JP2005212230A - Transparent gas barrier film and electroluminescence element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transparent gas barrier film having a high gas barrier capacity and not deteriorated in its gas barrier capacity even if bent, and an electroluinescence element free from deterioration or the occurrence of a defect using the same. <P>SOLUTION: The transparent gas barrier film has a structure that at least one organic layer and at least one inorganic layer are laminated at least on one side of a resin substrate and is characterized in that the oxygen permeability at a measuring temperature by an equal pressure method of 40°C is 1.0 cc/m<SP>2</SP>/day/atm or below and the value of activation energy of gas transmission thereof calculated from the temperature dependence of oxygen permeability thereof is 80 kJ/mol or below. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a gas barrier film that is excellent in transparency and has a high barrier property against the permeation of oxygen and water vapor, and an electroluminescence device using the same.

Japanese Patent Publication No.53-12953 Japanese Patent Publication No. 58-217344.

  Conventionally, a gas 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 substrate or film is used for wrapping articles, foods, industrial products and the like that need to block oxygen and water vapor. It is often used in packaging applications to prevent alteration of pharmaceuticals. In addition to packaging applications, it is used in liquid crystal display elements, solar cells, electroluminescence (EL) substrates, and the like. In particular, for transparent substrates that are being applied to liquid crystal display elements, EL elements, etc., in addition to demands for weight reduction and size increase, long-term reliability and high degree of freedom of shape are possible, and curved surface display is possible. As a result of such high demands, film base materials such as transparent plastics have begun to be used in place of glass substrates that are heavy, fragile and difficult to increase in area. In addition, the plastic film not only meets the above requirements, but also can be rolled-to-roll, so it has better productivity than a glass substrate and is advantageous in terms of cost reduction.

However, a film substrate such as a transparent plastic has a problem that gas barrier properties are inferior to a glass substrate. When such a base material having inferior gas barrier properties is used for the above-mentioned application, gas permeates and causes a problem. For example, the liquid crystal in the liquid crystal cell is deteriorated or the organic EL element is deteriorated to become a display defect and deteriorate the display quality. In order to solve such problems, it is known to form a metal oxide thin film on a film substrate to form a gas barrier film substrate. Gas barrier films used for packaging members and liquid crystal display elements are known in which silicon oxide is vapor-deposited on a plastic film (Patent Literature 1) and in which aluminum oxide is vapor-deposited (Patent Literature 2). A conventional gas barrier film has an oxygen permeability of about 1 cm ³ / m ² / day and a water vapor permeability of about 1 g / m ² / day.

  In recent years, further improvements in gas barrier performance to film substrates have been required due to the development of large-sized liquid crystal displays, high-definition displays, organic EL displays, and the like. Furthermore, there is a great demand for display devices that can be bent, and a barrier layer that does not deteriorate the gas barrier performance even when bent is required.

  An object of the present invention is to provide a transparent gas barrier film that has the high gas barrier performance required in the above-described conventional technology and does not deteriorate even when bent, and deterioration using the transparent gas barrier film An object of the present invention is to provide an electroluminescence element free from the occurrence of defects.

The transparent gas barrier film of the present invention has a structure in which one or more organic layers and inorganic layers are laminated on at least one surface of a resin substrate, and has an oxygen transmission rate by an isobaric method at a measurement temperature of 40 ° C. Is 1.0 cc / m ² / day / atm or less, and the gas permeation activation energy obtained from the temperature dependence of oxygen permeability is 80 kJ / mol or less.

  In the present invention, the inorganic layer is composed mainly of silicon oxide, silicon nitride, or silicon nitride oxide.

  In the present invention, the resin substrate is preferably a polyethylene naphthalate (PEN) film. The transparent gas barrier film of the present invention preferably has a total light transmittance of 80% or more.

  The electroluminescent device of the present invention is a laminate in which at least a transparent electrode layer, a light emitting layer, and a cathode layer are sequentially laminated on a base material, which is disposed in a sealed space. The transparent gas barrier film is used.

Embodiments of the present invention will be described below.
First, each constituent layer and production method of the transparent gas barrier film of the present invention will be described. FIG. 1 is a schematic cross-sectional view of an example of the gas barrier film of the present invention. The gas barrier film is provided by sequentially laminating an organic layer 2 and an inorganic layer 3 on a resin substrate 1. In the present invention, a plurality of organic layers and inorganic layers may be present, and the stacking order is not particularly limited, and any of them may be provided so as to be in direct contact with the resin substrate. For example, a layer configuration in which a plurality of organic layers and inorganic layers are alternately stacked on a resin substrate, a layer configuration in which organic layers made of different materials are stacked adjacent to each other, and inorganic layers made of different materials are adjacent to each other. And a laminated layer structure. In particular, a layer structure in which an organic layer, an inorganic layer, and an organic layer are sequentially provided on a resin substrate is preferable.

