JP2002178316A - Carrier film for molding ceramic sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carrier film for molding a ceramic sheet reducing the unevenness of the peel surface of the ceramic sheet after peeled from a release layer, making the smoothness of the peel surface of the ceramic sheet after peeled from the release layer of the carrier film excellent and preventing the mutual adhesion and blocking when the carrier film for molding the ceramic sheet are laminated in a roll form or a flat plate form to be preserved. SOLUTION: The release layer containing curable silicone as a main constituent is provided on one surface of a polyester film and the difference between the dynamic hardness DH (A) of the ceramic sheet laminated on the surface of the release layer and the dynamic hardness DH (B) of the release layer is within a range of formula (1): |DH (A)-DH (B)|<=20 (gf/μm2) and the coefficient of friction (Fμa) of the surface of the release layer is within a range of formula (2): Fμa>0.3 and the coefficient of friction (Fμb) of the other surface of the polyester film is within a range of formula (3): Fμb<=0.3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carrier film for forming a ceramic sheet, and more particularly, to the releasability of the ceramic sheet when the ceramic sheet is peeled off from the surface of the release layer of the carrier film and the release of the ceramic sheet. The present invention relates to a ceramic sheet molding carrier film having excellent release surface smoothness.

[0002]

2. Description of the Related Art In recent years, electronic devices such as portable telephones and personal computers have been becoming increasingly lightweight and compact. As a result, the size and capacity of electronic components used have been increasing, and the development competition has been intensified. Among them, the technical progress of capacitors, especially multilayer ceramic capacitors, is phenomenal. This is due to the development of multilayer ceramic capacitors suitable for miniaturization and large-capacity, which could not be obtained by conventional capacitors, by the technology of thinning and multi-layering the dielectric layer and the conductor layer.
For this reason, demand for replacement with other capacitors is expected, and further expansion in other applications will be great in the future.

Generally, a ceramic fired sheet used for a multilayer ceramic capacitor is formed by applying ceramic slurry (slurry) on a carrier film to a certain thickness, drying and then peeling off the carrier film to obtain a ceramic sheet. It can be obtained by firing the sheet.

[0004] The carrier film used for producing the ceramic sheet by the above method is generally subjected to a mold release treatment in order to smoothly peel the ceramic sheet. However, as the size of the capacitor is reduced and its capacity is increased, it is necessary to stack many ceramic fired sheets having a smaller thickness. Therefore, it is necessary to form the ceramic sheet as a raw material into a thinner thickness.

[0005]

When the ceramic fired sheet required in the market becomes thinner, the ceramic sheet as a raw material thereof becomes thinner. Therefore, in order to reduce the binder ratio of the ceramic slurry when coating the carrier sheet, There is a tendency that a large force is required for peeling the ceramic sheet, which results in poor peeling or tearing. Further, after the ceramic slurry is applied and dried, the ceramic sheet does not shrink in accordance with the shrinkage of the carrier film for forming a ceramic sheet as before, and the two are displaced. Therefore, since the ceramic sheet molding carrier film shrinks greatly after drying the ceramic sheet, there is a problem that the ceramic sheet is curled, cannot withstand shrinkage, and floats.

[0006] For this reason, the light release properties of the carrier film have come to be preferred. Also, by making the ceramic sheet thinner, when the ceramic sheet is peeled off, the unevenness is transferred to the ceramic peeled surface due to the influence of the unevenness of the release layer surface of the carrier film,
The surface unevenness of the release layer has been required to be small.

However, if the surface unevenness of the release layer is small, when the carrier film before use is stored in the form of a roll, adhesion blocking occurs, the slipperiness is poor when unwinding the ceramic coating, and the film partially hunts. . Therefore, abrasion occurs on the surface of the release layer, or the thickness of the ceramic sheet fluctuates due to vibration caused by hunting,
There was a problem.

[0008] The present invention solves the above-mentioned problems of the conventional carrier film for forming a ceramic sheet, and in the carrier film for forming a ceramic sheet, the peeling surface of the ceramic sheet after peeling from the release layer is small, The releasability of the ceramic sheet and the smoothness of the release surface of the ceramic sheet after peeling from the release layer of the carrier film for forming a ceramic sheet are excellent, and the carrier film for forming a ceramic sheet is laminated in a roll shape or a plate shape. An object of the present invention is to provide a carrier film for forming a ceramic sheet, which does not cause close adhesion blocking when stored.

