JP2007253588A - Barrier film substrate and organic electroluminescence device - Google Patents

Abstract

The present invention provides a barrier film substrate that has high water vapor barrier properties and does not peel off due to stress, and an organic electroluminescent device using the barrier film substrate.
A barrier film substrate having a plastic film and an alternating laminate composed of at least one organic layer and at least two inorganic layers on the plastic film, wherein the organic layer has an isocyanate group. A barrier film substrate characterized by comprising a polymer having the same, and an organic electroluminescence device using the same.
[Selection figure] None

Description

  TECHNICAL FIELD The present invention relates to a barrier film substrate, and more particularly to a laminated barrier film substrate suitable for various device substrates, and further to an organic electroluminescent element excellent in durability and flexibility using the barrier film substrate. (Organic EL device).

  Conventionally, a barrier film in which a metal oxide thin film such as aluminum oxide, magnesium oxide, silicon oxide or the like is formed on the surface of a plastic film is used for wrapping articles, food, Widely used in packaging applications to prevent alteration of industrial products and pharmaceuticals

  In recent years, in the fields of liquid crystal display elements and organic electroluminescent elements (organic EL elements), plastic film substrates have begun to be used instead of heavy and fragile glass substrates. Since the plastic film substrate can be applied to a roll-to-roll method, it is advantageous in terms of cost. However, there is a problem that the plastic film substrate is inferior in water vapor barrier property as compared with the glass substrate. For this reason, when a plastic film substrate is used for a liquid crystal display element, water vapor enters the liquid crystal cell and a display defect occurs.

In order to solve this problem, it is known to use a barrier film substrate in which a metal oxide thin film is formed on a plastic film. Known barrier film substrates include those obtained by vapor-depositing silicon oxide on a plastic film (for example, see Patent Document 1) and those obtained by vapor-depositing aluminum oxide (for example, see Patent Document 2). Also has a barrier property such that water vapor permeability is about 1 g / m ² · day.

However, a substrate for use in an organic EL element is required to have a barrier property such that the water vapor transmission rate is less than 0.01 g / m ² · day. As a means for meeting such demands, a technique has been proposed in which a barrier film having an alternately laminated structure of organic layers / inorganic layers is produced by a vacuum deposition method (see, for example, Non-Patent Document 1).

  However, the barrier film having the alternately laminated structure of the organic layer / inorganic layer has a problem in adhesion between layers, and there is a problem that the barrier film is peeled off due to deformation such as bending. In addition, when an organic EL device manufactured using a barrier film substrate that is easily peeled is stored under wet heat conditions, the original barrier property is not exhibited by peeling, and a non-light emitting failure called a dark spot occurs. For this reason, development of a barrier film substrate that has high water vapor barrier properties and does not peel off due to stress has been desired.

Japanese Patent Publication No. 53-12, 953 (pages 1 to 3) JP-A-58-217,344 (pages 1 to 4) “Thin Solid Films” (1996), P. by Affinito et al. 290-291 (pages 63-67)

  The first object of the present invention is to provide a barrier film substrate that has a high water vapor barrier property and does not peel off due to stress. The second object of the present invention is to provide an organic electroluminescent device using the barrier film substrate.

[1] A barrier film substrate having a plastic film and an alternate laminate comprising at least one organic layer and at least two inorganic layers on the plastic film, wherein the organic layer has an isocyanate group A barrier film substrate comprising a polymer.

[2] The barrier film substrate according to [1], wherein the polymer having an isocyanate group has a structure derived from a vinyl monomer represented by the following general formula (1).

〔一般式（１）中、Ｒ¹¹は水素原子またはアルキル基を表し、Ｌ¹は連結基を表し、ａ１１およびａ１２はそれぞれ独立に１〜４の整数を表す。〕

[In General Formula (1), R ¹¹ represents a hydrogen atom or an alkyl group, L ¹ represents a linking group, and a11 and a12 each independently represents an integer of 1 to 4. ]

[3] The barrier film substrate according to [2], wherein R ¹¹ in the general formula (1) is a hydrogen atom.

[4] The organic layer includes a polymer having a structure derived from a vinyl monomer having at least one hydroxyl group and at least one acrylate or methacrylate group in the molecule. ] The barrier film board | substrate in any one of.

[5] The vinyl monomer unit having at least one hydroxyl group and at least one acrylate or methacrylate group in the molecule is a vinyl monomer unit represented by the following general formula (2) [4] ] The barrier property film substrate as described in.

〔一般式（２）中、Ｒ²¹は水素原子またはアルキル基を表し、Ｌ²は連結基を表し、ａ２１およびａ２２はそれぞれ独立に１〜４の整数を表す。〕

[In General Formula (2), R ²¹ represents a hydrogen atom or an alkyl group, L ² represents a linking group, and a ^{21 and a 22} each independently represent an integer of 1 to 4. ]

[6] The barrier according to any one of [1] to [5], wherein the at least one inorganic layer contains an oxide, nitride, or oxynitride of an element selected from Si and Al. Film substrate.

[7] The barrier film substrate according to any one of [1] to [5], which has a water vapor transmission rate of 0.01 g / m ² · day or less at 40 ° C. and a relative humidity of 90%.

[8] The barrier film substrate according to any one of [1] to [6], wherein the plastic film has a glass transition temperature of 200 ° C. or higher.

[9] An organic electroluminescence device using the barrier film substrate according to any one of [1] to [7].

  According to the present invention, it is possible to provide a barrier film substrate that has a high water vapor barrier property and does not peel off due to stress, and an organic electroluminescent device using the barrier film substrate.

  First, the barrier film substrate of the present invention will be described in detail below. The description of the constituent elements described below may be made based on typical embodiments of the present invention, but the present invention is not limited to such embodiments. In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

<Barrier film substrate>
The barrier film substrate of the present invention is a film substrate having a plastic film and an alternate laminate comprising at least one organic layer and at least two inorganic layers on the plastic film. As a layer structure of the alternately laminated body, for example, the first inorganic layer, the organic layer, and the second inorganic layer are deposited in this order from the plastic film side. In the present invention, another layer may be inserted between the plastic film and the first inorganic layer. Further, another layer may be present on the second inorganic layer.

