JP2019181815A - Laminate film and flexible organic el device using the same - Google Patents

Abstract

To provide a laminate film capable of suppressing moisture permeation through an end face, and a flexible organic EL device suppressing moisture permeation through an end face of a laminate film and having long-term sealing reliability.SOLUTION: A laminate film 20 comprises at least two gas barrier films 10(A) each having a substrate film 1 and a gas barrier layer 2 formed on one surface of the substrate film, bonded to each other with an adhesive layer 3. In the laminate film 20, the at least two gas barrier films comprise the gas barrier film 10(A) and a gas barrier film 10(B) having an outer dimension smaller than that of the gas barrier film 10(A), and the gas barrier film 10(B) is laminated on the gas barrier film 10(A) in such a manner that the outer circumference of the gas barrier film 10(B) is located inside the outer circumference of the gas barrier film 10(A).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a laminated film and a flexible organic EL device using the laminated film.

  In recent years, a device using a film as a substrate is advantageous in that it is lighter and more flexible than a device using a glass substrate, and the substrate is less likely to be damaged. Is expected.

  The organic EL can be structurally made extremely thin. Therefore, in order to make use of this feature, a flexible organic EL device using a plastic film as a substrate has attracted attention. Organic EL is very weak to moisture and oxygen, and the light emitting material is altered by the moisture and oxygen, and the electrodes are oxidized, resulting in light emission defects called dark spots (hereinafter abbreviated as DS) and light emitting shrink. There is a problem. Therefore, when using a plastic film for the substrate, a transparent plastic film having gas barrier properties is used. The most common gas barrier film is a highly transparent gas barrier film in which an inorganic vapor deposition film made of silicon oxide, aluminum oxide, magnesium oxide or the like is formed on the surface of a substrate made of a plastic film. Many such highly transparent gas barrier films have been proposed and put into practical use, but many of them are insufficient as barrier levels required as protective materials for organic EL elements.

For the purpose of improving the gas barrier property of a gas barrier film, for example, Patent Document 1 discloses a gas barrier laminate film in which a plurality of gas barrier laminates having at least two inorganic thin film layers are laminated on the surface of a base film. Has been. In the gas barrier laminate film described in Patent Document 1, the base film side and the surface of the inorganic thin film layer are bonded to each other through an adhesive layer. Patent Document 2 discloses a laminated film having a laminated body in which at least two gas barrier films are bonded together via an adhesive layer, and a seal layer formed on one surface of the laminated body. Has been. The laminated film described in Patent Document 2 has a water vapor permeability of 40 ° C. and 90% R.D. H. And 0.03 g / m ² · day · atm or less.

International Publication No. 2009/139391 JP 2013-54985 A

  Since the configurations of Patent Documents 1 and 2 have a structure in which a plurality of gas barrier films are bonded together, the moisture resistance against moisture permeation from the surface direction of the gas barrier film is high. However, even when a plurality of gas barrier films are bonded together, it cannot be said that the moisture barrier property is sufficient with respect to moisture permeation from the end face direction of the gas barrier film. Therefore, there is a possibility that moisture permeates from the end face of the base material of the gas barrier film or the end face of the adhesive layer and moisture reaches the organic EL layer, so that the electrode is oxidized and no light is emitted.

  The present invention has been made to solve the above-described problems, and a laminated film capable of suppressing moisture permeation from an end surface, and a flexible film that suppresses moisture permeation from the end surface of the laminated film and has long-term sealing reliability. An object is to provide an organic EL device.

  The present invention relates to a laminated film in which two or more gas barrier films having a base film and a gas barrier layer formed on one surface of the base film are bonded together with an adhesive, and two or more gas barriers are provided. The gas-resistant film is composed of a gas-barrier film (A) and a gas-barrier film (B) having an outer dimension smaller than that of the gas-barrier film (A). It is a laminated film characterized by being laminated on the gas barrier film (A) so as to be located inside the outer periphery.

  Moreover, this invention is the sealing film formed on the said laminated | multilayer film, the organic EL element formed on the gas barrier film (B) of a laminated film, the sealing agent which seals an organic EL element, and a sealing agent The flexible organic EL device is characterized in that the end face of the gas barrier film (B) is covered with a sealing agent.

  Moreover, it is preferable that a sealing agent contains a hygroscopic agent.

  ADVANTAGE OF THE INVENTION According to this invention, the moisture permeability from the end surface of a laminated film which can suppress moisture transmission from an end surface, and a laminated film are suppressed, and the flexible organic EL device with long-term sealing reliability is realizable.

