JP2009034947A - Mold-releasing film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold-releasing film capable of preventing a sheet pin hole and thickness variation of a sheet during producing the thin ceramic green sheet, excellent in appearance of the green sheet, and excellent in a mold-releasing property. <P>SOLUTION: In the mold-releasing film, thermosetting silicone resin including 0.4-1.8 wt.% of a silicone-glycol copolymer is provided on at least a single surface of a base material film. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a release film in which a base film is provided and a release layer is provided on at least one surface thereof.

  Conventionally, a release film provided with a release layer on the surface of a plastic film is used as a release film such as an adhesive label, an adhesive film, a polarizing film for liquid crystal, or a process film such as a ceramic sheet or a polyvinyl chloride sheet molding. Widely used.

  As a release film for the production of multilayer ceramic capacitors, silicone terephthalate for release paper is used on at least one side of polyethylene terephthalate, which has excellent mechanical strength, heat resistance, thermal dimensional stability and chemical resistance, and is economically advantageous. A carrier film provided with a resin layer is generally used.

  In recent years, multilayer ceramic capacitors have been required to have a thinner and more multilayered ceramic sheet in order to reduce size and increase capacity. The thickness of the current ceramic green sheet is generally used from 5 μm to 10 μm. Further, as a thin ceramic green sheet, a sheet having a thickness of about 1 μm to 5 μm has been developed, and a sheet having a sheet thickness of 1 μm or less has been studied.

  However, when trying to thin the ceramic sheet in this way, to reduce the viscosity of the slurry and make the sheet, to prevent pinholes due to the repellency of the ceramic slurry, to improve the uniform application of the ceramic sheet, It is necessary to improve the wettability of the release film. Further, as the release film, a release film having no change in the peeling force of the surface layer and the core of the product over the entire length of the product roll in the roll is required.

  A general composition of the ceramic slurry is a mixture obtained by dispersing ceramic powder, a binder component, mainly polyvinyl butyral, a plasticizer, and mainly dioctyl phthalate in a solvent (mixed solvent of toluene / alcohol).

  That is, as a release film, in order to obtain a good coating surface and good release properties, the contact angle with an aqueous solvent, that is, pure water is improved, and the release layer to the organic solvent is used to prevent the ceramic sheet from being damaged. It is necessary to control the liberation of some of them.

  For the purpose of obtaining good releasability with respect to the ceramic slurry, a technique for improving the wetting property has been disclosed (see Patent Document 1). Defects are reduced, but when a thin film ceramic sheet is produced, it is difficult to peel off and sheet tearing occurs.

  Conventional release films that are easy to peel off have not been a major problem when the thickness of the ceramic sheet is about 5 μm. However, when the thickness of the ceramic sheet is less than 5 μm, the conventional mold release film has poor wettability between the mold release film surface and the mold release layer, and pinholes are caused by the protrusions on the mold release film surface. There has occurred.

However, the conventional method of improving the wettability of the release film surface and the release layer is difficult to peel off even when the release layer and the ceramic sheet are required to peel off due to occurrence of sheet pinholes, sheet tears, etc. There is a problem that it cannot be used for thin ceramic sheets.
Japanese Patent Laid-Open No. 9-262936

  Therefore, the object of the present invention is to provide a release film that has no sheet pinholes and sheet thickness unevenness, has excellent green sheet appearance, and has excellent releasability when a thin ceramic green sheet of about 1 to 5 μm is manufactured. There is to do.

  The present invention is intended to achieve the above object, and the release film of the present invention contains 0.4 Wt% to 1.8 Wt% of the silicone-glycol copolymer on at least one surface of the base film. A release film provided with a thermosetting silicone resin as a release layer.

  The release film of the present invention can prevent sheet pinholes, sheet tears, sheet thickness unevenness, and scum-like appearance defects that occur when casting a thin green sheet. The release film of the present invention can prevent pinholes, breaks, etc. of the ceramic green sheet, particularly when film protrusions of 1000 nm or more exist.

  In addition, the release film of the present invention is a release film having excellent release properties over the entire length of the product roll, and is suitable as a release film for ceramic capacitors. The release film of the present invention is particularly excellent in peeling properties when peeled when a green sheet for a thin film ceramic capacitor is formed.

  Next, the present invention will be described in detail.