The barrier film substrate of the present invention is preferably a film substrate having an alternating laminate of an inorganic layer and an organic layer on a plastic film. As the layer structure, the first inorganic layer, the first organic layer, and the second inorganic layer are deposited in this order from the plastic film side. Further, the second organic layer, the third inorganic layer, The third organic layer, the fourth inorganic layer,..., And the nth inorganic layer may be repeatedly laminated.
Alternatively, the first organic layer, the first inorganic layer, the second organic layer, and the second inorganic layer are deposited in this order from the plastic film side, and the third organic layer and the third inorganic layer are further deposited thereon. , The fourth organic layer, the fourth inorganic layer,..., And the nth inorganic layer may be repeatedly laminated. The uppermost layer of the alternating laminate may be an inorganic layer or an organic layer.
In addition, if necessary, another functional layer may be inserted between the plastic film and the alternate laminate, on the alternate laminate, or on the back surface of the plastic film. Another functional layer to be inserted may be a single layer or multiple layers.

The components of the present invention will be described in detail below.
(Inorganic layer)
The inorganic layer in this invention means the layer comprised with an inorganic material. The inorganic layer is a thin film having a dense structure capable of suppressing the permeation of gas molecules. Examples of the inorganic layer include a thin film (metal compound thin film) made of a metal compound. As a method for forming the inorganic layer, any method can be used as long as it can form a target thin film. For example, a sputtering method, a vacuum deposition method, an ion plating method, a plasma CVD method, etc. are suitable. The method can be adopted.
The component contained in the inorganic layer is not particularly limited as long as it satisfies the above performance, but for example, one or more selected from Si, Al, In, Sn, Zn, Ti, Cu, Ce, Ta, and the like An oxide containing an element, nitride, oxynitride, or the like can be used. Among these, an oxide, nitride or oxynitride of an element selected from Si, Al, In, Sn, Zn and Ti is preferable, and a metal oxide, nitride or oxynitride of an element selected from Si and Al is particularly preferable. Things are preferred. These may contain other elements as secondary components.

  The thickness of the inorganic layer is not particularly limited, but if the thickness is too thick, cracks due to bending stress occur, and if the thickness is too thin, the film is distributed in an island shape without forming a layer. Tend to be. Therefore, the thickness of each inorganic layer is preferably in the range of 5 nm to 500 nm, and more preferably 10 nm to 200 nm. The two or more inorganic layers may each have the same composition or different compositions.

(Organic layer)
The organic layer in the barrier film substrate of the present invention contains a polymer having an isocyanate group (hereinafter abbreviated as “polymer in the present invention”) as a main component. The polymer in the present invention is synthesized by radical polymerization of a monomer having an isocyanate group (hereinafter abbreviated as “monomer in the present invention”) alone or mixed with another monomer. The polymer in the present invention preferably has a structure derived from a monomer represented by the following general formula (1).

〔一般式（１）中、Ｒ¹¹は水素原子またはアルキル基を表し、Ｌ¹は連結基を表し、ａ１１およびａ１２はそれぞれ独立に１〜４の整数を表す。〕

[In General Formula (1), R ¹¹ represents a hydrogen atom or an alkyl group, L ¹ represents a linking group, and a11 and a12 each independently represents an integer of 1 to 4. ]

In the general formula (1), R ¹¹ represents a hydrogen atom or an alkyl group (for example, a methyl group, an ethyl group, a butyl group, etc.). Among these, R ¹¹ is preferably a hydrogen atom or a methyl group, and more preferably a hydrogen atom. L ¹ represents a divalent to pentavalent linking group. Examples of divalent L ¹ include a single bond, an oxygen atom, a sulfur atom, a carbonyl group, an alkylene group (eg, methylene, ethylene, propylene, butylene, pentylene, hexylene, etc.), an arylene group (eg, phenylene, naphthylene, etc.), or And a group in which a plurality of these divalent groups are bonded in series (for example, alkylene arylene, alkyleneoxy, alkyleneoxyalkylene, alkyleneoxycarbonyl, aryleneoxycarbonyl, carboxyalkyleneoxy, carboxyalkyleneoxycarbonyl, etc.). As 3-5 monovalent examples of L ¹ include a linking group to generate pull out 1-3 arbitrary hydrogen atom from the example of the divalent L ^1. The sum of a11 and a12 varies depending on the valence of the linking group, 2 for divalent linking groups, 3 for trivalent linking groups, 4 for tetravalent linking groups. 5 represents a pentavalent linking group, respectively. R ¹¹ and L ¹ may be bonded to each other to form a ring.

When the polymer in the present invention is a copolymer, the other monomer to be mixed is also a vinyl monomer. Preferred vinyl monomers include acrylates, methacrylates, styrenes, vinyl acylates, acrylamides and the like. Of these, acrylate and methacrylate are particularly preferable.
Specific examples (IC-1 to IC14) of the vinyl monomer unit represented by the general formula (1) are shown below, but the vinyl monomer unit of the general formula (1) that can be used in the present invention is not limited thereto.

  In the present invention, the content of the structure derived from the monomer represented by the general formula (1) contained in the organic layer is preferably 0.01% by mass to 50% by mass of the organic layer, The content is more preferably from 20% by mass to 20% by mass, and particularly preferably from 0.01% by mass to 10% by mass.