[0009]

Means for Solving the Problems To achieve the above object, the carrier film for forming a ceramic sheet of the present invention is provided with a release layer mainly composed of curable silicone on one surface of a polyester film. Dynamic DH of ceramic sheet laminated on mold layer surface
The difference between (A) and the dynamic hardness DH (B) of the release layer is within the range of the following equation (1), and the friction coefficient (Fμa) of the surface of the release layer and the friction coefficient of the other surface of the polyester film are shown. (Fμb) is in the range of the following formulas (2) and (3), respectively. | DH (A) -DH (B) | ≦ 20 (gf / μm ² ) (1) Fμa> 0.3 (2) Fμb ≦ 0.3 (3)

In the carrier film for forming a ceramic sheet of the present invention having the above-described structure, the peeling surface of the ceramic sheet after peeling from the release layer has small irregularities, the releasability of the ceramic sheet and the carrier film for forming a ceramic sheet. Excellent in the smoothness of the peeled surface of the ceramic sheet after peeling after peeling from the release layer, and when the carrier film for forming a ceramic sheet is laminated and stored in a roll shape or a flat shape, it is closely blocked with each other. There is no.

Further, the carrier film for forming a ceramic sheet according to the present invention is provided with a release layer mainly composed of curable silicone on both sides of a polyester film, and a ceramic sheet laminated on the surface of the release layer. Dynamic hardness DH (A) and dynamic hardness D of the release layer
The difference from H (B) is in the range of the following equation (1), and the friction coefficient (Fμa) of the surface of the release layer is in the range of the following equation (2). | DH (A) −DH (B) | ≦ 20 (gf / μm ² ) (1) Fμa> 0.3 (2)

The carrier film for forming a ceramic sheet of the present invention having the above-mentioned structure has a small unevenness on the peeling surface of the ceramic sheet after peeling from the release layer, and has a releasability of the ceramic sheet and a carrier film for forming the ceramic sheet. Excellent in the smoothness of the peeled surface of the ceramic sheet after peeling after peeling from the release layer, and when the carrier film for forming a ceramic sheet is laminated and stored in a roll shape or a flat shape, it is closely blocked with each other. There is no.

In this case, the carrier film for forming a ceramic sheet may be a ceramic sheet having a thickness of 1 to 5 μm.

Further, in this case, the polyester film can be at least one film selected from a polyethylene terephthalate film, a polyethylene-2,6-naphthalate film and a polytetramethylene terephthalate.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the carrier film for forming a ceramic sheet according to the present invention will be described.

According to the present invention, there is provided a polyester film provided with a release layer mainly composed of curable silicone on one or both surfaces thereof, wherein the release layer mainly composed of curable silicone has small irregularities. Carrier film for forming a ceramic sheet in which the unevenness of the ceramic peeling surface during the production of the ceramic sheet is small, and the difference between the dynamic hardness of the release layer and the dynamic hardness of the ceramic sheet laminated on the surface of the release layer is within a specific range. And the surface of a release layer formed on one surface of the polyester film (both surfaces when both surfaces are release layers) and the other surface of the polyester film. Eliminate hunting when unwinding a carrier film for forming a ceramic sheet having a specific coefficient of friction in a specific range It has been found.

In the present invention, a polyester film is used as a base film of a carrier film for forming a ceramic sheet. In particular, a biaxially stretched polyester film is preferable because of its excellent mechanical strength, and the polyester constituting the polyester film is composed of an aromatic dibasic acid component such as terephthalic acid and 2,6-naphthalenedicarboxylic acid and a diol component. For example, a crystalline linear saturated polyester composed of ethylene glycol, diethylene glycol, tetramethylene glycol, or the like is preferable, and examples thereof include polyethylene terephthalate, polyethylene-2,6-naphthalate, and polytetramethylene terephthalate. . Organic or inorganic fine particles can be added to the polyester in order to improve the handleability and slipperiness of the film. In particular, it is preferable to contain fine particles having an average particle diameter of 0.01 to 10 μm at a ratio of 0.005 to 5% by weight.

The polyester film used in the present invention can be produced by a conventionally known method. For example, an unstretched film can be obtained by extruding a molten polyester into a molten film by an extruder and cooling by a rotary cooling drum, and uniaxially stretching the unstretched film in a longitudinal direction or a transverse direction. A stretched film can be obtained. Further, the biaxially stretched film is a method of sequentially biaxially stretching a uniaxially stretched film stretched in a longitudinal direction or a transverse direction in a transverse direction or a longitudinal direction, or a method of simultaneously biaxially stretching an unstretched film in a longitudinal direction and a transverse direction. Obtainable. The above stretching temperature is preferably set to be equal to or higher than the secondary transition point (Tg) of the polyester. In the case of a biaxially stretched film, 1.1 to 8 in each direction.
It is preferable that the stretching ratio is 2 times, especially 2 to 6 times. As the thickness of the polyester film, for example, 2 to 30
It is preferably 0 μm, particularly preferably 10 to 125 μm.

