JPH10743A - Release film for ceramic sheet production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the efficient manufacturing of ultra-thin ceramic sheet having favorable surface smoothness by a method wherein a silicon-based coat is provided on one side of a plastic film, on the other side of which a resin coat containing the specified amount of the specified particle is provided. SOLUTION: As for a release film used for manufacturing a ceramic sheet for laminated ceramic capacitor or the like, silicone-based coat is provided on one side of a plastic film, on the other side of which a resin coat containing 0.1-10wt.% of particle having the particle diameter of 0.05-4.0μm is provided. In this case, polyethylene terephthalate film, polyethylene-2,6-naphthalate film of the like is preferably used as the plastic film. Further, as for the particle, silicone-based fine particles is employed. Furthermore, the silicone-based coat is obtained by forming the crosslinked structure of silicon through the addition reaction of polyorganosiloxane or the like in the presence of platinum-based catalyst and preferably formed in stripes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a release film used for producing a ceramic sheet.

[0002]

2. Description of the Related Art In recent years, as a carrier film for a process for producing a ceramic sheet for a multilayer ceramic capacitor or the like, a release film in which a heat- or ultraviolet-curable silicone-based film is provided as a release layer on a plastic film is generally used. It is used regularly. Such a release film having a silicone-based film is disclosed in
No. 141553, Japanese Unexamined Patent Publication No. Hei 3-231812,
Japanese Patent Publication No. 4-59207 and Japanese Patent Publication No. 6-2393 are known.

[0003] The ceramic sheet is prepared by dispersing a ceramic powder such as barium titanate or alumina in an aqueous or organic solvent and dispersing a polymer binder such as polymethyl methacrylate, polyvinyl acetal, polyvinyl butyral, and polyvinyl alcohol with a plasticizer and a dispersant. The resulting ceramic slurry is mixed and dispersed by a high-speed mixer or a ball mill, and the obtained ceramic slurry is applied on a release film to a thickness of several hundred μm to several tens μm by a doctor blade method, and dried and wound. Generally manufactured by taking.

In recent years, in order to realize a multilayer ceramic chip capacitor having a small size and a high capacitance, it has been required to reduce the thickness of one ceramic layer and to form a multilayer stack.
For this purpose, a very thin ceramic sheet having a thickness of 20 μm or less is released from the release film accurately and without defects, and a release film having a smoother surface is used. By smoothing the surface of the ceramic sheet and improving the degree of lamination adhesion of the sheet, the capacity of the multilayer ceramic capacitor becomes stable and the withstand voltage defect rate becomes good.

[0005] To this end, it is important that the plastic film used for the release film has uniform thickness, surface smoothness and uniform release force on the release surface. However, the above-mentioned 20 μm
The following very thin ceramic slurry layer is applied with a die coater or the like, dried, and after the release film and the ceramic sheet are co-wound, when the release film and the ceramic sheet are released, the back side of the release surface and There is a problem that the ceramic sheet is blocked and a part of the ceramic sheet falls off, thereby causing a pinhole defect in the ceramic sheet. If the ceramic sheet has such a pinhole defect, the withstand voltage defect rate of the multilayer ceramic capacitor is undesirably increased.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and provides a ceramic sheet for producing a ceramic sheet having good surface smoothness, particularly a thin ceramic sheet having a thickness of 20 μm or less. It is intended to provide a mold film.

[0007]

The object of the present invention is to provide a silicone film on one side of a plastic film,
In addition, particles having a particle diameter of 0.05 to 4.0 μm
This is achieved by a release film for producing a ceramic sheet, which is provided with a resin film containing 1 to 10% by weight.

A feature of the present invention is that a plastic film having a smooth surface has a silicone-based coating layer on one surface and 0.01% particles having a particle size of 0.05 to 4.0 μmφ on the other surface, that is, the back surface.
This is because a resin film containing 10 to 10% by weight is provided, which not only suppresses blocking when a thin ceramic sheet having a thickness of 20 μm or less is produced, but also uses a plastic film having a smoother surface. As a result, the surface smoothness of the ceramic sheet could be improved.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

As the plastic film of the present invention,
For example, synthetic polymer films (including sheets) such as a polypropylene film, a polyester film, and a nylon film can be exemplified. Among them, heat resistance,
Polyethylene terephthalate film, polyethylene-2,6-naphthalate film, and polyethylene-α, β-bis (2-chlorophenoxy) ethane-4,4′-dicarboxylate film, which are excellent in surface properties and the like, are preferable, and in particular, Excellent in mechanical strength and dimensional stability 2
An axially stretched polyethylene terephthalate film, a biaxially stretched polyethylene-2,6-naphthalate film, and a biaxially stretched polyethylene-α, β-bis (2-chlorophenoxy) ethane-4,4′-dicarboxylate film are preferred.