It is sectional drawing which shows the 1st structural example of the laminated film which concerns on embodiment of this invention. It is sectional drawing which shows the 2nd structural example of the laminated film which concerns on embodiment of this invention. It is a cross-sectional schematic diagram which shows the flexible organic EL device which concerns on embodiment of this invention. It is sectional drawing which shows the structural example of the conventional laminated | multilayer film.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings. Note that the drawings referred to in the following description of the embodiments are for explaining the configuration of the present invention, and the size, thickness, dimensions, and the like of each part shown in the drawings are different from the actual ones. The present invention is not limited to these.

  An example of an embodiment of the laminated film of the present invention will be described with reference to FIG.

  The embodiment of the present invention exemplifies a configuration for embodying the technical idea of the present invention, and specifies the material, shape, structure, arrangement, dimensions, etc. of each part as follows. is not. The technical idea of the present invention can be variously modified within the technical scope defined by the claims described in the claims.

<Laminated film>
FIG. 1 is a cross-sectional view showing a first configuration example of a laminated film according to an embodiment of the present invention. A laminated film 20 shown in FIG. 1 includes a gas barrier film 10 (A) in which a gas barrier layer 2 is formed on one surface of a base film 1, and one of the base films 1 on the gas barrier film 10 (A). A gas barrier film 10 (B) in which the gas barrier layer 2 is formed on the surface is bonded through the adhesive layer 3. The gas barrier film 10 (B) is smaller in size (outer dimensions) than the gas barrier film 10 (A). The gas barrier film 10 (B) is bonded so that the outer periphery is located inside the outer periphery of the gas barrier film 10 (A).

  In FIG. 1, one gas barrier film 10 (B) is bonded to the gas barrier film 10 (A). However, as shown in FIG. 2, an adhesive is applied to the gas barrier film 10 (A). Two or more gas barrier films 10 (B) can be bonded together through the layer 3. FIG. 2 shows a second configuration example of the laminated film according to the embodiment of the present invention, in which two gas barrier films 10 (B) are bonded to the gas barrier film 10 (A). Further, one gas barrier film 10 (B) may be bonded to two or more gas barrier films 10 (A) via the adhesive layer 3. In the laminated film 20, the gas barrier film (B) is not laminated on the lower surface side of the gas barrier film (A), and the gas barrier film (A) is laminated on the upper surface side of the gas barrier film (B). It has no configuration.

(1) Base film 1
As the base film 1, a plastic film having a high transmittance to visible light is used. For example, a polyester film such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), a polyolefin film such as polyethylene or polypropylene, a polystyrene film, Polyamide films such as 6-nylon, polycarbonate films, polyimide films, polyvinyl chloride, and the like can be used. These plastic films may be uniaxially stretched, biaxially stretched, or unstretched films, and those having mechanical strength and dimensional stability are preferred. As for the thickness of the base film 1, 6 micrometers or more and 300 micrometers or less are desirable.

  The base film 1 is a known additive such as an antistatic agent, a light blocking agent, an ultraviolet absorber, a plasticizer, a lubricant, a filler, a colorant, a stabilizer, a lubricant, a crosslinking agent, an antiblocking agent, An antioxidant etc. can be contained.

  On the base film 1, an anchor coat agent (not shown) may be appropriately formed by applying an anchor coating agent in order to improve the adhesion with the gas barrier layer 2 and to flatten the surface layer of the base film 1. I can do it. As anchor coating agents, solvent-based or water-soluble polyester resins, isocyanate resins, urethane resins, acrylic resins, vinyl-modified resins, vinyl alcohol resins, vinyl butyral resins, ethylene vinyl alcohol resins, nitrocellulose resins, oxazoline group-containing resins, carbodiimides A group-containing resin, a methylene group-containing resin, an epoxy group-containing resin, a modified styrene resin, a modified silicone resin, and an alkyl titanate can be used alone or in combination of two or more.

  The anchor coat layer may contain a silane coupling agent, a titanium coupling agent, a light blocking agent, an ultraviolet absorber, a stabilizer, a lubricant, an antiblocking agent, an antioxidant, and the like. Moreover, what copolymerized them with the said resin can be used as a material of an anchor coat layer.

  As a method for forming the anchor coat layer, a known coating method is appropriately adopted. For example, a roll coating method, a gravure coating method, a spray coating method, an air knife coating method and the like can be used. The thickness of the anchor coat layer is preferably 0.005 to 5 μm. If the anchor coat layer has a thickness of 5 μm or less, the slipperiness is good, there is almost no peeling from the base film 1 due to the internal stress of the anchor coat layer itself, and the thickness is 0.005 μm or more. If so, a uniform thickness can be maintained.