The carrier film for forming a ceramic sheet of the present invention is provided with a release layer mainly composed of curable silicone on one or both surfaces of a polyester film. The coefficient of friction (Fμa) of the surface of the release layer of the carrier film for forming a ceramic sheet must exceed 0.3, and preferably exceeds 0.3 and 0.5.
It is as follows. If this value is 0.3 or less, the ceramic sheet peeling surface will have irregularities. The friction coefficient (Fμb) of the other surface of the polyester film forming the carrier film for forming a ceramic sheet must be 0.3 or less, preferably 0.1 to 0.3. If this value is 0.
If it exceeds 5, adhesion blocking occurs with the surface of the release layer, and problems such as the appearance of acne-like irregularities on the surface of the release layer when the roll-shaped film is unwound occur.

Further, a release layer mainly composed of curable silicone is provided on one or both surfaces of the polyester film, and the dynamic hardness DH (A) of the ceramic sheet laminated on the surface of the release layer is determined. One of the requirements is that the difference between the release layer and the dynamic hardness DH (B) is 20 (gf / μm ² ) or less. When the absolute value of the difference in the dynamic hardness exceeds 20 (gf / μm ² ), the peeling performance of the ceramic sheet in the peeling step at the time of the production of the ceramic sheet as described below decreases, and the thin layer, particularly the thickness of 1 to 5 μm In the case of manufacturing the ceramic sheet described above, there are many problems such as tearing of the ceramic sheet and peeling failure at the time of peeling, and a decrease in yield.

When the difference between the dynamic hardness DH (A) of the ceramic sheet laminated on the surface of the release layer and the dynamic hardness DH (B) of the release layer is within the above range,
Even when the carrier film for forming a ceramic sheet is stored in the form of a roll, close contact blocking does not occur due to the winding pressure. Therefore, the irregularities on the back of the carrier film for forming the ceramic sheet are not transferred to the release layer, and the irregularities on the surface of the release layer do not become large. Since it can be easily peeled, a ceramic sheet having a smooth peeled surface can be obtained.

In the evaluation of the releasability on a hard surface such as a ceramic sheet or the like, a clear peeling force value cannot be obtained by a commonly used pressure-sensitive adhesive peeling evaluation method. That is, when the ceramic sheet is hard or the thickness of the ceramic sheet is small, the effect of the viscosity of the ceramic sheet layer is hardly observed when the ceramic sheet layer is peeled off. It is preferable to harden the curable silicone which is a component of the above.

The peeling behavior at the interface between the ceramic sheet and the release layer of the carrier film for forming a ceramic sheet is different from the peeling behavior at the interface between a normal adhesive sheet and the release layer of the carrier film for forming a ceramic sheet. That is, in the case of peeling of the interface between the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet and the release layer of the ceramic sheet forming carrier film, the cohesive energy at the interface becomes dominant. On the other hand, in the case of peeling at the interface between the hard ceramic sheet and the release layer of the carrier film for forming a ceramic sheet, when the release layer is hard, deformation of the release layer at the time of peeling is small, and as a result, the peeling force is low. Become smaller. When the release layer is soft, the release layer is greatly deformed at the time of peeling, and as a result, the peeling force is increased.

Therefore, the peeling behavior between the hard ceramic sheet and the release layer of the carrier film for forming the hard ceramic sheet is not an interfacial peeling force like the peeling between the pressure-sensitive adhesive sheet and the release layer of the ordinary release film, It is considered that it is governed by the interfacial shear force.

The release layer of the carrier film for forming a ceramic sheet is required to be lightly peeled off as hard as a ceramic thin film. Therefore, the release layer needs to be a resin layer having a certain degree of hardness. For this reason, in order to achieve appropriate light releasability, it is preferable that the dynamic hardness of the release layer and the dynamic hardness of the ceramic sheet laminated on the surface of the release layer have the same value.

In order to make the absolute value | A−B | of the dynamic hardness difference equal to or less than 20 gf / μm ² , the hardness of the release layer of the carrier film for forming a ceramic sheet according to the hardness of the ceramic sheet. It is necessary to design.

