by a doctor blade method and a powder pressing method, but the green sheet method is generally used.

The production of a green sheet by the doctor blade method is carried out by scraping a slurry consisting of ceramic powder, an organic binder, a plasticizer and a solvent onto a carrier film with a doctor blade to a certain thickness, drying the solvent and solidifying the carrier. It is to separate the film from the film and wind the green sheet.

The features of this green sheet forming method are that a certain thickness can be easily obtained by setting a doctor blade, and the green sheet can be easily handled and processed.
It has the advantage that it can be laminated, has a higher packing density of green sheets compared to the press molding method, but requires a forming device with a wide floor area, uses an organic solvent, and uses a carrier film There are disadvantages such as difficulty in smoothing the opposite surface.

Generally, as a casting sheet, P
A release film made of ET film is used,
The film thickness is 2 according to the width of the doctor blade.
It ranges from 5 μm to 188 μm. Silicone is used as a release agent.

Doctor blade method (organic solvent slurry)
The quality required for a release film in the green sheet manufacturing process is that the film has a uniform thickness, it has an appropriate level of release performance, and it can be used repeatedly. No release, uniform release performance (no unevenness of silicone coating or streaks), and the ceramic is a solvent-based slurry, so the release-treated surface has solvent resistance and surface smoothness. It is good in that it does not shrink due to heat, has no foreign matter, paper dust, dust, etc., and is not charged with static electricity.

Conventionally, the above-mentioned release film has been used in the manufacturing process of a monolithic ceramic capacitor, but there is a demand to replace it with a paper base in terms of cost and recyclability. Therefore, the surface smoothness of the release film, the coating uniformity of the ceramic slurry, the easy release of the green sheet after drying, the dimensional stability, and the solvent quality (toluene alcohol) of the process paper that meets the required quality. There is an urgent need to consider using a computer.

[0008]

SUMMARY OF THE INVENTION A first object of the present invention is to use a PET or OPP-based process release film, which is currently used as a substrate, in paper-based ceramics. An object is to provide a release paper for a green sheet manufacturing process. In particular, even after the base material is made into a paper base, the thickness of the release paper in the process is uniform, has an appropriate level of release performance, and can be repeatedly used. Peeling performance is uniform, even with solvent-based ceramic slurry, the treated surface has solvent resistance and good surface smoothness,
It is an object of the present invention to provide a release sheet for producing a ceramic green sheet, which has necessary properties such as no foreign matter, paper dust, dust, etc. and no static electricity.

A second object of the present invention is to provide a solvent-based ceramic slurry containing barium titanate, barium zirconate,
(EN) It is intended to provide a process release paper for producing a ceramic green sheet, which is suitable when it contains an acrylic binder, toluene and ethanol.

A third object of the present invention is to provide a release sheet for producing a ceramic green sheet, in which ceramic coatability and ceramic releasability are stably obtained by defining the coating amount of solvent-free silicone. Especially.

The fourth object of the present invention is JISB-0601 on the surface of release paper for the production process of ceramic green sheets.
By providing the center line average roughness and the maximum roughness by the method, it is possible to provide a release sheet for producing a ceramic green sheet in which surface unevenness due to transfer on the surface of the green sheet is suppressed.

A fifth object of the present invention is to produce a ceramic green sheet by which the smoothness of the surface of the green sheet can be kept above a certain level by defining the surface smoothness of the release paper for the production step of the ceramic green sheet. To provide a process release paper.

A sixth object of the present invention is to provide a support with an ECF.
(Chlorine-free bleaching) The purpose of the present invention is to provide a release paper for the production process of ceramic green sheets that has a low chlorine load on the environment.

A seventh object of the present invention is to provide an optimum method for manufacturing a release paper for process for manufacturing a ceramic green sheet according to the present invention.

An eighth object of the present invention is to provide a method of manufacturing a release paper for a ceramic green sheet, which is excellent in surface smoothness and has a small surface roughness.