[0011] The surface smoothness of the plastic film is 0.01 to 0.01 at a cut-off value of 0.25 mm for the center line surface roughness (Ra) in order to clarify the features of the present invention.
0.03 μm, preferably in the range of 0.01 to 0.02 μm.

The plastic film constituting the present invention is produced by a conventional method, and in particular, a biaxially oriented polyethylene terephthalate film, a biaxially oriented polyethylene-2,6-naphthalate film, a biaxially oriented polyethylene-α, The film thickness of the β-bis (2-chlorophenoxy) ethane-4,4′-dicarboxylate film is 15 to 350 μm, preferably 20 to 100 μm.
Those having a range of μm are preferably applied in terms of mechanical properties, dimensional stability, heat resistance, price and the like.

The silicone-based coating of the present invention contains a polyorganosiloxane having a structure represented by the following formula (1) as a main component to further clarify the objects and effects of the present invention.

Further, the silicone film is formed by crosslinking a polyorganosiloxane represented by the following formula (1) and an organohydrogenpolysiloxane by an addition reaction in the presence of a platinum-based catalyst represented by chloroplatinic acid. It is generally obtained by forming a structure.

At this time, drying and curing (thermal curing, ultraviolet curing, etc.) of the silicone coating can be performed individually or simultaneously. At the same time, although it depends on the heat resistance (thermal dimensional stability) of the plastic film, it is 80 ° C to 200 ° C, preferably 120 ° C to 18 ° C.
It is desirable to heat at a temperature of 0 ° C. for 15 seconds or more.
Further, the thickness of the silicone-based coating is 0.1% in the thickness after drying.
The range is preferably from 0.5 to 0.5 μm, and more preferably from 0.1 to 0.3 μm.

[0016]

Embedded image (In the formula, R1 represents a methyl group and / or a phenyl group, and Vi represents a vinyl group.) In the present invention, the coating method for forming the silicone-based film is not particularly limited, but is usually benzene, toluene,
Silicone resin in an organic solvent such as aromatic hydrocarbons such as xylene, aliphatic hydrocarbons such as cyclohexane, n-hexane and n-heptane, halogenated hydrocarbons such as perchloroethylene, and ethyl acetate and methyl vinyl ketone. ~ 1
Using a coating solution dissolved at a concentration of 8% by weight, a direct gravure coater, a micro gravure coater, a reverse gravure coater, a direct kiss coater, a reverse kiss coater, a comma coater, a die coater, and a bar-rod type coating device are applied. Obtained by: Among them, it is preferable to use a microgravure coater, a direct kiss coater, or a reverse kiss coater because the uniformity of the thickness of the silicone-based coating is improved and the occurrence of coating unevenness is reduced.

In the present invention, the resin film provided on the back surface of the release surface is at least one selected from non-silicone resins such as polyester, alkyd, polyurethane and epoxy resin, and is resistant to solvents such as toluene. Polyurethane-based resins and alkyd-based resins are particularly preferred in terms of solvent properties and the like.

In the present invention, the coating method for forming the bark film is not particularly limited, but usually, aromatic hydrocarbons such as benzene, toluene and xylene, cyclohexane,
aliphatic hydrocarbons such as n-hexane and n-heptane, halogenated hydrocarbons such as perchloroethylene, ethyl acetate,
A direct gravure coater, a micro gravure coater, a reverse gravure coater, a direct kiss coater, a reverse kiss coater, a comma coater, a die coater using a coating agent in which a resin is dissolved in an organic solvent such as methyl vinyl ketone at a concentration of 1 to 20% by weight. And a bar-rod type coating device.

In the present invention, the particles contained in the resin film include, for example, inorganic particles such as colloidal silica, aluminum oxide, calcium carbonate, and titanium oxide, crosslinked polystyrene-based fine particles, epoxy resin-based fine particles, and acrylic resin-based fine particles. And at least one selected from organic particles such as fluororesin-based fine particles and silicone resin-based fine particles, among which silicone resin-based fine particles having good dispersibility in a resin film are particularly preferable.