For example, the ceramic sheet is an unsintered sheet composed of ceramic particles (barium titanate, alumina, aluminum nitride, etc.) and a binder (polyvinyl butyral, polyvinyl alcohol, etc.). When the amount ratio (weight ratio) is large or when the thickness of the ceramic sheet is large, the dynamic hardness of the ceramic sheet when the ceramic sheet is laminated on the surface of the release layer of the carrier film for forming a ceramic sheet becomes small. Further, the dispersibility of the ceramic particles in the ceramic slurry also affects the dynamic hardness of the ceramic sheet. If the dispersibility of the ceramic particles during the preparation of the ceramic slurry is insufficient, the dynamic hardness of the ceramic sheet decreases.

When peeling a ceramic sheet having a small hardness as described above, it is necessary to reduce the dynamic hardness of a release layer containing a curable silicone as a main component. 2) reducing the content of cross-linking groups introduced into the curable silicone, 3) using a curable silicone having a linear molecular structure, etc. can do. It is also effective to increase the thickness of the release layer of the ceramic sheet molding carrier film.

When the content ratio (weight ratio) of the binder to the ceramic particles is small, or when the thickness of the ceramic sheet is small, when the ceramic sheet is laminated on the release layer surface of the ceramic film forming carrier film. The hardness of the ceramic sheet increases.

When a ceramic sheet having a large dynamic hardness as described above is peeled off, it is necessary to increase the dynamic hardness of a release layer containing curable silicone as a main component. It is necessary to adjust the content of hydrophobic groups to be introduced into the silicone, but this can be achieved by increasing the crosslink density of the curable silicone by, for example, increasing the content of crosslinking groups introduced into the curable silicone. can do.

If the thickness of the release layer containing a curable silicone as a main component is uniform on the polyester film surface, the thinner the thickness, the larger the crosslinking density even with a certain curing energy. By making it as small as possible, the hardness of the release layer can be increased.
Further, the dynamic hardness of the release layer may be increased by increasing the mechanical strength of the polyester film.

Further, the dynamic hardness can be controlled also by the curing conditions of the release layer. For example, when active energy ray-curable silicone such as ultraviolet ray or electron beam-curable silicone is used as a component of the release layer. The higher the temperature and the amount of irradiation of active energy rays, the higher the crosslinking density of the ultraviolet ray or electron beam curable silicone constituting the release layer and the higher the dynamic hardness of the release layer.

If the release layer is smooth, a ceramic sheet having a smooth surface can be obtained after the ceramic sheet is peeled off. However, if the back surface of the release layer is similarly smooth, ceramic ceramic is applied. When the carrier film for forming a ceramic sheet is unwound, slipperiness is poor.
For this reason, the back surface of the ceramic sheet forming carrier film is provided with a certain degree of unevenness on the surface so as to have a slipperiness, suppress vibration caused by hunting or the like, and produce a ceramic sheet having a uniform thickness.

In the step of coating and curing the curable silicone on one or both surfaces of the polyester film, the release layer may be formed by a known heat curing or active energy ray curing method. Can be.

The curable silicone is not particularly restricted but includes, for example, addition reaction systems such as solvent addition type and solventless addition type, and condensation reaction systems such as solvent condensation type and solventless condensation type. Any curing reaction type such as an active energy ray curing system such as a solvent ultraviolet curing type, a solventless ultraviolet curing type, and a solventless electron beam curing type can be suitably used. These can be used alone or in combination of two or more.

As the addition reaction type silicone, for example, polydimethylsiloxane having a vinyl group introduced into a terminal and hydrogensilane are reacted using a platinum catalyst,
One that forms a coating film by forming a three-dimensional crosslinked structure is exemplified.

As the silicone of the condensation reaction system, a silanol group (Si—OH group) in a base silicone polymer and a functional group of a cross-linking agent (eg, terminal —OH group) under an organotin catalyst (eg, an organotin acylate catalyst) are used. Dehydrocondensation between a polydimethylsiloxane having the formula (i) and a polydimethylsiloxane having a -H group at the terminal (hydrogensilane) to form a siloxane bond (Si-O-Si), thereby forming a crosslink; One that forms a three-dimensional crosslinked structure may be mentioned.