  Hereinafter, the release film of the present invention will be described in detail.

  Examples of the base film of the release film of the present invention include a polyester film, an olefin film, a polycarbonate film, an acrylic film, and a polyacid film, but a polyethylene terephthalate film (PET) having excellent heat resistance and surface characteristics, A polyethylene-2,6-naphthalene dicarboxylate (PEN) film is preferable, and a biaxially stretched polyethylene terephthalate film excellent in mechanical strength and dimensional stability is particularly preferable.

  The base film of the release film of the present invention is preferably a biaxially stretched film, more preferably a biaxially stretched polyester film.

  The biaxially stretched polyester film preferably used in the present invention is, for example, dried polyester film, melted with an extruder, extruded from a die (T-die, I-die, etc.) onto a rotating cooling drum, cooled and unstretched. A film is manufactured, and then the unstretched film is stretched in the longitudinal direction and the transverse direction, and heat-fixed as necessary.

  In addition, the base film of the release film of the present invention may be subjected to corona treatment on the surface of the base film in order to improve the adhesion of the silicone resin for release. Easy adhesion treatment may be used.

  The substrate film thickness of the release film of the present invention is preferably 10 μm to 100 μm, more preferably 25 μm to 50 μm, from the viewpoint of mechanical properties, dimensional stability, and heat resistance.

In the present invention, the base film is preferably a base film having 3/100 cm ² or less coarse protrusions having a diameter of 30 μm or more.

In the present invention, it is preferable to use a base film in which coarse projections having a height of 0.8 μm or more and a diameter of 100 μm or more are 0 pieces / cm ² .

  The release film of the present invention can further improve the defect rate due to sheet pinholes and sheet breakage by controlling the height and size of the coarse protrusions of the base film.

  In the present invention, a thermosetting silicone resin is provided as a release layer on at least one surface of the base film.

  The thermosetting silicone resin used in the present invention is preferably composed mainly of an addition reaction type or condensation polymerization type silicone resin.

  The addition reaction type silicone resin is preferably polydimethylsiloxane containing a terminal vinyl group or polydimethylsiloxane containing a hexenyl group at the terminal. The addition reaction type silicone resin is preferably one that is heat-cured using a platinum catalyst.

  Specific examples of the addition reaction type silicone resin include Shin-Etsu Chemical Co., Ltd. product names KS774, KS778, KS838, 847H, and Toray Dow Corning product names SD7226, SD7223, SRX211 and LTC750A.

  The polycondensation silicone resin is preferably polydimethylsiloxane and hydrogensiloxane containing a hydroxyl group at the terminal. The polycondensation silicone resin is preferably one that is heat-cured using an organotin catalyst.

  As a method for applying these thermosetting silicone resins to a polyester film, a general coating method can be used. For example, a coating method such as gravure coating, gravure reverse coating, lip coating, die coating, micro gravure coating, Meyer bar coating, and multi-stage reverse coating can be used.

  The thickness of the thermosetting silicone resin layer is preferably 0.03 μm to 0.5 μm, more preferably 0.05 μm to 0.15 μm in terms of the coating thickness after drying. When the coating thickness is 0.03 μm to 0.5 μm, the peeling performance is good, the drying property of the silicone is good, and the silicone migration property is good.

  The release film of the present invention is a release film in which a silicone-glycol copolymer is provided with a thermosetting silicone resin containing 0.4 Wt% to 1.8 Wt% as a release layer.

  As the silicone-glycol copolymer, for example, those obtained by introducing a polyether such as polyethylene oxide or polypropylene oxide into both ends or side chains are preferable. The OH equivalent of the COH group at the polyether end of the silicone-glycol copolymer is preferably 600 to 2000, and more preferably 800 to 1400.

  Specific examples of the silicone-glycol copolymer include product names SH3749 oil and SH3771 oil manufactured by Toray Dow Corning Co., Ltd.

  The silicone-glycol copolymer contained in the thermosetting silicone resin is 0.4 Wt% to 1.8 Wt% of the whole thermosetting silicone resin, preferably 0.4 Wt% to 1.6 Wt%, more Preferably, it is 0.5 Wt% to 1.5 Wt%.