The transparent gas barrier film having the above layer structure of the present invention needs to have an oxygen permeability of 1.0 cc / m ² / day / atm or less by an isobaric method at a measurement temperature of 40 ° C., preferably 0.1 cc / M ² / day / atm or less, particularly preferably 0.01 cc / m ² / day / atm or less. The value of oxygen permeability at a measurement temperature of 40 ° C. can be measured, for example, by the Mokon method (manufactured by MOKON, OX-TRAN), which is a method according to JIS K-7126B.

 The transparent gas barrier film of the present invention needs to have a gas permeation activation energy value of 80 kJ / mol or less determined from the temperature dependence of oxygen permeability. The activation energy for gas permeation can be determined by measuring the oxygen permeability in the range of 10 to 40 ° C. by the Mocon method and determining the temperature dependence of the oxygen permeability. That is, the activation energy of gas permeation is a value obtained from the following formula (1) from the Arrhenius plot based on the temperature dependence of oxygen permeation in the method of measuring oxygen permeation according to JIS K-7126B.

Π = Π ₀ exp (−ΔE _p / RT) (1)
Where
：: Oxygen transmission rate Π ₀ : Pre-exponential factor ΔE _p : Activation energy
R: Gas constant (8.3144 × 103kJ / K-mol)
T: Absolute temperature.

That is, the Arrhenius plot is a plot in which the left side lnΠ of the following formula (2) taking the logarithm of both sides of the formula (1) is plotted on the vertical axis and l / T on the right side is plotted on the horizontal axis. The activation energy is calculated from ΔE _p / R.
lnΠ = lnΠ ₀ − (ΔE _p / R) / T (2)

 In other words, the Arrhenius plot represents the temperature dependence of oxygen permeability, and when the activation energy value is small, that is, when the slope of equation (2) is small, the temperature dependence of oxygen permeability is small, A stable oxygen transmission rate can be obtained at a temperature, and a good film having no temperature dependency is obtained as a gas barrier film. On the contrary, when the value of activation energy is high, the slope of the formula (2) becomes large, which means that the dependence on temperature is large, and a gas barrier film having temperature dependence is obtained.

 In order to keep the activation energy value low, the number of organic layers and inorganic layers can be increased, the film thickness can be increased, and the inorganic layer film with few defects can be optimized by optimizing the film forming conditions of the inorganic layer. And a method of reducing defects of films and films by increasing the adhesion between layers, a method of using materials having low temperature dependence, and the like.

  In the present invention, the resin substrate is not particularly limited as long as it is a film formed of an organic material capable of holding a film having a barrier property. Specifically, homopolymers such as ethylene, propylene, butene, or polyolefin resins such as copolymers or copolymers, amorphous polyolefin resins such as cyclic polyolefin, polyethylene terephthalate resin, polyethylene-2,6-naphthalate, etc. Polyester resins, nylon 6, nylon 12, polyamide resins such as copolymer nylon, polyvinyl alcohol resins, polyvinyl alcohol resins such as ethylene-vinyl alcohol copolymer, polyimide resins, polyetherimide resins, polysulfone resins, poly Ether sulfone resin, polyether ether ketone resin, polycarbonate resin, polyvinyl butyrate resin, polyarylate resin, fluorine-based resin, and the like can be used. Among these, polyethylene naphthalate resins such as polyethylene-2,6-naphthalate resin have good gas barrier properties, and particularly low oxygen permeability and water vapor permeability. Therefore, in the present invention, a polyethylene naphthalate film is used as the resin substrate. It is preferable to use it. The thickness of these resin films is preferably 12 to 500 μm. Moreover, it is necessary for transparency to be high.

  The organic layer provided on the resin substrate is not particularly limited, and acrylic resin, urethane resin, epoxy resin, polyester resin, olefin resin, fluorine resin, silicon resin, and the like can be used. The thickness of the organic layer is not particularly limited, but is preferably in the range of 0.1 μm to 10 μm. The organic layer provided on the resin substrate plays a role of smoothing the surface of the resin substrate. In addition, when flexibility is taken into consideration, it also plays a role of preventing cracking of the inorganic layer due to bending. In addition, by providing the organic layer with functions such as water repellency performance, water absorption performance, oxygen adsorption performance, etc., the gas barrier performance can be further improved. Therefore, a resin having water repellency performance, water absorption performance, oxygen adsorption performance. It is also possible to add additives. Further, the organic layer needs to have high transparency.