Examples of such silicone-based fine particles include "Tospearl" manufactured by Toshiba Silicone Co., Ltd. and "Trefill" manufactured by Toray Dow Corning Silicone Co., Ltd. In the present invention, the particle diameter of particles contained in the silicone-based coating layer and the bark coating layer provided on the back side is 0.0
It is necessary to be in the range of 5 to 4.0 μmφ, preferably in the range of 0.2 to 1.0 μmφ. If this value is less than 0.05 μmφ, preferably less than 0.2 μφ,
It is difficult to obtain a sufficient blocking suppressing effect, which is not preferable. Further, the particle diameter is 4.0 μφ, preferably 1.0 μφ.
When the diameter exceeds φ, the particles easily fall off, which is not preferable.

Further, the content of the particles to be contained in the bark coating layer must be in the range of 0.01 to 10% by weight, preferably in the range of 0.1 to 3% by weight. If this value is less than 0.1% by weight, it is difficult to obtain a sufficient blocking suppressing effect, which is not preferable. On the other hand, if the particle size exceeds 10% by weight, preferably 3% by weight, the particles tend to fall off, and the surface smoothness of the ceramic sheet after releasing is unfavorably deteriorated.

In the present invention, a groove is formed in a gravure roll or the like, and a silicone-based coating material is stripped in a longitudinal direction using a direct gravure coater, a reverse gravure coater, a kiss direct gravure coater, a reverse gravure coater, a microgravure coater, or the like. By coating on a film, a striped silicone-based film can be formed on a plastic film.

Further, the back surface of the release film having the striped silicone film has a particle size of 0.05 to 4.0.
By providing a resin film containing 0.01 to 10% by weight of particles of μmφ, a very thin ceramic sheet having a thickness of about 3 to 10 μm can be manufactured.
Optimum as a release film for manufacturing high-capacity multilayer laminated ceramic chip capacitors.

[0024]

EXAMPLES The present invention will be described specifically with reference to Examples, but the present invention is not limited thereto. The characteristics of the release film were evaluated by the following methods.

(1) Release Property A release film and a polyester adhesive film (31B tape manufactured by Nitto Denko Corporation: 50 mm width) are adhered to each other while being pressed with a 5 kg roller, and left after leaving at 20 ° C. for 20 hours.゜ Measure the peel strength with tensilon. Here, it can be said that if the peeling force is 30 g or less, it is good.

(2) Blocking property of ceramic sheet A ceramic slurry having the following composition was applied on the release layer of the release film by a doctor blade method, dried and solidified, and then the release film and the ceramic sheet were bonded together. 10 sheets in a state, 40 under a load of 20 g / cm ²
And left for 2 weeks. Thereafter, the ceramic sheet was peeled off to obtain a ceramic sheet having a thickness of 15 μm. The ceramic sheet at this time was observed with an optical microscope, and those with a large number of pinholes were rated "X", those with a small number of pinholes were rated "△", and those without any pinholes were rated "○". "

"Composition of Ceramic Slurry" Alumina 53 parts by weight Barium oxide 8 parts by weight Silicon oxide 36 parts by weight Polyvinyl butyral 30 parts by weight Dichloroethane 80 parts by weight (3) Particle-removing property After the resin film surface is rubbed, it is rubbed. When observed with an optical microscope at × 100, × indicates that the particles easily fall off, X indicates that the coating film slightly falls off by rubbing strongly 6 times, ○ indicates that the particles do not fall off even after rubbing strongly 6 times, Those that did not fall off even after rubbing strongly 20 were rated as ◎. ○ If it is above, it can be said that it is good.

Example 1 Biaxially stretched polyester film having a thickness of 50 μm “Lumilar T70” manufactured by Toray Industries, Inc.
On one side of the surface was coated with particles as a non-silicone resin film layer.
A urethane-based resin coating liquid having the following composition A containing 87% by weight was applied using a gravure roll (# 150, oblique line type), dried in a 150 ° C. oven for 10 seconds, and thermally cured to form a film. Further, the following composition B is applied to the back surface of the resin film layer as a thermosetting silicone resin coating agent using a gravure roll (# 200, oblique line type), dried in an oven at 120 ° C. for 15 seconds, and heat cured. Then, a release film was obtained.

The results of the evaluation of the properties of the obtained release film are shown in Table 1. The results show that the release properties, the blocking properties of the ceramic sheet, and the particle detachability of the resin film layer are all good.