[0016]

A process release paper for producing a ceramic green sheet according to the present invention is a process release paper for forming a ceramic green sheet by coating a solvent-based ceramic slurry and then curing it. The step release paper forms a cast coating layer on the support of the step release paper, the cast coating layer contains neither calcium carbonate nor sodium salt, and the cast coating layer is the cast It is characterized in that solventless silicone is applied and formed on the surface of the coating layer.

In the release paper for producing a ceramic green sheet according to the present invention, it is preferable that the solvent-based ceramic slurry contains barium titanate, barium zirconate, an acrylic binder, toluene and ethanol.

In the release paper for producing a ceramic green sheet according to the present invention, the cast coating layer is formed by coating the surface of the cast coating layer with a dry coating amount of 0.1 g / m ² or more. It is preferably formed.

In the process release paper for producing a ceramic green sheet according to the present invention, the process release paper has a center line average roughness of 1.0 μm or less and a maximum roughness of JIS B-0601 on the surface of the process release paper. Is preferably 10 μm or less.

In the process release paper for producing a ceramic green sheet according to the present invention, the process release paper has a surface smoothness of 1 defined by Oken type smoothness.
It is preferably 500 seconds or more.

In the release paper for producing a ceramic green sheet according to the present invention, the support preferably contains ECF (chlorine-free bleaching) pulp.

The method for producing a release sheet for a ceramic green sheet according to the present invention is a method for producing a release sheet for a step for forming a ceramic green sheet by coating a solvent-based ceramic slurry and then curing it. After coating a coating solution for casting containing neither calcium carbonate nor sodium salt on the support of the release paper to form a coating layer, heating while the coating layer is in a wet state It is characterized in that the mirror coated drum surface is pressure-contacted, dried and released to form a cast coated paper, and then a solventless silicone is applied to the surface of the cast coated paper.

According to the method for producing a release paper for a process for producing a ceramic green sheet according to the present invention, in the method for producing a release paper for a process for producing a ceramic green sheet according to claim 7, a casting coating is applied on a support of the release paper for the production process. After forming the coating layer by coating the coating solution, immediately after pressing the heated mirror surface of the drum, after drying, releasing, or after gelling, while the coating layer is in a wet state After press contact with the heated specular drum surface, drying and then releasing, or after rewetting treatment, press contact with the heated specular drum surface while the coating layer is in a wet state, dry and then release. It is preferable to form cast coated paper.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to embodiments and examples, but the present invention is not construed as being limited to these embodiments and examples. The materials used and the manufacturing conditions for manufacturing the release paper of the present invention will be described.

As the cast coated paper used in the present invention, a cast coated paper having a center line average roughness of 1.0 μm or less and a maximum roughness of 10 μm or less is used. By using such a cast coated paper, the surface roughness of the release sheet after the solventless silicone is applied and formed has a center line average roughness of 1.0 μm or less and a maximum roughness. Can be 10 μm or less.

The cast coating layer preferably contains neither calcium carbonate nor sodium salt (salt, etc.) which adversely affects the product ceramic. Examples of the pigment used in the cast coating layer include kaolin other than calcium carbonate, satin white, inorganic pigments such as titanium oxide and aluminum hydroxide, and plastic pigments, but are not particularly limited thereto.

As the binder used in the cast coating layer, proteins such as casein, soybean protein and synthetic protein,
Various starches such as starch and oxidized starch, polyvinyl alcohol, modified polyvinyl alcohol, cellulose derivatives such as carboxymethyl cellulose and methyl cellulose, styrene / butadiene copolymer, conjugated diene polymer latex of methyl / methacrylate butadiene copolymer, acrylic Polymeric polymer latexes, vinylic polymer latexes such as ethylene / vinyl acetate copolymers, polyesters, polyurethanes, and other conventionally known binders generally used for coated papers, and these may be used alone or in combination. Can be used.

The mixing ratio of the pigment and the binder is as follows:
The range of 10 to 100 parts by weight is preferable with respect to 0 parts by weight.