 The organic layer can be formed by coating a solution obtained by dissolving the above resin in an appropriate solvent on a resin substrate by a known method such as roll coating, gravure coating, knife coating, dip coating, spray coating or the like.

  The inorganic layer is mainly composed of silicon oxide, silicon nitride, or silicon nitride oxide from the balance of transparency, gas barrier properties, flexibility, and the like. The thickness of the inorganic layer is preferably in the range of 1 nm to 500 nm. Furthermore, the range of 10-300 nm is more preferable. If the inorganic layer is thicker than the above range, cracks may occur with respect to bending stress, and if it is too thin, the film will not be uniform and the barrier performance will be reduced. As a method for forming the inorganic layer, a resistance heating vapor deposition method, an electron beam vapor deposition method, an ion plating method, a CVD method, a plasma CVD method, a sputtering method, etc. can be applied, and any method can be used as long as the target inorganic layer can be obtained. There is no.

  The transparent gas barrier film of the present invention has a layer structure in which one or more organic layers and inorganic layers are laminated on at least one surface of a resin substrate, and is particularly used for displays such as liquid crystal display elements and organic EL elements. In this case, since high gas barrier performance is required, it is preferable to stack two or more organic layers and inorganic layers so as to meet high gas barrier performance requirements. Moreover, you may laminate | stack an organic layer and an inorganic layer on both surfaces of a resin substrate, and it is preferable to laminate | stack so that it may become a vertically symmetrical structure in that case. When the organic layer and the inorganic layer are laminated on both surfaces of the resin substrate, an effect of reducing the warp of the transparent gas barrier film is produced.

  The final gas barrier film laminated preferably has transparency. For example, as a measure of transparency, the total light transmittance is preferably 80% or more, more preferably 88% or more. The total light transmittance is measured according to JIS K7136-1.

Next, the structure and manufacturing method of the electroluminescence element of the present invention will be described.
FIG. 2 is a schematic cross-sectional view of the electroluminescence element of the present invention. In the figure, an electroluminescent element is formed by sequentially laminating a transparent electrode layer 4, a light emitting layer 5, and a cathode layer 6 on a substrate 10, and the laminated body is sealed with a sealing material and disposed in a sealed space. It has a structure. In FIG. 2a, this laminate is sealed with a sealing material 7a formed of a metal material, plastic, or the like, and in FIG. 2b, it is sealed with a sealing material 7b made of a resin material such as a transparent gas barrier film. Shows the case.

  As the substrate, the transparent gas barrier film described above is used.

  The transparent electrode layer has a function as an anode for supplying holes to the light emitting layer. For example, tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), indium zinc oxide (IZO), etc. Metals such as conductive metal oxides, gold, silver, and aluminum can be used, and the shape, structure, size, and the like are not particularly limited. The method for producing the transparent electrode layer may be appropriately selected from the vacuum deposition method, the sputtering method, the ion plating method, the CVD method, the plasma CVD method and the like in consideration of suitability with the material. The patterning of the transparent electrode layer can be performed by a chemical etching method using photolithography, a physical etching method using a laser, a vacuum evaporation method using a mask, a sputtering method, a lift-off method, a printing method, or the like. The thickness is suitably in the range of 10 nm to 5 μm.

  The light emitting layer contains at least one kind of light emitting material, and if necessary, a hole injecting material, a hole transporting material, an electron injecting material, and an electron transport that facilitate the generation and movement of holes and electrons. Materials and the like may be included. Further, a hole injecting material, a hole transporting material, an electron injecting material, an electron transporting material, or the like may be stacked on the light emitting layer as a layer different from the light emitting layer.

  Examples of luminescent materials include benzoxazole derivatives, benzimidazole derivatives, benzothiazole derivatives, styrylbenzene derivatives, polyphenyl derivatives, diphenylbutadiene derivatives, tetraphenylbutadiene derivatives, naphthalimide derivatives, coumarin derivatives, perylene derivatives, perinone derivatives, oxadiazoles. Derivatives, aldazine derivatives, pyralidine derivatives, cyclopentadiene derivatives, bisstyrylanthracene derivatives, quinacridone derivatives, pyrrolopyridine derivatives, thiadiazolopyridine derivatives, styrylamine derivatives, aromatic dimethylidene derivatives, 8-quinolyl derivatives metal complexes and rare earth complexes Representative metal complexes, polythiophene derivatives, polyphenylene derivatives, polyphenylene vinylene derivatives, polyfluorene derivatives Molecular compound, and the like. These can be used alone or in combination of two or more.

