JP2006076051A - Barrier film and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inexpensively provide a barrier film which has a water vapor permeability of 5×10<SP>-3</SP>g/m<SP>2</SP>/day or below and/or an oxygen permeability of 5×10<SP>-3</SP>cc/m<SP>2</SP>/day or below and further, a barrier film required in an EL substrate which has a water vapor permeability of 1×10<SP>-6</SP>g/m<SP>2</SP>/day or below and the oxygen permeability of 1×10<SP>-3</SP>cc/m<SP>2</SP>/day or below. <P>SOLUTION: The barrier film has a structure wherein single barrier layers are formed on both sides of a resin film, each of which comprises a silicon oxide film with a thickness of 5-100 nm and the protective layers, each of which comprises an acrylate or methacrylate film with a thickness of 0.1-3 μm, are provided on both outsides of the barrier layers. The water vapor permeability of the barrier film wherein the barrier layers and the protective layers are formed by a vacuum film forming method is 5×10<SP>-3</SP>g/m<SP>2</SP>/day or below and/or the oxygen permeability thereof is 5×10<SP>-3</SP>cc/m<SP>2</SP>/day or below. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a barrier film having an extremely high barrier property used for an electroluminescence (hereinafter referred to as EL) element substrate and a method for producing the same.

  In recent years, EL displays have been put into practical use as displays that replace LCDs. Since the EL display is self-luminous, it has good visibility and does not require a backlight as used in an LCD. In addition, the response speed is fast and suitable for moving image display. Furthermore, since it has a simple structure compared to LCD and is strong against bending, it is possible to make the device thinner and lighter by changing the EL element substrate from glass to resin, and to take advantage of flexibility. Curved display and flexible display have been proposed. However, the EL element deteriorates in the presence of moisture and oxygen, and forms a dark spot (non-light emitting portion) and grows. Therefore, an extremely high barrier property is required for the resin substrate.

The known literature is described below.
US Pat. No. 6,436,645 (Section 1-3)

Conventionally, when a resin substrate or a resin film is used in an application requiring barrier properties such as an LCD substrate or a food packaging film, the base material is coated with a barrier film such as silicon oxide or aluminum oxide. The barrier property is about 1 to 10 g / m ² / day for general food packaging applications, and only about 0.1 to 0.01 g / m ² / day for LCD applications. By increasing the thickness of the barrier film, it is possible to obtain a film having a higher barrier property. However, if the barrier film is too thick, the stress of the film increases, cracks occur, and the barrier property decreases. Or Thus, there is a limit to the barrier performance obtained by increasing the thickness of the barrier film, a water vapor transmission rate of 1 × 10 ⁻⁶ g / m ² / day or less required for an EL substrate with a single film, and an oxygen transmission rate of 1 × 10 Barrier performance of ⁻³ cc / m ² / day or less has not been achieved at present.

  On the other hand, an organic / inorganic multilayer laminated film in which a plurality of barrier films are laminated via an organic film has been proposed. According to this, if the thickness of the barrier film of one layer is kept in a range where the stress of the film does not become too large, and the barrier film is laminated via the organic film having an excellent stress relaxation function, the film The barrier property can be enhanced without increasing the overall stress (see Patent Document 1).

  However, in order to achieve the extremely high barrier property required for the EL substrate, it is necessary to laminate several layers, and there is a problem that it takes time and cost. For example, when a batch-type film forming apparatus 14 as shown in FIG. 5 produces an organic / inorganic multilayer laminated film on a sheet-like substrate, the substrate is divided into an inorganic film forming chamber 14a and an organic film forming chamber 14b. It is necessary to reciprocate many times, and it takes a very long time to produce one sheet. Further, when a film is formed on a roll-shaped substrate with a winding film forming apparatus 15 in which several inorganic film forming chambers 15a and several organic film forming chambers 15b are provided around a coating drum as shown in FIG. Can produce an organic / inorganic multilayer laminated film in one pass, but requires as many film forming units as the number of layers to be laminated, and the initial size is enormous due to the increase in size of the apparatus. End up.

The present invention has been made to solve the above problems, and has a water vapor transmission rate of 5 × 10 ^−3.
g / m ² / day or less and / or oxygen permeability is 5 × 10 ⁻³ cc / m ² / day or less, and further, water vapor transmission rate required for EL substrate is 1 × 10 ⁻⁶ g / m ² / day or less. A barrier film having an oxygen permeability of 1 × 10 ⁻³ cc / m ² / day or less is provided at a low cost.