As the active energy ray-curable silicone, a UV-curable or electron beam-curable silicone is typical. For example, the most basic type is 1)
Siloxane containing alkenyl group and mercapto group,
A radical addition type in which a photopolymerization initiator is added and a crosslinking reaction is performed,
2) A radical polymerization type in which a photopolymerization initiator is added to a siloxane containing a methacrylic group or an acrylic group and cured by radical polymerization; 3) An addition reaction type in which vinylsiloxane is subjected to a hydrosilylation reaction in the presence of a platinum-based catalyst; To decompose the onium salt photoinitiator to generate a Bronsted acid, and then cleave the epoxy group with this to crosslink to form a cationic polymerization type. Above all, UV cationically curable silicones are particularly suitable because they have an epoxy group as a functional group and have excellent adhesion to a corona-treated film. In the case of an electron beam-curable silicone, since an electron beam has higher energy than ultraviolet rays, a radical crosslinking reaction occurs without using an initiator unlike the ultraviolet ray-curable silicone.

In the present invention, specific examples of the silicone-based release agent used to form a release layer containing a curable silicone as a main component include known curing type release agents capable of forming a layer having releasability. Any type of silicone can be used, but it is preferable to use a light release type cured silicone.

As a specific example, in the case of ultraviolet-curable silicone, silicone TPR650 manufactured by Toshiba Silicone Co., Ltd.
0, TPR6501, UV9300, UV9315, U
V9425, XS56-A2775, XS56-A29
82, UV9430, silicone BY24-535, BY24-542, B manufactured by Dow Corning Toray Silicone Co., Ltd.
Silicone X-62-7296, X-62- manufactured by Shin-Etsu Chemical Co., Ltd. such as Y24-551A / B, BY24-538
7305, KS-5504, KS-5505, KS-5
514, X-62-5039, X-62-5040, K
NS-5100, X-62-7028, KNS-530
0, X-62-7540, X-62-7192 and the like.

Examples of the thermosetting silicone include silicone KS-718 and KS-718 manufactured by Shin-Etsu Chemical Co., Ltd.
708A, KS-774, KS-8300, KS-77
5, KS-778, KS-779H, KS-847H,
KS-847, KS-776, X-62-2422, X
-62-2461, KS-3600, KS-856, etc. Dow Corning Asia Ltd. silicone DKQ3
-202, DKQ3-203, DKQ3-204, DK
Q3-205, DKQ3-210, silicone SRX-357, SRX-2 manufactured by Toray Dow Corning Silicone Co., Ltd.
11, SREX211, SP7243S, etc., silicone TPR-6700, TPR-67 manufactured by Toshiba Silicone Co., Ltd.
01, TPR-6721, TPR-6720 and the like.

In the present invention, there is no particular limitation on the method of providing a release layer mainly composed of curable silicone on the surface of the polyester film. For example, 1) a method in which solvent-free curable silicone is applied to at least one surface of a polyester film and then cured by irradiating active energy rays, or heat-cured. 2) The curable silicone is dissolved or dissolved in a solvent. After the dispersion is applied to a polyester film, the solvent is dried and removed, and then cured by irradiating with an active energy ray, or thermally cured. Examples of the coating method include a wire bar coating method, a doctor blade method, a microgravure coating method, a gravure roll coating method, a reverse roll coating method, an air knife coating method, a rod coating method, a die coating method, a kiss coating method, a reverse kiss coating method, An impregnation method, a curtain coating method, a spray coating method, or the like can be applied alone or in combination. Curing conditions for the curable silicone and drying conditions for the solvent may be appropriately selected depending on the type of the curable silicone to be used, the thickness of the release layer, the size of the carrier film for forming a ceramic sheet, and the like.

The coating amount of the curable silicone is usually about 1 to 20 g / m ² , preferably about ² to 15 g / m ² . The thickness of the release layer containing curable silicone as a main component is 0.01 to 0.01 in a dry state.
It is preferably 0.30 μm, more preferably 0.03 to 0.15 μm. If the thickness is less than 0.01 μm, the release performance is deteriorated, and it is difficult to obtain satisfactory performance. When the ceramic sheet is peeled from the ceramic sheet forming carrier film, a large force is required for the peeling. Or torn. Also, since it is difficult to obtain a uniform release layer, the peeling force tends to partially vary and lack stability. When the thickness is more than 0.30 μm,
It takes time to dry the coating film, which causes not only inconvenience in production, but also inadequate curing of the release layer containing curable silicone as a main component, insufficient backside non-transfer property, blocking and other non-peeling properties. Problems arise and are not preferred.

In the present invention, in order to form a release layer containing curable silicone as a main component, silicone can be used alone or diluted with a solvent. For example, it can be dissolved in an aromatic hydrocarbon such as toluene or xylene, an aliphatic hydrocarbon such as cyclohexane, normal hexane or normal heptane, or an organic solvent such as ethyl acetate or ketone according to the concentration used.