  As the hole injecting material and the hole transporting material, both a low molecular hole transporting material and a polymer hole transporting material can be used, a function of injecting holes from the anode, a function of transporting holes, and There is no limitation as long as it has one of the functions of blocking electrons injected from the cathode. Examples of hole transport materials include carbazole derivatives, triazole derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, Styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aromatic tertiary amine compounds, styrylamine compounds, aromatic dimethylidene compounds, porphyrin compounds, polysilane compounds, poly (N-vinylcarbazole) derivatives, Conductive polymer oligomer such as aniline copolymer, thiophene oligomer, polythiophene, polythiophene derivative, polyphenylene derivative, polyphenylene Vinylene derivatives, polymer compounds such as polyfluorene derivatives, and the like. These may be used alone or in combination of two or more.

  The electron injecting material and the electron transporting material are not limited as long as they have either a function of transporting electrons or a function of blocking holes injected from the anode. For example, triazole derivatives , Oxazole derivatives, oxadiazole derivatives, fluorenone derivatives, anthraquinodimethane derivatives, anthrone derivatives, diphenylquinone derivatives, thiopyrandioxide derivatives, carbodiimide derivatives, fluorenylidenemethane derivatives, distyrylpyrazine derivatives, naphthaleneperylene, etc. Metal complexes of cyclic tetracarboxylic acid anhydrides, phthalocyanine derivatives, 8-quinolinol derivatives, metal phthalocyanines, metal complexes represented by benzoxazole and benzodiazole ligands, aniline copolymers, Thiofenori Mer, polythiophene derivatives, polyphenylene derivatives, polyphenylene vinylene derivatives, polymer compounds such as polyfluorene derivatives. These may be used alone or in combination of two or more.

  The light emitting layer can be suitably formed by a dry method such as vapor deposition or sputtering, or a wet method such as dipping, spin coating, dip coating, casting, die coating, roll coating, bar coating, or gravure coating. These film forming methods can be appropriately selected according to the material of the light emitting layer. The film thickness is generally set in the range of 1 nm to 10 μm, preferably 10 nm to 1 μm. A hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer can also be produced in the same manner as in the case of the light emitting layer.

  The cathode layer is not particularly limited in shape, structure, size and the like, and may function as an electrode for injecting electrons into the light emitting layer. The shape, structure, size, etc. are not particularly limited, but the thickness is suitably in the range of 10 nm to 5 μm. Examples of the cathode material include alkali metals (eg, Li, Na, K, Cs, etc.), alkaline earth metals (eg, Mg, Ca, etc.), gold, silver, lead, aluminum, sodium-potassium alloy, lithium-aluminum alloy, Examples include magnesium-silver alloys, rare earth metals such as indium and ytterbium. Of these, two or more types may be used in combination.

  The cathode layer can be formed by vacuum deposition, sputtering, ion plating, CVD, plasma CVD, or the like, and may be selected as appropriate in consideration of suitability with the cathode material. For the patterning of the cathode, physical etching using photolithography, laser, etc., vacuum deposition method using a mask, sputtering method, lift-off method, printing method, or the like can be employed.

 A known material such as an aluminum tube is used as the sealing material, but the transparent gas barrier film in the present invention may be used as the sealing material.

  As described above, the transparent gas barrier film of the present invention has a specific oxygen permeability and an activation energy value for gas permeation, so it has higher gas barrier performance than the conventional one, is transparent, and its barrier properties deteriorate even when bent. A transparent gas barrier film can be obtained. Then, by using the transparent gas barrier film, an electroluminescence element free from deterioration and defects can be obtained.

Next, a further preferred embodiment of the present invention will be described. A preferred transparent gas barrier film of the present invention is composed of a polyethylene naphthalate film as a resin substrate, an acrylic resin as an organic layer, and silicon oxide, silicon nitride, or silicon nitride oxide as an inorganic layer. The oxygen permeability measured by the isobaric method at a measurement temperature of 40 ° C. is 0.01 cc / m ² / day / atm or less, and the activation energy of gas permeation obtained from the temperature dependence of the oxygen permeability is The value is 40 kJ / mol or less.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited to a following example.