  The surface tension after coating of the silicone-glycol copolymer used in the present invention is preferably 22 to 28 dyne / cm. The silicone-glycol copolymer used in the present invention is preferably a copolymer of hydrophilic glycol and hydrophobic polydimethylsiloxane.

  The release film of the present invention is used to form a ceramic green sheet after coating with ceramic slurry by a doctor blade method and drying. The release film of the present invention has good wettability by providing a silicone-glycol copolymer with a thermosetting silicone resin containing 0.4 Wt% to 1.8 Wt% as a release layer. For example, when used in the production of a ceramic capacitor, it becomes an excellent release film free from sheet pinholes, sheet breakage, and sheet thickness unevenness that occur during green sheet casting. That is, when a coating containing an aqueous solvent such as a ceramic slurry is applied without a sheet pinhole, the silicone-glycol copolymer is a thermosetting silicone resin containing 0.4 Wt% to 1.8 Wt%. By providing as a release layer, wettability is improved and sheet tearing does not occur. In addition, when a coating containing an organic solvent such as a ceramic slurry is applied without a bad skin-like appearance, a silicone-glycol copolymer is thermally cured containing 0.4 Wt% to 1.8 Wt%. Type silicone resin is provided as a release layer.

  The base film of the present invention preferably has a contact angle of 100 ° or more and 110 ° or less with pure water on the surface of the release layer.

  If the contact angle with the pure water on the surface of the release layer is less than 100 °, the peel strength may be too strong, and if it exceeds 110 °, a sheet pinhole may be generated, which is not preferable.

  In the release film of the present invention, the contact angle of toluene on the surface of the release layer is desirably 20 ° or more and 30 ° or less.

  If the contact angle of toluene on the surface of the release layer is less than 20 °, the hydrophobic portion of the low molecular weight silicone may be liberated in the ceramic slurry in the toluene, resulting in a crusty skin-like appearance failure of the ceramic sheet. Because there is, it is not preferable. Further, if the contact angle of toluene on the surface of the release layer is 30 ° or more, wettability is poor and sheet pinholes may occur, which is not preferable.

  In the base film of the present invention, the Ts value of the release layer surface of the release film is preferably 90 or more and 110 or less.

The Ts value is a value obtained by laminating 10 films provided with a release layer and pressing them with a pressure of 300 kg / cm ^2.
Ts value = (Peeling force before pressurization ÷ Peeling force after pressurization) × 100
The value calculated by

  If the Ts value is 90 or less, the difference in peeling force between the surface layer of the product roll and the core becomes large, and a peeling failure occurs at the core, which is not preferable. When the Ts value is 110 or more, the release layer and the resin layer are easily peeled off, which may cause problems such as tunneling.

  As for the base film of this invention, it is desirable for the peeling force of a mold release surface and polyvinyl butyral resin to be 1.0 g / 50mm or more and 3.0g / 50mm or less.

  When the peel force between the release surface and the polyvinyl butyral resin exceeds 3.0 g / 50 mm, the ceramic sheet tears when a thin ceramic sheet of 0.5 μm to 5.0 μm is peeled off Is not preferable. When the peeling force between the release surface and the polyvinyl butyral resin is less than 1.0 g / 50 mm, it may be difficult to produce a thin ceramic sheet of 0.5 μm to 5.0 μm.

  Hereinafter, the present invention will be described in more detail with reference to examples.

  The physical properties in Examples and Comparative Examples were measured as follows.

(1) Peeling force between release surface and polyvinyl butyral resin Sekisui Chemical's polyvinyl butyral (product name: BM-S) was dissolved in toluene: ethanol = 1: 1 solvent to dissolve polyvinyl butyral. Using, it applied so that the application | coating thickness after drying might be set to 5 micrometers on a mold release surface, it was made to dry at 100 degreeC for 2 minute (s) in the hot air oven, and the polyvinyl butyral coating film was created. Thereafter, using a tensile tester, the peel force between the release surface of the release film and the polyvinyl butyral resin layer was measured at a speed of 300 mm / min in the 180 ° direction. The measurement was carried out under conditions of 20 ° C. and 55% Rh. For the peel force between the release surface and the polyvinyl butyral resin, the range from 1.0 g / 50 mm to 3.0 g / 50 mm was marked with ◯, and those outside the range were marked with x.