In the present invention, the curing method of the formed curable silicone is as follows. After the silicone solution is applied, the drying temperature of the thermosetting silicone is 100 to 160 ° C.
For about 30 seconds. If the drying temperature exceeds 160 ° C., the flatness is impaired. In the case of ultraviolet-curable silicone, the temperature is preferably about 120 seconds or less and about 30 seconds. If the temperature exceeds 120 ° C., the UV curing catalyst is deactivated and curing does not proceed well during irradiation. Irradiation is 100 to 500 mj / cm in integrated irradiation amount
^It is preferably about ² and more preferably 150 to 500 mj / cm ² . The ultraviolet-curable silicone can be applied to a polyester film and then irradiated with active energy such as ultraviolet light or an electron beam to obtain a cured film.

As a light source used for curing the curable silicone, for example, a high-pressure mercury lamp (ozone, ozoneless), a metal halide lamp, a fusion lamp and the like can be used. The number of lamps used can be appropriately used according to the required integrated irradiation amount. The photocuring wavelength has an absorption range in a short wavelength range of 200 to 300 nm, and irradiation is preferably performed within this range. The evaluation performed in the present invention was measured by the following method.

The ceramic sheet is prepared by first mixing and dispersing ceramic powder such as barium titanate, alumina and aluminum nitride in an aqueous or organic solvent. Ethanol and isopropyl alcohol (I
PA), toluene or the like. Next, polymer binders such as polymethyl methacrylate, polyvinyl acetal, polyvinyl butyral, and polyvinyl alcohol, plasticizers such as phthalate and polyethylene glycol, and dispersants such as glycerin and oleate are added and mixed and dispersed by a high-speed mixer or a ball mill. ,
Next, a filtration treatment (for example, a filter having a pore diameter of 3 μm) is performed, and the obtained ceramic slurry is applied and dried on the release layer surface of the carrier film for forming a ceramic sheet so that the thickness after drying becomes about tens to several tens μm. After that, it can be manufactured by peeling off from the carrier film and winding it up.

Examples of the method of applying the ceramic slurry include a doctor blade method, a microgravure roll method, a reverse roll method, a slot die coater and a blade coater. Specifically, in the case of a double-sided coating, The carrier film is immersed in a container containing ceramic slurry, and excess metal is scraped off with a metal bar or doctor blade during lifting, and leveling is performed so that the thickness becomes uniform. Next, it can be obtained by evaporating the solvent through a dryer. In the case of a single-sided coat, pour the slurry over the running carrier film, scrape off excess slurry with a doctor blade, make it to a certain thickness, dry it into a ceramic sheet, and wind it up with the carrier film. Obtainable.

[0049]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. The properties and physical properties used in the present invention were measured by the following methods.

(1) Dynamic Hardness Shimadzu Dynamic Ultra-Micro Hardness Tester (DUH, manufactured by Shimadzu Corporation)
-201-202), pressing a triangular pyramid with a load of 2 gf against a sample (ceramic sheet or release layer), holding for 2 seconds, and then calculating by the following equation. Dynamic hardness DH
Are the dynamic hardness DH (A) of the ceramic sheet laminated on the surface of the release layer and the dynamic hardness DH of the release layer.
The value of (B) was determined. In addition, each measurement was 1
Performed 0 times and their average was used. The measurement of the dynamic strength of the release layer of the ceramic film forming carrier film may be performed on the release layer before the ceramic layer is provided, or the release layer obtained by peeling the ceramic sheet after the ceramic sheet is provided. You may go to. Dynamic hardness DH = α (P / D ² ) (gf / μm ² ) P (gf): Test load D (μm): Intrusion amount of indenter into sample α: Constant by indenter shape, in case of 115 degree triangular pyramid 37.838

(2) Peelability of ceramic sheet In a solvent (toluene), a ceramic raw material (BaTi
O ₃ , average primary particle size 0.6 μm, manufactured by Fuji Titanium Co., Ltd.) 10
After mixing 0 parts by weight, 10 parts by weight of a binder (polyvinyl butyral, manufactured by Sekisui Chemical Co., Ltd.) and 4 parts by weight of a plasticizer (dioctyl phthalate) to form a paste, a ball mill (ceramic balls having a particle diameter of 10 mm, filling amount) 200
g) for 24 hours to obtain a ceramic slurry.
The above ceramic slurry was coated on the surface of the release layer of the carrier film for forming a ceramic sheet by a doctor blade method so that the dry thickness became 5 μm, and 120 ° C. × 1
And dried to obtain a ceramic sheet. This ceramic sheet was cut to a width of 5 cm and peeled (peeling speed 50
(T-type peeling at 0 mm / min) and evaluated according to the following criteria. The measurement was performed five times. The ceramic sheet was peeled without being torn even once. ..1 (class) The ceramic sheet was partially torn once or more. ··· 2 (class) The ceramic sheet was completely torn or broken once or more. ..3 (grade)