The coating amount of the cast coating layer is 2 to 30 g / m
² and more preferably 5 to ²⁰ g / m ² .

The coating liquid used for the cast coating layer includes
If necessary, a dispersant, a wetting agent, a release agent, a water-proofing agent, an antifoaming agent, a pH adjusting agent, a lubricant, a water retention agent, a thickener, a surfactant, an optical brightening agent, a coloring pigment, a coloring dye. , A flow improver, an antistatic agent and the like can be appropriately selected and added.

As a method for forming the cast coating layer,
The above coating solution is applied so that the dry coating amount is ² to 30 g / m ² , and while the coating layer is in a wet state, it is pressed against the heated mirror-finished drum surface and dried to increase the strength. A method (cast method) for expressing a glossy and flat surface is used. As a casting method used, a known method such as a wet method, a rewetting method or a gelling method may be appropriately used. In order to increase the surface smoothness of the release paper, the gelling method is particularly preferable.

The coating method for obtaining the cast coating layer is not particularly limited, and a general coating method such as a blade coater, a roll coater, a reverse roll coater, an air knife coater, a die coater, a bar coater or a gravure coater. One-sided or double-sided coating is performed by an on-machine or off-machine coater by a known publicly known coating method such as a coater, curtain coater, lip coater and the like.

The support is preferably a neutral high-quality paper or a medium-quality paper which has coating suitability as a coating support and which is produced in the neutral region of pH 6-9. Further, as the raw material pulp, it is preferable to use ECF (chlorine-free bleaching) pulp having a low chlorine content.

By applying solventless silicone to the cast surface of the thus obtained cast coated paper, a release paper for the production of ceramic green sheets can be obtained.

Examples of the solventless silicone for release paper include addition reaction type, ultraviolet ray curable type and electron beam curable type depending on the curing type, but are not particularly limited.

As a method for applying silicone, coating is performed with an offset gravure coater, a multi-stage roll coater or the like. The coating amount is not particularly limited, but is preferably 0.1 to 1.0 g / m ² .

The release liner for producing a ceramic green sheet preferably has a center line average roughness of not more than 1.0 μm and a maximum roughness of not more than 10 μm according to JIS B-0601. This is because when the center line average roughness exceeds 1.0 μm and the maximum roughness exceeds 10 μm, transfer unevenness due to the roughness of protrusions and the like increases on the surface of the obtained ceramic green sheet.

The release paper for the ceramic green sheet manufacturing process has a surface smoothness of 1 defined by the Oken smoothness.
It is preferably 500 seconds or more. When it is less than 1500 seconds, the surface flatness of the obtained ceramic green sheet is deteriorated and the product characteristics are uneven.

As described above, by providing the release paper for the production process of the ceramic green sheet of the present invention, the surface smoothness comparable to that of the film, the coating uniformity of the solvent-based ceramic slurry, and the release property of the ceramic green sheet after drying are excellent. Process release paper can now be put to practical use.

[0040]

EXAMPLES The concrete constitution of the release sheet for producing a ceramic green sheet of the present invention will be described below based on examples. The invention is not limited by these examples. Unless otherwise specified, the composition% and addition% in the examples
And the weight represent% by weight in terms of solid content. In addition, the paper manufactured for all the examples and comparative examples is JIS-P8111.
The paper quality test was performed after the pretreatment according to the above.

(Example 1) 100 parts by weight of kaolin, SB
17 parts by weight of R-type latex, 9 parts by weight of casein, and 1.0 part by weight of funnel oil as a release agent were added and sufficiently mixed with stirring to obtain a coating liquid for casting of 46% by weight. This coating liquid was applied to one side of a neutral paper having a basis weight of 60 g / m ² using ECF pulp so that the dry coating amount was 20 g / m ^2, and immediately after that, a mirror surface drum having a surface temperature of 80 ° C. Pressure contact to the surface,
After drying, the mold was released to obtain cast coated paper. Solvent-free silicone (manufactured by Shin-Etsu Silicone Co., Ltd .: trade name KNS-320A) was applied to one surface of the cast coated paper in a dry coating amount of 0.3.
Coating was performed so as to be g / m ^2, and a release sheet for producing a green sheet was obtained.