The invention according to claim 1 of the present invention is a barrier film in which a barrier layer is formed on both surfaces of a resin film, and the barrier film has a water vapor transmission rate of 5 × 10 ⁻³ g / m ² / day or less and / or Alternatively, the barrier film is characterized by having an oxygen permeability of 5 × 10 ⁻³ cc / m ² / day or less.

The invention according to claim 2 of the present invention is such that at least one of the barrier layers has a water vapor permeability of 1 × 10 ⁻¹ g / m ² / day or less and / or an oxygen permeability of 1 × 10 ^{−. 1} cc / m ² / day or less, preferably, water vapor transmission rate is 2 × 10 ⁻² g / m ² / day or less and / or oxygen transmission rate is 2 × 10 ⁻² cc / m ² / day or less. The barrier film according to claim 1.

  The invention according to claim 3 of the present invention is the barrier film according to claim 1 or 2, wherein the barrier layer is made of nitride, oxide or oxynitride of silicon or aluminum.

  The invention according to claim 4 of the present invention is the barrier film according to any one of claims 1 to 3, wherein the barrier layer is formed by vacuum film formation.

  The invention according to claim 5 of the present invention is the barrier film according to any one of claims 1 to 4, wherein a barrier layer is provided on both sides of the resin film, and a protective layer is further provided on the outer side thereof. .

In the barrier film of the present invention, the barrier layer is formed on both sides of the film. Among the barrier layers, at least one of the barrier layers has a water vapor permeability of 1 × 10 ⁻¹ g / m ² / day or less and / or oxygen. The permeability is 1 × 10 ⁻¹ cc / m ² / day or less, preferably the water vapor permeability is 2 × 10 ⁻² g / m ² / day or less and / or the oxygen permeability is 2 × 10 ⁻² cc / m. ² / day or less, a barrier film having a barrier layer formed on both sides of the present invention has a water vapor transmission rate of 5 × 10 ⁻³ g / m ² / day or less and / or an oxygen transmission rate. Is 5 × 10 ⁻³ cc / m ² / day or less. That is, the barrier film of the present invention is a single film and achieves barrier performance required for an EL substrate.

The invention according to claim 6 of the present invention is any one of claims 1 to 5, wherein a barrier layer is formed on both sides of a transparent resin film having a thickness of 50 to 200 μm, and a protective layer is formed on the outer side thereof. The method for producing a barrier film according to the item includes at least the following steps.
(A) The barrier layer is formed by vacuum film formation, and a barrier layer made of a silicon oxide film is formed to a thickness of 5 nm to 100 nm.
(B) A step in which the protective layer is formed by vacuum film formation, and a protective layer made of an acrylate or methacrylate film is formed to a thickness of 0.1 to 3 μm.

ADVANTAGE OF THE INVENTION According to this invention, the barrier film of the element substrate for EL with sufficient interception of water and oxygen can be provided. That is, by forming a single barrier layer on both sides of the film without increasing the thickness of the barrier layer, the water vapor transmission rate required for an EL substrate is 1 × 10 ⁻⁶ g / m ² / day or less, and the oxygen transmission rate is 1 The barrier performance of × 10 ⁻³ cc / m ² / day or less can be cleared.

  ADVANTAGE OF THE INVENTION According to this invention, the barrier film for board | substrates for EL with sufficient interception of water and oxygen can be provided. Moreover, according to the method for producing a barrier film in which a single-layer barrier layer is formed on both sides of the film of the present invention, the production process is simplified as compared with a multilayer film of organic / inorganic layers on one side of the film. Thus, the barrier film can be manufactured at a low cost.

  Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the barrier film 1 according to the present invention has a basic structure including a configuration in which a barrier layer 3 is provided on both surfaces of a resin film 2. That is, the barrier film 1 is an invention having a basic structure of / barrier layer 3 / resin film 2 / barrier layer 3 /.

  Although it does not specifically limit as the resin film 2 used for this invention, For example, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyethylene naphthalate film, a polycarbonate film, a polyether sulfone film, a polysulfone film, a polyarylate film, a cyclic polyolefin film etc. Can be mentioned. Of these, polycarbonate and polyethersulfone having excellent transparency and heat resistance are preferably used. Various known additives and stabilizers such as an antistatic agent, an ultraviolet ray preventing agent, a plasticizer, and a lubricant may be used on the surface of these substrates. In order to improve the adhesion with the barrier layer, corona treatment, low-temperature plasma treatment, or ion bombardment treatment may be performed as pretreatment.

  The thickness of the resin film 2 is arbitrary, but is preferably as thin as possible from the viewpoint of thinning and lightening the element. However, in consideration of handling properties in the subsequent process, practically, about 50 μm to 200 μm is preferable.