  Examples of the method for forming the organic layer include a normal bar coating method or a vacuum film forming method. Although there is no restriction | limiting in particular as a vacuum film-forming method, Film-forming methods, such as vapor deposition and plasma CVD, are preferable, and the resistance heating vapor deposition method which is easy to control a film-forming rate is more preferable. In the present invention, an organic polymer layer is formed by polymerizing an organic substance during or after film formation. The method for polymerizing the organic substance is not particularly limited, and heat polymerization, light (ultraviolet ray, visible light) polymerization, electron beam polymerization, plasma polymerization, or a combination thereof is preferably used. When performing heat polymerization, the plastic film used as a base material needs to have appropriate heat resistance. In this case, at least the Tg (glass transition temperature) of the plastic film needs to be higher than the heating temperature. When carrying out photopolymerization, a photopolymerization initiator is used in combination. The photopolymerization initiator is deposited simultaneously with the monomer.

  Post polymerization may be performed to convert unreacted monomer to polymer. Post polymerization is performed using heating, light (ultraviolet ray, visible light) irradiation, electron beam irradiation, plasma irradiation, and a combination thereof. Post polymerization may be performed immediately after the organic layer is installed, or may be performed after all the layers are installed. When a plurality of organic layers are installed, post polymerization may be performed for each organic layer installation.

  The film thickness of the organic layer is not particularly limited. However, if it is too thin, it is difficult to obtain film thickness uniformity, and if it is too thick, cracks are generated due to external force and the barrier property is lowered. From this viewpoint, the thickness of the adjacent organic layer is preferably 10 nm to 2000 nm, more preferably 20 nm to 1000 nm, and most preferably 50 nm to 500 nm.

  In addition, the method of generating a monomer unit in the present invention by applying some energy before and after the polymerization reaction by performing a polymerization reaction using a monomer precursor (precursor) in the present invention is one of the preferred embodiments of the present invention. . Examples of the energy application method for generating the monomer unit in the present invention from the monomer precursor in the present invention include heating, ultraviolet irradiation, X-ray irradiation, and electron beam irradiation.

  In the said precursor, the compound by which the isocyanate group is protected by the protective group is preferable. Specific examples of the precursor (ICP-1 to ICP-9) are shown below, but the precursor that can be used in the present invention is not limited thereto.

  In the polymer of the present invention, a polymer having a structure derived from a vinyl monomer having a nucleophilic functional group, preferably at least one hydroxyl group and at least one acrylate group or methacrylate group may be used in combination. In that case, a vinyl polymer represented by the following general formula (2) is desirable.

〔一般式（２）中、Ｒ²¹は水素原子またはアルキル基を、Ｌ²は連結基を、ａ２１およびａ２２はそれぞれ独立に１〜４の整数を表す。］

[In General Formula (2), R ²¹ represents a hydrogen atom or an alkyl group, L ² represents a linking group, and a ^{21 and a 22} each independently represent an integer of 1 to 4. ]

In the general formula (2), R ²¹ is a hydrogen atom or an alkyl group (for example, a methyl group, an ethyl group, a butyl group, etc.). Among these, a hydrogen atom or a methyl group is preferable, and a hydrogen atom is more preferable. L ² has the same meaning as L ¹ in the general formula (1). Moreover, a21 and a22 in General formula (2) are synonymous with a11 and a12 in General formula (1). Specific examples (HA-1 to HA-7) of vinyl monomer units represented by the general formula (2) are shown below, but the vinyl monomers of the general formula (2) that can be used in the present invention are limited to these. It is not something. In the following specific examples, n represents an integer of 2 or more.

  In the present invention, the content of the structure derived from the monomer represented by the general formula (2) contained in the organic layer is preferably 0.01% by mass to 50% by mass of the organic layer, More preferably, the content is from 20% by mass to 20% by mass, and particularly preferably from 0.01% by mass to 10% by mass.

(Plastic film)
The plastic film used for the barrier film substrate of the present invention is not particularly limited as long as it is a film that can hold each of the above layers, and can be appropriately selected according to the purpose of use. Specific examples of the plastic film include polyester, methacrylic resin, methacrylic acid-maleic acid copolymer, polystyrene, transparent fluororesin, polyimide, fluorinated polyimide, polyamide, polyamideimide, polyetherimide, cellulose acylate, and polyurethane. And thermoplastic resins such as polyetheretherketone, polycarbonate, alicyclic polyolefin, polyarylate, polyethersulfone, polysulfone, fluorene ring-modified polycarbonate, alicycle-modified polycarbonate, fluorene ring-modified polyester, and acryloyl compound.

  Among these resins, a resin having a glass transition temperature (Tg) of 120 ° C. or higher is preferable, 200 ° C. or higher is more preferable, and 250 ° C. or higher is further preferable. Specific examples (abbreviations in parentheses: numbers indicate Tg) are polyesters, particularly polyethyl naphthalate (PEN: 121 ° C.), polyarylate (PAr: 210 ° C.), polyether sulfone (PES: 220). ), Fluorene ring-modified polycarbonate (BCF-PC: compound of Example 4 of JP 2000-227603 A: 225 ° C.), alicyclic modified polycarbonate (IP-PC: Example 5 of JP 2000-227603 A). Compound: 205 ° C.), fluorene ring-modified polyester (compound used in films 1 to 5 described in Example 1 of JP 2002-145998 A: 334 to 365 ° C.), acryloyl compound (JP 2002-80616). No. 1 in the publication No .: a film made of a compound such as 300 ° C or higher) It is.

(Hygroscopic layer)
The barrier film substrate of the present invention may have a hygroscopic layer. As a preferable example of the hygroscopic layer, a layer composed of an alkaline earth metal monoxide can be given. Examples of the alkaline earth metal contained in the alkaline earth metal monoxide include Be, Mg, Ca, Sr, and Ba. In the present invention, any alkaline earth metal can be used, but Ca, Sr, and Ba are preferable in consideration of cost and hygroscopicity.

(Primer layer)
In the barrier film substrate of the present invention, a known primer layer can be placed on a plastic film. Examples of the primer layer include a resin layer such as an acrylic resin, an epoxy resin, a urethane resin, and a silicone resin, an organic-inorganic hybrid layer formed by a sol-gel reaction in the presence of a hydrophilic resin, an inorganic vapor deposition layer, or a dense sol-gel method. An inorganic layer can be mentioned.