(Example 2) A release paper for producing a green sheet was obtained in the same manner as in Example 1 except that the dry coating amount of the casting coating liquid was adjusted to 10 g / m ² . .

Example 3 A release sheet for producing a green sheet was obtained in the same manner as in Example 1 except that the dry coating amount of the solventless silicone was changed to 0.6 g / m ^2. It was

Example 4 Kaolin 1 in Example 1
00 parts by weight, SBR latex 17 parts by weight, casein
Add 9 parts by weight and 1.0 part by weight of funnel oil as a release agent
And mix thoroughly with stirring to a 46 wt% liquid 60 g / m 2 basis weight
^Two20g / m dry coating amount on one side of neutral paper ^TwoBecomes
After coating, 10% calcium formate as a gelling agent
After gelation treatment with an aqueous solution, the coating layer is exposed while it is in a wet state.
Mold release after pressure contact with mirror surface drum surface with surface temperature of 100 ° C, drying
And the same method as in Example 1 except that cast coated paper was obtained.
Thus, a release sheet for producing a green sheet was obtained.

Example 5 Kaolin 1 in Example 1
00 parts by weight, SBR latex 17 parts by weight, casein
Add 9 parts by weight and 1.0 part by weight of funnel oil as a release agent
And mix thoroughly with stirring to a 46 wt% liquid 60 g / m 2 basis weight
^Two20g / m dry coating amount on one side of neutral paper ^TwoBecomes
After coating, calcium formate 3% water as rewetting liquid
Re-wet with solution and surface while coating is wet
Pressed onto the mirror drum surface at a temperature of 100 ° C, dried, and then released.
And the same method as in Example 1 except that a cast coated paper was obtained.
A release sheet for producing a green sheet was obtained.

Comparative Example 1 Green was produced in the same manner as in Example 1 except that an aqueous emulsion type silicone (manufactured by Shin-Etsu Silicone Co., Ltd .: trade name X-52-195) was used in place of the solventless silicone in Example 1. A sheet release process release paper was obtained.

(Comparative Example 2) A release sheet for producing a green sheet was obtained in the same manner as in Example 1 except that the cast coated paper in Example 1 was replaced with a neutral paper having a basis weight of 60 g / m ^2. It was

Comparative Example 3 In Comparative Example 2, the basis weight is 60 g.
/ M ² of neutral paper with polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd .: trade name Gohsenal T350) 5% by weight solution so that the dry coating amount becomes 1 g / m ² .
A release sheet for producing a green sheet was obtained in the same manner as in Comparative Example 2 except that solvent-free silicone (manufactured by Shin-Etsu Silicone Co., Ltd .: trade name KNS-320A) was coated on the surface coated with polyvinyl alcohol.

Comparative Example 4 A release sheet for producing a green sheet was obtained in the same manner as in Comparative Example 3 except that the dry coating amount of polyvinyl alcohol in Comparative Example 3 was set to 3 g / m ² .

Comparative Example 5 Green was prepared in the same manner as in Comparative Example 2 except that an aqueous emulsion type silicone (manufactured by Shin-Etsu Silicone Co., Ltd .: trade name X-52-195) was used in place of the solventless silicone in Comparative Example 2. A sheet release process release paper was obtained.

Table 1 summarizes the manufacturing conditions of the release sheet for the green sheet manufacturing process in the examples and comparative examples.