The barrier layer 3 of the present invention has a water vapor transmission rate of 1 × 10 ⁻¹ g / m ² / day or less and / or an oxygen transmission rate of 1 × 10 ⁻¹ cc / m ² / day or less, preferably a water vapor transmission rate. Is a deposited film of a nitride or oxide or oxynitride of silicon or aluminum having an oxygen permeability of 2 × 10 ⁻² g / m ² / day or less and / or an oxygen permeability of 2 × 10 ⁻² cc / m ² / day or less is there. However, the barrier layer of the present invention is not limited to the above-described deposited film, and any material that satisfies the above barrier properties can be used. Moreover, it is preferable that the thickness of a barrier layer is 5-100 nm, More preferably, it is 10-50 nm. If the thickness is less than 5 nm, the barrier property is insufficient, and if it exceeds 100 nm, the stress of the film increases and cracks tend to occur.

In the barrier film having the layer structure of the present invention as a basic structure, the barrier property of the film is remarkably improved by providing the barrier layer on both surfaces of the resin film by vacuum film formation. It is known that the transmittance Pt of the laminate is theoretically 1 / Pt = 1 / P1 + 1 / P2 + 1 / P3 + ... + 1 / Pn where the transmittance of each layer is P1, P2, P3. . Therefore, the water vapor transmission rate when two barrier layers are laminated is improved to about half of the water vapor transmission rate of a single layer. For example, the water vapor transmission rate of a single layer is 2 × 10 ⁻² g / m. ^{In the case of} a barrier layer of ² / day, the water vapor transmission rate of the laminated barrier layer is about 1 × 10 ⁻² g / m ² / day. On the other hand, as in the present invention, the water vapor permeability of a barrier film in which barrier layers are provided on both surfaces of a resin film by vacuum film formation is 5 × 10 ⁻³ g / m ² / day or less. At present, a method for accurately evaluating a barrier film of 5 × 10 ⁻³ g / m ² / day or less has not been completed. However, when this barrier film is evaluated by the recently studied calcium method, The transmittance is 1 × 10 ⁻⁶ g / m ² / day, which is much better than the result of laminating two layers on one side. The theoretical clarification of why such a special effect is achieved by providing the barrier layer on both sides of the resin film by vacuum film formation is not sufficient, but the barrier film of the present invention has a repeated experiment. As a result, there is an effect of repeated reproduction.

  There are various vacuum film forming methods, and examples thereof include a vacuum deposition method, an ion plating method, a sputtering method, and a plasma CVD method. In the present invention, a sputtering method and a plasma CVD method are mainly used. Further, it is desirable to use a winding type vacuum film forming apparatus that can perform continuous film formation by winding utilizing the characteristics of the resin film.

  Furthermore, in this invention, as shown in FIG. 2, the barrier film 1 concerning this invention consists of the structure which provided the barrier layer 3 on both surfaces of the resin film 2, and provided the protective layer 4 on the outer side of this barrier layer. Is the basic structure. That is, the barrier film 1 is an invention having a basic structure of / protective layer 4 / barrier layer 3 / resin film 2 / barrier layer 3 / protective layer 4 /.

  As shown in FIG. 2, a protective layer 4 may be provided outside the barrier layer 3. As long as the protective layer 4 does not interfere with the transparency of the barrier film, the material and the film forming method thereof are not particularly limited. However, when film formation is performed by winding, after the barrier film is formed, the barrier film deteriorates due to contact with the roller while the film formation surface is running or contact with the back surface of the film after winding. Therefore, in order to prevent this, it is desirable to form a protective layer in-line using a technique such as organic vapor deposition after the formation of the barrier layer and before the film formation surface comes into contact with the roller.

  Next, an example of a winding type vacuum film forming apparatus for forming a barrier layer in the present invention will be shown. FIG. 3 is a schematic view thereof, in which a plasma CVD method is applied as a barrier layer forming method and an organic vapor deposition method is applied as a protective film forming method. The vacuum film forming apparatus 5 includes a winding layer 5a, a barrier layer forming chamber 5b disposed around the coating drum 7, and a protective layer forming chamber 5c. Each chamber is isolated by a shielding plate (6a to 6c). Yes. The winding system is formed by unwinding and winding rollers (8a, 8b), a coating drum and guide rollers (9a-9d).

  Hereinafter, a method for producing the barrier film will be described.