(Protective layer)
The barrier film substrate of the present invention may have a protective layer. In particular, it is preferable to provide a protective layer on the back surface of the substrate. Examples of the polymer used for the protective layer include water-soluble polymers, cellulose acylates, latex polymers, water-soluble polyesters, and the like. Examples of the water-soluble polymer include gelatin, gelatin derivatives, casein, agar, sodium alginate, starch, polyvinyl alcohol, polyacrylic acid copolymer, maleic anhydride copolymer and the like. Examples of the cellulose acylate include carboxymethyl cellulose and hydroxyethyl cellulose. Examples of the latex polymer include a vinyl chloride-containing copolymer, a vinylidene chloride-containing copolymer, an acrylate ester-containing copolymer, a vinyl acetate-containing copolymer, and a butadiene-containing copolymer.

The protective layer can contain inorganic or organic fine particles as a matting agent to such an extent that the transparency of the barrier film substrate is not substantially impaired. Silica (SiO ₂ ), titanium dioxide (TiO ₂ ), calcium carbonate, magnesium carbonate and the like can be used as the inorganic fine particle matting agent. Examples of the organic fine particle matting agent include polymethyl methacrylate, cellulose acetate propionate, polystyrene, a treatment solution-soluble one described in US Pat. No. 4,142,894, US Pat. The polymers described in 396, 706 can be used. These fine particle matting agents preferably have an average particle size of 0.01 to 10 μm. More preferably, it is 0.05-5 micrometers. Moreover, the content is preferably 0.5 to 600 mg / m ² , more preferably 1 to 400 mg / m ² .

  The protective layer is formed by a generally well-known coating method such as dip coating, air knife coating, curtain coating, roller coating, wire bar coating, gravure coating, slide coating, or US Pat. , 681,294 specification, and can be applied by an extrusion coating method using a hopper.

(Antistatic layer)
The barrier film substrate of the present invention may have an antistatic layer (conductive layer). The antistatic layer is preferably formed on the back surface (the surface on which the barrier layer is not formed) of the barrier film substrate. The antistatic layer imparts a function of preventing charging during handling of the gas barrier film. Specifically, the antistatic layer is formed by providing a layer containing an ion conductive substance or conductive fine particles.
Here, the ion conductive substance is a substance that shows electric conductivity and contains ions that are carriers for carrying electricity, and examples include ionic polymer compounds. Examples of the ionic polymer compound include anionic polymer compounds such as those described in JP-B-49-23828, JP-B-49-23827, and JP-B-47-28937; In the main chain as seen in JP-A-50-54772, JP-B-59-14735, JP-B-57-18175, JP-B-57-18176, JP-B-57-56059, etc. Ionene type polymer having a dissociation group at: JP-B 53-13223, JP-B 57-15376, JP-B 53-45231, JP-B 55-145783, JP-B 55-65950, JP Japanese Patent Publication No. 55-67746, Japanese Patent Publication No. 57-11342, Japanese Patent Publication No. 57-19735, Japanese Patent Publication No. 58-56858 JP 61-27853 and JP-as seen in JP-B-62-9346, can be mentioned cationic pendant polymers having a cationic dissociative group in the side chain.

Examples of metal oxides that are conductive fine particles include ZnO, TiO ₂ , SnO ₂ , Al ₂ O ₃ , In ₂ O ₃ , SiO ₂ , MgO, BaO, MoO ₂ , V ₂ O _5, etc. Complex oxides are preferred, with ZnO, TiO ₂ and SnO ₂ being particularly preferred. Examples of containing different atoms include, for example, addition of Al and In to ZnO, addition of Nb and Ta to TiO ₂ , and addition of Sb, Nb and halogen elements to SnO ₂ . Addition is effective. The amount of these different atoms added is preferably in the range of 0.01 to 25 mol%, particularly preferably in the range of 0.1 to 15 mol%.

(Other functional layers)
The barrier film substrate of the present invention may be provided with a smoothing layer, an adhesion improving layer, a light shielding layer, an antireflection layer, a hard coat layer and the like as required.

Further, the water vapor permeability of the barrier film substrate of the present invention measured at 40 ° C. and 90% relative humidity is preferably 0.01 g / m ² · day or less, and is 0.001 g / m ² · day or less. More preferably. If the gas barrier performance is within the above range, for example, when used in an organic EL display device or a liquid crystal display device, it is preferable that deterioration of the EL element due to water vapor and oxygen can be substantially eliminated.

  Next, an organic EL element using the barrier film substrate of the present invention (hereinafter referred to as “organic EL element of the present invention”) will be described.

<Organic EL device>
The organic EL device of the present invention has a cathode and an anode on a substrate, and has an organic compound layer including an organic light emitting layer (hereinafter sometimes simply referred to as “light emitting layer”) between both electrodes. In view of the properties of the light emitting element, at least one of the anode and the cathode is preferably transparent.
As an aspect of lamination of the organic compound layer in the present invention, an aspect in which a hole transport layer, a light emitting layer, and an electron transport layer are laminated in this order from the anode side is preferable. Furthermore, a charge blocking layer or the like may be provided between the hole transport layer and the light-emitting layer, or between the light-emitting layer and the electron transport layer. A hole injection layer may be provided between the anode and the hole transport layer, and an electron injection layer may be provided between the cathode and the electron transport layer. Each layer may be divided into a plurality of secondary layers.

(anode)
The anode usually has a function as an electrode for supplying holes to the organic compound layer, and there is no particular limitation on the shape, structure, size, etc., depending on the use and purpose of the light-emitting element. , Can be appropriately selected from known electrode materials. As described above, the anode is usually provided as a transparent anode.