  A polyethylene naphthalate film (100 μm) is used as a resin substrate, and an organic layer is coated with an acrylic resin (Dainippon Ink Chemical Co., Ltd. Unidic V-4263) with a photopolymerization initiator added to a thickness of 1 μm. Then, it was cured by applying ultraviolet rays, and then silicon oxide was laminated as an inorganic layer. As a stacking method, a plasma CVD method was used, and a silicon oxide film having a thickness of 100 nm was stacked using tetramethoxysilane and oxygen gas as starting materials. Furthermore, an acrylic resin layer was applied to the outermost layer to produce a transparent gas barrier film.

  A polyethylene naphthalate film (100 μm) is used as a resin substrate, and an organic layer is coated with an acrylic resin (Dainippon Ink Chemical Co., Ltd. Unidic V-4263) with a photopolymerization initiator added to a thickness of 1 μm. Then, it was cured by applying ultraviolet rays, and then silicon oxide was laminated as an inorganic layer. As a stacking method, a plasma CVD method was used, and a silicon oxide film having a thickness of 100 nm was stacked using tetramethoxysilane and oxygen gas as starting materials. Further, another organic layer and an inorganic layer were alternately laminated in the same manner as described above, and an acrylic resin layer was applied to the outermost layer to produce a transparent gas barrier film having two inorganic layers.

  A polyethylene naphthalate film (100 μm) is used as a resin substrate, and an organic layer is coated with an acrylic resin (Dainippon Ink Chemical Co., Ltd. Unidic V-4263) with a photopolymerization initiator added to a thickness of 1 μm. Then, it was cured by applying ultraviolet rays, and then silicon oxide was laminated as an inorganic layer. As a stacking method, a plasma CVD method was used, and a silicon oxide film having a thickness of 100 nm was stacked using tetramethoxysilane and oxygen gas as starting materials. Further, two organic layers and two inorganic layers were alternately laminated in the same manner as described above, and an acrylic resin layer was applied to the outermost layer to produce a transparent gas barrier film having three inorganic layers.

(Comparative Example 1)
A polyethylene naphthalate film (100 μm) itself as a resin substrate was used.
(Comparative Example 2)
A polyethylene naphthalate film (100 μm) as a resin substrate was used, and silicon oxide was laminated thereon as an inorganic layer. As a lamination method, a plasma barrier CVD method was used, and a gas barrier film in which tetramethoxysilane and oxygen gas were used as starting materials and a silicon oxide film having a thickness of 100 nm was laminated was produced.

(Evaluation)
Conditions of temperature 10, 20, 30, 40 ° C./90% humidity using oxygen permeability measuring device (manufactured by MOKON, OX-TRAN 2/21 ML) for oxygen permeability of the films prepared in Examples and Comparative Examples Measured with The activation energy was obtained from an Arrhenius plot obtained by plotting the measured oxygen permeability value as a reciprocal of absolute temperature.

  The total light transmittance is a value measured using a haze meter (Haze Meter NDH2000, manufactured by Nippon Denshoku). The oxygen permeability after bending is a measured value after a transparent gas barrier film is wound around a cylindrical rod having a diameter of 2 cm.

The typical sectional view of the transparent gas barrier film of the present invention. 1 is a schematic cross-sectional view of an electroluminescence element of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Resin substrate, 2 ... Organic layer, 3 ... Inorganic layer, 4 ... Transparent electrode layer, 5 ... Light emitting layer, 6 ... Cathode layer, 7a, 7b ... Sealing material, 10 ... Base material (transparent gas barrier film).

Claims (5)

In a gas barrier film having a structure in which one or more organic layers and inorganic layers are laminated on at least one surface of a resin substrate, the oxygen transmission rate by an isobaric method at a measurement temperature of 40 ° C. is 1.0 cc / m ² / day / atm. A transparent gas barrier film having a gas permeation activation energy value of 80 kJ / mol or less determined from the temperature dependence of oxygen permeability.   The transparent gas barrier film according to claim 1, wherein the inorganic layer contains silicon oxide, silicon nitride, or silicon nitride oxide as a main component.   The transparent gas barrier film according to claim 1, wherein the resin substrate is a polyethylene naphthalate film.   4. The transparent gas barrier film according to claim 1, wherein the total light transmittance is 80% or more. In an electroluminescent device in which a laminate in which at least a transparent electrode layer, a light emitting layer, and a cathode layer are sequentially laminated on a base material is disposed in a sealed space, the base material is organic on at least one surface of a resin substrate. A gas barrier film having a structure in which one or more layers and one or more inorganic layers are laminated and having an oxygen transmission rate of 1.0 cc / m ² / day / atm or less by an isobaric method at a measurement temperature of 40 ° C. An electroluminescence device comprising a transparent gas barrier film having a gas permeation activation energy value of 80 kJ / mol or less determined from the temperature dependency of transmittance.

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