  The roll-shaped resin film 10 is mounted on the unwinding roller 8a, and a film transport path reaching the winding roll 8b through the plurality of guide rollers (9a to 9d) and the coating drum 7 is formed. After the vacuum device 5 is evacuated, a barrier layer and a protective layer are formed in this order on the inner surface of the resin film. Thereafter, the inside of the vacuum device 5 is opened to the atmosphere, and the inner surface is formed into a film, and the roll-shaped resin film 10 is removed from the winding roll 8b. It is mounted again on the unwinding roller 8a. However, this time, the transport path is changed as shown in FIG. 4 so that the outer surface of the film becomes the film formation surface. Then, similarly to the case where each layer is formed on the inner surface of the film, the inside of the vacuum device 5 is evacuated, and then the barrier layer and the protective layer are formed in this order on the outer surface of the resin film. As described above, the barrier layer and the protective layer were formed on both surfaces of the resin film 10.

  As a method for forming a barrier film by a plasma CVD method, for example, a silicon oxide film is formed using, as a raw material, an organic silicon compound and oxygen gas added, and optionally an inert gas added thereto. Can do. Examples of organosilicon compounds include relatively low molecular weights such as tetraethoxysilane (TEOS), tetramethoxysilane (TMOS), tetramethylsilane (TMS), hexamethyldisilane, hexamethyldisiloxane (HMDSO), and hexamethyldisilazane. Select one or more materials to use. These organosilicon compounds are mixed with oxygen gas, introduced into an electrode 11 having a shower head of a vacuum film forming apparatus, plasma is generated between the coating drum 7 and the electrode 11, and a silicon oxide film is formed by plasma CVD. Is deposited on a film.

As a method of forming the protective layer by the organic vapor deposition method, for example, acrylate or methacrylate or a mixed resin solution thereof is evaporated by the organic vapor deposition device 12 and condensed on the film on the coating drum 7. Then, a protective layer can be formed by performing a curing process with the electron beam irradiation device 13. Further, ultraviolet curing may be used instead of electron beam curing.
EXAMPLES Next, an Example is given and this invention is demonstrated further.

  A barrier layer made of a 20 nm silicon oxide film was formed on both sides of a 200 μm thick polyethersulfone film (hereinafter referred to as PES film) by a plasma CVD method using a batch type vacuum film forming apparatus. The layer structure of the barrier film of Example 1 is barrier layer / PES film / barrier layer.

  A 20 nm silicon oxide film was formed on both sides of a PES film having a thickness of 200 μm by a plasma CVD method using a take-up vacuum film forming apparatus, and a 1 μm protective film was further formed on the outer side by an organic vapor deposition method. The layer structure of the barrier film of Example 2 is protective film / barrier layer / PES film / barrier layer / protective film.

  A silicon oxide film having a thickness of 20 nm was formed on both surfaces of a PES film having a thickness of 200 μm by a plasma CVD method using a take-up vacuum film forming apparatus. The layer structure of the barrier film of Example 3 is barrier layer / PES film / barrier layer.

  Examples 4 to 5 will be described below as comparative examples of the present invention.

  A 20 nm silicon oxide film is formed on one side of a 200 μm thick PES film by a plasma CVD method using a batch-type vacuum film forming apparatus, a 1 μm protective film is formed on the outside by an organic vapor deposition method, and a plasma is formed on the outside. A 20 nm silicon oxide film was formed by CVD. The layer structure of the barrier film of Example 4 is PES film / barrier layer / protective film / barrier layer.

  A silicon oxide film having a thickness of 10 nm was formed on both sides of a PES film having a thickness of 200 μm by a plasma CVD method using a batch type vacuum film forming apparatus. The layer structure of the barrier film of Example 5 is barrier layer / PES film / barrier layer.

  Next, the barrier films of the samples of Examples 1 to 5 and Examples 4 to 5 as comparative examples were measured. The water vapor permeability and oxygen permeability of the barrier films of Examples 1 to 5 were measured and evaluated by the following methods. The water vapor transmission rate was measured using a water vapor transmission measurement device (manufactured by Modern Control, PERMATRAN W3 / 33) in an atmosphere of a temperature of 40 ° C. and a humidity of 90% RH. The water vapor transmission rate below the detection limit of the apparatus was measured by the calcium method. Specifically, a calcium layer is formed on a glass substrate, which is sealed with a sealant and a barrier film, and stored in an atmosphere of a temperature of 40 ° C. and a humidity of 90% RH. Since the calcium layer is converted from a metallic color to transparent calcium hydroxide by the permeation of moisture, the film thickness of the calcium layer is calculated by measuring the light transmittance, the amount of calcium reacted with the moisture is obtained, and the water vapor transmission The rate was calculated. The oxygen permeability measuring method was measured using an oxygen permeability measuring device (manufactured by Modern Control, MOCON OXTRAN 10 / 50A) in an atmosphere of a temperature of 30 ° C. and a humidity of 70% RH. The measurement results are shown in Table 1.