[Table 1]

The cast coated paper and the release sheet for producing the green sheet were evaluated as follows. (Surface smoothness) The surface smoothness of the release sheet for the green sheet production was evaluated by obtaining the Oken type smoothness. This affects the surface smoothness of the ceramic green sheet. It is preferably 1500 seconds or more. (Surface Roughness) The surface roughness of the release sheet for the green sheet manufacturing process was evaluated according to JIS B-0601. This means that when the thickness of the green sheet is as thin as 5 to 10 μm, even a protrusion of several μm affects quality problems. (Ceramic coatability) The ceramic coatability was evaluated by visually observing the presence or absence of scratches and cissing on the coated surface. ◯ is good, and x is bad. As the ceramic slurry, a solvent-based ceramic slurry containing barium titanate, barium zirconate, an acrylic binder, toluene and ethanol was used. (Ceramic releasability) For the releasability of ceramics, the degree of peeling of the ceramic film from the process paper was evaluated after coating and drying. ◯ is good, and x is bad.

The evaluation results are shown in Table 2.

[Table 2]

The cast coated papers of Examples 1 to 5 satisfy the conditions that the release liner for producing green sheets has a center line average roughness of 1.0 μm or less and a maximum roughness of 10 μm or less. The surface smoothness of the release sheet for producing the green sheet, the ceramic coatability and the ceramic release property were excellent. In addition, when the ceramic slurry was applied, it had excellent dimensional stability, sufficient solvent resistance (toluene alcohol property), and the ceramic green sheet had surface smoothness.

As the casting method, not only the wet method of Examples 1 to 3 but also the gelling method and the rewetting method were found to be effective in Examples 4 and 5. In particular, Example 4 using the gelation method has excellent surface smoothness and small surface roughness.

On the other hand, in Comparative Example 1, instead of the solventless silicone used in Example 1, an aqueous emulsion silicone was applied. The release sheet for the green sheet production process satisfied the conditions that the center line average roughness of the surface was 1.0 μm or less and the maximum roughness was 10 μm or less, but the flatness was a little poor and the ceramic coating was applied. And the ceramic releasability were both poor.

In Comparative Example 2, solventless silicone was applied without applying the coating liquid. Therefore, the surface of the release sheet for producing the green sheet does not satisfy the conditions that the center line average roughness is 1.0 μm or less and the maximum roughness is 10 μm or less, and the release sheet for producing the green sheet has a flat surface. The smoothness, ceramic coatability and ceramic peelability were poor. Therefore, it is necessary not only to apply the solventless silicone but also to form a cast coating layer that satisfies the above conditions.

In Comparative Examples 3 and 4, polyvinyl alcohol was applied instead of the coating liquid for casting, and then solventless silicone was applied. The surface of the paper coated with polyvinyl alcohol does not satisfy the conditions that the center line average roughness is 1.0 μm or less and the maximum roughness is 10 μm or less, and the release paper for the ceramic green sheet manufacturing process has flat smoothness, At least one of the ceramic coatability and ceramic peelability was poor.

In Comparative Example 5, the aqueous emulsion silicone was applied without applying the application liquid. The surface of the paper coated with the aqueous emulsion silicone has a center line average roughness of 1.0 μm or less and a maximum roughness of 10 μm.
The release paper that does not satisfy the following conditions, the ceramic green sheet manufacturing process, has a flat surface smoothness, a ceramic coatability,
The ceramic releasability was poor.

The release papers for producing the ceramic green sheets of Examples 1 to 5 have a uniform thickness, have an appropriate level of release performance, and can be repeatedly used. Without
Since the release performance is uniform and the ceramic is a solvent-based slurry, the release-treated surface has solvent resistance, good surface smoothness, no foreign matter, paper dust, dust, etc. Therefore, the process release paper having the characteristics of can be put to practical use.

[0061]

According to the invention described in claim 1, it is possible to make a PET or OPP-based process release film, which is currently used as a process base material for producing a ceramic green sheet, into a paper base. It was

According to the second aspect of the present invention, there is provided a process release paper for producing a ceramic green sheet, which is suitable when the solvent-based ceramic slurry contains barium titanate, barium zirconate, an acrylic binder, toluene and ethanol. Could be provided.