  Suitable examples of the material for the anode include metals, alloys, metal oxides, conductive compounds, and mixtures thereof. Specific examples of the anode material include conductive metals such as tin oxide doped with antimony and fluorine (ATO, FTO), tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO). Metals such as oxides, gold, silver, chromium and nickel, and mixtures or laminates of these metals and conductive metal oxides, inorganic conductive materials such as copper iodide and copper sulfide, polyaniline, polythiophene and polypyrrole Organic conductive materials, and laminates of these with ITO. Among these, conductive metal oxides are preferable, and ITO is particularly preferable from the viewpoints of productivity, high conductivity, transparency, and the like.

  The anode is composed of, for example, a wet method such as a printing method and a coating method, a physical method such as a vacuum deposition method, a sputtering method, and an ion plating method, and a chemical method such as a CVD and a plasma CVD method. It can be formed on the substrate according to a method appropriately selected in consideration of suitability with the material to be processed. For example, when ITO is selected as the anode material, the anode can be formed according to a direct current or high frequency sputtering method, a vacuum deposition method, an ion plating method, or the like.

  In the organic electroluminescent element of the present invention, the formation position of the anode is not particularly limited and can be appropriately selected according to the use and purpose of the light emitting element. Is preferably formed on the substrate. In this case, the anode may be formed on the entire one surface of the substrate, or may be formed on a part thereof. The patterning for forming the anode may be performed by chemical etching such as photolithography, or may be performed by physical etching such as laser, or vacuum deposition or sputtering with a mask overlapped. It may be performed by a lift-off method or a printing method. The thickness of the anode can be appropriately selected depending on the material constituting the anode and cannot be generally defined, but is usually about 10 nm to 50 μm, and preferably 50 nm to 20 μm.

The resistance value of the anode is preferably 10 ³ Ω / □ or less, and more preferably 10 ² Ω / □ or less. When the anode is transparent, it may be colorless and transparent or colored and transparent. In order to take out light emission from the transparent anode side, the transmittance is preferably 60% or more, and more preferably 70% or more. The transparent anode is described in detail in the book “New Development of Transparent Electrode Films” published by CMC (1999), supervised by Yutaka Sawada, and the matters described here can be applied to the present invention. In the case of using a plastic substrate having low heat resistance, a transparent anode formed using ITO or IZO at a low temperature of 150 ° C. or lower is preferable.

(cathode)
The cathode usually has a function as an electrode for injecting electrons into the organic compound layer, and there is no particular limitation on the shape, structure, size, etc., depending on the use and purpose of the light-emitting element, It can select suitably from well-known electrode materials. Examples of the material constituting the cathode include metals, alloys, metal oxides, electrically conductive compounds, and mixtures thereof. Specific examples include alkali metals (eg, Li, Na, K, Cs, etc.), alkaline earth metals (eg, Mg, Ca, etc.), gold, silver, lead, aluminum, sodium-potassium alloys, lithium-aluminum alloys, magnesium. -Rare earth metals such as silver alloys, indium, ytterbium, and the like. These may be used alone, but two or more can be suitably used in combination from the viewpoint of achieving both stability and electron injection.

Among these, as a material constituting the cathode, an alkali metal or an alkaline earth metal is preferable from the viewpoint of electron injecting property, and a material mainly composed of aluminum is preferable from the viewpoint of excellent storage stability.
The material mainly composed of aluminum is aluminum alone, an alloy of aluminum and 0.01 to 10% by mass of alkali metal or alkaline earth metal, or a mixture thereof (for example, lithium-aluminum alloy, magnesium-aluminum alloy). Say. The materials for the cathode are described in detail in JP-A-2-15595 and JP-A-5-121172, and the materials described in these public relations can also be applied in the present invention.

  There is no restriction | limiting in particular about the formation method of a cathode, According to a well-known method, it can carry out. For example, the cathode described above is configured from a wet method such as a printing method or a coating method, a physical method such as a vacuum deposition method, a sputtering method, or an ion plating method, or a chemical method such as CVD or plasma CVD method. It can be formed according to a method appropriately selected in consideration of suitability with the material. For example, when a metal or the like is selected as the cathode material, one or more of them can be simultaneously or sequentially performed according to a sputtering method or the like. Patterning when forming the cathode may be performed by chemical etching such as photolithography, physical etching by laser, or the like, or by vacuum deposition or sputtering with the mask overlaid. It may be performed by a lift-off method or a printing method.

In the present invention, the cathode formation position is not particularly limited, and may be formed on the entire organic compound layer or a part thereof. A dielectric layer made of an alkali metal or alkaline earth metal fluoride or oxide may be inserted between the cathode and the organic compound layer with a thickness of 0.1 to 5 nm. This dielectric layer can also be regarded as a kind of electron injection layer. The dielectric layer can be formed by, for example, a vacuum deposition method, a sputtering method, an ion plating method, or the like. The thickness of the cathode can be appropriately selected depending on the material constituting the cathode and cannot be generally defined, but is usually about 10 nm to 5 μm, and preferably 50 nm to 1 μm.
Further, the cathode may be transparent or opaque. The transparent cathode can be formed by depositing a thin cathode material to a thickness of 1 to 10 nm and further laminating a transparent conductive material such as ITO or IZO.

(Organic compound layer)
The organic compound layer in the present invention will be described.
The organic electroluminescent element of the present invention has at least one organic compound layer including a light emitting layer, and the organic compound layer other than the organic light emitting layer includes a hole transport layer, an electron transport layer as described above. , Charge blocking layer, hole injection layer, electron injection layer and the like.

-Formation of organic compound layer-
In the organic electroluminescent element of the present invention, each layer constituting the organic compound layer can be suitably formed by any of a dry film forming method such as a vapor deposition method and a sputtering method, a transfer method, and a printing method.

-Organic light emitting layer-
The organic light-emitting layer receives holes from the anode, the hole injection layer, or the hole transport layer when an electric field is applied, and receives electrons from the cathode, the electron injection layer, or the electron transport layer, and recombines the holes and electrons. It is a layer having a function of providing light and emitting light. The light emitting layer in the present invention may be composed only of a light emitting material, or may be a mixed layer of a host material and a light emitting material. The light emitting material may be a fluorescent light emitting material or a phosphorescent light emitting material, and the dopant may be one type or two or more types. The host material is preferably a charge transport material. The host material may be one kind or two or more kinds, and examples thereof include a configuration in which an electron transporting host material and a hole transporting host material are mixed. Furthermore, the light emitting layer may include a material that does not have charge transporting properties and does not emit light. Further, the light emitting layer may be a single layer or two or more layers, and each layer may emit light in different emission colors.