なお、水蒸気透過率の単位はｇ／ｍ²／ｄａｙ、酸素透過率の単位は、ｃｃ／ｍ²／ｄａ
ｙ・ａｔｍである。

The unit of water vapor transmission rate is g / m ² / day, and the unit of oxygen transmission rate is cc / m ² / day.
y · atm.

From the results of Table 1, the barrier film in which the barrier film is laminated on one side, for example, the barrier film of the present invention in which the barrier layer is provided on both sides of the barrier film rather than the barrier film of Example 4, for example, Examples 1-3 It can be seen that the barrier film has much better barrier properties. However, even when the barrier property of a single layer exceeds 1 × 10 ⁻¹ g / m ² / day as in the barrier film of Example 5 as a comparative example, even when a barrier layer is provided on both sides. Barrier properties sufficient for use in EL substrates and the like are not exhibited. Moreover, when producing this barrier film by winding up, in Example 2 and Example 3, for example, the barrier film of Example 2 which provided the protective layer shows the superior barrier property.

It is explanatory drawing which represented the embodiment of the barrier film of this invention with the side cross section. It is explanatory drawing which represented the other embodiment which provided the protective layer in the both outer sides of the barrier layer of the barrier film of this invention with the side cross section. It is a schematic explanatory drawing which shows the whole figure of the winding type vacuum film-forming apparatus in connection with this invention, and has shown the conveyance path | pass in the case of film-forming the inner surface of a film. It is a schematic explanatory drawing which shows the whole view of the winding type vacuum film-forming apparatus in connection with this invention, and has shown the conveyance path | pass in the case of forming the outer surface of a film. It is a schematic explanatory drawing which shows the whole batch type vacuum film-forming apparatus for producing the conventional organic / inorganic multilayer laminated film. It is a schematic explanatory drawing which shows the whole figure of the winding-type vacuum film-forming apparatus for producing the conventional organic / inorganic multilayer laminated film.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Barrier film 2 ... Resin film 3 ... Barrier layer 4 ... Protective layer 5 ... Winding type vacuum film-forming apparatus 5a for producing the barrier film of this invention ... Barrier layer film-forming chamber 5b ... Protective layer film-forming chamber 6a 6b, 6c ... partition wall 7 ... coating drum 8a ... unwinding roller,
8b: Winding rollers 9a, 9b, 9c, 9d ... Guide roller 10 ... Resin film roll 11 ... CVD electrode 12 ... Organic matter vapor deposition device 13 ... Electron beam irradiation device 14 ... Batch type for producing organic / inorganic multilayer laminated film Vacuum film forming apparatuses 14a, 14c ... Inorganic film forming chambers 14b, 14d ... Organic film forming chambers 15 ... Winding type vacuum film forming apparatus 15a for producing organic / inorganic multilayer laminated films ... Inorganic film forming chambers 15b ... Organic film deposition chamber

Claims (6)

A barrier film having a barrier layer formed on both sides of a resin film, wherein the barrier film has a water vapor transmission rate of 5 × 10 ⁻³ g / m ² / day or less and / or an oxygen transmission rate of 5 × 10 ⁻³ cc A barrier film characterized by being / m ² / day or less. Among the barrier layers, at least one of the barrier layers has a water vapor transmission rate of 1 × 10 ⁻¹ g / m ² / day or less and / or an oxygen transmission rate of 1 × 10 ⁻¹ cc / m ² / day or less, preferably 2. The barrier film according to claim 1, wherein the water vapor transmission rate is 2 × 10 ⁻² g / m ² / day or less and / or the oxygen transmission rate is 2 × 10 ⁻² cc / m ² / day or less. .   The barrier film according to claim 1, wherein the barrier layer is made of a nitride or oxide or oxynitride of silicon or aluminum.   The barrier film according to any one of claims 1 to 3, wherein the barrier layer is formed by vacuum film formation.   The barrier film according to any one of claims 1 to 4, wherein a barrier layer is provided on both surfaces of the resin film, and a protective layer is further provided on the outer side thereof. The method for producing a barrier film according to any one of claims 1 to 5, wherein a barrier layer is formed on both sides of a transparent resin film having a thickness of 50 to 200 µm, and a protective layer is formed on the outside thereof. The manufacturing method of the barrier film characterized by including the following processes.
(A) The barrier layer is formed by vacuum film formation, and a barrier layer made of a silicon oxide film is formed to a thickness of 5 nm to 100 nm.
(B) A step in which the protective layer is formed by vacuum film formation, and a protective layer made of an acrylate or methacrylate film is formed to a thickness of 0.1 to 3 μm.

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