“Non-Silicone Resin Coating Composition / Composition A” 1) 10 parts by weight of polyester polyol 2) 1.5 parts by weight of diphenylmethane diisocyanate 3) 0.01 part by weight of dibutyltin dilaurate 4) 30 parts by weight of toluene 5) methyl isobutyl Ketone 15 parts by weight 6) Methyl ethyl ketone 15 parts by weight 7) Silicone fine particles "Tospearl 108 (particle diameter 0.8 μm)" 0.1 parts by weight "Thermosetting silicone resin coating composition B" 1) Shin-Etsu Chemical Co., Ltd. KS847H 10 parts by weight 2) Shin-Etsu Chemical Co., Ltd. PL-8 0.10 parts by weight 3) Toluene 100 parts by weight [Example 2] Particles contained in the non-silicone resin film layer having a particle diameter of 1.0 μmφ. A release film was obtained in the same manner as in [Example 1] except that colloidal silica was used.

The results of the evaluation of the properties of the obtained release film are shown in Table 1. The results show that the release properties, the blocking properties of the ceramic sheet, and the particle detachability of the resin film layer are all good.

Example 3 Except that the content of particles to be contained in the non-silicone resin film layer was set to 4% by weight,
A release film was obtained in the same manner as in [Example 1].

The results of the evaluation of the properties of the obtained release film are shown in Table 1. The results show that the release property, the blocking property of the ceramic sheet, and the particle detachability of the resin film layer are all good.

Example 4 When the following composition B was applied as a heat-curable silicone resin coating material using a gravure roll (# 200, oblique line type), grooves were formed in stripes so as to have a coating width of 200 mm. The provided gravure roll (# 2
00, oblique line type) to obtain a release film in which six stripes each having a coating width of 200 mm in the longitudinal direction were applied by a reverse method.

The results of the evaluation of the properties of the obtained release film are shown in Table 1. The results show that the release properties, the blocking properties of the ceramic sheet, and the particle detachability of the resin film layer are all good.

Further, by slitting the margin portion of the silicone release layer of the stripe type, a release film having a margin portion where the silicone layer is not applied at the end can be obtained. By using the release film, it was possible to produce a ceramic sheet that was thinner than before.

Comparative Example 1 A release film was obtained in the same manner as in Example 1 except that no particles were added to the non-silicone resin film layer.

The results of evaluation of the properties of the obtained release film are shown in Table 1, but the blocking properties of the ceramic sheet are poor.

[Comparative Example 2] Dry silica (Aerosil 20) having a particle size of 0.02 μmφ was coated on the non-silicone resin coating layer.
Except for adding 0), a release film was obtained in the same manner as in [Example 1].

The results of evaluating the properties of the obtained release film are shown in Table 1, but the ceramic sheet is inferior in the blocking property.

Comparative Example 3 A release film was obtained in the same manner as in [Example 1] except that heavy calcium carbonate particles having a particle diameter of 5 μmφ were added to the non-silicone resin film layer.

The results of evaluation of the properties of the obtained release film are shown in Table 1. The results are inferior in the particle detachability.

Comparative Example 4 A release film was obtained in the same manner as in Example 1 except that the content of the particles in the non-silicone resin coating layer was 0.005% by weight.

The results of evaluation of the properties of the obtained release film are shown in Table 1, but the ceramic sheet is inferior in the blocking property.

[Comparative Example 5] [Example 1] except that the content of the particles in the non-silicone resin film layer was changed to 15% by weight.
A release film was obtained in the same manner as described above.

The results of evaluation of the properties of the obtained release film are shown in Table 1. The results are inferior in the particle detachability.

[0047]

[Table 1]

[0048]

As described above, according to the release film of the present invention, a ceramic sheet having few defects such as pinholes can be manufactured. In particular, when a thin ceramic sheet having a thickness of 20 μm or less is produced, the blocking on the back side of the release surface is suppressed, so that it is possible to use a plastic film having a smoother surface. It was possible to provide a release film for producing a ceramic sheet which can improve the productivity of the production of the ceramic sheet and improve the productivity.

Claims (5)

[Claims] 1. A plastic film having a silicone coating on one surface and a particle size of 0.05 to 4.0 μmφ on the other surface.
A release film for producing a ceramic sheet, comprising a resin film containing 0.01 to 10% by weight of particles of 2. The plastic film is at least one selected from polyethylene terephthalate, polyethylene-2,6-naphthalate, and polyethylene-α, β-bis (2-chlorophenoxy) ethane-4,4′-dicarboxylate. The release film for producing a ceramic sheet according to claim 1, wherein: 3. The release film according to claim 1, wherein the particles are silicone-based fine particles. 4. The method according to claim 1, wherein the particles have a particle size of 0.2 to 1.0 μmφ and the content of the particles in the resin film is 0.1 to 3% by weight. The release film for producing a ceramic sheet according to any one of the preceding claims. 5. The release film for producing a ceramic sheet according to claim 1, wherein a silicone-based film is provided in a stripe shape on a plastic film.