  Examples of fluorescent materials that can be used in the present invention include, for example, benzoxazole derivatives, benzimidazole derivatives, benzothiazole derivatives, styrylbenzene derivatives, polyphenyl derivatives, diphenylbutadiene derivatives, tetraphenylbutadiene derivatives, naphthalimide derivatives, coumarin derivatives. , Condensed aromatic compounds, perinone derivatives, oxadiazole derivatives, oxazine derivatives, aldazine derivatives, pyralidine derivatives, cyclopentadiene derivatives, bisstyrylanthracene derivatives, quinacridone derivatives, pyrrolopyridine derivatives, thiadiazolopyridine derivatives, cyclopentadiene derivatives, styryl Of amine derivatives, diketopyrrolopyrrole derivatives, aromatic dimethylidin compounds, metal complexes of 8-quinolinol derivatives and pyromethene derivatives And various metal complexes typified by metal complex, polythiophene, polyphenylene, polyphenylene vinylene polymer compounds include compounds such as organic silane derivatives.

  Examples of the phosphorescent material that can be used in the present invention include a complex containing a transition metal atom or a lanthanoid atom. Although it does not specifically limit as a transition metal atom, Preferably, ruthenium, rhodium, palladium, tungsten, rhenium, osmium, iridium, and platinum are mentioned, More preferably, they are rhenium, iridium, and platinum. Examples of lanthanoid atoms include lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. Among these lanthanoid atoms, neodymium, europium, and gadolinium are preferable.

  As a ligand of the complex, for example, G. Wilkinson et al., Comprehensive Coordination Chemistry, published in 1987 by Pergamon Press, H. Examples include ligands described in Yersin, “Photochemistry and Photophysics of Coordination Compounds” published by Springer-Verlag, 1987, and Akio Yamamoto, “Organic Metal Chemistry: Fundamentals and Applications”, published by Soukabo, 1982. . Specific ligands are preferably halogen ligands (preferably chlorine ligands), nitrogen-containing heterocyclic ligands (eg, phenylpyridine, benzoquinoline, quinolinol, bipyridyl, phenanthroline, etc.), diketones Ligand (for example, acetylacetone), carboxylic acid ligand (for example, acetic acid ligand), carbon monoxide ligand, isonitrile ligand, cyano ligand, more preferably nitrogen-containing Heterocyclic ligand. The complex may have one transition metal atom in the compound, or may be a so-called binuclear complex having two or more. Different metal atoms may be contained at the same time.

  The phosphorescent material is preferably contained in the light emitting layer in an amount of 0.1 to 40% by mass, and more preferably 0.5 to 20% by mass. Examples of the host material contained in the light emitting layer in the present invention include those having a carbazole skeleton, those having a diarylamine skeleton, those having a pyridine skeleton, those having a pyrazine skeleton, those having a triazine skeleton, and aryl. Examples thereof include materials having a silane skeleton and materials exemplified in the sections of a hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer described later. Although the thickness of a light emitting layer is not specifically limited, Usually, it is preferable that they are 1 nm-500 nm, it is more preferable that they are 5 nm-200 nm, and it is further more preferable that they are 10 nm-100 nm.

-Hole injection layer, hole transport layer-
The hole injection layer and the hole transport layer are layers having a function of receiving holes from the anode or the anode side and transporting them to the cathode side. Specifically, the hole injection layer and the hole transport layer are carbazole derivatives, triazole derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamines. Derivatives, amino-substituted chalcone derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aromatic tertiary amine compounds, styrylamine compounds, aromatic dimethylidin compounds, porphyrin compounds, organosilane derivatives, carbon , Etc. are preferable. The thicknesses of the hole injection layer and the hole transport layer are each preferably 500 nm or less from the viewpoint of lowering the driving voltage.

  The thickness of the hole transport layer is preferably 1 nm to 500 nm, more preferably 5 nm to 200 nm, and even more preferably 10 nm to 100 nm. In addition, the thickness of the hole injection layer is preferably 0.1 nm to 200 nm, more preferably 0.5 nm to 100 nm, and further preferably 1 nm to 100 nm. The hole injection layer and the hole transport layer may have a single-layer structure composed of one or more of the above-described materials, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions. .

-Electron injection layer, electron transport layer-
The electron injection layer and the electron transport layer are layers having a function of receiving electrons from the cathode or the cathode side and transporting them to the anode side. Specifically, the electron injection layer and the electron transport layer are triazole derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, fluorenone derivatives, anthraquinodimethane derivatives, anthrone derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, Carbodiimide derivatives, fluorenylidenemethane derivatives, distyrylpyrazine derivatives, aromatic tetracarboxylic anhydrides such as naphthalene and perylene, phthalocyanine derivatives, metal complexes of 8-quinolinol derivatives, metal phthalocyanines, benzoxazoles and benzothiazoles as ligands It is preferably a layer containing various metal complexes typified by metal complexes, organosilane derivatives, and the like.

  The thicknesses of the electron injection layer and the electron transport layer are each preferably 50 nm or less from the viewpoint of lowering the driving voltage. The thickness of the electron transport layer is preferably 1 nm to 500 nm, more preferably 5 nm to 200 nm, and even more preferably 10 nm to 100 nm. In addition, the thickness of the electron injection layer is preferably 0.1 nm to 200 nm, more preferably 0.2 nm to 100 nm, and further preferably 0.5 nm to 50 nm. The electron injection layer and the electron transport layer may have a single layer structure composed of one or more of the above-described materials, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions.