(3) Adhesion blocking A carrier film for forming a ceramic sheet obtained by forming and drying a release layer is sampled into a 10 cm square, and the surface of the release layer of the carrier film and the other of the polyester film forming the carrier film are sampled. Tying the faces of 1
Zero sheets were overlaid. The temperature is 25 ° C and the humidity is 65% RH.
After holding under a load of 300 kg for 10 minutes under the conditions of
The adhesion between the release layer and the back surface of the film was confirmed, and judged based on the following criteria. A: No close contact was observed. ... ◎ B: Adhered, but easily peeled off. ... ○ C: Adhesion occurred and acne occurred on the release layer surface after peeling. ... ×

(4) Coefficient of Friction A sample cut into a size of 8 × 20 cm was affixed on a metal flat table with the measurement surface facing up. Further, a sample cut to 5 × 7 cm was superimposed on the above sample with the measurement surface facing down, a 4.4 kg load was applied thereon, and the sample was pulled at a speed of 200 mm / min, and the slipperiness was confirmed by the following judgment. . The measurement was performed five times. ≦ 0.3 ・ ・ ・ 1 (grade) 0.3-0.5 ・ ・ ・ 2 (grade)> 0.5 ・ ・ ・ 3 (grade)

(5) Smoothness of ceramic peeling surface After the ceramic sheet was peeled, the smoothness of the peeling surface of the ceramic sheet was visually judged according to the following criteria. It was glossy and smooth ... 1 (grade) The unevenness of the release layer was transferred ... 2 (grade) There was unevenness of the particles ... 3 (grade)

(Example 1) Ultraviolet cation-curable silicone (XS56-A1652 manufactured by Toshiba Silicone Co., Ltd.) was dispersed in a solvent (normal hexane) (concentration of 2% by weight), and 1% by weight based on 100% by weight of silicone resin. Bis (alkylphenyl) iodonium hexafluoroantimonate was added as a curing catalyst to produce a silicone coating liquid. Then, using a coater, a thickness of 38 μm,
On one surface (Ra1 surface) of a biaxially stretched polyester film (manufactured by Toyobo Co., Ltd.) having one centerline average roughness (Ra1) of 0.008 μm and the other centerline average roughness (Ra2) of 0.015 μm. Apply the above coating liquid, and dry with a dryer.
After removing the solvent at 30 ° C. for 30 seconds, the solution was passed through an ultraviolet irradiation facility equipped with three high-pressure mercury lamps of 150 W / cm, and the integrated irradiation amount was 30
Irradiation with UV light of 0 mj / cm ² (after drying)
A polyester film having a cured silicone coating of 0.1 g / m ² was obtained. On the surface of the release layer of the carrier film obtained above, a ceramic sheet was provided by laminating ceramic slurry (ceramic raw material / binder = 100/10: weight ratio) so that the thickness after drying became 5 μm. .
Table 1 shows the set conditions and the evaluation of the obtained carrier film for forming a ceramic sheet.

(Example 2) In Example 1, the release layer of the carrier film for forming a ceramic sheet used was as follows. The release layer was prepared by dispersing a thermosetting silicone (KS830 manufactured by Shin-Etsu Chemical Co., Ltd.) in a solvent (toluene) (3% by weight).
Concentration), 100% by weight of silicone resin and 1% by weight of a platinum catalyst were added to prepare a silicone coating liquid, which was applied with a wire bar, dried at 140 ° C. for 30 seconds, and released from a release layer (silicone resin). The weight of the release layer after drying is 0.05 g /
m ² ). The procedure was the same as in Example 1 except that this ceramic sheet molding carrier film was used.
Table 1 shows the set conditions and the evaluation of the obtained carrier film for forming a ceramic sheet.

(Embodiment 3) In the embodiment 2, 38 μm
Thick biaxially oriented polyester film (Toyobo Co., Ltd.)
Example 1 was applied to a surface having a center line average roughness of 0.008 μm.
And an aqueous coating liquid containing particles on the back surface (specifically, a coating liquid in which resin / particles are dispersed in a water / IPA solvent at a weight ratio of 10/1). , 70 ° C
X 30 seconds to dry the center line average roughness to 0.020 μm
Example 2 was the same as Example 2 except for the above. Table 1 shows the set conditions and the evaluation of the obtained carrier film for forming a ceramic sheet.