According to the third aspect of the present invention, by providing a coating amount of solvent-free silicone, a process release paper for producing a ceramic green sheet, in which ceramic coatability and ceramic releasability are stably obtained, is provided. I was able to.

According to the invention as defined in claim 4, JISB-06 of the surface of the release paper for the production process of the ceramic green sheet is used.
By defining the centerline average roughness and the maximum roughness of 01, it was possible to provide a release sheet for producing a ceramic green sheet in which surface unevenness due to transfer on the surface of the green sheet was suppressed.

According to the invention of claim 5, the process for producing a ceramic green sheet is capable of maintaining the smoothness of the surface of the green sheet above a certain level by defining the surface smoothness of the release paper. A release paper could be provided.

According to the sixth aspect of the invention, the support is EC
By using F pulp, it was possible to provide a release sheet for producing a ceramic green sheet that has a low impact on the environment.

According to the invention described in claim 7, it is possible to provide the most suitable method for producing the release paper for the step of producing the ceramic green sheet according to the present invention.

According to the eighth aspect of the present invention, it is possible to provide a method for producing a release sheet for a ceramic green sheet, which is excellent in surface smoothness and has a small surface roughness.

Continued front page    F-term (reference) 4G052 DB00                 4L055 AB20 AG27 AG63 AG76 AG86                       AG89 AG97 AH02 AH37 AH38                       AJ01 BE08 EA12 EA14 EA19                       FA14 FA30 GA20 GA43

Claims (8)

[Claims] 1. A process release paper for forming a ceramic green sheet by coating a solvent-based ceramic slurry and then curing it, the process release paper being cast coated on a support of the process release paper. A layer is formed, the cast coating layer contains neither calcium carbonate nor sodium salt, and the cast coating layer is formed by coating a solventless silicone on the surface of the cast coating layer. Release paper for manufacturing ceramic green sheets. 2. The release paper for producing a ceramic green sheet according to claim 1, wherein the solvent-based ceramic slurry contains barium titanate, barium zirconate, an acrylic binder, toluene and ethanol. 3. The cast coating layer comprises solventless silicone as a dry coating amount of 0.1 on the surface of the cast coating layer.
^{2. The} coating composition of g / m ² or more is formed.
Alternatively, the release paper for producing a ceramic green sheet according to the item 2. 4. The process release paper has a center line average roughness of 1.0 according to JIS B-0601 on the surface of the process release paper.
The release paper for producing a ceramic green sheet according to claim 1, 2 or 3, wherein the release paper has a maximum roughness of 10 µm or less and a maximum roughness of 10 µm or less. 5. The release paper for process has a surface smoothness of 1500 seconds or more as defined by the Oken type smoothness, which is 1500 seconds or more. Release paper for the production process of the described ceramic green sheet. 6. The process release paper for producing a ceramic green sheet according to claim 1, wherein the support contains ECF (chlorine-free bleaching) pulp. 7. A process release paper manufacturing method for forming a ceramic green sheet by coating a solvent-based ceramic slurry and then curing it, which comprises calcium carbonate and sodium salt on a support of the process release paper. After forming a coating layer by coating a coating liquid for casting which does not contain any of the above, while the coating layer is in a wet state, it is pressed against the mirror surface drum surface heated, dried, and then released to cast. After forming the coated paper,
A process for producing a ceramic green sheet, characterized in that a solvent-free silicone is applied to the surface of the cast coated paper. 8. The method for producing a release sheet for producing a ceramic green sheet according to claim 7, wherein a casting coating solution is applied on a support of the release sheet to form a coating layer, Immediately press-contact the heated specular drum surface, dry it, and then release it, or after gelling, press-contact the heated specular drum surface while the coating layer is in a wet state, dry it, and release it. Or after rewetting,
8. The peeling process for producing a ceramic green sheet according to claim 7, wherein a cast coated paper is formed by press-contacting with a mirror surface drum surface heated while the coating layer is in a wet state, drying, and then releasing from the mold. Paper manufacturing method.