-Hole blocking layer-
The hole blocking layer is a layer having a function of preventing holes transported from the anode side to the light emitting layer from passing through to the cathode side. In the present invention, a hole blocking layer can be provided as an organic compound layer adjacent to the light emitting layer on the cathode side. Examples of the organic compound constituting the hole blocking layer include aluminum complexes such as BAlq, triazole derivatives, phenanthroline derivatives such as BCP, and the like. The thickness of the hole blocking layer is preferably 1 nm to 500 nm, more preferably 5 nm to 200 nm, and even more preferably 10 nm to 100 nm. The hole blocking layer may have a single layer structure composed of one or more of the above-described materials, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions.

(Protective layer)
In the present invention, the entire organic EL element may be protected by a protective layer.
As a material contained in the protective layer, a material having a planarizing action and a material having a function of preventing moisture and oxygen from entering the element are preferable. Specific examples, In, Sn, Pb, Au , Cu, Ag, Al, Ti, a metal such as _{Ni, MgO, SiO, SiO 2,} Al 2 O 3, GeO, NiO, CaO, BaO, Fe 2 O 3 , Y ₂ O _3, TiO ₂ and metal oxides, metal nitrides such as SiN _x, SiN _x O _y or the like of metallic _{oxynitride, MgF 2, LiF, AlF 3} , CaF 2 , etc. of the metal fluoride, polyethylene , Polypropylene, polymethyl methacrylate, polyimide, polyurea, polytetrafluoroethylene, polychlorotrifluoroethylene, polydichlorodifluoroethylene, copolymer of chlorotrifluoroethylene and dichlorodifluoroethylene, tetrafluoroethylene and at least one comonomer A copolymer obtained by copolymerizing a monomer mixture containing a cyclic structure in the copolymer main chain Fluorine-containing copolymer having 1% by weight of the water absorbing water absorption material, water absorption of 0.1% or less of moisture-proof material, and the like. Of these, metal oxides, nitrides, and nitride oxides are preferable, and silicon oxides, nitrides, and nitride oxides are particularly preferable.

  The method for forming the protective layer is not particularly limited, and for example, vacuum deposition, sputtering, reactive sputtering, MBE (molecular beam epitaxy), cluster ion beam, ion plating, plasma polymerization (high frequency) Excited ion plating method), plasma CVD method, laser CVD method, thermal CVD method, gas source CVD method, vacuum ultraviolet CVD method, coating method, printing method, transfer method can be applied. In the present invention, a protective layer may be used as the conductive layer.

(Sealing)
Furthermore, the organic electroluminescent element of this invention may seal the whole element using a sealing container. Further, a moisture absorbent or an inert liquid may be enclosed in a space between the sealing container and the light emitting element. Although it does not specifically limit as a moisture absorber, For example, barium oxide, sodium oxide, potassium oxide, calcium oxide, sodium sulfate, calcium sulfate, magnesium sulfate, phosphorus pentoxide, calcium chloride, magnesium chloride, copper chloride Cesium fluoride, niobium fluoride, calcium bromide, vanadium bromide, molecular sieve, zeolite, magnesium oxide and the like. The inert liquid is not particularly limited, and examples thereof include fluorinated solvents such as paraffins, liquid paraffins, perfluoroalkanes, perfluoroamines, perfluoroethers, chlorinated solvents, and silicone oils. It is done.

  As another sealing method, a so-called solid sealing method may be used. The solid sealing method is a method in which a protective layer is formed on an organic EL element, and then an adhesive layer and a barrier support layer are stacked and cured. Although there is no restriction | limiting in particular in an adhesive agent, A thermosetting epoxy resin, a photocurable acrylate resin, etc. are illustrated. The barrier support may be glass or the barrier plastic substrate of the present invention.

  As another sealing method, a so-called film sealing method may be used. The film sealing method is a method of providing an alternating laminate of an inorganic layer and an organic layer on an organic EL element. Before providing the alternate laminate, the organic EL element may be covered with a protective layer.

  The organic electroluminescence device of the present invention emits light by applying a direct current (which may include an alternating current component as necessary) voltage (usually 2 to 15 volts) or a direct current between the anode and the cathode. Obtainable. The driving method of the organic electroluminescence device of the present invention is described in JP-A-2-148687, JP-A-6-301355, JP-A-5-29080, JP-A-7-134558, JP-A-8-234585, The driving methods described in Japanese Patent No. 8-24047, Japanese Patent No. 2784615, US Pat. Nos. 5,828,429, 6023308, and the like can be applied.

  The features of the present invention will be described more specifically with reference to the following examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Accordingly, the scope of the present invention should not be construed as being limited by the specific examples shown below.

[Example 1]
Barrier film substrates (Sample BF-1 to Sample BF-5) in which a first inorganic layer, a first organic layer, and a second inorganic layer were provided on a plastic film were prepared according to the following procedure. Details of each sample are as described in Table 1.

(1) Production of Plastic Film Resin A was dissolved in a dichloromethane solution so as to have a concentration of 15% by mass, and the solution was cast on a stainless steel band by a die coating method. Next, the first film was peeled off from the band and dried until the residual solvent concentration became 0.08% by mass. After drying, both ends of the first film were trimmed, knurled and then wound up to prepare a substrate film PE-1 having a thickness of 100 μm. The glass transition temperature (Tg) of PE-1 was 355 ° C. (DMA method).

(2) Formation of barrier film substrate (2-1) Formation of first inorganic layer An inorganic layer (aluminum oxide) was formed on the base film PE-1 using a sputtering apparatus. Aluminum was used as a target, argon was used as a discharge gas, and oxygen was used as a reaction gas. The film formation pressure was 0.1 Pa, and the ultimate film thickness was 50 nm.