(2) Gas barrier layer 2
The gas barrier layer 2 is a layer that prevents permeation of gases such as water vapor and oxygen, and is formed on at least one surface of the base film 1. The gas barrier layer 2 is not particularly limited as long as it has a gas barrier property.

As the gas barrier property, the water vapor permeability is preferably 0.01 g / m ² · day · atm or less. Usually, the gas barrier layer is an inorganic layer (sometimes referred to as an inorganic layer). Typical examples of the inorganic substance contained in the inorganic layer include boron, magnesium, aluminum, silicon, titanium, zinc, and tin oxides, nitrides, oxynitrides, carbides, hydrides, and the like. These may be pure substances or a mixture comprising a plurality of compositions. Of these, aluminum oxide, nitride or oxynitride, or silicon oxide, nitride or oxynitride, or a mixture thereof is preferable.

  The inorganic layer as the gas barrier layer 2 may be a single layer or a laminate of a plurality of layers. When the gas barrier layer 2 has a laminated structure, it may be a laminate of an inorganic layer and an organic layer, or may be an alternating laminate of a plurality of inorganic layers and a plurality of organic layers. Further, the gas barrier layer 2 may include a gradient material layer. The optimum thickness of the gas barrier layer 2 varies depending on the type, configuration, and formation method of the gas barrier material used, but is preferably in the range of 3 nm to 10 μm. If the film thickness is less than 3 nm, the function as a gas barrier cannot be sufficiently achieved. If the film thickness exceeds 10 μm, the transparency and flexibility of the film are lowered, and external force such as bending and pulling after film formation is reduced. There is a risk that the thin film will crack.

  A method for forming the gas barrier layer 2 is not particularly limited. For example, a vacuum deposition method, a sputtering method, a reactive sputtering method, an atomic deposition method, a molecular beam epitaxy method, a cluster ion beam method, an ion plating method, a plasma polymerization method, An atmospheric pressure plasma polymerization method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used. Further, the transmittance of the gas barrier layer 2 is desirably 80% or more in the visible light region when light is extracted from the support substrate side in the organic EL device using the laminated film 20 as the support substrate.

(3) Adhesive layer 3
The adhesive layer 3 is a layer for stacking and bonding two or more gas barrier films 10 together.

For the adhesive layer 3, it is preferable to use an adhesive with few foreign matters and bubbles in the adhesive. For example, an epoxy-curing adhesive or a main agent having a hydroxyl group such as rubber, silicone, acrylic or urethane. An adhesive that is cured with an isocyanate curing agent can be used. The forming method is preferably a dry laminating method, and a gravure coater, a dip coater, a wire bar coater, a die coater or the like can be used as a coating method. The coating amount of the adhesive is preferably 0.1 to 10 g / m ² (dry state).

(4) Laminated film 20
The laminated film 20 is a laminate of gas barrier films 10 having different sizes. The gas barrier film 10 (B) having a smaller size than the gas barrier film 10 (A) is formed on the gas barrier film 10 (A), and the outer periphery of the gas barrier film 10 (B) is the outer periphery of the gas barrier film 10 (A). It is pasted so that it may be located inside. After a plurality of gas barrier films 10 (A) are bonded together, a plurality of gas barrier films 10 (A) and gas barrier films 10 (B) may be bonded together, or the gas barrier films 10 (A) ) A plurality of gas barrier films 10 (B) bonded together may be bonded together. When the gas barrier film 10 (A) and the gas barrier film 10 (B) are rectangular in plan view, the gas barrier film 10 (A) may be 1 to 20 mm larger per side than the gas barrier film 10 (B). desirable.

<Organic EL device>
An example of the flexible organic EL device according to the embodiment of the present invention will be described with reference to FIG. FIG. 3 is a schematic cross-sectional view showing a flexible organic EL device according to an embodiment of the present invention. As shown in FIG. 3, the flexible organic EL device 40 includes a laminated film 20, an organic EL element 50 formed on the gas barrier film 10 (B) of the laminated film 20, and a seal that seals the organic EL element 50. Agent 5 and sealing film 30 formed on sealant 5 are provided. The laminated film 20 is the same as the laminated film 20 shown in FIG. Hereinafter, the configuration of the laminated film 20 and the organic EL element 50 is referred to as an organic EL element substrate 21. The sealing agent 5 includes the hygroscopic agent 4 and is formed so as to cover the entire end face of the gas barrier film 10 (B). The organic EL element 50 may be a known organic EL element including an organic EL layer formed between a pair of electrode layers, and the configuration and material are not particularly limited.