Example 4 Example 2 was carried out in the same manner as in Example 2, except that the weight of the silicone release layer after drying was 0.5 g / m ² as the carrier film for forming a ceramic sheet. did. Table 1 shows the set conditions and the evaluation of the obtained carrier film for forming a ceramic sheet.
Shown in

(Comparative Example 1) In Example 2, 38 μm
Thickness, the center line average roughness of the release layer forming surface is 0.015 μm
Example 2 was performed except that the biaxially stretched polyester film (manufactured by Toyobo Co., Ltd.) was used. Table 1 shows the set conditions and the evaluation of the obtained carrier film for forming a ceramic sheet.

(Comparative Example 2) The procedure of Example 1 was repeated, except that the integrated irradiation amount of the ultraviolet irradiation was changed to 100 mj / cm ² . Table 1 shows the set conditions and the evaluation of the obtained carrier film for forming a ceramic sheet.

(Comparative Example 3) In Example 2, 38 μm
The thickness and the center line average roughness of the release layer forming surface are 0.008 μm
Example 2 was repeated except that the biaxially stretched polyester film was used. Table 1 shows the set conditions and the evaluation of the obtained carrier film for forming a ceramic sheet.

[0062]

[Table 1]

In Examples 1, 2, and 4, the moderate release property is maintained by setting the absolute value of the difference in dynamic hardness between the release layer and the ceramic sheet to 20 or less, and the surface of the release layer is smoothened. Thereby, the smoothness after ceramic peeling was maintained, and the occurrence of adhesion blocking was eliminated by providing surface irregularities on the back surface. In Example 3, the adhesion blocking could be prevented in the same manner as the base unevenness by providing the surface unevenness with the water-soluble coating liquid on the back surface.

In Comparative Example 1, although a biaxially stretched polyester film having surface irregularities was used, the irregularities of the polyester film were transferred to the ceramic release surface.

In Comparative Example 2, since the amount of ultraviolet rays applied to the silicone coating liquid for forming the release layer was small, the silicone coating solution was not sufficiently cured, and the dynamic hardness was insufficient. .

In Comparative Example 3, since a smooth raw material was used,
Although the smoothness of the ceramic peeled surface was obtained, adhesion blocking occurred during unwinding.

[0067]

According to the carrier film for forming a ceramic sheet of the present invention, the peeling surface of the ceramic sheet after peeling from the release layer has a small unevenness, the releasability of the ceramic sheet and the carrier film for forming the ceramic sheet. The smoothness of the peeled surface of the ceramic sheet after peeling from the release layer is excellent, and when the ceramic film forming carrier film is laminated and stored in a roll shape or a flat shape, there is no mutual blocking.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Harunobu Kuroiwa 2-8-8 Dojimahama, Kita-ku, Osaka-shi Toyobo Co., Ltd. F-term (reference) 4F100 AK41A AK42A AK52B AT00A BA02 GB41 JB12B JL14 4G052 DA02 DB01

Claims (4)

[Claims] 1. A release layer mainly composed of curable silicone is provided on one surface of a polyester film, and the dynamic hardness DH (A) of a ceramic sheet laminated on the surface of the release layer and the dynamic hardness of the release layer Hardness DH (B)
And the friction coefficient (Fμa) of the surface of the release layer and the friction coefficient (Fμb) of the other surface of the polyester film are expressed by the following equations (2) and (3), respectively. The carrier film for forming a ceramic sheet, characterized in that: | DH (A) -DH (B) | ≦ 20 (gf / μm ² ) (1) Fμa> 0.3 (2) Fμb ≦ 0.3 (3) 2. A release layer containing a curable silicone as a main component is provided on both surfaces of a polyester film, and the dynamic hardness DH (A) of a ceramic sheet laminated on the surface of the release layer and the release hardness of the release layer are determined. Dynamic hardness DH
A carrier film for forming a ceramic sheet, wherein the difference from (B) is in the range of the following formula (1), and the friction coefficient (Fμa) of the surface of the release layer is in the range of the following formula (2). | DH (A) −DH (B) | ≦ 20 (gf / μm ² ) (1) Fμa> 0.3 (2) 3. The carrier film for forming a ceramic sheet according to claim 1, wherein the carrier film is a ceramic sheet having a thickness of 1 to 5 μm. 4. The polyester film according to claim 1, wherein the polyester film is at least one film selected from a polyethylene terephthalate film, a polyethylene-2,6-naphthalate film and a polytetramethylene terephthalate. Carrier film for forming ceramic sheets.