(2) Contact angle with pure water The contact angle was measured with a contact angle CA-X type manufactured by Kyowa Interface Science Co., Ltd. Pure water was injected into the syringe, 0.3 CC was dropped on the release layer at room temperature, and the contact angle was measured 3 seconds after the dropping. A range from 100 ° to 110 ° was marked with ◯, and a value outside the range was marked with ×.

(3) Contact angle with toluene Except that toluene was used, the contact angle with pure water was measured in the same manner as the method. A range from 20 ° to 30 ° was set as ◯, and a range out of the range was set as ×.

(4) Ts value Ten films provided with a release layer were laminated, and a load of 300 kg / cm ² was applied with a flat press machine and left at room temperature for 24 hours. Thereafter, the film was taken out, and a 31B tape made by Nitto Denko was attached to the release surface with a 5 kg rubber roll. Then, after leaving for 24 hours under the condition of 20 ° C. and 55% Rh, peeling was performed at a rate of 300 mm / min in the 180 ° direction using a tensile tester, and the peeling force was determined. This was taken as the peel force after pressurization. The measurement was carried out under conditions of 20 ° C. and 55% Rh.

  On the other hand, except for laminating 10 films provided with a release layer and not performing a press treatment, 31B tape was bonded in the same manner as above, and thereafter, under the conditions of 20 ° C. and 55% Rh as in the above. After leaving it for 24 hours, it was peeled off at a speed of 300 mm / min in the 180 ° direction using a tensile tester, and the peeling force was determined. This was defined as the peeling force before pressurization. The measurement was performed under the conditions of 20 ° C. and 55% Rh.

Calculate Ts value by the following formula,
Ts value = (Peeling force before pressurization ÷ Peeling force after pressurization) × 100
90 or more and 110 or less were set as ◯, and the case where it was less than 90 and the case where it was larger than 110 were evaluated as x.

(5) Green sheet appearance A ceramic slurry having the following composition was coated on a release film of 200 mm × 250 mm with a wire bar so that the thickness after drying was 5 μm.

<Ceramic slurry composition>
Ceramic powder (barium titanate) 100 parts Polyvinyl butyral resin 5 parts Dioctyl phthalate 1 part Toluene 5 parts Ethanol 5 parts After drying for 1 minute at 120 ° C, green sheet pinholes, crushed skin, repellency are visually confirmed, defects Those having no (pinhole, crushed skin, repellency) are good, and those having a defect (pinhole, crushed skin, repellency) are x.

(6) Comprehensive evaluation Comprehensive evaluation as a release film was performed. The best ◎, good ◯, and poor were marked with ×.

Example 1
1% by weight of silicone-glycol copolymer oil (SH3771 manufactured by Toray Dow Corning Co., Ltd.) is added to 100% of addition reaction type silicone (LTC750A manufactured by Toray Dow Corning) with respect to the solid content, and a platinum catalyst (Toray Dow Corning) is added. A coating solution was prepared by diluting 1% by weight of toluene with SRX212 manufactured by Co., Ltd. to a solid content of 5%.

  The above coating solution is applied to a 38 μm thick polyester film (Lumirror R56 manufactured by Toray Industries, Inc.) using a wire bar so that the coating solution after drying is 0.1 μm, and is dried and cured at 120 ° C. for 30 seconds. Thus, a release film was obtained. Table 1 shows the evaluation results of the obtained release film.

Example 2
To 100% of addition reaction type silicone (LTC750A manufactured by Toray Dow Corning Co., Ltd.), 0.5% by weight of silicone-glycol copolymer oil (SH3771 manufactured by Toray Dow Corning Co., Ltd.) is added to the solid content, and platinum catalyst ( Toray Dow Corning Co., Ltd. product SRX212) 1 weight% was diluted with toluene, and the coating liquid adjusted to 5% of solid content was created.

  The above coating solution is applied to a 38 μm thick polyester film (Lumirror R56 manufactured by Toray Industries, Inc.) using a wire bar so that the coating solution after drying is 0.1 μm, and dried at 120 ° C. for 30 seconds. Cured to obtain a release film. Table 1 shows the evaluation results of the obtained release film.