(5) Sealing film 30
As the sealing film 30, the previously described gas barrier film 10, metal foil, or the like is preferably used. As the gas barrier property, the water vapor permeability is preferably 0.01 g / m ² · day · atm or less. More preferably, it is 0.005 g / m ² · day · atm or less. When taking out organic EL light emission from the sealing film 30 side, the visible light transmittance of the sealing film is desirably 80% or more. On the other hand, when taking out organic EL light emission from the laminated film 20 side, the visible light transmittance of the sealing film 30 is not particularly limited. Although the thickness of the film 30 for sealing is not specifically limited, 10 micrometers-300 micrometers are preferable.

(6) Sealant 5
The sealing agent 5 is formed between the gas barrier film 10 (A) and the sealing film 30, seals the organic EL element 50, and forms an end surface of the gas barrier film 10 (B) of the organic EL element substrate 21. It is formed so as to cover the entire surface.

  The sealing agent 5 is preferably a sealing agent with few foreign matters and bubbles in the sealing agent. For example, an epoxy-curing adhesive or a main agent having a hydroxyl group such as rubber, silicone, acrylic or urethane is used. An adhesive that is cured with an isocyanate curing agent can be used. The sealing agent 5 is formed in an inert gas atmosphere. For example, screen printing, dispensing, or a transfer method in which the sealant 5 is previously formed on another substrate and transferred can be appropriately used. The thickness of the sealing agent 5 that covers the gas barrier film 10 and the organic EL element 50 is preferably 3 μm or more and 200 μm or less, and more preferably 10 μm or more and 100 μm or less.

(7) Hygroscopic agent 4
The moisture absorbent 4 can remove moisture and the like, for example, an inorganic compound such as alkali metal oxide, alkaline earth metal oxide, sulfate, metal halide, perchlorate, acrylic or methacrylic Organic materials such as water-absorbing polymers, metals selected from alkali metals and alkaline earth metals or alloys thereof, general hygroscopic agents such as activated alumina, silica gel, zeolite, etc. can be used. Species or two or more can be used. For the removal of moisture, it is preferable to use an alkali metal oxide and / or alkaline earth metal oxide that chemically adsorbs moisture as a hygroscopic agent, rather than a general hygroscopic agent that physically adsorbs moisture. The moisture absorbent is preferably in the range of 1 to 70% by volume, more preferably 5 to 50% by volume with respect to the sealant 5. Further, the hygroscopic agent may be solid or liquid.

The organic EL element substrate 21 on which the sealing agent 5 is formed and the sealing film 30 are bonded together under an inert gas atmosphere, and are bonded while being bent so that bubbles do not enter the sealing agent 5. In consideration of the bonding stability, prevention of bubbles from being mixed into the bonding portion, etc., it is more preferable to carry out under a reduced pressure of 10 to 1 × 10 ⁻⁵ Pa and a pressure of 0.01 to 0.5 MPa.

  According to the laminated film of the present invention, the end face of the gas barrier film 10 (B) or the end face of the adhesive layer 3 formed between the gas barrier film 10 (A) and the gas barrier film 10 (B) is provided. It can be covered with a sealing agent, and as a result, moisture permeation from the end face of the gas barrier film 10 (B) and the end face of the adhesive layer 3 can be suppressed. Moreover, according to the flexible organic EL device using the laminated film according to the present invention, it is formed between the end face of the gas barrier film 10 (B) or between the gas barrier film 10 (A) and the gas barrier film 10 (B). It becomes possible to suppress moisture permeation from the end face of the adhesive layer 3 made. Moreover, according to the flexible organic EL device which concerns on this invention, the sealing agent 5 contains the hygroscopic agent 4, can delay the moisture permeation from the end surface direction of the sealing agent 5, As a result, long-term sealing It can have reliability.

  The laminated film according to the present invention can be applied to various devices such as electronic paper and liquid crystal display in addition to the flexible organic EL device.

  Specific examples of the present invention will be described below.

<Example 1>
PEN having a film thickness of 25 μm was used as the base film 1, and a silicon nitride film (gas barrier layer 2) having a thickness of 0.5 μm was formed on the base film 1 by plasma chemical vapor deposition to obtain a gas barrier film 10. . This gas barrier film has a water vapor permeability of 40 ° C. and 90% R.D. H. And 5 mg / m ² · day · atm.

  Next, the produced gas barrier film 10 was cut to obtain 100 mm square gas barrier films 10 (A) and 80 mm square gas barrier films 10 (B) having different sizes. Next, the silicon nitride film surface of the gas barrier film 10 (A) and the PEN surface of the gas barrier film 10 (B) are bonded together by a laminate method through an epoxy curable adhesive (film thickness: 5 μm), A laminated film 20 was obtained. At this time, it bonded so that the outer periphery of the gas barrier film (B) 10 might be located inside the outer periphery of the gas barrier film 10 (A).