(2-2) Formation of first organic layer On the plastic film on which the first inorganic layer is formed, a monomer 20 g having the composition shown in Table 1 and an ultraviolet polymerization initiator (commercially available under the trade name of Ciba Irgacure 184) A mixed solution of 0.6 g and 2-butanone 200 g was applied using a wire bar so as to have a liquid thickness of 5 μm. After drying at room temperature for 2 hours, it was cured by irradiating with ultraviolet light from a high-pressure mercury lamp (integrated irradiation amount: about ² J / cm ² ) to form a first organic layer. The film thickness was about 500 nm in all cases.

(2-3) Formation of Second Inorganic Layer A second inorganic layer was formed on the first organic layer in the same manner as the first inorganic layer.

(2-4) Formation of second organic layer A second organic layer was formed on the second inorganic layer in the same manner as the first organic layer.

(2-5) Formation of third inorganic layer A third inorganic layer was formed on the second organic layer in the same manner as the first inorganic layer.

(2-6) Formation of third organic layer A third organic layer was formed on the third inorganic layer in the same manner as the first organic layer.

(2-7) Formation of 4th inorganic layer The 4th inorganic layer was formed on the 3rd organic layer by the method similar to the 1st inorganic layer.
As described above, the barrier film substrates (BF-1 to 5) of the present invention were produced.

(3) Physical property evaluation of barrier film substrate The physical properties of the barrier film substrate (BF-1 to 5) were evaluated by the following methods.

(3-1) Water vapor transmission rate Using a “PERMATRAN-W3 / 31” manufactured by MOCON, 20 water vapor transmission rates at 40 ° C./90% relative humidity were measured for each sample. In all samples, the water vapor transmission rate was less than the detection limit (estimated to be 0.01 g / m ² · day or less) at the majority of the measurement sites.
The part which gave the finite value which water vapor permeability was observable was considered as the failure part of the barrier film substrate. The probability of finding a normal site in 20 locations was defined as the yield and expressed as a percentage.

(3-2) Film Strength The film strength of the barrier layer was examined by a method (cross-cut peeling method) based on JIS K5600-5-6 (ISO 2409). The evaluation value was expressed as a ratio (percentage) of the area where film destruction did not occur.

(3-3) Evaluation Results Table 2 shows the physical property values of the barrier film substrates (BF-1 to 5) examined as described above. It can be seen that BF-2 to -5, which are the barrier film substrates of the present invention, are higher in yield and film strength than BF-1 in the comparative example. It can also be seen that the higher the monomer content in the present invention, the higher the yield and the higher the film strength.

[Example 2]
-Fabrication and evaluation of organic EL elements-
(1) Production of organic EL element The above-mentioned barrier film substrate (BF-1 to BF-5) is introduced into a vacuum chamber, and is made of an ITO thin film having a thickness of 0.2 μm by DC magnetron sputtering using an ITO target. An electrode was formed. A barrier film substrate having an ITO film was placed in a cleaning container, subjected to ultrasonic cleaning in 2-propanol, and then subjected to UV-ozone treatment for 30 minutes. The following organic compound layers were sequentially deposited on this substrate (anode) by vacuum deposition.

(First hole transport layer)
Copper phthalocyanine: film thickness 10nm
(Second hole transport layer)
NPD: film thickness 40nm
(Light emitting layer and electron transport layer)
Alq: 60 nm film thickness

Finally, 1 nm of lithium fluoride and 100 nm of metal aluminum were sequentially deposited to form a cathode.
This is placed in a glove box substituted with argon gas without being exposed to the atmosphere, and sealed with a glass sealing can and an ultraviolet curable adhesive (XNR5516HV, manufactured by Nagase Ciba Co., Ltd.). Thus, organic EL elements (OEL-1 to OEL-5) were obtained.

(2) Evaluation of organic EL element A voltage of 9 V was applied to the organic EL elements (OEL-1 to OEL-5) to emit light. All the elements showed green light emission derived from Alq.

(3) Evaluation of wet heat storage property The organic EL device (OEL-1 to 5) was stored for 3 days under the condition of 60 ° C. and 90% relative humidity, and then light was emitted by applying a voltage of 9V. When the light emitting surface was observed with a microscope, dark spots were observed in OEL-1. On the other hand, no dark spots were observed in OEL 2 to 5.

  From the above results, the barrier film substrate of the present invention has a high barrier property against water vapor and a high film strength. Further, it is obvious that when used as an organic EL substrate, dark spots are not generated.

Claims (9)

  A barrier film substrate having a plastic film and an alternating laminate composed of at least one organic layer and at least two inorganic layers on the plastic film, wherein the organic layer contains a polymer having an isocyanate group A barrier film substrate characterized by that. The barrier film substrate according to claim 1, wherein the polymer having an isocyanate group has a structure derived from a vinyl monomer represented by the following general formula (1).

[In General Formula (1), R ¹¹ represents a hydrogen atom or an alkyl group, L ¹ represents a linking group, and a11 and a12 each independently represents an integer of 1 to 4. ] The barrier film substrate according to claim 2, wherein R ¹¹ in the general formula (1) is a hydrogen atom.   The organic layer includes a polymer having a structure derived from a vinyl monomer having at least one hydroxyl group and at least one acrylate or methacrylate group in the molecule. The barrier film substrate according to Item. The vinyl monomer unit having at least one hydroxyl group and at least one acrylate or methacrylate group in the molecule is a vinyl monomer represented by the following general formula (2). Barrier film substrate.

[In General Formula (2), R ²¹ represents a hydrogen atom or an alkyl group, L ² represents a linking group, and a ^{21 and a 22} each independently represent an integer of 1 to 4. ]   The barrier film substrate according to claim 1, wherein at least one of the inorganic layers includes an oxide, nitride, or oxynitride of an element selected from Si and Al. . The barrier film substrate according to any one of claims 1 to 5, which has a water vapor transmission rate of 0.01 g / m ² · day or less at 40 ° C and 90% relative humidity.   The glass transition temperature of the said plastic film is 200 degreeC or more, The barrier property film substrate of any one of Claims 1-6 characterized by the above-mentioned.   The organic electroluminescent element using the barrier film substrate of any one of Claims 1-7.