Example 3
To 100% of addition reaction type silicone (LTC750A manufactured by Toray Dow Corning Co., Ltd.), 1.5% by weight of silicone-glycol copolymer oil (SH3771 manufactured by Toray Dow Corning Co., Ltd.) is added to the solid content, and platinum catalyst ( Toray Dow Corning SRX212) 1% was diluted with toluene to prepare a coating solution adjusted to a solid content of 5%.

  The above coating solution is applied to a 38 μm thick polyester film (Lumirror R56 manufactured by Toray Industries, Inc.) using a wire bar so that the coating solution after drying is 0.1 μm, and is dried and cured at 120 ° C. for 30 seconds. Thus, a release film was obtained. Table 1 shows the evaluation results of the obtained release film.

Example 4
To 100% of addition reaction type silicone (LTC750A manufactured by Toray Dow Corning Co., Ltd.), 0.5% by weight of silicone-glycone-glycol copolymer oil (SH3771 manufactured by Toray Dow Corning) is added to the solid content, and platinum is added. A coating solution was prepared by diluting 1% by weight of a catalyst (SRX212 manufactured by Toray Dow Corning) with toluene to a solid content of 5%.

  Apply the above coating solution to a polyester film (Lumirror R56 manufactured by Toray Industries, Inc.) having a thickness of 920 mm x 15000 m with a thickness of 31 μm, using a gravure coater reverse kiss method and a 150 heliogravure roll. However, it was applied to a thickness of 0.05 μm and dried and cured at an oven length of 30 m, an oven temperature of 150 ° C., and a speed of 60 m / min to obtain a release film. Table 1 shows the evaluation results of the obtained release film.

Comparative Example 1
Addition reaction type silicone (LTC750A manufactured by Toray Dow Corning Co., Ltd.) 100%, platinum catalyst (Toray Dow Corning Co., Ltd. SRX212) 1% by weight was diluted with toluene to prepare a coating solution adjusted to 5% solid content did.

  The above coating solution is applied to a 38 μm thick polyester film (Lumirror R56 manufactured by Toray Industries, Inc.) using a wire bar so that the coating solution after drying is 0.1 μm, and is dried and cured at 120 ° C. for 30 seconds. Thus, a release film was obtained. Table 1 shows the evaluation results of the obtained release film.

Comparative Example 2
Silicone-glycol copolymer oil (SH3771 manufactured by Toray Dow Corning Co., Ltd.) is added in an amount of 0.03% by weight to the solid content, and 1 wt% of platinum catalyst (SRX212 manufactured by Toray Dow Corning Co., Ltd.) is added to a solid content of 5%. An adjusted coating solution was prepared.

  The above coating solution is applied to a 38 μm thick polyester film (Lumirror R56 manufactured by Toray Industries, Inc.) using a wire bar so that the coating solution after drying is 0.1 μm, and is dried and cured at 120 ° C. for 30 seconds. Thus, a release film was obtained. Table 1 shows the evaluation results of the obtained release film.

Comparative Example 3
A platinum catalyst is prepared by adding 2.0% by weight of silicone-glycol copolymer oil (SH3771 manufactured by Toray Dow Corning Co., Ltd.) to 100% of addition reaction type silicone (LTC750A manufactured by Toray Dow Corning Co., Ltd.). (Toray Dow Corning Co., Ltd. SRX212) The coating liquid which adjusted 1 weight% to 5% of solid content was created.

  The above coating solution is applied to a 38 μm thick polyester film (Lumirror R56 manufactured by Toray Industries, Inc.) using a wire bar so that the coating solution after drying is 0.1 μm, and is dried and cured at 120 ° C. for 30 seconds. Thus, a release film was obtained. Table 1 shows the evaluation results of the obtained release film.

Claims (4)

  A release film in which a thermosetting silicone resin containing 0.4 to 1.8 Wt% of a silicone-glycol copolymer is provided as a release layer on at least one surface of a base film. The separation angle according to claim 1, wherein the contact angle with pure water on the surface of the release layer is 100 ° or more and 110 ° or less, and the contact angle with toluene on the surface of the release layer is 20 ° or more and 30 ° or less. Mold film.   The release film of Claim 1 or 2 whose TS value of a release layer surface is 90 or more and 110 or less.   The release film according to any one of claims 1, 2, and 3, wherein a peeling force between the release surface and the polyvinyl butyral resin is 1.0 g / 50 mm or more and 3.0 g / 50 mm or less.