  Next, the organic EL element 50 was formed on the silicon nitride film surface of the gas barrier film 10 (B) of the laminated film 20 to obtain an organic EL element substrate 21. The organic EL element 50 is formed by forming an anode (ITO) by a vacuum film formation method, and forming a hole transport layer, an organic EL layer as a light emitting layer, a cathode (Ba / Al), and a passivation film on the anode (ITO). Obtained. The light emitting area was 60 mm square.

As the sealing film 30, an aluminum foil / PET composite film was used. The sealing film 30 and the organic EL element substrate 21 on which the sealing agent 5 to which 10% by volume of zeolite having a particle size of 0.6 μm was added were bonded. The sealant 5 was formed in an area of 90 mm square using an epoxy curable adhesive (film thickness: 25 μm) so as to cover the entire end face of the gas barrier film 10 (B). Bonding was performed at a vacuum of 1 × 10 ⁻¹ Pa and a pressure of 0.3 MPa. Thus, the flexible organic EL device 40 was obtained.

<Example 2>
As shown in FIG. 2, a laminated film 20 having a layer configuration of gas barrier film 10 (B) / adhesive layer / gas barrier film 10 (B) / adhesive layer / gas barrier film 10 (A) was used. A flexible organic EL device 40 was obtained in the same procedure as in Example 1 except that.

<Comparative Example 1>
As shown in FIG. 4, it was carried out except that a laminated 20 film having a gas barrier film 10 / adhesive layer / gas barrier film 10 layer structure using two gas barrier films having the same size was used. The flexible organic EL device 40 was obtained by the same procedure as in Example 1.

(Evaluation)
The flexible organic EL device 40 produced in Examples 1 and 2 and Comparative Example 1 was subjected to 60 ° C. and 90% R.D. H. The DS (dark spot) size and the presence or absence of light emitting shrinkage were confirmed. When the average diameter size was less than 100 μm, the DS size was determined to be ◯ (= non-defective product), and when the average diameter size was 100 μm or more, it was determined to be x (= defective). If there was no light emission shrinkage, it was determined as ◯ (= non-defective product), and a case where light emission shrinkage occurred was determined as x (= defective).

  The planar shape of the DS is almost a perfect circle or almost a perfect circle, but may be an ellipse or a polygon. Therefore, in this evaluation, when the planar shape of the DS is an ellipse, the length in the longitudinal direction of the ellipse is defined as the “diameter”. When the DS planar shape is a polygon, the length of the longest straight line passing through the center of gravity of the polygon and connecting any two points on the side is defined as the “diameter”.

<Evaluation results>
After 500 hours, the flexible organic EL device 40 of Comparative Example 1 had a DS size of 100 μm or more, and light emission shrinkage occurred. On the other hand, the flexible organic EL devices 40 of Examples 1 and 2 had a DS size of less than 100 μm, and no light emission shrinkage occurred. In the flexible organic EL devices 40 of Examples 1 and 2, the entire end face of the gas barrier film 10 (B) was covered with the sealant 5 containing the moisture absorbent 4, thereby suppressing moisture permeation from the end face direction. And the generation of light emitting shrinkage could be suppressed.

  According to the laminated film which concerns on this invention, it can utilize suitably for a flexible organic EL device, for example.

DESCRIPTION OF SYMBOLS 1 ... Base film 2 ... Gas barrier layer 3 ... Adhesive layer 4 ... Hygroscopic agent 5 ... Sealing agent 10, 10 (A), 10 (B) ... Gas barrier film 20 ... Laminated film 21 ... Organic EL element substrate 30 ... Sealing Stop film 40 ... Flexible organic EL device 50 ... Organic EL element

Claims (3)

In a laminated film in which two or more gas barrier films having a base film and a gas barrier layer formed on one surface of the base film are bonded via an adhesive,
The two or more gas barrier films comprise a gas barrier film (A) and a gas barrier film (B) having an outer dimension smaller than that of the gas barrier film (A).
The said gas barrier film (B) is laminated | stacked on the said gas barrier film (A) so that an outer periphery may be located inside the outer periphery of the said gas barrier film (A), The laminated | multilayer film characterized by the above-mentioned. A laminated film according to claim 1;
An organic EL element formed on the gas barrier film (B) of the laminated film;
A sealing agent for sealing the organic EL element;
A sealing film formed on the sealing agent,
An end surface of the gas barrier film (B) is covered with the sealing agent, and is a flexible organic EL device.   The flexible organic EL device according to claim 2, wherein the sealant contains a hygroscopic agent.